Liquid Silicone Rubber Injection Moulding: The What, How, & Our Services

Key takeaways:

• Liquid Silicone Rubber (LSR) injection moulding is a precision manufacturing process used to produce flexible, durable, and high-performance silicone components.

• LSR provides excellent flexibility, heat resistance, chemical resistance, electrical insulation, and biocompatibility for demanding applications.

• The LSR injection moulding process includes material preparation, injection, curing, and finishing to ensure consistent product quality.

• LSR is widely used in medical devices, automotive, consumer electronics, industrial equipment, telecommunications, and IoT applications.

• Selecting the right material, tooling, and manufacturing approach helps improve product quality, reliability, and production efficiency.

• Flexi Versa Group supports customers with integrated Elastomeric Solutions and Precision Plastic Injection Moulding capabilities for precision silicone component manufacturing.

Introduction

Manufacturers across industries rely on Liquid Silicone Rubber (LSR) to produce components that require exceptional flexibility, durability, and long-term reliability. Its unique material properties make it well suited for applications such as medical devices, consumer electronics, automotive components, and industrial equipment.

LSR injection moulding is a specialised manufacturing process that transforms liquid silicone into precision components with excellent consistency and dimensional accuracy.

Understanding how this process works can help organisations determine whether it is the right solution for their product and production requirements.

What Is Liquid Silicone Rubber Injection Moulding?

Liquid Silicone Rubber injection moulding is a manufacturing process that injects a two-part liquid silicone material into a heated mould, where it cures into a finished component.

Unlike conventional plastic injection moulding, which uses solid thermoplastics, this process produces flexible, durable, and highly precise silicone parts. Its excellent flow properties also allow manufacturers to create intricate geometries and consistently produce high-quality components for medium- to high-volume production.

Related insights: Vertically Integrated Precision Injection Moulding

Why Use Liquid Silicone Rubber?

Liquid Silicone Rubber offers a unique combination of material properties that make it suitable for demanding applications where conventional plastics or rubber materials may not perform as effectively.

Key benefits of LSR include:

• Excellent flexibility and elasticity

• High heat and chemical resistance

• Biocompatibility for many medical applications

• Strong electrical insulation properties

• Resistance to UV exposure, weathering, and ageing

• Long-term durability and reliable performance

These properties make LSR an ideal material for products that require consistent performance, precision, and long-term reliability.

How Does the LSR Injection Moulding Process Work?

The LSR injection moulding process uses specialised equipment and precision tooling to produce consistent, high-quality silicone components. Although the exact process may vary by application, it generally follows four key stages.

Material Preparation

Two liquid silicone components are stored separately and mixed immediately before injection. Colour pigments or additives may also be added to achieve the required material properties and appearance.

Injection and Mould Filling

The mixed silicone is injected into a heated mould under controlled pressure. Its low viscosity allows it to flow easily into complex mould cavities, producing detailed components with excellent dimensional accuracy.

Curing

Heat cures the liquid silicone inside the mould, transforming it into a durable elastomer. Careful control of temperature and curing time helps ensure consistent quality and material performance.

Demoulding and Finishing

After curing is complete, the component is removed from the mould and prepared for use. Depending on the application, finishing may include trimming, inspection, dimensional checks, or quality testing.

Common Applications of LSR Injection Moulding

The versatility of Liquid Silicone Rubber makes it suitable for a wide range of industries and applications where flexibility, durability, and precision are essential.

Common applications include:

• Medical: Seals, diaphragms, valves, wearable healthcare devices, and other biocompatible components.

• Industrial & Clean Tech: Gaskets, seals, insulating components, and parts designed for harsh operating environments.

• Internet of Things (IoT): Protective seals, connectors, and flexible components for connected devices and smart technologies.

• Semiconductor: Precision elastomeric components used in manufacturing equipment and cleanroom environments.

• Telecom & Networking: Insulating parts, connectors, cable protection, and environmental sealing solutions for communication equipment.

• Electro Acoustics: Silicone keypads, vibration-dampening components, acoustic seals, and protective parts used in audio and communication devices.

Its ability to produce complex components with consistent quality also makes LSR suitable for high-volume manufacturing.

What Should You Consider Before Choosing LSR Injection Moulding?

Liquid Silicone Rubber injection moulding offers many advantages, but selecting the right manufacturing approach requires careful planning during product development.

Key considerations include:

• Product design: Complex geometries, wall thickness, and part features should be designed to support efficient mould filling and consistent production.

• Material selection: Different LSR grades offer varying levels of flexibility, hardness, chemical resistance, and biocompatibility depending on the application.

• Tooling requirements: High-quality mould design is essential for achieving dimensional accuracy, repeatability, and efficient production.

• Production volume: LSR injection moulding is well suited for medium- to high-volume production where consistency and repeatability are important.

• Regulatory requirements: Products used in industries such as medical devices may require materials and manufacturing processes that comply with applicable regulatory standards.

Considering these factors early helps reduce development risks and supports a smoother transition into production.

Also read: Design for Manufacturing (DFM): Guide to Cost Optimisation in New Product Introduction (NPI).

Supporting Precision Elastomeric Manufacturing

Manufacturing high-performance LSR components requires more than selecting the right material. Achieving consistent quality also depends on precise moulding, tight process control, and the ability to produce complex geometries with high accuracy.

At Flexi Versa Group, our Elastomeric Solutions combine Liquid Silicone Rubber (LSR) injection moulding, extrusion, and compression moulding to support a wide range of applications.

Together with our Precision Plastic Injection Moulding and Testing & Inspection capabilities, we help customers manufacture complex elastomer components with tight tolerances of 0.08–0.15 mm for medical, electronics, and industrial applications.

Frequently Asked Questions

What is LSR moulding?

LSR moulding is a manufacturing process that uses liquid silicone rubber to produce flexible, durable, and precision-moulded components through injection moulding.

What is the difference between LSR and plastic injection moulding?

LSR injection moulding uses liquid silicone rubber that cures inside a heated mould, while plastic injection moulding uses thermoplastic materials that melt and solidify as they cool. LSR offers greater flexibility, heat resistance, and chemical resistance than many conventional plastics.

What products are made using liquid silicone rubber?

Liquid silicone rubber is commonly used to manufacture medical components, seals, gaskets, keypads, connectors, wearable device components, and other products that require flexibility, durability, and environmental resistance.

Is liquid silicone rubber safe for medical devices?

Yes. Medical-grade Liquid Silicone Rubber is biocompatible and is widely used in healthcare applications. Material selection should always meet the relevant regulatory and product requirements.

Which industries use LSR injection moulding?

LSR injection moulding is widely used across the medical, automotive, consumer electronics, industrial, telecommunications, and Internet of Things (IoT) industries because of its excellent durability and material performance.

What are the advantages of liquid silicone rubber injection moulding?

Liquid silicone rubber injection moulding offers excellent flexibility, heat resistance, chemical resistance, electrical insulation, and biocompatibility. It also supports the efficient production of complex silicone components with consistent quality and tight tolerances.

Why choose LSR injection moulding?

LSR injection moulding enables the efficient production of complex silicone components with excellent precision, repeatability, durability, and long-term performance, making it suitable for high-volume manufacturing.

Concluding Remarks: Precision Moulding for High-Performance Silicone Components

Not every application requires the same material or manufacturing process. Liquid Silicone Rubber injection moulding is particularly suited for products that demand flexibility, durability, and consistent performance under challenging operating conditions.

Understanding when to use LSR—and how to optimise the moulding process—can help reduce production risks while delivering reliable, high-quality components.

Contact us to discuss how we can help bring your silicone component from concept to production.