BIZOMAT MAKEOS · Manufacturing
Turning Feed and Cutting Time
How long will a straight turning pass take?
Calculate axial feed, ideal straight-pass time and surface speed for constant-RPM turning.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Spindle speed | rpm | Actual machine setting, checked against tooling and machine limits. |
| Feed per revolution | mm/rev | Programmed feed per revolution for the tool and material. |
| Feed travel | mm | Total distance travelled at the entered feed, including any chosen approach and overtravel. |
| Number of equal passes | passes | Passes with the same travel and feed; enter dissimilar passes separately. |
| Cutting diameter | mm | Diameter at which the reported surface speed is evaluated. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Spindle speed
- What it is
- The constant spindle speed of the lathe during the passes.
- Units and format
- Enter a number in rpm: revolutions per minute. The form accepts 0.001 rpm to 1000000 rpm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1000 rpm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Axial feed rate is directly proportional to rpm, so time falls as it rises.
- Get it right
- Constant surface speed mode changes rpm with diameter; this tool assumes rpm stays fixed.
What this means: Feed per revolution
- What it is
- How far the tool moves along the part for every revolution of the spindle, as programmed.
- Units and format
- Enter a number in mm/rev: millimetres per revolution. The form accepts 0.000001 mm/rev to 100 mm/rev. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 0.2 mm/rev as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Cutting time is inversely proportional to feed per revolution.
- Get it right
- Do not enter mm/min; feed per revolution times rpm gives mm/min.
What this means: Feed travel
- What it is
- The distance the tool travels at cutting feed in each pass, including any approach and overtravel you choose to count.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 100 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Time per pass is directly proportional to feed travel.
- Get it right
- Use the travel for one pass; the number of passes multiplies it.
What this means: Number of equal passes
- What it is
- How many passes of the same travel and feed are made, such as roughing passes at successive depths.
- Units and format
- Enter a number in passes: passes. The form accepts 1 passes to 10000 passes. Use a whole number. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 3 passes as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Total cutting time is directly proportional to the number of passes.
- Get it right
- Calculate finishing passes with a different feed or length separately.
What this means: Cutting diameter
- What it is
- The workpiece diameter at which you want the surface speed reported, usually the largest diameter being cut.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 50 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Surface speed is directly proportional to this diameter.
- Get it right
- It only affects the reported surface speed, not the cutting time.
Method and formulas
- Axial feed = RPM × feed per revolution.
- Total cutting time = passes × travel ÷ axial feed.
- Surface speed = π × diameter × RPM ÷ 1000. Example: 100 mm at 1000 rpm and 0.2 mm/rev takes 0.5 min per pass, or 1.5 min for three passes.
Limitations
- Constant RPM and axial passes only; excludes facing and constant-surface-speed integration.
- Return, loading, acceleration and tool changes are not included.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- lathe time
- turning cycle
- axial feed
Who it is for
- Machinists
- Estimators
What you get
- Axial feed
- Time per pass
- Total cutting time
- Surface speed
Interpreting the result
- Use each pass’s actual diameter for surface speed and add handling time to the estimate.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1015, 1025, 1153. Topic reference; no source tables or recommended settings are reproduced.
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