How to evaluate a supplier.

A sample tells you what a factory can produce once, with care, under scrutiny. It does not tell you what a second order looks like in six months, or what happens when a plating bath drifts, or who is accountable when a lot fails inspection.

These ten questions do.

1. Which production steps are in-house?

"Everything" is not a credible answer at most factory sizes. Polishing, plating, casting and assembly are commonly split across specialist workshops in the same district.

What you are testing is whether the supplier knows their own chain and can name it. A manufacturer will say "we cast and polish here, plating goes to a partner two streets away who has done our work for nine years". A middleman will say "we handle all processes". The second answer is not a lie exactly — it is just an answer that tells you nothing about accountability.

2. What grade of steel, and can I see the mill certificate?

304 and 316L are the two answers, and a real supplier will make both. If the response is "high quality stainless steel" without a grade, the answer is that they buy on price and do not know what arrives.

A mill certificate (material test report) for the heat or lot is a normal document, and it is the one piece of paper a factory should be able to produce from its own file. A supplier who cannot produce one is buying from the spot market without traceability.

Be careful with the next question, because it separates two different things. A mill certificate proves what the steel is; it says nothing about what comes off the finished piece. Nickel release, lead and cadmium, and REACH testing are done by accredited laboratories on the finished article, and the better factories will tell you plainly that they do not hold those reports as standing certificates — they commission them per order, or let your own lab handle it. A supplier who claims to be "REACH certified" as a factory is usually describing one test report on one batch.

3. What plating process, and at what thickness?

This is the single most revealing question. PVD and electroplating are different processes with different durability. Ask for the thickness in microns.

• A supplier quoting PVD at 0.5–1 µm is giving a real specification.
• A supplier quoting "advanced plating technology" without a number is selling appearance.

Electroplated gold on stainless steel at 0.03 µm will lose colour at the high points within months. PVD at 1 µm will not. Same visual appearance on day one.

4. Who owns the tooling?

Agree this in writing before development starts. The correct position: tooling paid for by the client belongs to the client, and is not used for other buyers.

A supplier who will not commit to that in writing is telling you something about how they intend to use your design.

5. What is the inspection standard, and at how many stages?

"Inspected before shipping" is the standard non-answer. You want: an AQL level, the definition of major and minor defects, and the number of inspection points.

Four points is right for jewelry: after forming, after polishing, after plating, at packing. If a supplier inspects only at the end, the defects were already paid for.

6. Can I see a pre-shipment inspection report from a past order?

Ask for a real one, redacted. A supplier who runs inspections has documents. A supplier who does not has an excuse that sounds reasonable.

7. What happens if a lot fails inspection?

The answer should describe a process, not a promise. Rework, replacement, or rejection against the agreed specification — and who pays for it. If the answer is "it won't happen", that is an answer from someone who has not been through it.

8. Can you give me two references in my market?

Specifically in your market, because compliance requirements and buyer expectations differ between the US, the EU and elsewhere. A reference in a different market may be genuine and still irrelevant.

A supplier who cannot give references at all, after years in business, has a reason.

9. What is the process for a reorder — will the colour match?

This question is designed to expose the difference between a factory that retains reference samples and one that does not. PVD colour drifts between batches. A proper answer describes a retained approved sample and matching production against it.

10. Which parts of my design do you advise changing, and why?

This is the most valuable question and the one buyers ask least. A manufacturer with real material knowledge will push back — on a wall thickness that will distort, a clasp that will fail at that weight, an engrave that will not read at that size.

A supplier who agrees with everything you propose is a supplier who will build the problem you described and then charge you to fix it.

Reading the pattern

Rejection is the strongest signal. Any single supplier can be good at samples and weak at reorders. The pattern to look for is a supplier who tells you what will not work — before you have paid for it.