Custom Baby Stroller Safety Harness Buckle Injection Mold

DeepMould developed this baby stroller buckle injection mold for a multi-component buckle used in a baby stroller harness assembly.

The POM assembly consists of an outer buckle housing, a central release ring and side locking tongues. The project covers prototype support, mold design, mold manufacturing, trial molding and volume injection molding.

The tooling and molded components are produced according to the customer's approved product data and requirements.

Product & Tooling Considerations

A harness buckle is an assembly rather than a single plastic part. The individual components need to work together according to the approved product design.

The side locking tongues must enter the buckle body correctly, remain aligned after assembly and release through the central component as specified by the customer's design.

For the injection mold, this requires attention to the interfaces between components, wall thickness, ribs, openings, shut-off areas and ejection positions.

The visible buckle surfaces also require consistent appearance. Texture, logo definition, parting-line position and gate location should therefore be reviewed together with the internal functional geometry.

Mold Development Process

Before steel machining, the product data is reviewed for draft angles, undercuts, shut-off conditions, sub-gate access, ejection and the relationship between assembled components.

The proposed tooling uses S136 steel with the specified hardness range and incorporates four sliders per cavity. The cavity configurations are 1 × 4 and 1 × 8 for the corresponding buckle components.

After machining and mold assembly, trial molding is performed to evaluate molding conditions, visible defects and dimensional conformity against the approved product requirements.

Any subsequent product or tooling changes are controlled according to the applicable drawing revision.

Trial Molding & Assembly Verification

The molded components are checked against the approved drawings and project requirements during the trial stage.

The customer performs final assembly-force testing according to its own test method and acceptance limits, including insertion, retention and release-force requirements where applicable.

This allows the molded components and tooling to be evaluated against the customer's defined product requirements before volume production.