LSR 2K Molding

What is 2k injection molding?

Multi-component injection molding is also called “2k molding” or co-injection molding. In order to successfully carry out the secondary molding of liquid silicone rubber, specially designed injection molding machines and skilled and experienced mold manufacturers and molders in LSR processing are needed to ensure accurate alignment and precise placement.

LSR 2k injection molding involves molding LSR material and a second polymer in the same molding process. The second material can be a compatible thermoplastic material or a different grade of LSR (different hardness or pigment). These two materials are molded and combined in the same process to form an integrated two-material assembly. This process is a secondary injection molding process

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LSR vertical 2k Molding

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LSR horizontal 2k Molding

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Radiant 2K molding

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Is 2k injection molding the same as overmolding?

Overmolding process is sometimes confused with secondary molding or called secondary molding. Although similar, because the finished components of the two are composed of two different materials or base materials, the manufacturing process and adhesion are different. In the secondary molding process, the two materials are combined chemically and physically, which provides better bonding effect than overmolding.

In the overmolding process, the finished molded parts or metal or other substrates are placed in the LSR mold during the LSR molding process. Once introduced, the mold will be closed and LSR will be molded around or on the provided substrate or component, thus integrating the two.

What are the advantages of 2k injection molding?


1.Flexibility of product design

For product designers, using multiple materials in a single component can achieve greater design flexibility, so as to achieve complex part design, ideal product functions and enhanced product performance.

Liquid silicone rubber is widely selected for sealing parts because of its excellent mechanical and chemical properties.

When multiple injection strategy is adopted, LSR seal is integrated into the part design.
For connectors, covers, valves and other parts using seals, the performance of products will be enhanced when they are produced as multi-material parts. Excellent chemical bonding is achieved, the seals are perfectly attached and kept in place, and the possible turnover or displacement of the seals when adding loose seals in the secondary assembly process is eliminated.

2.Diversity of material characteristics

When a variety of materials are used, the ideal characteristics of each material-the rigidity of thermoplastic or the weight of metal block combined with the flexibility, sealing or delicate characteristics of LSR can be realized.

By choosing a multi-injection process instead of a single material part and then assembling, hot melting, ultrasonic welding or other secondary processes for mechanically combining two or more substrates, various benefits can be realized.

3.Save cost and time

The finished product is designed by various components, and each component has the required characteristics and functions. By integrating these components and executing them in a single manufacturing process, significant savings can be achieved-saving the production cost of adding assembly or other auxiliary operation equipment, the labor cost of manual operation and material handling, and saving time.

4.Efficiency and quality

The combination of fewer production steps and cleaner and smoother material transition provides a more efficient manufacturing process. By reducing the number of operators and suppliers, the supply chain is simplified, reducing the risk and opportunity of mistakes, thus improving the quality.


Application of 2k molding LSR parts


  • Medical/dental equipment and products
  • Various multicolor parts
  • Any part containing a flexible/movable hinge
  • Products with soft tactile handles, such as staplers
  • Automobile dashboard and instrument
  • Medical/dental equipment and products
  • Various multicolor parts
  • Any part containing a flexible/movable hinge
  • Products with soft tactile handles, such as staplers
  • Automobile dashboard and instrument


Technology can realize parts weight optimization, complex design, and integrate multiple materials and functions into one assembly.

LSR secondary injection molding is very suitable for parts with strict tolerance and complex geometry, as well as parts with consistent wall thickness requirements.

Jvtech has perfected its multi-injection LSR injection technology, and is one of the few companies in China with the professional knowledge and quality results needed to meet the requirements of complex and key components. We are proud to provide customers with solutions that meet the product performance requirements of their long-term large-scale projects, and consistently provide high-quality precision multi-material components.

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Jvtech: the leader of LSR 2K molding supplier

We are proud to be a leader in the development of multiple injection molding technology. We created and implemented the technical method of functional and material integration, thus forming an unparalleled multi-injection molding process in our industry.

Our advanced tooling and molding capabilities enable us to meet the most complex design requirements without sacrificing quality, durability or aesthetics. In addition, we also provide customers with a full range of value-added services to support our multiple injection molding processes, such as front-end design support and prototyping, as well as the final secondary process, in order to obtain a complete product portfolio service.

Please contact us immediately to learn in detail that multiple injection molding can add value to your company’s manufacturing technology and application.