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Gallery, Projects and General => Project Logs => Topic started by: S. Heslop on September 06, 2018, 02:20:15 AM

Title: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 02:20:15 AM
The two go hand in hand.

So i've been planning this for quite a while now but other things kept coming up. I'd like a large 3d printer, about 400x400x500 build volume, but the price they charge for commercial ones is taking the mick and i'm sure I could build one for a fraction of the cost. I've just been very indecisive on how to go about it.

One of the earlier designs I settled on was this.

(https://i.imgur.com/7lzsfRK.jpg)

CoreXY gantry, sheet metal construction. But I was pricing out how to build a box and pan folder before thinking that idea was getting a bit expensive, and I started to dislike the design i'd come up with.

So then I settled on this.

(https://i.imgur.com/40k7XhT.jpg)

It's a bit of a mess of a design. But I started building it anyways. I couldn't find the nice 50x100 thin walled ESR tubing I had in mind so I went for some 50x100x3mm hot rolled. I think they might've mucked the order up because the walls are more like 4mm. Just the steel for the sides was impossible to lift on my own, so I set out hole sawing bits away. I got two holes put in before deciding it wasn't a great idea. I'm not to keen on the design either. There's some real flaky bits. (This is an older screenshot I just realised. It really started to fall apart when adding the details)

I'm here right now.

(https://i.imgur.com/0AlUAX7.jpg)

Not much to look at, but i'm going for yet another gantry arrangement, copied from a popular commercial machine. Seems it'd be alot easier to build than having to worry about routing miles of belt, and everything fits nicely against the walls of a square box. I've not quite figured out the box part yet though. Seems the routes to take are a welded box section frame with panels bolted/ welded on, big chunky aluminium/ plastic plates that weld or bolt together, or a sheet metal box of some sort.


I've always wanted to do more with sheet metal. If nothing else I think it's cool! So building a big box and pan folder is appealing. Here's the design I was going with previously.

(https://i.imgur.com/eddwHzo.jpg)

The idea was to rely on cold rolled steel being fairly straight to register the fingers against. There'd be a bolt going through that hole to pull that clamp up.

(https://i.imgur.com/GrAz4Yi.jpg)


But I just saw this video (https://www.youtube.com/watch?v=BAdEOJikVyA). It's a little hard to make out but I think at the start he welds some tiny angles onto a flat to make the T tracks. And I think trying to register on the tops of the fingers is alot more complicated than just registring the bottoms against the table, especially since i'd be making them by hand with most likely a belt sander, so the T track might not need to be that accurate. It'd also be nice to come up with a new design that can make use of all that 100x50xsomething rectangle.


I'm also considering the idea of buying one of the cheaper 3d printers out there to make some parts, and then pillaging it for the steppers. For what was the hot adult nerd toy a couple years ago i'm surprised there's not much of a second hand market for them. Maybe the sales weren't as big as the journalism made them out to be. I've kinda wondered why the Chinese devices look so... prototypal - being assembled from stock parts, laser cut acrylic, and aluminium profiles.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 06, 2018, 03:34:24 AM
I would highly recommend MGN12 linear slides over smooth rods. They are cheap and more than accurate for this application.
https://www.ebay.co.uk/itm/MGN12-250-550mm-Miniature-Linear-Rail-Slide-Carriage-Kossel-3D-Printer-CNC-Laser/382529570288?hash=item59108a05f0:m:mKynaPd9azC-mDeASbymloA

Why not use aluminium extrusions in the size of your choice? You can have them delivered pre-cut from Motedis accurate to less than a mm
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 03:49:57 AM
Huh they seem alot cheaper than last time I looked. I think I was looking at £120 a set back then. I got given 4 bearing blocks and i've got the steel bar as well, so I might stick with round rails for the Z axis. But it opens up options for the X/Y gantry.

Extrusions were the first thing I looked at, but I thought all the brackets you'd need to get everything in the right place would be tricky to make. Alot of the designs using those rely on alot of 3d printed parts. But back then I was also trying to avoid using 3d printed parts...

Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 06, 2018, 04:17:36 AM
I am trying to bite my lip commenting here, but those long Z bars....  Think about using a 300mm lever on them pivoting about the leadscrew.  They are going to move even under light pressure from the nozzle.  Supported is the way to go, round or rail.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 04:44:52 AM
I am trying to bite my lip commenting here, but those long Z bars....  Think about using a 300mm lever on them pivoting about the leadscrew.  They are going to move even under light pressure from the nozzle.  Supported is the way to go, round or rail.

Hah don't worry, I appreciate the comment. With the earlier designs I was going in the opposite direction with 20mm round bars. But like I said I gave up on it because it was going to be absurdly heavy - so i'm kinda going in the opposite direction now. My concern was that putting more weight on the table would make the layers fan out over the whole item (combined with it reaching the mid point of the bars where I believe it'd flex more). I'm also hoping that I could find somewhere to have the stepper motor at the top of the leadscrew so that it's hanging and held in tension, which I think would let you get away with a fairly spindly one.

I've read a few arguments on CNC forums over round vs supported and they never seemed to reach a conclusion. The idea being that the cut-out in the bearings makes them considerably weaker than if you just used unsupported rods and enclosed bearings. But the appealing part of round rods for me is that I don't need to worry about their mounting being straight or shimmed along their length. Just need the ends in the right place.

Looking at commercial machines they all look surprisingly under-built to me.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 06, 2018, 05:25:01 AM
A 3D printer does not need huge amounts of structural rigidity. Vibration and resonance are more of a problem. It would be far more productive for you to use your time in vibration control rather than building a substantial chassis. Make the gantry as light and vibration free as possible.

Some of the kits on Banggood and Aliexpress are not a bad place to start IMHO. Just keep the bits you need and beef up or change what you don't like .
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 06, 2018, 05:33:56 AM
Table sag is an issue, especially with larger heavier prints.  As can be seen in some of my tall prints, if the setup isnít rigid you will get banding as the print/machine flex.  I get good results partly due to the small size of my printer and the steel welded chassis.  Scaling it up and keeping the bars same size, as seems to be the norm in the hobby class machines, is not a good recipe for precision.

You also need to think about the nozzle being in the centre position when extruding.  The pressure at the nozzle is easily able to lift/bend a lightly constructed XY mechanism, never mind push down the table.  That leads to mid print bulge and outer edges, corners getting squashed or distorted.  It only takes a few thou movement to go from a good to bad print if you are trying to hold close tolerance on parts and crisp sharp corners.  Heavy design is good, where itís needed, vibration will show in your prints as banding or echo of printed detail.

Have a think about keeping the table fixed and moving the XY mechanism up and down for a large printer.  Those eBay rails look tempting, but I would want to do some serious testing on them first.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 06, 2018, 06:21:16 AM
The MGN12 rails are very good for the price. I have about 10 of them (all half finished projects). There is very little play between rail and carriage in any direction. They are well made and finished. The grinding (on all mine at least) is flat and parallel. The only discernible flaws on mine are that some of them feel slightly gritty when they run on the rails. It doesn't affect movement much when there is a bit of force applied to the carriages but the difference in friction is evident under just gravity. I tried washing them out with paraffin and re-greasing but it didn't make a huge difference. I think the problem is the finish on the bearing surface of the carriages rather than dust or grit.

There are countless builds on the reprap forum using these rails (some of them very high spec indeed) and hardly anyone has issues with their actual performance in real life. The performance of other mechanical components like stepper motors, timing belts & pulleys and the physics of molten plastic become an issue well before these rails reach their limit.

They are noisier than igus bearings  or delrin wheels.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 08:16:45 AM
I never knew about the pressure from the head flexing things. From what i'd read it was people just chasing vibrations. That said I have seen videos where people had really long nozzles that you could see twisting about as the motors changed direction.

Keeping the table fixed and moving the XY up is also one of the first thoughts I had. I forget why I dropped it for the Z axis bed... the only reason I can think of right now is trying to reduce the overall size of the machine. I think I also had a hard time finding examples of such machines to copy.

I've got alot of 12mm bar. It's just cold rolled, I figured that'd be good enough. Or I at least wanted to try see if it's good enough since it's not too expensive and still useful if I switch it out. And 4 12mm linear bearings i'm keen to use. So right now i'm thinking a coreXY deal built on a 2mm steel sheet, since i've still got loads of that stuff, bent up around the edges that haven't got a linear guide on it for stiffness.... and then that's lifted by 2 or maybe 3 leadscrews.

Y'know if I made the vertical guides stiff enough then everything could be supported on the base. I wouldn't even need sides except to keep the breeze out.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: PK on September 06, 2018, 08:47:12 AM
A 3D printer does not need huge amounts of structural rigidity.
My lip hurts.....
A 3d printer needs LOTS of structural rigidity in X and Y because it runs at high accelerations which generate large forces even with lightweight heads.
A 3d printer needs LOTS of mass because it moves repetitively  in almost every direction so your only hope is to have the resonant frequency of the structure below every conceivable excitation frequency and the best way to do that is make it massive.

The reason this sounds wrong is because you never see commercial 3d printers built this way and *that* is because a). it's such a price competitive market, and b). they have to be shipped.
Instead you spend you time and money on 32bit controllers trying to tune 3rd order jerk parameters to get the thing to stay still.


There... I feel better now!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 12:44:45 PM
I guess the deal is that FDM style 3d printing isn't so useful unless it's cheap and available. You could build an insane machine in the style of a pick and place gantry but then you'd still be squirting out globs of plastic into a wobbly shape. I was looking at 5 axis CNC carving machines before I admitted 3d printing would be alot simpler and cheaper.

Earlier today I bumbled into one of those metal 3d printing company's websites and noticed they'd STOLEN MY IDEA. The idea being to 3d print parts from whatever metal filled plastic they use in metal injection moulding then process it in the same manner. It's an idea thats so obvious i'm sure alot of people considered it, but I dropped it myself when I realised that by the time you've gone and built a hydrogen furnace and figured out the whole solvent processing step you might as well have bought a nice milling machine and all the attachments.

Those SLA machines seem interesting, as do the inkjet type, for producing highly detailed (and even coloured) models for more artistic purposes. For actual sculpting of one-offs it'd probably still be easier to go with clay and molds than do it in software. But they did make an interesting use of those machines in a couple of stop motion films. But again it was kinda self defeating since they more or less just made a CG film with all the animated faces, then exported them out into models to photograph. They didn't have the uh... hideous charm of regular stop motion and just looked like low framerate CG films.



Also I gotta say that laptop kayzed1 sent has been a godsend. In the middle of a Windows reinstall and all kinds of things are going wrong. Mostly that driver providers seem to be dropping support for windows 7, or at least windows 7 freshly installed. Hoping installing all the updates stops the nvidea graphics card driver refusing to install otherwise i'm going to be digging for older versions.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 06, 2018, 01:27:12 PM
LOL, I will jerk about with a 32bit controller on my rebuild. 

Donít get too disheartened, you have seen the print quality I can produce on a cheap printer (or maybe that HAS put you off).  Just donít have your hopes up for high precision, especially with a large volume machine.  All the engineering prototype stuff I have done has fitted in a 150x150x200mm volume.  The newer model boat stuff isnít as critical on dimensions and the prints have some flex to work with.

Consider a cheap off the shelf machine for learning, a lot more to printing than just the mechanism of squirting plastic in XYZ
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 02:51:01 PM
LOL, I will jerk about with a 32bit controller on my rebuild. 

Donít get too disheartened, you have seen the print quality I can produce on a cheap printer (or maybe that HAS put you off).  Just donít have your hopes up for high precision, especially with a large volume machine.  All the engineering prototype stuff I have done has fitted in a 150x150x200mm volume.  The newer model boat stuff isnít as critical on dimensions and the prints have some flex to work with.

Consider a cheap off the shelf machine for learning, a lot more to printing than just the mechanism of squirting plastic in XYZ

Hah I originally typed up something much nastier in regards FDM print quality. Like I've seen a few proudly posted before and after shots of heavily stepped holes where i'm straining to see the difference.

I think you're right though about getting a ready to assemble machine. If nothing else I could rip the head and steppers out of it when I start finding I need the bigger one. I could also see how far I can get gluing together larger objects from sections. Bit of a dull conclusion to this thread though!


Also hey i'm back on the desktop. I was able to import my old firefox data, plugins cookies logins and all. It seems to be exactly as it was. And the windows update process also installed the graphics card and audio drivers for me. It's weird! I was cursing it when it started. Now I just gotta reinstall all the programs I actively use. I might try avoid sketchup this time and go with fusion 360. I'd tried it in the past but found it horrible. If nothing else the way autodesk wants to hold your working files hostage on their ~cloud~ is offputting.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 03:08:35 PM
Bahaha. Spoke too soon. Turns out I installed a 32 bit copy of windows. Guess I need to find the 64 bit iso and try again.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 04:01:21 PM
God damn it gets worse. I figured it was no big deal since Microsoft provides the isos on their website. The memory of doing that came back. But oops, turns out they changed that system and do a CD key check to make sure you're not using a dastardly OEM CD key before downloading.

So there's a bunch of shady crap to download the isos anyways, and I was mostly going on outdated info and tried running a program that now comes with a bitcoin miner. It at least has the decency to tell you as you start it. So I've dug the ol' torrent client from the old hard drive to download this iso from a website that people a year ago were saying is reputable. I'll try find more up to date info as it downloads.

Thing is that torrent client in later updates also added a bitcoin miner, so for a while people were sticking with the older versions. But a friend warned me a bit back that that version is compromised now and a big security risk to run. But what other option is there. I was hoping this'd be a nice clean install but now it feels dirty before i've even installed it!

