Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Manufacturing systems

Scrap rate

Also known as: Scrap ratio, Reject rate

German: Ausschussquote

In manufacturing, the scrap rate is the proportion of produced units or material that fails quality requirements and cannot be reworked, and is therefore discarded or recycled.

  • Manufacturing systems
  • Standards

In one sentence

The scrap rate is the share of produced units or material that fails requirements, can't be reworked and is discarded.

Example

Of 5,000 castings, 150 are scrapped because of porosity, which gives a scrap rate of 3 percent.

How it applies

  • Operation: Scrap is recorded with defect codes per order and shift; the scrap rate is a standard KPI. ISO 22400-2 defines a scrap ratio among its KPIs for manufacturing operations management.
  • Cost and sustainability: Scrap wastes material, energy and capacity. Reducing it improves cost and environmental performance.
  • Improvement: Scrap analysis by defect, machine and shift points to root causes such as Tool wear, material issues or settings.
  • Documentation: Define the counting basis (units, weight, value) and whether start-up scrap is included. Scrap handling instructions should cover segregation, marking and disposal, so scrapped units can't re-enter the flow by mistake.

Scrap rate vs. first-pass yield

The scrap rate counts what is lost. First-pass yield (FPY) counts what is right the first time, so it also reflects rework.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: ISO 22400-2:2014, Automation systems and integration — Key performance indicators (KPIs) for manufacturing operations management — Part 2: Definitions and descriptions

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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