I have been trying to engrave Optix acrylic sheets and have not been able to get as good of a result as I would like. I am using a Onsrud 37-21 bit which is a 30 degree engraving bit with a .005" tip. I have played with feeds from 50 to 175 ipm but since the items are small anything over 100 ipm does not seem to make a difference. Also I have played with rpm from 7k to 12k. The best improvement was to make two passes with the first at .006" and the second at .008". Any ideas on how to get cleaner letters?
Alan