An overseas CNC machine shop audit should answer one question: can this supplier repeatedly manufacture the released drawing and prove that each shipment meets the agreed requirements? Certificates and polished presentations are useful context, but evidence from a real work order is stronger.
12-point CNC supplier audit checklist
| Control | Evidence to request | Main risk |
|---|---|---|
| Legal identity | License, quotation, contract and bank beneficiary | Undisclosed commercial party |
| Factory control | Live production walk and machine records | Hidden outsourcing |
| Drawing control | Released revision and traveler | Wrong revision |
| Material | Lot identity and certificate trail | Wrong alloy or condition |
| Inspection | Method, calibration and report | Unmeasurable tolerance |
| Capacity | Loaded hours and bottleneck plan | Unreliable lead time |
1. Confirm the legal manufacturing entity
Match the registered company name across the business license, quotation, contract, invoice, bank account and shipping paperwork. A trading company is not automatically unacceptable, but its role and the actual production site must be disclosed.
2. Verify control of machines and production
Request a live, unscripted walkthrough from incoming material through machining, inspection and packing. Ask operators about the part family being produced. Compare machine nameplates and workshop capacity with the equipment list supplied during quotation.
3. Trace one real work order
Select a completed production lot and follow its part number, drawing revision, program, setup sheet, material lot, in-process checks, final report and packing label. A connected record trail is more meaningful than isolated sample documents.
4. Test drawing and revision control
Ask who releases drawings, how obsolete files are blocked, how translated notes are controlled and how engineering changes reach programming, production and inspection. Confirm which file controls when the model and drawing conflict.
5. Verify material authenticity and traceability
Trace the heat or lot number from the material certificate to stock identification, job traveler and finished-part record. Confirm how remnants are labeled and segregated. For critical applications, define whether independent material testing is required.
6. Challenge measurement capability
Choose a characteristic that matters to assembly and ask which instrument, fixture and method will measure it. Review resolution, calibration status, operator instruction, sampling frequency and report format. A CMM does not solve an unsuitable datum strategy or fixture.
7. Review first-article and production approval
Confirm when first-article inspection is required, how many pieces are measured and who approves release. Production-intent material, tooling, finishing and inspection methods should be used when the sample is expected to represent future lots.
8. Examine nonconformance and corrective action
Review a closed nonconformance record. It should show containment, affected quantity, root cause, corrective action, effectiveness verification and disposition approval. Ask how the supplier prevents rejected parts from returning to production.
9. Audit special-process and subcontractor control
Identify anodizing, heat treatment, plating, grinding or testing performed outside the facility. Confirm approved suppliers, incoming verification, certificate review, lot traceability and responsibility when a subcontracted process fails.
10. Test capacity and lead-time assumptions
Break the quoted lead time into material, programming, setup, machining, special process, inspection, packing and freight. Compare required spindle hours with current load. Ask for contingency plans for the true bottleneck, not only total machine count.
11. Review packaging and shipment release
Inspect edge protection, cleanliness, corrosion prevention, part separation, labels and document matching. Shipment release should reference the correct purchase order, part number, revision, quantity and inspection status.
12. Finish with a controlled pilot order
Choose a pilot that exposes the important risks rather than the easiest geometry. Freeze the revision, material, critical characteristics, inspection method, sample size, packaging and corrective-action timing before production begins.
Remote audit evidence package
- Legal registration and matching payment beneficiary
- Live workshop route from material to shipment
- Machine list and current capacity plan
- Sample traveler, inspection report and calibration record
- Material certificate linked to a real lot
- Closed nonconformance and corrective-action example
- Subcontractor-control and packaging records
Frequently asked questions
Can a remote audit replace an on-site audit?
It can screen suppliers and verify many controls. High-risk, regulated or safety-critical programs may still require an independent or on-site audit.
Should buyers reject every trading company?
No. The risk is undisclosed outsourcing or weak process control. A transparent integrator may be useful when responsibilities and evidence are clear.
What is the best final test?
A paid pilot order with drawing-specific acceptance, traceability and reporting requirements.
Request a drawing-based manufacturing review
Send the controlled CAD package, quantity, material, finish and critical characteristics. WEKO can review manufacturability and production evidence before quotation.
