Last updated: 2026-09-04 · 5 min read
China Mold Factory Audit — What Should You Check Before Paying the Deposit, and How Do You Verify That the Supplier Can Deliver What They Promise?
A mold factory audit evaluates 6 areas before the deposit: machining capability, steel traceability, engineering capacity, quality control, track record and communication. Four red flags disqualify a supplier: no sample CMM report, unspecified steel source, no mold flow software, refusal to provide references. Remote audit: 5–7 days, $0, covers 70–80% of risk. On-site: 2–3 days, $1,500–3,000, covers 100%.
Key Facts
<>
Process parameter — A controllable variable in the injection molding process: melt temperature, injection speed, holding pressure, cooling time, mold temperature. Each parameter affects part quality — deviations cause defects. Parameters are set during T1 and locked for production. The related guide covers adjacent topics.
What Are the Six Areas to Audit — and What Evidence Should You Request?
Six areas, each with specific evidence requirements:
| Audit Area | What to Verify | Evidence Required |
|---|---|---|
| Machining capability | CNC, EDM, wire-cut, high-speed milling, CMM | Equipment list with brand, model, age; shop floor photos |
| Steel traceability | Steel supplier (LKM, ASSAB, Bohler), mill certificates | Sample mill certificate from recent mold; steel supplier invoices |
| Engineering capacity | Mold designers, mold flow analysts, project engineers | Org chart; sample DFM report and mold flow report (redacted OK) |
| Quality control | CMM brand and calibration, inspection process | Sample CMM report from recent T1 trial; CMM calibration certificate |
| Track record | Similar molds (size, complexity, industry) | Photos of 3–5 recent molds in your industry; reference contacts |
| Communication | English capability, response time, time zone overlap | Email response time test; video call with project engineer |
The audit can be conducted remotely (video call + document review) or on-site (factory visit). For molds under $20,000, a remote audit is sufficient. For molds over $50,000, an on-site audit is recommended — it reveals the shop floor condition, operator skill level and quality culture that documents alone cannot show.
What Are the Red Flags That Disqualify a Supplier?
Four red flags:
- Cannot provide a sample CMM report. If the factory cannot show a CMM report from a recent T1 trial (even redacted), they either do not have a CMM or do not use it for T1 inspection. A CMM is a $30,000–100,000 instrument — if they do not own one, they outsource inspection (adding cost and time) or skip full-dimensional inspection (risking out-of-spec parts).
- Steel supplier is unspecified or domestic-only. If the factory cannot name the steel supplier (LKM, ASSAB, Bohler, Daido) or only uses domestic Chinese steel without mill certificates, the steel is not traceable. Non-traceable steel has a 15–30% risk of being off-spec (hardness, composition) — causing premature wear, cracking or dimensional instability.
- No mold flow analysis capability. If the factory does not have mold flow software (Moldflow, Moldex3D, Autodesk) or does not include it in the quote, the mold design is based on experience alone. This works for simple molds but fails for complex geometry (thin walls, family molds, multi-material). Mold flow analysis costs $500–2,000 per mold and prevents 80% of common molding defects.
- Refuses to provide reference contacts. If the factory cannot or will not provide contact information for 2–3 recent customers, they have no verifiable track record. A reputable factory with satisfied customers has no reason to hide references. The reference check should cover: was the mold delivered on time? Were T1 samples within spec? How were T2 modifications handled?
If any of these four red flags appears, the supplier is not suitable for your program — regardless of the price quoted. The risk of a bad supplier relationship far exceeds the savings from a lower mold price.
What Is the Remote Audit Process — and How Long Does It Take?
Six steps over 5–7 working days:
- Day 1: Document request. Send the audit checklist to the supplier. Request: equipment list, sample CMM report, sample DFM report, steel certificates, org chart, reference contacts.
- Day 2–3: Document review. Review documents against the checklist. Identify gaps (missing CMM report, unspecified steel supplier, no mold flow software). Request clarification on any gaps.
- Day 4: Video call. Conduct a 60-minute video call with the project engineer and quality manager. Walk through the shop floor (live video), ask about T1 trial process, mold modification process and change order procedure.
- Day 5: Reference check. Contact 2–3 references. Ask about delivery time, T1 sample quality, T2 modification handling and communication responsiveness.
- Day 6–7: Audit report. Compile findings into a pass/fail recommendation. If the supplier passes, proceed to contract and deposit. If the supplier fails, document the gaps and move to the next candidate.
The remote audit takes 5–7 working days and costs $0 (your time only). The on-site audit takes 2–3 days (including travel) and costs $1,500–3,000 (travel + inspector fee). For programs over $50,000, the on-site audit is the lower-risk option — it reveals issues that documents and video calls cannot (shop floor cleanliness, operator skill, quality culture).
Flash — Thin excess material that escapes between the mold parting line or around ejector pins. Cause: insufficient clamp force, worn parting line, excessive injection pressure, or contaminated mold surface. Flash thickness: 0.02–0.1mm. Requires secondary trimming to remove. The related guide covers adjacent topics.
The audit is a supplier qualification tool, not a price comparison. The goal is to confirm that the factory has the physical capability to build your mold and to identify the risks that need to be managed through the contract — before the deposit is paid.
Frequently Asked Questions
Should you hire a third-party inspection company or do the audit yourself?
For first-time buyers or programs over $80,000, a third-party inspection company (SGS, Bureau Veritas, QIMA) provides an independent assessment and standardized report. The cost is $500–1,500 per audit day.
For experienced buyers or programs under $50,000, a self-conducted remote audit is sufficient — the checklist covers the same areas a third-party inspector would check.
What is the difference between a factory audit and a mold audit?
A factory audit evaluates the mold maker’s general capability (equipment, processes, track record) — conducted before the deposit. A mold audit evaluates a specific mold that has been built (dimensional accuracy, steel verification, mold function, cosmetic condition) — conducted before the mold ships.
The factory audit is a supplier qualification tool; the mold audit is a product acceptance tool. Both are necessary for complete risk management, but they serve different purposes and are conducted at different stages.
Can you audit a Chinese mold factory without visiting China?
A remote audit covers 70–80% of the risk — it verifies documents, equipment, track record and communication. The remaining 20–30% (shop floor condition, operator skill, quality culture, material storage) can only be verified on-site.
For programs under $30,000, a remote audit is usually sufficient. For programs over $50,000, an on-site visit is recommended — the $2,000–3,000 travel cost is a small fraction of the mold cost and the risk of a bad supplier relationship.
Key Takeaways
<>
On-site: 2–3 days, $1,500–3,000, covers 100%.
If you are evaluating Chinese mold suppliers, send the supplier list and mold specification. The review covers the six audit areas, identifies red flags and recommends the supplier with the lowest program risk — not just the lowest price.
Sources: SGS — Supplier Audit Services · Bureau Veritas — Manufacturing Supplier Audit · QIMA — Factory Audit and Inspection · Plastics Technology — Sourcing Chinese Mold Makers · ThomasNet — Supplier Auditing Best Practices