The company's current production process of sintered NdFeB permanent magnet materials can be divided into two parts: the blank process (also known as the "front process" in the industry) and the finished product process (also known as the "post process" in the industry): the blank process is the praseodymium Neodymium metal, pure iron, ferroboron and other raw materials are used to make NdFeB blanks; the finished product process is to process NdFeB blanks by mechanical processing and surface treatment to obtain NdFeB magnets. The specific production process flow chart is as follows:
Mix solid raw materials such as praseodymium and neodymium metals, pure iron, and ferroboron in proportion.
The mixed raw materials are smelted through the smelting furnace, and then the quick-setting thin strip alloy sheet is formed by stripping.
The rapid-setting thin strip alloy flakes are crushed into coarse alloy powder through the secondary crushing furnace, and then fine alloy powder is made into alloy powder through jet milling.
Under the protection of nitrogen, the powder is made into a compact by pressing.
The compact is heated to a high temperature in a sintering furnace in a vacuum environment and then subjected to aging heat treatment to form a NdFeB blank.
Use professional equipment to process the blank according to the specific requirements of the order for shape and size, including grinding, wire cutting, slicing, punching, etc.
Cover the surface of the magnet with heavy rare earth metal or compound, and diffuse the heavy rare earth element into the interior of the sintered NdFeB magnet by heating
In order to meet the performance requirements of wear resistance and corrosion resistance, mechanical grinding and electrochemical treatment are carried out on the surface of the magnet.
According to the needs of the order, magnetize the magnet in the magnetic field using a magnetizer.
According to the requirements of the order, the magnetic properties, appearance, size, corrosion resistance and other properties of the magnets are inspected, and the packaging and storage can only be carried out after passing the inspection.
The company applies technologies such as casting columnar crystal growth control technology, grain refinement and micro-optimization technology, etc., and is committed to improving the consistency of powder and giving full play to the performance potential of rare earth. By improving the smelting microstructure, applying fine-grain technology, and optimizing the mixing process, etc., significantly improving the performance of NdFeB magnets.
The company has applied and improved low-oxygen magnet preparation technology and cold isostatic pressing technology, so that NdFeB magnets are in a low-oxygen state during the pressing process, and the preparation of molding blanks is continuously optimized, which effectively reduces the loss of rare earth. The application of low-temperature sintering heat treatment technology has further improved the sintering process. Adjusting the temperature to a suitable state can give full play to the performance of the formula. The representative products are high-performance N55 magnets prepared by low-oxygen technology and N38UH magnets produced by near-net molding technology.
In order to pursue the accurate precision of customer customization, the company applies high-performance ultra-thin small special-shaped permanent magnet preparation technology to carry out high-efficiency and low-loss precision machining of NdFeB blanks, breaking through the technical bottleneck of high-performance thin and small magnet processing difficulty, and Strictly control product appearance defects through intelligent image appearance automatic inspection technology to improve inspection efficiency and accuracy.
The company's current production process of permanent ferrite magnets is as follows: the purchased pre-fired materials are mixed according to their own formula and ingredients, and after being ball milled by a ball mill, ferrite is produced through steps such as precipitation, wet pressing, sintering, and grinding. Body magnetic tiles, ferrite magnets and other finished products. The specific production process flow chart is as follows:
The strontium ferrite calcined material (the main component is SrFe12O19) is mixed with calcium carbonate, silicon dioxide, strontium carbonate, lanthanum oxide, cobalt oxide and other ingredients according to the formula ratio.
The raw materials are added with water and pulverized by a ball mill to form a slurry, which is placed in a sedimentation tower for precipitation.
The dehydrated material formed by precipitation is made into a green body through an automatic press in a normal air environment.
The raw body is sintered at high temperature into a mature body through a wet-pressed magnetic tile electric-fired roller kiln or a wet-pressed magnetic steel gas-fired roller kiln.
The cooked blank is processed by a fully automatic grinding machine processing line to form a finished product.
The magnetic properties, appearance, size and other indicators of the magnets are inspected, packed and put into storage.
The company has applied and improved a number of advanced technologies in the industry, such as high-performance ferrite slurry stabilization technology and secondary ball milling batching technology, which has solved the quantitative problem of material added in the preparation process. And we use double coupling dispersion and fine grinding to overcome the problems of slurry agglomeration and particle size distribution consistency. The performance of the slurry obtained in the ball milling process is more stable, which reduces the unit operating time of the ball milling equipment, improves product quality, and reduces production costs.
The company uses a unique new green release agent independently developed to prepare magnetic tiles. The new green release agent is an organic combination of microbial technology and surface release treatment technology, which can degrade oil molecules, reduce the oil content of the release agent, and restore the surface. active lipophilic factor. The product is combined with the surface release process, and the release effect of the magnetic tile is improved through a new release agent, and the surface finish of the blank is improved. The demoulding technology has the characteristics of simple preparation method and convenient application, and improves production efficiency.
By transforming the sintering preheating system equipment, the company reduces the water content of the sintered green body in the kiln, greatly reduces the waste rate caused by factors such as cracking and lack of oxygen during sintering, and improves the sintering density and mechanical strength of the product. Obtain good microstructure and magnet properties. The company has also realized the sintering base temperature that products with different performances can adapt to through formula adjustment. Products with different specifications, sizes and performances can be co-fired at the same temperature, which significantly improves the production efficiency of the sintering process. In addition, in terms of veneer loading and billet loading, the company has adopted a bulk stacking method that conforms to the company's product features of small shape and light weight after many tests, realizing heavy veneer loading, good sintering atmosphere, and high sintering yield. good effect.
By optimizing the parameters of grinding machines and other processing equipment and improving the process technology, the company has improved the consistency of product thickness to ≤0.02MM within L30MM and ≤0.04MM within L50MM, and has mastered the technology of three-phase motor magnets produced by grinding tooling. Breakthroughs have been made in technical difficulties in the industry, such as product precision and stable equipment performance, and certain innovations have been achieved in technology and equipment.
The company's magnetic tile products are developing in the direction of high efficiency, low consumables, and low energy consumption. For example, through atomic substitution and compound doping, the rare earth-free ZK-5B high-performance motor magnetic tile independently developed by the company reduces the coagulation of magnetic powder, improves the orientation effect, improves the material performance and reduces the production cost by using strong magnetic field to suppress and adding a double dispersant.
WeChat/Zalo/whatsApp: +86-15857968349(Jerry Ma)
Email: mahy@dymagnet.com
No. 28, Changsheng Road, Hengdian Town, Dongyang City, Jinhua City, Zhejiang, China.
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