Continuous Permanent Magnet Forming for Complex Magnetization
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Solution Overview
Problem
Conventional methods for manufacturing permanent magnets are inefficient in producing complex shapes and magnetization directions, leading to high costs and structural weaknesses, particularly in creating large magnet arrays and Halbach arrays, due to the difficulty in machining hard and brittle materials and overcoming magnetic forces during assembly.
Innovation Solution
A continuous 'powder-in-tube' process that allows for the production of permanent magnets with any desired shape or cross-section, enabling easier assembly and increased energy density, by heating magnetic metals under vacuum, compressing them within a non-magnetic tube, sintering, and magnetizing the alloy without the need for annealing or surface coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional methods are used to manufacture permanent magnets in simple geometrical forms, then the manufacturing process is straightforward, but the ability to produce complex shapes and magnetization directions is limited
Solution Approach 1:
The invention divides the magnet manufacturing process into separate functional steps: first forming the complex shape using flexible molding, then applying magnetic field alignment, and finally sintering. This segmentation allows complex geometries to be achieved without complicating the overall manufacturing process, as each step handles a specific aspect of the problem independently.
Solution Approach 2:
The patent applies magnetic field alignment to the powdered metal alloy before sintering, rather than attempting to machine or post-process the magnet after formation. This preliminary action of aligning magnetic domains during the forming stage enables complex magnetization directions to be built into the structure during manufacturing, eliminating the need for difficult post-manufacturing machining operations.
2Shape
If conventional machining processes are used to create complex magnet shapes, then the desired shapes can be achieved, but the cost increases and structural weaknesses are introduced
Solution Approach 1:
The patent performs preliminary shaping and magnetic alignment during the forming stage while the material is still in powder form within a flexible mold. By establishing the complex geometry and magnetic domain orientation before sintering, the need for subsequent machining operations is eliminated, preserving the inherent structural strength of the sintered material without introducing machining-induced weaknesses.
Solution Approach 2:
The invention replaces mechanical machining operations with a field-based approach where magnetic fields are used to align the powder particles during forming. This substitution of mechanical cutting/removal processes with magnetic field control allows complex shapes to be formed without compromising material integrity or introducing stress concentrations from machining.
3Productivity
If conventional methods are used to assemble large magnet arrays, then the magnets can be assembled, but the process is difficult due to magnetic forces and the time increases
Solution Approach 1:
The patent produces magnets in standardized modular forms with consistent geometries and magnetization directions, which can be segmented and assembled into larger arrays. The flexible molding process creates uniform components that are easier to handle and position during assembly, reducing the complexity of assembling large magnet arrays compared to custom-shaped magnets.
Solution Approach 2:
The invention enables precise control over magnetization direction and magnitude during the forming process, creating magnets with optimized magnetic parameters for array assembly. By controlling the magnetic field orientation during powder alignment, the resulting magnets have predictable and uniform magnetic properties that simplify the assembly process and reduce the impact of magnetic forces during handling.
4Strength
If conventional sintering and annealing processes are used, then the metal alloy is strengthened, but the manufacturing time increases
Solution Approach 1:
The patent extracts or eliminates the separate annealing step from the conventional manufacturing process. By using flexible molding with magnetic field alignment followed by direct sintering, the invention achieves both structural strength and magnetic properties without requiring the additional time-consuming annealing treatment, thereby reducing total manufacturing time while maintaining alloy 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 cost-effective, robust, and easily assembled permanent magnets that can be produced in complex shapes, such as Halbach arrays, with higher energy density and reduced assembly challenges, facilitating applications in energy, medical, and transportation industries.
Implementation Method 1
heating magnetic metals to their melting point under vacuum to create a metal alloy
Implementation Method 2
A magnetic field is applied to the powder to line up the powder particles
Implementation Method 3
compressing them within a non-magnetic tube
Implementation Method 4
the powdered metal alloy is heated. The metal alloy is removed from the die and placed in an oven for sintering, which fuses the powder into a solid piece
Implementation Method 5
the alloy is placed between the poles of a powerful electromagnet and oriented in the desired direction of magnetization. The electromagnet is then energized for a period of time. The magnetic force aligns the groups of atoms, or magnetic domains, within the material to transform the alloy into a strong permanent magnet
Data Source
AI summary
A continuous method of manufacturing permanent magnets and the permanent magnets created thereby. A fine powder is created from a combination of magnetic metals. The powder (a metal alloy) is placed in a non-magnetic container of any desired shape which could be, for example, a tube. The metal alloy and tube are swaged while a magnetic field is applied. Once swaging is complete, the metal alloy and tube are sintered and then cooled. Instead of sintering, a bonding agent can mixed into the powder. Following cooling, the metal alloy is magnetized by placing it between poles of powerful electromagnets with the desired field direction. The process of the invention enables mass-produced, cost-effective PM products, which are more robust, easily assembled into products, enables new “wire like” shapes with arbitrary magnetization direction. The process enables mass production of permanent magnets of any desired cross section, produces permanent magnets continuously that may be cut to any length, and may, in an embodiment, result in directional magnets.