Coating Flow Path Volume Control for Clean Liquid Cutoff
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Solution Overview
Problem
Existing coating devices experience dragging of coating liquid at the coating end portion due to insufficient pressure reduction at the discharge port, leading to incomplete liquid cutoff.
Innovation Solution
A coating device with a volume adjustment mechanism that includes a pair of volume adjustment parts inserted into the coating flow path from both ends, adjusting the flow path volume to reduce pressure near the discharge port, thereby facilitating complete liquid cutoff and preventing dragging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the supply valve is operated to reduce pressure inside the coating unit, then liquid cutoff at the discharge port is achieved, but the pressure reduction effect cannot sufficiently reach the discharge port when the valve is positioned away from the discharge port
Solution Approach 1:
The coating unit is segmented into multiple pressure control zones by dividing the flow path into first and second flow paths with separate control valves. This allows independent pressure control at different locations, enabling the discharge port to achieve sufficient pressure reduction for complete liquid cutoff while maintaining manageable device complexity through modular valve positioning.
2Ease of manufacture
If the supply valve is positioned far from the discharge port for structural reasons, then device assembly is simplified, but pressure reduction effect cannot reach the discharge port effectively causing coating liquid dragging
Solution Approach 1:
The flow path is segmented into first and second flow paths with separate control valves positioned at different locations. The first control valve can be positioned away from the discharge port for ease of assembly, while the second control valve is positioned near the discharge port to ensure effective pressure reduction and eliminate coating liquid dragging.
Solution Approach 2:
The second control valve acts as an intermediary pressure control element positioned between the first control valve and the discharge port. It transmits and amplifies the pressure reduction effect from the first valve to the discharge port, ensuring complete liquid cutoff while allowing the first valve to be positioned for ease of assembly.
3Productivity
If intermittent coating application is implemented to improve productivity, then coating speed increases and coating liquid loss decreases, but incomplete liquid cutoff causes dragging at coating end portion
Solution Approach 1:
The coating system uses segmented flow paths with independent control valves that enable precise pressure control during intermittent operation. When coating application stops, the control valves can rapidly reduce pressure in each flow path segment, ensuring complete liquid cutoff at the discharge port and preventing dragging at the coating end portion, thereby maintaining high coating quality during high-speed intermittent operation.
Solution Approach 2:
The control valves are positioned and configured to enable preliminary pressure reduction action before the coating application completely stops. This ensures that liquid cutoff occurs at the discharge port before the substrate moves away, preventing coating liquid dragging at the coating end portion and maintaining high manufacturing precision during intermittent high-speed operation.
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 device effectively suppresses coating liquid dragging at the end portion by ensuring sufficient pressure reduction at the discharge port, allowing for precise control of coating application and preventing excessive liquid application.
Implementation Method 1
the volume adjustment mechanism changes the volume of a coating flow path that supplies a coating liquid to a discharge port, thereby reducing pressure inside a coating unit so as to draw the coating liquid from the discharge port
Data Source
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AI summary
To provide a coating device that can suppress dragging of a coating liquid at a coating end portion. Specifically, provided is a coating device that applies a coating liquid to a substrate being conveyed, the device comprising a coating unit in which is formed a discharge port that is long in a width direction perpendicular to a transport direction of the substrate and a coating flow path that is connected to the discharge port and supplies a coating liquid to the discharge port, and a volume adjustment mechanism that changes the volume of the coating flow path, wherein the volume adjustment mechanism includes a volume adjustment part that is inserted into the coating flow path, and a drive unit that adjusts the insertion amount of the volume adjustment part.