Sub-Ambient Metal Rolling for Low-Melting Foil Production
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Solution Overview
Problem
Metals with low melting temperatures, such as lithium, indium, tin, and lead, are prone to tearing and fracturing during rolling into foils due to lack of mechanical strength at room temperature and tend to stick to work rollers.
Innovation Solution
A cooling subsystem is integrated into the rolling system to chill metals to sub-ambient temperatures before and between work rollers, using various cooling methods including coolant channels, chilled air, and thermally conductive guides to enhance mechanical strength and prevent sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metals with low melting temperatures are rolled at room temperature, then the rolling process is simple, but the metals lack mechanical strength and are prone to tearing and fracturing
Solution Approach 1:
The patent applies parameter changes by lowering the temperature parameter from room temperature to sub-ambient temperatures (e.g., -70°C to -196°C). This temperature parameter change fundamentally alters the mechanical properties of low-melting-point metals, transforming them from soft and ductile at room temperature to strong and brittle at sub-ambient temperatures, thereby enabling successful rolling without tearing or fracturing.
Solution Approach 2:
The patent utilizes phase transitions by cooling metals to their melting point or below, inducing a transition from a ductile state to a more brittle, strength-enhanced state. This phase transition approach allows the metals to maintain structural integrity during the rolling process while being formed into thin foils, resolving the contradiction between strength and temperature.
2Strength
If metals are cooled to sub-ambient temperatures to increase strength, then tearing and fracturing are reduced, but the complexity of the rolling system increases due to cooling subsystem requirements
Solution Approach 1:
The patent merges the cooling function with the rolling function by integrating cooling rollers that simultaneously perform both cooling and rolling operations. This consolidation eliminates the need for separate cooling subsystems and rolling mills, reducing overall system complexity while maintaining the strength benefits of sub-ambient temperature rolling.
Solution Approach 2:
The cooling rollers are designed with multi-functionality, serving both as cooling devices and as rolling elements. This universal design allows a single component to fulfill multiple functions (cooling, rolling, and forming), thereby reducing the number of components needed and simplifying the overall system architecture while achieving the desired mechanical strength improvement.
3Productivity
If metals are rolled into thinner foils to increase productivity, then output per unit time increases, but the metals are more prone to sticking to work rollers due to reduced mechanical strength
Solution Approach 1:
The patent applies parameter changes by maintaining sub-ambient temperatures throughout the rolling process, which preserves the mechanical strength of the metal even as it is reduced to thinner foil gauge. This temperature parameter control enables continuous rolling into thinner foils without the metal becoming too weak and sticking to the rollers, thereby increasing productivity while maintaining sufficient strength.
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 cooling subsystem allows metals with low melting temperatures to be rolled into thinner foils with increased strength and hardness, reducing tearing and sticking, enabling efficient foil production.
Implementation Method 1
the cooling subsystem includes cooling rollers defining channels therein configured to receive coolant to cool the cooling rollers and cool the foil in contact with the cooling rollers
Implementation Method 2
the upper guide defines perforations configured to direct chilled air through the upper guide to the metal to cool the metal with an air blanket
Data Source
AI summary
A system configured to roll a metal into a foil. The system includes work rollers spaced apart to accommodate the metal therebetween. The work rollers are configured to press against the metal to roll the metal into the foil. A cooling subsystem is spaced apart from the work rollers on a work line configured to feed the metal to the work rollers. The cooling subsystem is configured to cool the metal as the metal moves along the work line.