Warpign is caused by hot layers deposited on cold layers and the cooling, and hence shrinking, pulling the bottim up.
With good bed adhesion, this can lift the build plate off the heat bed at the edges.
PA6 and PA6-GF are particularly prone to warping. PA6-CF is much better as the CF cause a better thermal distribution through the part, reducing warping and its ugly sibling, curling.
Other methods to combat warping:
- Print with a warm build chamber. You can get a bit creative but do not do anything dangerous.
- Print with reduced layer height to reduce thermal mismatch.
- Print (even) slower.
