The ceramic material used in the aluminum nitride ceramic heating plate is usually formed by hot pressing and sintering. Since sintering often brings deformation and shrinkage, it is generally necessary to further use CNC machining tools for finishing to ensure the dimensional accuracy and shape accuracy of the parts. However, the aluminum nitride heating plate material generally has a large elastic modulus, high hardness, high brittleness, and strong crack sensitivity. Therefore, its machining difficulty is mainly manifested in machining hardness and machining brittleness.
The processing difficulty of the aluminum nitride heating plate is relatively high. At present, the common alumina processing equipment includes: ceramic CNC machining tools, internal grinding, external grinding, punching machines and so on. These devices are usually used together to achieve the best results. The requirements for the technical level of processing machines and operators are also relatively high. It usually takes a master with several years of experience to complete the processing of this difficult aluminum nitride heating plate product.
Processing brittleness of aluminum nitride heating plate: Usually, the microstructure of aluminum nitride heating plate is equiaxed grain, which is a polycrystalline structure composed of ionic bonds or covalent bonds, so the fracture toughness is low, and the external Under the action of the load, the stress will cause fine cracks on the surface of the ceramics, and the cracks will rapidly expand and cause brittle fractures. Cracked small gap. The reason for the collapse phenomenon is:
(1) The final separation of the cut part of the material and the machined surface is caused by tensile failure, which is not the result of normal cutting.
(2) Cracks caused by chipping and cutting deformation generally crack down along the surface of the workpiece. At this time, due to the cutting tensile stress, the cutting and the bonded workpiece substrate are peeled off together to form a chipping phenomenon. It should be noted that the greater the tensile stress, the more serious the chipping phenomenon, which may lead to the waste of the entire workpiece
It is an unavoidable phenomenon that the aluminum nitride heating plate will collapse during the processing. In order to minimize the occurrence of the collapse, a special machine tool for ceramics – ceramic engraving and milling machine has been developed for this material. , The emergence of ceramic engraving and milling machines has made up for the poor protection performance of ordinary engraving and milling machines, poor machine tool rigidity, low speed, and unreasonable structural design.
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