Edit: Maybe it's time to dust off the old Micro$haft. Around windows 7 time I was starting to think maybe they'd turned it around. Then they abruptly dropped support for a bunch of their products, then they came out with the horrid tablet focussed windows 8, then they started adding telemetry and data collecting in updates. And now this!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 06, 2018, 04:16:46 PM
Ahhh Linux

 :wack:
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 04:21:50 PM
Ahhh Linux

 :wack:

I've considered it many times in my life.

A fun fact is that I got this windows 7 CD key when my sister got a virus on her new laptop, and I was down visiting a cousin for a few days. And by the time I got back her idiot boyfriend of the time managed to wipe it and install ubunto on the thing. In the end she complained enough that I put vista on it, and the family's been playing musical chairs with operating systems ever since.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: awemawson on September 06, 2018, 04:54:46 PM
I have two legitimate bought copies of WIN7Pro loaded on four PCs which you are allowed to do under the license terms. I recently had to change a motherboard when the video went up the spout on one of them, and went through all the hoops trying to re-authorise it. Neither key would work. Eventually I tried a key from a Dell small form factor that I bought pre-loaded (so don't have the CD) and it worked first time.

I know they need to control pirate copying, but it was stopping me do what I am allowed to do  :bang:
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 06, 2018, 05:09:54 PM
A 3D printer does not need huge amounts of structural rigidity.
My lip hurts.....
A 3d printer needs LOTS of structural rigidity in X and Y because it runs at high accelerations which generate large forces even with lightweight heads.
A 3d printer needs LOTS of mass because it moves repetitively  in almost every direction so your only hope is to have the resonant frequency of the structure below every conceivable excitation frequency and the best way to do that is make it massive.

The reason this sounds wrong is because you never see commercial 3d printers built this way and *that* is because a). it's such a price competitive market, and b). they have to be shipped.




Instead you spend you time and money on 32bit controllers trying to tune 3rd order jerk parameters to get the thing to stay still.


There... I feel better now!

You are probably technically correct but we are talking of home built printers for hobby use where time and the need to tweak things every now and then are not a major issue but cost is. If we judge every printer by the yard stick you describe, then reprap type and similar printers should have no right to function at all. Yet, there is enough evidence out there that lot of people are able to get what most hobbyists would regard as very good to even outstanding quality prints from surprisingly modest machines.

I don't want to side track Simon's thread, so I'll refrain from commenting any further on this. I am sure he can make up his own mind on how he wants to build his printer.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 05:13:26 PM
I have two legitimate bought copies of WIN7Pro loaded on four PCs which you are allowed to do under the license terms. I recently had to change a motherboard when the video went up the spout on one of them, and went through all the hoops trying to re-authorise it. Neither key would work. Eventually I tried a key from a Dell small form factor that I bought pre-loaded (so don't have the CD) and it worked first time.

I know they need to control pirate copying, but it was stopping me do what I am allowed to do  :bang:

I'm assuming its less piracy and more all those landfills full of trashed laptops and PCs with the little cd key stickers on them being picked up and resold online. And being able to download the iso from Microsoft itself makes it way less shady seeming.

When I was still at school and building my first PC, I asked the IT guy there for advise. And he went and got me a handful of Windows XP professional CDs. But it confused the hell out of me because he didn't also say to copy a key from one of the units, and I was too embarrased to tell him I couldn't make it work. They'd installed Windows NT or something on them all so over a whole school they mustve had at least 200 legit copies of Windows just up for grabs. If only I knew more about computers then. In the end an older kid got me a pirated copy of XP pro and even printed a custom label. That kid collected Psion netbooks which blew me away as a little glimpse into how cool the future of computing could be. And well you know how I feel about the future of computing now that i'm living in it...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 05:18:52 PM
I don't want to side track Simon's thread, so I'll refrain from commenting any further on this. I am sure he can make up his own mind on how he wants to build his printer.

It's already well sidetracked, don't worry about it. I'm hearing stuff that i've never heard when reading all the official 3d printer forums.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 06, 2018, 06:34:00 PM
The argument over 8bit and 32bit controllers is a little more complex than just jerk.

https://madmodder.net/index.php/topic,11247.msg132361.html#msg132361

Going back a couple of years, here is an example of print quality side by side., and controllers have come on a bit since then.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 06:53:39 PM
That is a very noticeable difference. What printer model do you currently run anyways, Joules? I've read your threads and I don't remember you saying what it specifically was.



Also update on computer stuff. I found the Last DVD-R and burned the .iso to that and it seems to be working. 55% extracted. I don't have alot of faith in burnable disks and this one is quite old. And hopefully it accepts the CD key!

I should... or maybe shouldn't add that i've also been feeling pretty terrible today with uh... regular trips to the toilet. I'd say that's bad but really it's kept me busy during load times! I've also been up for way too long but there's no way I could get to sleep with this hanging over me.

Oh just Expanded and installed. I'll probably set it to download updates overnight and try get to sleep if it's worked.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: PK on September 06, 2018, 07:00:24 PM
The argument over 8bit and 32bit controllers is a little more complex than just jerk.

Agreed.

I do see a lot of "how to remove ringing" and "the top 10 tips for fixing banding in your prints" articles though.

Half decent linear motion bits are cheaper than they've ever been.  There was a time when I had a rule of thumb of $500 per axis for a DIY CNC machine. You can do a reasonable job for half that now.

The real problem is that 8mm ground rod and slightly wonky acme leadscrews can be had for less than postage... Oh, and don't get me started on moving axii with rubber bands! :-)

As I mentioned elsewhere, I got as far as some 20mm hot rolled steel plate, rough cut and a deal with the CNC shop over the road to put some precision surfaces on it. IIRC the metal was around $100. Total budget for the machine was <$1k.

My problem is that the plastic snotters just don't suit what I/we do. Heck, maybe one day I'll just make one to win the argument...

I do enthusiastically acknowledge the merit of a DIY machine build at any level though. If valuing my opinion results in something not getting built then that's a MUCH worse outcome than having a go and enjoying the process.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 06, 2018, 07:07:05 PM
I have 3 older Createbot Miniís.  The touch screen versions are not an improvement...  They really went to town getting the cost/quality down 8-(   Maybe they raised their game again, but looking at the review ratings I think not.  A couple of Mini Kossel printers, but they still out fox me with the complex setup every time you change the firmware, I will get the better of them. A now defunct Printrbot Metal Plus is the last on the list and being rebuilt with a newer 32bit Duet board and E3D hot end.  Some of the old printing posts mention the Mini printer.   Prior to all that I started out with a loaned Rostock Max 8bit delta.  If you wanted an excersie in frustration that was the printer to have, but I learnt a lot from that machine.

PK, I have just been lucky, right place, right time.  The people who have prints off me use them for presentation, brain storming or just to get an idea of what an injection moulded part will look and feel like in its application.  Only one client uses direct printed parts from me as end user parts, the setup cost for the intended mould was £10k plus and he can just call a print off as and when with modifications only needing CAD tweaks before the print.  We did test the end user acceptance to printed parts first and they had no problem, but itís a very bespoke product in lime green.

The banding in prints tends to be in extreme parts than my normal smaller items.  Not to forget banding is a handy visual indication to FTFP
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 07:30:41 PM
My problem is that the plastic snotters just don't suit what I/we do. Heck, maybe one day I'll just make one to win the argument...

I think that's my problem. Not that i'd be in a hurry to spend £5000 or whatever it is for a big ultimaker or a replicator or a duplicator or a binglebot, where all their budget seemed to go into getting some 'baby's first industrial design' shell made for it. But that I kinda wanted to prove a point in building my own machine but i'm still not entirely sure what that point was supposed to be. I guess just that I hate most of the designs out there for one reason or another and thought I could do better. But now i'm not so sure.

Actually i'm sure if I actually comitted to any of my shoddy designs they'd be better than a good chunk of the stuff out there, even commercially produced stuff with multiple thousand price tags.


I have 3 older Createbot Miniís.  The touch screen versions are not an improvement...  They really went to town getting the cost/quality down 8-(   Maybe they raised their game again, but looking at the review ratings I think not.  A couple of Mini Kossel printers, but they still out fox me with the complex setup every time you change the firmware, I will get the better of them. A now defunct Printrbot Metal Plus is the last on the list and being rebuilt with a newer 32bit Duet board and E3D hot end.  Some of the old printing posts mention the Mini printer.   Prior to all that I started out with a loaned Rostock Max 8bit delta.  If you wanted an excersie in frustration that was the printer to have, but I learnt a lot from that machine.

PK, I have just been lucky, right place, right time.  The people who have prints off me use them for presentation, brain storming or just to get an idea of what an injection moulded part will look and feel like in its application.  Only one client uses direct printed parts from me as end user parts, the setup cost for the intended mould was £10k plus and he can just call a print off as and when with modifications only needing CAD tweaks before the print.  We did test the end user acceptance to printed parts first and they had no problem, but itís a very bespoke product.

Looking at the rise and fall of several companies it seems to be that they all die when they decide to exchange a decent design for a scaled back design in some sort of Star Trek minifridge designed by people who only know bad videogames.

I had a good laugh at Solidoodle's goodbye message.

A few years ago Solidoodle was one of the leading manufacturers of consumer 3D printers, with 70 employees and over ten thousand units shipped. Regrettably, we stumbled on the launch of our 5th generation product, the Solidoodle Press, which fell short of our high standards for providing an outstanding consumer experience. This led to a downward spiral of declining sales and layoffs that further hindered our ability to deliver a great consumer experience.

Phrases like Consumer Experience are so insane to me, especially in this context. 

I guess it's a tricky market as the fad died out and the Chinese undercut everyone, but trying to trick people with a fancy exterior is just plain dishonest.



Also seems Windows installed but its refusing to activate for 'security reasons' and refusing to download updates. A restart might fix it but i'm done for today.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 06, 2018, 07:34:55 PM
Had they arrived on schedule, we would have had much more time for testing and inspection, and would have realized crucial cash flow much sooner.

Seriously this corporate talk cracks me up. It's the way they can't shut it off when addressing the public, like they fully believe in this language and it's message. I wonder if there are any lawyers out there that talk legaleze in casual conversations.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 06, 2018, 08:20:57 PM
I've gotta chime in...
My exactly constrained design is a 15" class machine.  The Y axis is overhung from the main Z rails.  A key technique I used is having one thing controlling each degree of freedom.  As an example, the Y axis has wheels running in grooves on the left and wheels running on FLATS on the right.  That way, the alignment of the Y rails isnt important.
That said, I found that my Y 20mm square rails sagged more than a layer under load, but repeatably.  I used mesh leveling and totally solved it.
If you have a CNN and/or a plasma cutter, my design is easy to make.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 07, 2018, 11:24:32 AM
Finally got windows update to work. On the 32 bit version it just... worked. And installed everyting, graphics and audio drivers and all. But for some reason on the 64 bit version it took alot of searching and various tedious workarounds to get it to work, including reinstalling the operating system yet again.

I also had to reinstall it again after I somehow managed to set a password I couldn't re-enter. Guess my fingers were misaligned on the keyboard in some manner while I was half asleep.


I know all this has nothing to do with 3d printers, but I haven't had a chance today to even think about them. Reinstalling an operating system once is a bit of an adventure, but after 4 times it just becomes a little more hopeless feeling. I think when I get my PC back i'll start looking harder at whats actually on the market. There's stuff like the CR-10 I believe that retails for quite alot for a machine assembled from extruded profiles, but maybe it'll look more appealing if I actually price up assembling something similar. That said I don't care much for the whole Y axis on the table design that's quite popular. Having to move a changing mass and also taking up alot more desk space than neccecary for the movement.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 07, 2018, 12:04:22 PM
Another look at gumtree and this has come up. And only this.

https://www.gumtree.com/p/printers-scanners/3d-printer-anycubic-kossel-pulley-assembled-with-auto-level-sensor-/1312934735

Not about to rush out to buy the first thing that appears, and i'm not super psyched about delta machines, but doing a quick read suggests its a RAMPS1.4 based thing. Which along with an arduino, 4 stepper controllers, and 4 of the cheapest motors on the one website I was looking at comes to just about £100. That'd also not be including a power supply or the whole extruder deal. Hot ends look easy enough to make with a lathe. So I guess that asking price isn't too riddiculous, but I still don't think it'd be Massive Savings over buying the parts. Especially since I don't think that machine itself looks very good.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: Joules on September 07, 2018, 12:08:12 PM
Simon, cast your eye over this one at some point.

https://openbuilds.com/builds/core-xy-cube.3536/

Not keen on the wheels running on extrusion, but the cheap eBay rails could be a good substitute.  An interesting starter that could have a fabricated steel shell.

Look up some YouTube reviews for that before committing (Anycubic Kossel).  Build the hotend, buy the nozzles.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 07, 2018, 01:29:06 PM
I had a look at those openbuild rails. They're an interesting idea but yeah I wasn't super psyched about them either. And not very competitive in price against other kinds of guides. Not for relatively short spans at least. Was considering making my own wheels and even ordered a few of the cheapest bearings I could find to try them out. They were incredibly tight and hard to turn.

There's a place nearby in stockton on tees, which isn't far from where I usually buy metal, called Valuframe that sells the regular aluminium profile. It's a good deal cheaper than the V slot stuff.





Also FINALLY. 64 bits this time.

(https://i.imgur.com/bR7OrYh.jpg)

That has to be the worst time i've ever had installing an operating system. I installed Windows98 on an old 90s laptop last year and that was fairly painless with easy to find drivers. I even ran pirated XP for years and that was so easy to install I was doing reformats twice a year just to keep the boot times fast.

