Permanent Magnet Sintering With Conductive-Insulating Die Control
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Solution Overview
Problem
Conventional methods for manufacturing permanent magnets, such as die cutting and machining, are costly and inefficient, particularly when aiming for complex shapes and high-density materials.
Innovation Solution
The use of field-assisted sintering techniques, specifically spark plasma sintering, in conjunction with a die assembly having conductive and insulating surface portions, allows for the creation of permanent magnets with high-density and low-density portions, optimizing magnetic, electric, and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional die cutting and machining methods are used to manufacture permanent magnets, then manufacturing precision and material density can be achieved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent replaces conventional mechanical die cutting and machining methods with field-assisted sintering that uses electrical fields and plasma to consolidate magnetic powder directly into high-density magnets. This substitution of mechanical processes with field-based processes achieves high density while dramatically improving manufacturing efficiency and reducing costs
Solution Approach 2:
The patent utilizes controlled parameter changes in the sintering process, specifically varying electrical current density, temperature, and atmospheric conditions during field-assisted sintering to achieve optimal magnet density and properties without requiring subsequent machining operations
2Ease of manufacture
If uniform electrical current is applied during sintering, then the process is simple, but magnets with complex shapes and tailored density distributions cannot be produced
Solution Approach 1:
The patent applies local quality by using die assemblies with conductive and insulating surface portions that create non-uniform electrical current distribution during sintering. This enables different regions of the magnetic powder to experience different current densities, allowing production of magnets with complex shapes and tailored density distributions while maintaining process simplicity
Solution Approach 2:
The die assembly is segmented into conductive and insulating surface portions, allowing independent control of electrical current pathways. This segmentation enables versatile magnet shape creation by strategically placing conductive regions to guide current flow patterns during field-assisted sintering
3Reliability
If high-density magnets are produced throughout the entire magnet body, then magnetic performance is maximized, but manufacturing cost and processing complexity increase for complex shapes
Solution Approach 1:
The patent applies local quality by creating magnets with spatially varying density distributions through controlled non-uniform current application during sintering. High-density regions are formed where high current density is applied, while lower-density regions occur where insulating die portions reduce current flow, achieving optimized magnetic performance without uniform high-density manufacturing complexity
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 efficient production of magnets with complex shapes and tailored properties, reducing manufacturing costs and enhancing efficiency while maintaining or improving magnetic performance.
Implementation Method 1
The electrical current may be applied through the first die such that the first surface portion applies a greater current to the magnetic powder mixture than the second surface portion to form a sintered magnet having a high-density portion adjacent the first surface portion
Implementation Method 2
The use of field-assisted sintering techniques, specifically spark plasma sintering
Implementation Method 3
the second surface portion may be non-conductive
Data Source
AI summary
Magnets having various portions of different densities and resistivities are disclosed. In a refinement, the various portions may have the same composition but different physical structures. Unique dies may be used to during processing, such as during sintering to manufacture the magnets. The die may include conductive and non-conductive surfaces that contact the green magnetic powder mixture during sintering such that the electrical current applied to the magnetic powder mixture is managed by the conductive and non-conductive surfaces to provide unique and complex magnets. Methods of manufacturing the magnets with the dies such as field assisted sintering, i.e., spark plasma sintering, are also disclosed.