It has taken many hours of trail and error, but It looks like I'm getting close to having my engraving dialed in. Extruded Acrylic is very difficult to engrave with a CNC Router, but it's much less expensive than Cast Acrylic, so I'm doing what I can with what I got. Look at the third line on each pic, almost 12 hours of playing with feed rates, depth of cut per pass, chip extraction methods, and spindle RPMs.