Author Topic: A kit 3D printer  (Read 13288 times)

Offline Pete49

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A kit 3D printer
« on: April 28, 2016, 12:22:37 AM »
After having my Da Vinci 3D printer for over a year I thought I would like to flash it to a better system (reprap type) but thought I should get another printer in case it goes pear shaped. Well last week I bought a 3D printer kit from ebay and proceeded to put it together. Went together just fine and loaded the software and firmware and tried a print. mmmmmmm not that good so levelled the bed again and checked all parts for accuracy but still no improvement so of the supplier of the machine and while they tried to help it only sort of fixed it. So now resorting to the various forums to see if I can get it working better. Just as well I decided to go this way or I may well have had no printer to play with. The kit version CTC clone uses Cura 14.07.01 but I'm not game to change anything until I can get this working properly. I'm still working with the suppliers of the kit with some success but any wise types here are welcome to butt in.
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: A kit 3D printer
« Reply #1 on: April 28, 2016, 03:15:07 AM »
 :worthless:

Need more details Pete,  example of print, blob, jammed filament.  Have you got a corner shimmed up with nuts, wood, dinner plate ?
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Offline Pete49

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Re: A kit 3D printer
« Reply #2 on: April 28, 2016, 11:26:02 PM »
Hi Joules here's a bit more info. Once the bed was levelled I adjusted the nozzle so a piece of paper just drags from under it at all 4 corners and the centre. (this was with a heated bed approx. 68C). The robot sample was average but when I went to print the whistle....well here's the result. It also fails to stick to the bed regardless of the glue method both Uhu or hairspray and even tried without adhesive as suggested by a few others. I stopped it after the first layers as it was not doing the fill in . I added the picture so you can see what it is supposed to be as we can't send stl files. Its using the marlin firmware I believe as it seemed to be the default though there are a couple others 1 of which is Reprap volumetric but not game to make changes as yet, if it helps
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: A kit 3D printer
« Reply #3 on: April 29, 2016, 12:47:34 AM »
First observations....

Pete, way too much glue, you need a film rather than a pool.  Get some genuine 3M blu tape, clean off the bed, apply tape where your going to print and clean tape with isopropanol.  Now set your print head, but to the surface of the tape (paper clearance as before). This is your new datum.  You now want to print a 1-2cm cube, solid or open topped shell.  You will be printing a LOT of them to fine tune the printer.

It doesn't all look bad, your extruder is working and the filament looks fairly even, no really thin or thick extrusions.  Your base layer fails as it hasn't anything to bond too.  The glue you have is too flexible, like printing on foam rubber and it's dragging on the print head.  You maybe under extruding, for the fill, or your step over is too large.  You need an amount of overlap to weld each line to the next and weld to the perimeter.  However till you can lay down a good foundation it's all guess work.

Show me a test print with no glue on the bed.  Let it build up a few layers deep, even if the print slips.  If PLA try using a bed temp of 40 C,  67 C is way over your glass temperature for PLA.

I should also ask what filament you print, ABS or PLA.  Do you print a border on your first layer to prime the print head, this is pretty important especially on small prints from cold.
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Offline Joules

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Re: A kit 3D printer
« Reply #4 on: April 29, 2016, 01:19:34 AM »
This is my standard test print. 25mm open topped cube, very useful for setting accurate print characteristics.



Note the outer ring printed to prime the head.  The above print didn't have the correct step over so my base fill was more like mesh than a solid base.
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Offline picclock

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Re: A kit 3D printer
« Reply #5 on: April 29, 2016, 03:51:58 AM »
@pete49

I have found that bed temperature and adhesion is a real issue, especially for larger prints. The problem seems to be that the surface temperature varies widely over the glass. I put a 1mm sheet of Aluminium between the glass and the pcb heater and found this to improve things considerably. For adhesion with ABS i have found hairspray coated with ABS juice works well with the parts removing easily when cold  (260C extruder, 100C bed). I have only made a few parts from PLA, and I used the blue masking tape that Joules shows in his picture.

