Small-Diameter Gravure Roll Coating with Reverse Doctor Blade
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Solution Overview
Problem
Gravure kiss coaters face challenges in stabilizing the coating process due to rapid paint drying, especially when using high-speed operations, leading to unstable coating performance and requiring larger dryer spaces.
Innovation Solution
A gravure kiss coater with a small-diameter gravure roll (45-150 mm) and a paint feeder system featuring a doctor blade that contacts the coating portion from the opposite direction of rotation, reducing paint exposure and preventing lift, along with a sealed paint feeder configuration to minimize air introduction and ensure accurate coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the speed of travel of the substrate is increased to improve productivity, then the coating process becomes faster, but the drying space must be much larger
Solution Approach 1:
The invention changes the key parameter of gravure roll diameter to a small size (45-150 mm), which fundamentally alters the coating mechanism to enable high-speed operation without proportionally increasing dryer space requirements
2Productivity
If the substrate travel speed is increased to improve productivity, then coating efficiency increases, but paint drying before application causes unstable coating
Solution Approach 1:
By changing the gravure roll diameter to a small size (45-150 mm), the invention reduces the paint exposure time to a minimum, enabling high-speed substrate travel while maintaining stable coating despite paint's tendency to dry quickly
Solution Approach 2:
The doctor blade is positioned to contact the coating portion from a reverse angle, performing preliminary paint thickness reduction and control before the paint is applied to the substrate, ensuring consistent coating at high speeds
3Ease of operation
If a doctor blade is disposed at a natural angle to easily press close to substrate, then paint application is simplified, but paint pressure lifts the blade and causes excessive paint feeding
Solution Approach 1:
The doctor blade is disposed at an inverted angle relative to the natural angle, contacting the coating portion from a reverse angle (opposite to rotation direction). This inversion prevents paint pressure from lifting the blade while maintaining ease of positioning and achieving precise paint thickness control
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 enables stable and accurate coating even with paints that dry quickly, maintaining coating performance and allowing for compact dryer spaces, enhancing production efficiency and versatility.
Implementation Method 1
A gravure kiss coater is an apparatus configured to coat a flat sheet-like substrate that travels while being stretched and floating by rotating and simultaneously pressing a gravure roll on which paint is deposited against the substrate
Implementation Method 2
a doctor blade extending along the small-diameter gravure roll and having a distal end contacting the coating portion moving toward a location at which the coating portion contacts the substrate
Implementation Method 3
a paint feeder extending along the small-diameter gravure roll and configured to feed paint to the coating portion
Data Source
AI summary
A gravure kiss coater 1 includes a paint feeder 30 placed along a small-diameter gravure roll 10 having an outside diameter D in a range of 45-150 mm. The paint feeder 30 includes a doctor blade 32, a case 31, and a coating feed path 34, 35. A distal end 32a of the doctor blade 32 is directed in a direction opposite to a direction of rotation of the small-diameter gravure roll 10, and the small-diameter gravure roll 10 is capable of contacting the substrate S within a range of rotation angles equal to or less than 90° from the distal end 32a of the doctor blade 32.