Depth of cut

Depth of cut is the thickness of material removed in a single pass, measured perpendicular to the tool's feed direction. It is chosen alongside cutting speed and feed rate, and, together with width of cut, determines how many passes are needed to remove a given volume of material and how much cutting force the tool and machine experience.

Why roughing and finishing use different depths of cut

A deeper cut removes material faster per pass but increases cutting force, tool deflection and vibration risk, which is why roughing passes typically use a larger depth of cut than a finishing pass, which prioritizes accuracy and surface finish instead.

Where depth of cut is set

Not on the drawing; it's a programming parameter chosen based on material, tool rigidity and machine capability, not specified by the part's requirements directly.

Common mistakes

Using an aggressive roughing depth of cut on a thin or unsupported feature, risking deflection or vibration that a more conservative depth would have avoided.

Is depth of cut the same as width of cut?

No, depth of cut is measured perpendicular to feed direction (typically the axial direction); width of cut is the radial engagement of the tool into the material.

Why is depth of cut smaller for finishing passes?

Because a smaller depth reduces cutting force and deflection, which helps achieve a tighter tolerance and finer surface finish.

Does machine rigidity limit achievable depth of cut?

Yes, a less rigid machine or setup generally needs a shallower depth of cut to avoid excessive vibration or deflection.