@ Joules
Good calibration square. I have a calibration problem in that everything I print comes out ~0.14mm larger than it should. The error is constant regardless of length, and is in both directions - not Z. I am using the Cura slicer and wonder if that might be the issue. Have done tests altering the extrusion rate but its not made much difference, just produced poorer parts. Anyway, don't want to hijack Pete's thread, so will be updating my project log  hopefully today.

Best Regards

pcclock
« Last Edit: April 29, 2016, 11:19:25 AM by picclock »
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline Joules

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Re: A kit 3D printer
« Reply #6 on: April 29, 2016, 05:09:03 AM »
pcclock

I would say you are pretty near your limit at 0.14mm error.  I settle for 0.1mm per 50mm of length.  Too many factors come into play at that scale, note your error and scale design to compensate.   However before you do that, what layer height did you print, what nozzle size, that tolerance will change from filament to filament and also colour and how long the filament has been exposed to atmosphere.

My single walled cube above has another error.  Note the ring and the base, the ring is very rounded and the corners of the cube lift from the surface, my initial Z start is also wrong.   The single wall allows you to measure the true output thickness of your nozzle.  This would most likely account for up to half your 0.14mm error.   Check it against the calculated wall thickness or extrusion size in Cura.
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Offline Joules

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Re: A kit 3D printer
« Reply #7 on: April 29, 2016, 07:26:48 AM »
As it's relevant to Pete's issue I post an image of the cubes I used to tune one of the Mini Kossel printers, they are numbered in sequence, the Z issue was resolved by number 2, number 4 had an issue with over extrusion during a hard turn and resulted in some blobs down the edge.  A tweak to slow extrusion on deceleration, or direction change solved that, depends what your software allows to be tweaked.

Second picture looking into the cubes so you can see the bottom layer, they are numbered 5-1 left to right.

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Offline Pete49

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Re: A kit 3D printer
« Reply #8 on: April 29, 2016, 11:24:27 PM »
Thanks Joules I'll give it a go. I'm using PLA as it came with it but am getting another nozzle for ABS.
picklock I use hairspray for ABS with the xyz printer and it works well even on big prints with no lifting so assumed it will work with this printer once I get it running right.
Once I get it right I intend to make a enclosure for it as I have a sheet of plexiglass sitting in the way :ddb:
Thanks again and I'll be back
Pete
oops..........oh no.........blast now I need to redo it

Offline Pete49

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Re: A kit 3D printer
« Reply #9 on: May 01, 2016, 02:04:57 AM »
well here's last nights attempts as requested. I got a reply from the supplier of the kit and suggested floor temps between 60-70C and I found 64C was the temp when it stuck but well the pics explain it all. I'm about to check the feeder in case that is the cause as it seems to be lacking filament output in my view but open to correction.
The glass supplied is borosilicate so handles higher temps no problem....a small win there. Once this is running right I am going to re-engineer the unit and make it less flexible though its not too bad I think I can improve on it a little. I have been given a sink cut out about 1.5 inches thick which I will make my base from and with aluminium angle and Perspex for the enclosure it should be solid enough.
Pete
oops..........oh no.........blast now I need to redo it

Offline efrench

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Re: A kit 3D printer
« Reply #10 on: May 01, 2016, 02:24:32 PM »
I don't have any problem getting PLA to stick to a glass bed even without heating the bed.  I use 3M blue tape and wipe it with isopropyl  alcohol.  The alcohol makes a big difference.  It works just as well with a heated bed.  For ABS, it works too well.  It's really hard to get remove the print from the bed and even harder to remove the tape from the ABS.

Do you have a print cooling fan running after the first layer?


Offline Joules

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Re: A kit 3D printer
« Reply #11 on: May 01, 2016, 03:56:05 PM »
Ouch !!!

