Custom Insert Molding Services

Mold plastic around threaded inserts, bushings and terminals with the mating assembly in view: where the insert sits, which surfaces stay exposed and how it carries the load.

FECISION coordinates tooling and molding through manufacturing partners. Send the insert specification and finished-part drawing together so location, retention, inspection and trial approval can be defined before manufacture.

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Production-Site Quality Review

Material & Process Matching

Project-Specific Documentation

Quantities Confirmed with Quote

Dimensional Inspection

Fecision's Insert Molding Solutions

What is Insert Molding?

Insert molding is an injection molding process where pre-fabricated components (inserts) are placed into the mold cavity before plastic injection. As molten plastic flows around these inserts, it creates a strong bond, resulting in a single integrated part. This technique allows for combining different materials—typically metal and plastic—into one cohesive component.

Unlike conventional injection molding, insert molding creates components with enhanced functionality by incorporating materials with complementary properties. Metal inserts provide structural strength and electrical conductivity, while plastic offers lightweight, corrosion resistance, and design flexibility.

Tooling for Insert Injection Molding

Our insert molding tooling capabilities deliver precision-engineered molds tailored to seamlessly integrate metal inserts with plastic components, meeting the most demanding requirements for your product applications.

Rapid Tooling

Validate the actual resin and insert interface before a larger order. Compare aluminum and steel against the insert-loading arrangement, design changes, wear areas and required sample quantity.

The first trial can investigate fit, insert movement, filling and retention. Agree the measurement and functional-test plan before sampling so each revision answers a defined question.

Production Tooling

Production tooling must locate inserts repeatedly as well as form the plastic geometry. Review wear-critical locating pins, cavity identification, loading checks and maintainable shut-off features against forecast and resin.

You can benefit from our expertise in material selection, cooling optimization, gate design, ejection strategy, and parting-line engineering—tailored to your resin, geometry, cycle time, and volume targets.

Tooling Materials

The mold tooling used in insert molding must withstand high pressures and temperatures while maintaining precise dimensions. Our tooling options include:

Aluminum

Cost-effective option for prototyping and low-volume production

Stainless Steel

Corrosion-resistant for molding aggressive materials.

P20 Tool Steel

Standard production tooling with excellent durability and moderate cost.

H13 Tool Steel

Heat-treated for extended life in high-volume applications.

Beryllium Copper

Superior heat dissipation for thermally sensitive applications

Materials for Insert Molding

We work with a wide range of materials to meet your specific requirements for performance, durability, and cost-effectiveness.
If you have specific material requirements for the project, our team can also work together to explore customized solutions.

Insert Molded Part Materials

We offer a comprehensive selection of engineering thermoplastics for the molded portion of your components.
Below shows several common types:

Part Materials for Insert injection Molding

Material	Properties	Common Applications
ABS	Impact resistant, good surface finish	Consumer electronics, automotive components
Polycarbonate (PC)	Optical clarity, high impact strength	Medical devices, electrical housings
Nylon (PA6, PA66)	High strength, wear resistance	Gears, bearings, structural components
POM (Acetal)	Low friction, dimensional stability	Precision mechanical parts, fasteners
TPE/TPU	Flexibility, soft touch	Overmolded grips, seals, gaskets

Insert Materials

The insert component provides specific properties that complement the plastic material. Common insert materials include:

Brass – Excellent for threaded inserts due to machinability and corrosion resistance
Stainless Steel – Superior strength and corrosion resistance for structural applications
Aluminum – Lightweight option with good thermal conductivity
Copper – Optimal electrical conductivity for electronic applications
Pre-molded Plastic – Used when combining different plastic types with incompatible processing temperatures
Ceramic – Provides electrical insulation and heat resistance

Insert Molding Technologies

The selected manufacturing partner reviews the press, loading method and tool layout against the part and insert drawings.
These decisions define a comparable quotation and an inspectable sample, not a generic machine-capacity promise.

