Originally Posted by
louieatienza
You can get engraving plastic from companies like Rowmark and Gravograph. The way the engraving machines work, they have s spindle that's "floated" on a spring, and a depth stop collar, which also is a vacuum nose. That's how they achieve uniform depth.
For aluminum, you may try purchasing a spring-loaded engraving attachment for your CNC, and either 1) get diamond-drag engraving tools and grave the fonts with the spindle NOT running, or 2) get carbide engraving burnishers. They are used with a spinning spindle, and usually to remove the enamel layer off sheet brass and sheet aluminum engraving stock, and even work on anodized aluminum as well.
Also, use single-edge engraving tools, not end mills. You could buy them from Gravograph, but I believe LMT/Onsrud sells some. Amana also sells some engraving tools as well.
I actually worked for Crown Trophy for three years, headed the engraving department for the mail-order side and franchise training, about 18 years ago...