Liquid Silicone Rubber Injection Molding for Custom LSR Parts
Xiongfeng provides liquid silicone rubber injection molding services for precision, flexible, heat-resistant, and chemically stable silicone components. Our capabilities cover DFM review, LSR mold tooling, material selection, prototype validation, low-volume production, repeat molding, insert molding, inspection, assembly, and packaging.
- Platinum-cured two-component LSR
- Precision flash-controlled tooling
- Insert molding and overmolding
- Prototype to repeat production
From LSR Part Design to Stable Production
Liquid silicone rubber injection molding uses a meter-mixed, two-component silicone material that is injected into a heated mold and cured into a flexible elastomeric part. The process is suitable for precision seals, membranes, medical components, electronic protection, connectors, valves, gaskets, and other demanding parts.
Successful LSR molding requires careful control of material dosing, mold temperature, venting, parting-line sealing, flash, gate design, shrinkage, demolding, and post-processing requirements.
- Soft, flexible, and resilient components
- High and low temperature performance
- Electrical insulation and sealing
- Fine details and thin flexible features
- Biocompatible or food-contact grades by request
- Insert molding with metal or plastic components
Why Manufacturers Choose Liquid Silicone Rubber
LSR combines elasticity, thermal stability, chemical resistance, electrical insulation, and long-term flexibility for demanding applications.
Silicone Molding Solutions for Different Product Requirements
The correct LSR molding strategy depends on part geometry, hardness, quantity, flash requirements, sealing performance, color, certification needs, inserts, and final application.
LSR Design and DFM Review
Engineering review before tooling to identify features that may affect filling, venting, flash, demolding, sealing, and tolerance.
- Wall thickness and flexible geometry
- Parting line and gate planning
- Sealing surfaces and flash limits
Custom LSR Mold Tooling
Precision tooling designed for low-viscosity silicone flow, controlled venting, accurate shut-offs, and repeatable demolding.
- Cold-runner tooling concepts
- Single-cavity and multi-cavity options
- Flash-controlled parting surfaces
Prototype and Pilot LSR Molding
Molded samples and early production quantities for design validation, fit, sealing tests, certification, and market launch.
- Production-intent silicone samples
- Functional and sealing validation
- Pilot and bridge quantities
Production LSR Molding
Repeat manufacturing with controlled material dosing, molding parameters, inspection, trimming, assembly, and packaging.
- Repeat production programs
- Multi-cavity manufacturing options
- Batch inspection and packaging control
LSR Insert Molding
Silicone is molded around metal, plastic, electronic, or structural inserts to create integrated sealing and functional components.
- Metal and plastic inserts
- Electrical and connector components
- Reduced secondary assembly
LSR Overmolding
Liquid silicone can be molded over a rigid substrate to add sealing, grip, cushioning, insulation, or environmental protection.
- Soft-touch and sealing features
- Rigid-substrate integration
- Multi-material component designs
Custom Liquid Silicone Rubber Components
We support silicone parts with different hardness levels, geometries, colors, sealing requirements, insert structures, and production quantities.
Seals and Gaskets
Custom sealing rings, gaskets, protective seals, valve seals, and fluid-control components.
Membranes and Diaphragms
Thin flexible membranes, diaphragms, valve elements, and pressure-responsive components.
Medical and Healthcare Parts
Device seals, tubing-related components, masks, valves, and application-specific healthcare components.
Electronic Protection Parts
Connector seals, keypads, boots, insulating covers, cable seals, and environmental protection components.
Silicone Grades for Different Functional Requirements
Material selection should consider hardness, temperature, compression set, tear strength, transparency, color, electrical properties, sterilization, food contact, and biocompatibility.
General-Purpose LSR
Suitable for common seals, flexible components, protective parts, and general industrial applications.
Medical-Grade LSR
Used for healthcare and medical-device applications where documented material compliance may be required.
Food-Contact LSR
Material options for food-contact, kitchen, appliance, and beverage-related applications, subject to project requirements.
High-Temperature LSR
Suitable for components exposed to elevated operating temperatures, thermal cycling, or sterilization processes.
Flame-Retardant LSR
Special grades for electrical, transportation, and industrial applications requiring flame-performance consideration.
Self-Bonding LSR
Selected grades can improve bonding to compatible plastic or metal substrates in overmolding applications.
Optically Clear LSR
Transparent silicone for lenses, light guides, protective optical components, and lighting applications.
Colored LSR
Custom color options for identification, branding, appearance, safety coding, and product differentiation.
Liquid Silicone Rubber Molding Design Considerations
LSR part design must account for low material viscosity, flexible geometry, flash control, shrinkage, venting, demolding, and sealing performance.
| Design Element | LSR Manufacturing Consideration | Buyer Guidance |
|---|---|---|
| Wall Thickness | Consistent sections support balanced filling and predictable curing | Avoid unnecessary abrupt thickness changes |
| Parting Line | Low-viscosity LSR can enter extremely small gaps and create flash | Place parting lines away from critical sealing surfaces |
| Draft and Demolding | Flexible parts may demold differently from rigid thermoplastics | Review draft, undercuts, and automatic removal strategy |
| Venting | Controlled venting helps avoid trapped air, burns, and incomplete filling | Identify thin sections and end-of-fill locations |
| Sealing Surfaces | Flash, dimensional variation, and surface defects can affect sealing | Clearly mark critical sealing dimensions and defect limits |
| Insert Bonding | Bonding depends on substrate material, preparation, LSR grade, and geometry | Provide substrate specifications and pull-off requirements |
LSR Components for Demanding Applications
Liquid silicone rubber is used where flexibility, sealing, temperature resistance, insulation, cleanliness, and long-term stability are important.
