Author Topic: 3D printing  (Read 36698 times)

Offline picclock

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Re: 3D printing
« Reply #50 on: August 12, 2015, 12:37:53 PM »
Hi PeterF

The printer has 3 main types of board and an LCD display/sdcard interface. The Arduino card I got from http://www.ebay.co.uk/itm/171827024551 for 7-99 (you could possibly do better on this). This then has a Ramps 1.4 card which I got from http://www.ebay.co.uk/itm/151768808587 for 3.78. The Ramps 4 card has 5 plug in Stepper drivers which I got from  http://www.ebay.co.uk/itm/141672347924 @ 1.32 each (I ordered 6). It also has the thermistor inputs and the head/bed heater control outputs. The Arduino board is also attached to the graphic display and SD card adapter which I got from http://www.ebay.co.uk/itm/141679594646 for 6.48. I also ordered some thermistors and optical end stops for a few pounds.

So far I don't think I have spent much for what I have ordered. Time will tell when it eventually arrives. Am more concerned about drilling the granite countertop than the electronics.

Best Regards

picclock
 
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline awemawson

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Re: 3D printing
« Reply #51 on: August 12, 2015, 12:58:46 PM »
It's amazing what you can buy for remarkably little money in the way of pre-assembled electronics these days. At those prices you couldn't buy the components !
Andrew Mawson
East Sussex

Offline PeterE

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Re: 3D printing
« Reply #52 on: August 13, 2015, 12:05:38 PM »
Hi picclock,

Some very nice links there, thanks a lot. Have to investigate a bit closer but I don't think I can get so much better deals than those.

When it comes to drill the granite.
I had to get rid of a very slightly broken corner on one of the benchtop granite "boards" in our kitchen. What worked the best was my diamond file with which a gentle hand quickly fixed the problems.

That said, I guess that diamond-coated drill bits might be a good way forward. As an example of types and prices, the link below lists some easily available ones at reasonable cost.

http://www.arceurotrade.co.uk/Catalogue/Diamond-Tools/Diamond-Drills

Slow going (light pressure) and maybe water cooling should do the trick.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline picclock

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Re: 3D printing
« Reply #53 on: August 13, 2015, 02:10:11 PM »
Hi PeterE

I have ordered a couple of 6mm diamond drills from flea bay. I figure I will have to drill about a dozen or so holes hence the spare. I plan to do the drilling on my mill so that all is controllable with minimal lateral forces. Its just something I've never done before - hence the trepidation. I will make aluminium holders for the y rails and do away with the studding altogether. The gantry will be mounted with side plated directly to the granite so the relationship between the two will be v good. I have ordered up a cheapy set of ABS printed plastic parts for $20 (around 13), so that will be enough to get me started to print the final pieces for the machine. Am also getting on well with designspark - done cones now  :med:. Will have to cheat on text though and import it from sketchup when needed. Looking forward to when all the parts arrive and I can do a build. Will start a thread with piccys in Project logs, though there are a lot of build threads for this type of machine on the internet, so I'm not sure how useful it will be.

Best Regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline PeterE

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Re: 3D printing
« Reply #54 on: August 13, 2015, 03:37:18 PM »
Hi picclock,

Will be interesting to hear/read about the granite drilling exercise when time comes.

Your thoughts and mental sketches for the "frame" sound very ridgid and it will be interesting to see the build.

One thing that occurred to me today was that the four printed corner pieces making up the Y axis have no means to secure them to a bed surface. No "ears" or any other means to fit a screw. Think I am going to make some add-on ears from a couple of alu bits. Just haven't worked out the final solution yet. But that should give even more rigidity and stability to the whole setup.


BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline picclock

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Re: 3D printing
« Reply #55 on: August 14, 2015, 02:54:07 AM »
Hi PeterE

The whole issue with the base in this design is a major one. As you so rightly point out, the y frame and gantry are all supposed to rest on a flat surface in order to achieve any sort of accuracy. Fixing them to something flat is the only way to consistency and rigidity. Once that is sorted the only other thing is the flexing of the gantry in the y plane which can be sorted by two side plates. These can also be used to ensure a true 90 degree angle for the gantry. As to the rest I will find out soon  :scratch:

Best Regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline Swarfing

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Re: 3D printing
« Reply #56 on: August 14, 2015, 05:21:56 AM »
I did not find the base to be a real problem. The longitudinal threaded roads fix to the cross member by aposing bolts which is very rigid. Also if you look at pics of the machine the back cross threaded rod fixes into slots on the side bracing pieces. words of thought here as I found the measurements did not compute for me and the rods ended up being short so measure this bit carefully before cutting. I screwed from the bottom of the base up through to the cross member and side braces. I managed to get him to send me a pic to show you more detail. Hope that helps.
Once in hole stop digging.

Offline efrench

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Re: 3D printing
« Reply #57 on: August 15, 2015, 03:26:03 AM »
I used masonry bits to drill through a 3" thick granite surface plate.  I did it outside with a hand drill and the garden hose keeping it wet.  You definitely don't want to be breathing the dust.

I made through holes, but the best way to do it is to epoxy steel inserts into the holes and keep them level with the top using magnets.

IIRC, the Prusa i3 attaches the print bed at four points.  If this is so, it should be modified to use only three points similar to the way a surface plate is supported.

Offline picclock

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Re: 3D printing
« Reply #58 on: August 15, 2015, 02:35:39 PM »
Hi EFrench

I thought to do it much the way you said, except I was going to drill 15mm deep holes,  fit a nylon bolt into a steel M6 spacer with a nut and washer on top. Then epoxy spacer into hole using washer as depth stop. Loosen nut and washer before finally set off and remove any partially set epoxy, then finally remove nylon bolt. I figured it would be a lot easier that drilling 30mm of granite.

Print bed is not nice in the original design. Problem is that its not stiff and flexes with temperature as it warms up. Will try it with the original, cos its dead cheap and quick, but will likely replace with glass and heater pad, shame the cost is so high atm..

I seem to remember at one time you could get stick on heating elements for rear windscreens - something like that on a printer bed glass would resolve the issues of warping altogether (100C on a windscreen is a bit much I suppose  :lol: ).

Best Regards

picclock
« Last Edit: August 15, 2015, 03:31:50 PM by picclock »
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline PeterE

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Re: 3D printing
« Reply #59 on: August 15, 2015, 04:32:01 PM »
Swarfing,
The picture attached shows a lot but not all of your setup.

   I notice that you placed the bracing triangles in line with the central opening and not in line with the outer sides of the upright. Any particular reason why?

   The Y axis motion parts are as you say connected to the upright using the two Y axis all-threads and nuts, and I can also see that you have made the upright with double thickness compared with the drawings I have seen - much along my thoughts as well, but did that create the "too short allthread problem"? Menaning that it affected the length for housing the Arduino below the allthreads at the back?

   You mention that you have secured the upright to the base plate using screws from below, but have you also secured the Y axis motion end parts as well or is the only connection through the pinching in the upright slots?


efrench,
Yes you remeber correctly. The design is to have the print bed secured at the four corners and I guess that the clipped-on glass plate is used to prevent/minimize the warping.

   How would a three-point securing improve on warping, that is less warping,  in comparison? Would the glass plate make a better work of stabilizing the whole thing?


picclock,
Using glued in thread spares into the granite bed would work beautifully.

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline efrench

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Re: 3D printing
« Reply #60 on: August 16, 2015, 04:03:23 AM »
A good analogy would be a three legged stool compared to a four legged stool. It's easy to get three legs all touching the ground at the same time, but it's rather difficult to do the same with four. 

Four points are over constrained and will cause stress in the plate which may lead to the plate being warped. 

I think it's more likely the glass will take on the shape of the plate rather than straightening it.


Offline picclock

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Re: 3D printing
« Reply #61 on: August 16, 2015, 04:11:05 AM »
@EFrench

The bed levelling issue is mad. The bed is levelled by adjusting a heater board which buckles under heating due to differential expansion and is attached  via the screws and springs which is dubious at best. Much better (IMHO) to fix the glass and level it, then clip the heater board to the glass and let it go where it will.