        Pete that is just nasty.....   Has your hot end got a blockage ? It looks very much like interrupted feed.  Does the hot end have a ptfe liner, it could be damaged and trapping the filaments free movement.  Can you extrude an uninterrupted filament with the head above the table.

      :bugeye:

Is the filament extruding straight out or curling back onto the head.  Pictures of your print head would be good. Have you calibrated the extruded for outputting 100mm of filament, it would then be worth extruding 100mm worth out the hot end to confirm the extruded is really pushing the full amount of filament out.
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Offline Pete49

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Re: A kit 3D printer
« Reply #12 on: May 01, 2016, 11:44:37 PM »
Hi Joules yep the hot end has a ptfe liner. I will check it tonight. I was thinking something is blocked but wanted confirmation before I pull it down. I may try a longer filament run before it starts to print to see if it helps. Just how deep is the liner supposed to go? All the way to the nozzle or just short of it? I replaced the original liner as it was damaged when I got the printer but the supplier sent me a 3 foot piece so I just guestimated it and I think it goes into the nozzle which may be the problem at least now I'm starting to think it may well be.
efrench I don't have tape as I never needed it on the other printer. Once I get this working right I will be going back to ABS as I have lot of it and PLA can't handle the outback sun very well and breaks down quick. I'm only using the PLA as it was supplied with the kit.
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: A kit 3D printer
« Reply #13 on: May 02, 2016, 01:29:22 AM »
Depends on the design of the print head, the ptfe should end at the top of the heat block as you would want the filament in contact with the heat as best you can.  That doesn't mean it couldn't extend to the nozzle, but it's not a good idea.  The ptfe should be cut as square as possible. If you see feathering of the edge, hot or cold end it's likely trapping the filament.

If you can put a drill shank in the ptfe and cut with a razor by rolling the ptfe, this will avoid uneven cut and the chance of picking up the filament.  Cutting with snips or scissors is a bad idea.

Be good to see a picture of your ptfe tube when taken out of the head, and the head components when they are apart.  I had this problem early on with the Rostock Max before changing to an E3D print head.
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Offline ddmckee54

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Re: A kit 3D printer
« Reply #14 on: May 03, 2016, 12:10:11 PM »
Pete:

How fast are you trying to print?  I had/have similar print quality problems with my printer when I try to print too fast.  At the present time I don't make any print moves faster than 40mm/s, although I'm slowly finding the parameters that I need to tweak and I'm bumping the print speed up a little at a time.

I agree about printing a LOT of the test cubes.  One thing that I did was I made my cube look like a die?(Pair of dice?)  Never can remember which is the singular form and which is the plural form.  Anywho, adding the dice faces only adds a few minutes to the print time and I have no question about how it was oriented when the cube was printed.

Right now I'm trying to correct an issue I've got.  When I print an inside corner, an inside corner on an overhang, the outside perimeter filament will sometimes tear loose.  Which just causes compound problems on the next layers, since there is NOTHING for the perimeter filament to print on.  I've found that it's REAL hard to print an inside corner on nothing but air.

Don
Too many irons, not enough fire.

Offline Pete49

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Re: A kit 3D printer
« Reply #15 on: May 04, 2016, 12:03:07 AM »
ddmckee59 I was printing at 50mm/s and that was working ok but then ran into trouble so contacted the supplier who gave me these parameters:
Print the wall thickness: 2
Print accuracy: 0.2
The print head temperature: (PLA temperature between 200-200 degrees, ABS temperature between 220-230 degrees)
The floor temperature: (PLA: 50-70 degrees, ABS: 110 degrees)
Print speed:(50-80), empty come (120-150)
Since then I have had the problems happening. I have even uninstalled the program and reinstalled it but it hasn't improved anything.
I found the floor temp at 65 degrees works fine and my filament now sticks to the bed but it now lays the filament too thin and as the pics show, a very web like structure. :Doh: Now off to double check everything again.
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: A kit 3D printer
« Reply #16 on: May 04, 2016, 03:40:03 AM »
Pete, I agree on print speed being about 50mm/s but nothing to stop you backing that off to say 30mm/s.  I am very wary of printing at 0.2mm layers with a 0.4mm nozzle.  The squish/weld factor is not great and I associate it in my prints with most failures.  For setting up and calibration I would ONLY recommend 0.1mm layers.  If you are under extruding as it appears this allows a fighting chance for the filament you do extrude, to get pushed onto the layer below.  It also means the first layer is pressed well onto the bed, you should be able to print onto a cold (20℃>) bed.  One of the bed materials I use here is Perspex, and cold the bond can be too good.  I will juggle temperatures and start the first layer at 190℃  and switch to 205℃ a couple of layers up, with PLA once the foundation has taken, back the bed temperature off to ambient, or down to 30℃

