Multi-Material PETG Support for PLA Print help
I have been trying to get PETG to work as a support material for my PLA prints with poor results so far. First I tried to use PETG as an interface layer, which would just fall right off if it stuck to the PLA main support structure at all. I abandoned using PETG as the interface since it is cheap anyway, and am now using it as the full support structure. Now it struggles to adhere to the bed (70c since PLA is also on the bed), and also blobs on a PLA support tower because, PETG and PLA dont stick together well. I used the article here to help https://help.prusa3d.com/article/combining-materials-xl_498103 so its not like my tower is falling apart or any of the basic issues.
One solution I am thinking is not printing the PETG on the purge tower, since it can have under extrusion at the start of supports, and just have a tiny PLA purge tower so the main print is still at the right pressure and stays beautiful.
Is there any way to do this, or is there a magic PETG support for PLA print profile I am missing that can make my life much easier?
RE: Multi-Material PETG Support for PLA Print help
I haven't tried this, but you could put a couple of solid PETG layers right on the build plate, which are large enough to maintain adhesion. Then support it from there. If it doesn't stick you could apply glue stick or hair spray selectively to these areas.
RE: Multi-Material PETG Support for PLA Print help
Thats not a bad idea, a .5mm slab of PETG as a "raft" for the print. The purge tower is still an issue if I cant turn off PETG going onto that tower but its at least a start
RE:
I've been doing the reverse with great success. (PLA interface layers on Petg) The key is you have to design your own supports and build a wall and notches around the interface layers so that they can't move.
You can see below the white is PLA and the blue is PETG. See how I've contained the PLA with the PETG.
RE: Multi-Material PETG Support for PLA Print help
Wow! Those look great! And that is my next plan for tonight in designing all the support myself. The notches are genius I would have never thought of that!
RE:
Thats not a bad idea, a .5mm slab of PETG as a "raft" for the print. The purge tower is still an issue if I cant turn off PETG going onto that tower but its at least a start
I get along just fine without any wipe tower, but I have nozzle wipers installed (and 0.4 nozzles). Have you tried setting Print settings -> Multiple Extruders -> Extruders -> Wipe Tower Extruder to the one loaded with PLA ? The way I understand this setting, any gunk that doesn't stick properly should wipe off on the outer tower wall. So if that holds you're golden.
To add my 2 cents to the above poster: supports really need to be touching or they have no effect at all on sagging. It really almost doesn't stick, acting almost like a shelf to rest the print on. I just set the contact distance to 0.
RE: Multi-Material PETG Support for PLA Print help
So the wipe tower does still give me blobs since that actually is where they form. I do have that setting enabled but sometimes it wont stick. Ill try without because heck, why waste material if I dont need it! Using a combo of both your advice has been super helpful, making my own supports and also giving a slab for everything to stick is working pretty well so far to the point im not constantly getting failed prints. Now I can perfect it and keep going so thank you both!
RE: Multi-Material PETG Support for PLA Print help
That's good to hear 🙂
Basically I use wipe towers for a) flexibles and b) when there are many layers where one or more colors have only very small lengths to print (let's say < 2cm). In all other cases it's either entirely unneccessary or you can get away with "wipe into object infill" (not recommended when you have very light and dark colors in the same print, as it might show through the walls). I have one spool of filament that blobs whatever I do, maybe it's just tough luck with yours and better to change brands.