1.75 PLA filament in a Mini 2

I’ve seen several threads about problems using 1.75 filament in Lulzbot printers, but not one that discusses my exact issue.

I have a spool of white 1.75 PLA filament from AIO Robotics. I’ll admit I have had the spool for several years (got a free sample long before I had a printer,) but it was still sealed in the vacuum bag with desiccant packs inside.

I tried to print using PLA settings (Ploylite PLA) I had used with Lulzbot green filament that bought from Lulzbot. When I watched it print, the head was clearly too high from the bed and you could see it extruding in mid-air before landing on the bed. This caused it to not adhere whatsoever to the bed.

Realizing that this material had for it’s properties a diameter of 2.85 mm, I created a new material by duplicating the “PLA (Village Plastics)” and changing the diameter to 1.75. The only information on the box was the diameter and the printing temperature which was 195-230 degrees. I checked the “Print Settings” tab and found that the default printing temperature was 205 degrees and felt that would be fine. I honestly didn’t know what else to change.

After a false start or two, while I got the tension correct, I was able to successfully print an object. However, what printed was frail and despite using a 90% fill, it could EASILY be crushed. This was a 17 mm solid object.

My question is, what other setting in the material should have been changed? I left the density at 1.24 g/cm3 and everything else the same.

I’ve e-mailed AIO Robotics, but thought about posting this while waiting for a response.

-Harry Delien

https://lulzbot.com/learn/tips-and-tricks-printing-with-1-dot-75mm-filament

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Thanks, I’ll try the suggestions that I haven’t already tried.

I read through the link that @iguanaman provided which involve retraction and slowing print speed, but what about the flow rate? Wouldn’t increasing that help to insure the head has enough material/pressure to print?

If you want to use 1.75mm filament, you should either buy a 1.75 head (M175 v2 Tool Head | 1.75 mm | Single Extruder | 0.5 mm) or convert your existing head with some hardware modifications.

1.75mm filament doesn’t “fit” the filament path going through your 3mm extruder. The loose fit means that the filament isn’t uniformly touching all of the walls in the hot-end and it can pool. The filament coming down from the cold end isn’t as wide as the “pool” and this can cause problems … including filament trying to back up into the cold end.