Rotary Ultrasonic Machining of Alumina Ceramic: An Experimental Investigation of Tool Path and Tool Overlapping

Basem M A Abdo,Emad Abouel Nasr,Abdualziz El-Tamimi

doi:10.3390/app10051667

Abstract

Pocket milling has been regarded as one of the most widely used operations in machining. The surface quality of the machined pockets is an essential aspect of any engineering and medical applications. In the current study, rotary ultrasonic machining (RUM) was applied for milling micro-pockets on alumina (Al2O3) ceramic. The objective of this research was to analyze the effect of the tool overlapping parameters on the surface roughness, surface morphology and the profiles of the machined pockets. Subsequently, the effect of different tool path strategies was analyzed on the surface quality and the material removal rate (MRR) of the machined pockets. A scanning electron microscope is used for analyzing the tool wear mechanisms. The experimental results provide evidence that the surface roughness, surface morphology and the MRR have been significantly affected by the considered tool overlapping and the tool path strategies. Furthermore, among the selected tool overlapping parameters (5–25%) and the tool path strategies, the best surface roughness (Ra = 0.155 μm and Rt = 1.432 µm) of the machined pockets can be found at 20% of the tool overlapping with a mix of uni-directional and zigzag tool path strategy.

Highlights

The applications of advanced ceramics such as alumina and zirconia are increasing gradually in the medical and engineering fields due to the significant advancements in the fabrication techniques [1].advanced ceramics offer excellent properties such as high-temperature resistance, high strength to weight ratio and anti-corrosive properties comparing to their competitor materials such as titanium and Inconel alloys
Six pockets have been machined on alumina (Al 2O3) material under various tool overlapping percentages (0%, 5%, 10%, 15%, 20% and 25%)
As mentioned in the previous section, Ra and Rt were measured at six random locations across the feed direction

Summary

Introduction

The applications of advanced ceramics such as alumina and zirconia are increasing gradually in the medical and engineering fields due to the significant advancements in the fabrication techniques [1].advanced ceramics offer excellent properties such as high-temperature resistance, high strength to weight ratio and anti-corrosive properties comparing to their competitor materials such as titanium and Inconel alloys. The applications of advanced ceramics such as alumina and zirconia are increasing gradually in the medical and engineering fields due to the significant advancements in the fabrication techniques [1]. Al2 O3 is classified as difficult to fabricate material due to its poor thermal and electrical conductivities and high hardness [4]. The traditional machining processes such as turning, milling and drilling are not desirable for the economical machining of the Al2 O3 due to excessive tool wear, poor surface integrity and high edge chipping of the machined parts [5]. Non-traditional processes such as chemical machining and electric discharge machining have their own limitation in the machining of ceramic materials as these processes depend on the chemical and electrical properties of the processed

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