For Plastic and Metal Integrated Parts
Sunpeakmold provides professional insert molding services that combine plastic injection molding with metal inserts — creating strong, durable, and functional components in a single integrated process. From brass nuts and threaded inserts to stamped metal parts and terminals, we ensure precise positioning and reliable bonding.
A Precision Process That Integrates Metal and Plastic in One Shot
Insert molding is an injection molding process where metal inserts (such as threaded nuts, bushings, pins, terminals, or stamped parts) are pre-placed into the mold cavity before the molten plastic is injected. The plastic encapsulates and bonds with the insert, creating a single integrated component.
Insert Preparation
Insert Placed in Mold
Plastic Injection
Instead of Secondary Assembly?
Insert molding outperforms traditional post-assembly methods by delivering stronger parts, fewer production steps, and higher consistency.
Stronger Part Structure
Plastic encapsulates the insert under high pressure, creating a mechanical bond far stronger than press-fit or adhesive assembly.
Reduced Assembly Steps
Eliminates post-molding insertion, pressing, or welding operations — consolidating multiple processes into one.
Improved Position Accuracy
Inserts are fixed in the mold cavity before injection, ensuring consistent positional tolerance of +/-0.05mm.
Better Thread Performance
Threaded inserts are permanently embedded — no thread stripping or loosening over repeated assembly cycles.
Stable Functional Connection
Provides reliable electrical conductivity for terminals and connectors, and mechanical stability for structural inserts.
Efficient Mass Production
Single-step molding dramatically reduces cycle time and per-part cost in high-volume production runs.
Insert Types We Can Support
We work with virtually any metal insert type — from standard threaded fasteners to custom stamped components.
Threaded Inserts
Brass Nuts
Metal Pins
Terminals
Bushings & Sleeves
Magnets
Stamped Metal Parts
Pre-Molded Components
Key Design Factors for Successful Insert Molding
Our Insert Molding Process
- Part & Insert Review-Analyze your part design, insert specifications, and functional requirements to define the optimal molding approach.
- DFM & Feasibility Check-Design for Manufacturability review — assessing insert placement, mold flow, and potential issues before tooling begins.
- Mold Design & Insert Positioning-Engineer the mold with precision insert locators, proper gate placement, and optimized cooling channels.
- Insert Loading & Mold Trial-Conduct mold trials with actual inserts — verifying fill, insert stability, and part quality.
- Sample Inspection & Testing-Dimensional inspection, pull-out force testing, and functional verification of molded samples.
- Batch Production & Quality Control-Full-scale production with in-process QC checks at defined intervals — ensuring consistent quality.
Common Applications of Insert Molding
From consumer electronics to automotive components, insert molding delivers reliable, durable parts across industries.
Electronic Housings
Automotive Components
Industrial Parts
Appliance Components
Tool & Handle Parts
Sensor & Connector Parts
Materials Used for Insert Molded Parts
We support a wide range of plastic and insert material combinations — carefully selected for your application requirements.
Plastic Materials
Insert Materials
Quality Control for Insert Molded Parts
Every insert molded part undergoes rigorous inspection to ensure insert integrity and part quality.
- Electrical continuity testing (for terminals)
- Insert position verification — CMM measurement
- Pull-out / torque resistance testing
- X-ray or CT scan for internal void detection
- Visual inspection for surface defects & flash
- Cross-section analysis for encapsulation quality
- Dimensional inspection per drawing tolerance
- In-process SPC monitoring during production
FAQ
Frequently Asked Questions
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