CoFe Laminated Core Bonding with B-Stage Adhesive Alignment
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Solution Overview
Problem
Existing methods for producing laminated cores for electric machines face challenges in achieving reliable and efficient assembly, particularly in maintaining magnetic properties and reducing eddy current losses, while also requiring precise alignment and scalable production.
Innovation Solution
A method involving the use of a B-stage adhesive applied via printing processes to soft-magnetic CoFe alloy laminations, allowing for precise alignment and bonding without heat treatment, which maintains magnetic properties and reduces eddy current losses through careful adhesive application and curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied in fluid state (A-stage) before stacking, then bonding strength is improved, but alignment precision deteriorates due to adhesive spreading and laminations sticking together
Solution Approach 1:
The adhesive is applied in the A-stage (fluid state) before stacking, allowing it to be precisely positioned on the lamination surfaces. The adhesive is then partially cured to B-stage (tack-free state) before the stacking operation, which prevents the laminations from sticking together during assembly while maintaining the bonded regions. This preliminary action of applying adhesive before stacking resolves the contradiction by enabling both strong bonding and precise alignment.
Solution Approach 2:
The adhesive undergoes a parameter change from A-stage (fluid, tacky) to B-stage (partially cured, tack-free) through controlled partial curing. This parameter change allows the adhesive to transition from a state suitable for precise application to a state suitable for stacking, resolving the contradiction between bonding strength and alignment precision during the assembly process.
2Power
If high power density is achieved through cobalt-iron alloys, then performance is improved, but manufacturing complexity increases due to precise adhesive application requirements
Solution Approach 1:
The adhesive is applied and partially cured to B-stage before stacking, which simplifies the manufacturing process for high-power-density laminated cores. This preliminary action allows for precise adhesive placement without requiring complex real-time alignment systems during stacking, as the tack-free B-stage adhesive prevents laminations from sticking together during assembly.
Solution Approach 2:
The controlled partial curing of adhesive from A-stage to B-stage creates an optimal state for manufacturing high-power-density laminated cores. This parameter change enables simple stacking operations while maintaining precise adhesive bonding, reducing manufacturing complexity despite the use of sophisticated cobalt-iron alloys.
3Reliability
If complete curing is performed before stacking, then bonding reliability is improved, but alignment flexibility is lost as laminations become fixed
Solution Approach 1:
The adhesive is applied in A-stage and partially cured to B-stage before stacking, creating a tack-free surface that allows for easy alignment and repositioning of laminations. After stacking is complete, the adhesive is then fully cured to C-stage, achieving maximum bonding reliability. This two-stage curing approach maintains alignment flexibility during assembly while ensuring bonding reliability in the final product.
4Loss of energy
If adhesive layer thickness is reduced to minimize eddy current losses, then energy efficiency is improved, but bonding strength decreases
Solution Approach 1:
The adhesive undergoes parameter changes from A-stage (fluid) through B-stage (partially cured) to C-stage (fully cured). This allows for the application of thin adhesive layers that minimize eddy current losses while the controlled partial and complete curing processes ensure adequate bonding strength is achieved, resolving the contradiction between energy efficiency and bonding strength.
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 method enables the production of laminated cores with high power density and minimal losses, ensuring precise alignment and efficient assembly, while maintaining magnetic properties and allowing for scalable production.
Implementation Method 1
separated from the solvent by the introduction of heat, for example, e.g. dried
Implementation Method 2
The stack or the adhesive in the stack is cured, thereby transferring the adhesive to a fully cured C-stage in order to bond the first and second laminations to one another
Data Source
AI summary
A method for the production of a laminated core is provided. A plurality of laminations are provided that are made of a soft-magnetic CoFe alloy and that have a first main surface and a second main surface that is located opposite the first main surface. An adhesive is applied to the first main surface of a first of the laminations by means of a printing process. The adhesive is then transferred to a partially cured B-stage. A second main surface of a second of the laminations is stacked on the B-stage adhesive, which is located on the first main surface of the first lamination, thereby forming a stack of loose laminations. The stack or the adhesive in the stack is cured, the adhesive thus being transferred to the fully cured C-stage in order to bond the first and second laminations to one another and so produce the laminated core.