Check in your printer settings to see if there is an initial offset for the first layer, this can catch people out.  They think they are printing 0.1-0.2mm and the offset adds another 0.1mm or more, so the filament never gets pressed onto the bed.

Please give the extruder a test, make sure it pulls 100mm of filament when instructed.  Is your machine direct drive or bowden feed ?    You must get that 100mm extrude as accurate as you can, that determines the metering of molten plastic.  Run the test again this time feeding plastic through the hot end.  Mark your filament with a Sharpie, say 110mm away from the extruder, now extrude at a slow rate 10-20mm/s and measure your mark to see if 10mm is still sticking out the extruder.  If not change the step rate per mm in your software or find out if the filament is slipping/grinding in the extruder.

Measure the filament that gets extruded once cool, is it <0.40mm ?  If yes, you could have a nozzle blockage or damaged tip (a hot end crash can put a burr on a brass nozzle that can curl the filament)  Use a gas jet pricker to clear a hot nozzle, but be careful as this can also open out a brass nozzle. Another trick is to remove the nozzle and heat it to 300℃ or so with a heat gun, this will pretty much vaporize any remaining PLA residue (watch it bubble out and smoke)


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Offline Joules

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Re: A kit 3D printer
« Reply #17 on: May 04, 2016, 04:00:54 AM »
Hey Pete, don't get too down about it all.  I am having awful trouble with one of my printers (electronics) and it's costing me a huge amount of time and effort to sort out.  I should really pull my finger out and build my own printers as nothing on the market at the moment ticks all my boxes  :scratch:  under £2k   I really want five of them for my print farm.   The motley collection I already have are all different, with different methods of failure (the tech is still in its tantrum years)

 :bang:
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Offline efrench

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Re: A kit 3D printer
« Reply #18 on: May 04, 2016, 01:40:55 PM »
I recently had a similar issue with my printer.  The first few layers would print fine, then the extruder would start grinding the filament and the hot end would jam.  I was certain that the nozzle was failing, but it turned out the filament was the problem.  It was inconsistent in diameter, 1.72mm mostly, but occasionally it would be 1.8mm.  I think it also had absorbed some moisture.   If you haven't already, try printing with a newly opened roll of filament.


Offline Pete49

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Re: A kit 3D printer
« Reply #19 on: May 04, 2016, 11:55:57 PM »
Joules I'm not despondent as I know its a learning thing and I'm learning :lol: I think I forgot to send pics of the extruder which I will add to this message. I noticed last night that there is molten filament coming out of the heating block which I will examine tonight. The one thing I noticed is the bottom layers are a bit thin though I don't know what to adjust as I need to get it to print properly overall before I play with tweaks. I'll give the other things you mention a go and see what happens.
efrench the filament is fine (I hope) as it came from the supplier and humidity mmmmm what is that? rain too.... last time we had rain my 20 year old hid under the bed having never seen it before  :lol: well not that bad but close.
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: A kit 3D printer
« Reply #20 on: May 05, 2016, 01:18:55 AM »
Pete, I had the same hot end and extruder assembly on my Createbot Mini.  Yeah, a loose heat block, nozzle will drop the the nozzle pressure tremendously, leading to under extrusion.  I Changed  out the hot end for E3D components, but tightening what you have will be a good starter.  That internal ptfe tube caused me lots of issues too.
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Offline Joules

