Factory audit checklist: how to judge a supplier on site

What kind of audit do you need?

“Factory audit” covers three different jobs, and mixing them up is a common reason audits disappoint.

For a new supplier, the capability audit comes first. There is no point verifying working hours at a factory that cannot hold your tolerance. This guide focuses on the capability and quality system audit, with the social basics every buyer should check.

Before the visit

Send the factory your drawing and ask for a short pre-audit pack: company registration, list of main machines with capacity, organisation chart, quality certificates, a sample inspection report and a sample calibration record. The supplier health check gives you a scored desk review from the same information.

Plan to spend most of the day on the shop floor where your part would be made. The meeting room tells you what the factory wants you to see.

The checklist: eight areas

Score each area from 0 to 4 on what you saw, not what you were told. A simple scale: 0 = absent, 1 = informal, 2 = exists but inconsistent, 3 = working with records, 4 = working, recorded and improved.

1. Legal and commercial basics

• Registered entity, GST and export registration match the entity that will invoice you.
• Ownership, years in business, main customers and export markets.
• Which processes are in-house and which are subcontracted, and to whom.

2. Capacity and planning

• Machines that would run your part: size, age, condition and current load.
• How orders are planned and how delivery dates are set and tracked.
• Realistic monthly capacity for your part, including the other customers on those machines.

3. Equipment and maintenance

• Preventive maintenance plan and records for key machines.
• Tooling storage, tool identification and tool life records.
• Spare parts for critical equipment.

4. Measurement and calibration

• Gauges suited to your tolerances: a vernier cannot verify ±0.02 mm.
• Calibration status labels and a calibration register traceable to a recognised standard. ISO 9001:2015 covers this in clause 7.1.5.
• Who is trained to measure, and whether results are recorded or just “checked OK”.

5. Incoming material control

• Supplier list for raw material and bought-in parts.
• Mill test certificates checked against the specified grade, with spot tests where it matters.
• Identification and segregation of material on receipt.

6. Process control

• Work instructions at the machine, in the language operators read.
• First-off approval after every setup, and in-process checks at a set frequency.
• Process capability data on critical dimensions. A Cpk of 1.33 or more is a common target; the Cpk calculator shows what that means for your tolerance.

7. Final inspection and traceability

• Final inspection to a written plan, with records.
• Batch or heat identification from raw material to finished carton (ISO 9001:2015 clause 8.5.2).
• Packing to specification and correct shipping marks.

8. Nonconformity and corrective action

• Rejected parts are identified, segregated and recorded (clause 8.7).
• Customer complaints are analysed and closed with a corrective action (clause 10.2).
• Evidence that a past problem was actually fixed, not just reported.

Social, health and safety basics

Even in a capability audit, record what you see: emergency exits clear and marked, fire equipment in date, machine guarding, PPE in use, drinking water and toilets, and no signs of underage workers. Serious concerns here call for a full social audit before you place orders.

Worked example: scoring two die-casters

Note how the lower total and the critical finding tell the same story. A single critical finding, on something that decides whether your part is good, should block approval regardless of the total.

Video audits: useful, with limits

When travel is not practical, a live video audit is a reasonable first screen. It works best when you direct the camera, not the factory.

• Send a shot list in advance: the machines for your part, the gauge room, the calibration register, the raw material store, the final inspection area and the packing line.
• Ask for close-ups of calibration labels, machine nameplates and a recent inspection record, with today’s date visible.
• Walk the route without cuts. A continuous walk from the gate to the packing area is harder to stage than a series of clips.
• Ask an operator to measure a part on camera with the gauge they would use.

A video audit can confirm that equipment and records exist. It is weaker at judging housekeeping, discipline and how people actually work, and it cannot check what is off camera. Use it to shortlist, then audit the finalists on site before volume orders, especially for safety-critical or tight-tolerance parts.

After the audit

Write the report the same week, with photos, scores, findings graded critical, major or minor, and agreed corrective actions with dates. Follow up on every corrective action with evidence, not a promise.

Then move to samples. An audit tells you the factory can make your part; a first-article inspection and a signed golden sample prove that it did. Keep audited suppliers on a re-audit cycle, commonly every 12 to 24 months, and use pre-shipment inspections to check each lot in between.

Mistakes to avoid

• Auditing the showroom. Ask to see your part’s machines and records.
• Accepting a certificate as proof. Verify it, then audit anyway.
• Scoring on conversation. “We always check” scores 1 until you see the record.
• Ignoring subcontractors. If plating or heat treatment is outsourced, ask who does it and how it is controlled.
• Letting findings drift. An open corrective action after 90 days is a finding in itself.