Prusa Mini against MH build series PLA



  • Before I begin to think the MH build series PLA filament is garbage, I'm reaching out to the community for help. I just received a spool of PLA black 1.75mm and it jams in the Prusa Mini extruder multiple times. The first layer also has major quality gaps in it due to the extrusion not flowing 100% correctly.

    I normally use Hatchbox, Overture, and Polymaker PLA spools and they all flow flawlessly with the same default PLA settings. The MH stuff failed immediately and bound up in the extruder twice in a row. After pulling it out, I swapped it with Hatchbox to confirm flow continued normally.

    Why would the MH build series black PLA cause clogs in the extruder under the same settings as 3 other major brand PLA spools that rarely do so? For Prusa mini owners, the settings I use for all PLA mentioned above is 205C first layer, 210C otherwise.



  • @crazycabo350 Not all PLA are created equal. There are some PLA like for example Hobby King that print beautifully at 230. Now I think I used MH Build a long while ago and printed it at 220/225 range. I don't print a lot of PLA. On top of that it is known that not all printers report the temperature the same. There is some PLA like the one Anycubic sends with the printer that want to be printed at 190. So for each brand you will have to establish the proper print temperature for your printer. I would up the temp. For that reason - to establish proper print settings most will print a temperature tower to establish that



  • @crazycabo350 Just so you aren't thinking you're crazy, I bought a few rolls of their pro series PLA, all different colors, and I can't get it to print for my life. poor adhesion, poor extrusion leading to brittle parts. Almost sent back my printer. Tried some cheap overture from Amazon and what do you know, silky smooth prints from the exact same settings. I tried multiple heat settings on the pro series PLA and just can't get it to work unfortunately. Trying to send back for replacement.



  • @tterickson67 Never tried their pro series and I do very little PLA but maybe give them a call and ask whats up



  • @crazycabo350 Short answer - It's probably a heat break jam, and the hot end PTFE tube needs to be replaced - maybe hot end adjusted a bit, perhaps.

    Long Answer - I had the same problem in my Prusa Mini with MH Pro Series Lemon Yellow (btw...I would buy it again). Prusament PLA prints all day long - even with a "problem" tube. However, when switching over to the MH Pro - jams! Part of the mystery is that first layer cals will print just fine after you clean up the jam. Then maybe the first, second or a few layers will print before the jam happens again. The filament starts skipping, and the tell-tale clicking starts. Increasing the temperature, reducing speed, adjusting the extruder tensioner or screaming louder don't help. I store all of my filament in a dry box, so moisture isn't the cause.

    For me the fix was the PTFE tube. Dropped the new one in, and the stuff flows like warm butter. You may be able to use the old tube, if you trim the end and adjust the hot end spacing. See the manual and YT videos for how to adjust. But at USD 0.89 for a new tube, why bother.

    Bottom Line - For the Mini, my experience is that the tolerance to heat break jams is related to the hardness/softness of the filament. Prusament is a little stiffer, so the extruder can grip the filament without tearing it, allowing it to push hard enough to avoid jamming. I've found that "softer" filaments like MH Pro and HB PLA jam much easier. I consider eSun PLA+ to be a "stiffer" filament, and it prints fine with a "problem" tube. Curious...

    I'd like to relate this to actual material properties. I'd like to find a simple test method for filament hardness to validate my observations. Please advise me if you know of one.



  • You can also try drying the filament. I am not familiar with MH PLA, but their Pro series Nylon is pretty good.


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