低频振动刀具结构对CFRP/TC4叠层结构制孔质量影响

Effect of Cutting Tools of Low-frequency Vibration on Hole-makingQuality of CFRP/TC4 Laminates

合适的刀具几何形状对于提升CFRP/TC4叠层结构低频振动加工孔质量尤为关键,本文研究并分析了双刃麻花钻、三刃麻花钻、二级阶梯钻和平底钻四类刀具在低频振动钻孔中对CFRP/TC4叠层结构制孔过程和孔加工质量的影响。相关实验结果表明:在切削过程中,阶梯钻展现出的切屑形态具有显著的两段式特征,即切屑宽度从细到粗变化,形状则由扇形过渡到锥形,且阶梯钻产生的切屑相对较小,有利于排屑时带走热量;麻花钻所形成的切屑展现出扇形单元状的规则形态,其边缘保持完整,该切屑特性不仅使排出过程更为顺畅,还能有效即时带走加工过程中产生的热量,从而减少切屑在排出时对孔壁造成二次损伤的风险;使用麻花钻和阶梯钻时的最高加工温度分别为117℃和105℃,阶梯钻结构设计显著降低了加工时的切削阻力和摩擦,有助于降低钻削温度;由于阶梯钻采用钻—扩—铰一体化设计,使用阶梯钻加工钛合金材料孔时在入口和出口直径上表现出更高的一致性,孔径误差相对较小,更接近刀具的名义直径。

The appropriate tool geometry is particularly critical for improving the low-frequency vibration machining hole quality of CFRP/TC4 laminated structures,so this paper studies and analyzes the effects of four types of tools,including double-flute spade drill,three-flute spade drill,two-flute stepped drill,and flat bottom drill,on the hole-making process and hole machining quality in the low-frequency vibration drilling process of CFRP/TC4 laminated structures.The relevant experimental results show that,the chips formed by the stepped drill exhibit a significant two-stage feature,i.e.,the change in chip width from fine to coarse,and the shape is transitioning from a fan shape to a cone shape during cutting.Moreover,the chips generated by the stepped drill are relatively small,which is conducive to chip evacuation and heat dissipation.The chips formed by the spade drill exhibit a regular fan-shaped unitary shape,with the edge remaining intact.This chip characteristic not only makes the evacuation process smoother but also effectively dissipates heat generated during machining,thereby reducing the risk of secondary damage to the hole wall caused by chip evacuation.The highest machining temperature when using a spade drill and a stepped drill is 117℃and 105℃.The stepped drill structure design significantly reduces cutting resistance and friction during machining,which helps reduce machining temperature.When dealing with titanium alloy materials,the stepped drill's design of drilling,enlarging,and reaming in one step results in a higher degree of consistency in the diameter of the hole at the entrance and exit,with a smaller relative error in the hole diameter and a closer approach to the nominal diameter of the tool.