Custom Silicone Components
LSR Overmolding Manufacturer for Custom Silicone Components
We manufacture custom LSR overmolded parts for OEMs and engineering teams that need silicone bonded to plastic or metal substrates for sealing, protection, grip, insulation, or functional performance.
LSRParts supports your project from DFM review, material selection, substrate bonding strategy, mold design, sampling, validation, mass production, secondary operations, inspection, assembly, and packaging.
If you have a drawing, 3D model, substrate design, application requirement, or production forecast, we can help you move from concept to production-ready LSR overmolded components.
Custom LSR Overmolding Built Around Your Part Design
LSR overmolding is used when liquid silicone rubber must be molded directly onto another component, commonly plastic or metal, to create an integrated part with sealing, cushioning, waterproofing, ergonomic, or protective functions.
We do not focus on standard off-the-shelf silicone products. We manufacture custom overmolded silicone components based on your drawing, substrate, bonding requirements, tolerance targets, and production needs.
LSR Overmolding Capabilities
| Process | Liquid Silicone Rubber Overmolding |
| Maximum Part Envelope | 300 x 200 x 100 mm |
| LSR Hardness | 10-80 Shore A |
| Mold Manufacturing Tolerance | +/- 0.01 mm |
| Typical Part Tolerance | +/- 0.05 mm |
| Critical Tolerance | Down to +/- 0.02 mm, application dependent |
| Mold Cavities | Single-cavity / Multi-cavity |
| Mold Life | 3-5 million shots depending on tooling and application |
| Plastic Substrates | PC, PA, PBT, PPSU, PPA, PEI, and others |
| Metal Substrates | Aluminum, stainless steel, brass, copper |
| Bonding Strategy | Chemical bonding / mechanical bonding / hybrid design |
| Insert Molding | Supported |
| Tooling Type | Prototype tooling / production tooling |
| Production Scale | Prototype to high-volume mass production |
| Color | Custom color / Pantone matching |
| Surface | Matte, polished, textured, custom finish |
| Secondary Operations | Post-curing, trimming, printing, laser marking, bonding, assembly, inspection |
What We Need for an LSR Overmolding RFQ
To quote accurately, we recommend sending as much of the following information as possible:
- 2D drawing and 3D CAD file
- Substrate material and supplier information if available
- Required silicone hardness
- Annual volume and expected order quantity
- Target application and operating environment
- Bonding requirement: chemical, mechanical, or both
- Tolerance requirements and critical dimensions
- Color or surface finish requirements
- Regulatory or material requirements (medical, food-grade, flame-retardant, high-temperature)
- Current pain points if replacing an existing supplier or part
If your design is not finalized, we can still review early-stage geometry and provide DFM feedback before tooling.
LSR Overmolding for Plastic and Metal Substrates
We support both plastic and metal insert overmolding. Our engineering review focuses on how the silicone will flow, bond, seal, and release from the mold while maintaining dimensional consistency in production.
Plastic Overmolding
Typical plastic substrates include:
Plastic overmolding is commonly used for connectors, sensor housings, medical device components, electronics housings, grips, and sealed assemblies.
Metal Overmolding
Typical metal substrates include:
Metal overmolding is used where the component requires structural strength, conductivity, heat resistance, chemical resistance, or precise mechanical positioning combined with a silicone sealing or protective function.
Bonding Strategy: Chemical, Mechanical, or Both
A successful LSR overmolded component depends on more than mold construction. Bonding must be reviewed early.
We evaluate:
- Substrate material compatibility
- Surface treatment requirements
- Primer or adhesive system when needed
- Mechanical retention features
- Undercuts, holes, grooves, ribs, locking geometry
- Silicone flow path and venting
- Thermal exposure during molding
- Operating temperature and chemical exposure
- Peel, pull, compression, sealing requirements
For demanding applications, we may recommend combining chemical bonding with mechanical interlock features to improve reliability.
DFM Review Before Tooling
A reliable overmolded silicone part starts before the mold is built.
Our engineering team reviews part geometry, substrate stability, wall thickness, sealing features, draft, undercuts, flash requirements, silicone hardness, shrinkage, bonding areas, tolerance requirements, and expected production volume before tooling begins.
This helps identify manufacturing risks earlier and gives your team a clearer path from prototype validation to repeatable production.
