Injection molding is a plastic molding method commonly used for rapidly producing parts in high volumes. It is often used as an umbrella term for a few different molding techniques, including overmolding and insert molding. While both processes are similar, they also have some key differences.

Overmolding Vs. Insert Molding

Overmolding is a two-step process where two separately molded parts are combined to enhance a product’s features. They are permanently joined together but the process does not involve full encapsulation. First, a plastic component is produced using plastic injection molding. After the part is cooled, it is placed into an overmolding tool where it is then coated with molten thermoplastic or rubber.

Insert molding is different because it involves encapsulating a product in molded plastic. Insert molding is a slightly faster process because the two plastic materials are molded at the same time. During this process, the melted plastic resin is injected into a mold and a plastic piece is inserted into the mold to produce an encapsulated finished product. This technique is widely used to create aerospace and medical devices, as it enables manufacturers to mold plastic housings directly into electronics.

Using Overmolding to Meet Your Design Requirements

Overmolding layers different plastic materials on the same component for a functional or aesthetic purpose. It is used for a range of applications including medical, automotive, military and more. A common example of injection overmolding is a power tool with a strong, sturdy frame and rubberized grips on the handle. There are various overmolding material options that can be used to add color contrast or create flexible areas on rigid components.

Overmolding Material Selection

Overmolding relies on mechanical locking features or molecular bonds that form between the layers of plastic. Because of this, one of the most important considerations in the overmolding process is material selection.

Overmolding material and the substrate material must be compatible, enabling the two materials to form chemical and physical bonds during fabrication. Their effective bonding helps to ensure that the part is durable. Incompatible materials could lead to deformations or part failure.

To learn more about overmolding materials for your product or prototype, contact Bangor Plastics today at (269) 427-7971 or you can send us an email at bangorplastics@bangorplastics.com. You can also submit product specs and upload your designs here: https://bangorplastics.com/get-a-quote/