Also called multi-shot or double-injection molding, two-shot injection molding is an over-molding process that adheres additional material—like thermoplastic elastomer (TPE)—to plastic substrates to improve the appearance, grip, handling, environmental resistance, or impact resistance of injection molded components. Two-shot injection molding is typically performed by multi-barrel injection molding machines, which add extra material shortly after forming the substrate to create strong bonds between the materials.
At Fabrik Molded Plastics, Inc., we offer custom two-shot plastic injection molding capabilities. Other service offerings include precision plastic injection molding, insert molding, CT scanning, scientific plastic injection molding, automotive lighting, tooling transfers, and custom automation services.
What Is Two-Shot Injection Molding?
Two-shot plastic injection molding is an injection molding process used to create multilayer, multicolor, or multi-material parts in a single process. This process is sometimes referred to as 2K, multilayer, or multi-shot injection molding. Multi-shot manufactured products eliminate steps in the manufacturing process while creating a more cost-effective, enhanced finished product.
For bonding to occur, the two parts undergoing the two-shot molding process must be chemically compatible. Fabrik consults with customers and material suppliers to ensure proper material selection for the specific application.
The two-shot molding process improves the final product in terms of feel, color, and functionality. There are many design opportunities to suit specific preferences. Examples of two-shot injection molded products include toothbrush handles, buttons, switches, caps and closures, and hand and power tools.
The Two-Shot Injection Molding Process
The two-shot injection molding process consists of two main phases. Similar to traditional injection molding, the first phase involves injecting resin into a mold, which is then cooled to form a solid part in the shape of the mold. The second phase involves overmolding the 1st shot by transferring it to a second cavity by robot or rotating platen. The two plastic resins will form a molecular bond and, once cooled and ejected, becomes a finished multi-resin molded part.
Commonly used materials for two-shot injection molding include thermoplastics, thermoplastic elastomers, and liquid silicone rubber.
Advantages of Two-Shot Injection Molding
Advantages of the multi-shot injection molding process include:
- Lower product costs
- Decreased cycle time
- Reduction in handling and secondary processes, resulting in lower labor costs
- Complete finished product with no additional assembly steps
- Creation of complex products with improved cosmetics in a single process
- Soft-touch materials molded over a more rigid substrate create a strong and aesthetically pleasing finished product
Two-Shot Injection Molding Applications
Two-shot injection molding has a wide range of applications, including:
- Components with flexible hinges
- Multilayer thick lenses
- Dental products, such as mouth props and dental crowns
- Electric toothbrush handles
- Enclosures and caps
- Medical devices, such as bone saws, packaging, and syringes
- Multicolored components, such as switches, enclosures, knobs, and assemblies
- Plastic lenses
- Power tool handles
- Soft-touch grips
Molding Services From Fabrik Molded Plastics, Inc.
Fabrik Molded Plastics, Inc. is a custom injection and insert molding provider of thermoplastic products. We use the latest molding technologies and automation equipment in our full-service offerings to ensure we compete at the global level. Because we use the latest molding technologies and a scientific approach in our molding processes, our clients can reap the benefits of our competitive advantage. Contact us today or request a free quote to start your custom project.