One-step forming process for sintered NdFeB permanent magnet of motor and mould thereof

Abstract

The invention discloses a one-step forming process for a sintered NdFeB permanent magnet of a motor and a mould thereof. The one-step forming process comprises the following steps of preparing raw materials, smelting, casting, pulverizing, performing magnetic orientation press molding to the raw materials into a tile magnet, sintering, performing backfire and performing surface processing to the material into a finished product. The mould comprises an upper pressing head, a lower pressing head and a cavity die body, wherein the lower pressing head is connected with a hydraulic arm, a cavity of the cavity die body is a tile cavity, the upper pressing head is connected with a demolding micro-pressure protecting device, and the demolding micro-pressure protecting device is linked with a hydraulic machine. The invention has the advantages of saving the procedures of processing a square magnet into the tile magnet to achieve the aims of time-saving, money-saving and labor-saving; and changing the prior process of making the tilt material by using the square material to achieve the efficacy of processing corner-free materials and reducing the loss of powder quantity. The mould improves the designs and the process manufacture of a cavity die inner cavity and the upper and lower pressing heads. A forming bidirectional pressing special device and the demolding micro-pressure protecting special device are adopted to ensure the even density of a forming blank and reduce the phenomena of hidden cracking, edge breaking, corner defect, and the like caused by the density difference.

Description

technical field [0001] The invention relates to a one-time molding process and mold for a sintered NdFeB permanent magnet used in a motor. Background technique [0002] NdFeB permanent magnet materials have been widely used in many fields such as electronics, computers, automobiles, machinery, energy, and medical equipment due to their high magnetic energy, high coercive force, and high operating temperature. The sintered NdFeB permanent magnet tiles used for motors occupy an important position. The manufacturing process of the existing sintered NdFeB series permanent magnet materials is as follows: raw material preparation → smelting → ingot casting → crushing powder → magnetic field orientation pressing into a square Magnet→sintering→tempering→machining into a tile-shaped magnet→surface treatment→testing. Since this process does not have a micro-pressure protection device for demoulding, it mainly relies on the pressure of the upper cylinder of the press to complete the p...

AI Technical Summary

Problems solved by technology

Since this process does not have a micro-pressure protection device for demoulding, it mainly relies on the pressure of the upper cylinder of the press to complete the pressure maintaining action. Due to the high pressure of the press, which can reach 63 tons, it will be affected by factors such as oil volume and temperature, which will cause insufficient oil pressure. Stable, the pressure of the upper cylinder changes greatly, resulting in a low pass rate of product cracking

The magnet mold for magnetic field orientation pressing is square, so when the pressed magnet is applied to the motor, the square magnet must be machined into a tile-shaped magnet, which not only increases the difficulty of the manufacturing process, but also takes time and labor. money, so improving the structure of the mold has become a very necessary topic

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