Process Capability Concepts

What this topic covers

Compare stable process variation with engineering specification width.

Core testing ideas

Capability indices summarize how process distribution relates to specification limits.

Capability analysis assumes the underlying data and process conditions are appropriate for the calculation.

A high index does not excuse poor measurement systems or unstable processes.

Measurement and method limits

SPC and capability metrics describe process behaviour, while engineering specifications describe product requirements.

Evidence and traceability

Nonconformance, corrective action, audits and supplier controls close the loop when results do not meet expectations.

Using the result

Quality metrics should be defined consistently so improvement is real rather than a reporting artifact.