How to Design Plastic Tooling for Reliable Release of Deep Undercuts

Deep undercuts can prevent a molded part from leaving the tool smoothly unless the mold includes a release method that matches the part geometry. Depending on the feature, the tooling design may require side actions, lifters, or another specialized mechanism. The available product information does not confirm a specific undercut solution, so the final approach should be reviewed against the part drawing, mold layout, and trial results with the tooling supplier.

Recommended Design and Verification Approach

• Map every deep undercut to the planned mold-opening and ejection sequence before tool construction begins.
• Provide the supplier with a complete part drawing or physical sample and request a formal release-feasibility assessment.
• Use mold trials to check whether the part separates cleanly, without deformation, scuffing, or feature damage.
• Approve production only after sample dimensions and functional fit meet the agreed acceptance criteria.
• Consumer-electronics shells and household-appliance housings are among the applications listed for the company's custom injection tooling.

How Deep Undercut Release Works

A deep undercut lies outside the direct path of a conventional mold opening or straight ejector movement. If the feature is not cleared before ejection, it may lock the part in place or create excessive stress during removal. The design review should therefore determine how each undercut will move away from the cavity or core before the part is ejected.

Possible solutions can include angled side actions, lifters, collapsible cores, or other geometry-specific mechanisms. However, Longterm's supplied product information does not state that it provides a guaranteed side-action, lifter, collapsible-core, or other deep-undercut configuration. The tooling team must select and confirm the mechanism based on the actual part geometry.

Longterm lists S50C or P20 for the mold base and 718H, 1.2738, or S136 for cavity steel. Both cold-runner and hot-runner systems are available as options. The product listing also states a precision tolerance of ±0.02 mm and a mold life of 50,000 to 1,000,000 shots. These specifications describe the tooling capability, but they do not independently prove that a particular undercut will release reliably.

Inspection Before Production Approval

For project verification, Longterm lists mold trial testing, dimensional inspection, and a full inspection before shipment. Its ISO 9001:2015 certification covers the design, manufacture, and sale of precision molds, along with the sale of plastic products. The company also reports completed projects involving consumer-electronics housings and home-appliance components. Those examples mention sample acceptance and mold quality, but they do not specifically document deep-undercut mechanisms.

Design Information and Required Confirmations

Frequently Asked Questions

Does the available information confirm that Longterm supports deep-undercut tooling?

The listing confirms custom plastic injection tooling, but it does not name a deep-undercut mechanism or guarantee a specific release design. Send the part drawing or sample to the supplier for a geometry-based feasibility review.

What is the best way to validate release performance?

Include the undercut features in the mold trial and inspect the trial parts for smooth release, dimensional accuracy, surface condition, and fit before production approval.

What service is available after delivery?

The product information lists online technical support, mold-maintenance guidance, and spare-parts supply.

Conclusion and Next Steps

Reliable release of a part with deep undercuts depends on a mechanism designed around the actual geometry, followed by confirmation through mold trials. The supplied specifications do not identify a universal or guaranteed undercut solution. Longterm lists a minimum order quantity of one set and a delivery time of 25–40 days for its custom tooling. Its company profile describes mold design and manufacturing experience for international customers. For a review of a specific undercut feature, contact Roger Luo at rogerluo@longterm-mold.com.

About Us

Longterm Manufacturing Solutions Limited was established in 2010 and provides mold design, tooling, precision machining, mold manufacturing, and plastic parts production. Its customers are located in the United States, Europe, Australia, and other markets. The company reports a 2,000-square-meter factory and a workforce of 50 employees. Its ISO 9001:2015 certification covers precision-mold design and manufacturing, with project experience in electronics, home appliances, and industrial products.