Gemini provides specialist Liquid Silicone Rubber (LSR) injection moulding services in the UK, supporting customers across medical, automotive, industrial and performance engineering sectors.
LSR is a high-performance elastomer known for its durability, flexibility, and resistance to extreme environments. Our in-house capability allows us to deliver both rapid prototyping and medium volume production, giving customers a seamless route from development to manufacture.
By combining advanced process control with decades of silicone expertise, we produce precision-moulded Liquid Silicone Rubber components engineered for reliability and repeatability.
Our Unique Liquid Silicone Rubber Prototyping System
We operate a uniquely developed speed mixer system specifically designed for prototype silicone mouldings.
Unlike traditional LSR machinery — which can require hours of downtime and generate significant material waste when changing silicone grades — our system allows material changeover in seconds with virtually no waste.
This provides several key advantages:
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- Rapid iteration during product development
- Incremental hardness sampling for valves and seals
- Reduced material waste and lower development costs
- Faster validation of functional performance
This flexibility enables engineers to refine component performance efficiently and accurately before committing to production tooling.
Medium Volume Liquid Silicone Rubber Production
To complement our prototyping capability, we have invested in a dedicated BOY 55 LSR injection moulding machine for consistent, cost-effective production.
This enables us to offer:
- Medium volume manufacturing
- Tight process control and repeatability
- Improved cycle efficiency
- Greater consistency across production batches
Customers benefit from a scalable solution that maintains quality standards from initial prototype through to full production.
Advanced 2KM Mixing System with Colour Dosing
This machine has been retrofitted with a 2KM mixing system, enabling automatic colour dosing at the point of injection. This capability provides:
- Greater flexibility for material changes
- Accurate colour consistency
- Reduced downtime between production runs
Colouring LSR at the injection stage enhances both efficiency and customisation, supporting diverse product requirements.
Silicone Over-Moulding onto Thermoplastics
Gemini has developed a specialist process for over-moulding silicone onto thermoplastic substrates.
Through carefully controlled surface treatment, we achieve a permanent bond between the silicone and plastic component. This capability is ideal for applications requiring:
- Soft-touch interfaces
- Sealed assemblies
- Enhanced grip surfaces
- Integrated valve and sealing systems
Silicone over-moulding expands design possibilities while maintaining structural integrity and long-term durability.
Benefits of Liquid Silicone Rubber (LSR)
Liquid Silicone Rubber offers a wide range of performance advantages:
Mechanical Performance
- Extremely elastic
- Superior tensile strength
- Excellent compression set resistance
Environmental Resistance
- UV resistant
- Ageing resistant
- Chemical and bacteria resistant
- Performs reliably from -55°C to +300°C
Safety & Compliance
- Odourless and tasteless
- Suitable for medical and FDA-compliant grades
- Biocompatible material options available
These properties make LSR ideal for demanding environments where conventional thermoplastic elastomers may not perform reliably.
UK-Based Liquid Silicone Rubber Injection Moulding
Manufacturing LSR components in-house in the UK provides significant advantages:
- Reduced lead times
- Elimination of overseas shipping costs
- Greater supply chain reliability
- Direct collaboration with our engineering team
- Strict quality control standards
Our domestic production capability ensures consistent quality while giving customers greater visibility and confidence throughout the manufacturing process.