Photochemical Machining: A Less Explored Non-Conventional Machining Process

Introduction

The stringent dimensional requirements with high surface finish and complex shapes are cannot be accomplished by the conventional machining processes. The hard materials are also constraints for the conventional machining methods. Furthermore, the augment in temperature and residual stresses generated in the work piece because of the conventional machining processes may possibly not be tolerable for various applications. Therefore, Now a day's, non-conventional machining processes are frequently used for the manufacturing of a wide variety of parts. The non-conventional machining processes include Electrical Discharge Machining (EDM), Laser machining, Electrochemical Machining (ECM), Abrasive jet machining, Photochemical Machining (PCM), etc. The comparatively less studied non-conventional machining process is Photochemical etching (Figure 1) (Gamage and DeSiva, 2015). The PCM process is based on the amalgamation of photoresist imaging and chemical etching (Allen, 2004). Photochemical machining process is a precision contouring of metal into any shape, size or form without using of physical force, by a controlled chemical reaction. Material is etched by microscopic electrochemical cell action, as occurs in chemical dissolution or corrosion of a metal.

Figure 1.

PCM - Less explored Non conventional machining process (Gamage and DeSiva, 2015)

In photochemical machining, the difficult thin 2D flat metal components are produced which are free from stress and burr with low cost and less delivery time apart from other advantages. As this process is sovereign of intricacy of the machining, this process becomes an efficient, fast, cost competitive technique of producing components of metal with intricate designs unrivaled by any another conventional metal forming process. An additional benefit of the process is the possibility for etching a broad range of materials i.e. metals, alloys, glasses, ceramics, etc. However, the metals and alloys like copper, magnesium, zinc, aluminium, steels, nickel, monel, kovar, etc. are easily etched using PCM. Because of the assortment of materials used in the PCM process, the PCM is playing a dominant role in the precision parts manufacturing in different areas such as automotive, electronics, aerospace, optics, medical, jewelry, etc. Typical applications are the productions of integrated circuit lead frames, television shadow masks, mobile telephone gaskets, decoration on watch parts, suspension head assemblies, and jewellery (Yadev and Teli, 2014).

This chapter presents the parametric effect issues of the less explored photochemical machining process. The background focusing on the brief history and the selective literature review is discussed after this section. Further, the PCM process details along with the parameters for experimentation are presented in the succeeding section. Then, the influence of the process parameters on performance measures of the PCM is discussed. The surface topography of the photochemically machined sample specimens is also conferred using scanning electron microscopy (SEM) to reveal the process parameters influence. The scope for future work in this perspective for PCM is briefed following the summary of the chapter.