Distribution Characteristics of Machined Surface Roughness in Turning Large Pitch Thread

• 1、National & Local United Engineering Laboratory of High Efficiency Cutting and Tools, Harbin University of Science and Technology, Harbin 150080
• 2、Qiqihar Second Machine Tool(Group) Co.,Ltd.,Qiqihar 161005

Abstract：Machined surface roughness of large pitch thread constantly changes along the axial direction. It has important influence on screw drive accuracy and stability. The processing method of left and right cutting edges axial stratified cutting is adopted, to conduct large pitch thread experiment. In the experiment, the distribution characteristics of large pitch thread machined surface roughness is revealed by changing the parameters, which include cutting edge structure, feeding order and machining allowance. 10 sample pieces which has equal distance are extracted along the axial direction, the sample piece distance is equal to pitch. To get the distribution characteristics curves of the surface roughness of the left and right thread surface, sample piece thread surface roughness is tested perpendicular to the cutting speed direction. To judge the general level, the range of fluctuation and the degree of dispersion of the left and right thread surface roughness distribution, the average value of surface roughness, variable range and standard deviation are used. The consistency of surface roughness distribution and its influencing factors under different cutting conditions are analyzed. The process design scheme of left and right thread surface is proposed, which is based on consistency of the surface roughness.

Keywords： External thread large pitch axial stratified cutting machined surface roughness distribution characteristics