Aluminum Strip Flatness via Segmented Coiling and Stretch-Leveling
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Solution Overview
Problem
Large aluminum coils used in lithographic plates often suffer from deterioration in flatness due to uneven winding tension and increased tension during high-temperature drying processes, leading to edge buckling and surface irregularities.
Innovation Solution
The method involves rolling the aluminum strip at least twice as wide as the final product, dividing it into two halves, and performing secondary cold rolling to eliminate edge burrs, followed by stretch-leveling and trimming to maintain flatness even under increased coil tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the coil size is enlarged to improve production efficiency, then productivity increases, but the degree of flatness deteriorates due to uneven winding tension
Solution Approach 1:
The aluminum strip is divided into two separate coils by cutting it along the centerline. Each coil contains only one half of the original strip width, ensuring that neither coil develops significant crown height that would cause flatness deterioration. This segmentation allows both coils to be produced with good flatness while still achieving the productivity benefit of using larger coils.
2Reliability
If winding tension is increased to ensure smooth passage during high-temperature drying, then processing stability improves, but degree of flatness deteriorates due to creep deformation
Solution Approach 1:
The strip is cut into two halves before coiling, preventing the development of crown height and uneven thickness distribution that would lead to creep deformation under tension. This preliminary action eliminates the root cause of flatness deterioration, allowing high winding tension to be applied during subsequent processing without causing buckling or surface irregularities.
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 approach ensures that the aluminum strip retains excellent flatness during storage and processing, preventing edge waving and surface irregularities, even when subjected to high temperatures and increased tension.
Implementation Method 1
thicker portions receive a large tension and hence undergo creep deformation with time after coiling
Implementation Method 2
The aluminum strip in the form of coil or sheet is required to be excellent in degree of flatness if it is to be used as lithographic plates. Therefore, it usually undergoes stretch-leveling by a stretch-leveler after rolling so that it is freed of surface irregularities due to uneven stress it receives at the time of rolling.
Data Source
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AI summary
Disclosed herein is a method for producing aluminum strips by rolling an aluminum strip at least twice as the final product, dividing the rolled strip into two halves, and winding up each of the divided strips into a coil. The method includes the steps of hot rolling an aluminum ingot, cold rolling the hot-rolled aluminum strip, thereby giving a strip at least twice as wide as the final product, cutting the wide strip longitudinally into two or more portions in the widthwise direction, and cold rolling the divided narrow strip. The secondary cold rolling is followed by trimming, stretch-leveling, and coiling. The resulting aluminum strip maintains good degree of flatness even though it experiences a high coil tension.