I think some edge connection clamps for the glass, rigidly mounted to the y carriage with space underneath for the heater to attach would be a significant improvement, and once leveled should not need an readjustment.

Best regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline efrench

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Re: 3D printing
« Reply #62 on: August 16, 2015, 12:40:30 PM »
In that case I'd attach the heater to an aluminum diffusion plate. If you're going to be printing multiple items, then you will want to remove one glass plate to cool while printing on the next. 

My diffusion plate is 8mm thick (400mm diameter) Mic6 aluminum and is attached at three points.  The bolt holes are oversized to allow for expansion.  Initially the heater will be held against the bottom of the diffusion plate with springs.  If this isn't satisfactory, then I'll use a silicon glue. 

Offline Swarfing

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Re: 3D printing
« Reply #63 on: August 17, 2015, 06:26:04 PM »
Peter the ramps unit is fixed to the left triangle you see in the picture. unfortunately that is the only pic i have supplied by the owner. I only built him the basic unit and left him to finish all the wiring etc but I did have it running smoothly before handing it over. it leaves plenty of room for the electronics and the z axis is no problem at all with height. In short you can make things as thick as you like without affecting anything at all. The opening is still as per the original so no problems there with bed movement etc. Don't forget the original design is to try and make it as cheap as possible in-line with the reprap philosophy.
Once in hole stop digging.

Offline PeterE

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Re: 3D printing
« Reply #64 on: August 18, 2015, 12:49:41 PM »
Swarfing,

Thank you very much for answering.  It verified what I needed to find.

Just trying to compile as much info as possible before attacking the wood with a saw.

My version will be a wooden box framed Prusa i3 Reworked or at least something close to that. Bits have been ordered and are on their way in.  :drool:

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline picclock

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Re: 3D printing
« Reply #65 on: August 21, 2015, 02:00:15 AM »
Hi PeterE

Good luck with your build !!. Will you be doing a project log ? Will be interested to see what snags you encounter.

I have most of the parts for my I3 now. A couple of things worth mentioning. I have sourced some 16 tooth GT2 pulleys for the steppers. These will improve acceleration, especially on the heavy Y axis, though you may have to change the motor position to get a straight belt run. Also have the motors. Force produced by motor is directly proportional to magnetism produced by current. As all motors are inductive, current rises slowly, so speed of rise is controlled by voltage and Inductance of windings. Higher inductance results in more torque but slower operation, so there is a best compromise somewhere in there. I intend to run the drivers at 24V as this will halve the time for the motor to produce torque, also it is the design sweet spot for the drivers I am using, DRV8825's.  Have decided to alter bed design as shown in sketch below.

I found good youtube series of videos by a chap called Thomas Sanladerer, this one about pid tuning marlin :


Best Regards

picclock

« Last Edit: August 21, 2015, 02:59:03 AM by picclock »
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline PeterE

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Re: 3D printing
« Reply #66 on: August 21, 2015, 10:32:53 AM »
Hi picclock,

Have been thinking about a build log, but I have to be very clear that it will take time. I still work for a living which includes travelling at scheduled times so I think it would be very useful if I were not alone  :poke:

My log would be called "PeterE Builds a 3D printer". Perhaps you could make a similar one because I too think it will be nice to compare ways forward. But where to put it? In this folder or under Projects????

My pulleys are 20T as part of this kit I picked up from ebay:
http://www.ebay.com/itm/3d-printer-reprap-prusa-i3-movement-kit-GT2-belt-pulley-608zz-lm8uu-624zz-/181651872211?hash=item2a4b4b99d3
Felt like a fair price to me and I got all the important bits in one go.

