Last updated: 2026-09-01 · 5 min read
What Should You Check When Auditing a Mold Factory Before Placing an Order?
A factory audit before the deposit is the only way to verify that the quotation matches the capability on the shop floor. The audit is not about counting machines or taking photos for the procurement file — it is about answering one question: can this factory build the specific mold you need, at the tolerance your drawing requires, and deliver it on the schedule they quoted?
Cycle time — The total time for one injection molding cycle: injection + packing + cooling + mold open/close + ejection. Typical range: 15–60 seconds. Cycle time determines production rate and cost per part — reducing cycle by 5 seconds saves 10–15% annual production cost. See also related guide.
Key Facts
Cycle time — The total time for one injection molding cycle: injection + packing + cooling + mold open/close + ejection. Typical range: 15–60 seconds. Cycle time determines production rate and cost per part — reducing cycle by 5 seconds saves 10–15% annual production cost. The related guide covers adjacent topics.
What to Look at on the Shop Floor
The shop floor tells the truth that the sales presentation cannot. The machines, the work-in-progress, the measurement equipment, and the way operators handle the tools are the evidence that the audit exists to collect.
| Area | What to Check | Red Flag |
|---|---|---|
| CNC machines | age, axis count, maintenance log | no maintenance records, visible backlash on older machines |
| EDM | wire EDM and sinker EDM for deep ribs and corners | no EDM on site — outsourced EDM adds lead time and reduces control |
| CMM room | CMM brand, calibration sticker, temperature control | no CMM or CMM in an uncontrolled environment |
| Polish and bench | bench area cleanliness, lapping tools, surface-plate condition | no dedicated bench area — polishing done at the machine |
| Trial press | in-house injection press, tonnage range | no in-house press — trials outsourced, adds 1–2 weeks per trial |
Questions That Reveal Real Capability
If the factory cannot show you one — or if every mold in the shop is simpler than what you need — the capability gap will show up as change orders and delays during your project.
If the operator cannot do this without calling a supervisor, the CMM is underused and the dimensional reports may be unreliable.
If the answer is “we fix it and try again” without a paper trail, the factory does not have a corrective-action system.
The project engineer is the single point of contact for the entire build — if they cannot explain a DFM clearly, communication during your project will be the same.
One pattern that separates capable factories from sales-driven ones: the capable factory has a DFM review process that they initiate before you ask for it.
They will point out potential issues in your part design — draft angles, wall-thickness transitions, gate locations — during the quotation stage, not after the deposit is paid. A factory that quotes without reviewing the DFM is quoting blind and will discover the issues later, at your cost.
What to Ask Before You Leave
Before the audit ends, confirm the following in writing or by photo: the project engineer’s name and direct contact, the steel supplier for your mold base and cavity inserts, the hot-runner brand and model that will be specified, the trial-shot plan (how many shots, which press, which resin), and the dimensional report format that will be delivered at T1.
These confirmations are not negotiable items — they are the documentation that the quotation was not a generic price but a specific plan. If the factory cannot name the steel supplier or the hot-runner brand at the quotation stage, the quotation contains unspecified defaults that may change the cost and the delivery schedule when the actual components are ordered.
Frequently Asked Questions
Is a virtual audit sufficient if a physical visit is not possible?
A video call that covers the CNC area, the CMM room, the bench, and the trial press is better than no audit at all. Ask the factory to walk through a current mold build on camera and explain each step. The limitation is that video cannot reveal machine backlash, surface-plate flatness, or operator skill the way a physical visit can.
How many factories should you audit before placing an order?
Audit two or three. More than three adds procurement time without proportional information gain. The comparison between two or three factories — especially the CMM capability, the project engineer, and the DFM depth — is usually enough to identify the right fit.
Should the audit include a reference check?
Yes. Ask for two or three customer references from molds built in the last 12 months. Call or email those references and ask about dimensional accuracy at T1, communication during the build, and how the factory handled any issues that arose.
Key Takeaways
- The audit answers one question: can this factory build your specific mold at your tolerance? Counting machines or photographing the lobby does not answer it.
- The CMM operator’s skill and the corrective-action process are more predictive of T1 success than the CNC machine brand on the floor.
- A factory that reviews the DFM before quoting — and points out issues before the deposit — is a factory that has a process, not just a price.
The audit is the last opportunity before money moves to verify that the factory’s capability matches your mold’s requirements. After the deposit is paid, the only lever left is the DFM review and the T1 acceptance criteria — which is why both of those must be documented before the wire transfer, not after.
Sources
SME — manufacturing engineering resources
MMS Online — mold making resources
Plastics Technology — molding process data
Sources: Plastics Technology · Plastics Technology Online · Society of Plastics Engineers (SPE) · ThomasNet