ДОСЛІДЖЕННЯ ШОРСТКОСТІ ПОВЕРХНІ ПРИ ОБТОЧУВАННІ ХРОМОМОЛІБДЕНОВОЇ СТАЛІ

Abstract

Surface roughness is one of the parameters of product quality, that’s why the research of cutting mode impact on surface roughness is a current topic. The diversity of cutting tools and materials to be worked leads to the need for more detailed study of the impact of cutting modes on surface roughness.Previous researches have established that the radius of curvatureof cutting tool and the cutter feed have an impact on surface roughness. There are also studies for assessing cutting speed and cutting depth effects on surface roughness. But these studies are not complete and exhaustive, because they have been done for selected materials, cutting tools and cutting modes.The aim of the research described in the article is a scientific inquiry of cutting mode impact on surface roughness in turning of chromium-molybdenum steel 38ХМand the search for optimal cutting modes for this steel.The mathematical relationship between surface roughness and cutter feed, cutting depth, cutting speed was written in the form of power function. The range of variation was chosen. Regression coefficients were defined on the methodology of full factor experiment of type 23. The constructed mathematical model has been checked for adequacy. The equation of surface roughness dependence on cutting mode in turning of 38ХМsteel was obtained.Finding the best possible combinations of cutter feed, cutting depth, cutting speed values for turning of 38ХМsteel was undertaken using the Taguchi method. It was based on the search for technological modes in which the evaluated quality parameter is least affected by uncontrolled factors.As a result of the research it is established that cutting speed and cutting feed have the greatest impact on surface rough-ness. It is also shown that cutting depth has a negligible impact on surface roughness. It is proved that the machining processed at small cutting depthand small feed and large cutting speed is most appropriate. The optimal cutting modes for turning, providing minimal surface roughness are determined.Thus, the complex use of full factor experiment method and the Taguchi method made it possible not only to obtain the equation for the dependence, but also to determine optimal cutting modes.