2 Shot Molding – Multiple Levels of Product Can Be Manufactured in a Single Injection Mold Cycle

Two shot molding allows for multiple levels of product to be manufactured in a single injection mold cycle. This eliminates the need for secondary assembly and allows different materials to be used for aesthetic or functional purposes.

Once the first injection is made, the mold opens and rotates 180 degrees to align with the sprue of the second material. The second material is then injected over the substrate base.

Excellent Mechanical Properties

Two-shot molding allows for the use of different materials within one product to enhance functionality and aesthetics. The process can also reduce costs and assembly time by eliminating secondary processes like over molding or insert molding.

When designing a new part, engineers need to consider material compatibility during the design phase. This is important to ensure that the two plastic resins will adhere and form a strong bond. If there is a chance that the two materials may not adhere, undercuts or shoulders can be added to the design to lock the components together mechanically.

The injection molding process can also be used to create movable or moving sections of the product by injecting the softer of the two plastics first to form a shell, then filling it with the more rigid plastic. This allows for the creation of living hinges and similar components. This can be particularly useful for medical equipment such as bone saws.

Excellent Aesthetics

Unlike joining methods like welding and gluing that introduce vulnerable points in a product, 2 shot plastic injection molding produces seamless components. This gives your products a uniform appearance and enhances their overall appeal.

The two-shot injection molding process is also capable of producing a wide variety of colors and materials, making it an excellent choice for aesthetically demanding applications. It is especially useful for mixing soft and hard materials, such as silicone and thermoplastics or nylon and thermoplastic elastomers. It can even be used to create moving segments in a product, such as living hinges, by injecting a softer material first.

However, the chemistry of the two materials must be carefully considered. It is vital that the injected materials bind properly and form a strong molecular bond. This can be accomplished by reviewing a material compatibility chart and using features such as undercuts or grooves in the mold design. In addition, it is critical to keep thermal effects in mind during the product design phase.

Excellent Durability

In 2 shot molding, the first shot is molded and then the mold stays closed while a second material (overmold) gets injected. This step requires careful planning and consideration for the two materials to ensure that they can bond together effectively. Often, the second injection will need to be a softer material in order to form a “shell” around the hard plastic that forms the inner component of the part.

Also referred to as dual-injection, double-shot, multi-shot molding, or overmolding, this process allows for the production of complex parts using multiple materials in one injection cycle. This eliminates the need for secondary assembly or other processing steps which saves time and money while delivering superior product performance and durability. It also reduces manufacturing waste.

Excellent Flexibility

With a dual shot injection molding process, we’re able to mold multiple colors and use different materials. This allows for more creative designs and eliminates the need for other secondary operations such as assembly or gluing. 2 shot plastic injection molding is also much more efficient than other methods of production, allowing for a shorter cycle time and reduced material waste.

Unlike overmolding, which uses a separate machine, a two-shot injection molding machine has two injection units that feed different materials simultaneously. The first injection creates a base of hard plastic that serves as the substrate for the overmold, which is molded in a second time with softer materials like thermoplastic elastomer or liquid silicone rubber. This allows for a better combination of soft and hard materials, improving ergonomics and enhancing aesthetics, while also making products more durable by eliminating crevices where the two parts interact. Two-shot molded items are dust and shockproof, and they can even feature a soft, comfortable grip.