Reduction in the Volumetric Wear of a Ball Polishing Tool Using Ultrasonic-Vibration-Assisted Polishing Process

Abstract

Ultraprecision freeform polishing using a bonnet or a felt ball mounted on a polishing head plays an important role in the mold and lens production industries. The volumetric wear of a bonnet or a felt polishing ball is still a problem to be solved. The objective of this study was to develop an ultrasonic-vibration-assisted ball polishing process on a CNC machining center to improve the surface roughness of a STAVAX mold steel and to reduce the volumetric wear of the polishing ball. The optimal combination of the ultrasonic-vibration-assisted ball polishing parameters for a plane surface was determined by conducting the Taguchi L18 matrix experiments, ANOVA analysis, and verification experiments. The surface roughness of the polished specimens was improved from the burnished surface roughness of Ra 0.122 μm to Ra 0.022 μm. In applying the optimal plane surface ball burnishing and vibration-assisted spherical polishing parameters sequentially to a fine-milled and burnished aspherical lens surface carrier on a five-axis machining center, the surface roughness of Ra 0.014 μm was obtainable. The improvement in the volumetric wear of the polishing ball was about 62% using the vibration-assisted polishing process compared with the nonvibrated polishing process.

Nanoscale Surface Refinement of CoCrMo Alloy for Artificial Knee Joints via Chemical Mechanical Polishing

“…Consequently, the fabrication of artificial joint prostheses with higher surface smoothness [ 8 ], particularly those composed of CoCrMo alloys, to minimize the generation of particles due to friction wear [ 9 ], is anticipated to significantly improve the lifespan and performance of joint prostheses. Current methods of polishing artificial joints primarily include mechanical polishing [ 10 ], electrolytic polishing [ 11 ], magnetorheological polishing [ 12 , 13 ], and ultrasonic polishing [ 14 , 15 ]. However, mechanical polishing may introduce microscopic scratches, increasing surface roughness.…”

“…and ultrasonic polishing [14,15]. However, mechanical polishing may introduce microscopic scratches, increasing surface roughness.…”

Selected Aspects of Precision Machining on CNC Machine Tools

“…Utilizing ultrasonic-vibrationassisted technology in the finishing operations is a perspective technique for ensuring high geometrical accuracy and machined surface roughness [4]. It was reported that the roughness of the machined surface is significantly improved by ultrasonic-vibration-assisted (UVA) ball polishing from 0.122 µm to 0.022 µm [5,6]. The physical nature of UVA machining's positive effect on machined surface morphology is based on the reduction in frictional force [7].…”