The thing about the warping is, while most settings are nearly exactly the same as with PLA, there’s a few things that have to be the exact opposite. Once you get done fiddling with it, it actually prints like a dream. We even use it as our default material unless somebody requests otherwise. If it was unprintable, we wouldn’t be able to do that. Some stuff we’ve learned:

• Bed temp turned completely off!
• Use a fresh layer of a good 3d printing adhesive. (If your adhesive is heat activated, 35C should roughly be enough to activate without messing with the PHA)
• If you have an enclosure, open it up as much as possible. I noticed I have a lot more warping in my enclosed printer than my unenclosed one.
• Try out a few different fan settings. I personally have better luck with less fan.
• Put a big giant brim on it. Maybe even one made out of a different material than the object itself, if you’ve got dual extrusion.
• The higher the infill percentage and the more solid bottom layers there are, the more it will warp. So avoid that where possible.
• Most slicers probably already print the first layer at a chunkier line width than the nozzle size, but feel free to jack up the line width even more.
• Set the first layer pattern to concentric or Hilbert curve, evens out the distribution of forces that cause warping.
• Finally, if all else fails… Rotate the object until it’s sitting on a really impractical edge, then print it in sort of a “cradle” of support material. BVOH or PVA if you’ve got it. Basically make as little of it touch the build plate as possible? I don’t like this option because it requires dual extrusion and is pretty wasteful.

That all probably sounds pretty extreme but honestly these are worst case scenarios? Normally it just works. Maybe part of this also comes down to the fact that all the people making it have been refining their product for a while now to deal with the notorious warpy-ness, so it’s just not as bad as it used to be. We’ve used every brand we can find, Colorfabb’s AllPHA, Beyond Plastic’s BioPHA, Bosk’s Regen, they’re all pretty comparable. Here’s a vid of another PHA print in progress right now, one where we really didn’t even follow most of those tips above, and it’s going fine. It’s the second one of these.