When does the changeover clock start and stop?

At the last part of the previous run and the first good part of this one. Lean practice measures it that way, so setup scrap and trial parts fall inside it.

How many parts does a changeover cost me?

The parts the cell would make at full cycle rate in that time. At the defaults, 20 minutes costs 171 parts, 6.7% of the window, and a smaller batch pays a larger share.

What cycle time per part do I use with a multi-part fixture?

Divide the cell cycle time by the parts each cycle finishes. A 28 sec cycle on a four-part fixture is 7 sec per part, the default here.

How many parts should I start to get the batch quantity?

Batch quantity ÷ first-pass yield. For 2,000 good parts at 97% yield, start about 2,062; the time needed row already allows for those extra cycles.

Robotics & Automation calculator

Robot Batch Capacity Calculator

Check whether a batch will finish in its scheduled window once the changeover, stops and rejects are paid for. You need the batch quantity, window, changeover time, cycle time per part, availability and first-pass yield.

What this calculator does

Good parts a robot cell makes in a batch window after changeover, stops and rejects, and whether the batch quantity fits.

Formula used

Parts at full cycle rate = batch window × 60 ÷ cycle time per part; lost to changeover = changeover time × 60 ÷ cycle time per part
Run parts = full-rate parts − changeover loss; lost to stops = run parts × (100 − availability) ÷ 100
Lost to rejects = run parts × availability × (100 − yield) ÷ 10,000; good parts = run parts × availability × yield ÷ 10,000
Time needed = changeover time + batch quantity × cycle time per part ÷ 60 × 10,000 ÷ (availability × yield)
Margin to the window = batch window − time needed

Inputs explained

Batch Quantity: Good parts the order or kanban needs from this batch.
Batch Window: Minutes scheduled for this batch, changeover included, breaks excluded.
Changeover Time: Last part of the previous run to the first good part.
Cycle Time per Part: Cell cycle time ÷ parts per cycle, timed while the cell runs.
Availability: Run time ÷ planned time, changeovers left out, from the stop log.
First-Pass Yield: Parts good first time ÷ parts made, from inspection records.

How to use the result

Best suited to promising a ship date for a batch, setting a changeover target for small batches.
Assumes full-rate cycles from the first good part; a slow ramp after the changeover lowers output below this estimate.

Current U.S. benchmarks

Global copper trades at $13,543 per tonne (IMF via FRED, Jul 2026), up 38.6% in a year, and U.S. industrial electricity averages 9.77 cents per kWh. Both feed electrified-hardware unit economics.

Common questions

When does the changeover clock start and stop? At the last part of the previous run and the first good part of this one. Lean practice measures it that way, so setup scrap and trial parts fall inside it.
How many parts does a changeover cost me? The parts the cell would make at full cycle rate in that time. At the defaults, 20 minutes costs 171 parts, 6.7% of the window, and a smaller batch pays a larger share.
What cycle time per part do I use with a multi-part fixture? Divide the cell cycle time by the parts each cycle finishes. A 28 sec cycle on a four-part fixture is 7 sec per part, the default here.
How many parts should I start to get the batch quantity? Batch quantity ÷ first-pass yield. For 2,000 good parts at 97% yield, start about 2,062; the time needed row already allows for those extra cycles.

Last reviewed 2026-10-01.