根据非自由切削模型和切削试验研究了切屑流动的分叉突变原理，结果表明：在切削层图形系数ｇｓ＝１的两侧有两个分叉点ｇｓ１和ｇｓ２，形成一个分叉区间（ｇｓ１，ｇｓ２）；单位切削功率的连续多极值取向是切屑流动分叉的原因；在分叉区间切屑流动状态的改变呈现出典型的尖点突变特征；突变的滞后性对切削力及切屑旋向有明显的影响。 The principle of bifurcation and catastrophe of the chip flow is studied based on the non-free cutting model and the cutting test. The results show that there are two bifurcation points gs1 and gs2 on both sides of the gs = 1, forming a bifurcation interval (gs1, gs2). The continuous multi-pole orientation of cutting power per unit is the reason for the bifurcation of the chip flow. The change of the chip flow state in the bifurcation section shows typical cusp mutation characteristics. Obvious impact.