@Marc_Schaefermeyer but of course different spindles would have different speed requirements. Let’s keep it simple and just talk about one spindle being in use. The cuts are in 1x1x1 mm cube grids. The person would adjust a “minimum stress” value (1-5) if the cutting surface of the spindle is too small. The idea behind this is that if you cut in passes smaller than the part of the bit that does the cutting then you already cut part of what you needed to cut and so you should be able to go faster.