FINISHING TECHNOLOGY OF BED OF METAL-CUTTING MACHINES

Abstract

Processing large-sized parts is very time consuming, associated with a lot of time. Therefore, one of the main issues that have to be addressed in heavy engineering is to increase the processing productivity as a result of the use of advanced technological solutions, a further increase in production equipment, its specialization, mechanization and partial automation. Modern machine tools are characterized by a significant proportion of small-scale and single forms of production. Metalcutting machines produced for machining parts are characterized by high metal consumption and high labor intensity of their manufacture. For processing the bed of machines, universal equipment is used, including those with numerical program control (CNC), or technological complexes are created based on the use of unique equipment, basing devices, as well as original tools. Due to the specific features of the processing of heavy and large-sized beds of metal-cutting machines and the low seriality of their production, in the development of technology it is impossible to mechanically introduce progressive methods and methods of processing, as well as work organization that are widely used in large-scale and mass production of industries not related to heavy engineering. When cutting the bed, there is often a need for original technical solutions. The quality of finishing of the surfaces of the guides of the beds of metal-cutting machines significantly affects their wear resistance, and, consequently, the duration of preservation of accuracy during operation by the machine (Antonenko Y.S. (2019); Gagarin V.O. (2016)). In the process of finishing the guides, their specified flatness, straightness, accuracy of the relative position of the guides and the relative position of the surfaces forming the guides are achieved, the specified parameters of surface roughness and physical and mechanical properties of the surface and surface layers of the metal of the guides are achieved (Pukhovskiy E.S.,( 2021); Tekhnologia verstatnikh robit (2015)). Therefore, extremely relevant in the domestic machine tools, which should be revived, is the problem of finishing the surfaces of the bed. Of all the parts of the machine, the bed performs one of the most important functions both in the process of its assembly and during operation. It is the basic part by which it is connected and consistent with the accuracy necessary for the operation of the machine, most of the components and a significant number of its parts (Design and analysis of machine tool bed.,( 2018)). The criterion for determining the quality of the bed is its initial accuracy and roughness of rubbing surfaces, as well as the ability to maintain these indicators during operation. Therefore, it is especially important when assigning processing processes, especially in final operations, to analyze the influence of accepted methods and methods of processing on the performance characteristics of parts, to choose from them those that carry good technological heredity ( Design and analysis of machine tool bed.,( 2018) ; Veselovskaia N.P. (2015); Application of mineral casting for machine tools beds.(2013)). Thus, the study of methods for finishing the surface of the bed is an urgent problem. At the same time, it is necessary to solve the issue of not only the sequence of operations in order to obtain quality indicators – accuracy, straightness, surface roughness, but also to achieve quality indicators of the surface layer, which ensure the durability and accuracy of the machines. A significant reserve for increasing labor productivity in heavy engineering is the rational organization of the production of large-sized parts, based on the use of group technological processes, typification of processes, normalization of equipment and tools, centralization of technological preparation of production, introduction of scientific and technological achievements. The issues of improving technological processes in serial and mass production of mechanical engineering branches not related to heavy engineering are widely covered in the technical literature ( Modelling and analysis of CNC milling machine, (2018); Study of application of a granite composite material in five-axis CNC-VMC machine tool, (2022)). There are no works in which the main issues of production technology for large-sized heavy engineering are systematized, they are partially covered only in disparate publications (Design and analysis of machine tool bed.,( 2018) ; Veselovskaia N.P. (2015); Application of mineral casting for machine tools beds.(2013)). The main tasks in the processing of bed machines are: achieving the required geometry of accuracy, surface roughness and physical and mechanical properties of the surface layer (( Pukhovskiy E.S., (2021); Antonenko Y.S. (2019)).). Finishing operations, during which the physical and mechanical properties of the surface layer of massive parts are formed, and therefore their operational qualities, are based on cutting materials and other progressive material processing processes (( Pukhovskiy E.S., (2021); Application of mineral casting for machine tools beds.(2013)). In the process of cutting, the surface layers have a slight hardening, and sometimes even strengthen. In the case of this method of processing, it is impossible to adjust the roughness of the surface, especially the shape of micro-irregularities, as well as the physical and mechanical properties of the surface layer using the cutting machine tools. Recently, there has been a revival of work on the use of materials unusual for the manufacture of beds, such as granite, polymeric materials, etc. (Application of mineral casting for machine tools beds., (2013); Modelling and analysis of CNC milling machine, (2018); Study of application of a granite composite material in five-axis CNC-VMC machine tool, (2022)). However, the greatest attention is focused on the improvement and development of traditional technological operations for this industry, such as grinding, lapping, rolling, rolling by rollers, pneumovibrodynamic processing and so on (Application of mineral casting for machine tools beds., (2013); Modelling and analysis of CNC milling machine, (2018); Study of application of a granite composite material in five-axis CNC-VMC machine tool, (2022)). These technological processes provide high operational properties of mashine-tool beds, including modern CNC machining centers that operate in an automatic cycle in flexible production systems (Tekhnologia verstatnikh robit (2015); Gagarin V.O. (2016); Veselovskaia N.P. (2015)). The purpose of the work. Analysis and development of progressive technological processes of finishing large-sized beds of metal-cutting equipment to ensure the accuracy and productive operation of individual machines and complexes of heavy engineering.