The inspection before dispatch of coated or plated parts is a crucial step in the production process, which helps to verify that the work has been carried out in accordance with the relevant specification.
Visual Inspection for Coverage and Defects
Visual checks for coverage defects are performed on the complete part surface including edges, recesses, holes and surfaces that have been masked off. Coverage defects can appear as pinholes, bare spots, blistering and other forms of poor surface coverage.
Dimensional Checks After Coating
Thickness added by surface treatment can increase dimensions of a part. These additional dimensions must be allowed for in the pre-plate drawing. Dimensions of coated parts are inspected against those for the finished part, using, for example, a micrometer or CMM. This includes inspection of bore diameters, shaft diameters and mating faces.
Coating Thickness Measurement
Thickness gauges provide a direct reading of the deposited layer. For Surface Treatments, visit www.poeton.co.uk/surface-treatments/. Measurement of the coating thickness is crucial and depends on the accurate use of appropriate instruments, which are calibrated to recognised standards. Verification of the instruments is covered by UKAS
Adhesion Testing
Upon determination of failure via either test, all associated parts would be removed from service, either stripped and re-plated (in the case of adequate substrate) or destroyed. These determinations would then be documented, and the relevant cause investigated prior to continuation of part processing.
Documentation and Traceability
Documentation and Traceability. The finished parts are dispatched with a certificate of conformity, listing the processes involved, the specification, the thickness measurement results and the batch number. This enables traceability back to the processing of the batch.
When a Part Fails
A part that fails an inspection can be de-coated and re-coated depending on the substrate, otherwise it will be discarded from the process. The outcome of an inspection is logged against the relevant batch and any reason for failure investigated prior to processing further parts.
A clear inspection sequence protects both the processor and the customer, and gives dispatched parts the best chance of performing as intended.