Parameter	Capability	Notes
Machine and mold selection	Selected for the proposed part and insert	Review clamp force, shot volume, loading access and insert temperature limits
Shot and cavity layout	Reviewed against resin, geometry and demand	Consider fill balance and how every insert is located and checked
Part and insert envelope	CAD and drawings reviewed together	Include mating parts, insertion clearance and any surfaces that must remain plastic-free
Insert placement	Manual or automated loading assessed	Select locating features, orientation checks and handling appropriate to the order
Dimensional acceptance	Critical dimensions and datums agreed	Measure molded parts after the specified conditioning; tool accuracy alone does not establish part capability
Insert Types	Threaded, non-threaded, pins, bushings, electronics	Custom insert designs accommodated

Design for Manufacturability in Insert Molding

Optimizing your design for the insert molding process can significantly improve part quality while reducing costs and production time.
Our engineering team provides comprehensive DFM support to ensure your components are designed for successful manufacturing.

Insert Design Recommendations

Incorporate retention features such as knurls, grooves, or holes to mechanically lock the insert in place
Review plastic thickness around the insert against flow length, resin, retention loads and stress concentration
Consider thermal expansion differences between insert and plastic materials to prevent stress cracking
Design for proper insert orientation to simplify placement and prevent misalignment

Plastic Component Design Guidelines

Optimize gate locations to ensure complete filling around inserts without displacement
Select draft for the draw depth, texture and resin without compromising the mating interface
Avoid sharp corners that can create stress concentrations near inserts
Design uniform wall thickness to prevent warping, sink marks, and voids

Common Insert Molding Design Guide

Insert shifting during injection

Improve mold design with better locating features and optimize injection parameters.

Poor bonding between insert and plastic

Enhance insert surface preparation and select compatible materials.

Stress cracking around inserts

Increase wall thickness and modify design to reduce stress concentration.

Incomplete filling around complex inserts

Optimize gate location and adjust process parameters for better flow.

Utilize Inherent Benefits

Advantages of Plastic Insert Molding

Insert molding combines metal inserts with plastic in one efficient step, offering numerous benefits compared to traditional assembly methods.

Reduced Assembly Costs

By integrating multiple components into a single part, insert molding eliminates secondary assembly operations, reducing labor costs and production time, especially compared to traditional assembly methods.

Retention Designed Around the Load

Knurls, grooves and captured geometry can resist pull-out and rotation. Specify the actual loading direction, torque or pull requirement, then verify the assembled interface rather than assuming a bond is stronger than every alternative.

Design Flexibility

Insert molding allows for complex geometries and integration of multiple functions into a single component. This design freedom enables innovative solutions that would be difficult or impossible to achieve with conventional manufacturing methods.

Improved Reliability

With fewer connection points and assembly interfaces, insert-molded parts have fewer potential failure points. This increased reliability is particularly valuable in critical applications where component failure could lead to system downtime or safety concerns.

Size and Weight Reduction

By eliminating fasteners and combining components, insert molding creates more compact and lightweight parts. This weight reduction is especially beneficial in automotive and aerospace applications where every gram matters for fuel efficiency.

Assembly and End-of-Life Trade-offs

Combining parts may remove fasteners or assembly steps, but it can make metal and plastic harder to separate. Compare serviceability, scrap handling and the intended end-of-life route alongside unit cost.

Insert Molding Service for Various Industries

Insert Molding Applications

Insert molding technology serves diverse industries with applications ranging from everyday consumer products to critical medical devices.
Our expertise spans multiple sectors, delivering customized insert molding solutions for various applications.

Automotive

Electrical connectors with embedded terminals
Sensor housings with integrated mounting points
Under-hood components requiring thermal stability
Interior trim with threaded fastening points
Gear systems with metal reinforcement

Medical Devices

Surgical instruments with metal working ends
Drug delivery devices with precise components
Diagnostic equipment with embedded electronics
Implantable devices requiring biocompatibility
Medical connectors with reliable contacts

Consumer Electronics

USB and power connectors with metal contacts
Headphone jacks and audio components
Remote controls with integrated circuit boards
Power supply housings with thermal management
Wearable device components with sensors

Industrial Equipment

Control panels with embedded switches
Bearing housings with metal inserts
Pump components
Electrical enclosures with integrated mounting features

Robotics

End-effector housings with embedded threaded inserts
Servo-motor connectors with molded-in terminals
Robot joint covers with integrated metal bushings
Sensor housings with embedded electrical contacts
Control-module enclosures with molded-in mounting hardware

Aerospace

Lightweight structural components
Electrical connectors
Interior components with flame-retardant properties
Control systems with precise tolerances

Insert Molded Parts

From requirements to release

Connect insert supply, molding and assembly acceptance

Insert movement and exposed features can matter as much as the molded outline. Define the metal or other insert and its final assembled function in the same purchasing scope.

