Dust Core Molding with Temperature-Zoned Die Heating
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Solution Overview
Problem
Existing methods for manufacturing dust cores result in cracks and bulges, and the cores do not possess desired electromagnetic characteristics due to uniform temperature distribution in the metal die, leading to hardening and crystallization issues.
Innovation Solution
The method involves using a metal die with a low-temperature portion and a high-temperature portion, where the temperature difference is at least 10°C, to control the hardening and crystallization of magnetic particles, ensuring air and gas release and preventing overheating, thereby producing a dust core with no cracks or bulges and desired electromagnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If uniform temperature distribution is applied throughout the metal die, then binder hardening starts uniformly at the outer part, but air and gas release is prevented causing cracks and bulges
Solution Approach 1:
The patent applies local quality by creating different temperature zones within the metal die. Specifically, the die includes a first region with a first temperature and a second region with a second temperature that is lower than the first temperature by 10°C or more. This temperature gradient causes the binder to harden at different rates in different regions, allowing air and gas to escape from regions where the binder has not yet hardened, thereby preventing cracks and bulges while maintaining controlled hardening.
2Stability of the object's composition
If uniform temperature distribution is applied throughout the metal die, then crystallization starts uniformly at the outer part, but heat transmission to the center produces Fe-B compound phase degrading electromagnetic characteristics
Solution Approach 1:
The patent applies local quality by creating different temperature zones within the metal die. Specifically, the die includes a first region with a first temperature and a second region with a second temperature that is lower than the first temperature by 10°C or more. This temperature gradient causes magnetic particles in different regions to crystallize at different rates, preventing excessive heat accumulation in the center that would produce Fe-B compound phase and degrade electromagnetic characteristics.
3Strength
If thermosetting resin binder is used, then binder hardening provides structural stability, but hardened resin at outer part prevents air and gas release
Solution Approach 1:
The patent applies local quality by creating different temperature zones within the metal die. The temperature gradient causes the thermosetting resin binder to harden at different rates in different regions. In regions with lower temperature, the binder hardens more slowly, allowing air and gas to escape before the binder sets. This prevents entrapment of air and gas while still achieving the structural stability provided by binder hardening.
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 manufacturing method produces a dust core with no cracks or bulges and maintains desired electromagnetic characteristics by controlling temperature distribution, ensuring proper binder hardening and magnetic particle crystallization.
Implementation Method 1
the metal die is provided with a low-temperature portion and a high-temperature portion; and a temperature of the low-temperature portion is less than a temperature of the high-temperature portion by 10° C. or more
Implementation Method 2
crystallization of magnetic particles wholly starts at an outer part of a dust core, which is brought into contact with the metal die, if the magnetic particles are crystallized by heat treatment
Data Source
AI summary
A dust core is manufactured by compacting magnetic particles in a metal die while heating the magnetic particles at a predetermined temperature in the metal die. At least some of the magnetic particles are coated with coating material. The metal die comprises a die, an upper punch and a lower punch. The upper punch is positioned above the lower punch in an up-down direction. The metal die is provided with a low-temperature portion and a high-temperature portion. A temperature of the low-temperature portion is less than a temperature of the high-temperature portion by 10° C. or more.