Cutting optimisation: less waste, lower labour cost or a simpler saw sequence?
A good cutting plan must fit the requested parts into available stock. A useful workshop plan must also be practical to execute. Saving a few centimetres of tube can lose its value if the operator spends extra time changing the stop, checking a mitre, moving a long section or finding the next part.
Packing and sequencing answer different questions
The packing problem asks which pieces share each stock length, allowing for kerf, end trim and geometry. The sequencing problem asks in what order the feasible operations should happen. An efficient bar diagram can still involve awkward work at the machine.
A heuristic searches for useful candidates without examining every possible arrangement. LEVRTEK uses bounded candidate comparison and heuristic results; it does not prove the globally best plan for every job. Review the proposal against the stock, drawing and workshop setup.
LEVRTEK’s “Least waste” choice compares material loss: input stock minus checked finished material, including kerf, trims and remainder. Reusable remnants are reported separately, not silently deducted from that objective. “Lowest total cost” combines input material cost with complete estimated workshop time, including measuring, cutting, setups and handling. “Balanced” trades material waste against estimated handling time across candidates. Less handling can still mean more total time when extra measuring or saw setup is needed. Estimates are provisional until they reflect your shop; available controls depend on the entry point you use.
Choose the priority for this job
Scarce stock, a mixed repair job and repeated frames can call for different choices. Make the trade-off explicit before comparing plans.
- Material first: compare full stock input, finished material, kerf, trims and remainder. A reusable offcut has potential value, but somebody must identify and reuse it.
- Labour and handling first: count loading, measuring, stop moves, angle changes, turning parts, parking unfinished work, reloading and sorting. Blade-on-material time alone is incomplete.
- Simplicity first: finishing a bar or a complete kit can be easier to check than an interleaved schedule. This is workshop judgement, not a claim of a dedicated LEVRTEK simplicity algorithm.
Move the stop, change the angle or turn the part?
These are different operations. A repeated stop position can reduce measuring. An angle change needs setup and verification. Turning a part may preserve a saw setting but add a lift, an end-for-end move, a changed datum and another clamp/check cycle. A heavy or long section may make that alternative slower or unsuitable.
Festool documents repeat-length stops for its listed compatible saws. KALTENBACH describes angle adjustment, clamping and positioning equipment on its KBS 1001. Those examples show why the actual machine matters; they are not instructions for rotating heavy stock or bundle cutting on another saw. Use the machine manual and approved support and clamping method.
Source context: Festool WA-AR repeat-length stop: listed machine compatibility · KALTENBACH KBS 1001: angle, clamping and positioning equipment
Cut all the first ends, then the second ends?
A first-end batch can reduce angle changes on matching pieces. It also creates unfinished parts that must be identified, parked, moved back, aligned and checked. Leave enough verified material for the second operation and preserve the correct datum and handed ends. A finished-length list alone is not an instruction for sizing unfinished blanks.
Compare a small controlled batch with finishing each piece or kit. Fewer setups can help when changing the machine is costly and pieces are easy to handle. Extra movement, checking and queue time can remove that saving. Measure the complete operations rather than assuming batching always wins.
A fictional material-versus-labour comparison
Fictional teaching example — static illustrative data, not a customer job, measured saving or calculated app result.
Assume both plans fulfil the same demonstration job. Stock quantities and durations are assumed feasible for teaching the arithmetic; this is not an allocation proof or optimiser benchmark. Each bar costs A$48 and the shop rate is A$75/hour. Other costs are excluded.
| Plan | Input stock | Execution | Material | Labour / handling | Gross comparison |
|---|---|---|---|---|---|
| A: conserve material | 4 bars | 80 min | A$192 | A$100 | A$292 |
| B: repeated run | 5 bars | 35 min | A$240 | A$43.75 | A$283.75 |
Use the whole cost, and check the assumptions
Plan B spends A$48 more on material and saves 45 minutes. At A$75/hour, that saves A$56.25 in labour, so the gross comparison is A$8.25 lower. The break-even rate is A$48 ÷ 0.75 hour = A$64/hour. Below that rate, Plan A costs less under these assumptions.
Compare full input-stock cost plus complete execution minutes × hourly rate ÷ 60. Missing costs are unknown, not zero. Keep potential remnant reuse and scrap recovery separate from this gross comparison. Use a labour/resource basis that fits the shop: unattended machine minutes and two-person beam handling need not cost the same.
Check demand fulfilment, material, usable lengths, kerf, trims, signed ends and datum before comparing scores. Then time a real job and replace provisional setup and handling assumptions with observations. Quality and safe handling remain constraints.
Sources and scope
This is a research-based workshop guide. Supplier charts and software documentation apply to their named products and contexts; confirm current details before relying on them.