碳纤维复合材料/钛合金叠层板振动辅助钻孔技术

碳纤维复合材料(Carbon fiber reinforced plastic,CFRP)/钛合金(Titanium alloy,Ti)叠层板材料两种材料加工性能差异极大,且钛合金导热系数和弹性模量低,极易产生高温螺旋长屑,不仅会影响自身孔表面质量,也会划伤和热损伤碳纤维复合材料层,这是该材料加工的主要难点。本文搭建了超声-低频振动钻孔试验台,在切削温度、钻孔质量和切屑形态等几个方面,对普通、旋转超声和轴向低频振动辅助等3种钻孔方式进行了对比分析,并对钛合金切屑造成的CFRP层损伤进行了机理探索。研究表明:相比普通钻孔,引入旋转超声和轴向低频振动可降低钻孔温度,提高钻孔质量。特别是轴向低频振动辅助钻孔方式,可有效打断钛合金切屑,切削温度比普通钻孔方式降低约45%,减轻了钛合金切屑对CFRP层的损伤,提高了钻孔质量。

Vibration Assisted Drilling of Carbon Fiber Reinforced Plastic and Titanium Stacks

CFRP/Ti stacks have been widely used in aviation industry. Mechanical characteristics of Carbon fiber reinforced plastic (CFRP) is greatly different from that of the titanium alloy. The low thermal coefficient and elastic modulus of Titanium alloy lead to long spiral chips with high temperature during drilling which may cause surface scratches of machined hole and damages to the CFRP layer. In the paper three types of drilling methods:conventional drilling, rotary ultrasonic assisted drilling and low-frequency vibration assisted drilling are compared and analyzed from the following points of view:Cutting temperate, drilling quality and chip morphology. It is shown that compared with conventional drilling, both the ultrasonic vibration and low frequency vibration assisted drilling could reduce the temperature and improve the drilling quality. The low frequency vibration assisted drilling method could break the cutting chips belts of titanium alloy material to small chips. Due to the reason, the cutting temperature could be reduced by 45%. As a result, the CFRP damages caused by over heated cutting chips belts of titanium alloy could be avoided, and the drilling quality could be improved to a great deal.