2 questions: PLA printing and How/use end of roll..

General Hardware
1

  1. It’s been a while since I printed PLA, like a longgggg time. I almost exclusively use ABS these days but I have a full roll of white PLA lying around that I’d like to use. A while back I seen some posts about the hex head clogging on extended prints using PLA because it softens up. What is the latest news, what temps should I use and how should I prep my PEI surface, I think before I would lay down green tape and glue ontop of the PEI…

  2. I have tons of rolls of ABS plastic lying around with only a handful of loops of plastic left on them, it’s too much just to throw out but not enough for a “larger” print. Is there some way I could fuse all these odds and ends together to make a larger roll? I don’t care about color difference, I usually paint most of my parts anyway. I remember seeing a crimper somewhere that let you weld two ends of the plastic together, but wasn’t sure if it was a gimmick or what…

2

I’m just using the standard Lulzbot Cura print profiles for PLA on the Lulzbot Mini at the school I’m working with with no problems: print temp is 205˚C, print bed is 60˚, remove print at 50˚. No real problems with that. (I believe we’re using eSun PLA.)

We print right on the bare PEI. We did have some initial difficulties with the print sticking too hard, and some kids were having a bit of difficulty removing it. I raised the z-offset by 0.1mm and it’s working fine for them now. (I suspect the problem with the z-offset was caused when we swapped print heads - the original jammed on one of their first prints. The replacement may have sat just a bit differently than the original. So now we have a spare head if they ever jam it again.)

If your PLA has been sitting around in an uncontrolled environment for a while, it may have picked up some moisture. You may want to throw it in a sealed container or ziploc for a few days along with a few desiccant bags to dry it out. Some folks will put a roll with moisture problems in their oven on a low temp for a while to dry it out. I’ve never tired that - if you do, make sure you don’t go over-temp and stick it all together.