How kerf and end trim change a cutting plan
Kerf is the material removed by the blade. End trim reserves unusable material at the ends of a stock bar. Both must be included before a pattern can be called executable.
Updated: · Toreniva Cutwise technical reviewUse the same convention throughout the job
Cutwise accepts kerf in the same length unit as stock and demand. trimPerEnd applies to each end, so a value of 8 reserves 16 mm on every used stock bar. Keep drawing, machine and optimizer units aligned before comparing results.
Capacity check for one pattern
This is the current Cutwise API convention: a bar holding n pieces reserves max(n − 1, 0) kerfs. For one piece, the model reserves no between-piece kerf. End trim is a separate allowance at both ends, not another automatically counted saw cut.
Your shop may need additional cuts to separate a remnant, square an end or allow for clamping and tolerances. Check those operations before using the plan; the model's kerf count is not a statement that every machine uses the same procedure.
n = number of pieces on one stock bar
kerf allowance = kerf × max(n − 1, 0)
required length = sum(part lengths) + kerf allowance + (2 × trimPerEnd)
required length ≤ selected stock lengthCheck a boundary by hand
These are constructed arithmetic examples, not production tolerances or customer savings. Use one length unit throughout and verify the stock and cutting procedure before applying a boundary-tight plan.
| 6000 mm stock; 8 mm trim per end; 3 mm kerf | Required length | Model result |
|---|---|---|
| 2990 mm × 2 pieces | 5980 + 3 + 16 = 5999 mm | Fits with 1 mm left |
| 2991 mm × 2 pieces | 5982 + 3 + 16 = 6001 mm | Does not fit on one bar |
| 5984 mm × 1 piece | 5984 + 0 + 16 = 6000 mm | Fits only under the stated model convention |
Why a few millimetres can change the optimum
Near a stock-length boundary, adding one more cut or reserving end trim can force a part onto another bar. That is why utilization should be compared only when the underlying kerf and trim assumptions are identical.
| Scenario | Reserved trim | Kerf | Consequence |
|---|---|---|---|
| Idealized | 0 mm | 0 mm | May fit a pattern that cannot be cut |
| Trim only | 16 mm per bar | 0 mm | Less net stock on every used bar |
| Production input | 16 mm per bar | 3 mm | Patterns and utilization reflect process loss |
Review method and this update
The formulas here follow the public Cutwise API request documentation. The boundary examples are checked with integer length arithmetic; they do not demonstrate a particular machine's behavior. Updated September 12, 2026 to make the cut-count rule, hand checks and process limits explicit.