BIG PLA Problems

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D3rax
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BIG PLA Problems

Post by D3rax » Mon Apr 01, 2013 7:55 pm

Hi everyone,

I started printing with PLA last weekend and after some extensive testing I have been able to have just 2 completely flawless prints (I use white PLa from Formfutura.com btw http://www.formfutura.com/abs-pla-frost ... .75mm-3mm/ )

I began printing with a standard Up! Plus extruder configuration and printed a scaled down owl model which turned out fine. I also managed to print the base and pins for the gear cube from thingiverse. My prolems began with printing the gears of the cube. The extruder stoped extruding at the end of the print.

The extruder was stuttering very loud only when I printed with ABS settings I was able to let the extruder keep extruding (but the prints are useless because it is impossible to separate the raft).

I then decided to use the penclip mod. I printed it out in ABS and after installing it the stuttering is gone but my extruder wont extrude. Only when i push down the fillament by hand it will extrude. The penclip mod gives enough grip because it is scrapping of pla, but the pressure is not enough to let it extrude during print (even on ABS setting).

Another thing I discovered is that while extruding the pla with the extrude option from the maintenance menu the PLA does extrude on ABS setting but the PLA keeps curling up after leaving the nozzle instead of streaming down in a straight line. So I guess the nozzle clogs up very fast. When I print ABS everything is fine though.

I hope you guys have any tips what I can do because im out of ideas....
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wilsonj
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Re: BIG PLA Problems

Post by wilsonj » Mon Apr 01, 2013 9:38 pm

Sounds like you have something stuck in the nozzle. Try cleaning it out.
Regards
Jamie
3DPrinterGear.com.au

D3rax
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Re: BIG PLA Problems

Post by D3rax » Mon Apr 01, 2013 10:11 pm

Hmm I thought because I still can print in ABS that the nozzle was not clogged? Any tips of fixing a PLA clog? Putting the nozzle in acetone wont help. Will heating it up with a solder torch do the trick?
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mb20music
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Re: BIG PLA Problems

Post by mb20music » Mon Apr 01, 2013 11:54 pm

D3rax wrote:Hmm I thought because I still can print in ABS that the nozzle was not clogged? Any tips of fixing a PLA clog? Putting the nozzle in acetone wont help. Will heating it up with a solder torch do the trick?

Yes heating it up with the propane torch will clear the clog

pleppik
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Re: BIG PLA Problems

Post by pleppik » Tue Apr 02, 2013 12:53 am

Many Up printers have difficulty printing PLA, since the extruder stepper motor can get hot enough to soften PLA. The filament then jams in the feeder mechanism, and you're out of business.

Some people have has success with PLA on an unmodified printer, but most people I've heard from who manage to print PLA have made some sort of modification to deliver more cooling to the feed mechanism.

After a jam, withdraw the filament and take a look at it. If the PLA filament is at all bent or warped then this is most likely your problem.

teamcarlisle
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Re: BIG PLA Problems

Post by teamcarlisle » Tue Apr 02, 2013 4:26 am

Also, incase you weren't aware, the up! Has a pla mode. Go to maintenance and install a new spool and it should have an option to switch to pla. I believe it just extruded at a lower temp but I don't really know. I still haven't tried printing in pla yet. Everything I've read so far is that even though the up! Supports pla it doesn't print it wel so I've stayed with abs.

D3rax
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Re: BIG PLA Problems

Post by D3rax » Tue Apr 02, 2013 3:25 pm

Well I successfully cleaned my nozzel with a blowtorch today. Actually I cleaned it 3 times in a row today. The nozzel is perfectly clean and has a clear opening. Im also able to extrude PLA in a nice staight stream now when I hit the extrude button in the maintenance menu.

But as sone as I start a print the extruder lays down a good line of pla but already after a few seconds the line gets thinner and thinner and eventually stops. The stepper gear is then scrapping of fillament and the print has failed.

I tried lowering the platform. This results in a few extra centimeters of good extrusion but very soon the nozzel looks clogged and stops extruding. Only when I lower the platform that much that the nozzel is "airprinting" it keeps extruding.

The only way to get a good print is setting the printer back on the ABS setting. It looks to me that there is not enough pressure, but the weird thing is that ABS is printing just fine.

