defectiveunit

In quality assurance and manufacturing, a defectiveunit is a single product unit that fails to meet defined quality specifications or performance criteria. The term is used to identify items that should not proceed to customers and are subject to disposition within a batch or lot. A defectiveunit is typically detected during incoming inspection, in-process testing, final acceptance testing, or after field use.

Defectiveunits arise from various causes, including design flaws, manufacturing errors, substandard materials, process variability, or handling damage. They are commonly classified by the severity of impact as critical, major, or minor defects, which guides the required corrective action.

Detection and handling involve isolation or quarantine of suspected defectiveunits, followed by diagnostic testing to confirm failure mode. If possible, the item is repaired or reworked; otherwise it is scrapped. Lot traceability and serial numbering enable root-cause analysis and prevent recurrence.

Quality metrics track defectiveunits as part of yield and reliability analysis. Key indicators include defect rate, defective units per million opportunities (DPMO), and first-pass yield. Corrective actions (CAPA) address underlying causes, while supplier quality management targets failures sourced from components or materials.

In practice, the term is used across industries such as electronics, consumer goods, and medical devices, and has an analogous concept in software where a defective build or release represents a failure to meet functional requirements.

See also: defect rate, yield, quality control, reliability engineering, CAPA, traceability.