Windows 7 used to be great...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 10, 2018, 01:33:15 AM
(https://i.imgur.com/YkwxXjS.jpg)

I found this way tricker to produce than it should've been, since it's just a bolted box. Spent a while ditching folded sheet metal ideas until I was left with just extrusions. Not really figured the gantry out but there's plenty of coreXY stuff to look at to get ideas from.

Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 10, 2018, 08:46:53 AM
A good trick: drill through your extensions and tap the center hole.  Soooo much more rigid than the standard tinker toy bits.  Corner blocks with through bolts are better than angle bits also.  This is based on actual use/comparison, BTW.
Also, I suggest some double/triple wide beams on the bottom to get a rigid base.  If you do this, the top connections are much less ctitical.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 10, 2018, 01:06:59 PM
A good trick: drill through your extensions and tap the center hole.  Soooo much more rigid than the standard tinker toy bits.  Corner blocks with through bolts are better than angle bits also.  This is based on actual use/comparison, BTW.
Also, I suggest some double/triple wide beams on the bottom to get a rigid base.  If you do this, the top connections are much less ctitical.

Sent from my SAMSUNG-SM-G891A using Tapatalk

Thanks for the tip! I was looking at using the center hole just to save on hardware, but didn't know it was stronger!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 10, 2018, 02:23:42 PM
Since this thread is worthless without pictures, I dug some up!
You can see my base using triple wide extrusions in a kind of double-barred H; this lets me bolt through without having stuff intersect.  I use the side pocket for the power supply and brain.
One shot clearly shows the wheel-on-flat system I use on the far end of the Y and Z axis.  The idea is to only constrain one thing: rotation around the other extrusion.  Another shot shows the controlling Z and Y plates; these all run in the V-groove.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 11, 2018, 05:38:53 AM
I appreciate the pictures. I also appreciate seeing a machine where the gantry moves up and down. It seems to be a rare arrangement for some reason.

I really like the look of the whole drive mechanism. Every time I look at coreXY and similar stuff it just seems overly complicated and prone to more problems than it'd solve (I get the feeling stuff like H bot and CoreXY is just trendy renaming of older plotter ideas). It's also interesting how you've refrained from joining the two vertically moving struts to make a box, but thinking about it - it does make more sense to do it that way and avoid over-constraining.

Is that machine a work in progress still or is it working?
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 11, 2018, 06:37:03 AM
Oh yeah a question i've been meaning to ask is 'whats the deal with PETg?'. From what I read a while ago it was spoken as if it was a wondermaterial. Strong as ABS but without the shrinkage and need for a heated chamber, and didn't seem too expensive either. But i'm still finding plenty of stuff that suggests people haven't given up on ABS despite that.

I do realise that for a large machine having a heated chamber would make things complicated. I've seen people struggling with cooling stepper motors but i've not heard much mention about thermal expansion, which I assume would cause issues. Especially if the whole thing heats up during the print.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 12, 2018, 12:22:05 PM
There are about a dozen of my bots out working, and mine has been banging out parts for years.  There's even instructions!

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 12, 2018, 12:26:24 PM
PETG is good stuff!  However, it doesn't glue worth a darn.  Pretty sure paint is out too.  You've got to make your part ready to use.
Just enclosing your printer improves all the thermal stuff a LOT.  That's what I do; waste heat from the bed is it.  I put the electronics at the air intake to keep them a bit cooler.  My old small printer used a light bulb and a dumb temperature switch to add a bit more heat.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 12, 2018, 01:44:32 PM
Aha that's good to know. Justifies the huge printer then!

Kind of a shame though since filler and paint was part of my plan to make some parts in the future. But from what i've heard of ABS it's a real chore for large parts.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: ddmckee54 on September 12, 2018, 02:35:25 PM
Is there an accepted definition for a "Large" 3D printed part?  If so what is it?

Don
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 12, 2018, 02:46:43 PM
Is there an accepted definition for a "Large" 3D printed part?  If so what is it?

Don

I don't think so, and it's part of the problem I had trying to find stuff to look at just going through google. Those huge novelty 3d printers and bogus grant projects suck up alot of the attention and search results.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 12, 2018, 03:42:37 PM
I'd classify "large" parts as bigger than about 6" in the longest dimension.

As for finishing large parts, it's a function of "how pretty" and "how often".  If you make an acetone vapor unit for your largest part, then you can make a big improvement quickly.  I've done that on parts up to about 6" tall; I printed a riser tube for my rice cooker and covered it with Aluminum foil tape.  There is a special epoxy resin for filling the grooves, but I haven't tried it yet.  The attached photo has a cat hole about 8" tall, mostly finished to fully smooth with a file.  Each side was probably an hour worth of filing.(https://uploads.tapatalk-cdn.com/20180912/6fd3cab68352be4460bd7450250e65f8.jpg)(https://uploads.tapatalk-cdn.com/20180912/87c70ecd742b0c2c706b67039e3c6d0f.jpg)

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 13, 2018, 04:11:42 PM
Another look at gumtree and this has come up. And only this.

https://www.gumtree.com/p/printers-scanners/3d-printer-anycubic-kossel-pulley-assembled-with-auto-level-sensor-/1312934735

Not about to rush out to buy the first thing that appears, and i'm not super psyched about delta machines, but doing a quick read suggests its a RAMPS1.4 based thing. Which along with an arduino, 4 stepper controllers, and 4 of the cheapest motors on the one website I was looking at comes to just about £100. That'd also not be including a power supply or the whole extruder deal. Hot ends look easy enough to make with a lathe. So I guess that asking price isn't too riddiculous, but I still don't think it'd be Massive Savings over buying the parts. Especially since I don't think that machine itself looks very good.

I have a half built Anycubic Kossel - linear rail version. I have swapped the hotend for a genuine E3D V6, the 12V power supply for  24V, the bed heater for a 240V SSR controlled unit and the control board for a duet (old version - not the wifi one). A lot of these parts were gathered over the years for various other projects and are being re-purposed.

It doesn't ooze quality but like most cheap Chinese kits if you upgrade the parts and assembly process judiciously, they can turn out quite good. I love watching delta and Corexy assemblies move. I find them very elegant in comparison to Cartesian assemblies, so I couldn't resist when I saw them being sold for less than £200 delivered last christmas.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 14, 2018, 05:17:19 PM
Been putting this off because I just can't settle on a design.

(https://i.imgur.com/YWsSM9s.jpg)

Went back to CoreXY since it fit into what i'd already come up with the easiest. It's a little over-built though using the 40mm extrusions. I can't help but overbuild the wrong parts. It's often said that any idiot can make anything work, but it takes a real engineer to make something that barely works. I might use 30mm extrusions in the end.

I really like the look of your machine WeldingRod, and it's clearly a superior design to what I can come up with. But i'm not sure how you'd enclose it without making its footprint huge. The area I want to fit the machine is about 600x600, and id like the build volume to be at least 350x350x500.


So assuming I continue with this design then... where would be the best place to put the Z axis screws?

(https://i.imgur.com/JcRa1eb.jpg)

In the middle seems most obvious, but I can see it tipping as the gantry moves past the center point. But at the ends seems like there'd be alot of leverage to flex stuff...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 14, 2018, 05:47:49 PM
Fully enclosed, my printer is 690x690x660 deep for a 380mm build cube.  Yeah, it's pretty big!  (https://uploads.tapatalk-cdn.com/20180914/1e5179f23a9e3846331c200931fdc516.jpg)

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 14, 2018, 05:52:38 PM
I would make choices to minimize and balance loads.  Your 3d model with the screws has good locations. 
Btw, speaking from having two screws... I highly recommend coupling them with a belt (if posdible), even if you have steppers for each.  When the power is off they can get desynchronized and tilt your z axis.  Also, watch out for backdriving the z when the power is off.  I use multiple constant force springs to counterbalance my z carriage and make it so it doesn't backdrive when it's off.  Belting helps this too, as you have to turn multiple motors to get in trouble vs only one.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 14, 2018, 08:13:49 PM
Coupling them at the bottom would be fairly simple I think, under the table. I figure it'd be a good idea to put the pulleys between bearings so it doesn't flex the screw.

Thinking about it some more, i'm going to be using cold rolled steel for the verticals. Ground rods are too expensive and at that point i'd probably do better with Chinese MGN guides. I sorta wonder how the bearings sticking would affect stuff. Maybe i'm blowing the problem out of proportion but i'm just imagining if I put the screws in the middle then the whole thing is going to be see-sawing about. I guess if that happens then I could add some struts under the table to add some more. 8 bearings! Overconstrained isn't a word i'm familiar with.


A bit ago I tried using autodesk inventor since it has alot of neat seeming features. Especially the kinematics and the deflection modelling stuff. Turns out the kinematics don't work too well for complicated mechanisms like straight-line linkages. And I find the method of modelling stuff really hard to get used to. Maybe it's a learning thing but I feel with sketchup it's really easy to move stuff about to brute force my away into a design, when with Real cad then you need a good idea of where youre going to begin with. But then I can't actually simulate deflections.

Maybe I should learn some maths.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 15, 2018, 02:22:00 PM
Exactly constrained means that a moving part on a machine has parts that locate it in X, Y, Z, Theta, Rho, and Phi.  Over constrained means that one or more of the directions and rotations have two or more parts fighting to control them. 

A common example of this is an axis running on two linear bearings.  To make this simple, I'll talk through it in terms of two ground rods with a total of four tubular linear bearings running on them and a lead screw.  Lets say X is the direction parallel to the rods.  The X direction is controlled by the lead screw; easy.  The Y and Z directions are controlled by the linear bearings.  Rotation around the X axis is controlled by the linear bearings, as are rotations around the Y and Z axes. 

There are two big over-constraints.  The first is that the pair of linear bearings on a ground rod MUST be co-axial to be able to move.  This is typically pretty easy to do, as you can often stick them on the rod and then screw them in place.  A lot of linear bearings include some facility to  provide a small rotation to self-align.

The tough one is the two ground rods.  If they are not parallel, then the motion will jam.  Getting them onto a common mounting plane helps alignment a lot, but you still have to get the two parallel (within the flex/slop of the system) to get motion to work.  We often solve this by using a flat surface to mount the ground rod ends and then doing the trick where you go to one end, tighten the mounts some, go to the other end and tighten a bit, rinse and repeat...

As for the rotations, lets think about X first.  If the table rotates around the lead screw, nothing happens (other than a little motion).  Thus, the lead screw doesn't control this rotation.  If we consider the right hand ground rod to be the master one, we can imagine rotating the table around it.  This rotation is prevented by the TWO bearings on the other ground rod; this means that its over-constrained, and that we have to do some sort of special alignment to get it to work.  Y and Z have an even higher degree of over-constraint; they each have 2 or 3 extra bearings fighting for control plus the lead screw is going to  resist rotation around Y and Z (and bind up).

If you go to a total of three linear bushings, things get quite a  bit happier.  Think of "three points define a plane".  Using a fork/slot bearing as the singleton is the best choice, or putting the singleton linear bearing IN a tight slot.  One or both bearings on a common shaft need a spherical housing (ideally something you can clamp after installation).  In a perfect system, the coupling between the lead screw and the table would have a couple of flexures so that the nut can seek its own happy spot.  Set up this way, X is only controlled by the lead screw.  Rotation about X is controlled ONLY by the fork bearing.
Y is controlled by the bearing pair (remember the fork is pointed in the Y direction).  Rotation around Y is also controlled by the bearing pair; the fork won't contribute any significant rotation resistance as its short relative to the pair.  Finally, Z is set by the three table bearings.  Rotation around Z is just like Y; the bearing pair.

After I funded the Cobblebot printer, I found out the hard way that they TOTALLY didn't understand this stuff.  They had a quadruple bearing group running in grooves on EACH of the four posts.  Thus, the darn posts had to be totally parallel for the Z to move at all!  And, the two screws had to parallel also.  Further, the motors were on the bottom, so the most critical position (starting) was the one most likely to bind up!  The Y axis had two bearing quads.  Again, requiring two linear rails to be perfectly parallel to each other.  X was the only one that would run reliably.

Sorry for the long blather!  Its a topic dear to my heart, and one that I spent a LOT of time on to get my printer working right.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: PK on September 15, 2018, 05:58:39 PM
I highly recommend coupling them with a belt (if posdible),
Good suggestion. There are other options too.
We recently noticed that our router wasn't cutting squares. It looked like the bed got a bit of a warp in it when it was moved to our new facility.

Part of the fix was to add a second home switch to Y (Y was driven by two steppers, two drives, but one set of step and direction signals) and then drive the two motors independently.
Our machine startup routine then homes both sides of the gantry, initially together, then independently.
Assuming your controller supports this, it's a fairly bulletproof way to make sure everything stays square.
 The pic shows one of the homing proxes and the other thing we did which was replace the feet with 25mm all-thread sunk into the slab so we could pull the warp out of the bed..
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 16, 2018, 08:41:30 PM
Sorry for the long blather!  Its a topic dear to my heart, and one that I spent a LOT of time on to get my printer working right.

Don't be daft. I really appreciate the write-up. I'm still a little surprised by how complicated 3d printers are. Or at least how the better ones are.

Been a little busy with some other stuff lately but i'm slowly 'assembling' your machine in CAD (sketchup!) so I can try get a better idea of how it works. And also look at making it a little narrower but a bunch taller. I figure I could replace the verticals, or at least the ones on the Z leadscrew side, with 20x40 extrusions to make them less prone to flexing if they're longer.

