Custom Precision Silicone Masking & Sealing Solutions
Silicone Caps & Plugs
LSRParts is a premier manufacturer of custom silicone caps and plugs, engineered for demanding industrial, automotive, medical, and electronic applications. We specialize in precision liquid silicone rubber (LSR) molding and compression molding to deliver high-performance masking, sealing, and protective components.
Rather than supplying standard off-the-shelf rubber products, we focus entirely on custom silicone caps and plugs built around your specific 3D drawings, application environments, and performance requirements. From early Design for Manufacturability (DFM) review and material selection through mold design, sampling, and high-volume mass production, LSRParts provides a complete manufacturing solution for OEMs and product developers.
Precision Silicone Caps & Plugs Built for Production
Silicone caps and plugs are critical components used for masking during surface finishing processes (like powder coating, E-coating, plating, and anodizing), environmental sealing, and fluid control. They must withstand extreme temperatures, harsh chemicals, and repeated use while maintaining dimensional stability and sealing integrity.
Engineered for Performance
LSRParts manufactures custom silicone caps and plugs for applications where dimensional consistency, material reliability, and repeatable production matter. Whether you need a simple tapered plug, a complex flanged cap, or a custom-molded masking solution with pull tabs, our engineering team ensures your parts are optimized for manufacturability and end-use performance.
- Withstands extreme temperatures and harsh chemicals
- Maintains dimensional stability and sealing integrity
- Optimized for manufacturability and repeatable production
Complete Manufacturing Solution
From initial design consultation to high-volume production, we provide end-to-end support for OEMs and product developers seeking custom silicone components.
DFM Review
Early manufacturing risk assessment
Material Selection
Optimized for your application
Mold Design & Sampling
Prototype validation before tooling
Mass Production
High-volume, repeatable output
Comprehensive Manufacturing Capabilities
We offer multiple molding technologies to produce custom silicone caps and plugs, ensuring the right process is matched to your part geometry, tolerance requirements, and production volume.
LSR Injection Molding
For high-precision, high-volume silicone caps and plugs, Liquid Silicone Rubber (LSR) injection molding offers unmatched repeatability and tight tolerances.
- Process
- LSR Injection Molding
- Max Part Envelope
- 300 × 200 × 100 mm
- Hardness
- 10–80 Shore A
- Tolerance
- ±0.05 mm
- Critical Tolerance
- Down to ±0.02 mm
- Repeatability
- Approx. ±0.1 mm
- Production Scale
- Prototype to High-volume
- Mold Cavities
- Single / Multi (up to 3–5M shots)
Silicone Compression Molding
Compression molding is an excellent, cost-effective process for larger silicone caps, heavy-duty plugs, and lower-volume production runs.
- Process
- Compression Molding
- Max Size
- 2500 × 2000 × 1000 mm
- Tolerance
- ±0.2 mm
- Small Part Cavity Tolerance
- ±0.1–0.2 mm
- Repeatability
- Approx. ±0.1 mm
- Best For
- Large parts, low-volume runs
LSR Overmolding
When a silicone cap or plug requires a rigid core for structural support, threading, or mechanical fastening, our LSR overmolding capabilities provide robust solutions.
Plastic Substrates
PC, PA, PBT, PPSU, PPA, PEI
Metal Substrates
Aluminum, Stainless Steel, Brass, Copper
Bonding
Chemical and mechanical bonding strategies
From DFM to Mass Production: Our Approach
A reliable custom silicone cap or plug starts before the mold is built. Our engineering team conducts a thorough DFM review of your part geometry, wall thickness, sealing features, draft angles, undercuts, and flash requirements. We also evaluate material hardness, shrinkage rates, and expected production volumes (ideally 100,000+ pcs annually) before tooling begins.
This proactive approach helps identify manufacturing risks early, giving OEMs and Tier suppliers a clear, predictable path from prototype validation to stable mass production.
Typical Project Workflow
Advanced Tooling & Mold Making
High-quality silicone caps and plugs require high-precision tooling. LSRParts operates advanced in-house tooling facilities equipped with 3-axis/5-axis CNC machining, Sinker EDM, and Wire EDM.
High-Performance Silicone Materials
The success of a silicone cap or plug depends heavily on material selection. We offer a comprehensive matrix of silicone compounds tailored to your specific application environment:
High-Temperature Silicone
Ideal for powder coating masking, engine components, and industrial ovens.
Fluorosilicone
Required for automotive and aerospace applications involving fuel, oil, and harsh chemical exposure.
Medical & Food Grade LSR
Biocompatible and platinum-cured silicones for healthcare devices, tubing seals, and food/beverage valves.
General Purpose LSR
Excellent for industrial sealing, electronics protection, and environmental masking.
Custom Compounds
Formulated for specific hardness, color matching (Pantone/RAL), or unique environmental resistance.
Secondary Operations & Post-Processing
LSRParts provides a full suite of secondary operations to deliver production-ready silicone caps and plugs:
Post-Curing
Enhances material properties
Precision Trimming & Die Cutting
Clean, accurate finishing
Punching & Slitting
X/Y and valve slitting
Pad Printing & Laser Marking
Custom identification options
Assembly & Functional Testing
Quality assurance verified
Custom Packaging
Tailored to your requirements
Ideal Applications for Custom Silicone Caps & Plugs
Our custom silicone caps and plugs are designed for OEMs and Tier suppliers across highly regulated and performance-critical industries:
Automotive & EV
Masking plugs for E-coating, connector seals, wire seals, battery enclosure plugs, and sensor seals.
Pumps, Valves & Fluid Control
Custom sealing plugs, check valve components, and port caps.
Electronics & Sensors
Waterproof port covers, housing seals, and overmolded protective caps.
Medical & Healthcare
Septa, sterile port caps, device seals, and fluid line plugs.
Industrial Surface Finishing
High-temp masking caps and pull-plugs for powder coating, plating, and anodizing lines.
Partner with LSRParts
LSRParts is dedicated to supporting engineering teams with high-value, repeat-production silicone components. If you have custom drawings, new tooling requirements, and a need for precision silicone caps and plugs, contact us today to initiate a DFM review and discuss your project requirements.
Request a DFM Review
Share your project details and our engineering team will respond promptly.