This article we will cover what exactly is overmolding. We will also include the following:

  • What is overmolding

  • Why overmold

  • Materials used for overmolding

  • What is insert molding

  • Overmolding compared with insert molding

  • Differences between the two

First, let us take a look at what is overmolding.

What is Overmolding

So what is overmolding? It is an injection molding process. It creates a part using two or more different plastic materials. First, the base component gets injected. This part we call the substrate which then hardens. This substrate is then overmolded with another layer of material. Most often types we see are plastic overmolding, rubber overmolding or silicone overmolding.

Overmoulding ranges across a wide field of applications and industries. Including the automotive industry. Medical, military, overmolding electronics and more. Why is it used in so many industries? Let’s examine further.

Overmolding is when we create a part with two or more materials. We let one material harden and then overmold it with another. Such as silicone overmolding, overmolding pcb, rubber or other plastic materials.

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Why do Overmolding

There are several reasons why a consumer would like to overmold their product. Let us examine the main reasons for this:

Aesthetic – An overmolded product enhances its visual appeal. The finished piece stands out against the competition. By utilizing several colored plastics in its design. Giving it a remarkable color contrast. The manufacturer can even emboss customized patterns or logos onto the substrate.

Grip – Some items enjoy the added grip that we can design into the product. Enhancing its performance and increasing its tactile sensitivity. Think rubber overmolding on the handle of a power tool for example.

Price – The overmolding process can actually cut down on costs. Because it lowers the amount of necessary parts needed to add to the product. For the car industry, it eliminates assembly of gasket and bumper components. This removes secondary production operations like priming, paint and coating.

Comfortable – Another core factor is comfort. With overmold injection molding products, they enhance a feeling of a product. Compared with one that hasn’t been through the over molding process. Like comparing rubber overmolding on a plastic toothbrush to one without. They both work. But the overmolding process increases the quality of the product. Within the eyes of the consumer.

By overmolding electronics we protect the delicate equipment inside. Making it safe from temperatures or shock. While waterproof molding protects them from dangerous liquids. With molding tools we provide extra comfort, quality and grip.

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Overmolding Materials to Use

There are many materials which you can choose from. It is crucial to be aware of the right kind of material to use. Since different choices yield different properties when they combine. Depending on the material, it can result in different thickness effects or hardness. For injection overmolding there are many options to choose from. Including PEI, PE, PBTR, PMMA, POM, PP, PE, PC, Nylon, PEEK, HDPE, ABS and many others. Along with other thermoplastic composites.

Difference between Overmolding and Insert Molding

Overmolding is different to inset molding. This involves waiting for the primary layer, the substrate to cool first. Then combined with another plastic. But insert molding involves placing an insert, often metal, into a mold. Injected plastic then flows around it. As an example for insert molding, think of a screwdriver, hammer or USB stick. It encapsulates the metal with a single-molded and strong plastic.

When mixing plastics together we often use overmolding. When using a metal insert, that is then surrounded in plastic we use insert molding. Like a powertool handle for overmolding and a screwdriver for insert molding.

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Overmolding vs Insert Molding

Let us look at overmolding vs insert molding. Examining both their strengths and weaknesses. To determine which is best for your poduct going forward.

Insert molding is sometimes considered because it holds a variety of benefits. It cuts down on manufacturing times, because there is no need for a secondary assembly. It can create one encapsulated mold. So it is a good choice for those looking for strong parts that do not need much build time. Although it has its limitations. It can be challenging without a 3D printer to test many runs.

The benefits of overmolding are also numberous. We can make products with many materials and colors. This adds extra visual appeal elements to products not possible otherwise. It also needs less man hours and costs, compared to other manufacturing methods. Because it does not need transferring onto another machine to complete its production. It is a good choice when working with large production runs. Or with colourful designed products. But the upfront costs can be high. So producing large number of parts is the besto order to make the costs worthwhile.

Utilizing overmolding techniques we can build parts for cars even lighter than ever!

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Which is the best choice over one from another? If your product has non-plastic parts, then insert molding is a good option. But if your product contains many types of plastic or polymers then overmolding may be best for you. But your product may contain many parts making that choice more difficult. At Prototype Finder we can help with these decisions. With our consultation we can bring your next product to life. You only need to contact us and we can aid you with our injection molding processes.


In this article we have explained what exactly is overmolding. Along with the products you can most often find overmolded. Or why product developers even consider the overmolding process in the first place. If you are considering using an overmold process consider us. Prototype Finder can help you with your needs.

Are you looking for a manufacturer who can help with overmolding electronics? Or do you need someone to work with the overmolding process for your next product? Then choose Prototype Finder. We here at Prototype Finder know a great deal about overmold injection molding. Including silicone overmolding and overmolding pcb. This is because we are a prototype manufacturing and injection molding company! We have worked on over molding products for many years. We can prototype or produce an overmolded part. But can also perform low or high volume injection molding.

Should your next project include over molding? Or are you looking for some experience working with overmolding materials? If you are not sure what to do next, contact us and request a quote! Or you can indeed ask us any questions and we will be more than happy to assist in any way we can!

If you enjoyed this article make sure you take a look at some of our other posts on many other materials and topics. Including Sheet Metal FabricationHow to get Prototype Made or 3D Printing Materials for more great information.

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