EFFECTS OF MACHINING VARIABLES ON SURFACE ROUGHNESS IN WIRE-EDM

Abstract

ABSTRACT Accompanying the development of industry, the demands for alloy materials having high hardness, toughness and impact resistance are increasing. Wire EDM machines are used to cut conductive metals of any hardness or that are difficult or impossible to cut with traditional methods. The machines also specialize in cutting complex contours or fragile geometries that would be difficult to be produced using conventional cutting methods. Machine tool industry has made exponential growth in its manufacturing capabilities in last decade but still machine tools are not utilized at their full potential. This limitation is a result of the failure to run the machine tools at their optimum operating conditions. The problem of arriving at the optimum levels of the operating parameters has attracted the attention of the researchers and practicing engineers for a very long time. The literature survey has revealed that a little research has been conducted to obtain the optimal levels of machining parameters that yield the best machining quality in machining of difficult to machine materials like die steel AISI D3. The die steel AISI D3 is extensively used for hot-work forging, extrusion, manufacturing punching tools, mandrels, mechanical press forging die, plastic mould and die-casting dies, aircraft landing gears, helicopter rotor blades and shafts, etc. The consistent quality of parts being machined in wire electrical discharge machining is difficult because the process parameters cannot be controlled effectively. These are the biggest challenges for the researchers and practicing engineers. Manufacturers try to ascertain control factors to improve the machining quality based on their operational experiences, manuals or failed attempts. Keeping in view the applications of material AISI D3 die steel, it has been selected and has been machined on wire-cut EDM (EZEECUT PLUS WIRECUT EDM) of Electronica Machine Tools Limited. The objective of the present work was to investigate the effects of the various WEDM process parameters on the surface roughness and to obtain the optimal sets of process parameters so that the quality of machined parts can be optimized. The working ranges and levels of the WEDM process parameters are found using one factor at a time approach. The linear regression analysis has been used to investigate the effects of the WEDM process parameters and subsequently to predict sets of optimal parameters for best surface finish.