Engineering Reference

Feed per tooth (chip load)

The thickness of material each cutting edge removes per revolution, in milling.

Definition

Feed per tooth is the real control on tool life in milling, more than surface speed is. Too low and the edge rubs, work-hardens the material and dulls; too high and the edge chips or the tool deflects. The F = fz · z · n relationship converts it to table feed.

It is not the same as feed per revolution, which is the total advance per spindle revolution and equals feed per tooth times the number of teeth.

Common misuse

Using feed per revolution where the tooling catalogue specifies feed per tooth, which under-feeds a multi-flute cutter by a factor equal to the flute count.

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