Vadym Stupnytskyy

Bio: Vadym Stupnytskyy is an academic researcher from Lviv Polytechnic. The author has contributed to research in topics: Machining & Hobbing. The author has an hindex of 3, co-authored 11 publications receiving 24 citations.

Optimization of the Technological Process Based on Analysis of Technological Damageability of Castings

Abstract: Reasons for machine failures are analyzed in the article. The primary role of the machining and assembly process structure for the formation of the product’s damages is noted. Improvement of the operating properties and reliability indicators are considered as a result of the pre-production technological system optimization as a part of the product’s Life Cycle Support. The relationship between the technological damageability and the workpiece’s material structure is presented in a formalized form. Methods for assessing the degree of the material’s damage based on the results of direct and indirect measurements of the material’s mechanical properties without destroying are analyzed. The method of experimental studies is described. The advantages of the method of LM-hardness analysis and evaluation of the heterogeneity of the workpiece’s physical structure are submitted. The impact of the technological route structure on forming the process of product damage was studied based on experimental researches. Technological damageability is proposed to be used as a criterion for the analysis of the technological process of workpiece machining. This method is an energy approach to the research of the product’s damage accumulation.

Computer-Aided Conception for Planning and Researching of the Functional-Oriented Manufacturing Process

Abstract: The methodological principles for the functional-oriented technological process planning are presented in the article. The introduction of a comprehensive system for ensuring the engineering product’s life cycle requires taking into consideration the operating conditions of the most loaded parts in the product not only at the design engineering stage, but also at the stage of the technology planning. Computer Aided Forming (CAF) system that implements the relationship between the technology of forming products with the conditions of their potential exploitation should be added to the integrated CAD/CAE/CAPP/CAM system. The results of simulation of power, temperature and stress-strain parameters are the basis for developing predictive models of influence of the structure and parameters of the functional-oriented technological process on the formation of the wear parameters and corrosion resistance of the machined product. It is proved that the residual stresses reflect the interference pattern of the fluctuation tensile (frictional and thermal) and compressive (force) loads, the dynamic picture of the deep thermal effects of the formation process and the peculiarities of the structural-phase transformations. It is shown, that the specific value of the strain component of roughness increases as a result of increased cutting speed and reduction of feed, which contributes to the formation of the surface microrelief with significant values of the reduced valley depth. This reduces the concentration of oxide products on the functional surface, resulting in increased product’s corrosion resistance.

Simulation Study of Cutting-Induced Residual Stress

Abstract: The use of the finite element analysis (FEA) is an effective method for studying the surface layer deformation appeared from inherited residual stresses. This paper is devoted to the analysis of the effect of residual stresses to the service properties of parts and the development of a cutting-induced residual stresses simulation using the DEFORM software. The influence of residual stresses on the operational properties of machined parts is investigated. The fatigue strength of the product, which is provided as the result of forming in the cutting process of the surface layer structure, residual stresses and deformations, is used as a criterion for the decision-making about optimal structure and parameters of the functionally-oriented technological process. The causes of the occurrence of machine-induced residual stresses for different workpiece materials have been analyzed. The simulation model of residual machining-induced stresses is described. The functional dependence of the stress-strain state reflects the interference pattern of the frictional, force loads and the variable process of the deep thermal effects. It is proved, that the compression part of this cycle is determined by external load, and tensile—by residual stresses.

Improved method of gear hobbing computer aided simulation

Abstract: Simulation studies of the hobbing process kinematics can effectively improve the accuracy of themachined gears. The parameters of the cut-off layers constitute the basis for predicting the cutting forces and the workpiece stress-strain state. Usually applied methods for simulation of the hobbing process are based on simplified cutting schemes. Therefore, there are significant differences between the simulated parameters and the real ones. A new method of hobbing process modeling is described in the article. The proposedmethod ismore appropriate, since the algorithm for themomentary transition surfaces formation and computer simulation of the 3D chip cutting sections are based on the results of hobbing cutting processes kinematics and on rheological analysis of the hob cutting process formation. The hobbing process is nonstationary due to the changes in the intensity of plastic strain of the material. The total cutting force is represented as a function of two time-variable parameters, such as the chip’s 3D parameters and the chip thickness ratio depending on the parameters of the machined layer.

Finite Element Analysis of Thermal State and Deflected Mode During Titanium Alloys Machining

Abstract: Titanium alloys are difficult to machining due to their physical and mechanical properties. An effective method of research the cutting process is to study using simulation models. The article describes the results of rheological simulation of titanium alloys cutting processes using the DEFORM software. The results of the stress-strain and thermodynamic state of the workpiece and tool, cutting force studies in the chip formation zone depend on the machining parameters are given. It has been proven that the process of chip formation in the machining of titanium and nickel alloys takes place under conditions of unstable cutting, which contributes to the generation of residual stresses, which arise synchronously with the increase of radial cutting force. The result of this process is an intense tool wear and dynamic instability in the cutting zone. The machinability of the titanium alloys essentially depends on the cutting parameters. The main causes of low workability are high cutting temperature, saw-tooth type of chip (as a result of an asynchronous change in longitudinal and transverse cutting forces), the adiabatic process of the chip formation, tool vibration and intense tool wear.

