Insert Molding

Typical applications

• Threaded metal inserts for repeated fastening in plastic housings
• Electrical terminals and contacts molded directly into connector bodies
• Bearing races or shafts molded into plastic mechanisms
• Multi-material structural components requiring a metal load path

Process overview

1. 1

   Insert qualification

   We confirm the insert's dimensions, material, and how it will be held and located in the cavity before tooling design finalizes.

2. 2

   Tool design for insert loading

   Molds are designed with insert-specific locating features, whether inserts are loaded manually or via automation.

3. 3

   Molding

   Plastic is injected around the pre-placed insert in a single cycle.

4. 4

   Pull test / retention verification

   Insert retention is verified against your requirement (pull-out force, torque-out, or equivalent).

Part design considerations

• Adequate plastic encapsulation around the insert to resist pull-out and torque-out
• Insert placement tolerance and how it affects wall thickness around the insert
• Material compatibility and thermal expansion mismatch between insert and resin
• Whether inserts are loaded manually, semi-automated, or fully automated based on volume

DFM guidance

• Specify required retention force (pull-out and torque-out) up front so we can validate boss geometry around the insert
• Avoid insert features with sharp edges that can create stress risers in the surrounding plastic
• Tell us your annual volume early — it determines whether manual insert loading is practical or automated loading should be tooled in

Quality controls

• Insert retention testing (pull-out / torque-out) documented per your specification
• Visual and dimensional inspection of plastic encapsulation
• Incoming inspection of supplied inserts when customer-furnished

Secondary operations available

• CNC machining of molded features
• Assembly into higher-level components
• Pad printing and decoration

Frequently asked questions