NdFeB Hot-Deformation Punch Structure for Crack Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The prolonged exposure of NdFeB magnets to high temperatures during the hot-pressing and hot-deformation process leads to cracks and degradation of magnetic properties in existing manufacturing technologies.
Innovation Solution
A magnetic powder hot-pressing and hot-deformation apparatus and method that divides the process into pre-deformation at a low temperature and final deformation at a high temperature, using a specific apparatus configuration with movable inner and outer punches and sleeves, and controlled pressure and temperature conditions to minimize exposure to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the compact from hot-pressing is directly subjected to high-temperature hot-deformation, then the deformation process can be completed, but cracks form and magnetic properties degrade
Solution Approach 1:
The patent divides the hot-deformation process into two distinct stages: a first hot-deformation process at a lower temperature range (600-800°C) and a second hot-deformation process at a higher temperature range (800-1000°C). This segmentation allows the compact to undergo initial deformation at moderate temperatures, then final deformation at elevated temperatures, thereby avoiding prolonged exposure to high temperatures that cause cracking while still achieving the desired magnetic properties.
2Manufacturing precision
If high temperature is applied for extended duration, then deformation can be achieved, but crack formation increases
Solution Approach 1:
The patent performs the first hot-deformation process before the second hot-deformation process. During this preliminary action, the compact is deformed at a lower temperature (600-800°C) to establish the basic shape and reduce internal stresses. This preliminary deformation prepares the material for the subsequent high-temperature deformation, reducing the risk of crack formation during the final shaping stage.
3Productivity
If prolonged high-temperature exposure is used, then complete deformation is achieved, but magnetic properties deteriorate
Solution Approach 1:
The patent employs periodic action by implementing two distinct hot-deformation processes with different temperature ranges and duration characteristics. The first process operates at 600-800°C for an initial period, followed by the second process at 800-1000°C for a shorter duration. This periodic temperature variation achieves complete deformation while limiting total high-temperature exposure time, thereby preserving magnetic properties.
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
The method reduces the probability of crack formation and enhances the magnetic properties of NdFeB magnets by shortening high-temperature exposure, resulting in improved magnetic performance.
Implementation Method 1
moving the lower inner punch upward to apply pressure to a NdFeB magnetic powder so as to hot-press it
Implementation Method 2
moving the upper inner punch downward to apply pressure to the NdFeB hot-pressed compact so as to pre-deform it
Implementation Method 3
moving the upper punch assembly and the lower punch assembly toward the pre-deformed compact to subject the pre-deformed compact to final deformation
Data Source
AI summary
The present disclosure provides a magnetic powder hot-pressing and hot-deformation apparatus and a hot-pressing and hot-deformation method. The magnetic powder hot-pressing and hot-deformation apparatus comprises a female die, an upper punch assembly, and a lower punch assembly. The upper punch assembly comprises an upper inner punch and an upper outer sleeve. At least a portion of the upper inner punch is inserted into the upper outer sleeve cavity, and the upper inner punch is configured to be movable vertically relative to the upper outer sleeve. The lower punch assembly comprises a lower inner punch and a lower outer sleeve. At least a portion of the lower inner punch is inserted into the lower outer sleeve cavity, and the lower inner punch is configured to be movable vertically relative to the lower outer sleeve. The diameter of the lower outer sleeve cavity is smaller than the diameter of the upper outer sleeve cavity. The magnetic powder hot-pressing and hot-deformation apparatus can improve the magnetic properties of NdFeB magnets.