Two-Component Piston Venting and Sealing Design
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Solution Overview
Problem
Existing two-component pistons face issues with air trapping and reduced storage life due to insufficient attachment and sealing between the piston cover and body, as well as sprue marks from injection molding that interfere with valve operation, leading to reduced storage life of materials in cartridges.
Innovation Solution
A method of forming the piston cover first and then the piston body, with a non-releasable connection and strategic placement of injection points to minimize sprue marks, ensuring a reliable attachment and effective venting, thus improving the storage life of materials in cartridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the piston cover and piston body are attached using conventional methods, then the piston can be manufactured, but the attachment is insufficient leading to poor sealing and air leakage
Solution Approach 1:
The piston body and piston cover are merged into a single integral component through injection molding, eliminating the separate attachment interface that caused sealing problems. This combines two previously separate parts into one unified structure, ensuring perfect sealing without additional assembly complexity.
Solution Approach 2:
The single-piece piston design performs multiple functions simultaneously: it provides sealing, structural support, and material containment without requiring separate components. This multi-functional integration resolves the sealing reliability issue while maintaining manufacturing simplicity.
2Productivity
If air is trapped in the cartridge during filling, then the filling process is faster, but the stored material reacts with air reducing storage life
Solution Approach 1:
Air is extracted or removed from the cartridge during the filling process through the piston design that allows air to be displaced and vented. The piston structure enables air to be taken out as the material is injected, allowing fast filling while preventing air from remaining in contact with the stored material.
Solution Approach 2:
Air venting channels are pre-formed in the piston structure during manufacturing. These channels are prepared in advance to automatically vent air during filling, enabling the filling process to proceed quickly while the pre-designed pathways ensure air is continuously removed to protect storage life.
3Ease of manufacture
If sprue marks are present on the piston from injection molding, then the manufacturing process is simpler, but the sprue marks interfere with valve operation
Solution Approach 1:
The injection points and sprue mark locations are strategically positioned in areas of the piston that do not interfere with valve operation. By applying local quality consideration to the molding design, sprue marks are placed in non-critical zones, maintaining manufacturing simplicity while preserving valve functionality.
Solution Approach 2:
Instead of trying to eliminate sprue marks entirely (which would complicate manufacturing), the approach inverts the problem by positioning them in locations where they do not matter for valve operation. This reverses the conventional approach of placing injection points for optimal filling, instead placing them to avoid operational interference.
4Ease of operation
If expensive needle valves are used in injection molding to minimize sprue marks, then valve operation is not interfered with, but the manufacturing cost increases
Solution Approach 1:
The patent uses standard, inexpensive injection molding valves instead of expensive needle valves. By accepting that simple valves will create sprue marks, the design compensates through strategic positioning rather than expensive equipment, achieving the same operational result at lower cost.
Solution Approach 2:
Instead of using complex needle valve technology, the patent copies the functional outcome (non-interfering sprue mark placement) through a simpler, cheaper injection molding approach. The sprue mark position is designed to achieve the same operational effectiveness as needle valves would provide, but without the high cost.
Data Source
AI summary
A method of making a two-component piston, the two-component piston including a piston cover as the first component and a piston body as the second component. The piston cover is arranged adjacent to the piston body and is configured to be moved relative to the piston body.