Manufacturing process of bonded NdFeB magnet:

1. Extrusion molding: It is basically the same as the injection molding method, the only difference is that the pellets are extruded into the mold through a cavity after heating for continuous molding. Similarly, nylon 6, polyamide, polyester, and polyethylene are used to produce thin-walled, thin-walled cylindrical or long ring magnets that are difficult to achieve in other processes, such as ferrite, samarium cobalt magnets and neodymium iron boron magnets.

2. Compression molding: mix the magnetic powder and the adhesive according to the proportion, granulate and add a certain amount of coupling agent, press and shape in the mold, and solidify at 120°~150° to finally obtain the finished product. Use solid epoxy resin or phenolic resin, add 1%~5%, can be bonded according to the larger size and simple shape of permanent magnet, generally adopt cathodic electrophoresis, spraying, evaporation and other methods for coating protection

3. Calendering: The magnetic powder and the adhesive are uniformly mixed in a volume ratio of about 7:3, rolled to the required thickness and then processed into a finished product. Generally, ethylene and nitrile rubber are used as the adhesive Adhesive, to bond with ferrite or part and a small amount of NdFeB. Generally, surface treatment is not required, and it is protected or decorated with a film. NdFeB requires nickel plating.

4. Injection molding: mix the magnetic powder with the adhesive, heat and mix, granulate, dry, then send the spiral guide rod to the heating chamber for heating, inject into the mold cavity for molding, and cool down to get the finished product. Generally, nylon 6, polyamide, polyester and pvc are used in an amount of 20% to 30% (volume fraction), together with a rigid bonded permanent magnet with a complex shape. After ferrite, samarium cobalt magnet and neodymium iron boron magnet, surface treatment is not required.