Ow and about the hot stepper motor softening the PLA, I dont think thats an issue in this case because the extrusion stops just seconds after the start of the print....
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mr6k
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Re: BIG PLA Problems

Post by mr6k » Tue Apr 02, 2013 10:18 pm

I do not print PLA as I found it a nightmare.
An observation. I think it is still probable that the PLA is gooing up near the stepper motor. Your observation that you only get a "good" flow of PLA if the platform is a long way away from the extruder, says to me that, that the PLA flow within the extruder head is so weak that it needs a good length of PLA hanging out the bottom of the extruder that actually PULLS the PLA out due to gravity pulling on the long hanging length.

cheers

Peter

pleppik
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Re: BIG PLA Problems

Post by pleppik » Wed Apr 03, 2013 1:19 am

D3rax wrote:Well I successfully cleaned my nozzel with a blowtorch today. Actually I cleaned it 3 times in a row today. The nozzel is perfectly clean and has a clear opening. Im also able to extrude PLA in a nice staight stream now when I hit the extrude button in the maintenance menu.

But as sone as I start a print the extruder lays down a good line of pla but already after a few seconds the line gets thinner and thinner and eventually stops. The stepper gear is then scrapping of fillament and the print has failed.
This actually sounds like what happens to me when the extruder motor gets too hot and softens the PLA in the feed mechanism.

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scubamatt41
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Re: BIG PLA Problems

Post by scubamatt41 » Wed Apr 03, 2013 12:41 pm

Hi Xander,

How is the PLA coming of the reel? I mean, does the extruder motor need to "pull" it of the reel and push it down the nozzle at the same time?
Not that it should be any problem, in my case the mini works fine this way. You could check, if you give the extruder some slack filament and it extrudes the way you want it, then you know.

In that case there is to much friction in unwinding the PLA filament for the one stepper motor. Maybe the PLA get's/is, tangled on the reel?

Cheers, Matt
Always breath out on the way UP

D3rax
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Re: BIG PLA Problems

Post by D3rax » Wed Apr 03, 2013 6:48 pm

Hi Matt,

Dont think its friction from the reel, I gave the PLA some loose slack to be sure.

mr6k wrote:I do not print PLA as I found it a nightmare.
An observation. I think it is still probable that the PLA is gooing up near the stepper motor. Your observation that you only get a "good" flow of PLA if the platform is a long way away from the extruder, says to me that, that the PLA flow within the extruder head is so weak that it needs a good length of PLA hanging out the bottom of the extruder that actually PULLS the PLA out due to gravity pulling on the long hanging length.

cheers

Peter
Hi Peter, that is a real good observation. I indeed agree that gravity is a factor for creating a good flow when the platform is lowered. So probably the PLA is indeed to soft for the drive gear to create enough pressure.

But the weird thing is that the extrusion stops seconds after the start of the print. The stepper motor has at that point not gotten the time to get hot?

Maybe its the heat from the heating block that travels up the filament and already softening it at the point of the drive gear so it does not have enough torc?

I did notice that mine new up plus has a much smaller heatsink then the older models. This could explain that there is more heat traveling upwards.
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mr6k
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Re: BIG PLA Problems

Post by mr6k » Wed Apr 03, 2013 10:39 pm

You could be right about the heat traveling upwards from the extruder block.
I note you say the stepper has not had time to heat when the extrude stops. My experience is that the extruder stepper motor is hot even in idle mode. While it may heat up a bit more in extrude mode, its standby mode, to hold the filament in position, is at what seems to be a fairly high static current. I guess the only way to test this would be to somehow totally disable the stepper until ready to print and then see how long before extrusion stops. I know others play around with cooling the stepper etc with heatsinks, blown air etc, but for me I just don't want to handle PLA. It's awkward to use, bio degrades in sunlight, has a low softening point just above high ambient, is brittle and tends to form nasty sharp edges. So why would I not stick to ABS, especially now that it is available in many colours . Indeed if anyone has a printer in the St Albans, Herts UK area and wants a load of lengths of coloured PLA & some glow in the dark PLA, let me know, it's theirs for free collection.

cheers

Peter

D3rax
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Re: BIG PLA Problems

Post by D3rax » Thu Apr 04, 2013 6:31 pm

Well my main reason to use PLA is because its a bio plastic and it is supposed to be less toxic then ABS. With the fume cabinet I use the ABS fumes are not that much of a problem any more, but I regard PLA as a safer option.

In a little frustration today, I removed all the modification on my extruder en went back to the original setup. I also cleaned the nozzle one more time and decided to give the PLA one last try. I even added a bigger sponge with tyraps around the fillament to realy be sure its clean from dust before it enters the extruder.

And to my suprice I maneged to succesfully print 5 small prints (print time of 0,5 hours) in a row :) . I did not know that the stepper motor already got hot in idle possition. I will try some 2,5+ hour prints later this week to see if the heat of the stepper motor creats a problem then.
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scubamatt41
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Re: BIG PLA Problems

Post by scubamatt41 » Fri Apr 05, 2013 3:27 pm

He that's interesting. Can you please tell us what you removed?
Always breath out on the way UP

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