Insert Injection Molding Services

Injection Molding of Pump Housing using Carbon & Glass Reinforced Polyamide

Insert injection molding is the process of forming plastic around a non-plastic insert, which can be as simple as a metal rod or as complicated as a battery. When plastic is molded onto the insert, the two components augment each other, resulting in a more reliable final product that offers advantages from both materials. Usually, engineering plastics are used for insert injection molding because of their superior characteristics, such as their resistance to damage, their tensile strength, and their low weight.

At Plastic Design International (PDI), we provide in-depth, comprehensive insert injection molding services and work with various plastic grades, including both consumer and engineering grade plastics. We also operate 21 different molding machines, including robotic sprue pickers, automated conveyors, coordinate-measuring machines (CMMs), and a vertical press that uses a rotary table and engineering-grade plastics. Our advanced setup and over 40 years of experience allow us to handle even the most complicated assignments with reliability and precision.

Vertical Presses with Rotary Tables

Compared to horizontal molding machines, vertical presses are usually more versatile and efficient. At PDI, we pair our vertical press with a rotary table, which allows us to make the mold and insert the part at the same time. A rotary table holds two B halves of a mold so the operator is able to add inserts to one B half while the second B half is molding product and mating with the A half. Vertical presses that use rotary tables are precise and methodical, making them ideal for processing complex inserts.

Engineering Grade Plastics

Commodity plastics can be used in many different applications. However, they are relatively weak, unsuitable for high temperatures, and susceptible to chemicals.

Engineering-grade plastics, on the other hand, have better mechanical and thermal properties than commodity plastics. They are durable, fire-retardant, and chemical-resistant, making them perfect for specialty applications such as those found in the medical and safety industries. Examples of engineering grade plastics available with insert injection molding include:

Insert Injection Molding vs. Injection Molding

Insert injection molding and injection molding are similar processes, but inserts add durability and strength. For example, two plastic components that mate together to form a hinge can be made with standard injection molding. If the components are going to be used in a weight-bearing application, however, metal inserts are needed to create more stability. Components made with insert injection molding are stronger than standard plastic parts but still lighter and less prone to corrosion than metal.

Overall, inserts are used in applications where characteristics of both the plastic and the insert material are needed.

What Is the Difference Between Insert Injection Molding and Overmolding?

Overmolding is a compounding process that molds an additional layer of plastic over a previously molded component. Additional inserts are not incorporated into the component for the purpose of augmenting it like they are during insert injection molding, which is also only a one-step process.

At PDI, we offer injection molding, insert injection molding, and overmolding to address our customer needs. At this time, we don’t provide two-shot injection molding.

Having Trouble Deciding Which Injection Molding Process Is Right for Your Application?

Injection molding processes are somewhat similar, but certain methods are best suited to specific applications. Injection molding usually works better for creating simple, lightweight components that are cost-effective; insert injection molding is best reserved for products that demand durability and are more expensive to produce; overmolding is ideal for components with multiple layers.

For help deciding which injection molding process you should use, contact Plastic Design International. If you already have an idea about what you need, request a quote online today and we’ll respond as quickly as possible.

Insert Injection Molding Capabilities:

General Capabilities
Injection Molding
Custom Fabrication
Mold Making
24/7 Lights Out Operation
Global Clientele
Material Requirement Planning
Inventory Control
3 Shifts
Insert Molding
Engineering Changes
In-House Mold Maintenance
Product Capabilities
Small to Medium Parts
Low Volume
High Volume/Low Mix Capabilities
Insert Molding
Mold Process Type
Custom Insert Injection Molding

Engineering and Commodity Thermoplastics grades including but not limited to;

Copolymer Polypropylene
Polyaryletheretherketone (PEEK)
All thermoplastic materials except PVC, Silicone, & PTFE
Temperature Range
Melt temperatures up to 800°F
Machine Maximum Velocity
Up to 12 in/sec
Clamp Tonnage
35 tons
385 tons
Shot Size
The maximum weight of plastic that can be displaced or injected by a single injection stroke. Generally expressed as grams of polystyrene.
Up to 676 grams of PS
Number of Cavities
The number of cavities in the mold used to produce multiple products in one molding cycle.
1 to 32 cavities
Work Space Capacity
55,000 square feet
Part Thickness
.020 and up
Tolerance (+/-)
Secondary Services
Part Assembly
Hot Stamping
Heat Staking
Sonic Welding Parts
Hardness Testing
Leak Testing
Moisture Testing
Force/Break Testing
Destruct Testing
Continuity Testing
Part Decorating
Surface Finish
Mold customer texturing and engraving
Additional Services
APQP – Advance Product Quality Plan
Process Validation
Dew Point Controlled Facility
CNC Machining
Electric Discharge Machining (EDM)
Mold Acquiring Capabilities
Mold Evaluation
Mold Maintenance
Mold Making
  • Domestic Tooling
  • Overseas Tooling
  • Tool Design
Product Development Assistance
Mold Flow
  • CMM Inspection
  • Optical Measuring Machine
Production Volume
Low Volume
Small Run
High Volume
Large Run
Long Run
Lead Time
Quoted on job by job basis
Rush Services Available
Just- In Time/ Ship To stock

Additional Information

Industry Focus
Consumer Goods
Fire Safety
Fire Arms
Industry Standards
ISO 9001:2015 - International Organization for Standardization
TS - TS Is a quality standard developed by the Automotive Industries.
RoHS - Restriction Of Hazardous Substances (Compliant)
WEEE Compliance
Material Composition Declaration IPC 1752
ITAR - International Traffic In Arms Regulations
Proposition 65
Lights Out Manufacturing
3 Shifts
File Formats
Preferred format is SolidWorks, but we can also accept;
DXF - Drawing Interchange Format, or Drawing Exchange Format
IGES - Initial Graphics Exchange Specification, ANSI file format.
Inventor (IDW, IPT)
JPG or JEPG - Joint Photographic Experts Group
PDF - Portable Document Format
Pro-E or Pro/Engineer (DRW,PRT,XPR)
SolidEdge (DFT)
STEP - Standard for the Exchange of Product Model Data

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