Insert Molding

Overview

Insert molding is a specialized manufacturing process where pre-formed metal inserts or components are placed into a mold cavity before plastic injection. The molten plastic flows around the insert, creating a permanent mechanical and chemical bond in a single operation.

Our insert molding capabilities handle brass, steel, aluminum, and stainless steel inserts combined with engineering thermoplastics. Applications include threaded inserts, electrical connectors, medical devices, and automotive components with embedded metal features.

Insert Molding Capabilities

Parameter	Capability	Application
Insert Materials	Brass, Steel, SS, Aluminum	Various applications
Insert Size Range	M1 – M20 threads	Small to large fasteners
Plastic Materials	PA, PBT, PC, ABS, PPS	Engineering applications
Pull-out Strength	Exceeds insert yield strength	Permanent bonding
Automation	Robotic insert loading	High-volume production

🔧 Insert Molding Process

Step 1: Insert Preparation

Metal inserts are cleaned, preheated (if required), and positioned in the mold. Preheating removes moisture and improves plastic flow around the insert. Our automated systems ensure precise insert placement (±0.01mm).

Step 2: Mold Closing

The mold closes with the insert securely held in place by magnets, pins, or custom fixtures. Proper insert retention prevents movement during injection.

Step 3: Plastic Injection

Molten plastic is injected around the insert at controlled pressure and temperature. The plastic flows into knurled features, holes, or undercuts on the insert surface.

Step 4: Cooling & Bonding

As the plastic cools, it shrinks around the insert, creating mechanical interlocking. Chemical bonding also occurs at the molecular level for compatible material combinations.

Step 5: Part Ejection

The completed insert-molded part is ejected as a single integrated component. No secondary assembly operations are required.

📦 Insert Types

Threaded Inserts

• Brass Threaded Inserts: Excellent corrosion resistance, good machinability
• Stainless Steel Inserts: High strength, chemical resistance
• Steel Inserts (Plated): Cost-effective, zinc or nickel plating

Electrical Components

• Connector Pins: Copper alloy pins for electrical connectors
• Busbars: Embedded conductive paths
• Terminals: Pre-wired terminals for wire harnesses

Structural Inserts

• Metal Bushings: Wear-resistant bearing surfaces
• Reinforcement Plates: Metal strengthening in high-stress areas
• Magnets: Rare-earth magnets embedded in housings

🎯 Industry Applications

Industry	Typical Parts	Insert Types
📱 Electronics	Connectors, housings, switches	Pins, terminals, bushings
🚗 Automotive	Sensors, connectors, assemblies	Threaded inserts, bushings
🏥 Medical	Surgical tools, device housings	SS inserts, metal blades
🔧 Industrial	Valves, fittings, tool handles	Threaded inserts, bushings

🔍 Quality Control

• Pull-out Testing: Verify insert retention strength exceeds specifications
• Torque Testing: Threaded inserts tested for installation and removal torque
• Visual Inspection: Check for flash, voids, incomplete encapsulation
• Dimensional Inspection: CMM measurement for critical features
• X-ray Inspection: Internal void detection for critical applications
• Electrical Testing: Continuity and insulation resistance for connectors