I have some boards that go through the assembly process on our SMT Line mounted on SMT Fixtures. Currently, we are experiencing some quality issues (shifting, tombstones, etc) on some of these assemblies as a result of not being able to keep the PWBs completely flat on the fixtures. I need to re-design some of these fixtures and would like to hear your feedback on companies you might have used in the past for fixture design. Some of these boards are very thin and tend to warp during the reflow process. I'd like to evaluate maybe 3-4 companies.Your assistance on this will be greatly appreciated.