Radial Chip Thinning Feed Compensation
The feed correction for a light radial cut.
Example
You enter
- Radial width of cut ae (in) 0.05
- Cutter diameter D (in) 0.5
- Target chip load fz (in/tooth) 0.004
You get
- Radial chip thinning factor 1.667
- Compensated feed per tooth 0.0067 in/tooth
Checked against published worked examples from: Harvey Performance Company.
Details, formula, and sources
ScopeBelow half the cutter diameter the chip comes out thinner than the programmed feed per tooth, so RCTF = 1/(2 sqrt((ae/D) - (ae/D)^2)) raises the feed to restore the intended chip load. At 10% radial engagement RCTF 1.667 (feed two-thirds higher); at half immersion RCTF 1.0, the crossover where compensation stops. The basis of high-feed and trochoidal milling, and the difference between a light pass that rubs and one that cuts. Radial thinning only. A shop aid; the tool maker's chip load governs.
Formula or tabler = ae/D; RCTF = (r < 0.5) ? 1/(2 sqrt(r - r^2)) : 1.0; fz_prog = fz_target x RCTF.
Source and editionThe radial-chip-thinning geometry - the chip thinning factor RCTF = 1/(2 sqrt((ae/D) - (ae/D)^2)) for ae below half the cutter diameter and the compensated feed - as compiled in the modern milling and Machinery's Handbook references, by name.
Free accessThe radial chip thinning relation is a public cutting-geometry result in the modern milling references and tool-maker guidance.
What governsEstimate. AHJ and licensed professional govern.
API field namesae_in, d_in, fz_target, rctf, fz_prog
- Thinning factor RCTF = 1/(2 sqrt((ae/D) - (ae/D)^2)) at light radial engagementmilling geometry
- Compensated feed fz_prog = fz_target x RCTF restores the intended chip thicknessmilling practice
- Crossover RCTF = 1.0 at and above half immersion (ae >= D/2)radial-thinning geometry