Bring to the review

Insert and molded-part drawings, tolerances and finish, supplier or supply responsibility, exposed surfaces, thread gauges, mating loads and intended resin.

Before tooling
A review of insert location, retention geometry, resin flow and loading access.
Decision to agreeResolve how the tool supports the insert without damaging functional or cosmetic surfaces.
Before the molding trial
Incoming-insert criteria and an agreed loading and identification method.
Decision to agreeConfirm which variation the mold can accommodate and which inserts must be rejected.
At sampling
Cavity-identified samples with the quoted location, thread, torque or pull-out checks.
Decision to agreeDefine fixtures, load direction and acceptance limits; distinguish destructive tests from routine gauges.
For repeat orders
Approved insert and resin specifications with the required inspection records.
Decision to agreeReview plating, insert source or geometry changes against the validated molding configuration.

Let's Start!

Bring the insert specification, finished-part drawing and mating assembly into one manufacturing review.

We are committed to providing tailored solutions that meet your specific application needs and project timelines.

Get A Quote

Insert Molding FAQs

What types of inserts can you use in insert molding?

Candidate inserts include threaded bushings, terminals, contacts, pins and custom metal stampings. Review dimensional stability, surface condition, molding temperature, pressure and locating features before approving a supplied insert.

How do you ensure strong bonding between the insert and plastic?

We use proper insert surface preparation (knurling, texturing, or coating), optimized material selection, precise mold temperature control, controlled injection parameters, and sometimes mechanical features (undercuts or grooves) on the insert.

Can you do overmolding and insert molding in the same project?

Yes. Many projects combine both techniques — for example, insert molding a metal terminal and then overmolding a second material (soft-touch TPE) in a two-shot process.

What is the minimum and typical order quantity for insert molding?

Separate validation samples, the first order and expected repeat quantities. Tool construction, insert purchasing, setup, loading and inspection determine the practical batch scope confirmed in the quotation.

How long does it take to get insert molding tooling and first samples?

The schedule is quoted after reviewing tooling, insert procurement and inspection requirements. Identify the tool-design approval, first trial, customer review, any revision and production-release milestones separately.

What should be checked before approving insert-molded samples?

Confirm insert identity and orientation, critical dimensions, plastic-free zones and mating fit. Where retention matters, agree torque or pull-out conditions, conditioning and sample quantities. Keep the results with the approved drawing and cavity identity.

What changes need a review on repeat orders?

Review any change to insert supplier, plating, dimensions, resin, cavity repair or loading method. Agree ownership, storage and maintenance of the tool, plus approval and cost responsibilities for changes before ordering.

Custom Part Application

Plastic Mounting Brackets with Threaded Inserts

Review the bracket drawing, insert specification, mating interfaces and acceptance plan together. Explore our custom injection-molded bracket application, the illustrative bracket design study, and the torque and pull-out testing guide.

Related Resources

What Is Film Insert Molding? Process, Advantages, and Design Guide

Custom Insert Molding Services

What is Insert Molding?

Tooling for Insert Injection Molding

Rapid Tooling

Production Tooling

Tooling Materials

Aluminum

Stainless Steel

P20 Tool Steel

H13 Tool Steel

Beryllium Copper

Materials for Insert Molding

Insert Molded Part Materials

Insert Materials

Insert Molding Technologies

Design for Manufacturability in Insert Molding

Insert Design Recommendations

Plastic Component Design Guidelines

Common Insert Molding Design Guide

Insert shifting during injection

Poor bonding between insert and plastic

Stress cracking around inserts

Incomplete filling around complex inserts

Advantages of Plastic Insert Molding

Reduced Assembly Costs

Retention Designed Around the Load

Design Flexibility

Improved Reliability

Size and Weight Reduction

Assembly and End-of-Life Trade-offs

Insert Molding Applications

Automotive

Medical Devices

Consumer Electronics

Industrial Equipment

Robotics

Aerospace

Insert Molded Parts

Connect insert supply, molding and assembly acceptance

Before tooling

Before the molding trial

At sampling

For repeat orders

Let's Start!

Insert Molding FAQs

Plastic Mounting Brackets with Threaded Inserts

Related Resources

What Is Film Insert Molding? Process, Advantages, and Design Guide

Overmolding vs Insert Molding: Key Differences, Materials & How to Choose

Medical Insert Molding: Process, Materials & Design Guide