Quality Plan for Pneumatic Valve Body: First Article, Inspection and Zero Defects

The quality plan behind a zero-defect delivery of a brass or aluminium body for automation equipment: the control plan, in-process controls, final verification and the result recorded at the customer's goods-in.

The quality requirement

The customer required a documented control plan, a first article inspection and evidence of capability for a brass or aluminium body for automation equipment.

The specification, bore roundness within 0.01 mm for seal life, defined which characteristics were critical and therefore which ones needed measurement rather than a visual check.

The control plan

We wrote a control plan linking each critical characteristic to a process step, a measuring method, a sample size and a reaction plan.

Operators and inspectors work from the same document, which removes the usual disagreement about what has to be checked.

In-process controls

First-off approval, in-process patrol inspection and a defined response to any trend towards a limit were built into the routine.

On-machine probing caught drift before parts were finished, so scrap was prevented rather than sorted out afterwards.

Final verification

Final inspection covered every characteristic on the drawing that could not be verified in process, reported against the model with measurement uncertainty stated.

Material certificates, heat treatment records and finishing records were attached to the shipment documentation.

Result at goods-in

The delivery passed incoming inspection with zero defects, and the customer reduced its own inspection level for subsequent batches.

The control plan is reviewed at every drawing revision, which keeps the quality record as current as the part.

Summary

Every figure quoted here came from the inspection report supplied with the shipment, not from an estimate made at quotation stage.