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Topic: PLA speed?

I am experiencing roughly 48 hours per kg with PLA, it seems the pellets simply cannot feed fast enough into the filastruder as they can with ABS.  All PLA pellets I have found are around 3-4mm round.  Has anyone been able to speed up PLA?

I am extruding at 150C with the fan barely blowing on the plastic running at 6v to keep speed and CFM down.

ABS times are around 10 hours per kg, which I am extremely happy about.   I find myself using PLA almost as fast as I can make it and I am only using a single printer at the moment.  Any assistance is greatly appreciated!

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Re: PLA speed?

The problem isn't the PLA pellets feeding into the auger, nor the size of the pellets. I've run different sizes and shapes of various materials and as long as the pellets are under ~6mm in the biggest dimension, they'll feed fine. It just *looks* like they don't feed because there's nowhere to go - there's a big mass of plastic ahead that is very thick and viscous owing to the low extrusion temperature, which I'm about to get to:

150C is low! That's also probably why you're having to reduce motor speed so much to avoid overload.

If you:

drill out the nozzle to 1.7mm or so ($2 metric drill bits at McMaster)
increase to 160C
bring the motor back to 12v

you should see a pretty significant speed improvement.

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Re: PLA speed?

Also, here's a nice writeup on PLA extrusion:

http://www.soliforum.com/topic/7648/bas … s-request/

If memory serves he was going 1kg every 4 hours, but was running 3mm filament, overvolting the motor along with a host of other modifications. He also used a hopper shaker, I didn't see much gain in a  horizontal setup but folks ave reported gains in vertical setups.

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Re: PLA speed?

elmoret wrote:

The problem isn't the PLA pellets feeding into the auger, nor the size of the pellets. I've run different sizes and shapes of various materials and as long as the pellets are under ~6mm in the biggest dimension, they'll feed fine. It just *looks* like they don't feed because there's nowhere to go - there's a big mass of plastic ahead that is very thick and viscous owing to the low extrusion temperature, which I'm about to get to:

150C is low! That's also probably why you're having to reduce motor speed so much to avoid overload.

If you:

drill out the nozzle to 1.7mm or so ($2 metric drill bits at McMaster)
increase to 160C
bring the motor back to 12v

you should see a pretty significant speed improvement.


Fan is running at 6v not the drive motor.  At 150c I am getting 1.67mm with the fan and 1.58 without.  At 163C I am getting 1.38mm with the fan. The motor isnt overloaded at all, it actually shows green from time to time.

I dont want to drill out the nozzle just yet as I only have one and need to run ABS as well lol

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Re: PLA speed?

I'll shoot you an email, maybe we can get you another nozzle. smile

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Re: PLA speed?

Thanks! Do you really think that a .1mm expansion in the nozzle will increase my speed that much?  I just think the PLA cannot be packed so closely in the auger like ABS pellets can and that may cause the speed issue.  Diameter is good as is printing performance.

I am running a vertical set up but oddly the PLA doesnt need shaking, ABS, however does. The round-ish nature of the PLA seems to feed just fine into the barrel. Been thinking of using a vibration motor from like a PS1 controller hooked up to the same pins as the motor that turns the filawinder, basically turning on the vibration when the spool spins.

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Re: PLA speed?

It isn't the increase in nozzle size that will help your speed, it is the fact that an increase in nozzle size lets you increase the temperature, making it easier to push.

The pellet size and shape is not the influence here, based on my experience. If it was there'd be a significant different in speed using regrind, but that is not the case.

Also if the motor is not showing green steadily, that means it is being current limited at times.