Determination of the Shear Angle in the Orthogonal Cutting Process

Abstract

Determination of the shear angle by experimental and analytical methods, as well as by numerical simulation, is presented. Experimental determination of the shear angle was performed by analyzing the chip roots obtained by the method of cutting process quick stop through purposeful fracture of the workpiece in the area surrounding the primary cutting zone. The analytical determination of the shear angle was carried out using the chip compression ratio and was based on the principle of a potential energy minimum. Measurement of the shear angle in the numerical simulation of orthogonal cutting was performed using the strain rate pattern of the machined material at the selected simulation moment. It was analyzed how the parameters of the Johnson–Cook constitutive equation and the friction model affect the shear angle value. The parameters with a predominant effect on the shear angle were determined. Then the generalized values of these parameters were established with a software algorithm based on identifying the intersection of the constitutive equation parameter sets. The use of generalized parameters provided the largest deviation between experimental and simulated shear angle values from 9% to 18% and between simulated and analytically calculated shear angle values from 7% to 12%.

Improvement of Analytical Model for Oblique Cutting—Part I: Identification of Mechanical Characteristics of Machined Material

“…A constitutive equation with such parameter values should describe the mechanical properties of the machined material for a certain (predetermined) region for different cutting conditions, cutting modes, tool geometric parameters, etc. [111,112]. A flowchart of the algorithm for determining the generalized parameters of the constitutive equation and implementation of machined material mechanical properties in the calculation algorithm of the analytical cutting model is shown in Figure 4.…”

“…The fourth step of the developed algorithm is devoted to specifying the previously defined parameter values by numerical simulation of the oblique cutting process using the developed finite element cutting model (see Section 3.2.2). This step generalizes these parameters to a certain range for different values of cutting conditions and modes, as well as tool geometric parameters [111,112]. According to the constitutive equation with generalized parameters, the mechanical properties of the machined material at known values of strain, strain rate, and temperature are determined.…”

“…2). This step generalizes these parameters to a certain range for different values of cutting conditions and modes, as well as tool geometric parameters [111,112].…”

“…The process characteristic-the cutting force component F X -was used as an objective value of the cutting process characteristics to determine the required parameters. For the determination of the constitutive equation's generalized parameters, the methodology described in [111,112] was used. The values of the generalized parameters determined from the numerical simulation of the oblique cutting process are presented in Table 4.…”