Meaning
Formal engineering authorization procedures permit non-conforming manufactured components exceeding original drawing specification boundaries to accept use as-is or after minor rework. Tolerance relaxation occurs when engineering review boards confirm that minor dimensional variances will not impair product function, structural integrity, or assembly fit. Technical documentation requires formal engineering signature approvals before non-conforming parts release into active assembly lines.
Permanent drawing revisions follow if repeated tolerance expansions show no operational impact.
Concession Review
Quality control teams initiate formal material review board requests when manufactured parts fall outside design specification limits. Authorizing a tolerance relaxation requires stress analysis and mechanical fit evaluations by chief design engineers. Non-conforming part features receiving concession approval enter factory inventory without triggering complete batch scrap.
Quality records log approved concession decisions to track historical supplier capability trends.
Economic Justification
Scrapping complex machined components due to minor dimensional non-conformance imposes severe financial losses on manufacturing facilities. Applying tolerance relaxation prevents unnecessary production line halts and reduces scrap costs during initial pilot manufacturing runs. Engineering teams evaluate whether broadened tolerance limits maintain functional safety margins prior to signing concession waivers.
Concession approvals remain lot-specific unless technical drawings undergo official revision.
Quality Tracking
Manufacturing traceability systems log component serial numbers associated with approved concession waivers. Inspection records document exact dimensional deviations accepted during engineering review. Permanent drawing updates adjust baseline specifications when relaxed limits demonstrate complete reliability.
