Which Process Is Best for Silicone Valve Manufacturing?

Are you choosing a production route for silicone valves — whether cross slit valves, one-way silicone valves, or high-volume ketchup valves — and wondering whether Liquid Silicone Rubber Transfer Molding (LSR-TM) or Liquid Silicone Rubber Injection Molding (LSR-IM) is the better fit? At The term "YJCPolymer" appears to be a proper noun, likely a brand or company name, and typically, proper nouns do not get translated. Therefore, it would remain "YJCPolymer" in German as well. If you have additional context or need further assistance, feel free to provide it! we help OEMs and designers evaluate trade-offs every day. This guide explains both processes, their pros and cons, the two injection feeding styles, and a practical decision framework so you can pick the right manufacturing path for your valve program.

Liquid Silicone Transfer Molding (LSR-TM)

Transfer molding uses pre-measured LSR placed into a pot or chamber, then mechanically forced (transferred) into a closed mold cavity. Historically favored for smaller runs or certain geometries, LSR transfer molding remains relevant where lower tooling cost or specific runner layouts are needed.

Vorteile

• Lower upfront tooling cost for small-to-medium cavities (sometimes simpler core/cavity tooling).
• Good for medium-complexity parts and for shops with existing transfer press capability.
• Useful for prototyping and short-run production without full investment in fully automated injection lines.

Disadvantages

• Higher cycle time and lower throughput vs modern injection machines — transfer strokes add time.
• Greater operator labor (often semi-automated) increases per-piece cost and variability.
• Less precise shot-to-shot control of material dosing; potential for inconsistent fill and cosmetic variation.
• More difficult to scale to very high volumes economically.
• Usually inferior for high-cavity tooling where precise split-shot metering matters.

Flüssigsilikon-Spritzguss (LSR-IM)

LSR injection molding feeds metered liquid silicone through a heated barrel and high-pressure pump into the mold. Modern LSR injection systems (with automatic dosing) are engineered for high repeatability and volume.

Vorteile

• High cycle rates and excellent repeatability — ideal for mass production of one way silicone valves and other high-volume parts.
• Precise shot control, consistent weight, and excellent surface finish for cosmetic-critical components (valve seats, slit geometry).
• Superior capability for multi-cavity tooling (8–64+ cavities) to drive down unit cost at scale.
• Integrates well with automation: robot pick, post-cure ovens, vision inspection — reduces labor and improves yield.
• Best choice for overmolding or insert-molding workflows (e.g., molding a silicone valve onto a plastic cap or housing).

Disadvantages

• Higher initial capital and tooling investment (but much lower unit cost at volume).
• More complex machine setup and qualification required (process control, hot runner systems for LSR).
• For very small pilot runs the economics may not justify the tooling cost without projected scale.

Two Injection Methods of Silicone

When using LSR-IM there are two basic material feeding/shot delivery approaches:

Manual Liquid Silicone Material Feeding

• Operator charges the machine pot manually or semi-automatically.
• Lower automation cost; acceptable for prototyping, low-volume production and color-change flexibility.
• Downsides: higher labor, longer cycle times, increased human error risk, and inconsistent shot weights if not tightly controlled.

Automatic Liquid Silicone Material Feeding

• Metered, servo-driven pumps and automated material supply deliver consistent shot weights and stable process conditions.
• Essential for high-cavity molds, multi-shift production, and food/medical-grade parts requiring strict process control (e.g., cross silt valves, ketchup valves).
• Enables integrated automation, traceability, and reduced scrap.

Which Is the Better Choice for Your Silicone Valves?

Use this decision framework:

1. Volume & Unit Cost Targets
   • Low volume (≤ a few thousand pcs/month): LSR-TM or prototype IM with manual feed may be acceptable.
   • Medium to high volume: LSR-IM with automatic feeding becomes cost effective and is preferred.
2. Tolerance, Cosmetic & Functional Precision
   • Tight dimensional control, consistent slit geometry, and cosmetic finish → LSR-IM (automatic) is superior.
3. Part Complexity & Overmolding Needs
   • Overmolding onto rigid caps, integrated assemblies, or multi-material parts → LSR-IM with automation.
4. Regulatory & Traceability Requirements
   • Medical/food applications demand consistent process control, validated cycles and material traceability → LSR-IM with automated dosing and full lot documentation.
5. Lead Time & Tooling Budget
   • If tooling budget is constrained for a one-off run, transfer molding or low-cavity IM tooling can be used for development. For product launches, plan IM tooling investment amortized across forecast volume.
6. Scalability & Supplier Capabilities
   • Choose a manufacturing partner who can scale from prototype tooling to multi-cavity production and provide custom service, validation, and assembly.

YJCPolymer Capabilities & Recommendation

At YJCPolymer we operate both transfer and modern LSR injection lines and guide customers to the right path:

• For prototypes, design validation and initial market tests — we often start with transfer or small-run IM.
• For true production of one way silicone valve, cross silt valves, or ketchup valves, we recommend LSR-IM with automatic feeding, high-cavity tooling, integrated post-cure ovens, and in-line inspection to ensure consistent performance and cost efficiency.

We also offer full custom service: DFM reviews, pilot tooling, process validation (IQ/OQ/PQ), and ongoing supplier management so your valve program moves smoothly from design to scale.

If you’re ready to pick a process or need a production quote, contact YJCPolymer. Share your target volumes, performance specs, and regulatory needs — we’ll propose a manufacturable plan and a clear cost/time comparison so you can make an informed decision.