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,inclu-ding 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 charac-teristic 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 tempera-ture when using a spade drill and a stepped drill is 117℃and 105℃.The stepped drill structure design significantly re-duces cutting resistance and friction during machining,which helps reduce machining temperature.When dealing with tita-nium 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 clos-er approach to the nominal diameter of the tool.
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