KEVOS® MAKEOS · Manufacturing
Finish Turning Set-up (Feed for Finish, Nose-Radius Compensation, Time)
What feed gives my surface finish with this insert nose radius, how much does the nose radius distort a chamfer or taper if not compensated, and how long is the finishing pass?
Set-up of a finish-turning pass: the feed for a target Ra from the nose radius (as the feed for finish tool) or the Ra of a feed you choose, spindle speed from the cutting speed held to the machine maximum, cutting time for the pass (as the turning time tool), and the Z and X compensation and the profile error for a chamfer or taper at your angle if nose-radius compensation is not used (as the nose radius compensation tool).
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Nose radius | mm | Nose radius of the finishing insert. |
| Ra wanted | µm | Surface roughness the drawing requires. |
| Feed chosen (0 = feed for the target) | mm/rev | Feed you intend to program; 0 uses the feed for the target Ra. |
| Cutting speed | m/min | Cutting speed for finishing. |
| Finished diameter | mm | Diameter being finished. |
| Length turned | mm | Length of the finishing pass. |
| Approach and overrun | mm | Extra travel for approach and run-out. |
| Largest spindle speed | rpm | Highest spindle speed. |
| Chamfer or taper angle | ° | Angle of the chamfer or taper to the axis that the tool also cuts. |
| Largest uncompensated profile error | mm | Largest error on the chamfer or taper you accept without nose-radius compensation. |
Method and formulas
- Ra ≈ 0.0316 f² ÷ R (in µm with f and R in mm × 1000), so f = √(Ra R ÷ 31.55) (as the feed for finish tool); R_t = f² ÷ 8R.
- n = min(1000 v_c ÷ π D, n_max); time = (L + approach) ÷ (f n) (as the turning time tool).
- For angle θ: ΔZ = r [1 − tan(θ ÷ 2)], ΔX = r [1 − tan((90° − θ) ÷ 2)]; profile error = r (sin θ + cos θ − 1) (as the nose radius compensation tool).
- Example: Ra 1.6 µm with r 0.8 mm needs 0.20141 mm/rev; the pass takes 15.348 s; uncompensated, the 45° chamfer is off by 0.33137 mm.
Limitations
- Theoretical finish; vibration, built-up edge and wear make it rougher.
- Straight chamfers and tapers; arcs need full compensation.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Set feeds for a finishing pass
- Check a chamfer error before enabling compensation
- Estimate finishing time
Who it is for
- CNC machinists
- CNC programmers
- Process planners
What you get
- Feed for the target and Ra at the feed used
- Spindle speed and finishing time
- Nose-radius compensation and profile error
Interpreting the result
- A larger nose radius allows a higher feed for the same finish but raises cutting forces and chatter risk.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1125–1131, 782–790. Topic reference; no source tables or recommended settings are reproduced.
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Open the Finish Turning Set-up (Feed for Finish, Nose-Radius Compensation, Time) calculator
