FIXTURE ECONOMICS / BATCH COST COMPARISON
Does the fixture earn its place?
Compare two workholding methods, see the batch economics and export a reviewable cost comparison.
Choose sequential or parallel processing and define how partially loaded batches are timed. Example inputs are editable; costs are expressed in CAD.
Read the engineering case study ↗01 / PRODUCTION ASSUMPTIONS
Compare the same demand.
Example values. The calculator applies the combined labor + machine rate to all elapsed setup and machining hours. It assumes full attendance; unattended machining or shared labor needs a different cost allocation.
OPTION A
The current method.
Machining time scales with the number of parts loaded.
Fixture investment is ignored for this strategy. Setup time applies to every loaded run, including the final partial run.
OPTION B
The proposed method.
Investment is included once in the total comparison. Setup time applies to every loaded run, including the final partial run.
02 / COST, CAPACITY & PAYBACK
Make the trade-off measurable.
| Measure | Conventional setup | Dedicated fixture |
|---|---|---|
| Loaded runs / last load | 500 / 1 parts | 125 / 4 parts |
| Setup hours | 25 | 6.25 |
| Machining hours | 50 | 20.833 |
| Operating cost | $6,750.00 | $2,437.50 |
| One-time investment | $0.00 | $2,000.00 |
| Total / cost per part | $6,750.00 / $13.50 | $4,437.50 / $8.88 |
Break-even is affected by batch boundaries.
First equal-cost quantity: none in checked range. First quantity where B is cheaper: 232. B remains cheaper from 234 through the checked limit of 5,000 parts. 3 changes of cost advantage were found; a first crossover is not permanent payback.
Calculation steps and interpretation
Full runs = floor(quantity / parts per run) Partial run = quantity mod parts per run Setup = loaded runs × setup minutes / 60 Sequential + single-part basis: machining = parts × cycle Parallel + single-part basis: one cycle per loaded run Loaded-batch basis: full cycle or prorated final run, as selected Operating cost = (setup hours + machining hours) × combined hourly rate Total = operating cost + effective one-time investment Net savings = total A − total B Net ROI = net savings / additional B investment × 100
Break-even reporting checks every integer quantity within the displayed range and accounts for changes at batch boundaries. Depreciation, tax, discounting, scrap, fixture maintenance and separate programming/inspection costs are outside this model.
Operating cost applies labor and machine charges over the same elapsed hours. Savings and break-even quantities depend on the costs, cycle times and batch rules you enter. Download calculation functions.