Coating Nozzle Shutter Pressure Control for Uniform Film Thickness
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Solution Overview
Problem
Conventional coating devices face challenges in achieving uniform coat thickness due to pressure loss in the coating liquid feed system, leading to gradual thickness changes at the start and end of application, and issues with shutter members bending under pressure causing leakage.
Innovation Solution
A coating device with a rotatable shutter member in the coating liquid reservoir and a gas feed regulation means to control pressure, allowing quick start and stop of coating application, and maintaining uniform thickness by regulating pressure on the coating liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coating liquid is fed under predetermined pressure through feed pipe, then coating liquid can be supplied to application nozzle, but pressure loss causes gradual thickness increase at start and end of coating application
Solution Approach 1:
The system pre-fills the coating liquid reservoir in the application nozzle before coating starts, and pre-regulates the pressure in the reservoir. This preliminary preparation eliminates the delay at coating start caused by pressure loss in the feed pipe, allowing immediate discharge of coating liquid at the correct pressure when the shutter opens.
Solution Approach 2:
The coating liquid reservoir acts as an intermediary between the feed pipe and the discharge port. By decoupling the feed system from the discharge system, the reservoir buffers the pressure loss effects, allowing the discharge to occur at regulated pressure independent of feed pipe pressure variations during start and end of coating.
2Productivity
If pressure is decreased to stop coating liquid discharge, then coating application can be terminated, but discharge stops gradually causing thickness variation at end of coating
Solution Approach 1:
The system prepares the shutter member in advance to close the discharge port. When coating needs to stop, the shutter simply closes the port, providing immediate termination of discharge without gradual pressure reduction, thus preventing thickness variation at the end of coating.
3Object-affected harmful factors
If shutter member is disposed under discharge port to prevent solvent vaporization, then vaporization is prevented, but shutter and cylinder rod bend under pressure causing coating liquid leakage
Solution Approach 1:
The system replaces the mechanical cylinder rod that pushes the shutter with a gas pressure system. Gas is fed into the reservoir to push the shutter open, eliminating the need for a long mechanical rod that would bend under pressure. The shutter is now actuated by gas pressure differential rather than mechanical force transmission.
Solution Approach 2:
The system uses gas pressure to actuate the shutter member and to regulate the pressure in the coating liquid reservoir. This pneumatic system replaces the mechanical linkage, allowing the shutter to open and close reliably without structural bending, while maintaining the seal to prevent solvent vaporization.
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
Enables rapid initiation and termination of coating application without thickness variations, ensuring uniform coat thickness on the coated object by controlling pressure with the shutter member and gas regulation.
Implementation Method 1
the gas feed regulation means, with the coating liquid fed into the coating liquid reservoir, feeding a gas into the coating liquid reservoir to regulate the pressure on the coating liquid in the coating liquid reservoir to be at the given level
Implementation Method 2
a shutter member which is rotatable in the coating liquid reservoir to open or close space between the coating liquid reservoir and the slit-shaped discharge port
Implementation Method 3
the coating liquid is fed from the coating liquid feed device to the application nozzle via the coating liquid feed pipe under a predetermined pressure. While discharging the coating liquid from the slit-shaped discharge port onto the surface of the coated object
Data Source
Figure 1
Figure 2~3
Figure 4(A)~4(D)
AI summary
In a coating device wherein a relative movement between an application nozzle 10 located above a coated object W and the coated object is effected to apply a coating liquid P in a coating liquid reservoir 11 of the application nozzle onto a surface of the coated object via a slit-shaped discharge port 11, the coating device includes: a shutter member 13 rotatable in the coating liquid reservoir to open or close space between the coating liquid reservoir and the slit-shaped discharge port; and a gas feed regulation means 32 for regulating the pressure on the coating liquid in the coating liquid reservoir, and is characterized in that in a state where the gas feed regulation means maintains the pressure on the coating liquid in the coating liquid reservoir to be at a given level, the shutter member is rotated to open or close space between the coating liquid reservoir and the slit-shaped discharge port.