Incoming quality control (IQC)
Incoming quality control inspects and tests materials received from suppliers before they're accepted into inventory or released to production. IQC serves as a gatekeeper, catching supplier quality issues before defective materials cause downstream problems in manufacturing or reach end customers.
Examples
Receiving inspection: An IQC technician inspects a shipment of precision components, checking dimensions against drawings, verifying material certificates, and conducting visual inspection. Conforming lots are released; nonconforming lots are quarantined for disposition.
Sampling inspection: For a high-volume commodity component with established supplier history, IQC samples according to an AQL (Acceptable Quality Level) plan. Statistical sampling provides reasonable confidence without inspecting every unit.
Skip-lot inspection: A supplier with excellent performance history graduates to skip-lot status, where IQC inspects only periodically rather than every shipment. This recognizes supplier reliability while maintaining oversight.
Definition
IQC intensity should be risk-based. Critical components, new suppliers, and items with quality history warrant thorough inspection. Proven items from reliable suppliers may qualify for reduced inspection or supplier certification programs.
IQC findings drive supplier quality management. Tracking defect rates by supplier and part number identifies performance issues. Sharing IQC data with suppliers enables their improvement and provides objective basis for performance discussions.
The cost of IQC must be balanced against the cost of quality problems. Thorough inspection is expensive but prevents downstream costs from production disruption, rework, scrap, and customer complaints. The right balance depends on defect probability and consequences.
Moving quality responsibility toward suppliers, through certification programs, source inspection, and supplier development, can reduce IQC burden while maintaining quality. This requires supplier capability and trust developed through performance history.
Frequently asked questions
What is incoming quality control?
Incoming quality control (IQC) inspects and tests materials received from suppliers before they are accepted into inventory or released to production. IQC serves as a gatekeeper, catching supplier quality issues before defective materials cause downstream problems in manufacturing or reach end customers.
How much incoming inspection is the right amount?
IQC intensity should be risk-based. Critical components, new suppliers, and items with quality history warrant thorough inspection, while proven items from reliable suppliers may qualify for reduced inspection or supplier certification programs. The cost of inspection must be balanced against the cost of quality problems, which depends on defect probability and consequences: thorough inspection is expensive, but it prevents production disruption, rework, scrap, and customer complaints.
What is skip-lot inspection?
Skip-lot inspection is a status where a supplier with excellent performance history is inspected only periodically rather than on every shipment. Between full and skip-lot inspection sits AQL-based sampling, where statistical sampling of high-volume components with established history gives reasonable confidence without inspecting every unit. Both approaches recognize supplier reliability while maintaining oversight.
How does IQC data improve suppliers?
IQC findings drive supplier quality management. Tracking defect rates by supplier and part number identifies performance issues, and sharing that data with suppliers enables their improvement and gives performance discussions an objective basis. Moving quality responsibility toward suppliers through certification, source inspection, and supplier development can reduce the IQC burden, but that requires capability and trust built through performance history.
Previous
Next