How to Vet a Contract Manufacturer in China: 7 Checks

Why the first conversation matters

Most sourcing problems are visible before the first order. The warning signs are in how a supplier answers questions about process, inspection and tooling.

You do not need a factory audit to catch them. Seven questions will tell you most of what you need to know.

1. What do you run in-house?

Many trading companies present themselves as factories. Ask which machines are on site and how many of each.

Ask for a short video walk-through of the shop floor with the machines running. It takes two minutes to record and is hard to fake.

A partner who outsources is not automatically a problem. It is a problem if they do not tell you.

2. Which processes and materials are routine for you?

Every shop has a sweet spot. One is strong in aluminium CNC work, another in injection tooling, another in sheet metal.

Ask what they made last month and in what material. If your part is outside their normal range, expect a learning curve on your dime.

3. Can I see an inspection report from a recent job?

Ask for a first article inspection report or a CMM report from a job they finished recently. A generic sample from three years ago tells you little.

Look for measured values, not just pass marks. A report that only says "OK" is not a report.

4. Who owns the tooling?

For injection molds, die casting dies and custom fixtures, tooling ownership is the single most expensive thing to get wrong.

Put it in writing: the tool is your property, it is marked with your reference, and it can be moved at your request. Ask what the transfer fee would be before you need it.

5. Who actually runs the machines?

Ask how many operators, programmers and inspectors work on the floor, and whether programming is done in-house.

A supplier who cannot answer basic questions about their own process is passing your file to someone else.

6. How do you handle IP and confidentiality?

Ask whether they will sign your NDA, and whether they will keep your files off their portfolio without permission.

Also ask where files are stored and who can open them. A shared folder on every desktop is a real risk.

7. Can we start with a small paid order?

Do not begin with your full volume. Place a small order for the real part, in the real material, with the real finish.

You will learn more from one delivered batch than from ten video calls: how they pack, how they report, how they handle a problem.

Red flags worth taking seriously

• A quote that arrives in minutes with no questions about the drawing.
• No inspection report available, or one that lists no measured values.
• Reluctance to sign an NDA or to name the tooling owner.
• Prices far below every other quote, with no explanation of how.
• No clear answer about lead time or capacity.
• Pressure to pay the full amount up front.

What to send in your first message

• The 3D file and a 2D drawing with tolerances and finish.
• Material grade, not just the family.
• Quantity for the first order and the expected annual volume.
• The function of the part, in one sentence. It helps them flag risks.
• Your target date, so they can say no early if they cannot hit it.

Common questions

Should I use a trading company or a factory?

A good trading company can manage several processes and communication well. The risk is hidden subcontracting. Either way, ask who runs the machines.

How do I check quality without visiting?

Ask for inspection reports, a video walk-through, and a small trial order. Third-party inspection is worth it for the first batch of a new part.

What payment terms are normal?

Common terms are a deposit with the balance before shipment. Be cautious with requests for full payment up front on a first order.

The bottom line

Vetting is mostly asking ordinary questions and listening for specific answers. Do it once, properly, and the next ten orders get much easier.