KEVOS® MAKEOS · Manufacturing
Turning Cut Planner (Speed, Power, Torque, Finish and Time)
What spindle speed, power and torque does this turning cut need, what surface finish will the feed and nose radius give, and how long will it take?
Plan of a turning operation: spindle speed from cutting speed and diameter (held to the machine’s maximum), passes for the radial stock at the depth of cut, cutting force and power from the specific cutting force (as the turning power tool), spindle torque against the machine’s torque at that speed, theoretical peak-to-valley height and roughness from feed and nose radius (as the turning cusp tool), and cutting time (as the turning time tool).
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Work diameter | mm | Starting diameter of the work. |
| Length of cut | mm | Length turned in each pass. |
| Approach and overrun | mm | Extra travel for approach and run-out. |
| Radial stock to remove | mm | Material to remove on the radius. |
| Depth of cut | mm | Depth of cut per pass. |
| Cutting speed | m/min | Cutting speed for the tool and material. |
| Feed | mm/rev | Feed per revolution. |
| Nose radius | mm | Tool nose radius. |
| Specific cutting force | N/mm² | Specific cutting force for the material at this chip thickness (your value; see the chip thickness tool). |
| Machine efficiency | % | Share of motor power that reaches the cut. |
| Spindle power | kW | Rated spindle power. |
| Largest spindle speed | rpm | Highest spindle speed of the machine (or of the chuck and work). |
| Spindle torque available at this speed | N·m | Torque the spindle can deliver at this speed (from the power-torque chart). |
| Largest roughness Ra wanted | µm | Roughness the drawing allows. |
Method and formulas
- n = 1000 v_c ÷ (π D), limited to n_max (the cutting speed then falls); passes = stock ÷ a_p rounded up.
- F_c = k_c a_p f; power = F_c v_c ÷ 60 000 ÷ η; torque = F_c D ÷ 2000 (as the turning power tool).
- Peak-to-valley R_t ≈ f² ÷ (8r); Ra ≈ f² ÷ (32r) (as the turning cusp tool).
- Time = passes × (L + approach) ÷ (f n) (as the turning time tool).
- Example: 200 m/min on 80 mm runs at 795.77 rpm and needs 6.25 kW; Ra is about 2.4414 µm and the cut takes 1.0254 min.
Limitations
- Uses the starting diameter for every pass; later passes are slightly lighter.
- Theoretical finish only; vibration, built-up edge and tool wear make it rougher.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Plan speeds and feeds for a turned part
- Check a heavy cut against spindle power and torque
- Choose a feed for a required finish
Who it is for
- CNC machinists
- Process planners
- Manufacturing engineers
What you get
- Spindle speed and passes
- Cutting force, power and torque
- Theoretical finish and cutting time
Interpreting the result
- Halving the feed quarters the theoretical roughness but doubles the time.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1084–1101, 1023–1030. Topic reference; no source tables or recommended settings are reproduced.
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Open the Turning Cut Planner (Speed, Power, Torque, Finish and Time) calculator