In the meantime I keep thinking up loads of stupid project ideas to make use of a 3d printer I don't have. Still want to do that colour mixing stuff but that's getting buried under stuff I think might be easier and more saleable.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 16, 2018, 09:06:09 PM
20x40 will definitely pay off on the main Z verticals and the two y rails.  Everywhere else it won't help much, just get in the way.  Going to less length on the y rails will help drop too.
I can easily make you dxf files for the plates corrected for those rail dimensions, if you want them.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 16, 2018, 09:39:44 PM
20x40 will definitely pay off on the main Z verticals and the two y rails.  Everywhere else it won't help much, just get in the way.  Going to less length on the y rails will help drop too.
I can easily make you dxf files for the plates corrected for those rail dimensions, if you want them.

Sent from my SAMSUNG-SM-G891A using Tapatalk

I've downloaded the dxf files from your thingiverse page and gonna try import them into sketchup at some point. I figure i'll start with the thing as close to yours as possible and then start shifting the dimensions about from there. I also feel other people might make some use from a CAD drawing, even if it's sketchup.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 18, 2018, 09:43:22 AM
(https://i.imgur.com/ttKoOKc.jpg)

This took a while. Sketchup is a pretty awful program and it's dwg impoter likes to add 100 sides to every circle, so I had to go through reducing the count on every arc and hole. Other cad programs actually treat circles as circles and just add more polygons as you zoom in but not sketchup! It annoys me that they're just sitting on a pile of patents for stuff that'd be nice in real cad programs, but sketchup is pretty much unchanged from when google bought it.

There's alot of details to add but for my own purposes I think adding every pulley and screw would be crazy. Gonna take a break then shift it around. Then actually price it out and get a fright. I've already had a look at those V-slot wheels and boy do they charge alot. There's a time i'd have machined them myself to prove a point but i'm starting to find myself short on time now. Still hoping it'll be around £300 at most though but that seems unlikely. It's easy to forget the cost of all the little things like brackets and fasteners.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 18, 2018, 02:00:13 PM
 :bugeye:  You've been busy!
Do the different types of wheel/rail interactions make more sense now?  You can imagine what happens if the two back Z rails move toward or away from the front ones; a few mm either way doesn't affect the operation at all!

I essentially treated my Cobblebot kit as a box of parts to build from, some of which kind of sucked.  The Arduino was a junky clone and the wheels were terrible.
Yeah, that stuff adds up quickly!

Oh, I should mention: I have a new design for the Z plates that has a much longer arm along the Y rails to reduce the sag.  If you re-style it to 20x40 the deflection will drop by 57% anyway.  Probably still worth having the new plate design.

I agree, Sketchup has some really cool stuff and some really terrible stuff.  Its all about the visual!  Tricky to get it to produce good STL files, but that's what I work in...  I actually worked with some folks who designed a complete cement plant in Sketchup!  OMG a big model!

Can I get that SKP model to add to the Thingiverse file?
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: kayzed1 on September 18, 2018, 02:41:56 PM
20x40 will definitely pay off on the main Z verticals and the two y rails.  Everywhere else it won't help much, just get in the way.  Going to less length on the y rails will help drop too.
I can easily make you dxf files for the plates corrected for those rail dimensions, if you want them.

Sent from my SAMSUNG-SM-G891A using Tapatalk

I've downloaded the dxf files from your thingiverse page and gonna try import them into sketchup at some point. I figure i'll start with the thing as close to yours as possible and then start shifting the dimensions about from there. I also feel other people might make some use from a CAD drawing, even if it's sketchup.

PM me your details again and i will search out that box O bits i have.
Lyn.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 18, 2018, 02:48:27 PM
If you moved the leadscrews to the middle of the Z gantry on either side, wouldn't you have a much better chance of the wheels running without binding?

Is there a reason for having the Z axis moving the hot end up rather than the build plate down? Wouldn't having the hot end moving in all three axis make it more vulnerable to vibration errors? I would think that a cast aluminium tooling plate bed dropping down with gravity and held in place by a couple of big beefy NEMA 17 motors with astrosyn damper clones and trinamic stepper drivers would make for a Z axis with minimal vibration issues. With a strong non moving top frame to float the XY gantry on, you can focus on making the gantry as light and vibration resistant as possible.

There was an interesting thread on the reprap forum a few years back on someone designing a z axis with 3 leadscrews and no slides driven by one stepper motor and pulley/ belt arrangement.

Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 18, 2018, 03:06:34 PM
I've worked with moving part printers, and Z is certainly the right axis to choose!  I agree that three axis motion on the extruder leaves you more open to vibration that 2 axis.  I was happy with that tradeoff, though.

With my design, the optimum location for the Z force is on the front two columns, as those are the ones that control rotation around the X axis.  If you put the Z drives in the center of the Y rails you have the additional problem of reversed loading; it wants to move like a see-saw, and your backlash adjustment is really critical.  With my layout the loading direction on the bearings is always the same.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 18, 2018, 03:27:34 PM
If you moved the leadscrews to the middle of the Z gantry on either side, wouldn't you have a much better chance of the wheels running without binding?

Is there a reason for having the Z axis moving the hot end up rather than the build plate down? Wouldn't having the hot end moving in all three axis make it more vulnerable to vibration errors? I would think that a cast aluminium tooling plate bed dropping down with gravity and held in place by a couple of big beefy NEMA 17 motors with astrosyn damper clones and trinamic stepper drivers would make for a Z axis with minimal vibration issues. With a strong non moving top frame to float the XY gantry on, you can focus on making the gantry as light and vibration resistant as possible.

There was an interesting thread on the reprap forum a few years back on someone designing a z axis with 3 leadscrews and no slides driven by one stepper motor and pulley/ belt arrangement.

I mentioned it earlier but my thought is that you'd want to keep the forces in a constant direction so you're only dealing with flexing. Where if it was in the middle then any time the gantry crossed over the pivot of the screw, any play in the bearings/ rollers would let it abruptly tip over.

I think i've seen that leadscrew only Z axis thread. It is pretty cool but I think it'd be dependant on fairly decent ballscrews.


:bugeye:  You've been busy!
Do the different types of wheel/rail interactions make more sense now?  You can imagine what happens if the two back Z rails move toward or away from the front ones; a few mm either way doesn't affect the operation at all!

I essentially treated my Cobblebot kit as a box of parts to build from, some of which kind of sucked.  The Arduino was a junky clone and the wheels were terrible.
Yeah, that stuff adds up quickly!

Oh, I should mention: I have a new design for the Z plates that has a much longer arm along the Y rails to reduce the sag.  If you re-style it to 20x40 the deflection will drop by 57% anyway.  Probably still worth having the new plate design.

I agree, Sketchup has some really cool stuff and some really terrible stuff.  Its all about the visual!  Tricky to get it to produce good STL files, but that's what I work in...  I actually worked with some folks who designed a complete cement plant in Sketchup!  OMG a big model!

Can I get that SKP model to add to the Thingiverse file?

Yeah they make more sense now, assuming I made the model right! From photos I was thinking there was a weird combination of rollers on flats and in grooves but it's alot simpler than it seemed.

https://drive.google.com/open?id=1dQQLoEQGdezWYBSKnv0mcwOitJjoQ6Yb Hopefully this link works. Tell me if I got it totally wrong.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 19, 2018, 01:22:16 AM
(https://i.imgur.com/JvqD6yw.jpg)

Some day I might actually start building something other than a CAD model. Price of the extusions comes to about £85, assuming they don't charge per cut. And not including delivery. If I was smart I could try mix and match the considerably cheaper regular extrusions against the V slot type depending on if they actually need the groove or not.

23 wheels are £91.91 at the UK based reseller, and £88.79 at the US site with shipping. It's alot of money for plastic wheels. I looked at these wheels right when I started thinking about 3d printers and if I remember right I priced it out machining my own and found it wasn't too much of a savings mostly from the cost of bearings, and the few cheap ones I bought to take a look at were all seized solid from tight fitting seals.

But with steel being pretty damned cheap, and the other hardware hopefully not amounting to too much, i'd like to think I could build the frame and moving parts for about £300. So I can get that done before worrying about electronics and the enclosure.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: kayzed1 on September 19, 2018, 08:03:26 PM
Plastic wheels....
Skate board bearings and a lump of round plastic and make your own :)
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 19, 2018, 08:17:36 PM
Plastic wheels....
Skate board bearings and a lump of round plastic and make your own :)

I've really thought about it. Just drilling right through and parting off, and hoping some retaining compound and a washer will be enough to stop the bearings walking out of the wheel, since that'd be alot simpler than a ledge in the middle. Then shoving that on a mandrel to cut the outside and chamfers. The 625 bearings themselves though would cost £52 from simplybearings, and as I said the cheaper ones I tried from ebay were all seized solid from the seals. Making my own at that point would probably still be cheaper, but not a huge savings and not a job I particularly want to do. I'll keep thinking about it and see if I can find that handful of bearings I bought. I bumped into them not too long ago but I forget where.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 19, 2018, 10:10:20 PM
You can use shielded bearings if you want lower friction.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 19, 2018, 10:32:15 PM
Could also use flanged bearings to save on retaining compound and perhaps make them more precise than trying to line a bearing up flush or machine an accurate step. Just ordered 10 for £3.60 to see how they are. I also ordered 10 for £2.50 but didn't notice it was from China with a lengthy delivery...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 23, 2018, 12:00:58 AM
Just placed the order for all the extrusions and corner brackets. I'm maybe jumping the gun a bit, but I figure if I sit on this thing any longer i'll never get it started - let alone finished.

Through the week i'll have a look around to get some quotes on plasma cutting for the plates, and also assemble a list of all the fasteners i'm gonna need.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 23, 2018, 10:05:57 AM
Are you in the US or UK?  There's some screws you only need 2 of, and I bought box quantities...  happy to share!  PM me your ship-to if you'd like some.
I might have a spare double pulley, gotta check...  I highly recommend the double belt with the shaft across the front.
I machined the idlers for the Z belt loop.
I need to see if that made it into the docs. (Long pause)   yes, it's in there.
Did you find the google doc instructions?  If you PM me your email address, I (think) I can give access to the common doc.
Rod

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 23, 2018, 08:03:51 PM
I'm in the UK i'm afraid, but thanks for the offer.

I am planning to machine all the parts I can handle on the lathe though, as well as czech out how deep a chamfer I can cut with delrin. For Z belt idlers i've got a whole bag of 8mm hole toothed pulleys.

I did find the build instructions. They were a big help for figuring out what half the plates are for. Although i've spotted a couple errors I made since posting the sketchup model, such as using the same motor bracket as the X axis for the Z steppers, which was reducing the volume a bit.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: PekkaNF on September 24, 2018, 05:26:38 AM
....
I am planning to machine all the parts I can handle on the lathe though, as well as czech out how deep a chamfer I can cut with delrin. ..
...

I did some batches of rope pulleys out of POM (Delrin). Check this thread, hope is inspirational.
https://madmodder.net/index.php/topic,12053.msg143327.html#msg143327

Pekka
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 24, 2018, 08:23:19 AM
It's reassuring to see that huge form tool cut without any chatter. I've heard acetal machines well but never had a reason to try it.

That's a beautiful mandrel too.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: PekkaNF on September 24, 2018, 10:05:43 AM
I was affraid that the form tool would dig itself into work, therefore "front relief" was pretty small, you almost need to push it into POM (Think I needed to adjust it just tad "under" centre line) and it does not crab. It is pretty sharp on the front (big "Back rake") to sheave off nice swarf. Thermo plastics are next to dog sh*t compared to tool steels when it comes to cutting forces. This would not work with most of the metals on these dimenssions (metals you get chatter or resort to skiving tool).


(https://littlemachineshop.com/reference/images/Toolbit.gif)
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 25, 2018, 05:42:07 AM
Nice the extrusions arrived, and all seem to be the right length. I gotta say these corner cubes look terrible though. They threw some sweets in the box too but at over £100 it'd take more than a few refreshers to impress me.

My pledge to the world is that if I ever run a tool related online shop i'll throw in a few pozidriv tips with big orders. You can never have enough of those.


Edit: First things first though, I gotta try clear some space to put it.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 25, 2018, 08:49:55 AM
If you are machining wheels, the consistency of chamfers is critical to the function.
In my design, you can put quite a few un-chamfered wheels to good use too...

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 25, 2018, 11:49:53 AM
If you are machining wheels, the consistency of chamfers is critical to the function.
In my design, you can put quite a few un-chamfered wheels to good use too...

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I just realised that earlier today. That i'd only need to chamfer... 16, i think, out of the 20-something wheels. That means I could just buy the 16 ready made wheels. That's still £45 for just the wheels themselves and not the bearings.

I'm thinking the absolutely critical dimensions are the concentricity of the outside chamfer to the inside, the chamfer being perpendicular to at least one of the sides... or the bore (flanged bearings are confusing), and then the chamfers being parallel to each other. The width and depth of the chamfers would be nice to keep accurate but I feel it's something that could maybe be adjusted to compensate for with shims and stuff.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 25, 2018, 01:03:55 PM
Yes, the chamfers need to be concentric, but the thing you really need to control is how far the chamfers fit into the linear rail.  Thus, the width and angle of the chamfers is important.  You could gauge it by pressing a scrap of rail against the wheel and measuring the wheel OD to the far side of the rail.  My model shows 42.09mm for this dimension (probably 42.0 mm in reality).  You can live with this being a bit bigger or smaller due to the eccentric adjustment, but you really want them all the same.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 25, 2018, 01:31:54 PM
I was thinking for the protrustion I could just fiddle aroud with slightly oversized bolt holes to get things square. Maybe plasma cutting is better than I give it credit for, but I was kind of assuming it'd be off by a little bit in roundness and stuff.

