Effect of Milling Cutter Helix Angle and Cutting Parameters on Surface Roughness in Peripheral Milling: A Critical Review and Theoretical Framework

Abstract

Surface roughness in peripheral milling results from the coupled effects of cutting conditions, tool geometry, machine–tool dynamics, tool condition, runout, and the kinematic envelope generated by successive cutting edges. Among cutter-geometry variables, helix angle is particularly important because it changes the axial phase distribution of the cutting edge, chip-thickness distribution, cutting-force components, and dynamic excitation. This paper presents a critical review and theoretical analysis of the influence of helix angle and cutting parameters on surface roughness in peripheral milling. No new experimental measurements are claimed. Instead, published experimental, analytical, numerical, and prediction studies are synthesized into a unified mechanistic framework linking helix angle to chip thickness, cutting force, dynamic response, surface topography, and roughness. The literature indicates that feed per tooth is generally a dominant geometric/process variable, whereas cutting speed and depth of cut affect roughness through coupled force, thermal, wear, and dynamic mechanisms. Helix angle should therefore not be treated as an isolated parameter or associated with a universal optimum value. Its effect depends on cutter diameter, tooth count, workpiece material, engagement, feed per tooth, cutting speed, tool stiffness, runout, and dynamic stability. The proposed framework is explicitly presented as a literature-derived theoretical structure and a basis for future experimental calibration and validation.