A factory visit answers questions a video call cannot. It is also expensive, slow, and usually happens after you have already decided you like the supplier. The useful sequence runs the other way round: qualify on documents and on a sample part first, and spend the visit confirming what you already believe.
How do you audit a stamping supplier without visiting the factory?
You audit a stamping supplier remotely with three things: a document set, a live video walkthrough, and an actual measurement of a sample part. The document set is a quality certificate such as ISO 9001:2015, a control plan and PFMEA for the part, a PPAP Level 3 submission or an equivalent first article inspection report, material certificates to the mill, a gauge calibration list, and a written list of the processes that are subcontracted out. The video walkthrough should be unscripted and should show the press line, the tool room and the inspection area. The sample part is the test that cannot be faked: ask for the dimensional report and then have the same features measured independently. Requests that stall - gauges with no calibration record, no subcontracted process list, a dimensional report with no measurement instrument named - are the answers that matter most.
The document set, in the order it is worth reading
- Quality certification. ISO 9001:2015 is the baseline. Where automotive work is involved, ask what the supplier is aligned to and treat any quality-management claim that is not backed by a certificate number as unverified.
- Control plan and PFMEA for your part. These should name the characteristics that matter and the controls applied to them, not restate the drawing.
- A PPAP Level 3 submission or an equivalent first article inspection report. Every dimension with a tolerance should be a numbered characteristic with nominal, tolerance and measured value, so the report shows the margin rather than only a pass.
- Material certificates traceable to the mill, and a statement of how material is identified on receipt and kept identified through the process.
- A gauge list with calibration dates, plus any gauge repeatability and reproducibility study for the features that decide assembly.
- A written list of subcontracted operations - heat treatment, wire EDM, passivation, electropolishing, plating, phosphating, powder coating or painting - with the sub-supplier named for each.
The video walkthrough, done properly
Ask for a live, unscripted walkthrough rather than an edited video. Walk it in a fixed order: the press line, the tool room, the inspection area, and wherever the finished parts are packed. What you are looking for is not polish. It is whether the tool room exists at all, whether the inspection area has instruments on the bench or in a cupboard, and whether the person holding the phone can answer a question about a part they did not expect to be asked about. A supplier who owns its tooling is a different supplier from one who sends dies out, and the difference does not show up in a quotation.
The sample part is the part that cannot be faked
Ask for the dimensional report for a sample, then have two or three of the functional features measured independently on the part you hold. Compare the numbers. A report without a named instrument, a report where every value sits exactly at nominal, or a report that covers height and diameter but not the wall thickness and its measurement point - all of those tell you more about the system than any certificate does.
Answers that should stop the process
- No list of subcontracted processes, or a claim that everything is done in house when the equipment list does not support it.
- A dimensional report with no measuring instrument named, or with values that only ever read as nominal.
- No calibration records for the gauges used on your features.
- A quality claim with no certificate number behind it.
- A tool room that is described but cannot be shown on a live call.
Key point
Qualify remotely on documents, a live walkthrough and an independently measured sample part. Then visit to confirm, not to discover. The three answers that decide it are whether the tooling is in house, whether the gauges are calibrated, and whether the subcontracted processes are declared.
Frequently asked questions
What documents should I ask a stamping supplier for?
A quality certificate such as ISO 9001:2015, a control plan and PFMEA for the part, a PPAP Level 3 submission or equivalent first article inspection report, material certificates traceable to the mill, a gauge calibration list, and a written list of subcontracted processes with the sub-supplier named.
Can a factory audit be replaced by a video walkthrough?
A live, unscripted walkthrough covers a lot of the ground a first visit would: whether the tool room is in house, whether the inspection area is in use, and how the team answers an unexpected question. It does not replace the sample part measurement, which is the part of the audit that is hardest to present well without being real.
What is the single strongest signal in a supplier audit?
Whether the tooling is owned and maintained in house, with the tool room shown live on a call and the die list available. It decides the lead time for a change, the response when a tryout does not hold, and whether a design change becomes a two-week or a two-month conversation.
Why does the subcontracted process list matter so much?
Because it is the difference between a supplier who can describe the whole route of your part and one who can only describe the part of it they do. Heat treatment, wire EDM, passivation, electropolishing, plating, phosphating and coating are commonly subcontracted, and each adds its own lead time, documentation and compliance obligation.