Overmolding Vs Insert Molding-Differences In Manufacturing Processes

There are many different types of manufacturing processes, and it can be difficult to decide which one is right for your product. Both of these types of production are the sub-processes of Injection molding, that is why some people may get confused as to what these manufacturing processes can do and what are their differences? Do they have their own unique style of processing?

In this article, we will compare overmolding vs insert molding and discuss the differences between the two processes. Overmolding is essentially a type of insert molding. However, overmolding vs. insert molding is, as the name suggests, plastic is molded over another molded part. The first component is made inside an injection mold, and it is then placed into a second mold to add the over-molded material. So, which process is right for you? Keep reading to find out!

Specifying overmolding vs Insert molding

What is overmolding?

Overmolding starts with a single material that is injection molded to create the first layer. The second material is then injected on top of it, creating a bonded joint between the two materials. Overmolding can also be done with multiple materials, but it typically involves two. In simple terms, Overmolding is a plastic injection molding process that combines two materials in a single product. Usually the materials that are being combined in a product is a thermoplastic elastomer (TPE), which is a rubber-like material, and some soft materials that are comfortable to hold on to. These materials are over a hard substrate.


What is insert molding?

Insert molding is the process of placing a pre-made component into an injection mold before adding the material that will surround it. This can be done with one or more materials, and it’s often used when multiple colors or materials are needed in one product. Insert molding is also used to add strength or support to products that would otherwise be too weak. The premade component is typically made of metal, but it can also be made of plastic or another material. This type of process can be used manually or automatically. Manufacturers typically use the automated insert molding as they can reduce labor and also reduce potential errors made by the workers.

Insert molding

Differences in manufacturing process of overmolding vs insert molding 

There are many differences in manufacturing processes between Overmolding vs Insert Molding,  but the main difference is in how the products are made. Overmolding is a two-step manufacturing process that starts with injection molding one material, then adding another material on top of it. And because this process is a two-step process it is more costly than Insert molding. On the other hand, insert molding is a one-step manufacturing process that involves adding parts to the molded part prior to the part being finished, especially metal parts, which are included in the process of insert molding. Insert molding is less costly than Overmolding, and it can be done manually or automatically.

So, which process is right for you? If you need a product that is made of two materials, then overmolding is the way to go. If you need a product that is made of one material with parts added to it, then insert molding is the way to go. And if cost is a factor, then insert molding is the less costly option. Overmolding is also a good choice if you need to add texture or another design element to your product.

The benefits and downsides of overmolding vs insert molding

Overmolding vs insert molding benefits


Insert Molding

Can make a non-slip grip on top of another material – Aside from the comfort it provides when using it. Overmolding materials (thermoplastic elastomers) are also capable of absorbing unwanted vibrations and protecting the user from excessive heat or electric shock.Cost-Effective – Insert molding process can be used to eliminate the cost for complex assemblies, as well as the labor cost for automated insert molding.
Material Flexibility – This allows the designers to freely use the advantage of overmolding to create complex parts and improve the appearance of the product that can boost the image of their business.Increases Reliability – Before cooling, the plastic flows easily around each insert. Parts are less prone to become loose or misaligned, and they are less likely to shatter, when inserts are tightly held in plastic.
Durability – The overmolding process increases the durability of the materials without using any adhesives.Design Flexibility – Designers can incorporate features into plastic parts that will enhance their strength, durability, and reliability.

Overmolding vs insert molding downsides


Insert Molding

Costly – It requires two separate molds.Labor costs – It is costly if it is manually inserted
Debonding – It can expose two materials to delamination risk.Compatibility – The mold can be damaged if the design is not compatible with the insert mold.
Requires specialized Equipments – As this process requires a two-step process it may require other equipment for  you to use. Bulk buying is not available – As order quantities increase, the process becomes more difficult to scale

In conclusion,  Overmolding vs Insert Molding are two different manufacturing processes that have their own benefits and downsides. Overmolding is a two-step process that is more costly, but it offers more design flexibility and can be used to create products with two materials. Insert molding is a one-step process that is less costly, but it requires specialized equipment. When choosing a manufacturing process, it is important to consider the type of product you need, the quantity you need, and your budget. Overmolding and insert molding are both viable options for many products, but one may be better suited for your needs than the other.

Overmolding vs insert molding FAQS

What are the applications for overmolding and insert molding?

Overmolding is commonly used in solar energy, military equipment, consumer electronics, medical equipment, as well as in industrial and OEM applications. While Insert molding is used in military equipment, medical instruments, Threaded fasteners, Home appliances, electrical devices and many more.

When should I use overmolding?

Overmolding is often used when there are parts of a product that are needed to have a stronger grip in some parts and to make the product heat and electricity-resistant parts that need to be held in the hand.

When should I use insert molding?

It is recommended to use insert molding whenever a plastic case is occasionally opened for service, followed by locking it tight again, as might happen when performing routine maintenance or changing batteries in a device. 

Why should I use Go4mould’s overmolding and insert molding?

Despite the more complex design, processing, and material selection required for overmolding and insert molding, there are many advantages: 

  • Combining materials provides characteristics that no single resin can match.
  • It saves time and money by eliminating assembly steps.
  • Unlike assembly processes, it can meld materials like no other. 
  • Parts with inserts are stronger and more durable.

Now that you know the difference between Overmolding vs Insert Molding, and the benefits and downsides of each process, you can decide which manufacturing process is right for your product. 

Go4mould is the leader in plastic injection moulding in China. We are well established in the process of Overmolding and Inset molding. We would be happy to answer any questions you may have about these processes, or any other manufacturing processes, or if you would like to know more information about them. Contact us if you have any questions.

Scroll to Top