Abstract

Serrated chip is a typical characteristic of high-speed cutting. It is an important aspect of high-speed cutting mechanism, and has significant influence on cutting force, cutting temperature and tool wear. For the observation of serrated chip, optical microscope (OM) and scanning electron microscope (SEM) are usually used. The main problem of OM observation is time-consuming and that of SEM observation is high cost. Therefore, a new serrated chip observation method based on digital microscope（DM）was proposed. The advantage of this method is that the experimental chip can be observed directly, so plenty of preparation time of metallographic sample is saved, and the cost of it is also lower. Relevant parameters, including segment spacing, tooth top height and tooth root height, can be measured by depth synthesis function. This will greatly facilitate the quantitative study of serrated chip, and thus promote the in-depth study of high-speed cutting. The validity of the proposed method was verified by comparing the observation results of OM and DM. The advantages and disadvantages of the proposed method were also discussed. Furthermore, the serrated chips in high-speed cutting of Ti6Al4V alloy and AISI 1045 steel were studied. The results show that whether it's Ti6Al4V alloy or AISI 1045 steel, the degree of segmentation increases with the increase of cutting speed and depth of cut, and decreases with the increase of rake angle. The segment spacing decreases with the increase of cutting speed and rake angle, but increases with the increase of depth of cut. The mechanism of serrated chip changing with cutting parameters was analyzed based on adiabatic shear theory.

摘要

锯齿状切屑是高速切削的典型特征。这是高速切削机构的重要方面，对切削力，切削温度和刀具磨损具有重要影响。为了观察锯齿状芯片，通常使用光学显微镜（OM）和扫描电子显微镜（SEM）。OM观测的主要问题是耗时，而SEM观测的主要问题是成本高。因此，提出了一种新的基于数字显微镜（DM）的锯齿状芯片观察方法。该方法的优点是可以直接观察实验芯片，节省了金相样品的大量制备时间，成本也较低。可以通过深度综合功能测量相关参数，包括节距，齿顶高度和齿根高度。这将极大地促进锯齿状切屑的定量研究，从而促进对高速切削的深入研究。通过比较OM和DM的观测结果，验证了该方法的有效性。还讨论了该方法的优缺点。此外，还研究了Ti6Al4V合金和AISI 1045钢的高速切削中的锯齿状切屑。结果表明，无论是Ti6Al4V合金还是AISI 1045钢，分段度随着切削速度和切削深度的增加而增加，而随着前角的增加而减小。分段间距随着切削速度和前角的增加而减小，但是随着切削深度的增加而增大。