High feed mills cut with a shallow lead angle, so the chip the tooth removes is thinner than the programmed chip load. This finds the programmed feed per tooth needed to hit a target actual chip thickness.
Factor = sin(lead angle). Programmed feed per tooth = target chip thickness / factor. Smaller lead angles need a larger programmed feed to deliver the same actual chip.
How it works
A high feed mill engagement happens mostly along its radius rather than straight into the cut, so only the component of feed along the lead angle becomes actual chip thickness. Programming the raw target thickness directly into chip load would under-load the edge and waste cycle time.
FAQ
Why is this different from radial chip thinning? Radial chip thinning comes from light stepover engagement around the tool diameter. Axial chip thinning comes from the lead angle of the cutting edge itself, common on high feed and insert mills with a shallow approach angle.
Related Guides
CNC Calculators · Radial Chip Thinning Calculator · Chip Load Calculator