We are new to the Shopbot CNC world and are trying to route Rowmark engraving material. The results are not acceptable due to tooling marks. We are using an 1/8" end mill with slow feed rates ( 20 inches per min), moderate router speeds ( 14,000 rpm) and cutting depth of .02. The tooling marks are not everywhere but appear on certain letters inconsistently.

Any thoughts on how to achieve a cleaner end product?