What has me more worried is their position along the axis, since that might try twist the plates if they're misaligned and cause weird problems.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 26, 2018, 08:46:56 AM
My plasma cut plates were so good that you could stick a bolt in a hole, let go, and it would rattle down rather than free falling.  With no cleanup on the holes! 
The plasma hole locations and edges are going to be better than +- 0.01" tolerance on absolute location.  Probable closer to +-0.002".

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 27, 2018, 06:18:06 AM
What a damn hassle. I thought i'd try exporting the files from sketchup into fusion 360 since that's the trendy new CAD program from autodesk. Sketchup's exporter barely works and has lines and circles missing, and fusion 360 is a parametric nightmare that doesn't let you easily copy, paste and move stuff around. Why is every CAD program made by idiots. I've spent all morning trying to get things to work. Different export settings results in random circles missing, and since everything wants to be parametic and goes wild if you try move stuff . Inventor was slightly better and the sketch blocks would probably help, but at a 12 gigabyte download i'm not super keen.

It's not even complicated geometry. It's just arcs and lines.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 27, 2018, 06:51:34 AM
"Yeah, @robJYZMT, that one is unfortunate.  Project should allow projection of multiple things, but today it is one-at-a-time.  I will raise this issue in our next discussion to see if this behavior can be changed, but for now, the limitation exists."

What god damn morons. Every time I search to see if a common feature is in Fusion 360, a feature that might make each thing I try feasible, I find this exact same response. 'Gee saving the file... that isn't included as of the current release. I'll bring it up at the next meeting'. Often some clown developer follows the stock response with a 'the program works perfectly and you're stupid for not wanting to click 50,000 times to project every line and arc' sort of reply.

Maybe I aught to try solidworks at some point.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 27, 2018, 08:51:45 AM
I have agree on CAD challenges.  Unfortunately, there are at least two fundamental ways to describe 3d objects.  Most expensive CAD systems are parametric; think of a list having every detail written on it.  Sketchup really works by specifing triangles and rectangles.  It also has some information on what to visually smooth.
Unfortunately, those two don't play well together.  Bleah.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 27, 2018, 03:04:51 PM
I still can't figure parametric stuff out. I mean on paper the promise of being able to adjust one dimension and the rest accommodates is quite nice, but the reality is that it ends up taking alot more setup and every feature is a new puzzle.

But what gets me the most is how hard it becomes to make big changes. The few times i've seriously tried design something in 'real' CAD i've painted myself into a corner with a bizarre history, fighting with the UI for it to activate and stay in the mode I want since the software is trying to be clever and predictive. But then loads of people use that stuff successfully so it's probably just learning all the tedious nuances.

I've been bitten hard by Autodesk owned programs in the past. Don't get me started on Maya. But it makes me hesitant to really buckle down and try figure something like fusion360 out in case it goes the same way.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: tom osselton on September 27, 2018, 03:57:57 PM
I watched a video where Larís brought in a stl file for 3D printing to do the cam on using fusion.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 27, 2018, 07:14:45 PM
I watched a video where Larís brought in a stl file for 3D printing to do the cam on using fusion.

That helps alot, thanks. Still puttering through. I've remade all the offending plates as sketches, and i'm trying to merge the sketches right now to try save myself from having to trace around the rest of them. Program just crashed though!

Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 27, 2018, 09:36:17 PM
(https://i.imgur.com/W4Icoy6.jpg)

Whoof, finally. Imported back into sketchup. Hopefully this is good enough to get plates cut. Really i've got no idea what the requirements are. The plan was to drive about today... yesterday... to a few places and get some quotes.

There's a 5mm gap between each plate, which is a little on the small side maybe. I thought i'd start low with it crammed into a 500x300mm rectangle, then maybe expand it a bit later. But I didn't think it'd be such a hassle to get it from sketchup to fusion360. That said I think i've got a better handle on fusion360 now. I still hate it!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 27, 2018, 09:53:13 PM
Um, you really need a good, watertight (ie closed profile) dxf for cutting.  The more fiddling the welders have to do, the less happy and more expensive they will be.  If schetchup will let you close it and give you a surface, then it's probably ok.

If you can tell me what you want changed its quick and reliable in old school autocad...   just z and y rails to 40mm, right?  I should be able to do it Friday, sunday for sure!

BTW, don't worry about nesting.  They've got fancy software for that!

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 27, 2018, 10:22:44 PM
I think it's closed profile. That's just how sketchup imports them, it's not a great program.

https://drive.google.com/open?id=1OeDvagCIh6nnlw7WHoQM6iVRWrF-CsP8 Here's a link. I can't tell if they're closed in fusion360 either since that likes to shade any enclosed area anyways, or even in that preview of the file.

The only changes i've made to the plates is to include 2 more for Z motor mounts and to en-widen the biggest plates by 20mm in the middle to span the 20x40 Z beams. I left the Y rails at 20x20 since I figured being a bit shorter than in the original design they'd probably be alright.

Also I was going to ask why your dxf files had the parts so far apart. I wasn't sure if it was to make use of a weird plate or something. I guess that explains it!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 28, 2018, 01:36:18 AM
Oh yeah those flanged bearings arrived today. Total trash! I didn't really expect much but I was surprised by how decent the other ones seemed once i'd pulled off the seals. Decent quality flanged bearings cost a fortune in the amounts i'd need so i'm back to thinking those stupid overpriced wheels might still be the cheapest option.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on September 28, 2018, 09:52:16 AM
 :beer:  I gave your DXF a check, and all the shapes are water tight!
A word of warning: do a careful count to make sure you have all the plates!  The set up and tear down is more expensive than the cutting for this sort of stuff.  Thus, much cheaper to get a few extras than to come out short.  I ended up with dozens of random bits after the production run of bots...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 29, 2018, 12:10:54 AM
Thanks for checking it, that's a relief to know.

I chickened out yesterday on asking places. I'm fairly certain i'm gonna make an ass of myself. There's a whole bunch of places I could ask so i'm trying to narrow the list down to a few small ones. Sign fabricators seem promising.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 29, 2018, 10:25:43 AM
Nothing better to do right now than go through the list of all the small things I need and price that out. It's my favorite part of any project where the estimated price can double. All those little things add up.

The controller boards... there's alot out there. I'm sure the smoothieboard used to be £100 but they're now £160. There's alot of them about that hover at the same kinda price, but then there's those MKS SBase boards from China for £50. A £110 savings is nothing to sneeze at.

Can't find any outright 'don't buy this!' posts about it. Just the usual 'buy cheap buy twice!' garbage. I could buy 3 of these boards for the price of an official smoothieboard.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 30, 2018, 02:56:15 AM
I find alot of people online reviewing products that got them sent for free for the review. Wonder how you get in on that...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: nrml on September 30, 2018, 03:39:12 AM
I find alot of people online reviewing products that got them sent for free for the review. Wonder how you get in on that...

I believe you start by setting up a youtube or social media channel that becomes popular and heavily subscribed. The corporate devils will come knocking at your door and then you sell them your soul for their twelve pieces of silver then spend the rest of every waking hour of your life churning out as much content as you can to keep the devils happy and your pockets lined.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on September 30, 2018, 04:48:37 AM
I find alot of people online reviewing products that got them sent for free for the review. Wonder how you get in on that...

I believe you start by setting up a youtube or social media channel that becomes popular and heavily subscribed. The corporate devils will come knocking at your door and then you sell them your soul for their twelve pieces of silver then spend the rest of every waking hour of your life churning out as much content as you can to keep the devils happy and your pockets lined.

Hahah. That's why I didn't go further with the youtube game. Seems like a weary life being at the mercy of an algorythm and there's no way you can produce Good Content on your own budget to the weekly schedule demanded for success.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 03, 2018, 01:04:48 PM
Managed to sell that fursuit head at last for a pretty decent price. Already spent most of it on this printer though.

Went about today making a fool of myself trying to find somewhere willing to cut the plates. Went with a laser cutting place in the end but they won't be ready till next week. Also in the end I just ordered all the wheels for their astonishing price instead of trying to cut them. I don't quite have the free time or enthusiasm I used to. Tomorrow i'll go to the usual place and see if they have all the fasteners in stock.

Still need to get the controller board, build plate, and figure out what i'm doing with respect to the extruder. After that I *THINK* I might have everything to get it running.

Hopefully some day i'll actually have an update worth posting!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 06, 2018, 08:02:51 PM
Plates will be ready on Thursday and then things might get interesting. But for now i've just tapped the ends of the extrusions.

But i've been looking at controller boards again and man it's frustrating. I'm not sure if I really understand the deal with open source stuff. I mean I get what it is but I don't get why people are so damned righteous about it. A Chinese guy offered them a board at 1/3rd of the price of what they already had, and then they outright rejected and sabotaged it. To me it seems like the guy selling the original board convinced 'the community' to do his work for him in fixing software issues, and then they all convinced each other that he did them a favour.

I dug up a passive aggressive slap fight between the SBase developer and the Smootheboard developer, where the SBase guy was politely explaining why he built the board the way he did but the Smootheboard guy was finding petty ways to criticize it. He came accross as a bit of a jerk. I can understand being protective about his product, but it's when he starts coming out with the 'I empowered a community to develop an amazing system, and you're just stealing THEIR hard work' stuff.

So in conclusion, i'm still confused. The Chinese boards seem good but supporting them is a taboo in the 3d printing community.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 07, 2018, 08:32:53 AM
I get good results with an Uno...  but I would pick a fancy board if I re-did it ;-)

If your cutting folks have the good hole cutting program, then the holes should work as-is.  Otherwise, you can use a step drill or a taper reamer to clean out the burrs.

The funny stepper motor shaft to belt to long shaft widget offers some quality machining time, if you need a distraction!

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 08, 2018, 03:20:36 AM
I get good results with an Uno...  but I would pick a fancy board if I re-did it ;-)

If your cutting folks have the good hole cutting program, then the holes should work as-is.  Otherwise, you can use a step drill or a taper reamer to clean out the burrs.

The funny stepper motor shaft to belt to long shaft widget offers some quality machining time, if you need a distraction!

Sent from my SAMSUNG-SM-G891A using Tapatalk

I keep getting disheartened looking at making something like the hotend, and realising that by the time I bought all the heater cartridges and other junk I might as well buy the entire assembly ready made. Delaying thinking about that rod though since i've not got any 5mm or close to 5mm bar long enough on hand. I'm also thinking about doing something with 8mm rod or pipe since i've got alot of 8mm bore pulleys.

Fussing with the build plate right now. I quite like this guy's (https://www.youtube.com/watch?v=gXUJQuNSLYw&t=126s) take. Mains power makes more sense than dealing with big power supplies dumping 12 volts into PCB traces, although those solid state relays make me nervous. Everything i've looked at though has been quite expensive so far though. Wonder if I could get away with a couple old clothes irons bolted to the bottom of an aluminium plate...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 08, 2018, 07:12:51 AM
Had plenty time to think about it while waiting for the car at the garage. The price of doing it like that Werner Berry guy is about the same as just buying a self-adhesive silicone heater. That's really become the theme of this machine.

My last idea for a Cheap Option is to perhaps clip & glue an oven heating element to the underside of the plate with flue silicone. There are thermally conductive silicone adhesives but they're relatively expensive. Something tells me it's a bad idea though...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 08, 2018, 09:54:08 AM
That's an interesting method of making a heater!  Mine runs on mains power too (120 VAC).  I have a dedicated temperature controller (and sensor) that limits the maximum temperature during heat up.  The controller board has its own thermistor screwed into the side of the bed that is able to regulate a bit below the big guy's set point.

My other 3D printer uses nichrome wire taped to the bed with fiberglass and Kapton tape (but running at 12 Volt) (second photo).  To make this sort of thing work, you need to keep the Watts per inch of wire down.  The challenge is that areas of wire that are in good thermal contact with the bed stay near bed temperature, but ones with poor contact get hot.  I had areas that got hot enough to evaporate the Teflon insulation the first time around (first photo)!   :zap: Also, terminating Nichrome wire is a PITA.  Your best bet is to either use really low Watt density and crimp on high temperature rated ends, or solder on ends.  To solder, you must sand the surface of the wire, use acid type plumbing flux and, (ideally) silver bearing solder.  Lead free plumbing solder should be ok.  The reason for the acid flux is that Nichrome has an adherent oxide layer that solder doesn't normally wet.  https://www.thingiverse.com/thing:13939

I used a siliconeheater on mine, and had Keenovo make one the right size:
https://www.ebay.com/itm/35x35cm-110V-Silicone-Heater-Cobblebot-3D-Printer-Heatbed-w-Digital-Control-Plug/281704332422?hash=item4196e2fc86:g:HB8AAOSwc1FXZgm4
You really need to get the plate flat, at least if you want the bottoms of your stuff flat.  If you use mesh bed levelling you can live with merely flat-ish as long as the shape isn't too complex.  The laziest flat surface is glass.  You definitely need a bit of thickness; 1/4" or better should work fine.

I LOVE the PEI coated bed I have; zero hassle factor!  non-zero $$, though.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 08, 2018, 10:04:34 AM
I can't recommend making nozzles, but heat breaks and heat sinks are definitely do-able and may be worth your fun time, especially if you want something a bit special.  I made a special dual-Volcano heat sink to fit my bot.
I should mention that dual nozzle are a PITA on a big printer; the tiny nozzle is always dragging on the big nozzle's work.  I have #2 raised way up to get it out of the way.  At some point I will switch over to a filament changing nozzle (basically a Y junction in the bowden tube).
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 08, 2018, 12:38:59 PM
I've been thinking about dual extrusion but yeah it just seems like a hassle. What i'd want it for is having ABS inserts on the surface of a larger PETG model, so I can glue to the ABS and hopefully reduce the shrinkage/ warping problems of an entire ABS structure. As far as I know the two materials don't adhere so it'd need to be sort of dovetailed in. But then I was thinking I might just be able to have inserts made separately and screwed/ snapped in. Or maybe just try insulating the hell out of the chamber (with water cooling for the steppers etc). Lots of ways to approach problems with this stuff! Water cooling might not be too bad to set up. Aquarium pump and hex brass drilled through with hose barbs machined on the ends, brazed to a larger plate that screws onto the rear of the steppers.


