CNC rotary engraving systems use a computer controlled rotating cutting tool in a motorized spindle to remove surface material. The rotating cutting tool, or cutter, cuts into the surface of the material to a predetermined depth and produces a groove of the same shape and size as the tool.
The rate of the cutter rotation is referred to as the cutting speed, and the lateral movement is the feed rate. Each has a profound effect on the quality of the finished cut. In general, softer materials may have higher cutting speeds and feed rates and can be engraved in a single pass. Harder materials require lower cutting speeds and feed rates and may need to be engraved in two passes. The first pass will remove most of the material and the second pass will create a clean cut.
Rotary engraving can be performed on a wide variety of materials including acrylic, soft plastics, rigid plastics (phenolic), soft metals (brass and aluminum) and harder metals (steel and stainless steel).
A common application of rotary engraving is to remove or mill away the background to leave raised letters or images for a “cast” look or create braille print.