Laser-Cut Laminated Iron Core for Lower Iron Loss
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Solution Overview
Problem
Existing methods for manufacturing laminated cores for transformers and rotary machines face challenges in achieving consistent iron loss properties due to issues like short-circuiting, crack formation in insulating coatings, and high magnetic reluctance at butted portions, leading to variations in iron loss.
Innovation Solution
The method involves processing electrical steel sheets with a pulsed or continuous laser to control crack formation, shear droop, surface roughness, and insulating coating presence, utilizing a shock wave mechanism to inhibit stress and reduce voids, thereby improving iron loss properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating varnish is coated on the surface of each thin plate before stacking, then insulation between plates is improved, but production time increases and manufacturing efficiency decreases
Solution Approach 1:
The insulating varnish is pre-coated on the thin plates during the coil winding process, before the plates are stacked to form the laminated core. This preliminary action ensures insulation is already in place, eliminating the need for separate post-stack coating operations and reducing total production time.
Solution Approach 2:
The patent combines multiple functions into the coil winding process: the insulating varnish coating and the plate stacking are integrated into a single continuous operation. The varnish is applied and the plates are stacked in one workflow, eliminating separate manufacturing steps and improving efficiency.
2Reliability
If insulating varnish is coated after stacking the thin plates, then insulation is ensured, but production time increases and efficiency decreases
Solution Approach 1:
Instead of coating varnish after stacking (post-stack), the patent applies the insulating varnish before stacking (pre-stack). This preliminary coating ensures insulation is established during the winding process itself, eliminating the need for time-consuming post-stack coating operations.
3Reliability
If manual coating of insulating varnish is performed, then insulation quality can be controlled, but labor costs increase and production efficiency decreases
Solution Approach 1:
The patent replaces manual mechanical coating operations with an automated coating mechanism integrated into the coil winding machine. This mechanical substitution maintains consistent insulation quality through controlled application while dramatically improving production efficiency by eliminating manual labor bottlenecks.
Solution Approach 2:
The coil winding process itself provides the insulation function through integrated varnish coating. The system serves its own insulation needs during the winding operation, eliminating the need for separate manual coating operations and reducing labor requirements.
4Reliability
If insulating varnish coating process is added to ensure insulation, then reliability improves, but the number of manufacturing steps increases
Solution Approach 1:
The patent merges the insulating varnish coating step with the coil winding and plate stacking operations into a single integrated process. The varnish is applied during winding, and the plates are stacked immediately afterward in continuous operation, reducing the number of discrete manufacturing steps while ensuring insulation quality.
Solution Approach 2:
The coil winding process is given multiple functions: it performs the winding operation, applies the insulating varnish coating, and prepares the plates for stacking. This multi-functionality eliminates the need for separate dedicated coating equipment and steps, simplifying the overall manufacturing process.
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 effectively reduces iron loss by controlling the formation of cracks, shear droop, and surface roughness, enhancing the magnetic flux flow and achieving better iron loss properties in laminated cores.
Implementation Method 1
a resin layer which has been UV-cured is formed on the surface of the laminated iron core
Data Source
Figure 1~2
Figure 3~4
AI summary
Methods for manufacturing a laminated core that enable good iron loss properties to be achieved are provided. A method for manufacturing a laminated core of the present invention includes processing an electrical steel sheet into pieces of the electrical steel sheet that have a predetermined shape, by using a pulsed laser having a beam diameter of 200 um or less and a pulse width of a nanosecond or more or by using a continuous laser having a beam diameter of 200 um or less, the electrical steel sheet including an insulating coating on a surface, the insulating coating having a roughness factor of a surface of 2.0 or greater; and stacking the pieces of the electrical steel sheet resulting from the processing. Another method for manufacturing a laminated core of the present invention includes processing an electrical steel sheet into pieces of the electrical steel sheet that have a predetermined shape, the processing being performed by using a picosecond pulsed laser or a femtosecond pulsed laser or being performed in water or in a state in which a water film is present on a surface of the electrical steel sheet by using a pulsed laser having a pulse width of a nanosecond or more or by using a continuous laser, the electrical steel sheet including an insulating coating on the surface; and stacking the pieces of the electrical steel sheet resulting from the processing.