Liquid Silicone Rubber Injection Molding Solutions
We provide end-to-end silicone injection molding solutions focused on optical-grade elastomer components. Our team specializes in lsr molding and liquid silicone injection molding, delivering a complete workflow from product concept and DFM, design validation, and rapid prototyping to precision tooling and scalable production. We support both standalone LSR parts and integrated builds through a liquid silicone rubber injection molding service model aligned with your drawings, tolerances, and test requirements.
Advantages of LSR Injection Molding
LSR is highly resistant to extreme temperatures, chemicals, and UV exposure, making it suitable for long-life sealing and optical applications.
LSR can be molded into complex geometries, including thin-wall features, micro details, and multi-component structures, offering more design flexibility than many elastomers.
LSR injection molding supports insert molding and overmolding with metals, plastics, ceramics, and other substrates to meet specialized functional and assembly requirements.
Because LSR is non-toxic and hypoallergenic, it is widely used for hygienic and skin-contact applications, including seals, gaskets, and tubing components.
Compared with many alternative processes, LSR injection molding enables faster cycle times and efficient automation for higher-volume runs.
Our ISO-certified Class 8 cleanroom helps reduce contamination risk and supports consistent production of liquid silicone rubber parts and high-clarity components.
Applications of LSR Injection Molding
LSR injection molding delivers high precision for micro and thin-wall parts, with strong biocompatibility potential and optical clarity. Combined with overmolding, it is used across automotive, medical, electronics, and optical programs. Typical outputs include liquid silicone rubber products such as sealing elements, protective covers, and optical components like injection molded optics and injection molded lenses. For optical use cases, we also support optical LSR material options based on transmittance, haze, and yellowing resistance targets.
Custom LSR Injection Molding Capabilities
| Feature | Tip |
|---|---|
| Industries Served |
• Medical devices
• Automotive seals & connectors • Consumer electronics • Food-grade & baby products. |
| Molding Process |
• Cold runner LSR molding
• Two-shot / multi-color LSR molding • LSR overmolding plastic/metal |
| Material Capability |
We support leading global and domestic LSR material brands and offer customized formulations for hardness, color, and grade.
• Hardness range: Shore A 15A–80A • Clear/translucent LSR (including optical grade), light transmittance ≥ 93 • Medical-grade LSR materials offer reliable biocompatibility, meeting requirements |
| Product Size Capability |
• Min micro part size: 1–3 mm
• Minimum wall thickness: 0.20–0.30 mm |
| Overmolding Capability |
• Overmolding plastics: PC, PA, PP, PBT, etc.
• Overmolding metals: aluminum, stainless steel, etc. |
| Secondary Processing |
• Deburring (cryogenic/manual)
• Silk printing, laser engraving, coating • Post-curing (medical/food grade requirements) • Plasma / Corona treatment for enhanced bonding |
| Testing Capability |
• Hardness, tensile & tear strength testing
• Optical transmittance & haze testing • CMM & projector measurement • ROHS and REACH material testing capability |
| Mold Capability |
In-house mold workshop with high-precision mold machining equipment
• Mold tolerance: ±0.005 mm |
What is LSR Injection Molding
Injection molding of liquid silicone rubber (LSR) is a highly efficient and precise process used in medical, automotive, electronics, and consumer industries. It is also commonly referred to as liquid silicone rubber injection molding or liquid injection molding in production environments.
In the molding process, two liquid silicone components (Part A and Part B) are metered, mixed, and injected under pressure into a heated mold. The material cures rapidly inside the mold, forming the intended shape with strong dimensional stability and repeatable part quality.
LSR Injection Molding Capabilities
Single-shot LSR
Liquid silicone is injected into a mold and cured in one step by heating, requiring no secondary processing.
Multi-shot LSR
In two shot molding, the LSR and thermoplastic parts are both molded and combined during the same molding cycle.
Overmolding
By bonding silicone to metals, plastics, and other substrates, structural integrity and sealing performance are enhanced.
Silicone Material Customization
The silicone raw material system strongly influences final part performance and appearance. Different material families and brands vary in heat resistance, low-temperature flexibility, UV stability, oxidation resistance, and long-term aging behavior. We maintain supply partnerships with leading brands and can recommend appropriate material grades from liquid silicone manufacturers based on your functional requirements and production conditions.
We offer material options aligned with safety and compliance needs, including FDA, LFGB, and REACH. For projects requiring higher cleanliness and traceability, we can discuss medical-grade liquid silicone rubber options and define the documentation scope based on your intended use.
1. Optical-Grade Silicone
Physical properties for optical-grade LSR
1. Extremely high light transmittance (≈93–94%), low haze (<1%)
2. Excellent UV and blue-light stability with strong anti-yellowing performance
3. UL certification support, including UL 94 flame retardancy rating options
2. Industrial Electronic
Physical properties for electronics and power modules
1. Waterproof (IP67–IP69K), insulated, and chemically resistant LSR silicone
2. High-insulation and thermal options with strong bonding performance and UL-aligned safety requirements
3. Soft-touch, ergonomic, skin-safe LSR with customizable hardness and colors to support product differentiation
3. Medical-Grade Silicone
ISO 10993-aligned silicone options with high purity, long-term stability, and established safety evaluation pathways. These grades are commonly used for medical-grade silicone parts and selected medical device component applications when the project scope, documentation, and customer requirements are clearly defined.
