Vacuum Degassing Chamber for Bubble-Free Printed Silicone Gaskets
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Solution Overview
Problem
The turbulent screen-printing process for producing RTV silicone gaskets in PEM fuel cells introduces air bubbles into the gasket material, which are detrimental to the reliability of the fuel cells, and there is a lack of effective methods or apparatus for removing these bubbles from freshly printed workpieces.
Innovation Solution
A production line incorporating a degassing chamber that uses a vacuum source to create a partial vacuum, allowing freshly printed workpieces to be treated and bubble-free, with a vacuum reservoir to maintain the vacuum and a transport mechanism to move workpieces through the degassing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If screen-printing process is used to apply RTV silicone material, then production efficiency is improved, but air bubbles are introduced into the material
Solution Approach 1:
The patent applies vacuum degassing immediately after screen-printing while the RTV silicone material is still wet and before it cures. This preliminary action removes air bubbles introduced during printing, ensuring the material is bubble-free before it sets and becomes structurally sound, thus maintaining both production efficiency and gasket reliability
Solution Approach 2:
The patent creates a vacuum environment (inert atmosphere without air) within the degassing chamber to prevent air from being present during the degassing process. This vacuum environment allows air bubbles to be extracted from the wet RTV silicone material without introducing additional air, resolving the contradiction between efficient printing and bubble-free results
2Reliability
If vacuum degassing is applied to freshly printed workpieces, then air bubbles are removed from material, but additional processing time is required
Solution Approach 1:
The vacuum degassing is performed as a preliminary step immediately after printing and while the material is still wet. This timing is critical because once the RTV silicone cures, bubbles can no longer be removed. By performing this action at the optimal moment in the process, the patent achieves bubble removal without requiring additional time after curing
Solution Approach 2:
The patent integrates the vacuum degassing step into the continuous production flow, maintaining the workflow without significant interruptions. The system is designed to handle workpieces continuously through printing, degassing, and curing stages, minimizing idle time and ensuring the degassing operation does not become a bottleneck in the production line
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 solution effectively reduces the presence of air bubbles in the printed gasket material, enhancing the reliability and efficiency of PEM fuel cell production by ensuring bubble-free gaskets, and can be applied to various types of workpieces beyond fuel cells.
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
Data Source
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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.