Вплив абразивного інструменту та режимів шліфування на рівень контактних температур композиційних самозмащувальних деталей вузлів поліграфічних машин

The article presents the experimental research results of specific features of the instantaneous contact temperatures formation at the working surfaces during grinding process of composite self-lubricating parts based on industrial grinding waste of tool steels 7KhG2VМF, R7М2F6, 05Kh12N6D2МFSGТ, intended for equipping of heavy-duty friction units in printing machines. Such antifriction parts operate under aggressive environmental conditions, namely, air oxygen, temperature loads during operation up to 450° C, specific loads up to 7 MPa, rotation speeds up to 10,000 rpm/min, and they were recommended for industrial use. It has been shown that during process of grinding composites the material of abrasive grain, the grain size of the tool and the grinding wheel’s bonding material significantly affect the magnitude of the temperature field (instant contact temperatures in the finishing area) on the processing zone. It was recommended to use grinding wheels based on green silicon carbide (63C) on a glyphtale bond with a grain size of 14−20 μm to form working surface’s high quality parameters of the composite antifriction parts based on new materials. This allows avoiding an increase in temperature at the processing zone, which results to the significant phase-structural changes, plastic deformations and a decrease of the surface layer properties. Taking into account the temperature field that occurs in the finishing zone, high quality parameters of the parts working surfaces manufactured from new composites based on tool steels grinding waste can be obtained in compliance with the following recommended cutting conditions: perform fine abrasive grinding at a wheel speed Vw — 22 m/s, product speed Vp — 2 m/min, cutting depth t = 2−5 μm, cooling — 3 % solution of soda emulsion. The use of such technological modes for fine grinding of new composite self-lubricating parts will allow ensuring the working surface’s stable high quality parameters of antifriction parts for high-loaded printing machines units.