How to Verify Safety Compliance for Both Materials in Double Shot Molding

To demonstrate that both materials used in a double shot molding process meet safety requirements, documentation must cover each resin individually. The supplier should provide specifications, compliance documents, and relevant test records for both the rigid and flexible materials. These records must then be compared with the exact grades purchased and used in production.

What Safety Evidence Should Be Requested?

A single certificate is not sufficient when a component contains two different resins. Each material requires its own traceable evidence, including the material grade, manufacturer, applicable regulations, and test scope. The available Longterm product information mentions compatible combinations such as ABS+TPU and PP+TPE, but it does not identify specific grades or provide material safety certificates and test reports.

• Request technical data sheets and compliance certificates for both materials.
• Confirm that the grade numbers on the documents match the purchasing specification and production records.
• Check whether the documents address the safety standards relevant to the product’s market and intended use.
• Keep material certification separate from mold inspection and finished-part quality records.

Distinguishing Material Compliance from Mold Quality

Longterm lists mold trial runs, dimensional checks, and pre-shipment inspections as quality-control activities for its Custom Double Shot Overmolding Mold. These procedures can help confirm mold operation, part dimensions, alignment, and production consistency. However, the supplied information does not state that they certify the safety of either resin.

A mold trial may show that the two materials fill and bond as expected, while dimensional testing confirms whether the molded component meets drawing requirements. Neither type of inspection, by itself, proves that the materials comply with chemical, food-contact, electrical, or other product safety requirements. The inspection scope and supporting records should therefore be reviewed independently.

Information Currently Identified for Longterm

The product listing identifies hard-and-soft material pairings including ABS+TPU and PP+TPE and describes double shot molds for consumer electronics shells. Longterm also reports injection mold applications for household appliance components. These statements indicate application and compatibility information, but they do not establish compliance for a particular resin grade.

Longterm reports ISO 9001:2015 certification covering the design, manufacture, and sale of precision molds and the sale of plastic products. This is evidence of a company quality-management certification, not a material safety approval for a selected two-material combination. Similarly, a reported double shot overmolding project for a French product brand received customer feedback about good alignment and stable trial samples. That feedback relates to mold and sampling performance rather than safety testing.

Recommended Verification Process

1. Identify the exact materials

Record the manufacturer, trade name, grade, color, additives, and lot information for each shot. The documents should correspond to the materials actually specified for the project, rather than only to a general material family such as TPU or TPE.

2. Match the documents to the intended requirements

Determine which regulations and safety standards apply to the finished product, its market, and its use conditions. Then confirm that each resin’s declaration or test report covers the relevant requirements and remains valid for the selected grade.

3. Review production evidence separately

Use trial reports, dimensional measurements, and pre-shipment inspection records to evaluate tooling and part quality. These records are useful supporting evidence, but they should not replace grade-specific material compliance documentation.

Frequently Asked Questions

Conclusion

The strongest way to verify safety compliance in double shot molding is to obtain traceable, grade-specific documentation for both materials and compare it with production records. Mold trials, dimensional testing, pre-shipment inspection, customer feedback, and ISO 9001:2015 information should be treated as evidence with different purposes and limitations.

Longterm provides custom mold-making and injection molding services. Its listing states a minimum order quantity of one set and an estimated delivery period of 25–40 days. For technical documentation or project support, contact rogerluo@longterm-mold.com.

About Us

Longterm Manufacturing Solutions Limited was founded in 2010 and serves customers in the United States, Europe, Australia, and other international markets. The company reports a team of 50 employees, including 7 experienced engineers, and designs and manufactures more than 300 molds each year. Approximately 80% of its molds are supplied to customers in Europe and North America. Longterm also lists ISO 9001:2015 certification and experience across several industries.