The paper considers the use of simulation modeling in the reengineering of technological processes for repairing rolling stock units. The object of reengineering is the key sub-processes repair of units and parts a bogie model 18-578 of a gondola car. The purpose of the reengineering of the considered technological process is to increase its throughput. When choosing a reengineering option, the indicators of work in progress and the degree of utilization of resources used for repairs were taken into account. The assessment of these indicators was carried out on the basis of modeling in ARENA functioning of the formed variants of the technological process reengineering. The model of the current variant of the technological process of repair is a model of the «AS IS» type, and the models of the process reengineering variants act as the «AS TO BE» models. When simulating, the technological time of repair operations was taken equal to the standard values specified in the technical documentation for the organization and support of the repair technological process under consideration. The schedule and organization of the repair shift were also taken into account. The simulation results made it possible to formulate recommendations for choosing a reengineering option for the technological process under consideration.

The article discusses the use of a number of indicators of the reliability of the functioning of the hot forming process to substantiate the choice of the number of die inserts (die streams) and selection of grades of tool steels for their manufacture. There are such used reliability indicators as the probability of the absence of typical defects in the shape of the stamped forgings, the probability of predominant types of exploitative refusals of the stamp, and the absence of failures in the implementation of the technological process as a whole. The rationale for the expediency of choosing a pre-stream of the die for stamping an axisymmetric forging with a high degree of complexity taking into account the possibility of occurrence of such shape defects as clamping, shooting, and incomplete forging radii during stamping, is considered. When the choice of the grade of tool steel for die inserts was taken into account, there was the occurrence of such typical types of their exploitative refusals as adhesion wear of die streams, the formation of hot cracks and plastic crushing of the forming elements of the stamp streams. The appropriate organizational and technical decisions are adopted on the basis of a comparison of cost indicators characterizing the production costs due to scrap forgings. They are caused by the formation of shape defects during stamping and the occurrence of exploitative refusals of dies. In addition, there are the costs for the manufacture of more complex die tooling and its exploitation, i.e. production quality costs.

The paper considers the possibility of using fuzzy logic algorithms in the development of automatic control systems for precision machining of cylindrical surfaces. For the theoretical justification of the use of these algorithms, a mathematical model of the turning process and a mathematical model of the fuzzy-controller were developed. When developing the fuzzy-controller mathematical model, its input and output linguistic variables were determined, their fuzzification was carried out. The base of fuzzy linguistic rules that formed the algorithm for controlling the processing accuracy was developed. The defuzzification method was chosen, which allows determining the value of the control value depending on the value of the mismatch of the controlled value. The value of the error of the dynamic adjustment of the processing process was considered as an input linguistic variable fuzzy-regulator was considered, and the value of the correction made to the value of the longitudinal feed - as its output linguistic variable. The results of the comparative theoretical analysis of the processing accuracy in the process system without control were studied along with the control of the classic proportional regulator and proportional fuzzy-controller using the fuzzy inference algorithm Mamdani. Based on the results of the comparative analysis, it is concluded that the use of fuzzy logic algorithms is promising in the development of automatic control systems for precision turning of machine parts.

The paper discusses a number of issues related to the use of simulation modeling of technological processes of repair units of the rolling stock. A simulation model for modeling the technological process of repairing a critical rolling stock node in the ARENA environment is presented and described. The analysis of the simulation results in the context of setting and solving the main tasks of the organization and production management is carried out.

Physical-probabilistic models of formation and breaking of adhesive bonds between the metal blade cutting tool and workpiece material are offered. Use of these models for an estimation of dynamics of major flank wear surface of the cutting tool is considered. Results of calculation of wear of the cutting tools in comparison with the results of experimental studies published in the open press are presented.

The article deals with valuation of reliability requirements of productions operations in designing processes of workparts machining with regard to the quality of machined parts. The valuation procedure is based on simulation of a process of an open multi-phase of mass servicing of machined workparts and also simulation of an isolated production operation of a single-channel mass servicing system with failures.The authors offer two ways for determining reliability requirements for production operations: the method of even distribution in reliability requirements and the method of distribution in reliability requirements with use weigh factors. Designed formulas have been obtained and valuations examples are given for both methods.