Mechanism for material removal in ultrasonic vibration helical milling of Ti-6Al-4V alloy
Mechanism for material removal in ultrasonic vibration helical milling of Ti-6Al-4V alloy
复制标题
Ti-6Al-4V合金超声振动螺旋铣削的材料去除机理
DOI：
10.1016/j.ijmachtools.2018.11.001
复制
发表时间：
2019-03-01
影响因子：
14
通讯作者：
Li, Shipeng
中科院分区：
文献类型：
--
作者：
Chen, Guang;Ren, Chengzu;Li, Shipeng
航空工业中钛合金、复合材料、飞机蒙皮等难加工材料的应用，迫切需要高质量的制孔技术。为提高孔加工质量，采用超声振动螺旋铣削（UVHM）技术加工Ti-6Al-4V合金，并与常规螺旋铣削（HM）工艺进行对比试验。通过对UVHM切削轨迹的建模和对底部切削刃和周边切削刃的刀-工件接触行为的分析，研究了UVHM的材料去除机理。采用理论与实验相结合的方法确定了UVHM的实际振动频率。由于UVHM中的振动，底部切削刃与工件产生不连续接触。建立了考虑材料去除的单元力模型，并应用于轴向力减小分析。在不同的切削速度下，UVHM的轴向切削力比HM降低了38-64%。周向切削刃的切削速度呈周期性变化。由于轴向振动，切削刃可以与切屑分离，这将有助于降低切削力和改善散热。同时，周边切削刃产生摩擦效应，可改善微尺度表面粗糙度。由于周期性摩擦和超声振动压缩的影响，UVHM增加了85%和99%的表面压应力在孔表面的轴向和周向方向，分别。
High quality hole-making technology in the aviation industry is urgently needed due to the application of difficult-to-cut materials, such as titanium alloy, composite materials and the stacks in aircraft fuselage skins. To improve the hole-making quality, an ultrasonic vibration helical milling (UVHM) technology was developed for machining of Ti-6Al-4V alloy, meanwhile, comparison experiments were conducted between UVHM and conventional helical milling (HM) processes. Material removal mechanism of UVHM was investigated by modeling of cutting trajectories and the analysis of tool-workpiece contact behavior for bottom and peripheral cutting edges. The actual vibration frequency in UVHM was also determined by a theoretical-experimental combined method. Due to the vibration in UVHM, the bottom cutting edges generate discontinuous contact with workpiece. Unit forces considering material removal were modeled and applied to analyze the axial force reduction. The axial cutting forces of UVHM were reduced by 38-64% compared with HM at different cutting speeds. The cutting speed of peripheral cutting edge changes periodically. The cutting edges can separate with chips due to axial vibration, which will contribute to reducing the cutting forces and improving heat dissipation. Meanwhile, a friction effect was generated by the peripheral cutting edge which can improve the micro-scale surface roughness. Due to the effects of periodical friction and compression by ultrasonic vibration, UVHM increases the surface compressive stresses by 85% and 99% at the hole surface for axial and circumferential directions, respectively.