大直径镶片式扁钻与传统的扁钻相比，结构上有了很大的改进，切削性能获得了较大的提高，已开始批量地应用于CNC机床．扁钻加工中主切削刃为沿半径方向前角，刃倾角和切削速度均变化的斜角切削．把主切削刃的斜角切削看作是一系列宽度狭窄的斜角切削排列起来，从而推导出主切削刃的总切削功率为包含切屑流屑角的函数表达式．应用切屑沿切削功率最小方向流出的原理和数值分析的方法求出流屑角．计算的流屑角与试验测量结果是相吻合的． Compared with the traditional flat diamonds, the large diameter flat diamonds have been greatly improved in structure and the cutting performance has been greatly improved. The large-diameter flat diamonds have been used in mass production in CNC machines. The main cutting edge of the flat diamond machining is bevel cutting along the radial direction of the rake, cutting edge inclination and cutting speed changes. The bevel cutting of the main cutting edge is considered as a series of bevel cutting with a narrow width. Thus, the total cutting power of the main cutting edge is deduced as a function expression including the chip flow angle. The chip flow angle is calculated by the principle of chip flow along the minimum cutting power and numerical analysis. The calculated fluff angle is in agreement with the experimental measurement.