I'm starting to wonder if you could forgo the aluminium plate in between. It's used more as a heat spreader as far as I can tell. But if you painted the bottom of a big tempered glass plate black (with that oven curing glass paint) and set the nicrome wires with a bit of distance, then radiation/ convection would help spread the heat out... Maybe thread the wires around a mica sheet like on a toaster and stick some fiberglass roving underneath. And fiberglass rope to seal around the edges.

(https://i.imgur.com/jXOH9KG.jpg)

Can't find a single mica board big enough but can easily find it in half-size. I'd assume tempered glass won't explode since you'd only be heating it relatively slowly. Thing is how would you monitor the temperature of the plate...


Maybe the way you did it with tape and low voltages is the most sensible solution.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 11, 2018, 04:45:12 PM
Alright those plates arrived. I started to assemble stuff then figured I should probably paint the plates first.

The tolerance on the plates is real incredible. The bearing is a slight press fit into the hole. So paint is going to muck that up. I tried masking the holes with hot glue but it didn't really get into the corners. I still think the idea has legs though since most hot glues don't stick great to metals.
(https://i.imgur.com/emQj4YU.jpg)

After my usual excessive amount of paint leading to excessive amounts of drips and streaks, it started to rain.
(https://i.imgur.com/HV6hs5H.jpg)

I like black and gold colour schemes, but this gold paint looks kinda crappy.

Still not dry after several hours so I bought them in so they hopefully won't get covered in condensation overnight. They actually don't look so bad in these photos, and really that's all that matters!
(https://i.imgur.com/fkdU6df.jpg)

Also drilled all the holes in the extrusions.

Actually while writing this post I thought I might as well put the frame together. I was considering that id' need some big washers so the screws arent trying to 'open' the extrusions when pushing into the V groove. But I doubt i'd be putting that much torque on them.

(https://i.imgur.com/z3cF7cm.jpg)

When making stuff in CAD it's been my habit to get surprised by how big it is. But this time it seems a bit smaller than I imagined. Although it'll be larger with an enclosure.

Also it rocks on the desk if its sitting one way, but moved 90 degrees it doesn't rock at all. To me that suggests both my desk and the part aren't very flat. I'll need to investigate it, but part of why I like weldingrod's design so much is that it should be fairly forgiving of things not being entirely parallel. But I'm not so sure about what'd happen if the beams are being bowed.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 13, 2018, 12:16:15 PM
It's like Ikea furniture from hell...

(https://i.imgur.com/St90WZH.jpg)

Had to wait a day since the 2 hour dry hammerite spray paint turned out to be more like... well it's still not anywhere near fully cured but it's not so sticky now.

But without any adjustments except rotating the eccentric sleeves on the wheels it moves very freely.

I also made a coupler for the Z axis. I seem to be missing alot of drills from my set in the range of 4.5-5mm so with what I had the hole is fairly oversized, but I think some brass shim might sort that out. I need to make another but right now I also need to take a break. After that it's just the whole Y axis rod, the build plate, and then routing cables.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 13, 2018, 01:53:49 PM
Its thrilling to see another brainchild growing up!
I agree, it's hard to wait on paint!  I didn't paint any plates till version... I don't know... 6ish?

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 17, 2018, 10:37:23 AM
Its thrilling to see another brainchild growing up!
I agree, it's hard to wait on paint!  I didn't paint any plates till version... I don't know... 6ish?

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I was really in two minds about paint. I kinda like the look of bare metal, but i've had enough stuff rust now to consider paint.

This took me longer than it should've.
(https://i.imgur.com/1yC3LPd.jpg)
Got 2 of the 3 belts installed as well as the Y rod. Had to tilt the idler pulley plate up a bit to make the belt more level. Not sure what went wrong there but i'll need to think about it, but only if it causes problems.

(https://i.imgur.com/M0acJkj.jpg)
Not my best machining work. I kept making mistakes. At one point a hot chip bounced right up my nostril. Quite unpleasant!

(https://i.imgur.com/ald8ESM.jpg)
They're little jacks with a locking screw. Leather washers made from some welding gloves I bought that are so shoddily made internally that I cant get my hand inside. I figure a soft washer of some sort would be important to let the table tilt around the holes a bit.

(https://i.imgur.com/cCjZpw9.jpg)
The plate is from an old oven top. I figured the rolled edge might help support that long span better. I don't think it's entirely flat but i'm considering how to rest the glass on top. Blobs of silicone perhaps. But yeah it turns out the grid pattern on the plate is a quite precise 5mm spacing, which made laying out the holes a doddle!  All sheet stock should come with a grid printed on it. Just wish I took better care of the plate - did alot of welding and cutting on top of it.


Drove to the coast yesterday to get some filament. That's a lie, I went to get chips and because I sort of vaguely remembered I had a reason to go to the coast. Was hoping i'd remember on the way but I just couldn't till I got back. Aside from that I think I just need make a bracket fo the extruder then figure the wiring out and it should be operational. Who am I kidding something's bound to go terribly wrong!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 17, 2018, 12:23:04 PM
Looking awesome!

The Y belt pulley and idler are different dimensions; that's why it tilts.  You want the bottom side of the belt straight and the top side angled.  That way there isn't a tiny little angular error in your motion and you move back and forth.  I used belt tensioner springs on mine, BTW.  I think you can use the spring for a clothespin to do that.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 17, 2018, 12:43:27 PM
I'm not sure I understand.

This is how i've got it. With the top of the belt, where it attaches to the carriage, flat. So that the belts don't change angle as it moves.

(https://i.imgur.com/fCyh6hZ.jpg)

Clothes peg springs are a smart idea though.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 17, 2018, 12:49:33 PM
Oh couple other questions. What's the plate that hangs off the bottom of the X carriage for? It's not installed in that photo as I don't have screws long enough. But aside from possibly stiffening the wheels a bit I'm not sure if it serves a purpose. Maybe for a depth probe?

Also what is that laser cut... shape in the Z plates on your machine. I figure it's a logo of some sort but I can't tell what it is.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 17, 2018, 05:05:17 PM
D'oh!  I forgot the attachments are on top!  Yeah, you want the top level!

The bottom plate is for the z zero prox.  I'll take a pic tonight.

Mine has been cranking on a print for two days straight, after the first 36 hour print finished...  full scale, here I come!

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 17, 2018, 05:05:41 PM
Oh, my first initial in script: R.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 18, 2018, 06:14:07 PM
D'oh!  I forgot the attachments are on top!  Yeah, you want the top level!

The bottom plate is for the z zero prox.  I'll take a pic tonight.

Mine has been cranking on a print for two days straight, after the first 36 hour print finished...  full scale, here I come!

Sent from my SAMSUNG-SM-G891A using Tapatalk

I'm really dreading those multi-day prints. I was dreading them already but reading about electrical fires from all the strange high amperage Chinese boards made it worse!


Got two of them drag chains in. Of course they gotta come back out for me to have any hope of getting the cables through. I'll probably tie them to a thin steel rod and drop that through.

(https://i.imgur.com/TQkSr1d.jpg)

One to go. Just figured out where i'm gonna squeeze it. The machine is oriented as is for easier access to the interesting parts, and I figured i'd have it rotated 90 degrees in the end since that Y bar gets in the way. But I neglected to notice till now that the belts also get in the way. So as it is is probably the best orientation for easy access to the parts.

It's also interesting, to me at least, that the end pieces of this cheap drag chain is more what I anticipated - but the chain itself is made from a very tough glass filled plastic.


Finally, I need to consider how i'm going to house the electronics. I could slide a board into the upper groove on the base extrusions, and have a compartment isolated from a potential heated chamber in the future. But that won't give easy access to the electronics. And speaking of fires...

Maybe I could put a board in that groove, but also stand the whole thing on some 50mm tall stilts, then mount all the electronics to a tray that can drop and slide out.


Anyways either way, hopefully tomorrow i'll have it wired up and ready to blow some stepper drivers!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 19, 2018, 09:31:21 AM
Here's the bottom plate of the print carriage

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 19, 2018, 09:47:13 AM
Once your bot is running properly, overnight prints aren't a big deal.  You might want to add a filament run-out sensor; my last epic print took about 48 hours and spanned three rolls of filament.  If it runs out and the bed hasn't cooled, you can just stop it, pull the SD card, lower the head till it just touches the last extrusion, and delete everything from the gcode file before that layer height, then tell it to print.  That way you keep the zero point!

Cable chains are CRUCIAL to long term printing; glad to see you fitting them!  You have to be sure those dratted wires don't get caught!  Yes, straight chains are MUCH easier to thread.  Use fine stranded wire in them, BTW!

I run mine in the same orientation you are using.

I highly reccomend having a spring loaded build plate.  That way if you crash into it it can move away and maybe not booger up stuff too bad.  Ask me how I know...   https://madmodder.net/Smileys/default/confused0068.gif

My brain and power supply lives in the left corner of the base frame.  You can slip a piece of fiberglass in on top of the base cross bar and screw it down to create a cavity that is partially isolated from the hot cavity.

Mine has feet screwed into the bottom of the Z rails that raise it a bit.

I think I've posted pictures of the Z before, but here's a fresh one.  I had the X and Z cable chains as one continous chain, but connected backwards at the X/Z junction so they bent the other way.  The flip happens at the one with the "X" on the side.  The end of the Z chain is a leftover plate that I bent to shape.  I might have had a few laying around ;-)
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 19, 2018, 02:54:53 PM
I was considering a spring loaded build plate just to make adjustments easier, since I wouldn't need to trap the plate between soft washers. I decided it wasn't a good idea since I might need some hefty springs if I decide I want to produce a solid block to the machine's maximum volume, but I didn't consider the idea of the head crashing.

Got the Z axis chain installed now but not much else. I thought i'd do a quick temporary repair of the steel cold water storage tank by sticking a glob of epoxy putty on it. I figured it might be low pressure enough that i'd get away with it, but I ended up spending all day trying to drain and dry the system out enough to get some on. Might still not work but this tank needs replacing anyways. I'd be happy if it lasts a week.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 20, 2018, 04:59:14 PM
(https://i.imgur.com/7R5fGaV.jpg)

Was dreading this since I kinda knew it'd be the fiddliest part of this. What I neglected to consider though is that loaded with wires those chains weren't going to flex as easily. Especially since I got shielded cable! Had to fiddle with the Y axis chain to drop it down a bit, but now I need to add a couple more segments to get the full Y travel. Also lost about 20mm of Z height.

Still gotta extend the Z axis stepper motor cables and add a few end connectors. Should hopefully have it running tomorrow. I think I said that a couple days ago...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 20, 2018, 05:53:54 PM
Useful trick on tanks: hook a vacuum cleaner to the top port and pull some vacuum!  I've pulled a 1/2" NPT fitting out of a full hydraulic tank that way.  It was under about 2 feet of oil!  It went "glug glug" when I pulled it, hardly anything came out.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 22, 2018, 03:38:03 PM
Got it sort of wired but the X motor is... trembling. It moves but in a very loud and stuttery manner. Wonder what the cause of that could be. I guess I aught to check continuity on the cables.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 22, 2018, 03:58:19 PM
Continuity seems okay. I switched out the stepper driver and that didn't do anything. My best guess is that either the stepper motor itself is damaged or the approximately 3 meter long cable is too much for it. I'll try exchanging the motor for the extruder motor I suppose.

Edit: Motor is fine, tried hooking the Y motor to the X output and that runs fine. The problem must be with the cable. I guess I could try measuring resistances but I hope the issue isn't just the length.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: awemawson on October 22, 2018, 04:47:58 PM
3 meters shouldn't be too much Simon, I have well over that on some runs on my CNC Plasma Table. Are the motors 6 wire that you have to interlink, and maybe the linking has gone astray?
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 22, 2018, 05:20:45 PM
I wasn't sure what you meant but I did switch two of the pins inside the plug around after the first issues. I... didn't consider to check the other leads but it turns out the way it was with the middle two wires flipped was correct. I'm not sure what the first problem was. Maybe something stupid like I had the connector set over a pin.

Everything seems to work now but the Z axis. Sharing the one controller it doesn't have the torque to lift the Z axis. Is there any way to configure marlin to make use of that spare 2nd extruder controller?

Edit: Forget that last one, just found the right combo of things to google search. Also thanks for the help Andrew.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 22, 2018, 05:44:24 PM
Oops. Probing about trying to adjust the currents on the steppers. Went and Touched the wrong thing and now the display shows all the pixels on, except briefly returning to normal as it's powering off. Seems it's permanently broken but I wonder what part...

Edit: I can just make out the display at an extreme angle and turn the heater on, but none of the steppers move. I heard these things were fragile but yowch. Glad I didn't buy the stupid £160 board!

Edit again: Gonna go with the MKS Sbase 1.3 for about £50. I can feel the sunk cost fallacy starting to sink in! But it's more that setting the currents with a tiny potentiometer and calculating the whatever with the vref isn't so appealing, especially after finding out the Legends are true and those ramps boards are very fragile.

Trouble is the Sbase uses JST connectors instead of the dupont connectors on the ramps board. So I might need to crimp on new connectors or make adapters. But i've been assured by Some Guy that the dupont connectors fit anyways, but i'm not entirely convinced. Seems you wouldn't get full contact.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 22, 2018, 07:36:33 PM
I wired my z steppers in series and was happy with the result!  I think that's in the manual....

