Coating Apparatus Bubble Prevention via Rotatable Supports
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coating apparatuses face challenges in preventing air bubbles from being trapped during high-speed coating, leading to coating loss-like defects and other defects.
Innovation Solution
The proposed coating apparatus includes a container with an upstream and downstream side cover, a rotatable coating bar, and a plurality of rotatable supports. The design features a specific arrangement of clearances and overlaps between the coating bar and the covers, as well as the use of an in-liquid cover, to prevent air bubbles from being trapped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotatable supports are used to support the coating bar, then frictional resistance is reduced and abrasion is minimized, but air bubbles are trapped in the contact part between the coating bar and supports causing coating defects
Solution Approach 1:
The patent introduces coating liquid as an intermediary substance between the coating bar and the rotatable supports. The coating liquid fills the contact interface, preventing air bubbles from being trapped while maintaining the low-friction benefits of rotatable supports. This resolves the contradiction by mediating the interaction between the coating bar and supports.
Solution Approach 2:
The patent creates an environment filled with coating liquid rather than air in the contact zone between the coating bar and supports. By replacing the air atmosphere with coating liquid, the harmful air bubbles are eliminated from the contact interface, while the rotatable supports continue to provide reduced friction and abrasion.
2Object-affected harmful factors
If the container is filled with coating liquid to submerge contact parts, then air bubbles are less likely to be trapped, but accompanying flow causes liquid surface to ripple and air bubbles to be trapped
Solution Approach 1:
The patent applies different clearance designs at different locations: narrower clearances near the supports to reduce accompanying flow and prevent ripples, and wider clearances at other positions to allow proper coating liquid flow. This local differentiation of clearance quality resolves the contradiction between preventing air bubbles and avoiding ripple-induced air bubble generation.
Solution Approach 2:
The patent designs the clearance between the coating bar and covers to be dynamic rather than uniform, with varying widths at different positions along the coating bar. This dynamic clearance configuration allows the system to adapt to the accompanying flow generated by rotatable supports, preventing liquid surface ripples while maintaining effective air bubble prevention.
3Length of moving object
If a long rod coating bar is used, then the coating width is sufficient, but the coating bar deflects due to its own weight and reaction force
Solution Approach 1:
The patent combines multiple rotatable supports along the length of the coating bar to provide distributed support. By merging the support function across multiple contact points, the long coating bar is prevented from deflecting under its own weight and reaction forces, while maintaining its full length for adequate coating width.
Solution Approach 2:
The patent changes the support mechanism parameters by introducing rotatable supports with specific clearance configurations. These parameter changes allow the long coating bar to maintain stability by reducing deflection through proper support positioning and clearance control, while preserving the necessary coating bar length.
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
This solution effectively prevents air bubbles from being trapped during high-speed coating, reducing coating defects and ensuring a uniform coating process.
Implementation Method 1
The frictional resistance between the coating bar and the support unit can be reduced by supporting the coating bar in a circumscribed manner using these pairs of rotatable rollers
Implementation Method 2
The coating bar is rotated by frictional force generated between the coating bar and the web by being pressed to the web
Data Source
AI summary
A coating apparatus includes: a container configured to accumulate a coating liquid; a rotatable coating bar arranged at an opening part so that the coating bar has a clearance between the coating bar and a downstream side end of an upstream side cover and a clearance between the coating bar and an upstream side end of a downstream side cover and a rotation axis direction of the coating bar is directed in a longitudinal direction of the container; a plurality of rotatable supports intermittently arranged along the rotation axis direction of the coating bar; and an in-liquid cover extending in the longitudinal direction of the container.