Insert Molding/OverMolding

What is Insert Molding

Insert molding is an injection molding process in which the mold is filled with pre-prepared inserts before the molding process takes place, then molten material is joined with the inserts and they together make an integrated product. The insert is usually a simple part, ranging from a plastic handle to an electronic component.

Insert molding is widely used because there are so many applications and It eliminates the need for running any secondary operations such as soldering, welding, Connecting or bonding,which can bring down significant costs.

Types of Inserts

The insert materials can be brass, aluminum, steel, glass, etc. among them, brass is the most popular one because it’s Anti-rust, corrosion resistant, easy processing and affordable.

Based on the insert molding production quantity,there are 2 types insert operations involved. The manual one is mainly used for low-volume productions,while the automatic one will utilize robots to insert which is more reliable for high-volume production.

Below are some often used inserts:

Bolts or nuts

Electrical contacts

Spring-loaded clips

Threaded fasteners

Bearings

Overmolding & Advantages

Overmolding is a kind of 2 times injection molding in which one plastic part is molded over another already molded component,so a single part can be manufactured using two materials combination. Generally speaking, the main part is hard plastic(ABS, POM, PP, PS, PE,etc),while the outer part is soft plastic(TPE, TPR, silicone, PVC, TPU, TPV and TPEE, etc).

Overmolding is getting more popularity due to its advantages in several ways, they include:

Improved Aesthetic Appeal: we can add different colors and materials to help the products stand out in the market.

Better product Performance: overmolding parts are more shock-resistant, waterproof, and air-tight. Overmolding a part with soft material can absorb static loading or impact loading.

Reduced manufacturing Cost: Overmolding can help to reduce number of operations, through the elimination of some secondary operations like painting or coating,and sometimes plastic injection parts assemblies.

More flexible products design: Instead of complex assembly design which may include multiple parts, overmolding can put all those features on one single part design.

Insert Molding vs.Overmolding

1, Insert molding is a one step process, while overmolding is a two-step process where one plastic component is molded over another already molded part to enhance the parts performance.

2. insert molding is often bounded by metals, like brass, steel, or stainless steel. it means to adds metal parts to injection molded parts. while overmolding is 2 times injection molding,it’s combined by 2 types of plastics.

Overmolding

Insert Molding

Molds Making Projects

Shanghai Elue is an expert to provide plastic mold injection service. Over the years,we have run various plastic molds for different industries.