What buyers should verify first
A reliable decision starts with evidence that matches the drawing, production volume and business risk. Use the table below during RFQ review; replace assumptions with named documents, owners and acceptance criteria.
| Review area | What good control looks like | Buyer action |
|---|---|---|
| Containment | Stop shipment/use and identify all affected lots | Immediate |
| Validation | Confirm drawing, datum and measurement method | Before disposition |
| Disposition | Use-as-is, rework, repair or scrap by authorized decision | Documented |
| Corrective action | Address occurrence and escape causes | Evidence based |
| Effectiveness | Verify later lots remain controlled | Time bound |
1. Define the population
Record PO, part number, revision, lot, quantities at supplier/in transit/at buyer and serial or date codes where relevant.
For sourcing approval, convert this point into a written requirement: identify the responsible party, evidence to retain, acceptance rule and response when the rule is not met. This keeps a sample success from being mistaken for a capable production system.
2. Align measurement methods
Share setup photos, datum simulation, instrument resolution and raw readings. Arrange third-party measurement when disagreement persists.
For sourcing approval, convert this point into a written requirement: identify the responsible party, evidence to retain, acceptance rule and response when the rule is not met. This keeps a sample success from being mistaken for a capable production system.
3. Protect assembly with a verified sort
A sort instruction needs a clear characteristic, method, acceptance limit, marking and record.
For sourcing approval, convert this point into a written requirement: identify the responsible party, evidence to retain, acceptance rule and response when the rule is not met. This keeps a sample success from being mistaken for a capable production system.
4. Separate occurrence from escape
Why was the defect made, and why did the control plan fail to detect it? Corrective action must address both.
For sourcing approval, convert this point into a written requirement: identify the responsible party, evidence to retain, acceptance rule and response when the rule is not met. This keeps a sample success from being mistaken for a capable production system.
5. Close with effectiveness evidence
Review subsequent lots, capability data or layered audits. A revised work instruction alone does not prove improvement.
For sourcing approval, convert this point into a written requirement: identify the responsible party, evidence to retain, acceptance rule and response when the rule is not met. This keeps a sample success from being mistaken for a capable production system.
Practical buyer scenario
If a bore is reported undersize, first confirm temperature, gauge, datum and coating condition. Then trace tool wear and sampling records before deciding rework or replacement.
The useful output is a controlled plan, not a promise. Record the drawing revision, assumptions, open questions, required evidence and approval gate in the RFQ or purchase order. For critical applications, obtain engineering, quality and regulatory review appropriate to the product.
RFQ checklist
- Controlled 3D model and 2D drawing with matching revision
- Material grade, condition or temper, and any certificate requirement
- Quantity per release, annual demand and target delivery date
- Critical-to-quality characteristics and agreed measurement method
- Surface finish, cosmetic zones, masking and post-finish dimensions
- Packaging, labeling, Incoterm and destination
- First-article, sampling, traceability and corrective-action expectations
Frequently asked questions
Who decides use-as-is?
The authorized design/customer organization, not the supplier alone.
Should I return all suspect parts?
Not before lot identification and evidence preservation; agree on logistics and disposition.
What is an 8D?
A structured team method for containment, root cause, corrective action and recurrence prevention.
When is third-party inspection useful?
When measurement disagreement, high risk or urgent containment justifies independent evidence.
Sources and further reading
Technical note: Examples in this guide are planning guidance, not a universal manufacturing specification. Final capability, certification, tolerances, treatment and acceptance criteria must be confirmed for the exact drawing and contract.
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