Free Tool

Chip-Thinning (RCTF) Calculator

RCTF = √(D / (2 × ae)) — find your adjusted feed, RPM, and MRR for high-efficiency milling passes where ae < D/2.

Cutter Diameter D (mm)

Radial Depth ae (mm) For HEM: ae = 5–15% of D. Correction applies when ae < D/2.

Axial Depth ap (mm)

Recommended fz (mm/tooth) Use manufacturer's value for ae = D/2 (half-slot)

Number of Flutes

Cutting Speed Vc (m/min)

Radial Chip Thinning Factor (RCTF)

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Adjusted fz (program this)

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Spindle Speed

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Feed Rate Vf

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MRR

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How the RCTF Formula Works

When the radial depth of cut (ae) is less than D/2, each tooth exits the cut before reaching maximum chip thickness. The Radial Chip Thinning Factor corrects for this:

RCTF = √( D / (2 × ae) )

Multiply your manufacturer's recommended fz (for half-slot engagement) by the RCTF to find the feed you should actually program. The result maintains the correct chip thickness at the lower radial engagement.

For a full explanation with worked examples, see Chip Thinning & High-Efficiency Milling Explained.

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