What Are the Differences Between Overmolding and Insert Molding?

Injection molding is a broad term used to describe one of the most important processes in manufacturing. Injection molding is a process of making typical metal tools, then molten plastic is injected into the mold and ejected.

1. What is injection moulding?

Insert molding is a subset of injection moulding technology. Before the actual injection molding, the metal part is inserted into the mold. The insert is accurately positioned in the mold by manual or mechanical arms, then the mold is closed, and the plastic is molded on the insert to form a part.

One of the most common applications of insert molding is to create metal connection points for fasteners. If the entire assembly is designed to be detachable, or if the insert molded part must be connected to a different material or part, fasteners are usually used. Metal threaded inserts molded in plastic reduce the risk of damage during installation.

2. What is overmolding injection molding?

Overmolding injection molding is essentially an insert molding. However, overmolding and insert molding are injection molding on another molded part. The first part is made in an injection mold and then placed in the second mold to add overmolding material. This technique is usually used to combine a variety of plastics to achieve practical or aesthetic purposes. For example, people may use plastics of different hardnesses to mold softer plastics over harder plastics to make the parts easier to grasp. The use of multiple colors of plastic in overmolded parts can also distinguish the product from other brands. This is usually done on the handles of tools such as screwdrivers, electric drills or toothbrushes.

3. What are the differences between overmolding and insert molding?

The difference between overmolding and insert molding: By adding the necessary metal parts to the mold, insert molding can also be used to completely eliminate the need for fasteners, thereby firmly fixing the parts to a single bonded assembly. The advantages of overmolding and insert molding are: insert molding reduces assembly costs, and injection molding machines can produce thousands of parts every day. Generally speaking, the performance of insert-molded parts is not as strong as metal parts. Overmolding can improve material flexibility. Overmolding does not require adhesives, which improves the overall durability of the part and reduces assembly costs; embedded seal overmolding provides the option of molding a soft seal into the part.