How do you calculate burn-in test capacity?

Multiply fixture positions per cycle by cycles per shift for gross capacity, then multiply by chamber uptime and first-pass yield. With 48 positions, 4 cycles, 88% uptime and 98% yield, gross is 192 and good fixtures cleared is about 165.6 per shift.

What is gross versus good burn-in capacity?

Gross capacity is the theoretical maximum — 48 positions times 4 cycles equals 192 fixtures. Good capacity discounts that for downtime and failures, landing at roughly 166 fixtures actually cleared as shippable in the example.

How many fixtures are lost to chamber downtime?

At 88% uptime, 12% of the 192 gross slots go unused — about 23 fixtures' worth of capacity lost per shift to the chamber being unavailable. Raising uptime is usually the highest-leverage fix.

How many fixtures fail burn-in here?

With 98% first-pass yield applied after uptime, roughly 3.4 fixtures per shift fail and are pulled for rework or scrap. That 2% is your infant-mortality catch rate — the whole point of burn-in.

What is a good first-pass yield for burn-in?

For mature LED fixtures, first-pass burn-in yield is usually 97–99.5%; the 98% here is healthy. A sudden drop signals a component lot or solder issue upstream, which is exactly why burn-in data is monitored as an early-warning signal.

How do I increase burn-in capacity?

Three levers: more rack positions or cycles raise gross capacity, higher uptime recovers lost slots, and better upstream quality lifts yield. Here, lifting uptime from 88% to 95% adds about 13 good fixtures per shift without touching the chamber design.

Lighting, LEDs & Electrical Fixtures calculator

Burn-In Test Capacity Calculator

Burn-in test capacity tells a lighting plant how many luminaires actually clear the burn-in chamber as known-good in a shift, after accounting for chamber availability and first-pass yield. Reliability and test engineers use it because burn-in — running fixtures under elevated voltage and temperature to weed out infant-mortality failures — is often the throughput bottleneck behind final assembly. The chamber has finite positions and a finite number of cycles per shift, and not every fixture survives. This calculator separates gross capacity from the good units that actually feed shipping, so you can see exactly where positions, downtime, and failures are eating into output.

What this calculator does

Calculate the effective burn-in test capacity for LED luminaires per shift by combining rack positions, available test cycles, oven or chamber uptime, and the percentage of fixtures passing burn-in without failure.
Use this when checking whether burn-in test capacity can keep up with production output, planning additional rack space or chambers, scheduling overtime for test bottlenecks, or confirming test throughput before a large order ships.
It computes the number of good fixtures cleared per shift from burn-in, after applying chamber uptime and first-pass yield to gross rack capacity.

Formula used

Gross burn-in capacity = fixture positions per cycle x cycles per shift
Good fixtures cleared = gross capacity x chamber uptime% x burn-in first-pass yield%

Inputs explained

Fixture positions per rack cycle:
Available burn-in cycles per shift:
Chamber uptime:
Burn-in first-pass yield:

How to use the result

Use it when sizing burn-in capacity against assembly throughput or diagnosing whether the chamber is the line's bottleneck.
It assumes full racks every cycle and a constant yield; partial loads, mixed fixture dwell times, and units sent for rework rather than scrap will change the real good-out figure.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
Industrial electricity averages 8.66 cents per kWh across the U.S. (EIA, Apr 2026), up 5.5% from a year earlier. Energy-intensive steps carry this directly into unit cost.
The U.S. has 5,397 electrical equipment and appliances establishments employing about 369,437 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate burn-in test capacity? Multiply fixture positions per cycle by cycles per shift for gross capacity, then multiply by chamber uptime and first-pass yield. With 48 positions, 4 cycles, 88% uptime and 98% yield, gross is 192 and good fixtures cleared is about 165.6 per shift.
What is gross versus good burn-in capacity? Gross capacity is the theoretical maximum — 48 positions times 4 cycles equals 192 fixtures. Good capacity discounts that for downtime and failures, landing at roughly 166 fixtures actually cleared as shippable in the example.
How many fixtures are lost to chamber downtime? At 88% uptime, 12% of the 192 gross slots go unused — about 23 fixtures' worth of capacity lost per shift to the chamber being unavailable. Raising uptime is usually the highest-leverage fix.
How many fixtures fail burn-in here? With 98% first-pass yield applied after uptime, roughly 3.4 fixtures per shift fail and are pulled for rework or scrap. That 2% is your infant-mortality catch rate — the whole point of burn-in.
What is a good first-pass yield for burn-in? For mature LED fixtures, first-pass burn-in yield is usually 97–99.5%; the 98% here is healthy. A sudden drop signals a component lot or solder issue upstream, which is exactly why burn-in data is monitored as an early-warning signal.

Last reviewed 2026-05-12.