How to Audit an Injection Mould Supplier’s In-House Toolmaking Capability

A credible factory audit should establish whether an injection mould supplier can design, machine, assemble, test, and inspect tools at its own facility. Look beyond capability statements: follow the production process, examine equipment and records, and compare claimed output with staffing, completed moulds, and customer work.

Start with the Production Workflow

Trace a typical project from drawing or product intake through mould design, CNC machining, assembly, trial runs, sample approval, dimensional inspection, and shipment release. Ask how engineering and production teams coordinate at each stage. Clear answers supported by visible work and records are stronger evidence of in-house capability than a list of services alone.

Verify Engineering and Machining Resources

Review design files and discuss mould structure, tooling details, and process decisions with the technical team. Longterm Mold reports having five R&D engineers specializing in moulds and precision machining. Its engineers use UG, SolidWorks, and AutoCAD for structural design, sample verification, and manufacturing-process improvements.

On the shop floor, check whether CNC machines are operating on relevant tooling work. Look for 3-axis and 5-axis systems, mould assembly in progress, inspection activity, and finished tools that can be matched to production records. Longterm Mold reports a 2,000-square-meter facility and capacity of 15–20 injection moulds per month, alongside production of tens of thousands of precision CNC-machined parts.

Check Trials, Inspection, and Quality Records

Ask to see trial documentation, mould-running results, sample parts, dimensional reports, and sample approval records. For complex precision moulds, check whether CMM measurements are available. Also review first-article inspection and pre-shipment inspection records, then confirm that the documented procedures correspond to the work actually performed.

Longterm Mold holds ISO 9001:2015 certification, certificate number 02825Q12549R0S. The stated scope covers the design, manufacture, and sale of precision moulds, as well as the sale of plastic products. Compare the certificate scope with the factory's quality documents and the specific checks used on your project.

Assess Experience for the Intended Application

Past projects can help establish whether a supplier has built tools for comparable parts and production requirements. Reported Longterm Mold examples include an electronic housing mould for an Italian manufacturer, a double shot overmoulding tool for a French product brand, a home appliance mould for a US brand distributor, and an industrial plastic part mould for an Australian manufacturer. Ask to review supporting project evidence and feedback on dimensions, surface finish, alignment, trial stability, problem solving, and delivery.

Additional Checks for Double Shot Overmoulding

For a two-material project, inspect the mould structure and ask how the supplier verifies alignment between sections. Confirm that the proposed materials, cavity arrangement, and mould steel suit the part, and review trial samples and inspection results. The listed custom double shot mould supports ABS+TPU and PP+TPE combinations, offers an optional multi-cavity design, uses 718H / 1.2738 mould steel, and has a stated service life of up to 800,000 shots. Verify these claims against drawings, tooling records, and test evidence.

Audit Evidence at a Glance

Frequently Asked Questions

Which equipment should an auditor inspect?

Check the condition and actual use of 3-axis and 5-axis CNC systems, and look for related mould assembly and inspection work. Match machines to current or completed tooling jobs instead of relying only on an equipment list.

What proves that mould trials are performed in-house?

Request trial records, mould-running results, sample parts, dimensional reports, and approval documents. These records should identify the tool and show how issues were addressed before release.

What matters most when auditing a double shot mould supplier?

Review the two-color mould structure, alignment, supported material combinations, cavity configuration, steel specification, and trial samples. Confirm each claimed capability with project-specific drawings and inspection evidence.

Conclusion

A useful audit connects the supplier's people, machines, workflow, quality records, and customer examples to the moulds it claims to build. Longterm Mold reports services spanning OEM custom plastic injection moulds, mould design and manufacture, precision machining, double shot and overmould tooling, and parts production. Its certification and reported work across electronics, appliances, and industrial applications offer evidence to examine during supplier qualification. For technical details or project support, contact rogerluo@longterm-mold.com.

About Longterm Mold

Longterm Manufacturing Solutions Limited, trading as Longterm Mold, was founded in 2010 and serves customers in the US, Europe, Australia, and other international markets. The company reports a team of 50 employees and a 2,000-square-meter factory. Its work includes mould design, tooling, precision machining, mould manufacturing, and parts production, supported by five R&D engineers using UG, SolidWorks, and AutoCAD. Longterm Mold holds ISO 9001:2015 certification and serves customers in several industries.