Post-processing for Liquid Silicone Rubber Products
Cryogenic deflashing
Mechanical deflashing
Manual trimming
Plasma deburring
Plasma treatment
UV modification treatment
Spraying treatment
Ultrasonic metal welding
Parts assembly
Overmolded components
Plastic + fabric parts
Ultrasonic cleaning
Sand blasting
Post-curing
Typical: 200°C for 2–4 hrs
Sterilization (Medical Applications)
2. Gamma irradiation
3. Ethylene oxide sterilization
Quality Control & Testing
Dimensional inspection
Tensile / Tear strength testing
Automatic button load tester
Button life tester
XRF spectroscopy testing machine
Color matching light box tester
Custom Liquid Silicone Rubber Product Workflow
The following is our product customization process. At Lanxin, turning your ideas into real, high-performance products is what we do best. Partner with us for a smooth, efficient and innovative journey — from concept to completion. Want to see how we bring your ideas to life? Let’s get started.
FAQs
Read the Frequently Asked Questions for more information.
There’s no answer here for you? Please contact us and we will respond within 24 hours.
What industries use LSR injection molding?
LSR injection molding is used in industries like automotive, healthcare, consumer electronics, food and beverage, and industrial manufacturing.
What types of products can be made using LSR injection molding?
What is the difference between RTV and LSR?
What is the pressure for LSR injection?
What is the curing time for LSR injection molding?
What should I send you to get an accurate quote for an LSR molded part?
Send a 3D CAD file (STEP is ideal) plus a 2D drawing that calls out critical dimensions, tolerances, and datums. Include the LSR grade or target properties (hardness, color, translucency, biocompatibility needs), expected annual volume and release schedule, and your quality requirements (inspection level, PPAP or equivalent). Also share application details like mating parts, sealing surfaces, operating temperature range, chemicals the part will see, and any assembly or post-cure requirements.
What tolerance range can we realistically hold with LSR injection molding?
For most LSR parts, a practical baseline is around plus or minus 0.05 to 0.10 mm on small, well-supported dimensions, and wider on larger spans or soft, thin features. Very tight tolerances are possible, but only on specific features with robust tooling design, stable processing, and good part restraint in the mold. The honest answer is: define which dimensions are truly critical, and we’ll tolerate those intentionally while keeping the rest more forgiving to protect yield and cost.
How is LSR tooling different from a standard plastic injection mold?
LSR molds are built around liquid dosing, mixing, and a cold-runner feed system, with the mold itself heated to cure the rubber. They need excellent sealing to prevent flash, high-quality venting for trapped air, and careful parting line strategy because LSR will find any gap. You’ll also see different gating, temperature control, and often more emphasis on demolding design because parts are elastic and can distort if ejected poorly.
What should we watch for in LSR injection mold design?
Design for controlled flash, clean venting, and consistent fill. That means tight shutoffs, smart parting lines away from cosmetic or sealing areas, and vent locations that actually let air escape without leaving marks. Plan gating to avoid knit lines on functional surfaces, and make sure ejection and handling won’t stretch critical features. Also account for shrink, compression set targets if it’s a seal, and any post-cure dimensional change if post-curing is required.
What is the thermal stability window for the LSR process?
Start with your industry: medical, food contact, baby products, electronics, automotive, and so on all drive different requirements. Common expectations include material traceability, lot control, defined inspection plans, and process validation. Depending on the application, you may need ISO 9001 or ISO 13485, PPAP-style documentation, biocompatibility testing (like ISO 10993), food-contact compliance (FDA or EU frameworks), and chemical or flame requirements. The key is to align testing and documentation to the end-use and the markets you’ll ship into.
What types of cold runner systems are used in LSR injection molding?
In production terms, you’re balancing a cold feed system with a hot cure tool. The material is typically kept cool in the metering and cold runner to avoid premature curing, while the cavities are heated high enough to cure fast and consistently. The usable window depends heavily on the exact LSR grade, part thickness, and cycle time targets, so the best way to lock it in is to confirm the supplier’s recommended temperatures and then validate it during trials with cure studies and dimensional checks.
Applications in different fields
In-house Mold Shop for Quick Delivery
GF AgieCharmillers EDM,
Japan‘s Sodick EDM
silicone tooling making
Automated production process and brand cooperation experience
ISO 13485:2016
IATF 16949
LSR Injection Molding
Cost-effective price, large quantity delivery
Insert molding
Nearly 100 molding equipment
Silicone Compression Molding
A Variety of Materials to Meet Different Application
Velcro Series
Double-Sided Adhesive Tape
Silicone Die Cutting
Silicone raw materials are used to cover different materials.
Silicone + Plastic
Silicone + Ceramics
Overmolding & Insert Molding
Offer a range of secondary processing services.
Printing
Spray painting
Packaging and Shipping
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