Irregular engraving or carving on a CNC machine is typically the result of differences in the height of the aluminum T-track. The image below shows that the text on the left and bottom of the material is less deep compared to the text on the right and top.
The most efficient method for eliminating inconsistencies in the T-track is by utilizing a Spoilboard and planning the surface. This process involves planning the spoilboard with a surfacing bit which eliminates any height irregularities introduced from the aluminum T-track, resulting in a level surface for the router. As depicted in the image below, the lettering is uniformly engraved on all sides of the material.
Additional Spoilboard resources: