Yip Wai Sze, To Suet
State Key LaDepartment of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
Micromachines (Basel). 2019 Mar 31;10(4):231. doi: 10.3390/mi10040231.
The material swelling effect in single point diamond turning (SPDT) causes ragged materials on a machined surface which slows down the movements of tool tip vibration, and acts as a simple impacted pendulum system with a damping effect and displays a single twin peak in fast Fourier transform (FFT). Due to the low elastic modulus and low thermal conductivity of titanium alloys, the material swelling effect of titanium alloys in SPDT is much more serious than that of traditional metals. For this reason, the tool tip vibration in SPDT of titanium alloys is expected to be different from previous reports. In this study, apart from the demonstration of the original single twin peak induced from the material swelling effect by the main cutting motion, we reported recently that there exists another twin peak induced by secondary material swelling arising from the movement of tool tip vibration in the SPDT of titanium alloys. The additional twin peak was located at the right side of the original twin peak in FFT, displaying two twin peaks in the frequency domain of cutting force and suggesting the existence of another tool tip vibration system with a new damping factor in the SPDT of titanium alloys. Combining the effects of primary and secondary material swelling, the new dynamic model with the modified damping factor of tool tip vibration system are developed, which surface roughness of the machined titanium alloys in SPDT was predicted in higher accuracy by using the new model. The FFT of cutting force, surface roughness, and surface profile were provided in this article for the experimental validations.
单点金刚石车削（SPDT）中的材料膨胀效应会导致加工表面出现参差不齐的材料，这会减缓刀尖振动的运动，并作为一个具有阻尼效应的简单冲击摆系统，在快速傅里叶变换（FFT）中显示出单个双峰。由于钛合金的弹性模量低和热导率低，钛合金在SPDT中的材料膨胀效应比传统金属严重得多。因此，钛合金在SPDT中的刀尖振动预计与以前的报道不同。在本研究中，除了证明主切削运动引起的材料膨胀效应产生的原始单双峰外，我们最近还报道，在钛合金的SPDT中，刀尖振动的运动还会引起二次材料膨胀，从而产生另一个双峰。额外的双峰位于FFT中原始双峰的右侧，在切削力的频域中显示出两个双峰，这表明在钛合金的SPDT中存在另一个具有新阻尼因子的刀尖振动系统。结合一次和二次材料膨胀的影响，建立了刀尖振动系统阻尼因子修正后的新动态模型，利用该新模型可以更高精度地预测钛合金在SPDT中的加工表面粗糙度。本文提供了切削力、表面粗糙度和表面轮廓的FFT用于实验验证。
