Machining a glass rod with a lathe-type electro-chemical discharge machine

Abstract

This paper deals with the performance of electro-chemical discharge machining (ECDM) of a revolving glass rod. ECDM has been studied for machining insulating materials such as glass and ceramics. In conventional ECDM, an insulating workpiece is dipped in an electrolyte as a working fluid and a tool electrode is pressed on the surface with a small load. In the experiments, a workpiece was revolved to provide fresh working fluid into a gap between the tool electrode and the workpiece. A soda lime grass rod was machined with a thin tungsten rod in NaCl solution. The applied voltage was changed up to 40 V. The rotation speed was set to 0, 0.3, 3 and 30 min −1 . Discharge was observed over an applied voltage of 30 V. The width and depth of the machined grooves and the surface roughness of their bottom were increased with increase of the applied voltage. Although the depth of machining at 3 min −1 was the same as that at 30 min −1 , the width and roughness at 30 min −1 were smaller than those at 3 min −1 . Moreover, because the thickness of vaporization around the tool electrode was decreased with increase of the rotation speed, the width of the machined groove became smaller.

Removal Mechanism of Glass Using Lathe-Type Electrochemical Discharge Machine

“…With an increase of the rotation speed of the workpiece, the removal rate was increased in the previous paper 11) . The mechanism above explains this trend, that is, the removal of the generated sodium silicate was accelerated by the increased flow of the electrolyte.…”

“…Because the viscosity of the electrolyte is much smaller than that of sodium silicate and the surface area of the tool electrode is small, the fluid resistance (F5) does not affect very much and its variation is also small. The surface roughness sometimes reaches several tens of micrometers 11) . On the other hand, the coefficient of the linear thermal expansion and thermal conductivity of silica glass are 10 7 /K and 3 W/(m•K), respectively 19) .…”

“…In ECDM, cracks are induced by thermal expansion due to the discharge heat accumulated in a workpiece. For a solution, the authors have proposed a forced discharge dispersion method with several tool electrodes 10) and a lathe-type ECDM machine in which discharge points are shifted and cooled with flesh electrolyte 11) . In groove machining, though periodic waviness, similar to chattering mark in cutting was observed at a low rotation speed, it became smaller with an increase of the speed.…”

Parametric Analysis of Electrochemical Discharge Drilling on Soda-Lime Glass Material Using Taguchi L27 Orthogonal Array Method

“…As a result, the surface will be scraped off with the electrode tip. The etching rate rises noticeably with the temperature and the concentration of hydroxyl anion [6,[14][15][16].…”

Experimental Study of the Tool Wear During the Electrochemical Discharge Machining

“…Among the different applications of the ECDM, drilling has been the most frequent application of this process [2]. In addition, the ECDM has been used as the lathe for machining of a cylindrical glass rod [8]. It has also been used for slicing ceramics and glass with a wire as the cathode electrode.…”