Computer-Aided Conception for Planning and Researching of the Functional-Oriented Manufacturing Process

Abstract: The methodological principles for the functional-oriented technological process planning are presented in the article. The introduction of a comprehensive system for ensuring the engineering product’s life cycle requires taking into consideration the operating conditions of the most loaded parts in the product not only at the design engineering stage, but also at the stage of the technology planning. Computer Aided Forming (CAF) system that implements the relationship between the technology of forming products with the conditions of their potential exploitation should be added to the integrated CAD/CAE/CAPP/CAM system. The results of simulation of power, temperature and stress-strain parameters are the basis for developing predictive models of influence of the structure and parameters of the functional-oriented technological process on the formation of the wear parameters and corrosion resistance of the machined product. It is proved that the residual stresses reflect the interference pattern of the fluctuation tensile (frictional and thermal) and compressive (force) loads, the dynamic picture of the deep thermal effects of the formation process and the peculiarities of the structural-phase transformations. It is shown, that the specific value of the strain component of roughness increases as a result of increased cutting speed and reduction of feed, which contributes to the formation of the surface microrelief with significant values of the reduced valley depth. This reduces the concentration of oxide products on the functional surface, resulting in increased product’s corrosion resistance.

Optical and Mechanical Properties of Layered Infrared Interference Filters

Abstract: The design and manufacturing technology of interference-absorbing short-wave filters based on a layered composition of Si–SiO on a sapphire substrate of various shapes was developed. A transition layer of SiO was applied to the surface of the substrate, alternating with layers of Si–SiO with an odd number of quarter-wave layers of materials with high (Si) and low refractive indices (SiO), and the application of an outer layer of SiO as an appropriate control of the materials’ thickness. The optical properties of the infrared light filter were studied. It was established that the created design of the light filter provides the minimum light transmission in the visible region of the spectrum from 0.38 to 0.78 µm and the maximum in the near infrared region from 1.25 to 5 µm and has stable optical indicators. A method for studying the stress–strain state and strength of a multilayer coating of a light filter under the action of a local arbitrarily oriented load was developed. For simplicity in the analysis and for obtaining results in the analytical form, the one-dimensional model of the configuration “multilayer covering—firm substrate” constructed earlier by authors was used. From a mechanical point of view, the upper protective layer of the multilayer coating was modeled by a flexible plate, and the inner operational composite N-layer was subjected to Winkler’s hypothesis about the proportionality of stresses and elastic displacements.

Development of the fundamental diagram of the formation and transformation of the products properties during their manufacturing

Abstract: In object-oriented technologies of mechanical engineering production the step-by-step execution of interconnected design stages of technological process of product manufacture is used. A systematic approach to research and qualitative modelling of real physical processes, taking into account the operational characteristics of products and machines at all levels of research is ignored. As a rule, the object-oriented technological processes do not track the change of the products properties during their manufacture from the position of technological inheritability for all stages and substages of the Life Cycle Support of Product. Therefore, the development of scientific and applied principles of technological inheritability of quality parameters to provide the operational characteristics of products in the design of function-oriented technologies is a priority item of modern mechanical engineering. The structure of functional-oriented technology is closely related to the stages and substages of Life Cycle Support of Product. From the standpoint of continuous damage mechanics, Life Cycle Support of Product is considered to be a single process of exhaustion of the material plasticity margin under the influence of certain load modes in accordance with the technological inheritance of the product properties. The basic chart of the formation and transformation of the products properties from the point of view of mechanics of technological inheritability is developed. This chart, in contrast to previous research in this area, takes into account the significant impact of the stage of blanks manufacture in the technological process structure on the formation of technological parameters and operational characteristics of products.

Development of the Technique for Designing Rational Routes of the Functional Surfaces Processing of Products

Abstract: The quality of the products is a wide concept, which is closely related with the development and design of the stage parts and stages of the Product Life Cycle. Therefore rational technological processes of products machining provide regulated machining accuracy, quality of surface layers of the products, their operational characteristics and reliability indicators. Traditional techniques for planning a rational route of treatment of product surfaces only ensured to form restricted number of quality parameters of products. Developed technique of planning a rational route of treatment of products provides relationships between material homogeneity of product and technological methods of surfaces treatments using the LM-hardness method. This technique is realized for steel products including for shaft 6E4-2717.00.00.01. The values of the Weibull homogeneity coefficients (m) during machining of shaft 6E4-2717.00.00.01 increasefrom 6.12–11.46 to 198.23–344.59. At that the material constants Am in the technological chain “input blank – output product” change from 0.814 to 0.966 during machining of shafts 6E4-2717.00.00.01 by cutting and abrasive methods of processing.