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 25, 2018, 03:01:51 PM
I wired my z steppers in series and was happy with the result!  I think that's in the manual....

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Honestly it's more the cable i'm worried about than the driver.

Alright after alot of stupid crap I finally got it working.
(https://i.imgur.com/9TwqD4f.jpg)

And alot of fiddling with the print settings. Started out with the head deciding to move up about 5mm before starting each print, but changing the initialization G code a bit stopped that. I was then massively over-extruding, then under extruding. And now i'm sort of in the ballpark with it.
(https://i.imgur.com/KegJhkc.jpg)

(https://i.imgur.com/TnOX937.jpg)

This is where i'm at now.

(https://i.imgur.com/VJWPkqq.jpg)
(usual disclaimers. looks alot worse in the photos. still not ideal)

20x20x10mm cube. I've yet to measure it. I'll grab the calipers next time I go downstairs. I think the slight wobbling is from not having a cooling fan, and the fill layers pulling the walls in a bit. Maybe getting the extrusion setting just right would further reduce that too.

I was very fortunate to have just recently met a guy online who's into this stuff. He was able to guide me through alot of the problems I was having, and I wouldn't have figured most of them out on my own. A big one was needing to install the smoothieware drivers and then, through the Windows device manager, install the drivers again (by looking for them on the list of installed drivers) on the MKS SBASE board. So it'd show up as a COM port.

I'm running Marlin 2.0 on the board. It's still in development which made it a real chore to look information up, since fixed problems got broken again, and broken stuff gets fixed on a weekly basis. So most searches show up outdated information and fixes that no longer apply. Required installing a bunch of IDEs and editors to compile the firmware. Open source guys are weird.

Also they weren't kidding about PLA smelling great. It's like golden syrup.

Edit: Dimensions are about 19.9x19.9x10.1. That's better than I expected without any adjustments, but who knows how it holds over a larger piece. I'll do some more tests tomorrow, like the classic retraction pillars and just a big flat square or grid. I also need to measure skew on parts.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 25, 2018, 07:18:40 PM
 :nrocks:
Congratulations!  I'm totally amazed that you got a good print with that few ugly ones!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: chipenter on October 26, 2018, 02:19:56 AM
I agree about Marlin settings I am running Marlin 16-12 for my mill , and some of the setting don't make sense like turning off the end stops except for homing !
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: ddmckee54 on October 26, 2018, 03:26:17 PM
S.Heslop:

As long as you have the 2.54mm pitch JST connector, and that pitch is all that I've seen on my printer or the other "stuff" that I've worked on, then the DuPont connector will fit the pin spacing.  You just don't have anything other than the friction between the sockets and the pins to hold the connector on, so the connector could vibrate loose.

Long term, I'd get the new connectors and eliminate the additional failure point of an adapter.  Short term while you're in the "I just want to see it run" mode, the DuPont connectors will work just fine.

Don
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: awemawson on October 26, 2018, 05:30:11 PM
A blob of hot melt glue works wonders, and if not too extensive can be easily removed

Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 26, 2018, 08:58:45 PM
:nrocks:
Congratulations!  I'm totally amazed that you got a good print with that few ugly ones!

Same here! It'd have been even better if I remembered to set the steps per mm on the extruder.

A blob of hot melt glue works wonders, and if not too extensive can be easily removed

That's smart. I was wondering what'd happen with the connectors since I want this board mounted upside down.


Still considering what to do for an enclosure.

(https://i.imgur.com/sXVBCra.jpg)

Something like this is similar to what i've done in the past, and i'd have half the materials. Plywood is appealing since you can easily screw stuff into it. The grey rectangle is the laptop since I think it'd be convenient to run the machine from that.

There's alot of talk about fire hazards so I was hesistant about plywood, but on closer inspections alot of it seems to be the result of crappy machines. It turns out they're disabling safety features like thermal runaway checks to save on program memory in the firmware, so they can use cheaper electronics. But it's still something i'm thinking about.

Also looking at commonly available building materials it seems like cement backer board is the only thing that's truly fire proof, but I can't imagine the dust being healthy for me or the machine, and sticking something like vinyl on it would defeat the point. There's glass too but I don't really want such large panels hanging about, especially on a machine that might get a little warm.

As for insulation - I was in the loft when trying to sort that water tank leak and found there's a few unopened rolls of rockwool up there. I could use staples to trap that behind some woven glass roving, to reduce the combustible stuff. The plywood would probably be enough but i'd also like to try insulate sound.


Oh yeah I also did the two pillars stringing test to check the retraction. Default settings seem fine with no stringing but one of the corners got a bit wobbly. I feel a part cooling fan might help with that.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 26, 2018, 10:55:42 PM
I used polycarbonate for mine.
I wouldn't insulate; you don't want to get too hot.
I would make at least one panel transparent so you can check up on the motion.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 27, 2018, 04:17:53 AM
Setting this off on a 3 hour run to see how it copes. When levelling the bed and moving the gantry around though the stepper motors seemed alot stiffer than they were. Are the bearings failing already?

Edit: Ah it turns out it's because they're plugged into the board, and it must be sending the current back into other windings. I was worried something was failing already!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 27, 2018, 11:30:27 AM
You DID do mesh leveling, right?
3x3 is plenty, but its important!

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on October 27, 2018, 12:33:46 PM
I've been doing it manually! Honestly i'm not sure how levelling works without a probe, but one of them BLtouches are on the list.

Did a big run today to check out how it handles 'real' features. Was having trouble with layers shifting though. The first 2 attempts were aborted since it was real terrible, and this is after unplugging the Y axis home switch once it'd homed at the start.

(https://i.imgur.com/nweTij8.jpg)
The right hand side here is supposed to be a ( shape, but the holes are obviously shifted.

(https://i.imgur.com/aV5fT2D.jpg)
This should be straight.

(https://i.imgur.com/gkhFS0t.jpg)
Here it is assembled. I adjusted the steps per MM a bit more after some measurements of the failed runs and it's all pretty damn precise now. More than i'd expected.

(https://i.imgur.com/TvgsHLC.jpg)
And this is what it's supposed to look like. It's more of a mock-up than anything final. It's also nice to do some actual Rapid Prototyping and see the general size of it, as well as what features clearly aren't going to work.


Anyways the layers shifting. I think that could be from interference but I still got some even when it was unplugged. But that again could be from... weird electronics. I'm no expert but I know there's some stuff about pull-up resistors and stuff, which I believe are built into those mech endstops. I should really try ground the cable and see what happens. It's odd though that the X axis has no problems at all despite being a longer and unshielded cable, although I did twist the wires.

Also I believe i'm still under-extruding. I should measure the steps per MM of the extruder as well and calibrate that.

Oh and the progressive infill setting does a great job at making the top layers flat.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 27, 2018, 04:59:05 PM
I screw a small dial indicator on my carriage, with an extension.  At each position I go down until the dial stops moving, go up, then down to the last click that moves the dial.  What's happening is the nozzle touches down and then the drive system starts to flex.  It works really well.
Then, you save those parameters, and you are good for months.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on October 27, 2018, 05:01:11 PM
On the steps per mm, put a thermostat on the filament, measure the distance from the stat to the printer, then extrude some distance.  Measure, and fix your steps per mm.  Recheck afterwards.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on November 01, 2018, 03:56:52 PM
Sorry, stupid spell check doesnt speak mad modder!
Hemostat!  Super useful workshop tool!

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 01, 2018, 05:23:14 PM
I've calibrated the extruder... extrusion better now. Still having trouble with shifted layers on the Y though. Set the accelearation and jerk extremely low and problems continued. Still running tests.

Shielding the endstop cable too and seeing if that makes a difference but I doubt that's the issue. I'd expect a different look to shifted layers than just a slight... wobble. It makes sense to me that being on the Y axis it'll be due to its weight. Everything moves freely, belts seem tensioned fine, pulleys aren't slipping. But even with accelaration and jerk way down plus a slow printing speed all it did was make the quality way worse. The shifting is also random but in small amounts, so it's hard to tell if any changes are a real improvement or not. Current is as high as I dare for the built in controllers and motors (1.4 amps).

My last guess is that the poor quality infill, a problem i've not fixed (this current test with the better extrusion calibration might work better, I was massively under-extruding it seems), does raise up enough that I hear it clicking as the head catches them occasionally, which could be what's losing steps.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 02, 2018, 04:57:32 PM
Slowed to an absolute crawl and it's still leaning. Added a capacitor accross the ground and signal of the endstop switch and that hasn't made a difference. Even probed it with the oscilloscope and i'm not seeing any obvious noise. They don't always lean in the same direction.

Maybe I could try a program different to Cura.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on November 04, 2018, 03:54:24 PM
Please post photos!  I've made lots of bad parts!
Pick something simple, like a tall rectangular block to start with.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: BillTodd on November 05, 2018, 05:25:56 AM
Watching carefully here, as im also embarking on a 3d print exploration...

re: layer drift,  might be worth checking tightness of drive pullies - mine came loose after a few hours work.

Also, are you running the steppers too fast?   your axis might be losing steps on fast moves.

Bill
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 05, 2018, 08:53:34 AM
Watching carefully here, as im also embarking on a 3d print exploration...

re: layer drift,  might be worth checking tightness of drive pullies - mine came loose after a few hours work.

Also, are you running the steppers too fast?   your axis might be losing steps on fast moves.

Bill

I've really gone through the whole checklist of things. Next paragraph is a big block of stuff I can remember trying.

Made a new simpler model, grounded the cable shields, put capacitors between the endstop signal and ground, probed about with the oscilloscope to see if I can spot any obvious interference, ran it super slow, ran it super fast and every speed in between, set the jerks low and high, accelaration too, got stuff tuned in so curling infill wasn't bonking into the head, made sure every nut and screw is tight along with putting lines on the shafts and pulleys to see if they slip, adjusted the belts, switched around the X and Y connectors to see if a controller is faulty, ran an indicator up the Z axis rails to make sure the screws werent pulling it about, set motor currents high and low and everything in between, made sure things moved freely and easily, tried other slicer programs... probably more i'm forgetting but you get the point.

I just completed an absurdly slow run on a new test object, and it's still wobbly.

(https://i.imgur.com/vRNCMR7.jpg)
The one on the left is the new one and the others are randomly selected from my now vast collection. The X axis direction is perfect.

So a pattern i'm noticing that isn't super clear is that it starts to shift in a sort of bulge outwards right before the top. Wonder if it's related to the progressive infill setting.

I also set up a dial indicator on the Y axis gantry, so when I jog it back and forth it should reset to 0. And it did for a few turns sending it back and forth 100mm, checking the indicator every few moves back and forth. It stayed at 0 for a while then moved a couple graduations away, then a couple more. And then back to 0. A full step is about half the dial - it's one of those lever type indicators that are way too sensitive and I don't trust the actual numbers, but it's all i've got.

So i'm not sure if that's from losing steps or if it could just be from how the belt sits on the pulley or something. Can you lose microsteps? Also I doubt jogging it back and forth a bunch of times is enough to really test if or how it's losing steps.

I've ordered a new stepper motor cable for the Y axis. Perhaps there's some intermittant short or something and at £1 it's probably worth a check.

Also I'll probably post this problem on a 3d printing specific forum and see what happens. I just want to make sure I get the uh obvious stuff out of the way first.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: BillTodd on November 05, 2018, 09:04:12 AM
Quote
Can you lose microsteps?

Micro steps are only a sort of 'fudge' between steps they make the motor run smoother but have no defined position.

That said I do not think that is your problem.

It does appear to be worse (or only ) related to one axis .

[edit] One thought (looking at pics) : the head is mounted by two bolts (height adjust?), could it be wobbling between the two ??
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 05, 2018, 09:28:52 AM
Quote
Can you lose microsteps?

Micro steps are only a sort of 'fudge' between steps they make the motor run smoother but have no defined position.

That said I do not think that is your problem.

It does appear to be worse (or only ) related to one axis .

[edit] One thought (looking at pics) : the head is mounted by two bolts (height adjust?), could it be wobbling between the two ??

Oh yeah that's one of the things I checked. It seems fairly ridgid but I should probably put the indicator on it to see for sure. Right now though i'm making that exact same test piece again but rotated 90 degrees to see if it's more to do with the geometry or some slicer settings. I already did a test like this on the more complicated part, but i'm feeling the taller part makes it alot easier to see what's happening. The pattern being seemingly random too also makes it hard to really gleam anything meaningful since one run might randomly look fairly good if it's relatively short.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: BillTodd on November 05, 2018, 12:35:21 PM
 Tall part.. is it rocking ???
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 05, 2018, 01:00:27 PM
Oh yeah WeldingRod, what speeds do you generally run your stuff at? I thought I had it for a bit with even lower speeds since this part looked very even from the front. But it turns out it's just a relatively even lean in the Y.

The part rotated 90 degrees turned out well so I was wondering if maybe it was the slightly faster travel speed as it scoots accross the whole part long ways. So I tried turning the speeds down even more. But i'm also starting to think i'm running on bad info as to what counts as a 'reasonable speed' (40mm/s). Running it at 30mm/s now but I've had the accelaration riddiculously slow previously where it probably never broke 20mm/s. Hesitant to quote the numbers in case it's real obvious that's my problem, but dang it feels slow.

Also the change of direction in the infill felt somewhat violent so tomorrow i'll try running it even slower on the infill. It's getting a bit late now and I don't want to trap myself into over 2 hours of waiting for the machine.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 05, 2018, 01:04:04 PM
Tall part.. is it rocking ???

