{"id":4091,"date":"2020-02-18T15:18:00","date_gmt":"2020-02-18T21:18:00","guid":{"rendered":"https:\/\/sybridge.com\/?p=4091"},"modified":"2024-01-18T18:46:38","modified_gmt":"2024-01-19T00:46:38","slug":"overmolding-overview","status":"publish","type":"post","link":"https:\/\/sybridge.com\/overmolding-overview\/","title":{"rendered":"An Overview of Overmolding"},"content":{"rendered":"\n

Originally published on fastradius.com on<\/em> February 18, 2020<\/em><\/p>\n\n\n\n

What is overmolding?<\/h2>\n\n\n\n

Overmolding\u00a0is a multi-shot injection molding<\/a> process that produces a single product from two or more different thermoplastics. The first \u201cshot\u201d is called the substrate, which is typically the more rigid of the two materials being used and\u00a0 is designed to accept the subsequent shots, or overmolds.\u00a0<\/p>\n\n\n\n

A variety of thermoplastics can be used for the overmold, but they\u2019re usually softer and more flexible than the substrate. The overmold material may be mixed with colorants, foaming agents, and other additives to achieve the desired effect upon completion.<\/p>\n\n\n\n

Overmolding enables the unification of the substrate material with the overmold material in a fraction of the time that it takes to join two or more parts together in a secondary operation on an assembly line. First, the substrate is injection molded out of a more rigid plastic. It is then placed into an overmolding tool or an overmold cavity within the same tool. Next, the molten overmolding material is injected into, onto, or around the substrate part. After the overmolding material cools, the substrate and overmold are chemically and\/or mechanically bonded. Quickly \u2014 often within 30 to 60 seconds\u2014a strong, durable part built from two or more complementary plastics is completed. <\/p>\n\n\n

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\"overmolded<\/figure>\n<\/div>\n\n\n

Overmolding is advantageous for manufacturers seeking to build consistently strong, durable, multi-material parts. Building one unified part from multiple bonded parts \u2014 instead of using an adhesive to bind separate parts \u2014 renders the part less likely to separate over time and improves the overall function and cosmetics of the part itself. Overmolding can also be used to make products like water-tight connector cables that comply with IP certifications.   <\/p>\n\n\n\n

Materials for overmolding<\/h2>\n\n\n\n

The materials used during the overmolding process must be chemically and\/or thermally compatible. Metal substrates can be used with any plastic overmold, but when overmolding plastic with plastic, it\u2019s possible to encounter compatibility issues. If the substrate and overmold are not made of compatible materials, the resulting product may be deformed or have poor bonding performance. If the substrate and overmold are not chemically compatible, mechanical bonding features can be designed into the part.<\/p>\n\n\n\n

Common overmolding materials include: <\/p>\n\n\n\n