Improvement effects of vibration on cutting force in rotary ultrasonic machining of BK7 glass
Improvement effects of vibration on cutting force in rotary ultrasonic machining of BK7 glass
复制标题
BK7玻璃旋转超声加工中振动对切削力的改善作用
DOI：
10.1016/j.jmatprotec.2013.04.001
复制
发表时间：
2013-09-01
影响因子：
6.3
通讯作者：
Wu, Xiangchao
中科院分区：
文献类型：
--
作者：
Lv, Dongxi;Huang, Yanhua;Wu, Xiangchao
旋转超声加工 (RUM) 具有显着降低切削力的巨大潜力，切削力与刀具磨损、加工精度、加工温度和表面完整性直接相关。然而，超声振动对切削力的改善机制尚未得到充分认识，限制了目前进一步降低RUM过程中切削力的优化方法。本研究结合磨料运动学原理，首先根据压痕力学理论讨论了加载阶段材料应变率的演化特征。考虑到这些特征，在不同工艺参数下对抛光样品表面进行了 RUM 划痕测试，以捕获高应变率阶段引起的综合损伤模式。接下来，分别对RUM划痕和温和抛光表面进行对比压痕测试。对压痕引起的损伤结构和载荷-位移曲线进行了表征和评估，以研究叠加超声波对正式 RUM 工艺中切削力的改进机制。研究发现，叠加超声波振动会导致初始裂纹在磨料加载阶段成核，并且它们的扩展会增加正式 RUM 工艺中获得的材料去除率 (MMR)。此外，初期裂纹对压痕力提供了屏蔽作用，这是降低金刚石工具切削力的主要因素。初始裂纹的成核导致磨料渗入材料的硬质基底后产生更多的能量耗散，这将导致最终 RUM 表面上产生更高的残余应力。此外，还针对材料的应变率效应开发了磨料加载阶段涉及的失效模式（塑性变形或脆性断裂）演化模型。 (c) 2013 Elsevier B.V. 保留所有权利。
Rotary ultrasonic machining (RUM) exhibits a high potential for a significant reduction in the cutting force, which directly associates with tool wear, machining accuracy, machining temperature, and surface integrity. However, the improvement mechanisms of the ultrasonic vibration on the cutting force are still not fully recognized, restricting the currently optimization methods for further reducing the cutting force occurred during the RUM process. In this research, by incorporating the kinematics principles of the abrasive, the evolution features of the material strain rate in the loading phase were first discussed with respect to the indentation mechanics theory. Taking these features into account, the RUM scratching tests were carried out on the polished specimen surfaces under various process parameters to capture the integrated damage patterns evoked in the high strain rate stage. Following, the comparative indentation tests were respectively conducted on the RUM scratches and the gentle polished surfaces. The indentation-induced damage structures and the load-displacement curves were characterized and assessed to investigate the improvement mechanisms of the superimposed ultrasonic on the cutting force in formal RUM process. It was found that superimposing an ultrasonic vibration led to the incipient cracks nucleated in the abrasive loading phase, and their propagations would increase the material removal rate (MMR) obtained in formal RUM process. Furthermore, the incipient cracks provided a shielding effect to the indentation force, which was a dominant factor in diminishing the cutting force of the diamond tool. The nucleation of the incipient cracks resulted in more energy dissipation after the abrasives penetrating into the hard substrate of the material, which would lead to a higher residual stress on final RUM surface. In addition, a failure pattern (plastic deformation or brittle fracture) evolution model involved in abrasive loading phase was developed with respect to the strain rate effects of the material. (c) 2013 Elsevier B.V. All rights reserved.