Problems with PLA part way through print

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brianeh
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Problems with PLA part way through print

Post by brianeh » Sat May 16, 2015 1:59 pm

I have suddenly started having a problem with PLA filament with UP 2 plus.

At about 1/4 of the way through a print the filament feed starts stuttering and the filament stops feeding. The feed just thump, thump, thump as the head moves about and the filament stops extruding.

I can stop the print and perform an extrude and that works just fine.

Before this started happening I upgraded the UP software. (I don't know if there is some relationship).

Anyone have experience with this?

brianeh
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Re: Problems with PLA part way through print

Post by brianeh » Mon May 18, 2015 10:10 pm

I have continued to work though this and the issue is definitely linked to PLA, not ABS.

I have tried different size prints, etc.

It is almost as if the head gets too hot and causes the PLA to seize in the print head. (I have already ran into printing PLA when set to ABS, not fun to clean out). this issue is not that the filament type is set incorrectly.

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DrewPetitclerc
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Re: Problems with PLA part way through print

Post by DrewPetitclerc » Tue May 19, 2015 6:30 am

brianeh wrote:It is almost as if the head gets too hot and causes the PLA to seize in the print head. (I have already ran into printing PLA when set to ABS, not fun to clean out). this issue is not that the filament type is set incorrectly.
Hi Brian,

You should do a little research, PLA does not like the all steel barrels of the newest generation of 3D printers, PLA swells when warmed and "sticks" to the inside of the steel tube causing more friction, this added to the back pressure from the nozzle will eventually cause a jam or strip-out, also with the UP using a direct drive the stepper motor can get very hot and pre-soften the plastic also making strip-out easier.
The solutions are as follows;
1 actively cool the feed gear or stepper motor, the gear is easier to cool with a compressor.
2 replace your SST barrel with a "Recreus" model, this has a hi-temp nylon sleeve to guide the plastic to the melt chamber smoothly.

If you do a little searching and some research you will notice that most all home built printers use an all PTFE (nylon) barrel and they print with PLA.
I have been printing every type and color of plastic and wood and metals on my "UP Plus Pro" for a couple of years now, I currently have over 90 spools of plastic from almost all the suppliers and regularly I am give test samples to try and evaluate.

Good luck
Drew
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
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roller
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Re: Problems with PLA part way through print

Post by roller » Tue May 19, 2015 8:48 am

One more solution sadly not viable on an Up but how most other printers avoid the issue:

3. Turn down the current to the extruder motor so it stays cool and the stepper motor acts more like a heat sink rather than heat source.

Doing so lowers the torque and presumably PP3DP has it running so hot in the Up printers because the stepper doesn't have sufficient torque otherwise.

brianeh
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Re: Problems with PLA part way through print

Post by brianeh » Tue May 19, 2015 2:31 pm

Thanks!
My searching was not uncovering these details.

I am aware that the UP print head is a bit hotter than most. But I seem to be the only person that reports PLA problems with the UP (that search is uncovering) so I was starting to think it was only me.
I have found after market heads that allow better temperature control of the head.

But I have just not had the time to go deep into the research to really understand everything.

Thanks again!

roller
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Re: Problems with PLA part way through print

Post by roller » Mon May 25, 2015 12:48 pm

You are not finding much on PLA because most people get absolutely nowhere with it and give up immediately. Swapping to another head (and the reall issue is the extruder not the head) is not really an option as you need to be able to customise the feed ratio... which we can't do because the Up is a closed not Open system printer. In a nutshell the issues are as Drew and I stated earlier. There are cooling solutions discussed on this forum along with filaments that are less prone (my preferred method) but overall PLA is a pain in the ass for Up owners.

http://www.pp3dp.com/forum/viewtopic.php?f=18&t=37126 - look a couple of posts down and Drew links to a few more
http://www.pp3dp.com/forum/viewtopic.ph ... 04&start=0
http://pp3dp.com/forum/viewtopic.php?f=19&t=2673
http://pp3dp.com/forum/viewtopic.php?f=19&t=54304

stormychel
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Re: Problems with PLA part way through print

Post by stormychel » Wed May 27, 2015 2:58 am

Who needs a printed object that deforms under warm tap water anyway???
@stormychel

roller
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Re: Problems with PLA part way through print

Post by roller » Wed May 27, 2015 12:32 pm

stormychel wrote:Who needs a printed object that deforms under warm tap water anyway???
It's lower warp properties and delicious smell are advantages ... but yeah, I once lost (melted) a design model I left in the car on a hot day on the day of a crit. Not happy ... not happy at all.

stormychel
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Re: Problems with PLA part way through print

Post by stormychel » Wed May 27, 2015 12:47 pm

Yep the lower warping is a +... I don't care too much about the smell :)

I mainly print in HIPS now, it has lower warping too, and is non-toxic, but have a spool of PETG ready to be tested. Now all I need is some time...
@stormychel

roller
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Re: Problems with PLA part way through print

Post by roller » Thu Jun 04, 2015 8:13 am

The roasting PLA smell always makes me want some fresh donuts or Churros.

stormychel
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Re: Problems with PLA part way through print

Post by stormychel » Thu Jun 04, 2015 9:01 am

roller wrote:The roasting PLA smell always makes me want some fresh donuts or Churros.
Conclusion: ABS is better for your health :D
@stormychel

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