The double-shot injection moulding process involves injecting two different materials into the same mold, thereby achieving the molding of a product composed of two materials. These two materials can be of different types or the same type with different colors, enhancing the product's aesthetics and assembly performance.
During the double-shot injection moulding process, a core mold and two cavity molds are required. The first injection is performed in the core mold and the first cavity mold. After molding, the mold opens, and without demolding, it switches directly to the second cavity mold for the second injection. After demolding, the double-shot plastic injection molded product can be obtained.
In actual production, typically two sets of core molds are used, with each set responsible for one injection, switching between different cavity molds by rotating 180° in the vertical direction.
Single materials often have some performance defects. Using dual-component injection molding can complement the advantages of the two materials, resulting in products with superior performance.
The plastic injection molding process is essentially the same as ordinary injection molding, consisting of injection-hold cooling. The difference is the process achieves two sequential injection moldings within a short period of time. The two materials can effectively bond together.
Reduce material costs/environmentally friendly
Enhance performance
Increase efficiency and reduce costs
Long mold life, stable quality, and lower scrap rates
Design freedom, exquisite appearance
Depending on the different usage characteristics, the core and skin materials can be freely selected without assembly, reducing seams, and solving issues with certain products that cannot be mass-produced due to special structures.
Double-shot Injection Moulding
Two plastic materials are injected into the same injection molding machine and molded twice, but the product is only demolded once. This molding process is usually called dual-material injection, typically completed by one set of molds, requiring a specialized double-shot injection moulding machine.
Over Moulding
Two plastic materials are not necessarily injected using the same injection molding machine and are molded twice. The product is demolded from one set of molds, removed, and then placed into another set of molds for the second injection molding. Thus, this molding process often requires two sets of molds and does not need a specialized double-shot injection moulding machine.
Note: The former uses a double-shot injection moulding machine, forming in one go, and can have two-color effects and different material compositions. The latter involves a single injection molding machine, extracting the first molded product and then placing it into another injection molding machine for a second forming. The former has two sets of molds and interchangeable rear molds, while the latter has no such requirement.
In short, the double-shot injection moulding process has now been widely applied in the fields of automotive, electronic products, power tools, medical products, home appliances, toys, and almost all plastic domains, playing an important role in people's production and daily life.