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Re: A kit 3D printer
« Reply #21 on: May 05, 2016, 01:36:46 AM »
The above show an example of blockage I could suffer due to the ptfe failing. All the E3D parts can be machined, they provide the drawings to make them, but I like what they have done, so support them by buying the parts.   I needed some beer tin shim for the existing heater cartridge to work. and sleeve the heat break tube to do away with the ptfe completely.  Look at E3D's design, just leave a little more meat on the heat break tube than they do, as ours is an unknown material (should be stainless) and may not be as strong.
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Offline picclock

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Re: A kit 3D printer
« Reply #22 on: May 05, 2016, 01:57:16 AM »
Hi Pete49

Just a thought. Have you set the filament and nozzle size correctly in the slicer?. I am not sure which slicer you are using but some of them default to a 3mm filament size. I did this early on by mistake and ended up with very similar symptoms.

As an aside, I have started using the Cura2.1 slicer, a beta version (bit buggy) and its extremely good with some very nice features. Will do a write up with pictures in my log soon.

FWIW I normally use a 0.2mm layer height with a 0.4mm nozzle with very good results - see pictures on my project log. These are fairly std values to work with. IMHO reducing to 0.1mm layer height just makes prints take twice as long with no other benefits.

Best Regards

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

Offline Pete49

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Re: A kit 3D printer
« Reply #23 on: May 05, 2016, 02:24:45 AM »
Well what an interesting day today. Its now printing as it should and it wasn't an error in the settings but I cleaned out the nozzle with a burn out. Once assembled I tried again and still the same problem but then thought I would check the 1 thing I hadn't ...the filament. As it was supplied with the machine I figured it was good but then as suggested I checked the filament and the first 5 metres of it was mostly undersize (1.70 with a few bits of 1.75 which the extruder would grip. That was why it was a thin feed  :lol: I cut the dodgy stuff off and now all is as it should be. Many thanks Joules and all the guys that assisted. I learned a lot more good info and improved my knowledge of 3D printing so I can put it to good use and jailbreak the Da Vinci printer later on. Once again thank you all for the help. :mmr:
 :beer:
Pete
oops..........oh no.........blast now I need to redo it

Offline Pete49

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Re: A kit 3D printer
« Reply #24 on: May 08, 2016, 12:38:16 AM »
Another problem has reared its head :Doh: I went to print a wheel with a 60mm dia. and after the first couple layers it went wonky and the next layer was about 10mm to the right while sitting in front of the machine so I stopped the print and retried it with the same result. I am now going to try it in the later version of Cura V15.04.5 and see what happens. WOW talk about offsets  :lol: I see where I can make adjustments but not sure how to proceed. Any ideas?
Pete
oops..........oh no.........blast now I need to redo it

Offline Joules

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Re: A kit 3D printer
« Reply #25 on: May 08, 2016, 02:31:35 AM »
Increase the current to the motors and see if you have step over, Z lift set as the head maybe catching the print during a rapid move.
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Offline picclock

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Re: A kit 3D printer
« Reply #26 on: May 08, 2016, 09:50:43 AM »
Hi Pete49

I think Joules has hit the nail on the head. Set the current for the motor with the pot on the stepper driver. You can usually do this with a meter, by adjusting the tiny potentiometer. Value should be set approx 15% below rated motor current. Only other thing to check is the jerk value in Marlin. It defaults to 20mm/sec but it may have been altered. You can find it in configuration.h after the acceleration and speed settings.

Hope this helps

Best Regards

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

Offline Pete49

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Re: A kit 3D printer
« Reply #27 on: May 09, 2016, 02:05:40 AM »
 :mmr:
Thanks again guys-------------------- it was the jerk thingi....All good now
Pete
oops..........oh no.........blast now I need to redo it