Our typical workflow
Tooling for Prototype and Production LSR Overmolding
We build molds based on the stage and production requirements of your project.
| DFM Review | Supported |
| CAD | SolidWorks / CAD |
| Mold Flow Review | Supported |
| CNC | 3-axis / 5-axis CNC |
| EDM | Sinker EDM / Wire EDM |
| Rapid Tooling | Aluminum tooling |
| Rapid Tool Life | Approx. 100-10,000 cycles |
| Production Tooling | Hardened steel tooling |
| Common Mold Steel | P20 / NAK80 / H13 / S136 / 420 |
| Stainless Tooling | 316 / 420 where applicable |
| Aluminum Tooling | 6061 / 7075 |
| Tool Surface Finish | Ra 0.8 um or better where required |
| Prototype Tool Lead Time | Benchmark approx. 10-12 days |
| Production Tool Lead Time | Benchmark approx. 3-6 weeks |
| Sampling | T0 / T1 / validation |
| Multi-Cavity Tooling | Yes |
| High-Volume Tooling | Yes |
For annual demand above 100,000 pieces, we can help evaluate cavity count, cycle time, tool steel selection, automation options, inspection requirements, and cost-per-part targets.
Materials for LSR Overmolding
We help select silicone material based on application, environment, compliance requirements, and functional performance.
General Purpose LSR
Industrial / electronics
Medical Grade LSR
Medical devices
Food Grade LSR
Food / beverage / baby products
Platinum-Cured Silicone
Medical / food contact
Optical LSR
Optical / lighting
Fluorosilicone
Automotive / fuel / chemical exposure
High-Temperature Silicone
Automotive / industrial
Low-Temperature Silicone
Outdoor / automotive
Electrically Conductive Silicone
Electronics / EMI
Thermally Conductive Silicone
Thermal management
Flame-Retardant Silicone
Electrical / automotive
Custom Compounds
Application-specific requirements
Secondary Operations for Overmolded Silicone Parts
We can support secondary processing after molding when your part requires additional finishing, identification, assembly, or functional verification.
Industries We Serve
We work with OEMs, Tier suppliers, product developers, and engineering teams that need custom silicone overmolding for production applications.
Automotive & EV
Common parts include:
- Connector seals
- Wire seals
- Battery seals
- Sensor seals
- Overmolded protective components
- High-temperature silicone sealing parts
Medical & Healthcare
Common parts include:
- Device seals
- Septa
- Plunger tips
- Valves
- Diaphragms
- Tubing interfaces
- Overmolded medical device components
Pumps, Valves & Fluid Control
Common parts include:
- Diaphragms
- Membranes
- Check valves
- Sealing components
- Fluid-contact silicone parts
Electronics & Sensors
Common parts include:
- Waterproof seals
- Housing seals
- Keypads
- Sensor seals
- Overmolded electronic protection parts
- EMI or thermal silicone components
Food, Beverage & Baby Care
Common parts include:
- Bottle valves
- Breast pump parts
- Food-grade seals
- Silicone tubing interfaces
- Soft-touch overmolded components
Why OEMs Choose LSRParts for LSR Overmolding
We are best suited for projects that require custom tooling, engineering review, precision molding, and repeat production.
Our ideal projects usually include:
- Custom 2D drawings or 3D files
- New tooling requirements
- Annual demand above 100,000 pieces
- Functional or precision requirements
- Prototype-to-mass-production programs
- Need for DFM and material selection support
- Long-term repeat production
We focus on high-value custom silicone components rather than low-volume commodity rubber products.
Quality and Production Control
For LSR overmolding, dimensional stability and bonding consistency are critical. We plan inspection around the function of the part, not only the drawing dimensions.
Depending on the project, we can inspect:
- Critical dimensions
- Flash conditions
- Bonding area integrity
- Surface defects
- Color consistency
- Silicone coverage
- Insert position
- Seal geometry
- Functional performance
- Assembly fit
- Packaging requirements
For validation projects, we support T0/T1 sampling and production approval before mass production.
LSR Overmolding RFQ Checklist
Before sending your RFQ, the following checklist can help accelerate review:
- Do you have 2D and 3D files?
- What is the substrate material?
- Will the substrate be supplied by you or manufactured by us?
- What silicone hardness is required?
- Does the part require chemical bonding?
- Are mechanical locking features already included?
- What are the critical tolerances?
- What is the annual production volume?
- What is the expected project stage: prototype, validation, or mass production?
- Are there medical, food, automotive, flame-retardant, or other material requirements?
- Are secondary operations required?
If some details are missing, we can help review the application and recommend next steps.
Request a Quote for Custom LSR Overmolding
Send us your drawing, 3D file, substrate information, material requirements, and estimated annual volume. Our team will review the design for manufacturability, bonding feasibility, tooling approach, and production cost factors.
We support OEMs and engineering teams from early DFM review through production tooling and mass manufacturing.
Contact LSRParts for your LSR overmolding RFQ.