钛板刚度对钻削轴向力和出口毛刺的影响

针对弱刚性钛合金薄板钻削过程，从理论和实验两方面研究工件刚度对轴向力和出口毛刺的影响规律。考虑工件变形与轴向力的相互影响，建立弱刚性钛板钻削轴向力预测模型，求解工件变形带来的附加进给率，结合提出的毛刺厚度预测方法和高度累积判定式，实现工件刚度的影响规律分析，并设计以刚度和进给率为变量的钻削实验。实验结果表明，随着工件刚度的减小，轴向力曲线上升段延长、下降段缩短，最大值略微减小；而毛刺高度减小、厚度增加，类型从冠状变为均匀状。轴向力预测曲线与实验曲线趋势相符，峰值预测误差在8%以内；毛刺尺寸和类型的理论分析结果与实验结果具有一致性。工件刚度以改变实际进给率的方式影响钻削过程，因此弱刚性钛板钻削出口毛刺的抑制要综合考虑工件刚度的影响。

Influence of stiffness on thrust force and exit burr in drilling titanium plates

For drilling process of thin titanium plates, the influence of workpiece's stiffness on thrust force and exit burr is investigated experimentally and theoretically. The interaction of workpiece's bending and thrust force has been studied. Additional feed rate caused by bending of workpiece could be obtained through differential of deflection. Then, a model is developed to predict thrust force for plates with low stiffness. Equations for burr thickness calculation and burr growth deciding are also established to analyze the influence of stiffness on burr type and size. Drilling experiments are conducted with varying stiffness and feed rate. Experimental results show that with the decrease of workpiece stiffness thrust force rises slowly, descends quickly, the maximum value decreases slightly; while, burr type changes from crown to uniform, and burr becomes lower and thicker. Predicted curve of thrust force has the same trend with the experimental curves. Predicted errors of maximum values are within 8%. Analytical results of burr type and size agree with the experimental results. Stiffness affects drilling process through changing the actual feed rate, thus stiffness should be considered to control burr in drilling titanium plates with low stiffness.