LSR 2-Shot Injection Molding (Multishot)

LSR 2-Shot Injection Molding

SIMTEC Silicone Parts is a leading supplier of multi-shot injection molded parts for the automotive, healthcare, and consumer goods industries, among others. 2-Shot molding is a versatile process that can be used to create parts in a wide range of sizes and technical configurations.

Our advanced production capabilities allow us to meet complex design requirements and exceptionally high quality control standards. We also offer a full selection of value-added services, including prototyping, secondary processes, packaging, and more.

What Is Multi Component Injection Molding?

LSR 2-Shot molding or multi-component injection molding is sometimes referred to as overmolding, assembly injection molding, or twin shot. In general, this process consists of overmolding LSR directly onto a thermoplastic substrate immediately after the thermoplastic substrate has been molded, in the same mold and with the same injection molding machine. This process allows for the integration of several functions, parts and materials into one component, fused permanently.

Two-part silicone rubber molding also allows for the best features of both materials to be taken advantage of, while simultaneously reducing or eliminating the need for post-molding assembly operations. Additionally, initial investments are reduced, as only one tool is required to produce the component. Qualification and inspection costs for the tool and product are also reduced.

LSR 2-Shot Injection Molding


2-Shot injection molding requires first the creation of a mold, or the modification of an existing mold. This is typically the most expensive and time-consuming part of the process. Once the mold has been made, production can begin.

2-Shot injection molding involves a single machine cycle, making it a fast and easy way to create more complex parts. First, LSR is injected into the initial mold. Then, the secondary mold is placed on top, and a second shot is administered. Individual parts can be completed in as little as a few minutes and, because it’s done in a single process, the overall lead time for a larger project is shortened.

With the right machinery, two shot molding can achieve extremely high tolerances, making it an excellent choice for demanding applications where precision is required. Speak with a SIMTEC representative directly for more information.


The 2-Shot molding process can have a number of benefits when making various components:

  • 2-Shot molded parts have greater integrity. The 2-Shot injection molding process creates a stronger, tighter seal without the need for additional gaskets or other components. This makes it an excellent choice for any product where water-tightness is required.
  • 2-Shot molded parts have a more attractive appearance. As opposed to single-shot components, the ability to use multiple colors adds visual interest and makes a product appear more expensive and higher quality.
  • 2-Shot molded products are more comfortable. The 2-shot process allows you to overmold a soft handle or grip onto a hard plastic. This can be used to create items that are more ergonomic and comfortable for end-users.
  • The 2-Shot molded process offers better quality control. Because the overmolding process is automated, there’s less room for error and less likelihood that a small or fragile component will break during assembly.

The best way to get the most benefits from the 2-Shot injection molding process is to work with a provider who has experience and expertise. That’s where SIMTEC comes in.

Our Production Capabilities

Here at SIMTEC we pride ourselves on being at the forefront of LSR 2-Shot (LSR/thermoplastic) technology, and make every effort to remain a leader in LSR and LSR 2-Shot injection molding technology. We are continually investing in this technology and our fleet of injection molding machines includes one of the first, as well as one of the largest, LSR/thermoplastic injection molding machines (with a clamping force of 350 tons) outside of Europe. We are ready to apply our unique area of specialization to your application(s), customizing each step of the process to create a superior end product that makes the most of the inherent benefits of both our LSR and our LSR 2-Shot injection molding processes.

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Value-Added Services

SIMTEC does more than just produce quality 2-Shot injection molded parts. We can also assist with all aspects of the design and the customization of the production process, providing consulting services that leverage our years of experience in the silicone parts industry.

Whether you need assistance choosing the right raw material for your component or are looking for the most economical way to ship your finished product to overseas markets, we can help. You will also benefit from our exceptional quality control processes, which allows us to deliver one of the lowest defect rates in the industry.

Why LSR 2-Shot Injection Molding?

LSR 2-Shot technology allows for part weight optimization, complex designs, the integration of multiple materials and, when needed, multiple functions into one component. LSR 2-Shot injection molding is well suited for parts with tight tolerances and complicated geometries, as well as parts with wall thickness consistency requirements. With this process, we are able to provide solutions that ensure the repeatable production of high precision, high-quality parts for large volume applications.

Specific Industry Applications

Multi-component injection molding is perfect for any application requiring two-part silicone rubber components. SIMTEC has a long history of collaborating with Fortune 100 and Fortune 500 companies to produce parts for the following industries:

  • Automotive — The 2-Shot injection molding process greatly reduces or eliminates the need for additional assembly, making it an excellent choice for economically creating LSR/plastic or LSR/metal automotive components. For example, multi-component injection molding is often used to create wiring harness components, where the product housing, grommet, and ring seal are all manufactured within the same mold.
  • Health/medical — 2-Shot LSR molding can be used to create complex, multi-component parts for the healthcare industry. Because LSR is hypoallergenic, bacteria-resistant, and extremely biocompatible, it is suitable for use in specialized surgical or medical applications.
  • Consumer goods — Any consumer product requiring airtight/watertight seals and gaskets can be a candidate for LSR two shot molding. LSR’s insulative and environmental sealing properties make it an ideal choice for housings, dampers, and many other components.

More information about the different forms of LSR 2-Shot injection molding can be found in our blog entry titled LSR 2-Shot Experience and Expertise. To discuss the specific needs of your project with our team, and to obtain a free quote, contact a SIMTEC representative by phone or email.

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