A. I. SagradyanUDC 621.902.31With the method of mathematical planning, the character and the degree of influence of the parameters of cutting regimes of the corresponding cutting forces in machining steels and alloys differing in physicochemical properties have been investigated. The dependence of the corresponding cutting forces on the change in the cutting regimes has been obtained. The optimum force characteristics have been found experimentally as a result of choosing the most favorable cutting regimes.The character and the degree of influence of the parameters of cutting regimes on the cutting-force components in machining steels and alloys differing in their physicochemical properties (steel 45, 2Kh13, R18, VT5) with cutting tools from speed-cutting alloys V14M7K25 have been investigated using the method of mathematical planning of the experiment [1-4], which has made it possible to obtain the dependence of the corresponding forces on the change in the cutting regimes. On the basis of the experiments, the power dependences of the cutting-force components on the feed rate and depth in a wide range of change in the cutting regimes have been obtained.The values of the cutting-force components obtained by such a method in such a wide range of cutting regimes can be used both for comparative evaluation, in particular, in machining one steel with different tool materials, and for various materials with cutting tools from the speed-cutting alloy V14M7K25.Not only does this method permit quick and fairly exact determination of the values of the cutting-force components, but it also makes it possible to achieve a marked decrease in the consumption of the material being machined and the tool material.The experiments were performed on a 1K62 machine tool equipped with a VR-1 variable-speed drive. The output signals were obtained with the aid of a UDM-1 three-component dynamometer with subsequent recording through a TA-5 amplifier by a K-105 oscillograph.Mathematical planning was carried out in accordance with [3, 4] for a complete factorial experiment of the type of 3 3 with splitting of the plan into three blocks with nine combinations of conditions in each. In this case, one can distinguish 13 effects with two degrees of freedom each: VSt; VS, VS 2 , Vt, Vt 2 , St; St 2 , V 2 St; VS 2 t; VSt 2 and VS 2 t 2 , V 2 S 2 t, V 2 St 2 .Mixing VSt 2 interactions with the three blocks, we getThe blocks have the following form:0 000 011 022 101 112 120 210 221 202 L = 1 100 111 122 201 212 220 010 021 002 L = 2 200 211 222 001 012 020 110 121 102If only one of these blocks, e.g., L = 1, is realized, then the plan of the 3 3 factorial experiment third-replicate will take on the form given in Table 1.The values of V m , S m , and t m can be determined by the formulas proposed in [4]:
The influence of shear stresses on the physical processes proceeding on the surface of contact of a cutting tool with a chip removed has been investigated. The mechanisms of appearance of contact layers and the dependence of the lengths of the elastic and plastic parts of these layers on the normal and shear stresses in the contact zone have been considered. It was established that a natural "white" layer formed in the process of cutting plays a protective role and, as a consequence, decreases the rate of wear of the tool.The physical effects in a contact zone were investigated in [1][2][3][4]. It is known that the properties of materials subjected to high-rate deformations differ from the properties of materials tested under static conditions. In [1-3], it was shown that the contact zone formed in the process of cutting is divided into two parts, one of which is elastic and the other of which is plastic (Fig. 1). It was also established that the lower contact chip layers move with zero velocities along the frontal surface of a tool in the plastic-contact region. In the elastic-contact region (0 < x < (C − C 1 )), the shear stress τ F change in proportion to the normal stress:1580 H . The stress σ M was calculated for r = C = 2 mm. The quantity C was determined experimentally with an MMI-2 instrumental microscope. For the regime of cutting where V = 65 m/min, S = 0.30 mm/rot, t = 2.0 mm, β = 30 o , γ = 10 o , a = 21 mm, and b = 2.83 mm, we obtained ξ = 2.95 and µ = 0.8. Consequently, σ M = 1828 MPa. The coefficient n was determined from the expression [1] n = 2 C aξ [µ + tan (β − γ)] − 1 and was equal to n = 3.54 for the conditions of our experiments. By using the values of σ M and n we can construct a diagram of distribution of normal contact stresses over the frontal surface of a cutting tool. The normal and tangential forces in the contact zone were determined from the relation [2] N = P z cos ω cos (ω + γ) = 1580 H , F = P z cos ω (sin ω + γ) = 1328 H , µ = F ⁄ N = 0.8 .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.