I’ve been using a lot of Siraya’s PPA-CF Core material, since it seems to be about the strongest thing out there. See this video from MyTechFun: https://www.youtube.com/watch?v=nM0GR_x2iQs
My only complaint about it (other than overextrusion issues, see previous posts) has been that supports are a bitch to remove… so I’ve had to increase the Z distance to 0.3 mm, which leaves a shitty surface finish.
I tried the Bambu PA/PET Support and the Polymaker Polysupport for PA12 on a guess that they might work here too, but neither one worked with the PPA. They just stick together way too well.
I finally bit the bullet and ordered a roll of this expensive stuff: https://www.raise3d.com/products/raise3d-industrial-ppa-support-filament/
First SL-15 lower finished this morning, and it worked beautifully. If you’re in the same boat, you should give it a try.
