This medical check valve was developed for a diagnostic reagent kit that requires reliable sealing and repeated liquid extraction. Medical devices typically have long development cycles, and this project was no exception. From early design validation to final production approval, the development process took several years to ensure full reliability and stability.
The valve is manufactured from biocompatible liquid silicone rubber (LSR) and designed as a precision sealing component inside the reagent cartridge. Its function is to allow controlled extraction of reagent while maintaining excellent sealing performance to prevent leakage or contamination.
At the early stage of the project, the valve was designed according to standard dimensional tolerances and manufactured with a conventional precision mold.
However, during the customer's assembly line testing, an unexpected issue appeared. Some reagent kits were found to be missing valves during assembly. After detailed investigation, the root cause was identified as dimensional tolerance variation of the valve, which caused unstable positioning during automated assembly.
To solve this issue, our engineering team performed a full tolerance stack-up analysis. The results showed that the outer diameter tolerance had to be significantly tightened in order to guarantee stable assembly.
The final tolerance specification was defined as:
Outer Diameter: 16 mm ± 0.05 mm
Other Dimensions: ± 0.1 mm
Such tolerance control is significantly stricter than standard silicone valve production.
After confirming the new tolerance requirements, the Hopewell engineering team upgraded the mold design and manufacturing process.
Key improvements included:
High-precision mold machining equipment
Optimized mold structure to reduce dimensional variation
Improved cavity accuracy to achieve stable molding performance
With these upgrades, the new mold was able to consistently maintain the required ±0.05 mm precision, enabling the customer to smoothly transition to validated production within the scheduled timeline.
This silicone medical check valve is designed with a Y-shaped slit, which allows liquid extraction while maintaining a reliable sealing function.
Because the reagent must be extracted repeatedly through the slit, the valve requires:
Excellent elastic recovery
Stable sealing performance
Consistent opening pressure
During development, multiple silicone material formulations were evaluated before selecting the optimal medical-grade LSR that provides the best balance between flexibility, resilience, and sealing reliability.
Due to the customer's high production demand, the valve is manufactured using fully automated precision processes.
Key manufacturing steps include:
LSR injection molding for high consistency
High-precision automatic punching for the Y-shaped slit
Automated outer profile punching to maintain accurate dimensions
This fully automated production ensures:
Stable product performance
High dimensional consistency
Reliable large-scale manufacturing capability
After implementing the optimized mold design and precision manufacturing process, the valve successfully met the customer's strict specifications for:
Assembly stability
Sealing performance
Dimensional accuracy
High-volume production
The final product has been successfully integrated into the customer's diagnostic reagent system.
At Hopewell, we specialize in designing and manufacturing custom silicone valves for demanding applications.
Our solutions cover industries such as:
Medical and diagnostic devices
Food and beverage packaging
Personal care and household products
Industrial dispensing systems
With advanced LSR injection molding technology and precision slit processing, we are capable of producing valves with tight tolerances and stable performance for high-volume production.
If you are developing a high-precision silicone valve for your product, feel free to contact our engineering team to discuss your project.
If you have any questions about us, you can leave a message online or contact us!
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