In injection molding, 2 shot is the process of injecting two different plastics into one tool at the same time. This allows a product to be molded with a hard material, like an engineering plastic, and then injected with a soft or appealing material, such as elastomer, to make the final product. This gives the end user a more functional and appealing design, while still being able to enjoy the structural benefits of the original material. The two shots can be molded in one mold or multiple separate molds.
A good injection molding company can do a great job with this process, but it is not without its challenges. The main challenge is ensuring that the different processes run seamlessly together. This requires a large amount of planning and coordination between the production team and the injection molding machine. There are many different components of the process that must synchronize with one another, such as screw rotation, firing of shots, and mold rotation. It also requires a solid understanding of how the different materials behave.
Once the first injection of resin is molded, a separate injection unit fires a second shot of resin over the molded first section of the part. This second shot fills over the first injection and hardens. The two sections must be chemically comparable for bonding to occur. In most cases, the injection of the second section must be done in a manner that makes it easy for the injection unit to transfer the substrate to the second injection area. This can be accomplished with a rotating platen, a robotic arm, or a combination of both.
The result is a highly accurate product. Since the semi finished product does not need to be removed from the mold between steps, there is no chance for error or misalignment in the material. This is a huge advantage over other injection molding processes and can be the difference between a successful and an unsuccessful project.
The use of 2 shot injection molding offers an incredible amount of design freedom for the engineer and designer. It can allow for the mixing of a number of different materials that would not be possible in any other way. This allows the user to enjoy the durability of a strong engineering plastic with the soft feel and color options that a more appealing or aesthetic material can offer. It is a great option for projects that require both functionality and attractiveness. Ultimately, it is best to partner with an injection molding company that has a demonstrated history of success with this process and the ability to understand the product requirements well enough to be able to offer sound engineering advice. This can help to ensure that the best and most cost effective solution is achieved. This can save both time and money, as well as a great deal of frustration for everyone involved. 2 shot molding