Medical Devices
Automotive
Electronics
Home Appliances
Industrial Equipment
Consumer Products
From CAD Review to Finished Silicone Parts
A structured workflow helps control mold design, material dosing, curing, flash, dimensions, appearance, inspection, and delivery.
Project and DFM Review
Review CAD files, LSR grade, hardness, quantity, tolerances, sealing, color, inserts, compliance, and delivery requirements.
LSR Mold Design and Tooling
Develop mold structure, gates, venting, cold-runner concept, parting-line sealing, ejection, and insert positioning.
Mold Trial and Sample Validation
Produce trial parts and review dimensions, flash, filling, cure, appearance, demolding, sealing, and function.
Production and Delivery
Move approved parts into controlled molding, trimming, post-curing if required, inspection, assembly, packaging, and shipment.
Why Choose Xiongfeng for LSR Injection Molding?
We coordinate LSR part design, material selection, tooling, molding, insert integration, inspection, trimming, assembly, and packaging.
LSR-Specific DFM Support
Review of flexible geometry, sealing surfaces, gates, venting, flash, demolding, shrinkage, and insert bonding.
Precision Mold Tooling
Tooling designed for low-viscosity material flow, accurate shut-off surfaces, controlled venting, and repeatable production.
Flexible Production Quantities
Support for prototypes, functional samples, pilot quantities, bridge production, and repeat manufacturing.
Multiple LSR Grades
Support for general-purpose, medical, food-contact, transparent, colored, high-temperature, and specialty silicone grades.
Insert and Overmolding Support
Integration of metal, plastic, electrical, and structural substrates with molded silicone sealing or protection.
Quality and Functional Inspection
Dimensional, visual, sealing, bonding, fit, assembly, and functional checks according to project requirements.
Inspection Throughout the LSR Molding Process
LSR quality planning begins with material, tooling, sealing surfaces, flash limits, critical dimensions, appearance, hardness, bonding, and functional requirements.
Finishing, Assembly, and Post-Processing for LSR Parts
Additional operations can support cleanliness, appearance, identification, bonding, assembly, packaging, and final application requirements.
As Molded
Standard molded finish based on tool surface and LSR grade.
Flash Trimming
Removal of permitted edge flash according to product requirements.
Post-Curing
Additional thermal processing when required by material or application.
Surface Treatment
Selected treatments for bonding, printing, coating, or assembly.
Printing and Marking
Product identification, graphics, symbols, or traceability marks.
Insert Assembly
Installation of compatible metal or plastic components where needed.
Subassembly
Assembly of silicone components with housings, connectors, or hardware.
Custom Packaging
Clean, separated, protected, or application-specific packaging.
Liquid Silicone Rubber Injection Molding FAQs
Learn more about LSR materials, mold design, hardness, flash, quantities, inserts, overmolding, compliance, and post-curing.
What is liquid silicone rubber injection molding?
LSR injection molding is a process in which two liquid silicone components are accurately metered and mixed, injected into a heated mold, and cured into a flexible elastomeric part.
What is the difference between LSR and thermoplastic injection molding?
Thermoplastics are melted and cooled inside the mold. LSR is a two-component thermosetting silicone that is mixed, injected into a heated mold, and chemically cured. Tooling, temperature, material handling, venting, and flash control are therefore different.
What hardness levels are available for LSR?
LSR is available in multiple hardness ranges. The appropriate Shore A hardness depends on flexibility, sealing pressure, compression, tear strength, handling, and functional requirements.
Can LSR be molded around metal or plastic inserts?
Yes. LSR insert molding and overmolding can integrate metal, plastic, electronic, or structural substrates. Bonding depends on the substrate, geometry, surface preparation, LSR grade, and application requirements.
Can you provide medical-grade or food-contact LSR?
Material grades with relevant supplier documentation can be discussed according to the specific application, market, and compliance requirements. Required standards should be confirmed before quotation.
How is flash controlled in LSR molding?
Flash control depends on mold accuracy, shut-off surfaces, parting-line design, venting, clamping, material flow, and molding parameters. Critical flash limits should be marked on the drawing.
Does LSR require post-curing?
Post-curing requirements depend on the silicone grade, application, performance target, odor or volatile limits, and compliance requirements. It should be defined during material and process planning.
What files are needed for an LSR molding quotation?
- 3D CAD files such as STEP, STP, IGES, or X_T
- 2D drawings with critical dimensions and flash limits
- Hardness, color, and silicone-grade requirements
- Initial and annual quantities
- Insert, bonding, sealing, and assembly requirements
- Compliance and target delivery requirements
Silicone Molding Guides and Engineering Insights
Explore practical information about LSR design, material selection, tooling, flash control, insert molding, and quality inspection.
Design for Liquid Silicone Rubber Molding
Learn how wall thickness, parting lines, gates, venting, demolding, sealing surfaces, and flash affect LSR components.
Read Article →
Liquid Silicone Rubber Material Selection Guide
Compare hardness, temperature, compression set, transparency, color, electrical performance, and compliance requirements.
Read Article →
Common LSR Molding Defects and Prevention
Understand flash, short shots, trapped air, incomplete cure, contamination, bonding problems, and dimensional variation.
Read Article →Start Your LSR Injection Molding Project
Upload your CAD files and drawings. Our team will review the LSR grade, hardness, quantity, geometry, sealing surfaces, flash limits, inserts, compliance needs, tooling, inspection, and delivery requirements.
- LSR-specific DFM and tooling review
- Material, hardness, and color recommendations
- Prototype and production molding quotations
- Insert molding, inspection, assembly, and packaging support
Request an LSR Molding Quote
Complete the form and upload your project files. Our team will review the application and respond with manufacturing feedback.