LSR Injection Molding Guide | Custom Liquid Silicone Rubber Parts Manufacturer
LSR Injection Molding Guide | Custom Liquid Silicone Rubber Parts Manufacturer
ZetarMold provides custom LSR Injection Molding services for medical, automotive, electronics, and industrial applications. Learn about LSR materials, mold design, process, and silicone part manufacturing.
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Resources for The Complete Guide to LSR Injection Molding
Resources for The Complete Guide to LSR Injection Molding
Resources for The Complete Guide to LSR Injection Molding
Two-Component System

Why LSR is Widely Used?
LSR is supplied as two separate components that are automatically mixed at a precise 1:1 ratio before injection into a heated mold.
- Component A: Silicone polymer and platinum catalyst
- Component B: Cross-linking agent and additives
Unlike thermoplastic materials, LSR undergoes a chemical cross-linking reaction inside the heated mold, permanently transforming from liquid to solid.
- This unique curing process enables superior performance characteristics and long-term stability.
Two-Component System
Two-Component System
Thermoset Elastomer
Thermoset Elastomer
- Excellent temperature resistance
- Good chemical resistance
- Biocompatibility for medical apps
- High elasticity and flexibility
- Excellent sealing performance
- Long-term durability
- Excellent temperature resistance
- Good chemical resistance
- Biocompatibility for medical apps


Balanced mechanical performance and cost efficiency
- Consumer products
- Silicone covers
- Sealing components
High purity and biocompatibility for healthcare
- Medical seals
- Respiratory components
- Drug delivery devices
Safe for direct food contact
- Kitchen products
- Baby feeding products
- Food container seals

General-Purpose LSR


Medical Grade LSR

Food Grade LSR
Continuous exposure to elevated temperatures
- Automotive components
- Industrial seals
- High-temp gaskets
Excellent transparency and light transmission
- Optical lenses
- LED components
- Optical sensors
Improved fire resistance for safety
- Electrical components
- Electronic protection
- Industrial equipment

High-Temperature LSR


Optical Grade LSR


Flame-Retardant LSR




Temperature Resistance
One of the biggest advantages of LSR is its ability to maintain performance across a wide temperature range.
Compared with many thermoplastic elastomers, LSR can withstand:
- High-temperature environments
- Repeated thermal cycling
- Outdoor exposure
This makes it suitable for automotive, medical, and industrial applications.

Flexibility and Elastic Recovery
LSR has excellent elasticity, allowing molded parts to repeatedly deform and return to their original shape.
This property is especially important for:
- Seals
- Valves
- Membranes
- Flexible buttons
- Wearable devices



Chemical and Environmental Resistance
LSR provides excellent resistance against:
- Moisture
- UV exposure
- Ozone
- Many chemicals
- Cleaning agents
This makes it suitable for products used in demanding environments.
Biocompatibility
Certain LSR grades are suitable for medical applications due to their:
- Low toxicity
- Skin compatibility
- Sterilization resistance
- Long-term stability
For medical projects, material selection should always consider regulatory requirements and application conditions.

Step 1: Material Mixing
Why choose injection molding for LSR parts?
Step 1: Material Mixing
The two LSR components are stored separately and automatically mixed at a precise 1:1 ratio.
Step 2: Injection
The mixed liquid silicone material is injected into a heated mold cavity under controlled pressure.
Step 3: Curing
Inside the mold, heat activates the platinum curing reaction, converting the liquid silicone into a solid elastomer.
Step 4: Demolding
After curing, the finished silicone part is removed from the mold and prepared for inspection or secondary operations.
Step 1: Material Mixing
Step 2: Injection
Step 3: Curing
Step 4: Demolding
Why choose injection molding for LSR parts?
LSR injection molding provides several manufacturing advantages:
- High production efficiency
- Consistent part quality
- Ability to produce complex geometries
- Reduced material waste
- Automated production capability
- Suitable for cleanroom manufacturing
For industries requiring thousands or millions of identical silicone parts, LSR injection molding provides a reliable and scalable manufacturing solution.




