Magnetic Sheet Stack Optimization via Topography Measurement

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Solution Overview

Problem

Magnetic sheet stacks for electrical machines, such as electric motors and generators, face issues with mechanical tension and reduced material filling due to irregular thickness and adhesion problems in sieve or stencil printing processes, leading to delamination and compromised mechanical strength.

Innovation Solution

The solution involves using a screen printing process to create magnetic plates, measuring their topography, and calculating an optimized stacking sequence to minimize mechanical forces and maximize material filling, with optional rotation of plates and the use of compensation elements via additive manufacturing to ensure high filling and reduced resin usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sieve or stencil printing process is used to manufacture magnetic plates, then production flexibility and design freedom are improved, but thickness precision and uniformity deteriorate

Engineering Contradiction:
Improveproduction flexibilityVSAvoidthickness precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent measures the topography of each magnetic plate before stacking and uses this data to pre-calculate an optimized stacking sequence. This preliminary measurement and planning action compensates for thickness variations before the plates are assembled, allowing the use of flexible printing processes while achieving precise final stack dimensions.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If mechanical pressing is applied to minimize manufacturing irregularities in the stack, then filling degree is improved, but mechanical tensions and delamination cracks increase

Engineering Contradiction:
Improvefilling degreeVSAvoidmechanical strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

By measuring topography beforehand and calculating the optimal stacking sequence in advance, the system compensates for thickness variations through intelligent arrangement rather than forceful compression. This preliminary planning eliminates the need for aggressive mechanical pressing, achieving high filling degrees while preserving plate integrity and avoiding delamination.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If additional adhesive is used to compensate for areas that cannot be compensated by mechanical pressing, then filling degree is improved, but mechanical tensions and delamination risk increase

Engineering Contradiction:
Improvefilling degreeVSAvoiddelamination resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The topography measurement and stacking sequence calculation performed before assembly enables compensation of thickness variations through optimal arrangement. This preliminary action reduces or eliminates the need for additional adhesive materials, achieving high filling degrees while maintaining reliable bonding and preventing delamination cracks.

Inventive Principle:
Principle #10Preliminary action

4Device complexity

If indiscriminate stacking of magnetic plates is performed, then assembly complexity is reduced, but filling degree of the magnetic sheet stack deteriorates

Engineering Contradiction:
Improveassembly complexityVSAvoidfilling degree
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The system uses feedback from topography measurements of individual plates to dynamically calculate and determine the optimal stacking sequence. This feedback-driven approach optimizes the filling degree by accounting for actual plate variations, while the automated calculation process keeps assembly complexity manageable through systematic rather than random stacking.

Inventive Principle:
Principle #23Feedback

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 enhances the mechanical strength and magnetic material filling of the sheet stack, improving resistance to bending and centripetal forces at high rotational speeds while minimizing additional filling materials.

Implementation Method 1

a sieve or stencil printing process is characterized by increased thick-tolerances compared to sheets that have been created by rolling technology

Methodology Applied
Scientific EffectScreen printing:

Implementation Method 2

the resulting green body is transferred to a metallic structured sheet through thermal treatment, in particular reduction and sintering

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP4060882A1Magnetic sheet stack, method for producing same and electrical machine
Publication Date: 2022.09.21 SIEMENS AG
  • EP4060882A1 patent drawingFigure 1
  • EP4060882A1 patent drawingFigure 2~3
  • EP4060882A1 patent drawing

AI summary

The invention relates to a method for producing a stack of magnetic sheets (2) for an electric machine comprising the following steps: - Production of magnetic sheets (6) using a screen printing process, - Measurement of the topography of the magnetic sheets to be stacked, - Input of topography data into a computer (8), - Calculation of a stacking sequence (10) in which a maximum fill level of the magnetic sheet stack (2) is achieved, - Assembly of the magnetic sheet stack according to the result of the calculation.