How to Reduce Sticking in Plastic Molds with Deep Undercuts

Deep undercuts can prevent a molded part from clearing the tool during opening or ejection. To reduce sticking and avoid damage, the release approach must be designed around the part geometry. Depending on the feature, the tooling team may consider side actions, lifters, or another suitable mechanism. Longterm's supplied product information does not confirm a specific undercut-release solution, so the proposed design should be reviewed against the part drawing and validated in mold trials.

Design Review and Verification

Start by mapping each undercut to the mold-opening and ejection sequence. Ask the tooling supplier to assess whether the part can be released without interference, sticking, or deformation. A drawing or sample gives the team a basis for evaluating the geometry and recommending a suitable approach.

Longterm lists mold trial testing, dimensional inspection, and full inspection before shipment. Review trial parts for reliable release as well as dimensions and fit, and agree on acceptance criteria before authorizing production. The company also lists online technical support, mold maintenance guidance, and spare-parts supply.

Tooling Specifications to Confirm

The product listing gives a mold-base choice of S50C or P20 and cavity-steel options of 718H, 1.2738, or S136. Cold-runner and hot-runner configurations are available as options. Longterm states a precision tolerance of ±0.02 mm and a mold life of 50,000 to 1,000,000 shots. These general specifications do not establish that a particular deep-undercut feature will release reliably; confirm material and configuration choices for the specific project.

Project Review Checklist

Experience and Applications

Longterm reports completed mold projects for consumer-electronics housings and household-appliance components. These examples include mold quality and sample acceptance, but the supplied information does not state that they involve deep-undercut designs. Its ISO 9001:2015 certification covers the design and manufacture of precision molds, as well as sales of plastic products.

Frequently Asked Questions

Does the available information confirm a specific solution for deep undercuts?

No. It describes custom plastic injection tooling but does not identify a particular side action, lifter, collapsible core, or other mechanism. Submit a part drawing or sample for a feasibility review.

How can release performance be evaluated?

Include the undercut features in the mold trial, then check part release and dimensional inspection results before approving production.

What project details should be agreed before production?

Confirm the release approach, tooling materials, runner configuration, project tolerances, and sample acceptance criteria with the supplier.

Next Steps

Reliable release from a deep undercut depends on a mechanism tailored to the part and proven in trials; the published specifications alone cannot guarantee the result. Longterm lists a minimum order quantity of one set and a stated lead time of 25–40 days. For a review of a specific part feature, contact Roger Luo at rogerluo@longterm-mold.com.

About Longterm

Longterm Manufacturing Solutions Limited was founded in 2010 and provides mold design, tooling, precision machining, mold manufacturing, and parts production. The company serves customers in the United States, Europe, Australia, and other markets. It reports a 50-person team and a 2,000-square-meter factory, with recorded projects in electronics, household appliances, and industrial applications.