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  • Writer's pictureEmerick Varga

Plastics 101: Everything You Should Know About the Process of Overmolding

Overmolding is a unique and popular process where two different materials combine to make a single product. The two-part process uses a substrate or base material, generally a rigid and durable plastic, and covers it either completely or partially with a softer material (mostly TPE). The process may sound simple, but it has massive potential for industrial applications, making it a popular choice among different manufacturers.

Types of Overmolding

Depending on the application and requirements of your project, you can choose between different types of overmolding. In almost all cases, the covering material is softer and lighter than the substrate, and the two parts are either chemically bonded or mechanically interlocked with each other.

Following are the four different types of the overmolding process:

  • Plastic over plastic

  • Rubber over plastic

  • Plastic over metal

  • Rubber over metal

The Best Materials for Overmolding

For overmolding, material compatibility and physical properties stand as the most critical factors. Most of the materials in this process are chemically bonded, and incompatibility will either fail or give you an inferior product. You also have to consider your final products and make sure that you are selecting a suitable material. Some choices are only suited for specific conditions, which naturally limits their applications.

We recommend relying on specialists who know the important characteristics like mechanical properties, bonding, material behavior, etc.

Some of the most common choices for overmolding in the industry are:


High-Density Polyethylene is your go-to material for durability and toughness. The service temperature of this material is around 1830 F, making it ideal for a variety of applications. Similarly, HDPE can be quickly processed and can even resist moisture.


One of the most common materials you'll encounter in any overmolding facility. ABS is an excellent choice for many applications due to its toughness, ductility, heat resistance, and the ability to work with most acids and alkalis. You'll often find ABS in electronic products, some automotive components, and smartphones.


Polyetheretherketone (PEEK) is engineered to perform in the harshest environments. This material is the perfect choice for applications where you need great thermal, chemical, and mechanical properties. The high-profile plastic is used in gaskets, automobile engines, pumps, compressors, and other similar components where regular material immediately fails.


Acrylic is another standard plastic we deal with regularly. From optical lenses to touchscreens and lamps, you'll find Acrylic everywhere. The surface of this material is considerably hard, and it possesses moderate tensile strength. The material has excellent transparency and is quite economical as well. Moreover, Acrylic and PEEK are among the very few FDA approved materials, which makes them suitable for the food and medical industry.

The above list names only a few most commonly used options that work well with others. There are numerous material options and combinations, which are almost impossible to list down. The important thing to remember is that having the correct combination is essential for overmolding applications. You have to be extra careful when choosing the material combination for your process.

Why should you choose Overmolding?

In the current consumer market, multiple sectors rely on the overmolding process to make their products attractive, practical, and safer. From sensitive medical instruments to your child's favorite toy, overmolding is used because of its various advantages. Some of them are discussed below.

Better Performance

The most significant advantage you'll get with overmolding will be the increase in your product's performance. Most slip-resistant grips, soft handles, and other add-ons are possible because of this process. They are a perfect choice for applications where you can't compromise on the user's comfort and the material strength.

Electrical Insulation and Vibration Absorbance

Building on the performance aspect, overmolding also contributes to making your product safer. The process can help you create insulated handles and covers that can protect users from burns and electric shocks. Additionally, vibration dampening is another area where overmolding can help manufacturers. Having molded dampeners on the vibration source will give you better protection and increase your product's durability.

Reduced Overall Costs and Production Times

Another significant benefit of the overmolding process is the overall reduction in cost and production times. This process can reduce the assembly-line time, which increases efficiency and reduces the total running costs of the manufacturing setup.

Increased sales and customer retention

There is a cut-throat competition in the consumer industry, and manufacturers need to do everything they can to make their products stand out. Overmolding helps by enhancing the performance potential of a product, but that's not all. The process also makes it possible for you to increase the visual appeal with bright colors and attractive finish. The functional and visual aspects combine to increase the shelf appeal of your product, which will result in increased sales and more revenue for you.

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