2 Shot Plastic Injection Molding (Benefits and Strategies)

The global 2-shot injection molding market is gaining traction and popularity. It is a manufacturing technique that offers many benefits to a wide range of industries. It is particularly useful for creating consumer goods that require the use of mixed materials. In this case, the process can help reduce manual steps in production and ensure that all details are captured.


The two-shot injection molding process is an efficient way to combine multiple plastic materials. It also offers cost savings by reducing product assembly steps. The technology can be used for a variety of applications, including toothbrush handles, buttons, switches, and caps and closures. It also increases design flexibility and offers a range of aesthetic options. For example, it can be used to add soft-touch layers on rigid components, which improve grip and user experience.

Two-shot injection molding is also a good choice for products that require high tolerances and precision. It is important to consider all aspects of the molding process when designing a new product. This includes the materials used, transferring the substrate to the other mold cavity, and allowing for proper cooling.

Choosing the right two-shot materials is crucial to ensure successful results. The two materials must be compatible with one another and have a similar melting point. In addition, the first shot’s material should be injected before the second to avoid any possible shrinkage issues. It is also important to take into account the difference between each material’s melting point and molding temperature.

The overall cost of 2 shot plastic injection molding (another great resource attached here!) varies depending on the method used to transfer the substrate between the two cavities. Manual transfers and the use of robotic arms typically take longer than transferring with a rotating plane, but they may be more efficient for high-volume productions.

In order to keep the costs of 2 Shot Plastic Injection Molding down, engineers should optimize their mold and part designs to reduce the number of parts in each assembly. This will save tens of thousands of dollars in development, prototyping, and testing for each piece consolidated.

The growing demand for medical appliances, healthcare facilities, and durable goods is expected to drive the 2-shot injection molding market. The rising standard of living, growing disposable income, and rapid industrialization in developing regions are boosting the market. In addition, the COVID-19 pandemic has led to an increased need for high-quality and affordable medical devices that are manufactured using 2-shot injection molding machines.


Two shot plastic injection molding is a process where one material is molded into a mold, then a second, compatible material is injected into the same cavity. The result is a finished product that has the best features of both materials. For example, it can be used to create a handle that incorporates both a hard thermoplastic and a soft elastomer for gripping or cushioning. This technique allows manufacturers to use a wide range of different colors and combinations of hard and soft materials, which makes it an ideal choice for a variety of industries.

Injection molding is a complex process that requires a high level of technical expertise and attention to detail. The smallest mistakes can compound into costly problems, especially in high-volume production scenarios. This is why it’s important to work with a highly capable supplier who has extensive experience with two-shot injection molding. The right supplier will have excellent quality scorecards and defined processes to mitigate issues like flash, flow lines, and short-shots. In addition, they will be able to assist with product design to ensure that the resulting molded parts are optimized for the injection molding process.

A key advantage of 2 shot plastic injection molding is the ability to achieve a higher level of durability compared to other manufacturing technologies, such as painting. This is because the process provides a stronger, more durable bond between the different layers of the finished product. In some cases, the second layer of the molded part is actually a harder plastic than the first, which can provide added protection and resilience.

Regardless of the type of plastic used, the bonded layers in 2-shot injection molding are significantly stronger and more durable than single-shot molded parts. This makes the process a great choice for producing products that need to be sturdy and shockproof, such as power tools or electric toothbrush handles.

There are a few different methods for implementing 2-shot injection molding, including the rotary plate method and the movable core process. The rotary plate method involves using a special plate that can spin on one side of the injection molding machine. The mold itself has two sets of ejector plates and two runner systems, which are used to feed the two different materials into the cavity. The rotary plate also helps to keep the second injection process from melting or damaging the first. The movable core process, on the other hand, does not require a rotary platen and uses a normal mold with a single part and one cavity.


Two shot injection molding is a highly flexible production process. It allows manufacturers to create aesthetically pleasing products with mixed materials without the need for multiple assembly steps or expensive tooling. This type of manufacturing can be used to mold in features such as a molded-in logo, or to combine a hard plastic with a soft rubber for improved texture and design. This makes it a popular choice for accessories, such as knobs, that require both a hard, sturdy grip and a soft touch. In addition, it can be used to add a hinge, such as one formed by the plastic itself, which eliminates the need for an additional assembly step.

In two shot molding, a first shot of material is injected into the mold to create a substrate. This can be a thermoplastic or elastomeric material. Once the substrate has cooled and solidified, a second shot of material is injected into specific areas of the substrate. The two materials bond together during the cooling and solidification process to create a finished product. The entire process takes place within the same cycle, which is a significant advantage over the time it would take to make two separate cycles.

When choosing a supplier for 2 shot injection molding, it is important to select an experienced, well-vetted partner. This process requires a high level of technical expertise and attention to detail, and the smallest mistakes can cost big in high-volume production scenarios. The best suppliers will have excellent supplier quality scorecards and defined processes to mitigate issues such as flash, flow lines, and short-shots. They can also offer design assistance to help you engineer value into your final product.

While the two-shot injection molding process offers many advantages, it does have some disadvantages. The most prominent is that it is more expensive than other injection molding technologies. Additionally, the molded-in materials can be difficult to remove from the substrate. It is therefore essential that the substrate is sized properly for the second shot to ensure proper bonding and stability. It is also important to ensure that the materials chosen for the first and second shots are compatible. If they are not, it can cause warping and distortion of the substrate.


The use of 2 Shot Plastic Injection Molding opens up new possibilities for product design and allows manufacturers to create aesthetically pleasing, high-quality products. This method of production also eliminates the need for costly assembly. In addition, this manufacturing technique is highly durable and versatile. It is ideal for a range of industries, including medical equipment, tools, and toys. This technique is a cornerstone of innovation in modern manufacturing and aligns with the demands of today’s consumers, who seek functional and aesthetic products.

To achieve the 2-shot process, a standard injection molding machine is modified with two separate injection units. The first injection unit injects the primary material, while the second injects the overmold. A special shutoff, known as a raised steel cavity, is pressed into the primary mold to prevent the overmold material from oozing onto the primary part. The secondary injection also includes a support structure to prevent the overmold material from pushing the part out of shape. The support also helps to keep the pressure from deforming the primary part and is especially important for thin wall stock.

Another consideration when using the two-shot process is to ensure that the materials are compatible and will bond well. This can be achieved by careful mold design and compatibility testing. Ideally, the more rigid material should be injected first, as it will provide structural support for the more flexible overmold. It is also crucial to take into account each material’s shrinkage rate, as this can cause problems with the final result if the process is not handled correctly.

When choosing a supplier for the two-shot process, it is essential to select one with excellent technical competence and attention to detail. The smallest mistakes can cost big money, especially in high-volume production scenarios. Look for a company that offers excellent supplier quality scorecards, established processes to prevent flash, flow lines, and short-shots, and backup plans to increase capacity as your business grows.

The global two-shot injection molding market is driven by increased demand for innovative and lightweight parts that combine multiple components. The Asia Pacific region is expected to experience the highest growth over the forecast period, owing to rapid industrialization and rising consumer demand for innovative products.