Today I remove lens for cleaning. Lens size is 12 mm but cover hole is 13.2. I made spacer ring from ABS for lens centering.
I’ve never checked to see how hot the lens gets during normal long operations, PVC starts coming apart at 140C and melts around 160C. A misaligned beam could create problems too…So if the temp of the lens is below that and no serious alignment problems… you should be ok.
I am used ABS melt at 200c. But I can change to PEEK later, Thanks for comment.