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Supplier Quality & Incoming Inspection

Supplier & Incoming

Research-backed case study: AQL sampling, supplier scorecards, and defect containment.

Executive Summary

Incoming material defects were causing line stoppages and rework. This project implemented ANSI/ASQ Z1.4 (AQL) sampling plans for incoming inspection, built supplier scorecards (on-time delivery, defect rates, PPM) in Power BI, and established clear containment and escalation rules. Outcomes included ~35% reduction in incoming defect escapes, data-driven supplier reviews, and audit-ready inspection records.

~35% reduction in incoming defect escapes
Data-driven supplier reviews with scorecards
Audit-ready AQL inspection records

Context & Problem

Receiving inspection was inconsistent: some lots were 100% inspected, others skipped. Defects from suppliers reached the line and caused downtime. There was no single view of supplier performance, so poor performers were not systematically addressed. The organization needed standardized sampling (AQL), clear accept/reject criteria, and a way to track and present supplier quality to procurement and management.

Methodology & Frameworks

The approach used:

ANSI/ASQ Z1.4 - Sample size and Ac/Re from lot size, inspection level, and AQL. Major/minor defect classifications aligned with product requirements.
Supplier scorecards - Defect PPM, on-time delivery, and corrective action response time in one dashboard (Power BI) for management and procurement.
Containment and escalation - Rejected lots quarantined; repeat offenders escalated to supplier CAR and quality agreements.

Implementation

AQL plans were defined per part family and defect type. Inspectors used the same sampling table and recorded results in a shared system. Power BI dashboards pulled incoming data and supplier metadata to produce scorecards. Supplier review meetings used the scorecards to prioritize improvement and corrective action requests.

Outcomes

~35% reduction in defect escapes from incoming to production over the measurement period.
Data-driven supplier reviews - Scorecards gave procurement and quality a common view for discussions and CARs.
Audit-ready records - AQL plans and inspection results documented and retrievable for audits.

Lessons Learned

(1) Standardizing on Z1.4 removed guesswork and gave a defensible sampling approach. (2) Scorecards only work when they are used in real meetings with suppliers. (3) Linking incoming data to supplier master data in Power BI made scorecards maintainable. (4) Clear containment and quarantine procedures prevented rejected material from reaching the line.