How do you calculate power module rework rate?

Divide the number of power modules requiring rework by the total modules built or tested, then multiply by 100. With 8 modules reworked out of 250, that is 8 ÷ 250 × 100 = 3.2%.

What is a good rework rate for power modules?

On a mature IGBT or SiC module line, sustained first-pass rework below 2-3% is typical world-class; the 3.2% in our example sits just above that band and leaves a comfortable 91.8-point margin under a 95% target ceiling.

Why is my power module rework rate climbing?

Common drivers are solder voiding under the baseplate, cracked or lifted wire bonds, poor thermal-paste coverage, and gate-driver misplacement. Trend the rate against a defect Pareto to isolate which is dominating.

Rework rate vs scrap rate — what's the difference?

Rework rate counts modules that can be recovered by additional work; scrap rate counts modules discarded entirely. A high rework rate with low scrap means defects are recoverable but your process is still not right-first-time.

Does rework hurt power module reliability?

It can. Reflowing solder joints or re-bonding wires adds thermal cycles and mechanical stress, which is why many aerospace and EV programs cap allowable rework touches per module.

How many modules should I sample before trusting the rate?

With small lots the percentage is noisy; 8 out of 250 is meaningful, but a rate from fewer than ~50 modules can swing several points on a single defect.

Power Electronics, Motors & Drives calculator

Power Module Rework Rate Calculator

Power module rework rate is the share of assembled or tested power modules — IGBT stacks, SiC half-bridges, driver-integrated modules — that fail first-pass inspection and must be reworked before shipping. Power electronics process engineers and SMT quality leads track it because rework on a bonded, potted, or baseplate-soldered module is expensive and often introduces reliability risk. A rising rework rate points to solder void issues, wire-bond defects, thermal interface problems, or gate-driver assembly errors. It is one of the cleanest leading indicators of process health on a power module line.

What this calculator does

Calculate power module rework rate from modules needing rework, total modules built or tested, and the target rework limit.
Use it when tracking rework from wire bond, solder void, substrate attach, partial discharge, thermal interface, or electrical test defects.
It computes the percentage of power modules that required rework out of all modules built or tested, plus the point gap to your target maximum.

Formula used

Power module rework rate = power modules requiring rework ÷ total power modules built or tested × 100
Power module rework gap to target = target maximum rework rate - power module rework rate

Inputs explained

Power modules requiring rework:
Total power modules built or tested:
Target maximum rework rate:

How to use the result

Use it at end-of-shift or per production lot to trend first-pass quality on a power module assembly or test line.
It counts modules touched by rework but says nothing about defect type or whether rework restored full reliability — pair it with a Pareto of failure modes.

Current U.S. benchmarks

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The U.S. has 11,261 computer and electronic products establishments employing about 815,443 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate power module rework rate? Divide the number of power modules requiring rework by the total modules built or tested, then multiply by 100. With 8 modules reworked out of 250, that is 8 ÷ 250 × 100 = 3.2%.
What is a good rework rate for power modules? On a mature IGBT or SiC module line, sustained first-pass rework below 2-3% is typical world-class; the 3.2% in our example sits just above that band and leaves a comfortable 91.8-point margin under a 95% target ceiling.
Why is my power module rework rate climbing? Common drivers are solder voiding under the baseplate, cracked or lifted wire bonds, poor thermal-paste coverage, and gate-driver misplacement. Trend the rate against a defect Pareto to isolate which is dominating.
Rework rate vs scrap rate — what's the difference? Rework rate counts modules that can be recovered by additional work; scrap rate counts modules discarded entirely. A high rework rate with low scrap means defects are recoverable but your process is still not right-first-time.
Does rework hurt power module reliability? It can. Reflowing solder joints or re-bonding wires adds thermal cycles and mechanical stress, which is why many aerospace and EV programs cap allowable rework touches per module.

Last reviewed 2026-05-12.