When sourcing injection molds from China, verification is critical. A good factory visit can save you thousands of dollars in rework and delays. Here is our practical audit checklist based on years of buyer feedback.
Before Visiting: Document Check
- Business license (营业执照) — confirm the registered name matches the factory sign
- Export license — most mold makers have this; essential if shipping abroad
- ISO 9001 certification — verify the certificate number online
- Client portfolio — ask for 3-5 reference clients you can contact
- Factory photos and videos from the last 6 months, not stock photos
Red Flag: Company address is in a commercial building, not an industrial zone. Many "mold companies" are actually trading companies with no production capacity of their own.
On-Site Inspection: What to Check
1. Machine Shop
- CNC machines: How many? What brands? (Mitsubishi, Fanuc, or local brands)
- EDM / Wire-cutting: Check if they have in-house capability or outsource
- Machine maintenance: Look at the environment—clean machines = more disciplined operation
- Age of equipment: Machines older than 10 years may affect precision
2. Mold Assembly Area
- Bench layout: Organized benches with proper lighting indicate professional assembly
- Fitting tools: Quality fitting tools (micrometers, granite surface plates) show investment in quality
- Assembly tolerances: Ask what their standard fit tolerance is (0.01mm or 0.02mm?)
3. Quality Control
- CMM (Coordinate Measuring Machine): Do they have one? Is it calibrated?
- Hardness tester: Rockwell or Brinell on-site? Check calibration date
- Inspection reports: Ask to see sample CMM reports from recent projects
- Material certificates: Can they provide mill certificates for mold steel?
4. Trial Room
- Injection molding machine on-site: Minimum 80-150 ton for standard trials
- Data collection: Do they record molding parameters for each trial?
- Cooling system: Proper cooling line setup indicates good process control
Good Sign: A factory that actively documents their mold trials with photos, parameters, and defect analysis is likely to deliver consistent quality.
Key Questions to Ask
1. "What is your main market?" — Factories exporting to EU/Japan/US typically have higher standards.
2. "What is your mold warranty?" — Standard is 1 year or 1 million cycles, whichever comes first.
3. "What DFM (Design for Manufacturing) report do you provide?" — Professional molders always provide DFM before cutting steel.
4. "How do you handle mold changes after T1?" — Get the policy in writing: what's included, what's extra.
5. "Can you show us your mold maintenance records?" — Shows long-term quality commitment.
Common Red Flags
- Price 50%+ below market average — usually means shortcuts (cheaper steel, fewer cooling channels)
- Pushing for 50%+ deposit upfront — standard is 30% with balance on shipment
- No English-speaking staff — communication will be a constant struggle
- No DMU files or mold flow analysis offered — suggests limited engineering capability