Wyniki wyszukiwania - BazTech

1

Hob wear prediction based on simulation of friction, heat fluxes, and cutting temperature

Hrytsay Ihor, Stupnytskyy Vadym

Archive of Mechanical Engineering

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2023

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LXX, nr 2

271--286

EN

Based on comprehensive interrelated mathematical and graphical-analytical models, including 3D cut layers and simulation of contact, strain, force, and thermal processes during gear hobbing friction forces, heat fluxes, and temperature on the teeth of the hob surface are investigated. Various physical phenomena are responsible for their wear: friction on contact surfaces and thermal flow. These factors act independently of each other; therefore, the worn areas are localized in different active parts of the hob. Friction causes abrasive wear and heat fluxes result in heat softening of the tool. Intense heat fluxes due to significant friction, acting on areas of limited area, lead to temperatures exceeding the critical temperature on certain edges of the high-speed cutter. Simulation results enable identification of high-temperature areas on the working surface of cutting edges, where wear is caused by various reasons, and make it possible to select different methods of hardening these surfaces. To create protective coatings with maximum heat resistance, it is advisable to use laser technologies, electro spark alloying, or plasma spraying, and for coatings that provide reduction of friction on the surfaces – formation of diamond-containing layers with minimum adhesion properties and low friction coefficient on the corresponding surfaces.

2

Simulation of loading and wear rate distribution on cutting edges during gears hobbing

Hrytsay Ihor, Stupnytskyy Vadym, Topchii Vladyslav

Archive of Mechanical Engineering

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2021

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LXVIII, nr 1

51--76

EN

Results of complex mathematical and computer simulation of gear hobbing are given. A systematic approach to research allowed for the development of simulation models and sequencing of all aspects of this complex process. Based on the modeling of non-deformable chips, a new analytical method for analyzing hobbing has been proposed. The shear, friction and cutting forces at the level of certain teeth and edges in the active space of the cutter are analyzed depending on the cut thickness, cross-sectional area, intensity of plastic deformation and length of contact with the workpiece has been developed. The results of computer simulations made it possible to evaluate the load distribution along the cutting edge and to predict the wear resistance and durability of the hob cutter, as well as to develop measures and recommendations for both the tool design and the technology of hobbing in general. Changing the shape of cutting surface, or the design of the tooth, can facilitate separation of the cutting process between the head and leading and trailing edges. In this way, more efficient hobbing conditions can be achieved and the life of the hob can be extended.

3

Comprehensive analysis of the product’s operational properties formation considering machining technology

Stupnytskyy Vadym, Hrytsay Ihor

Archive of Mechanical Engineering

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2020

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LXVII, nr 2

149--167

EN

Product Lifecycle Management (PLM) system requires consideration and ensuring efficient operating conditions for the most loaded parts in the product, not only at the product’s design stage, but also at the production stage. Operational properties of the product can be significantly improved if we take into consideration the formation of the functional surfaces wear resistance parameters already at the planning stage of the technological process structure and parameters of the product’s machining. The method of constructing predictive models of the influence of the technological process structure on the formation of a complex of product’s operational properties is described in the article. The relative index of operational wear resistance of the machined surface, which is characterized by the use of different variants of the structure and parameters of this surface treatment, depends on the microtopographic state of the surface layer and the presence of cutting-induced residual stress. On the example of the eject pin machining it has been shown how the change in the structure of the manufacturing process from grinding to the turning by tool with the tungsten carbide insert affects the predicted wear resistance of the machined functional surface.

4

Improved method of gear hobbing computer aided simulation

Hrytsay Ihor, Stupnytskyy Vadym, Topchii Vladyslav

Archive of Mechanical Engineering

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2019

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Vol. LXVI, nr 4

475--494

EN

Simulation studies of the hobbing process kinematics can effectively improve the accuracy of the machined 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 proposed method is more appropriate, since the algorithm for the momentary 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.