In a regulated manufacturing environment, a nonconformance is any verified departure from an approved requirement, specification, or procedure. It can relate to product, process, documentation, or data.
Concrete examples of nonconformance
- Dimensional out-of-tolerance part: A CNC-machined aerospace bracket is inspected and one critical hole diameter measures 10.12 mm against a drawing requirement of 10.00 mm ± 0.05 mm. The characteristic is clearly out of tolerance, so the part is nonconforming and must be segregated and dispositioned.
- Wrong material used: A batch of medical device components is produced using stainless steel grade 304, but the approved bill of materials and material specification require 316L for corrosion resistance and biocompatibility. Even if the parts appear functional, they are nonconforming to the specification.
- Unapproved process route: An operator skips a required in-process inspection step documented in the work instruction because the line is behind schedule. The product may pass later checks, but the process deviation itself is a nonconformance that must be recorded.
- Using the wrong document revision: A technician builds an assembly using work instructions at Revision B, while the controlled document system shows Revision D as the current approved version. Any product built under the obsolete revision is nonconforming unless formally justified and accepted.
- Environmental or equipment setpoint out of range: A validated oven used for cure cycles runs at 185 °C for a lot, while the validated and documented setpoint is 200 °C ± 5 °C. Even if later tests look acceptable, the cure process is nonconforming to the qualified parameters.
- Labeling or traceability error: A pharmaceutical batch is labeled with an incorrect expiry date or missing lot number, breaking traceability requirements. The labeling defect is a nonconformance regardless of product quality.
Why context and systems matter
Whether an issue is treated as a nonconformance depends on how requirements are defined and controlled in your own systems: drawings, specifications, work instructions, MES routes, ERP master data, and QMS procedures. In brownfield plants with multiple legacy systems, misalignment between these sources is a common root cause of nonconformances.
Because equipment, software, and documentation are often validated and tightly controlled, even seemingly minor deviations (for example, using a not-yet-approved parameter change to reduce scrap) must be logged as nonconformances instead of treated as informal experiments. Replacement of systems just to “eliminate” nonconformances usually fails if requirements and change control are not cleaned up at the same time.
In all cases, the key is traceability: you need to be able to show which requirements were violated, how the nonconformance was detected, what the disposition was (scrap, rework, use-as-is with justification, concession), and what corrective and preventive actions, if any, were taken.
