Two-shot molding, also known as dual injection molding and two color injection molding, allows for a mix of different materials in one machining cycle. This provides designers with more options to create innovative parts.
The 2 shot process begins with a substrate that is molded in a tool, then moved manually or robotically to another cavity where it receives the overmold. The two resins then molecularly bond together and the finished part is ejected.StrengthWith 2 shot injection molding, manufacturers can produce two levels of the same product in one machine cycle. This saves time and money. It also helps ensure that the components are joined together correctly. The process eliminates the need for gluing or welding, and it provides better mechanical properties than conventional products and other advanced processes such as insert molding.The 2 shot process is especially effective for creating ergonomically designed products. For example, it allows designers to incorporate structural plastic areas with softer, more appealing materials. These can include rubbery seal surfaces on toothbrushes and soft grip surfaces on storage containers.The key to successful 2 shot manufacturing is finding a qualified supplier that understands the unique needs of this type of production. Look for a supplier with a strong supplier quality scorecard and defined processes to mitigate flash, flow lines, short-shots, and other common issues. They should also be able to identify problem points during the design phase to engineer value into the product.DurabilityUnlike traditional injection molding, where knit lines (small hair-like discolorations) may form in areas where two different flows of plastic meet, 2 shot allows for the integration of multiple materials with no seams. These smooth transitions increase the strength and durability of molded parts. This makes the process especially useful for products that will be used by humans.This multi-material process also eliminates the need for additional assembly processes like gluing and welding, cutting down on production costs and labor requirements. Additionally, since components are molded together at the same time, there is less waste.This process is commonly used to manufacture durable, visually appealing and ergonomically designed products. It enables the combination of thermoplastic and LSR material, allowing manufacturers to achieve functionality that would be difficult or impossible to make with conventional injection molding. Examples include handles and switches on household appliances. It also allows for the inclusion of soft, rubbery materials to enhance gripping and handling capabilities.AestheticsTwo shot molding, also known as double injection molding and dual injection molding, is a plastic injection molding process that allows you to combine different materials in one component. This makes it ideal for building strong, functional and aesthetically pleasing parts that won’t separate over time.Similar to overmolding, the process begins by injection molding a substrate base of more rigid material. Then, a second molten material called an overmold is injected around the base and chemically or mechanically bonded to it. The resulting component is then cooled and ejected.The 2 shot process is also compatible with soft materials, allowing you to design ergonomic components like handles and knobs. This helps manufacturers produce products that meet consumer demands for functionality and comfort.As with any molding technique, it’s important to choose a capable supplier. Look for a partner with a proven quality record, defined processes to mitigate against flash and short shots, and contingency plans to expand capacity as your needs grow.FlexibilityTwo-shot injection molding allows the product designer to use multiple materials. The engineer can combine the good structural properties of an engineering plastic with the soft and appealing nature of a different material in a single process. The result is a strong and durable, yet attractive, product.The first step of the process is very similar to traditional injection molding: a shot of resin is flowed into one cavity of the mold and allowed to solidify and cool. Then the mold is rotated (manually or robotically), allowing the sprue of the second resin to align with a cavity in the same tool. This new resin is then molded in, through or around parts of the first shot and molecularly bonded to it.This multi-shot process offers very accurate manufacturing. There is no need to remove the semi finished product from the mold in between steps, reducing the chance of thermal effects misaligning components. Two-shot injection molding also allows for very tight tolerance.2 shot molding
