An Experimental Investigation for Optimization of Ytterbium Fiber Laser Parameter during Machining of Al/5 Wt%Al2O3-MMC

1. Introduction

Recently Al/Al₂O₃-MMC is gaining increasing industrial acceptance in the aerospace, aircraft, automobile etc industries because of its excellent physical and mechanical properties. But fiber reinforced metal matrix composite machining is one of the major problems which resist its wide spread engineering application as stated by Manna and Bhattacharyya (2003); Cronjager and Meister (1992). Various non-traditional machining processes such as Abrasive Water Jet Machining (AWJM), Electro Chemical Machining (ECM), Electric Discharge Machining (EDM), Wire Electric Discharge Machining (WEDM) etc. have shown their scope of applications towards the machining of fiber reinforced metal matrix composite but these processes have also their own limitations and still remain machining problems like low material removal rate, high surface roughness and poor dimensional accuracy etc. Manufacturing of miniature and micro dimensional part of Al/Al₂O₃-MMC with satisfactory tolerance by any well known machining processes is still very difficult as usually this class of MMC is fabricated by casting process. Hence, a research investigation is needed for searching out a suitable non-conventional machining process for proper machining of Al/Al₂O₃-MMC. In non-traditional machining processes, laser machining has tremendous potential on account of the versatility of its applications and it is expected that it will be successfully and commercially utilized in modern industries. Various studies on laser beam machining (LBM) were carried out by the different researchers to develop various response characteristic models for LBM. Constant gas pressure via an auto tool feed drive control system was introduced to improve the production rate. The better quality of product can be produced by LBM through combinational control of various process parameters.

Early solid state lasers were followed by gas lasing systems; the workhorse of the continuous multi kilowatt range, the carbon dioxide laser was initially operated in 1964 as stated by Martellucci (1993). Although Albert Einstein first published the key principle behind operation of laser in 1917, the first working ruby (Cr⁺³, Al₂0₃) laser was invented by Maiman in 1960 and infra-red laser emission from CO₂ was first reported by Patel in 1964 as stated by Steen (1991). The widely used industrial lasers are argon, YAG and CO₂ laser, and most versatile among them is the CO₂ laser as stated by Chryssolouris and Yablon (1993), and Spalding (1978). The areas of applications of lasers fall in three groups such as optical uses, power uses as in material processing and ultra power uses for atomic fusion as explained by Steen (1991). Bolin (1983) described the applications of Nd:YAG Laser in Laser Materials Processing. The industrial applications involve various materials processing applications as well as micromachining, medical applications, inspection and non-destructive testing, pollution detection, communication and information processing etc. as stated by Harry (1974).