硬质合金刀片复杂刃口的柔性纤维辅助力流变钝化抛光试验研究

Experimental study on flexible fiber assisted stress rheological passivation and polishing of complex edge of cemented carbide insert

为实现硬质合金刀片复杂形状刃口的一致性钝化,提升刀片使用性能和寿命,采用柔性纤维辅助力流变抛光方法,利用非牛顿流体在剪切应力作用下的流变特性和柔性纤维的控流作用,对硬质合金刀片复杂形状刃口进行抛光。以刃口钝圆半径偏离值K为评价指标,用田口法分析抛光转速、纤维密度、纤维与刀片接触长度等工艺参数对刃口钝圆半径及其一致性的影响,并采用方差分析法评估各因素的权重,综合抛光参数对不同位置切削刃的影响,得到的最优工艺参数组合为纤维密度为200~250根/cm^(2),接触长度为4 mm,抛光转速为55 r/min。在最优工艺参数组合下抛光10 min,7个切削刃的钝圆半径均能达到(50.0±5.0)μm的钝化要求,且其切削刃表面粗糙度R;从(118.00±10.00) nm降至(9.35±0.75) nm,刃口完整无缺陷。

To obtain the high consistency passivation of cutting edge of the cemented carbide insert with complex shape and improve the tool performance and life, the flexible fiber assisted stress rheological polishing method, which utilizes the rheological properties of non-Newtonian fluid under shear stress and the flow control effect of flexible fibers, was proposed to polish the complex shape edge of cemented carbide insert. The deviation value K of the passivation radius of the cutting edge was used as the evaluation index, and Taguchi method was employed to analyze the effects of the polishing speed, the fiber density and the fiber-insert contact length on the edge passivation radius and its consistency. The weight of each factor was evaluated by variance analysis method, and the optimal process parameters were obtained by combining the influence of the polishing parameters on the cutting edge at different positions. The optimal combination of process parameters is that the fiber density is 200 to 250 fibers/cm^(2), the contact length is 4 mm and the polishing speed is 55 r/min. Under the optimal combination of process parameters, the passivation radius of seven cutting edges can reach(50.0 ± 5.0) μm after polishing for 10 min, the surface roughness Ra of the cutting edges are reduced from(118.00 ± 10.00) nm to(9.35 ± 0.75) nm and the cutting edge is complete and free of defects.