Use Cycle 21 PILOT DRILLING if you machine a contour and then use a tool for roughing it out which has no center-cut end mill (ISO 1641). This cycle drills a hole in the area that will be roughed out later with a cycle such as Cycle 22. Cycle 21 takes the finishing allowance for side and the finishing allowance for floor as well as the radius of the rough-out tool into account for the cutter infeed points. The cutter infeed points also serve as starting points for roughing.
- Before programming the call of Cycle 21 you need to program two further cycles:
- Cycle 14 CONTOUR or SEL CONTOUR—required by Cycle 21 PILOT DRILLING to determine the drilling position in the plane
- Cycle 20 CONTOUR DATA—required by Cycle 21 PILOT DRILLING to determine parameters such as the hole depth and the set-up clearance