Closed-Loop Tolerance Allocation: Linking Process Capability (Cpk) with Critical-to-Quality (CTQ) Engineering Drawings

Abstract: Connecting plant-floor manufacturing capability databases directly to CAD tolerance authoring tools to eliminate unmanufacturable engineering designs.

1. The Disconnect between Design and Manufacturing Design engineers frequently specify tight ±0.05mm tolerances in CAD without knowing the true historical capability of plant machinery, leading to costly tooling redesigns during Phase 4 of APQP.

2. Closed-Loop Capability Synthesis ADM Charts integrates live SPC databases into CAD authoring environments. When a tolerance is assigned to a feature, the software cross-references plant Cpk records, calculating the exact probability of non-conformance and suggesting cost-neutral design modifications before tooling kickoff.