Search

This paper aimed to obtain the elastic recovery value of the machined surface of the workpiece in the milling process of titanium alloy, because it can cause strong friction between the tool flank and the workpiece surface. A new online measurement system was designed to monitor the elastic recovery behavior of Ti6Al4V alloy in dry milling based on the digital image correlation (DIC). DIC measurement principle was intuitively analyzed by means of picture illustration. The orthogonal milling experiments were designed with different cutting parameters and the experiment processes were designed in detail, including the installation of DIC measurement system, the speckle disposal of the measured surface and the field calibration of test instrument. The displacement curve of the target region was analyzed according to the material deformation characteristics of metal materials in the cutting process and thus the calculation method of elastic recovery value of machined surface was obtained. Besides, the optimization method of cutting parameters with the minimum elastic recovery value in titanium alloy milling was also obtained, which can be expanded to the machining measurement of other difficult -to-machine materials. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced silicon carbide matrix composites (Cf/SiC composites) are lightweight, high strength, wear-resistant, and heat-resistant, making them widely used in aerospace and other industries. However, machining holes in Cf/SiC composites is a great challenge due to the anisotropy and high hardness of the material. In this paper, a brazed diamond grinding rod was employed to grind 1 mm diameter holes in Cf/SiC composites, and the influence of grinding parameters on grinding force, hole entrance/exit defects, and hole wall quality was investigated. In addition, the material removal mechanism of Cf/SiC composites and the wear mechanism of the diamond grinding rod were explored. The findings showed that the damage at the hole entrance and exit predominantly manifests as tearing and burring. The damage factor at the hole exit is 3.5% larger than that at the hole entrance, and the damage factor at both the hole entrance and exit reduces with the growth of spindle speed and the decrease of feed rate. In addition, the diameter errors of the hole entrances and exits are all less than 10%, and the entrance diameter is 2.9% larger than the exit. The hole wall defects include fiber fracture, silicon carbide matrix peeling, and inherent porosity, with poorer surface quality at fiber orientation angles (FOA) of 90° to 180°. The main wear mechanisms were identified as abrasive wear and the spalling of abrasive grains. [ABSTRACT FROM AUTHOR]

The effect of milling parameters on chip shape and chip morphology for Zr-based bulk metallic glass was studied in this paper. The milling groove experiments of Zr-based bulk metallic glass (Zr-based BMG) (Zr52Cu17.5Ti16Ni12Nb2.5) were conducted by using a JX-1A ultra-precision machine tool. In order to study the milling quality and milling characteristics of Zr-based bulk metallic glass, it is very important to study the chip shape and chip morphology. In this paper, firstly, the temperature field distribution of Zr-based bulk metallic glass in milling process was simulated by finite element method, and the milling temperature and its distribution at different cutting speeds were obtained. Then the effect of different milling parameters on chip shape and chip morphology was studied, and the reason of the change was analyzed. Then the influence of milling cutters with different geometric parameters on the chip shape and chip morphology of Zr-based bulk metallic glass was also studied. At last, under the same milling conditions, the chip shape and chip morphology of traditional polycrystalline metal materials, monocrystalline metal alloy materials, high-entropy alloy which is in amorphous system, and Zr-based bulk metallic glass were compared. It provides theoretical and experimental basis for the groove milling technology of Zr-based bulk metallic glass. [ABSTRACT FROM AUTHOR]

The milling groove experiments of Zr-based bulk metallic glass (Zr-based BMG) (Zr52Cu17.5Ti16Ni12Nb2.5) are conducted by using an ultra-precision lathe. In order to study the milling groove flank contour accuracy in mesoscale groove milling for Zr-based bulk metallic glass component, the milling force and the flank contour shape were investigated by single-factor experiment. The effect of milling process parameters of Zr-based bulk metallic glass materials on the milling force and the flank contour profile of milling groove were obtained, and the relationship between flank contour profile of milling groove and milling force was also obtained. The flank contour profile of milling groove for Zr-based bulk metallic glass is analyzed theoretically. The effect of milling experimental parameters on the deviation between the actual flank contour profile of milling groove and the theoretical flank contour profile of milling groove is analyzed and summarized through the experiment. [ABSTRACT FROM AUTHOR]