When it comes to first setup I will follow the "standard" to begin with. This is learning on my part so keeping with standard makes it easier to acquire. Then I may well do some of your tweaks to enhance the whole thing. This also means I am starting out with the A4988 drivers which are part of this electronic kit - Hope it will work as intended because I think it was a silly low price.
http://www.ebay.com/itm/3D-Printer-RAMPS-1-4-Kit-Mega-2560-5x-A4988-LCD-2004-Controller-For-RepRap-/191233668287?hash=item2c866a34bf

When it comes to instructions I have found two which seems good, especially the one referenced below! This fellow also has an interesting idea of placing the Y axis motor opposite to standard - a thought to contemplate a bit but sounds interesting.
http://www.dragonflydiy.com/p/building-3d-printer.html

I also have some ideas about a new bed design but it is not finished.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline picclock

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Re: 3D printing
« Reply #67 on: August 21, 2015, 01:17:08 PM »
Hi peterE

That electronics kit was a steal. Only other thing you may want to add is the graphics display because that allows you to download a file to an sd card and print it standalone.

Having the y motor at the back and the home position at the rear also are both things I will try, then when it goes home at the end the model is pushed to the front ready to remove.

 I have just started looking at some of the parts and have run into an issue which I had encountered before. I pushed the linear bearings into the z axis plastic holders and found that the smooth motion degraded to lumps and bumps. I took one of the bearings out and the other one was still nbg. Then I remembered my previous experience where this happened. It was on an industrial pick and place robot where the hole for the bearing was out of round. Just pushing the bearing into the holder is enough to distort the case and destroy the smooth motion. should be OK with the tye wrapped ones but the z axis pairs will need the holders sorting if they are the same as mine. I was making new parts anyway so not a bodyblow, but a bit of a surprise. btw, the two z axis bearings can be replaced by one LM8LUU - still have to have a gentle holder though. 

I was thinking of putting my assembly attempts in project logs - cos thats the right place. Will probably call it picclocks attempt at an I3 3d printer. Should cause no confusion  :lol:

Will not start log or build proper until after I return from holiday on the 17th September.

Best regards

picclock

PS Just had a thought. You can program and check out the Arduino card just using the power from the usb lead. I did it to check for functionality but I was surprised at how long the compiler (Arduino 1.6.5) took to compile the marlin code ~4.5 mins. I thought it had crashed but it just takes a long time.  I7 64bit Windows 7. The other thing is that it recompiles to upload even if it has successfully compiled before.
« Last Edit: August 21, 2015, 01:58:55 PM by picclock »
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline PeterE

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Re: 3D printing
« Reply #68 on: August 21, 2015, 04:58:20 PM »
The graphics display was included! At the top in the picture!

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline Brass_Machine

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Re: 3D printing
« Reply #69 on: August 21, 2015, 09:09:09 PM »
Peter & Picclock,

I will be watching your build threads. I plan on building a 3D printer sometime in the next year...

Eric
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Offline picclock

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Re: 3D printing
« Reply #70 on: August 22, 2015, 03:13:10 AM »
Hi PeterE

The display card you have is a 4 line text display - as is the one I incorrectly ordered. The display card I should have ordered is a graphic display - but I screwed up and ordered the wrong one  :bang: One of those late at night jobs .. . 

The difference is that the graphic display can show temperature plots and other non text stuff and its easier to navigate between menus. Not sure if the text display will do the run standalone bit.

Have ordered correct one for 8.39 - don't usually make that kind of mistake. Pictures below for reference .

Best Regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline PeterE

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Re: 3D printing
« Reply #71 on: August 22, 2015, 08:56:56 AM »
Aha, THAT was the difference  :palm: I just thought it gave more text rows ...
Always at the edge of my abilities, too often beyond ;-)

Offline picclock

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Re: 3D printing
« Reply #72 on: August 22, 2015, 05:21:32 PM »
@ brass machine
typo error - should be years  :Doh:

hopefully you will learn a whole new lot of mistakes from the logs.

Best Regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline Arbalist

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Re: 3D printing
« Reply #73 on: November 07, 2015, 06:27:21 AM »
Good luck to all those building these machines but I'm still left wondering why. This article reinforces many of my thoughts. Even if I made plastic models the quality from many machines leaves a lot to be desired.

http://www.techrepublic.com/article/3d-printing-10-factors-still-holding-it-back/


RobWilson

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