车削大螺距螺纹刀具后刀面磨损宽度分布特性

摘要

In turning large pitch thread,the features of process scheme are low speed,large cutting depth and feeding. There is obviously uneven wear on the left and right rear faces. It will directly affect the processing quality consistency and processing efficiency of left and right threaded surface. The existing methods of meas-uring wear width on rear face only reflect the average properties of wear width on rear face changing with cut-ting stroke,unable to reveal the distribution characteristics of wear width on rear face. To this end,a tool is designed and manufactured which can turn trapezoidal external thread which pitch is 16 mm. The experiment of wear on left and right rear faces is carried out by using isoparametric axial stratified cutting. The analyzing wear characteristics and constructing the distribution function of wear width on rear faces show that the wear widths of left and right rear faces exhibits different distribution characteristics in the length direction of cutting edge and cutting stroke direction,and the wear on left rear faces is more obvious. The above method can be used to describe quantitatively the wear condition of rear faces in turning large pitch thread,and evaluate the difference of wear between left and right rear faces under different cutting strokes.%采用低速、大切深、高进给工艺方案车削大螺距螺纹时,刀具左右后刀面存在明显不均匀磨损,直接影响左右螺纹面的加工质量一致性和加工效率.已有的刀具后刀面磨损宽度测量方法仅反映出后刀面磨损宽度随切削行程变化的平均性质,无法揭示后刀面磨损宽度的分布特性.为此,设计和制磨出一把用于车削螺距16 mm梯形外螺纹的刀具,采用等参数轴向分层切削方法进行左右后刀面磨损实验,分析刀具后刀面磨损特征,构建刀具后刀面磨损宽度分布函数,揭示出后刀面磨损宽度分布特性.结果表明:左右后刀面磨损宽度在切削刃长度和切削行程两个方向上均呈现不同的分布特性,且左后刀面磨损明显大于右后刀面磨损,上述方法可用于定量描述车削大螺距螺纹刀具后刀面磨损状态,评定不同切削行程条件下刀具左右后刀面磨损的差异性.