Step 1: Check the business licence and scope
Ask for the 18-digit Unified Social Credit Code and confirm the registered scope includes plastic product manufacturing. A trading company can be a valid partner, but the price and lead time you are quoted should be traceable to a specific production site.
Step 2: Confirm the factory, not just the office
Request a live video walkthrough showing the moulding floor, mould store, material warehouse and QC area. Look for machine tonnage plates, mould identification tags and material lot labels. A factory that cannot show these on camera is usually outsourcing.
Step 3: Verify tooling capability
Ask who designs and builds the mould. In-house tooling means faster engineering changes and clearer responsibility when parts fail. If tooling is outsourced, get the mould maker name and their steel specification (P20, 718H, S136 and so on).
Step 4: Review quality documentation
- ISO 9001 certificate with a valid scope and expiry date
- Material datasheets with lot numbers matching your samples
- Dimensional reports (CMM or first-article inspection) for the sample you received
- Food contact test reports if the part touches food
Step 5: Test communication under pressure
Send a technical question with a specific tolerance or resin grade and see how long a substantive answer takes. Suppliers who respond with engineering detail rather than sales copy are usually the ones who will handle a production issue properly.
Step 6: Start with a small trial order
A trial order of one carton verifies packing, labelling, lead time and shipping documentation before you commit to a container. Keep the trial PPAP or first-article report on file as the baseline for future lots.
Where to start
Our verified company directory lists Chinese plastic manufacturers with their category focus, and the custom moulding services section shows factories that offer OEM tooling programmes.
