How do you calculate reject station capacity?

Multiply handling positions by cycles per position-hour for gross capacity, then multiply by uptime and disposition rate. Here 2 × 180 × 0.92 × 0.98 gives about 324.6 good rejects cleared per hour.

Why isn't gross capacity the real capacity?

Gross capacity assumes the station never stops and never mis-handles a part. After 92% uptime and 98% correct disposition, the 360 gross drops to roughly 324.6 parts per hour you can actually rely on.

What happens if reject capacity is too low?

Rejected parts accumulate, the reject conveyor blocks, and the main line stops because it has nowhere to divert defects. Reject capacity should comfortably exceed your peak reject generation rate, not just the average.

What is disposition rate in reject handling?

It is the share of rejects the station correctly sorts, diverts, scraps, or routes to rework. At 98%, about 6.6 parts per hour in this example are not dispositioned correctly and need manual recovery.

How much reject capacity headroom should I plan for?

Size for your worst credible defect burst, often 2-3x the steady reject rate, because rejects arrive unevenly. A station sized only to the average will block during quality excursions.

Reject station capacity vs main line throughput — how do they connect?

Reject capacity must keep pace with the rejects the main line produces. If the line runs 1,000 parts/hr at a 5% reject rate, you need to clear 50/hr — well under this station's 324.6, leaving healthy margin.

Conveyors calculator

Reject Station Capacity Calculator

Reject station capacity is the number of rejected parts per hour your reject-handling stations can actually clear and correctly dispose of. Line engineers size this so the reject path never becomes the bottleneck that blocks the main conveyor when defect rates spike. The calculation starts from raw mechanical throughput, then derates for the time the station is down and for rejects that aren't correctly sorted, diverted, or removed. If reject capacity falls below the rate at which the line generates rejects, parts back up and the whole line stalls — making this a quiet but critical constraint.

What this calculator does

Estimate how many rejected parts a reject, inspection, or diversion station can process per hour.
a quality or automation engineer needs to confirm that a reject station will not become a bottleneck
It computes the good (correctly dispositioned) reject-handling capacity per hour after derating gross capacity for uptime and disposition accuracy.

Formula used

Gross reject station capacity = positions × cycles per position-hour
Good reject disposition capacity = gross capacity × uptime × disposition rate

Inputs explained

Active reject handling positions:
Reject cycles per position-hour:
Reject station uptime:
Successful reject disposition rate:

How to use the result

Use it when sizing a reject diverter or sortation cell, or when investigating whether a backed-up reject path is blocking the main line.
It assumes a steady reject arrival pattern; bursty defect events can overwhelm a station whose average capacity looks adequate.

Current U.S. benchmarks

The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate reject station capacity? Multiply handling positions by cycles per position-hour for gross capacity, then multiply by uptime and disposition rate. Here 2 × 180 × 0.92 × 0.98 gives about 324.6 good rejects cleared per hour.
Why isn't gross capacity the real capacity? Gross capacity assumes the station never stops and never mis-handles a part. After 92% uptime and 98% correct disposition, the 360 gross drops to roughly 324.6 parts per hour you can actually rely on.
What happens if reject capacity is too low? Rejected parts accumulate, the reject conveyor blocks, and the main line stops because it has nowhere to divert defects. Reject capacity should comfortably exceed your peak reject generation rate, not just the average.
What is disposition rate in reject handling? It is the share of rejects the station correctly sorts, diverts, scraps, or routes to rework. At 98%, about 6.6 parts per hour in this example are not dispositioned correctly and need manual recovery.
How much reject capacity headroom should I plan for? Size for your worst credible defect burst, often 2-3x the steady reject rate, because rejects arrive unevenly. A station sized only to the average will block during quality excursions.

Last reviewed 2026-05-12.