I checked that too. It's only 20mm tall but with a brim and good adhesion from what I can tell. But the lines are appearing in the long direction. It's 115mm long and 15 wide.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on November 06, 2018, 01:50:02 PM
My Simplify3d speed settings for 1.2mm nozzle:
Default printing speed 2500 mm/min
Outline underspeed 50%
Solid infill underspeed 30%
Support structure underspeed 50%
X/y axis movement speed 4800 mm/min
Z axis speed 1000mm/min

For 0.4mm nozzle (which I haven't run in a long time):
Default printing speed 3600 mm/min
Outline underspeed 50%
Solid infill underspeed 80%
Support structure underspeed 80%
X/y axis movement speed 4800 mm/min
Z axis speed 1000mm/min

I will have to get acceleration and jerk off the machine tonight.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on November 06, 2018, 01:51:51 PM
Can you try printing a single wall square tube, say 30mm on a side, at least 50mm tall?
You may want to try both vase mode and regular.
This takes out some of the factors like infill...

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 07, 2018, 10:35:51 AM
Switched the X and Y again to try it once more. And with this taller part it's clearly a problem with the driver since it's now wobbly in the X direction. I guess I should see if they'll exchange the board. And failing that i'll have a look at external driver boards.

Edit: I'm a little peeved but also relieved to know what it is now. I should've caught it earlier but I ruled it out after a test. Because the layers are randomly shifted that one test I did must've had the planets align and most of the layers turn out fairly in-line. This time it's way more blatant.

They accepted the return so i'll send it off tomorrow. But woof what a hassle. Second controller to go bad even if the first one was my fault.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: hanermo on November 07, 2018, 04:59:28 PM
Excellent thread.

Does anyone know of great uses for 3d printed stuff ?
Commercial ?
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 08, 2018, 12:37:45 AM
Excellent thread.

Does anyone know of great uses for 3d printed stuff ?
Commercial ?

I still think a milling machine will take you further than a 3d printer will for actual engineered parts. Or even with wood you could produce stronger parts quicker. And for artistic stuff the FDM style of 3d printer is kinda ugly and requires alot of finishing, where more traditional sculpting might work better in most cases. But as far as I know though these machines have been around since the 70s for rapid prototyping in commercial use. But I think other methods (SLS?) are more popular for that now.

I might've mentioned it already, but what I want the machine for is making more of those goofy fursuit masks. I've made a few in the more traditional way - sculpting clay/ plasticine and making a silicone mould from that. But storing them takes up alot of space, you're limited to the base shape you started with, and it's hard to really visualise the final look since the fur and other stuff will increase the size. Plus the urethane is hard to adhere to and attaching 'hard points' and features to them requires alot of fettling to make them fit. It feels very bodged and I was hesitant to sell the one I did because of it.

So for this one very specific job I think 3d printers are probably the ideal machine. Without being locked to a mould it'll be easier to iterate the 3d model to fix shortcomings, or to sculpt it to various shapes. Or even scale it to fit different heads. And it should be easier to design more complex and elaborate features.


Er all that said though, i'm sure i'll find other uses for this machine once it's running. But I've gotta be careful to not get carried away with it. Like I was thinking earlier about clips to hold the power supply under the machine, and how I'd best 3d print them. Before realising it'd be a 5 minute plywood job on the bandsaw and drill press. One of the first times I ever saw one of these machines being used for something, in a video, had the guy 3d printing a square stick.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: BillTodd on November 08, 2018, 03:35:40 AM
Excellent thread.

Does anyone know of great uses for 3d printed stuff ?
Commercial ?

Well the break through is starting to happen in the aircraft world. Titanium is expensive and a sod to machine* , so 3d printing titanium parts prior to machining (like castings) instead of machining from stock,  saves a huge amount of time and money . There are now many machinery maker adding  laser sintering  into their cnc workstations

Printing is also having an impact on the design of parts. The use of "organic" designs that would be difficult or impossible to machine allow parts to me made lighter without loss of strength ( imagine a simple right angle bracket , replaced by a 3d structure that has finger-like supports only where needed).

Bill


* The motorsport division of the firm I work for make parts for the Redbull F1  cars , one design of brake disc carrier (imagine a thing the shape and size of a soup bowl but with more holes than metal) was taking 80 hours to machine and 90%+ of the material was thrown away.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: AdeV on November 08, 2018, 04:23:03 PM
Bill,

I went to the Racing Car show at the Birmingham NEC (that's Birmingham UK... not AL) a few years back, and got talking to a company that made laser sintering 3D printers. At the time, they could be ordered for titanium or aluminium (I'm not sure if the same machine would do both?). The machines were quite reasonably priced, I thought - around £10,000 or (at the time) about $16,000. The titanium powder to fill it, however... well, it was considerably more than the machine!

I'd love to get hold of one myself; I think it could pay its way back in the motorsport industry in very little time...
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 09, 2018, 11:26:11 AM
Only £10,000? Does that include the laser?
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: AdeV on November 10, 2018, 05:22:31 AM
Only £10,000? Does that include the laser?

I've been thinking about it... I  may be out by a factor of 10.... it was a few years ago!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 17, 2018, 12:53:10 PM
(https://i.imgur.com/avbVVkr.jpg)

Been up to this the last few days. It's relatively simple but it being so large made it a chore. It's not entirely square but it's close enough. Just need the plexiglass to finish it but i'll probably put the machine in first just to make sure there's clearance for all the moving parts. Little worried the hinges and catches might get in the way - it's a little on the small side just so I could get it all out of one sheet of plywood. 12mm plywood was also a poor choice as it's a little on the flexible side too. I'll probably need a handle so I can lift the door up into the top catch. Toggles would've been the better choice, and I might have to go that way if things interfere. Some bracing might also help, especially on the door, but i'll need to see where I could fit it.

So for the controller board. I was all set to buy the Duet Wifi at £120, but it turns out they don't include VAT on their website. Or shipping. So it went up to £150, and now i'm back to thinking if it's worth giving the MKS Sbase another shot. I've had a look at the setup procedure for the Duet and it's as complicated and stupid as any other board. What's wrong with 3d printing people... Either way i've ran out of time to mess about with this stuff so i'll possibly take a break once it's in the enclosure.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 18, 2018, 07:28:48 AM
Whoa nelly. Turns out that hump in the middle made it impossible to fit without partially disassembling the machine.

(https://i.imgur.com/KFLTSKE.jpg)

I remember I realised that when I was first drawing the box up - I made it extra tall so I could get it in. But when trying to fit the panels into a single plywood sheet I forgot all about that.

(https://i.imgur.com/gbRvUjM.jpg)
This is where the laptop will go. It turns out laptops count as a 'horizontal surface', and like any horizontal surface it collects clutter. This is more of a storage solution than anything else!

(https://i.imgur.com/lKBiuOD.jpg)
Also as feared the catches interfere with the drag chain. Still thinking what to do. The obvious thing would be to move them to the top and bottom but they're here to help keep the front flat for the sake of sealing the box. The hinges just clear on the right hand side so I can't move the whole thing further right, and I can't move the chain any further back. Plus the chain is flush against the side. No room to brace the door flat there internally... So I guess I might have to go with an external toggle or maybe a threaded insert in the side and a screw to pull the door in.

Oh yeah also gotta make some taller feet so there's clearance for airflow.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: AdeV on November 18, 2018, 08:04:00 AM
Just thinking out loud here: Could you adapt the bracket that's mounting the catch so the screws go backwards instead of sideways; then rout a notch out of the side wall and screw the bracket into the back of the notch, such that the rollers are in the same position, but now moved out of the way? Admittedly, it's not going to win any beauty contests, but it would be the quickest solution.

Another option would be some kind of lever latch, again with the pin embedded in the side wall & a slot for the tongue to engage. Either make some kind of spring-loaded push-pull tongue (triangular shaped, so it could force its way past the pin), or just a hook shape, and have a handle on the front to open it. Quite a bit of fiddly mechanical workings out to do for that one though... but it would look tidy.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on November 18, 2018, 08:35:13 AM
I just realised I could totally brace it on the front with a big beefy and tall handle. Then I can just stick with latches on the top and bottom, out of the way of the chain.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: AdeV on November 18, 2018, 09:16:37 AM
Excellent idea - it'll look cool too!
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on November 19, 2018, 05:08:55 PM
Nice enclosure!
I used a pair of.magnets to latch mine.  You could rout them in to the two surfaces.

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Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on December 20, 2018, 06:39:30 AM
I've been a bit busy lately, but a month later I got a bit more done with this. I was able to remove the two interfering latches and it latches fine now with just the one, since the weather strip has compressed down a bit and is staying compressed. Door still isn't flat so i'll add the handle... eventually.

Went with a Duet Wifi and it seems fairly decent. Still needs some more setting up and tuning.

Produced an enclosure that's someone else's design. I was stumped for a bit since it was massively under-extruding when exported from cura, but it turns out it's a known bug with the older version when exporting gcode.
(https://i.imgur.com/RXk4nOc.jpg)
Took about 40 hours I think. I paused the thing in the middle when going out for a bit so it reset the timer. I think it added a huge amount of time since it was slowly filling in the tiny gap between the inner and outer walls on the... walls. But once I figured that out I wasn't about to restart it. There were also a few unusual errors with it underextruding on only a couple places, and cylindrical features turned out a bit porous. But It should be good enough for this enclosure.

(https://i.imgur.com/3RGK3CD.jpg)

A new infill pattern comes with the Latest Cura. It's kinda neat looking and supposedly more durable and efficient


Anyways my review of the duet wifi so far: It's got a few features I really like. When first starting you can adjust the Z offset as it's running to get it just right. And you can adjust the extrusion multipliers and temperatures on the fly too, as well as other things like fan speeds. It also turns out that it runs from the SD card and you're just uploading the gcode files over wifi (via a web browser interface). It kinda hides alot of features behind gcodes you can send through a console though, which is something i'm learning as I need to. But I still think they could've just made it a bunch of UI elements instead.

I also really appreciate that they have an actual setup wizard, even if their documentation is a bit vague and patchy.

I kinda assumed it'd need to be tethered to a PC as it ran, so finding out it doesn't means the whole space for the laptop is a little redundant. Maybe some day i'll buy their stupid overpriced display to fill the space.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: jiihoo on December 21, 2018, 09:19:58 AM
Your printer seems to print quite nicely!

It is a good idea to try a few of the infill options on Cura or whatever slicer you use before committing to the print. The new infill, gyroid, sounds nice and good and symmetrical strength in all directions and whatnot, but it is not fast to print. I was pondering a 12-hour print the other evening, well it would have been a 12-hour print with gyroid and 10.5 hours with the traditional grid infill. I chose grid because there was nothing to be gained by using gyroid in that particular part. I think I am saving using gyroid for parts where I think it will do some good and stick with grid as the default choice.

If printing something with flex or semiflex filaments, then I believe gyroid infill would be a good choice (probably the best choice there).

Speaking of flex, have you tried any flexible or semi-flexible filaments yet? They open up new possibilities for 3D printing. If you want to do an easy foray into somewhat flexible filaments, try Polyflex from Polymaker. It is semiflex. The reason to try that over any others is that it behaves quite like PLA when printing and should be within the capabilities of most any 3D printer. Start from normal PLA settings and just increase the head temperature a little (to 225-230C); you may not even need to slow down if you are not using warp9 speeds with PLA (40 mm/s would be a fairly safe speed with Polyflex; go down to 30 mm/s if you experience extruding issues but people have reported even 50 mm/s working with it; if you have other problems disable or reduce retraction while working out the issues). Polyflex is generally considered the easiest of the semi-flex filaments to print and works good in both direct extruder and Boyden extruder designs providing the feed path offers reasonable support for the filament (no big gaps where the filament could escape to the side...).

The more flexible filaments can be "somewhat" difficult to print. No personal experience there, but Polyflex definitely works as it should as long as you do your part and keep the spool of filament dry!

PETG might be an interesting option too. It is less hard and less brittle than PLA and reasonably easy to print (i.e. you will only pull out half of your hair before you get it printing good). It is also printable indoors, i.e. no nasty smells ala ABS. I had trouble getting good adhesion of the first layer to the bed, but increasing the bed temperature to 83 for first and 80 for rest of the layers and starting to use a 3D printing adhesive (Magigoo in my  case) solved it. I know many people have managed with lower bed temperatures but for me they didn't work. Also no or very little fan speed is good.

Cheers,

Jari
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: S. Heslop on December 21, 2018, 06:56:17 PM
I didn't know there were flexible/ semi-flexible materials that printed through a bowden. I've got a bowden cable on this machine, and a somewhat long one since it's so tall.

PETG is something I want to try, but i'll have to figure out a heated build plate first. And that's probably a ways away. I'm actually kind of surprised by PLA, all the stuff i'd read made it sound like it'd be extremely brittle. Maybe it's the variety I bought, which isn't anything special as far as I know. Velleman from a nearby electronic component place. I'm going to run some tests at some point when I have time. By tests I mean dropping large objects down the stairs.

I think with my intended application though ABS would be the ideal choice. It's part of why I went with a hopefully mostly sealed enclosure. But again I need that heated platform before I can give that a shot and see how well sealed it really is.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: awemawson on December 21, 2018, 07:02:33 PM
I managed to print with Pet-G on my Cetus-3D before my heated bed arrived and it went OK. I was only printing small things though.
Title: Re: Sheet Metal Brake and 3d Printer.
Post by: WeldingRod on December 21, 2018, 10:13:42 PM
I've printed with PETG on welding rod bot #1.  Very nice prints, flexible and sturdy.
Nothing reasonable glues it, though.

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