Overmolding VS Insert Molding

Two common methods of manufacturing plastic parts are overmolding and insert molding. In overmolding, a two-part mold is used in which the inner part is for forming the basic shape of the part and the outer part provides the desired finish. The two parts are then joined together, and the plastic is injected into the space between them. The debate between overmolding and insert molding is one that plagues many small businesses. Each process has its own unique benefits, so it can be difficult to decide which route to take. The plastics manufacturing process known as insert molding is a process where a preformed metal or plastic part, also called an insert, is placed into a mold cavity. Molten plastic is then injected into the cavity around the insert, and the part is molded to shape.

What are the benefits of overmolding?

The benefits of overmolding are many and varied. Overmolding provides manufacturers with a number of advantages, including adding strength to the assembly, protecting the parts from harsh chemicals or environments, and decreasing manufacturing costs. When selecting an oversold partner, it is important to consider factors such as experience, engineering resources, and quality control. By choosing an experienced and reliable overmold partner, manufacturers can realize all the benefits that overmolding has to offer. There are many benefits to overmolding, which is why it is such a popular manufacturing process. Some of the most notable benefits include:

  • Improved part quality
  • Reduced production costs
  • Increased production efficiency
  • Improved product reliability

How does insert molding work?

How does insert molding work? This process begins by creating a positive and negative mold of the desired object. The positive mold is then filled with a liquid plastic, which is cured and becomes the object’s outer layer. The negative mold is then filled with a harder plastic, which acts as an inner layer. After both molds have been hardened, they are joined together, and the inner layer is injected with air pressure.

  • Insert molding is a process used in manufacturing where a pre-molded part or insert is placed into a mold cavity and then the molten plastic is injection molded around it.
  • The insert can be made from a variety of materials such as metal, ceramic, or glass.
  • The insert molding process is often used to produce complex parts that are not possible with other molding processes.
  • In addition, because the inserts are produced separately, this process allows for more intricate designs and a greater degree of customization.

Injection molding is a manufacturing process for producing parts from both thermoplastic and thermoset plastic materials. Molten plastic is injected into a mold cavity, where it cools and hardens to the shape of the cavity. After ejection from the mold, the part may undergo further processing, such as trimming, welding, or assembly.


The debate between overmolding and insert molding is one that is frequently asked by manufacturers. Which process should be used for their product? The answer to this question largely depends on the factors involved in the production of the product. There are a variety of benefits and drawbacks to each process that must be considered.