Science & Technology Development Journal – Engineering and Technology, 3(3):443-451 Open Access Full Text Article Research Article 1 Faculty of Mechanical Engineering, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam 2 Faculty of Transportation Engineering, Ho Chi Minh City University of Technology, Ho Chi Minh City, Vietnam 3 Vietnam National University, Ho Chi Minh City, Vietnam Correspondence Duc Nam Nguyen, Faculty of Mechanical Engineering, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam Email: nguyenducnam@iuh.edu.vn History Received: 10-01-2020 Accepted: 13-10-2020 Published: 22-10-2020 DOI : 10.32508/stdjet.v3i3.658 Copyright © VNU-HCM Press. This is an open- access article distributed under the terms of the Creative Commons Attribution 4.0 International license. Simulation study on polishing of gear surfaces in non-Newtonian fuid Duc Nam Nguyen 1,* , Hung Anh Ly 2,3 , Cong-Truyen Duong 1 Use your smartphone to scan this QR code and download this article ABSTRACT The non-Newtonian fuid is one type of shear thickening fuid which applied to process the com- plicated products. In this study, the new method of shear thickening fuid polishing (STFP) was used to polish the alloy steel SCM435 gears and the principle and performance of polishing pro- cess were also introduced. In the polishing process, the inclination angle of gears was believed to be an important parameter that afects the pressure and sur face quality at diferent position on the tooth surfaces because it determines the contact between the polishing fuid and the tooth surface of the gear. The infuence of the inclination angles on the pressure distribution and char- acteristics of fuid fow was per formed by simulation process. The inclination angles of 0, 4, 8, 12, 16, 20 and 24 degrees were chosen in this study. As a result, the best inclination angle of gears is about 16 degree in the machining process. The tooth surfaces of gear have been in contact with the polishing fuid and the produced pressure reaches of 14.88 kPa. In addition, the infuence of polishing speed on pressure were carried out in this study when inclination angle was established about 16 degree. The produced pressure on tooth surfaces increased with increasing the polishing speed. The results indicated that the diferent polishing speed also greatly afects the sur face qual- ity and machining efciency. Therefore, the suggested machining method can become a suitable processing method for polishing the complicated products. Key words: Non-Newtonian fuid, Gear sur face, Surface roughness, Inclination angle, Pressre, Polishing speed INTRODUCTION e gears have been widely used in the elds of me- chanics, industrial machinery, and engines. It is used for converting the power and speed of the machines. ey can transfer power from small to large, and low to high speeds. e gear transmitters have a lot of advantages, such as a stable gear ratio, quiet opera- tion but not complicated construction, and small size. Usually, the forming or the generating method were used to fabricate the gears. In the forming method, the machining process was carried out with a modu- lar milling tool that matches with the gear module 1 . Besides, the gears can also be machined by hobs, gear shaper tools, and rack-type generating tools in the generating method 27 . For improving the machining performance of ma- chining process, the end-mill was applied to cut the gears using computer numerically controlled (CNC) machine. e cutting tools movement were set up and calculated with Computer Aided-Manufacturing (CAM) program. erefore, the machining period of the gears will be reduced and the productivity will be increased 811 . In order to increase the high load capacity, good strength and high precision transmission of the gears, the gear surfaces are oen tempered and treated to achieve the appropriate hardness 1214 . However, the surface quality of the gears has been reduced aer the heat treatment processing 1517 . erefore, the gear surface aer heat treatment processing will be grinded to improve the surface quality and the time-life of the gear. e cutting process was performed simul- taneously by many abrasive grains with dierent cut- ting edges randomly distributed on the surface of the grinding wheels. As a result, the surface roughness of the gear was achieved about Ra of 1.0 – 0.2 μ m during grinding process 1820 . However, the nished grinding process of gear surfaces will be faced many problems due to the complicated shape of the gear. Consequently, this process requires not only complex machining trajectory but also high machining condi- tions. e result is a large machining time and high cost for the grinding process. In the working process of gears, the corrosion, fa- tigue and wear resistance were depend on the surface roughness of gear. It is an important indicator for evaluating the quality of tooth surfaces of gear. ere- fore, in this study, the shear thickening uid polishing (STFP) method was carried out and used to improve the surface roughness of gear. e suggested method Cite this article : Nguyen D N, Ly H A, Duong C. Simulation study on polishing of gear surfaces in non-Newtonian fuid. Sci. Tech. Dev. J. – Engineering and Technology; 3(3):443-451. 443