Linear Groove Patterning for Grain-Oriented Electrical Steel
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Solution Overview
Problem
Existing methods for forming grooves on grain-oriented electrical steel sheets to reduce iron loss and improve magnetic flux density face challenges such as variations in groove shape leading to magnetic property deterioration, increased groove volume affecting permeability, and production inefficiencies, particularly with methods like electroetching and laser processing.
Innovation Solution
A method involving the use of an electroetching process combined with a resist removing technique, where laser beams from multiple devices form continuous grooves with discontinuous center lines, optimizing groove patterns to enhance iron loss reduction and magnetic flux density by controlling groove shape and atmosphere gas flow during annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If grooves are formed deeper to improve iron loss reduction effect, then magnetic domain refining effect is enhanced, but groove volume increases and magnetic permeability deteriorates
Solution Approach 1:
The patent applies local quality by creating discontinuous center lines in the grooves, where the groove shape varies locally to optimize magnetic domain refining effect while controlling overall groove volume. This local variation in groove geometry allows different sections to serve different functions in reducing iron loss without excessively increasing total groove volume
Solution Approach 2:
The patent utilizes curvature by forming grooves with discontinuous center lines rather than straight continuous lines. This curved/discontinuous geometry optimizes the magnetic domain refining effect at the groove boundaries while controlling the volume occupied by the grooves, thereby improving iron loss reduction without excessive permeability deterioration
2Adaptability or versatility
If groove shape varies due to resist pattern variation, then production flexibility is improved, but magnetic properties deteriorate due to inconsistent groove formation
Solution Approach 1:
The patent applies preliminary action by pre-defining the groove pattern design with discontinuous center lines before production. This predetermined optimal geometry serves as a template that guides the groove formation process, ensuring consistent magnetic property improvement while allowing production flexibility through the established design framework
Solution Approach 2:
The patent utilizes parameter changes by optimizing specific groove parameters such as the discontinuous center line configuration, groove width, and depth. By carefully controlling these geometric parameters, the patent achieves reliable magnetic property improvement while maintaining production flexibility through parameter optimization rather than rigid process constraints
3Device complexity
If continuous grooves are formed to simplify the process, then manufacturing complexity is reduced, but magnetic permeability deteriorates due to increased groove volume
Solution Approach 1:
The patent applies segmentation by dividing the continuous groove into sections with discontinuous center lines. This segmentation reduces the effective groove volume while maintaining the groove formation process simplicity, thereby preserving magnetic permeability without significantly increasing process complexity
Solution Approach 2:
The patent uses curvature through discontinuous center lines to optimize groove geometry. This curved/discontinuous design reduces groove volume compared to straight continuous grooves, maintaining magnetic permeability while keeping the manufacturing process relatively simple through a single groove formation step
4Loss of energy
If groove depth is increased to enhance magnetic domain refining, then iron loss reduction is improved, but production efficiency decreases due to longer processing time
Solution Approach 1:
The patent applies local quality by concentrating the magnetic domain refining effect at the discontinuous center line regions rather than uniformly throughout the entire groove. This localized effect achieves effective iron loss reduction with shallower overall groove depth, thereby reducing processing time and improving production efficiency
Solution Approach 2:
The patent utilizes curvature through discontinuous center lines to optimize the distribution of groove depth. This geometric configuration concentrates the effective groove volume at critical locations for magnetic domain refining, achieving iron loss reduction with reduced total groove volume and shorter processing time
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 method achieves improved iron loss and magnetic flux density in grain-oriented electrical steel sheets by forming grooves with controlled discontinuities, reducing groove volume and promoting dense forsterite coating, thus enhancing the steel's magnetic properties and production efficiency.
Implementation Method 1
a laser method (Patent Literature 3), in which the steel sheet is locally melted and evaporated by using a high-power laser
Implementation Method 2
an electroetching method (Patent Literature 2), in which grooves are formed on the steel sheet surface by performing electroetching
Implementation Method 3
a method that grooves are formed or local strain is applied after a steel sheet has been subjected to finish annealing
Data Source
AI summary
A linear groove formation method including forming a coated resist on a surface of a steel sheet, irradiating two or more laser beams onto the surface of the steel sheet while scanning the laser beams in a direction intersecting the rolling direction of the steel sheet cyclically in a rolling direction of the steel sheet, and forming linear grooves by etching portions of the steel sheet. In the laser irradiating process, the coated resist is removed continuously in a sheet transverse direction of the steel sheet by using the laser beams irradiated from respective ones of two or more laser irradiation devices arranged in the sheet transverse direction, and the laser beams are irradiated by shifting centers of two of the laser beams irradiated from two of the laser two of the laser irradiation devices adjacent to each other in the sheet transverse direction.