Print Head Sealing Reliability via Valve Element Extraction
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Solution Overview
Problem
Existing print heads for applying coatings, such as paint to motor vehicle body components, face challenges with complex manufacturing processes, limited miniaturization of valve elements, and fluctuations in valve lift due to elastomer inserts, leading to inefficiencies and overspray issues.
Innovation Solution
A print head design featuring a nozzle plate with movable valve elements and seals arranged on the nozzle plate rather than the valve elements, utilizing a flat seal for physical contact and a conical or hemispherical shape fit for improved sealing, along with a flexible actuator diaphragm or magnetic drive for precise control, and potentially combining seals on both the valve element and nozzle plate for enhanced sealing and mechanical stop functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an elastomer insert is used to seal the nozzle against the valve needle, then sealing is achieved, but the manufacturing process becomes complex and manufacturing precision is limited
Solution Approach 1:
The elastomer insert is extracted from the valve needle and relocated to the nozzle. This separates the sealing function from the moving valve element, simplifying valve needle manufacturing while maintaining sealing reliability through the elastomer's compliance at the stationary nozzle interface.
Solution Approach 2:
Instead of placing the elastomer insert on the moving valve needle as in conventional designs, the patent inverts the arrangement by positioning the elastomer insert on the stationary nozzle. This reversal simplifies the moving parts while achieving sealing through the elastomer's deformation at the nozzle opening.
2Reliability
If a valve needle with elastomer insert is used, then sealing is achieved, but miniaturization is limited and nozzle spacing cannot be reduced below a certain limit
Solution Approach 1:
The elastomer insert is extracted from the valve needle structure, allowing the valve needle to be miniaturized without the space requirements of a traditional elastomer insert. This enables reduced nozzle spacing and smaller overall printhead dimensions while maintaining sealing functionality.
Solution Approach 2:
By inverting the elastomer insert location to the stationary nozzle rather than the moving valve needle, the design eliminates the need for large moving valve elements, enabling miniaturization and denser nozzle arrangements.
3Reliability
If an elastomer insert is used for sealing, then sealing is achieved, but manufacturing precision fluctuations cause large variations in valve stroke
Solution Approach 1:
The elastomer insert is extracted from the moving valve needle and placed in the stationary nozzle, isolating the compliance element from the precision moving parts. This separation ensures that manufacturing variations in the elastomer do not directly affect valve stroke consistency, as the valve needle geometry remains precise and rigid.
Solution Approach 2:
Inverting the elastomer insert location to the stationary nozzle removes the source of manufacturing variability from the moving valve assembly, thereby improving valve stroke consistency while maintaining sealing through the elastomer's deformation at the fixed nozzle interface.
Data Source
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AI summary
The invention relates to a printhead for applying a coating agent to a component, in particular for applying a paint to a motor vehicle body component, comprising a nozzle plate (1), a nozzle (2) in the nozzle plate (1) for dispensing the coating agent, and a valve element (9, 11) movable relative to the nozzle plate (1) for controlling the dispensing of the coating agent through the nozzle (2), wherein the movable valve element (9, 11) closes the nozzle (2) in a closed position, whereas the movable valve element releases the nozzle (2) in an open position, and with a seal (11, 12) for sealing the nozzle (2) against the movable valve element (9, 11) in the closed position of the valve element (9, 11). The invention provides that the seal (11, 12) is not designed as an elastomer insert on the valve element (9, 11).