Measure the result. Compare it to the requirement.
Quality inspection verifies whether manufactured components, assemblies, materials, surfaces, documentation, and functional characteristics conform to defined acceptance requirements.
A measurement becomes meaningful only when it is compared against a defined requirement.
Different product characteristics require different forms of verification.
Dimensional Inspection
Calipers, micrometers, gauges, height instruments, optical systems, and other tools verify physical dimensions.
Coordinate Measurement
Coordinate measuring machines can evaluate complex geometry, feature location, profiles, datums, and geometric relationships.
Visual Inspection
Appearance, damage, burrs, contamination, finish, assembly condition, labeling, and workmanship can be evaluated visually.
Functional Testing
Assemblies may be operated or loaded to verify electrical, mechanical, pressure, flow, movement, or other performance.
Material Verification
Hardness, chemistry, certification, coating thickness, heat-treatment condition, or other material properties may require verification.
Nondestructive Examination
Selected applications may use penetrant, magnetic, ultrasonic, radiographic, or other methods to identify discontinuities.
Inspection should focus on the characteristics that control product acceptance.
Separate functional, safety, mating, cosmetic, and process-critical requirements from general dimensions.
Select gauges and equipment capable of resolving the tolerance and geometry being evaluated.
Determine whether requirements call for first article, in-process, final, sampling, or 100 percent inspection.
Operators and inspectors need current drawings, specifications, standards, samples, or test limits.
Establish how rejected, questionable, reworked, or concessioned product is identified and controlled.
A tighter tolerance requires more than a more expensive measuring instrument.
The complete measurement system includes the instrument, calibration, fixture, environment, measurement method, operator, datum strategy, and repeatability of the inspection process.
Documentation connects the inspected product to the evidence of conformity.
First Article Inspection
Initial production may be measured in greater detail before recurring manufacturing is released.
Inspection Reports
Recorded measurements can document critical dimensions, test results, lots, quantities, and acceptance status.
Traceability
Serial numbers, heat numbers, lot identifiers, material records, or production records can connect finished parts to their history.
Corrective Action
Nonconforming results may require containment, root-cause analysis, process correction, and verification of effectiveness.
Inspection starts with a clear specification.
Drawings, tolerances, materials, finishes, revision control, and acceptance requirements should be defined before a supplier begins production.
Manufacturing Drawings & Specifications →