Abstract

In this study, micro-grinding was performed to investigate the machining characteristics of alumina and zirconia. The machining of ceramics remains highly challenging owing to their properties, such as high brittleness and wear resistance, which leads to a shorter tool life and high machining costs. Polycrystalline diamond (PCD) was selected as the tool material, as it is suitable for machining hard and brittle materials, and micro-electrical discharge machining (EDM) was used to fabricate PCD micro-tools. When using a resistor-capacitor generator circuit in micro-EDM, the discharging energy is related to the working capacitance, and by controlling the working capacitance, the different edge radii and the surface roughness of the tool can be easily achieved. The feed rate, depth of cut, and rotation speed were set as experimental parameters to investigate the grinding characteristics of the ceramics. During the experiment, the grinding force and roughness of the bottom surface were monitored, and the roughness of the machined surfaces was measured using a three-dimensional surface profiler. A working capacitance of 1000 pF was used to fabricate a tool with an edge radius of 3.5 µm. The lower radius of the tool edge resulted in a decrease of the cutting force by 50% at most and a surface roughness of 19 nm Ra.

Highlights

  • Ceramic materials have attracted attention as possible substitutes for metals for structural parts used in several industrial fields and multiple advanced industries due to promising characteristics, such as low density and high strength, as well chemical resistance [1,2,3,4,5].the advantageous mechanical properties of ceramics can be a disadvantage in fine-shape processing [6,7]

  • Micro-tools made of cemented carbide suffer from severe tool wear while processing ceramic materials

  • When a Polycrystalline diamond (PCD) tool is machined by electrical discharge machining (EDM), the surface of the tool is covered with m

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Summary

Introduction

Ceramic materials have attracted attention as possible substitutes for metals for structural parts used in several industrial fields and multiple advanced industries due to promising characteristics, such as low density and high strength, as well chemical resistance [1,2,3,4,5].the advantageous mechanical properties of ceramics can be a disadvantage in fine-shape processing [6,7]. Owing to the high hardness of ceramic materials, the tool wear increases during mechanical processing, which increases the cost of processing; because of the brittle nature of these materials, the machined surface is not smooth or breaks irregularly. These issues limit the application of ceramics, in fields that use structures of tens to hundreds of microns. In the grinding of oxidized zirconium ceramics using a diamond-coated tool, Kisaki et al achieved a reduction of the fracture toughness of the material and the machining force and changed the surface condition during processing with laser [9]

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