MULTIPLE-CRITERIA OPTIMIZATION OF OPERATIONAL MODES OF TECHNOLOGICAL PROCESSES

The issues that are rarely combined in one small study are viewed. First of all, this is a well-known problem of engineering support of a specified quality of hardened steels surface layer using a blade tool made of superhard materials and the state of microclimate of operating areas of metal-cutting machines. It had a shot at creating a mathematical model that combines these two objective functions. As a mathematical tool that allows optimizing the modes of finishing and fine turning, the linear- programming technique was applied, which visualises through its graphic image, a picture of the influence of the engineering constraints included in the model on the optimal values of the cutting speed and feed. On the basis of analytical studies, the dependences of the formation of hydrogen sulfide vapors in the operating areas of metal-cutting machines using sulfofresols of various brands as lubricating and cooling fluids were obtained. Theoretically, it has been established that the maximal influence on the intensity of hydrogen sulfide vapor formation is exerted by the temperature in the cutting zone, which is more effected by the lathe turning speed. The paper presents empirical dependencies ratios that allows finding an average temperature in the cutting zone in the process of various steels treatment, as well as high-strength alloys and non-ferrous alloys. The roughness and the degree of cold work coefficient were taken as parameters of the surface layer condition for cylindrical surfaces, which decisively determine the durability of the products under conditions of friction and cyclic loads. Testing of the obtained mathematical models made it possible to obtain optimal values of feed and cutting speed for finishing and fine turning of hardened steels 45 and 65G.