A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

The second stochastic longevity model

The article is devoted to the issues of the second stochastic model of longevity. This is a model that takes into account the probabilistic nature of the durability process, taking into account the stochastic characteristics of the object's parameters and loads. This approach makes it possible to describe the resource of the elements of mechanical systems as a random variable, taking into account the random nature of the development of degradation processes, as well as to take into account the variety of factors affecting durability. The obtained model makes it possible to determine from the experiment on long-term durability a specific type of stochastic kinetic differential equation of durability.
Keywords: durability; the second stochastic model of durability; statistical series; the law of durability distribution.

A. I. Kanareykin (Russian State University for Geological Prospecting (MGRI), Moscow)

Heating of the end rod by an instantaneous point heat source

The article is devoted to the theoretical issues of heat transfer through a rod. The paper considers the process of heating the end rod by a point source. Therefore, the process under consideration is non-stationary. The solution to the problem is given using Green's functions and is presented as a series. The obtained result can be applied when calculating the heat transfer of cylindrical parts.
Keywords: core; heating; thermal conductivity; nonstationary; Green's function.

V. A. Grechishnikov, A. V. Petrov (MSUT «STANKIN», Moscow)

Investigation of the effect of geothermal parameters of the cutting element of a prefabricated step drill on the stress-strain state of the tool

This article presents the results of a study of the influence of geometric parameters on the stress-strain state of the cutting element of a prefabricated step drill during the processing of step holes. The relevance of the work lies in the need to optimize the design of the tool to increase the efficiency of processing step holes in the conditions of serial, large-scale and mass production. The purpose of this study is to get ahead of how geometric parameters affect the stress-strain state of the cutting element of a prefabricated step drill. The study is conducted using the finite element method in the SolidWorks Simulation software package. The front angle, the radius of rounding, and the angle of inclination of the main cutting edge are considered as the studied parameters. In the course of the work, mathematical models of the dependence of the stress-strain state of the cutting element on geometric parameters were obtained, and it is also found that the angle of inclination of the main cutting edge has the greatest effect on the stress-strain state. A regression equation is obtained in the course of the study, which can be used in the design of the instrument. The practical significance of the work lies in the possibility of using the results to optimize the geometry of the tool at the design stage. 
Keywords: prefabricated step drill; stress-strain state; geometric parameters; finite element method; computer modeling.

V. I. Erofeev, A. I. Ermolaev, S. N. Okhulkov (Mechanical Engineering Research Institute of RAS, Nizhny Novgorod); A. S. Plekhov (Lobachevsky University, Nizhny Novgorod)

Hydraulic loader for hot crank stamping press equipped with magnetorheological mount (part 2)

The paper proposes a solution to the urgent problem of checking hot crank stamping presses (HCSP) when loading the ram with a specified force. Currently, in HCSP, the control and calibration of the press force is carried out by strain gauge sensors (strain gauges). For this purpose, strain gauges are glued to the press parts subject to the greatest deformation (ram, tie rods, frame, etc.). Also, in the practice of operating HCSP, the verification of the press loading is carried out using strain gauges calibrated by a hydraulic loader. The hydraulic press loader is designed to verify the presses when loading the ram with a specified force at a small stroke of the ram, at the last stage of pressing during stamping. Strain gauges are glued to the spacers of the hydraulic loader. The paper presents studies on upgrading the HCSP hydraulic loader with a spacer made on the basis of a self-healing fuse with an elastic force converter and a magnetorheological hydraulic mount. A method and means are proposed for upgrading the HCSP hydraulic loader on the basis of magnetorheological hydraulic mounts instead of strain gauges, allowing for real-time verification of the loading process in the press.
Keywords: crank hot stamping press; strain gauge sensors; hydraulic loader equipped with spacers; self-restoring fuse with elastic force converter; magnetorheological hydraulic mount.

