has someone had issues printing with pushplastic 3mm pla?

General LulzBot Mini
1

Hi,

I recently bought a batch of push plastic brand pla and so far I’ve had a bit of grinding issues with the filament. It stops coming out in the middle of prints and I get ghost printing. Then when I remove the filament its been chewed on. Ive already gone through a lot of steps to solve the problem unsuccessfully:

  1. measure filament - it is at the top 3mm range but always below 3mm
  2. run unclogging procedures posted by lulzbot - I get constant extrusion no problem
  3. adjust extruder latch tension using the 3d printed jig
  4. lower printing speed
  5. experiment with temperature (used 195 to 210 temp range)
  6. lower retraction speed

Is there anything else I should be thinking about? The strange thing is I have another mini and that one isn’t having the same issue.

Thanks!!

2

If it’s working in one mini, it should work in the other one. If not, it could be a feed issue. On the one that is causing you trouble, remove the the fillament from the extruder with the extruder at print temperature, let it cool down and remove the extruder body from the machine, then loosen the bolts slightly between the hot end and the extruder body itself. Then use something about 3mm in diameter to probe down the fillament shaft and ensure that the hole in the extruder body and the hole in the hotend are perfectly lined up. You’ll also want to check the idler arm bearing and make sure it still turns while you are checking that.

Then reinstall everything and try a test print. If it still doesn’t work buy a cheap infrared thermometer from a tool / auto parts store (~$30 or so) and aim it at the two hot ends and see if the one that is having problems is actually getting hot as it is supposed to be.

If that doesn’t do the trick, E-mail their sales department at sales@pushplastic.com and see if they can find out what the issues are. There was a reddit forum thread about their fillament a while back where someone had an issue with the white colored plastic and they took care of him.

3

Thanks! I’m going to give that a try. I do suspect that the printer is not heating the way it should because I can heat it up to 230 with PLA and the PLA wont even liquefy which is pretty weird.

4

BTW another thing, even when I feed thinner filament (which actually does work in the printer and doesn’t get stuck) I do feel like there is something that the filament bumps into before it can actually feed into the extruder. I talked to lulzbot support but they told me this is intentionally misaligned to prevent the filament from curving inside the extruder. Any thoughts?

5

It is quite possible that the heater core or the thermistor has damaged itself and needs replacing. Support should be able to get you all set with that if thats the case.

As for allignment, The only thing i can think of is that you and support were talking about different parts of the extruder. they may have been referencing the idler arm offset from the bore, I don’t know. The support guys are pretty sharp so I wouldn’t second guess them.

Here’s the Mini print head assembly guide so you can see how it goes together. https://ohai-kit.alephobjects.com/project/86797b55-7d08-4c6d-be77-3c116a320547/