KEVOS® MAKEOS · Manufacturing
Broaching Plan (Pitch, Teeth, Force, Broach Length and Time)
What tooth pitch and how many teeth does this broach need, what pull does it take, how long is the broach, and how long does each part take?
Plan of an internal or surface broaching operation: tooth pitch from chip space and machine capacity (as the broach pitch tool), teeth engaged at once, the cutting force from the rise per tooth, width of cut and specific cutting resistance, the number of cutting teeth for the stock plus finishing teeth, the toothed length and stroke, and the floor-to-floor time from cutting and return speeds.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Length of cut | mm | Length of the surface being broached in the direction of travel. |
| Total depth to remove | mm | Total depth of material removed. |
| Rise per tooth | mm | Increase in height from one cutting tooth to the next. |
| Finishing (sizing) teeth | Number of teeth at the end with no rise, for size and finish. | |
| Width of cut | mm | Width cut by each tooth. |
| Specific cutting resistance | N/mm² | Resistance per unit chip area for the material at broaching chip thicknesses (your value). |
| Chip packing factor | Ratio of gullet space to chip volume the tooth must hold (about 3–5). | |
| Machine pull capacity | t | Pull or push capacity of the broaching machine. |
| Approach and clearance travel | mm | Extra stroke for approach and clearance. |
| Machine stroke | mm | Longest stroke the machine allows. |
| Cutting speed | m/min | Cutting speed of the broach. |
| Return speed | m/min | Return speed. |
| Load and unload time | min | Time to load and unload a part. |
Method and formulas
- Pitch from chip space p = 3√(L × rise × F_p); pitch for capacity p = rise × L × b × k_c ÷ (9810 × capacity); the larger (and at least 5 mm) is used (as the broach pitch tool).
- Teeth engaged at most = ⌈L ÷ p⌉; force = teeth engaged × rise × b × k_c.
- Cutting teeth = stock ÷ rise (rounded up); toothed length = (cutting + finishing teeth) × p; stroke = toothed length + L + approach.
- Time = stroke ÷ v + stroke ÷ v_return + load time.
- Example: a 9.4868 mm pitch keeps 6 teeth cutting at 12 kN; the broach is 322.55 mm long and a part takes 0.38505 min.
Limitations
- Constant rise per tooth; progressive and rotor-cut broaches differ.
- Cutting resistance depends strongly on material, rise and sharpness.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Lay out a broach for a keyway, spline or flat
- Check a broaching machine’s pull and stroke
- Estimate broaching cycle time
Who it is for
- Tool designers
- Process planners
- Manufacturing engineers
What you get
- Tooth pitch and teeth engaged
- Cutting force against the machine
- Broach length, stroke and time per part
Interpreting the result
- A finer pitch puts more teeth in the cut, raising force but improving guidance and finish.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 980–990. Topic reference; no source tables or recommended settings are reproduced.
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Open the Broaching Plan (Pitch, Teeth, Force, Broach Length and Time) calculator
