A study ofthe surface microstructure and tool wear of titanium alloys after ultrasonic longitudinal-torsional milling. (May 2020)

• Record Type: Journal Article
• Authors: Chen, Peng; Tong, Jinglin; Zhao, Junshuai; Zhang, Zhiming; Zhao, Bo
• Is Part Of: Journal of manufacturing processes. Volume 53(2020)
• Page Start: 1
• Page End: 11
• Publication Date: 2020-05
• Subjects: Ultrasonic longitudinal-torsional milling -- Titanium alloy -- Micro-texture -- Friction properties -- Tool wear; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2020.01.040
• Languages: English
• ISSNs: 1526-6125

Abstract

Abstract: In order to obtain a better surface micro-morphology on the difficult-to-machine materials such as titanium alloys, the influence of ultrasonic parameters and cutting parameters on the tool path was analyzed theoretically under the ultrasonic longitudinal-torsional vibration. Ultrasonic longitudinal-torsional assisted milling (ULTAM) of titanium alloy was performed, based on a 20° slope. The effects of the ultrasonic parameters and cucuttintting parameters were studied on the surface morphology and surface roughness. The machined surface was examined using scanning electron microscopy (SEM) and white light interferometry. The characterization parameters of the three-dimensional surface micro-morphology including the arithmetic mean height (Sa), the surface skewness (Ssk), and the density of summits (Sds), were obtained under the corresponding cutting parameters. It was found that the ultrasonic amplitude exhibited a significant influence on the surface micro-morphology, followed by the spindle speed n, while the effect of the depth of cut ( ap ), and the feed amount per tooth ( fz ) was relatively less. Under the same cutting parameters for the surface, a comparative analysis for the friction and wear testing was performed between the ultrasonic milling and conventional milling (CM). The results showed that the ULTAM transformed the original ravines and anisotropic surface imperfections into an uniform and orderly scaly micro-texture, thus forming an isotropic surface texture in all directions. Furthermore, ULTAM transformed the surface into a fish-scale micro-texture, and thereby improved the surface quality. The fine and smooth surface morphology was conducive by shortening the running-in time, allowing the stable state of friction to be reached quickly, and thereby offering a higher stability in the friction process. `Compared to CM, the tool wear was reduced by 30%, due to the unique tool-work separation characteristics of the ultrasonic longitudinal-torsional assisted milling. Moreover, the unique intermittent cutting characteristics of the ultrasonic longitudinal and torsional milling not only reduced the cutting force and tool wear, but also inhibited the generation of the burr, thus improving the surface quality.