Switching to PLA from ABS

I’ve been having great success printing ABS but when I switch to PLA (transparent blue) the first layer doesn’t stick very well.

I’m printing on the PET tape at 230/85 for the ABS (with Lulzjuice) and 185/60 for the PLA.

Do I need a different Slic3r profile for PLA? I’m using the 35nzl_draft setting for both that was supplied by Lulzbot.

What things should I change to get good PLA prints? I’d like to be able to print with the same PET bed as the ABS.

As far as I know PLA does not print well on PET. Other printing surfaces for PLA are Kapton, bare glass, blue painters tape, and bare acrylic.

The translucent PLAs you may want to try at a lower temp, say 170C, but that probably isn’t related to the sticking.

We print PLA onto PET and sometimes use ABS/acetone mix, but not always. PLA in general sticks way more than ABS. Perhaps your first layer isn’t low enough.

Should i have to readjust the z-height when switching from ABS to PLA?

yes, because the bed/nozzle temp is different so the expansion sizes will be different and all things in between

my best results with getting PLA to stick are on bare glass, cleaned with denatured alcohol, heated to 65c, first layer at 200c with moderate squish.

as an aside, I’ve found that cleaning the glass with alcohol too often degrades the adhesion for what ever reason. so I clean only when needed.

I tried trans blue one afternoon and did not like how it printed despite playing with the temp, plus the filament diameter varies more on that spool than any other.

I switched from the translucent blue PLA to black PLA and my adhesion problems have gone away.

I’m printing at 180C for the extruder and 70C for the bed.

I am seeing an issue now where the infill looks a little ‘ragged’ there are some holes here and there. It’s not as nice and consistent as the infill when using ABS. Any suggestions on what to tweak?

In slic3r under print settings -> advanced, there are extrusion width multipliers. Try bumping the infill multiplier to %150 or %200. That should clean up the infill a little. Material use will go up a little, but print time should be unchanged.

Thanks! I’ll give it a try the next time I have PLA on the machine.

Some users have encountered flaking or delamination when removing parts when printing on bare glass. We recommend printing with either the stock PET surface, or with the new PEI print surface that some of our more advanced users are using with great success.