CFRP/钛合金叠层构件钻孔刀具制孔质量对比研究

Comparison Study on Machining Property of Drilling Tools for CFRP/Titanium Alloy Laminated Structures

钛合金与碳纤维增强复合材料(Carbon-fiber reinforced plastics,CFRP)均广泛应用于航空航天领域。钛合金/复合材料构成的叠层构件对钻孔刀具提出了更高的要求。试验采用两种不同"变顶角"结构的钻头进行了钛合金/CFRP叠层构件钻孔实验。并对比分析了两种刀具加工孔的表面质量和切削力。结果发现:顶角由小变大的钻头轴向力较大,出口质量较差,但转矩小,孔径精度高,孔壁质量好;而顶角由大变小的钻头转矩较大,孔壁质量较差,但轴向力小,能有效抑制出口毛刺和撕裂,减小CFRP层孔的圆柱度误差。因而在加工以复合材料为出口的叠层构件时,顶角由大变小的钻头更具有优势。

Titanium alloy and carbon fiber reinforced plastic（ CFRP） are both wildly used in aerospace industries.The hole-making process for titanium alloy/composite materials laminated structure has higher requirements for the drilling tools. In this paper,two different ＂changed point angle＂ drill bits were used to investigate the effect of the point angle on the cutting force and quality of holes. The results show that S-L type drill（ the point angle change from small to large） presents the higher axial cutting force and poor quality in hole exit,but lower torque and higher dimensional accuracy. For the L-S type drill（ the point angle change from large to small）,it presents the higher drilling torque and bad machining quality of hole surface,but lower axial cutting force and burrs/tears in hole exit. Meanwhile,the L-S type drill can also provide better cylindrical form tolerance in CFRP layer. Therefore,L-S type drill has more advantages in drilling process of titanium alloy/CFRP laminated structure when CFRP layer is in the bottom of the stack.