Deep processing technological process of sintered ndfeb magnet
You want to know about the deep processing of NdFeB strong magnets. Today it comes. This paper will introduce the deep processing process of sintered NdFeB magnets and details of each process.
Deep processing process of sintered NdFeB magnet:
Magnet blank - contour finishing - cutting - grinding - chamfering - electroplating - inspection, testing - finished products.
The outer contour finishing of magnet is usually finished by centerless grinding machine (cylindrical magnet) or plane grinding machine (square magnet), so that the rough magnet has regular outer contour and reaches the specified geometric dimension;
The cutting process is to use the diamond inner circle slicer or wire cutter to cut the finished magnet into the shape and size close to the finished product;
The fine grinding process is to process the size, shape and position tolerance of the cut magnet to the specified requirements of the finished product with a plane grinder, double-sided grinder or other grinder;
Chamfering is a pre-treatment process before electroplating, in order to reduce the uneven thickness of the coating caused by the relative concentration of current density on the edge of magnet during electroplating. Because of the small size and different shapes of the sintered NdFeB magnets, the free roll polishing process is the most suitable for the large-scale chamfering of the products. There are many methods of free roll finishing, such as vibration roll finishing, eddy current roll finishing, centrifugal roll finishing, spindle roll finishing and so on. Among them, the production efficiency of vibration roll polishing is high and the chamfering speed is fast, which has been widely used by the manufacturers of sintered Nd-Fe-B magnets;
The purpose of electroplating is to form a protective layer on the surface of magnet, which is usually realized by free roll plating process. For larger size magnet, hang plating process is used. The coating of sintered Nd-Fe-B magnet can be divided into Ni plating, Zn plating, phosphating, electrophoresis, alloy plating, composite plating, etc. according to the use environment and appearance requirements of the magnet.
In addition to electroplating, the surface protective layer of sintered NdFeB magnet also has physical vapor deposition (PVD) method. Physical vapor deposition can be divided into three categories: evaporation, sputtering and ion plating, which can form al, Zn, Cr coatings; chemical vapor deposition (CVD) can form Ti, Cr nitride, carbide coatings. In addition, the sintered NdFeB magnets can be treated by chemical passivation, electroless plating, hot dipping and thermal spraying.
The inspection and test process is to test the size, shape and position tolerance, appearance state, corrosion resistance of coating, magnetic properties and other specified indexes of finished magnet products.