Vol 23, No 3 (2021)

The article is dedicated to the memory of the outstanding Russian scientist-technologist , Honored Worker of Science and Technology of the RSFSR, Doctor of Technical Sciences, Professor Boris Kravchenko .

The article discusses the problems of introducing CAD systems integrated into complex automated production systems (PLM solutions). One of the reasons for the failures and low efficiency of projects for the implementation of complex automated systems is the lack of criteria for assessing their effectiveness, necessary for the organization of development management. A system of formalized indicators is proposed that allows for analysis and multicriteria optimization of the processes of creating integrated CAD systems. Four groups of indicators have been identified and defined: Functional indicators, presented in the form of tags, reflecting certain achievements in expanding the functionality of the system, increasing the completeness of system procedures, improving the quality of workflows and processed information; Financial and economic indicators, taking into account the customer’s requirements for the costs and timing of the project; Socio-economic criteria demonstrating improvements in the conditions for the activities of the personnel of the automated system; Indicators of the complexity of the solution associated with the level of automation of both design and production stages. The results of a study of projects of complex automation of the leading enterprises of the aircraft and automotive industry of the Samara region are presented. The introduction of a software and methodological complex made it possible to increase the level of automation of dispatching processes and operational planning of production, interconnected with the design and technological design. Due to this, the volume of work in progress has been significantly reduced and equipment changeovers have been minimized. In general, it can be stated that the introduction of a multi-criteria monitoring methodology at the design and production stages of the life cycle of mechanical engineering products can increase the efficiency of the development and implementation of complex automated systems.

The results of studies of surface quality parameters and accuracy of bearing rings after finishing abrasive machining of raceways (grinding and superfinishing) and after hydroblasting (HDB) hardening or microbead hardening with the use of cutting fluids are presented and refined.

This article discusses the design sequence of a special tool for processing shafts. An original design of the tool head is proposed, which allows simultaneous cutting, grooving, and chamfering of the shafts on both sides with axial feed with the possibility of adjustment to different diameters and depths. The calculations and operational tests of the tool head showed its functional suitability and reliability. The relatively low cost of manufacturing the tool, versatility, fast setup and changeover ensure high economic efficiency of processing.

The operating experience of metal-cutting machines made it possible to develop reasonable recommendations for the permissible limit values of temperature for the main subsystems of the machine, which determine the accuracy of processing. However, the decrease in the seriality of the manufactured metal-cutting equipment and the constant improvement of its designs require the development of models that are the basis of engineering techniques that allow at the design stage to predict the thermal picture of the main machine units that affect the processing accuracy. In connection with a significant number of factors influencing the formation of contact thermal resistance, and the difference in the weight of their action, it is proposed to use a pseudolayer (pseudo-medium), consisting of areas of actual contact and cavities filled with air or oil, for their comprehensive consideration in the thermal model of joining parts. To determine the significant factors that dominate the contact thermal resistance, a number of one-factor experiments were carried out. To develop a regression model of temperature change in the contact zone, a PFE of type 24 was performed. The results obtained were verified by the Cochran, Student and Fisher criteria.

O reduce the error in the appointment of the mode in the conditions of uncertainty of information for the first time developed mathematical models and algorithms that provide for the correction of the model parameters relating the input and output parameters of the process, according to the current information about the output parameters. Developed a plan of varying the controllable factors of the technological process, the methodology and the algorithm used to generate mathematical models of the machining process with time-varying parameters. Models take into account the mutual influence of the tool state parameters and the current processing parameters and their impact on the output parameters and allow you to calculate the output parameters of the process at different times. This makes it possible to create prerequisites for the purpose of machining mode with time-varying parameters in the conditions of uncertainty of technological information.

In the article, studies of the surface roughness during grinding with an abrasive tool made of SHS materials were carried out. Studies have shown that the surface roughness when grinding with SHS KR wheels increases in proportion to the increase in the radius of rounding of the grain top, plunge feed and inversely proportional to the speed of rotation of the wheel and workpiece, as well as the hardness of the material being processed.

The paper is devoted to the analysis of the known methodological support for quality assessment and control of communication services. The known approaches to quality assessment of communication services have mainly been developed in relation to the situation, characterized by the fact that each management system actually relied on its own, dedicated communication system. In this case, most of the results apply to analogue communication systems with predominantly assigned channels (paths) to certain information directions, which together reflect the structure of the control system. The synthesis of communication systems is based on the requirements of the respective control system. As a result of the analysis, the limitations of the known methodological support in the field of assessment and control of the communication services quality were revealed. In order to eliminate the identified limitations of the known methodological support in the field of assessment and control of the quality of communication services, the author has developed: analytical and simulation model of an information and telecommunication system with the required level of reliability of its elements; method for determining the parameters of the development directions of telecom operators’ networks; method for assessing the probabilistic-temporal indicators of the technical resource of the fragments of the information and telecommunication system, generating communication services of a certain type.