#Trouble with black PLA Pro consistency

20 messages · Page 1 of 1 (latest)

gentle mango
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Hi everyone,

I recently purchased a 5kg spool of PLA Pro in black and just can't seem to get it to print consistently. I've purchased a lot of Polymaker filament so far, including many spools of PLA, a few of PETG, one of TPU, and some PA6-CF and PA612-CF and have had nothing but great results with them, however this is my first time with PLA Pro and it just doesn't seem to be working. Some prints come out perfect, and others (especially ones that take a few hours) just don't seem to behave.

I had some issues printing directly from the 5kg spool so I respooled it to an empty 1kg (using the pastamatic respooler) as I thought it might have been related to the filament being damp, and I dried that 1kg spool in a dedicated filament dryer at 55c for 24hrs just in case, but it didn't seem to change anything.

I've tried varying the extrusion multiplier from 0.92 (way underextruding) to 1.0 (definitely overextruding), printing from 200 to 220c, printing as slow as 40mm/s max, making sure there was absolutely zero potential drag pulling the filament into the extruder (using a rolling filament holder with 608 bearings and a direct feed into the top of the extruder, even a small gust of air could turn the spool), minimal cooling, 100% cooling, using a different nozzle... and I just can't seem to get it to be consistent. Maybe it's a bad spool, maybe I'm dumb... not sure.

I ran a max volumetric speed calibration and it looks like it is capable of up to 15mm^3/s consistently, but even setting the max to half of that results in occasional issues. I've attached pictures, does anyone have any idea what could be going wrong?

Thanks to anyone who bothered to read all of that!

20240301_174943.jpg 20240301_175008.jpg 20240301_175034.jpg 20240301_180430.jpg
gentle mango
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<@&1122587817768398938> forgot to tag!

lucid merlin
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I gotta ask, did you try drying the filament?

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and also cleaning your nozzle?

fading field
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The first picture looks like a partial clog. The last two look like poor cooling on the overhangs

cerulean vortex
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First 2 are extrusion and retraction

second 2 are cooling

lucid merlin
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Agree ^ but I've rarely found clogging happening so on-and-off?

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Maybe I'm just lucky to not have had that arise...?

fading field
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It happens, especially if you swap back and forth between high temp and low temp materials. There could be a piece of nylon stuck in there that won't pass because it's not hot enough. A cold pull usually resolves it.

lucid merlin
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Oh makes sense - i usually run a bit of cleaning filament through, so i probably never have the misfortune of that happening.

gentle mango
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I've dried the filament for 24hrs at 55c, and have also run about a foot of cleaning filament through after the last filament change. I've also printed these pieces at 100% part fan, even tried the aux cooling fan up to 100% too, so I'm not sure how much more cooling it could possibly need. I also tried regular PLA right after these and it prints perfectly, but when I go back to the PLA pro, even with a cleaning filament run in the middle, I still get this.

The only thing I haven't tried is a cold pull, so I'll give that a shot.

I read it could potentially have something to do with filament diameter inconsistencies but I have no idea how to test that, what do you all think?

fading field
gentle mango
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Z seam is definitely aligned and not random. Is it possible the clog is being caused by the filament itself being dirty somehow?

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I will experiment more with cooling, maybe my room is too hot

fading field
gentle mango
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Ok thanks. I'll give some things a try, I appreciate the help!

celest pelican
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I suspect you just need to clean the extruder gear. I imagine your printers extruder was skipping when you tried using the 5kg spool. Usually too much drag from your spool mount and design. It's a lot of weight to pull and if there's drag, the extruder just takes chunks out of the filament. Those chunks of plastic will be in the extruder gear and cause slippages unless you clean it out.

That's what i suspect is causing the missing extrusions in your images

gentle mango
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I originally thought it might have been drag as well, so I made sure there was none at all, so little in fact that the 5kg spool was starting to unwind itself from having no resistance at all when it started pulling filament into the extruder. Regardless I took your advice and opened it up but it looked like the gears were clean, I'll have to remember that tip for the future though.

I ended up running about two feet of cleaning filament through it again, this time at 260c and hoped that would be enough to clear out any partial clogs. After all this I was still having issues, until I read a post on Reddit about someone having issues with a matte finish with this exact filament... I hadn't really thought about it, but mine looked rather matte too. Someone from Polymaker had responded saying they weren't printing hot enough, even though they were printing at 220c (which is the high end of the recommended temp on the label). They went on to mention that fast industrial printers were printing their filament in the 400c range and that it's purely a starting recommendation and to try higher temps.

So I took that advice and dialed it up to 240c and by golly, it worked! Curled overhangs went away, extrusion issues went away, the surface finish started looking more shiny, and I was able to start dialing up the speed again without causing more problems.

It's very unintuitive considering everyone having similar issues online seem to keep being told to print slower, print cooler, add more cooling, etc. but none of those things worked for me. Even printing overhangs at 10mm/s was causing upward curling and seemed to make the filament stick to the nozzle and get dragged away, but at 240c it doesn't stick at all and cools in place.

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This filament acts a lot like PETG in some ways, I just was stuck in the mindset of PLA