I. G. Chepovskiy (Vintech LLC, Chelyabinsk)

A technique for optimizing the parameters of a hinged belt conveyor for chip removal for metalworking machines

The relevance of the issue under consideration is related to the need to increase the reliability and technological reliability of chip removal processes in the process of metalworking in conditions of increasing automation and complexity of the layout of metalworking equipment, which is accompanied by an increase in chip volumes, increased use of coolant and increased requirements for the continuity of machine tools. Engineering limitations associated with the variability of the shape and condition of the chips, spatial limitations of the machine space, increased loads on conveyor assemblies and the risk of unscheduled equipment shutdowns are becoming essential, which necessitates a systematic approach to choosing the parameters of chip removal conveyors. The purpose of the work is to develop and substantiate a methodology for optimizing the parameters of a hinged belt conveyor for chip removal for metalworking machines, taking into account the operating conditions and equipment layout. The main results of the scientific research: a method for selecting conveyor parameters based on the chip profile, operating conditions and machine layout is proposed; a generalization of design solutions for increasing the service life and preventing failures is performed; a model of the relationship between conveyor parameters, operational risks and the resource of nodes, tested in production conditions, is presented. The practical significance of the research lies in the possibility of applying the developed methodology in the design and modernization of chip removal systems at metalworking enterprises, as well as in the selection and adaptation of chip removal conveyors to specific operating conditions in order to increase reliability, reduce wear and ensure continuity of the production process.
Keywords: conveyor for chip removal; metalworking machines; articulated belt conveyor; chip removal; operating conditions; design parameters; reliability of equipment; resource of components; production systems; engineering methodology.

D. P. Gasyuk, V. V. Gusev (Peter the Great St. Petersburg Polytechnic University, St. Petersburg)

Analyzing the influence significance of second-order causes on product quality factors of machine-building enterprises considering their weight indicators

This article analyzes the influence of second-order causes on the product quality factors of machine-building enterprises. The primary objective of the study is to identify the most significant secondary causes, provide an expert assessment of their weight indicators, and perform a mathematical calculation of the probabilities of their non-influence on key aspects of the production process. The relevance of the research stems from the necessity of a profound understanding of the dependencies between second-order factors and the quality of finished products, which enables the optimization of management efforts and the enhancement of control efficiency. The methodological framework of the study is based on the application of the Ishikawa diagram for the initial systematization of factors. To obtain empirical data, an expert survey was conducted involving 80 employees of the machine-building enterprise CJSC «Krasny Oktyabr – Neva» divided into eight working groups. The study yields quantitative assessments of the significance of various factors. It was established that for the «technological process», the most critical causes are risks (0,26) and the human factor (0,22). In the category of equipment setup, regular maintenance holds key importance (0,34), while work experience is paramount for employee competencies (0,28). Calculations of the probabilities of non-influence showed that for the risk factor, this value is 0,4339, confirming a moderate positive correlation. It is concluded that the technological process remains the most complex element to control.
Keywords: engineering technology; process quality; causes, weight indicators; probability of influence.

D. P. Gasyuk, V. V. Gusev (Peter the Great St. Petersburg Polytechnic University, St. Petersburg)

Determination of the factors' influence degree on the properties of technological process in machine-building production

This article examines current issues of ensuring and improving the quality of technological processes in modern mechanical engineering. The purpose of the study is a comprehensive determination of internal and external conditions, as well as factors affecting the parameters of the technological process, followed by a quantitative analysis of their impact on its key properties. The research methodology is based on an expert survey involving 80 specialists from the «Krasny Oktyabr – Neva» enterprise, divided into equal target groups, as well as representatives from 48 various machine-building companies. The study utilized visualization methods in the form of mind maps to classify environmental conditions and statistical analysis using Pareto charts to prioritize influence factors. During the research, properties such as accuracy, stability, productivity, and reliability were analyzed in detail. The analysis results showed that «Risks» are the most significant and difficult-to-control factor, exerting a dominant influence on the accuracy (33 %), stability (39 %), and reliability (31 %) of the processes. Simultaneously, it was revealed that «Technical Equipment» has the most significant impact on productivity (33 %). It is concluded that the integration of risk management systems into production practice is necessary to achieve specified product quality standards.
Keywords: mechanical engineering technology; process quality; conditions; factors; risks.