Jan. 29, 2026
In medical, food, automotive, and precision industrial applications, silicone valves serve as critical functional components responsible for sealing, flow control, and fluid direction. Their stability and reliability are not determined by design alone — manufacturing process selection plays an equally decisive role.
Today, silicone valve production mainly follows two technical routes: solid silicone molding and Liquid Silicone Rubber (LSR) molding. A thorough understanding of their fundamental differences in material behavior, processing logic, and end-use performance is essential for achieving both product qualification and scalable mass production.
1.1 Solid Silicone Molding
Mature and reliable, with advantages in cost control and flexibility
Solid molding uses high-consistency rubber (HCR) silicone in sheet or block form, typically covering a Shore hardness range from 20A to 80A or higher. The primary process is compression molding:
Pre-cut silicone material is placed into a heated mold cavity. Under elevated temperature (approx. 150–200°C) and pressure, the material flows, fills the cavity, and completes crosslinking (vulcanization).
Key advantages include:
Relatively simple mold structures with lower initial tooling investment
Mature and well-established processing technology
Suitable for silicone valves with simple geometries
Cost-effective for small batches or prototyping stages
However, due to limited material flowability and greater reliance on manual handling, automation levels and part-to-part consistency are comparatively lower.
1.2 Liquid Silicone Rubber (LSR) Molding
The benchmark for precision and automation
LSR molding uses low-viscosity, two-component liquid silicone rubber. The core process is precision injection molding:
Components A and B are accurately metered and mixed before being injected into a heated mold. Under a platinum-catalyzed addition curing system, the material rapidly crosslinks and solidifies.
LSR process characteristics:
Highly automated production with excellent process stability
Molds commonly use cold runner systems, resulting in minimal material waste
Capable of replicating micro-scale features with exceptional batch consistency
Although tooling and equipment investment are higher, LSR provides a robust foundation for high-precision and high-reliability silicone valve manufacturing.
Precision and Structural Complexity
Thanks to its superior flowability, LSR easily fills micro-channels, ultra-thin walls, and complex 3D geometries. Dimensional tolerances can be consistently maintained at ±0.05 mm or tighter over long production runs.
Solid molding is better suited for simpler geometries with relatively relaxed tolerance requirements.
Material Purity and Product Performance
LSR uses a platinum-cured system with no by-products and no plasticizers, ensuring high material purity. It readily meets FDA, LFGB, and medical-grade biocompatibility requirements.
In terms of temperature resistance (typically −50°C to above 200°C), aging resistance, elastic recovery, and long-term sealing stability, LSR products generally outperform solid-molded counterparts.
Production Efficiency and Cost at Scale
LSR supports continuous, unattended production with short cycle times and near-100% material utilization. In medium-to-high production volumes, the per-unit total cost becomes increasingly competitive.
Solid molding remains advantageous for low-volume production where flexibility is more important than automation.
Design Freedom and Functional Integration
LSR enables overmolding with plastics or metals, reducing part count, minimizing assembly error, and lowering leakage risk. This level of functional integration is difficult to achieve with traditional solid molding.
LSR is the preferred choice when:
Valve structures are complex, miniature, or highly tolerance-sensitive
Applications fall under medical, food, or pharmaceutical regulations
Long-term sealing reliability and environmental resistance are critical
Stable, large-scale mass production is planned
Overmolding is desired for structural integration and functional optimization
Solid Silicone Molding can be considered when:
Production is limited to small batches or prototype validation
Product geometry is simple with modest precision requirements
Initial project budgets are limited and volume expectations are low
Very high hardness materials (above 70A) are required
It is important to recognize that silicone valves are precision functional components. Regardless of whether solid or LSR molding is selected, the ultimate performance ceiling depends on the supplier’s engineering capabilities, including:
Absolute mold precision — Mold machining accuracy, runner design, and venting directly affect slit consistency, opening sensitivity, and service life
Engineering-grade raw materials — Material clarity, batch stability, rheological behavior, and catalyst purity form the foundation of long-term reliability
Deep understanding of valve mechanics — A capable supplier should deliver systematic solutions covering material selection, mold design, and processing parameters, rather than simply “manufacturing to print”
Liquid Silicone Rubber (LSR) injection molding has become the mainstream process for high-end and mission-critical silicone valve applications due to its superior precision, purity, efficiency, and design flexibility. Meanwhile, solid silicone molding remains a practical option for low-volume validation and structurally simple products.
A rational selection should go beyond the process name itself and include a thorough evaluation of the supplier’s capabilities in high-precision tooling, raw material control, and functional component engineering.
Before finalizing any decision, performance validation using real silicone valve samples remains an essential step to ensure successful product implementation.
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