KEVOS® MAKEOS · Manufacturing
Turning Cut Power Check (Equivalent Chip Thickness, Cutting Forces, Power, Speed Limit)
Will this turning cut fit within the lathe’s spindle power, what forces does it put on the tool, and how fast could I run before the power runs out?
Check of a turning cut against the lathe: the chip area, equivalent chip thickness, removal rate, cutting force, feed-plane force and its axial and radial parts and the cutting power (as the equivalent chip thickness cutting forces tool), the highest cutting speed the spindle power allows for the same feed and depth (as the full-power cutting speed tool), and the spindle speed for the work diameter, against the power available and the spindle speed limit.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Feed per revolution | mm/rev | Feed per revolution. |
| Depth of cut | mm | Radial depth of cut. |
| Engaged cutting edge length | mm | Length of cutting edge in contact (from the tool nose radius, lead angle and depth). |
| Cutting speed | m/min | Cutting speed. |
| Specific cutting force at this ECT | N/mm² | Specific cutting force for the material at this equivalent chip thickness (from the tool maker). |
| Feed-plane force ÷ cutting force | Feed-plane force as a share of the cutting force. | |
| Chip flow angle | ° | Direction of chip flow, which splits the feed-plane force into axial and radial parts. |
| Lathe | ||
| Spindle motor power | kW | Rated spindle motor power. |
| Machine efficiency | % | Share of motor power that reaches the cut. |
| Work diameter | mm | Diameter being turned. |
| Spindle speed limit | rpm | Highest spindle speed of the lathe. |
Method and formulas
- Chip area = f a; ECT = area ÷ edge length; F_c = area × K_c; F_H = ratio × F_c split by the chip flow angle; power = F_c V ÷ 60 000 (as the equivalent chip thickness cutting forces tool).
- Power at the cut = motor × efficiency; highest speed = power at the cut × 60 000 ÷ (K_c a f) (as the full-power cutting speed tool).
- Spindle speed = 1000 V ÷ (π D).
- Example: the cut takes 12 kW of the 14.8 kW available, with 3,600 N cutting force; full power allows 246.67 m/min.
Limitations
- Specific cutting force must match the ECT and tool geometry used.
- Tool life, chatter and work holding limit the cut separately.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a roughing cut on a small lathe
- Find the fastest speed the motor allows
- Estimate tool and work forces for a setup
Who it is for
- Machinists
- CNC programmers
- Process planners
What you get
- Chip area, ECT and removal rate
- Cutting forces and power
- Power and speed against the lathe
Interpreting the result
- Thicker chips cut more efficiently: raising feed is a cheaper way to remove metal than raising speed.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1132–1141, 1084–1101. Topic reference; no source tables or recommended settings are reproduced.
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