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40 ISCAR MILLING CALCULATIONSCutting Forces, Cutting Torque, and Power ConsumptionDuring the cutting process, each tooth of a mill that comes into contact with the machined material experiences a counteracting force, which prevents material removal. As a result, these teeth are subjected to appropriate forces. The total (or resultant) cutting force (F) is the vector sum of these forces and is typically resolved into the following three components:%u2022 Tangential or circumferential cutting force (Ft), directed tangentially to the outer contour of a mill,%u2022 Radial cutting force (Fr), acting along the mill radius,%u2022 Axial cutting force (Fa), directed toward the mill axis.F= %u221aFt2+Fr2+Fa2 (M7)The force action diagram depends on the type of a mill and the milling method.Fig. 29 illustrates cutting forces acting on a face mill.In milling, the tangential cutting force (Ft) is responsible for the primary work required to remove machined material. This force is crucial for calculating the necessary torque and power consumption of the machine%u2019s main drive, as well as determining the strength of the drive elements. The axial cutting force (Fa) determines the load exerted on the spindle bearings in the axial direction. In addition, this force is used for buckling analysis of the mill, particularly when dealing with high mill overhang.The radial cutting force (Fr) pushes a mill away from a workpiece. In peripheral (slab) milling, this force causes bending of the arbor that carries the mill. On the other hand, in face and end milling, the bending force (Fb) is the combined effect of the tangential force (Ft) and the radial force (Fr) (Fig. 30). These bending forces serve as the initial data for the bending analysis of either the arbor or the mill body, depending on the case.Fig. 30. Cutting forces in face milling.The bending force (Fb) can be decomposed into two components in another manner, with one of the components acting in the direction of the feed motion. This particular component is essential for the engineering analysis of a machine%u2019s feed drive.There are various methods available for calculating cutting forces. Some rely on empirical equations that incorporate parameters such as depth of cut, width of cut, mill diameter, and coefficients and power exponents, which are selected based on different factors. Alternatively, simpler methods involve calculating the tangential force (Ft) using a specific cutting force (kc1) and the average chip thickness (hm).The specific cutting force (kc1) is a force determined through experimentation, representing the force required to remove a chip area of 1 mm2 (.0016 in2) with aFrFaFbFt