Make the longest possible lead in, the shortest possible pierce delay time, and make sure you do not have a delay at the end of cut that keeps the plasma on after the motion stops. Also...use the lowest power rating consumables for the material thickness.

-lead ins...longer, if you have room for it...is always best
-pierce delay time is the time programmed to allow for a complete pierce. The specs in the Hypertherm manual are pretty close to correct...however some machines add additional delays that add to the programmed setting. Experiment with shorter times....as long as the pierce barely makes it through to the bottom..then the pierce delay is adequate.

Also....machine acceleration rates (if sluggish) will cause more pronounced divots as well as any mechanical backlash that your machine may have.

Jim Colt