Magnetic Sheet Stack Sintering to Cut Stamping Waste
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Solution Overview
Problem
Conventional methods for manufacturing magnetic sheets result in significant stamping waste, are economically and ecologically inefficient, and require complex additional processes for insulation, especially in the production of soft magnetic laminations.
Innovation Solution
A method involving the production of a slip film with alternating soft magnetic and electrically insulating layers, which are folded into a stack and sintered to form a near-net-shape magnetic sheet stack, allowing for easy separation and recycling of residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional stamped magnetic sheets are used, then manufacturing is simple, but stamping waste amounts to approximately 50% of total volume and requires complex remelting processes
Solution Approach 1:
The magnetic sheets are pre-cut to final shape during the slip casting process before sintering, achieving near-net-shape manufacturing. This preliminary shaping eliminates the need for subsequent stamping and complex remelting operations, directly reducing material waste and process complexity
Solution Approach 2:
The invention changes the manufacturing approach from mechanical stamping of solid metal to slip casting of green bodies followed by sintering. This parameter change in the manufacturing process enables near-net-shape production with minimal waste and simpler recycling
2Manufacturing precision
If screen-printed magnetic sheets are used, then very thin magnetic sheets are achieved with reduced eddy current losses, but the process is cost-intensive and requires additional insulation steps after sintering
Solution Approach 1:
The electrically insulating layer is applied to the magnetic powder layer before sintering, rather than after. This preliminary insulation action eliminates the need for additional post-sintering insulation steps, reducing process complexity while maintaining the thin sheet thickness advantage
Solution Approach 2:
The insulation layer application is merged with the green body formation process, combining two functions (insulation and shaping) into a single integrated step before sintering, thereby simplifying the overall manufacturing process
3Reliability
If insulation is applied after thermal sintering, then electrical insulation is achieved, but the process becomes technically complex and costly
Solution Approach 1:
The electrically insulating layer is applied to the green body before sintering, ensuring insulation is established in advance. This preliminary action guarantees electrical insulation reliability while avoiding the technical complexity of post-sintering insulation processes
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
Achieves thinner magnetic sheet thickness, reduced process complexity, and improved recyclability of die-cutting residues, with economic benefits over conventional and screen-printed methods.
Implementation Method 1
drying of the soft magnetic layer
Implementation Method 2
sintering of the magnetic sheet stack to form a near-net-shape magnetic sheet stack
Data Source
Figure 1
Figure 2a~2c
Figure 3~5
AI summary
The invention relates to a method for producing a stack of magnetic sheets (2), comprising the following steps: - producing a magnetic sheet (12) wherein a slurry 6 comprising soft magnetic particles mixed with a binder is first formed into a first, soft magnetic layer (8), - drying the soft magnetic layer (8), - applying a second, electrically insulating layer (10) to the soft magnetic layer (8) so that a magnetic sheet (12) is formed, - fanning the magnetic sheet (12) into a stack of sheets (14) such that two soft magnetic layers (8) and two electrically insulating layers (10) alternately lie on top of each other in the stack of sheets (14), - separating a stack of magnetic sheets (2-1) in the green state from the folded stack of sheets (14), - debinding the stack of magnetic sheets (2-1), - sintering the stack of magnetic sheets (2-1) to form a near-net-shape stack of magnetic sheets (2-2).so that - two superimposed identical layers (8, 10), two soft magnetic layers (8) and two electrically insulating layers (10) in the sintered state of the magnetic sheet stack (2-2) each form a magnetic sheet (16).