06 Jul 2020

What is Insert Molding?


Insert molding is the process of injecting plastic around an object, usually metal. This creates a single piece using two or more materials. Common inserts include things like metal pins and threaded rods.


Why use insert molding?


Insert molding is widely used in manufacturing today because it allows for a great deal of versatility in products. Instead of creating a piece entirely out of metal, insert molding allows designers to create a product that uses metal only where it’s needed most. This process creates pieces that are durable and cost-effective, combining the strengths of plastic and metal.

Compared to installing a metal portion into a completed plastic part, insert molding is considerably cheaper and more efficient.

A small screwdriver with a metal driver and plastic handle; demonstrating a use of the insert molding process

Insert molding vs overmolding


Overmolding is a process by which two or more different materials are used to create a single product. Overmolding allows manufacturers to create pieces that combine the strengths of different plastics. One common example would be a simple toothbrush, featuring a hard plastic core and a soft, rubber-like grip.

While both techniques are used to create products out of multiple materials, they are completely separate processes, used to create completely different products. You can read more about overmolding here.

Threaded inserts


If a product is going to require screws, insert molding is one of the best solutions available. Using a threaded metal piece allows an otherwise plastic product to have the torque performance and pullout resistance of a metal one. These parts are designed to improve the overall strength of a product and increase its load-bearing ability. Including a threaded metal insert can increase the lifespan of any assembly that will be frequently disassembled and reassembled.

There are countless other possibilities for this process too; essentially anything that can be secured firmly during molding without suffering any damage can be used.

The Rex Plastics Advantage


Rex Plastics has the experience and expertise to help you create exactly what you need. Moreover, we’ll work with you through design, prototyping, and production to ensure the highest quality product at the lowest possible price. In addition, Rex Plastics is a full-service plastic injection molding manufacturer; you can walk in with an idea and end up with a product ready for distribution. If you’d like more information about plastic injection molding with Rex Plastics, contact us today.

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