Medical and Healthcare
- Medical seals and gaskets
- Respiratory device components
- Surgical instrument components
- Drug delivery system parts
- Wearable medical device components

Automotive
- Engine seals
- Electrical connectors
- Sensor seals
- Valve covers
- Waterproofing components



Consumer Electronics
- Waterproof seals
- Protective covers
- Keypads
- Wearable device components
- Earphone accessories

Baby and Consumer Products
- Baby bottle nipples
- Pacifiers
- Kitchen seals
- Silicone containers
- Household accessories


Maintain Uniform Wall Thickness
Maintain Uniform Wall Thickness
Consider Draft Angles
Avoid Sharp Corners
Design for Undercuts Carefully
Optimize Gate Location
Optimize Gate Location
Use Proper Venting
Design for Automatic Demolding
Surface Finish Requirements
Maintain Uniform Wall Thickness
Consider Draft Angles
Avoid Sharp Corners
Design for Undercuts Carefully
Optimize Gate Location
Use Proper Venting
Design for Automatic Demolding
Surface Finish Requirements
LSR Injection Molding: Complete Guide to Liquid Silicone Rubber Manufacturing
LSR Injection Molding: Complete Guide to Liquid Silicone Rubber Manufacturing
Explore our complete guide to LSR Injection Molding, including Liquid Silicone Rubber materials, design guidelines, molding process, applications, LSR overmolding, and custom silicone part manufacturing solutions.
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Resources for The Complete Guide to LSR Injection Molding
Resources for The Complete Guide to LSR Injection Molding
Resources for The Complete Guide to LSR Injection Molding




Advantages of LSR Overmolding

Advantages of LSR Overmolding
- Improved waterproof performance
- Reduced assembly steps
- Better product durability
- Soft-touch surface
- Enhanced user experience
- Improved sealing reliability
Choose TPE When You Need:
- Medical devices
- Wearable electronics
- Automotive sensors
- Consumer electronics
- Industrial equipment
Advantages of LSR Overmolding
Choose TPE When You Need:
Excellent Temperature Resistance
LSR can typically withstand high-temperature environments, low-temperature conditions, and repeated thermal cycling, making it ideal for automotive, industrial, and electronic applications.
LSR provides excellent elastic recovery, allowing parts to repeatedly compress, stretch, and return to original shape. Essential for seals, valves, membranes, and soft-touch components.
LSR is resistant to moisture, UV exposure, ozone, many chemicals, and cleaning agents, enabling long-term outdoor and industrial applications.
Because of its flexibility and compression set resistance, LSR is widely used for sealing applications including O-rings, gaskets, waterproof seals, and valve components.
LSR injection molding can produce thin-wall parts, complex shapes, micro features, and multi-cavity components with consistent quality for large-volume projects.
Medical-grade LSR provides biocompatibility, sterilization resistance, long-term stability, and skin-contact compatibility, widely used in healthcare products and medical devices.
LSR injection molding is ideal for automated manufacturing, reducing labor costs while providing stable cycle times, high repeatability, and consistent quality for high-volume silicone parts.
Excellent Temperature Resistance
Excellent Temperature Resistance
High Flexibility and Elasticity
High Flexibility and Elasticity
Excellent Chemical and Environmental Resistance
Excellent Chemical and Environmental Resistance
Superior Sealing Performance
Superior Sealing Performance
High Precision and Complex Geometry
High Precision and Complex Geometry
Suitable for Medical Applications
Suitable for Medical Applications
Automation and Mass Production Capability
Automation and Mass Production Capability
Higher Tooling Cost
- More precise machining required
- Better mold sealing needed
- Advanced runner systems
- Additional venting design
- Cold runner design expertise
- Flash prevention challenges
- Venting optimization
- Material flow control
- Premium material pricing
- Longer product lifespan
- Better temperature resistance
- Improved performance justifies cost
- Thermoset material structure
- Scrap recycling difficulty
- Material waste management
- Careful planning required
Higher Tooling Cost
Higher Tooling Cost
More Complex Mold Design
More Complex Mold Design
Higher Material Cost
Higher Material Cost
Limited Recycling Options
Limited Recycling Options
Choose LSR When You Need:
Choose LSR When You Need:
There is no universal answer because the best material depends on application requirements. A professional material evaluation should consider product requirements, production volume, environmental conditions, and regulatory standards before selecting the final material. LSR excels in demanding applications requiring extreme performance, while TPE offers cost-effectiveness for consumer products where extreme performance is not required.
Choose LSR When You Need:
- High temperature resistance
- Medical-grade performance
- Long-term durability
- Excellent sealing
- Extreme environmental resistance

Choose TPE When You Need:
- Lower material cost
- Easier recycling
- Thermoplastic processing
- Soft-touch consumer products
- Faster development cycles

Choose LSR When You Need:
Choose TPE When You Need:
Choose LSR When You Need:
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