Post-Print Vacuum Degassing for Bubble-Free Silicone Gaskets
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Solution Overview
Problem
The turbulent nature of the screen-printing process introduces air bubbles into wet gasket material, which is detrimental to the reliability of proton-exchange membrane fuel cells, and existing processes lack effective methods for bubble removal.
Innovation Solution
A degassing chamber with a vacuum source and reservoir is used to create and maintain a partial vacuum, allowing freshly-printed workpieces to be subjected to vacuum degassing, removing bubbles from the printed material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If screen-printing process is used to apply RTV silicone material onto workpiece, then printing efficiency and productivity are improved, but air bubbles are introduced into the wet material which deteriorates reliability
Solution Approach 1:
The patent applies vacuum degassing immediately after printing while the material is still wet and bubbles are present. The degassing chamber is positioned directly in the printing machine's path, allowing bubbles to be removed before the material cures and becomes unusable. This preliminary action prevents the harmful effect from manifesting in the final product.
Solution Approach 2:
The patent converts the harmful air bubbles introduced by screen-printing into a detectable and removable condition. By applying vacuum immediately after printing, the bubbles rise to the surface where they can be broken and removed. The harmful turbulence that introduces bubbles is followed by a process that exploits the same turbulent state to bring bubbles to the surface for removal.
2Reliability
If vacuum degassing is applied to freshly-printed workpieces, then air bubbles are removed from the material, but additional time and equipment complexity are required
Solution Approach 1:
The patent merges the printing machine and degassing chamber into a single integrated unit. The degassing chamber is positioned directly in the path of the printing machine, allowing workpieces to move continuously from printing to degassing without manual intervention or separate handling. This integration reduces overall system complexity despite adding the degassing function.
Solution Approach 2:
The degassing chamber is designed to handle multiple workpiece types and printing configurations within a single device. The vacuum system serves both to remove bubbles from printed material and to maintain a consistent processing environment for different material viscosities and workpiece sizes, reducing the need for multiple specialized devices.
3Reliability
If vacuum degassing is applied to freshly-printed workpieces, then air bubbles are removed from the material, but production time is increased
Solution Approach 1:
The patent implements continuous degassing where workpieces move through the degassing chamber on a conveyor system. The vacuum is applied continuously as each workpiece passes through, rather than requiring batch processing or stopping the production line. This maintains continuous production flow while ensuring complete bubble removal.
Solution Approach 2:
The patent uses a rapid vacuum pulse that acts quickly to remove bubbles before the material begins to cure. The degassing chamber is designed with optimized airflow patterns that rapidly draw bubbles to the surface and break them, minimizing the time each workpiece needs to be exposed to vacuum while ensuring complete bubble removal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The degassing chamber effectively reduces air bubbles in printed gasket material to operationally acceptable levels, ensuring reliable fuel cell operation.
Implementation Method 1
a vacuum source for creating at least a partial vacuum, and a vacuum reservoir in fluid communication with the vacuum source such that the at least partial vacuum may be produced and maintained within the vacuum reservoir
Implementation Method 2
subject them to an at least partial vacuum, thus removing bubbles from the printed material
Data Source
AI summary
A degassing chamber for degassing a material located on a workpiece, comprises a vacuum source and a vacuum reservoir in fluid communication with the vacuum source, a secondary chamber, a port valve which is movable between an open position to allow passage of a workpiece therethrough between the exterior of the degassing chamber and the secondary chamber and a closed position in which the port valve is fluidly sealed, and a reservoir valve which is movable between an open position to provide fluid communication between the secondary chamber and the vacuum reservoir and a closed position in which the reservoir valve is fluidly sealed. The degassing chamber may be provided subsequent to a printing machine in a production line, and has particular application for degassing silicone material when producing fuel cells.