抄録
In recent years, many machinable ceramics are used in precision instruments and electronic components. The ceramics with higher machinability and processibility are desired for the miniaturization and lightening of the product. The Si3N4/BN ceramics was developed for the purpose of this improvement. The purpose of this study is to clarify the mechanism for the machinability of known machinable ceramics and newly developed Si3N4/BN ceramics by the orthogonal cutting test and micro-fracture test. The cutting mechanism of both ceramics is discussed from viewpoint of the relation between cutting forces, waveform of the AE signal and SEM image of the cutting surface. In the cutting test by a new type of testing machine, the cutting speed was 0.17 m/s and the depth of cut was 0.2 mm. The main results obtained were follows: (1) The generation interval of the undulate acoustic wave of the AE signal for the Si3N4/BN ceramics is shorter than that for the machinable ceramic. In fact, the developed cracks length was smaller in Si3N4/BN ceramics that has the high machinability. (2) Cutting force and fracture energy for the Si3N4/BN ceramics was both lower than that of the machinable ceramics. In fact, the processing was possible by the small force.
