Experimental Investigation of Tool Vibration Effect on the Surface Roughness in Facing Operation of PMMA Material

Abstract

Poly Methyl Methacrylate (PMMA) is one of the few plastics used in optical applications. The Diamond Turning machine is used for cutting PMMA for optical applications, as finish cut and rough cut are performed using the CNC lathe machine. The optical applications require the best surface finish for the maximum transmission of light and to avoid light scattering. The best surface finish can be achieved by machining PMMA at optimized parameters. The optimum cutting parameters may not give good results due to the presence of vibration in the process. In this paper, the effect of vibration on cutting parameters is experimentally studied. The experimentation has been carried out to determine the relation between the tool vibration acceleration amplitude and the surface finish. The facing operation is performed on the PMMA material. The operation is performed using the CNC lathe machine. The three level full factorial design approach is used for the experimentation. The feed rate, cutting speed and the depth of cut are selected as influencing parameters by keeping all the other parameters constant. The Tungsten carbide cutting tool is used for the cutting operation. The accelerometer is used to gather vibration data by using the NI LABVIEW software. The analysis of the obtained results is done by using ANOVA. It is seen in the graphs that vibrations in Z- direction mainly affect the surface finish. The maximum value of the surface finish is 0.243µm, when acceleration is 2.93 m/s2, and the minimum value of surface finish 0.05µm, when acceleration is 2.03 m/s2. The optimum parameter values to obtain the minimum vibrations and the best surface finish are 274.89 m/min cutting speed, 0.05 mm/rev and 0.1 mm depth of cut.
Copyright © 2017 Praise Worthy Prize - All rights reserved.