Applicator for Grain Boundary Diffusion in NdFeB Magnets
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Solution Overview
Problem
Existing methods for applying RH powder to sintered compacts during the grain boundary diffusion process in NdFeB system magnet production face challenges in uniformly applying the correct amount and pattern, leading to inefficiencies and increased costs due to dispersion and difficulty in simultaneous application to multiple compacts.
Innovation Solution
An applicator system utilizing a screen with a passage section corresponding to the desired pattern, allowing for precise and uniform application of RH powder slurry to sintered compacts, which can be reused and easily automated for efficient mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If RH powder is applied to increase coercive force, then magnetic resistance improves, but manufacturing cost increases due to RH being expensive
Solution Approach 1:
The patent applies RH powder locally to specific regions of the sintered compact where coercive force enhancement is most needed, rather than uniformly across the entire surface. This is achieved through a barrel painting mechanism that selectively deposits powder in target areas, reducing overall RH consumption while maintaining necessary magnetic performance.
Solution Approach 2:
The patent uses a thin layer of RH powder applied through a screen with specific mesh patterns, providing just enough coating to achieve the desired coercive force increase without excessive material usage. The screen structure controls the deposition thickness to be minimal yet effective.
2Strength
If RH powder is applied uniformly to ensure adequate coating, then coercive force increases, but RH powder waste increases due to dispersion
Solution Approach 1:
The patent extracts only the necessary amount of RH powder through a screen structure that filters and controls powder deposition. The screen with its mesh pattern allows precise extraction and placement of powder particles only where needed, preventing dispersion and waste of excess powder.
Solution Approach 2:
The screen acts as an intermediary between the RH powder source and the sintered compact surface. It mediates the deposition process by controlling powder flow through its mesh structure, ensuring uniform distribution without dispersion and enabling complete utilization of the applied powder.
3Ease of operation
If manual application method is used to apply RH powder, then flexibility is maintained, but productivity decreases due to inability to process multiple compacts simultaneously
Solution Approach 1:
The patent merges multiple sintered compacts into a single assembly held by a holder, allowing simultaneous application of RH powder to all compacts at once through the barrel painting mechanism. This maintains operational simplicity while dramatically increasing productivity by processing multiple pieces in one operation.
Solution Approach 2:
The barrel painting mechanism serves multiple functions: it can apply powder to single or multiple compacts, control deposition thickness, and adjust application patterns by changing screen configurations. This multi-functionality maintains operational flexibility while enabling high-volume processing.
4Strength
If thick layer of RH powder is applied to ensure sufficient diffusion, then coercive force increases, but RH powder consumption increases
Solution Approach 1:
The patent employs a thin film approach using a screen with controlled mesh size that deposits a uniform thin layer of RH powder. This thin film is sufficient for diffusion during heat treatment while minimizing material consumption, as the screen structure prevents excessive powder accumulation.
Solution Approach 2:
The patent controls the deposition parameters through screen mesh size and barrel rotation speed to achieve optimal powder thickness. By adjusting these parameters, the system produces just the right amount of coating needed for effective diffusion without excess material usage.
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
Enables uniform and controlled application of RH powder, reducing waste and costs by allowing precise adjustment of thickness and pattern, facilitating high coercive force production without excessive RH usage, and supporting mass production and automation.
Implementation Method 1
a screen (21) having a passage section (211) which allows the coating material to pass therethrough
Implementation Method 2
the sintered body is heated to the temperature at which RH diffuses... RH penetrates into the sintered compact through the grain boundaries of the Nd2Fe14B crystal grains which exist in the sintered compact, so that RH is diffused on the surface of the crystal grains
Data Source
AI summary
An applicator for grain boundary diffusion process that uniformly applies an RH powder without excess or deficiency onto a predetermined surface of a sintered compact with a given thickness and in a given pattern, the applicator being automated and performed on many sintered compacts during the production of a NdFeB system sintered magnet. The applicator includes a work loader and a print head, located above the work loader. The work loader includes: a laterally movable base; a lift being vertically movable with respect to the base; a frame that is attachable to and detachable from the lift; a tray that is attachable to and detachable from the frame; a supporter provided on the upper surface of the tray; and a vertically movable magnetic clamp. The print head includes: a screen having a passage section; and a movable squeegee and a backward scraper that maintains contact with the upper screen surface.