Electrode Contact Pressure Control for Uniform Resistance Heating
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Solution Overview
Problem
Existing direct resistance heating methods for plate workpieces with varying width along the longitudinal direction face challenges in achieving uniform temperature distribution due to differences in segment region lengths and resistances, leading to non-uniform heat generation and temperature distribution.
Innovation Solution
A heating method and apparatus where a pair of electrodes are placed across the workpiece, with one electrode movable perpendicular to the workpiece, allowing for adjustable contact pressure and electric current distribution based on segment region lengths to ensure uniform heating, using a power supply, moving section, and control unit to manage the heating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the heating target region is divided into multiple strip-shaped segment regions with different lengths between electrodes, then the configuration of the heating apparatus can be simplified to use a single pair of electrodes, but the temperature distribution along the width direction becomes non-uniform due to different resistances in segment regions
Solution Approach 1:
The patent applies local quality by adjusting the contact pressure of electrodes at different positions along the width direction of the workpiece. Specifically, the contact pressure is made higher in segment regions with longer lengths between electrodes (higher resistance) and lower in segment regions with shorter lengths (lower resistance). This localized adjustment of contact pressure compensates for the resistance differences, ensuring uniform current density and uniform temperature distribution across all segment regions while maintaining a simple single-pair-electrode configuration
2Temperature
If multiple pairs of electrodes are provided for each segment region to achieve uniform heating, then the temperature distribution becomes uniform, but the configuration of the heating apparatus becomes complicated
Solution Approach 1:
The patent merges the function of multiple electrode pairs into a single pair of electrodes. Instead of providing separate electrode pairs for each segment region, the invention uses one pair of electrodes that spans across the entire width of the workpiece, applying different contact pressures at different positions. This merging approach achieves the uniform heating effect of multiple electrode pairs while maintaining a simple, integrated electrode structure
3Device complexity
If one electrode is moved toward the narrow end portion while applying electric current to heat the heating target region, then the configuration of the heating apparatus can be simplified, but the temperature distribution along the width direction may not be uniform due to varying segment region lengths and resistances
Solution Approach 1:
The patent applies dynamics by making the contact pressure of the electrode movable and adjustable along the width direction of the workpiece. The contact pressure is dynamically adjusted to be higher in segment regions with longer lengths between electrodes and lower in segment regions with shorter lengths. This dynamic adjustment of contact pressure during the heating process ensures uniform current density and uniform temperature distribution, achieving manufacturing precision while maintaining simplified apparatus configuration
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 enables uniform heating and temperature distribution along the workpiece, allowing for efficient manufacturing of press-molded articles with reduced energy loss and prevention of surface oxidation, while simplifying the heating apparatus configuration.
Implementation Method 1
applying electric current to the pair of electrodes, to heat the heating target region by a direct resistance heating
Data Source
AI summary
A heating method, a heating apparatus, and a method for manufacturing a press-molded article using the heating method are provided. Electrodes are placed on a workplace to extend across a heating target region in a first direction. At least one of the electrodes is moved in a second direction perpendicular to the first direction over the heating target region while applying electric current to the electrodes. A distribution of contact pressure between at least one of the electrodes and the workpiece along the first direction is adjusted, with a plurality of segment regions being defined by dividing the heating target region such that the segment regions are arranged side by side in the first direction, and in accordance with a length of each of the segment regions between the electrodes, to adjust a healing temperature of each of the segment regions of the heating target region.