Study of Micro-groove Generation on Titanium Alloy (Ti6Al4V) using Novel WEDM and WECM Sequential Electro Micro Machining (SEMM) Technique

Abstract

Abstract The micro-part manufacturing can be accomplished by the execution of different micro-machining techniques. The sequential machining is one of the most promising techniques which dictate the structured approach towards the fabrication of highly precise micro-features in sophisticated components. The newly coined Sequential Electro Micro Machining (SEMM) technique has been implemented for the improvement of overall machining efficiency and enhancement in surface characteristics of the part during machining. In the chain of sequential machining, the present research paper has introduced a novel sequential combination of micro Wire Electro Discharge Machining (µWEDM) and micro Wire Electro-Chemical Machining (µWECM) processes. The µWEDM process was carried out on the standard wire cut EDM machine, whereas µWECM was performed on indigenously designed and developed system setup. The micro-grooves on difficult to cut material such as titanium alloy (Ti6Al4V) was initially generated by applying µWEDM process. The µWEDM is a thermal process, where the shaping of micro-groove was accomplished rapidly due to the existence of high-intensity spark discharges. The spark produced also generates recast layer comprising of cracks, micro-pores and numerous micro-craters in the heat affected zone of the machined region. During experimentation, the micro-groove using µWEDM process was cut at different machining voltages. In order to make out the best sequential machining combination, the machining voltage at which the least surface defects occurred on micro-groove was selected for sequencing with the subsequent process. In present experimentation, the least width overcut of the groove was obtained at 10V. The µWECM process was then applied to ameliorate the surface defects and other irregularities imparted to micro-groove during the µWEDM process. The effects of machining process parameters in µWECM, such as applied voltage, machining time and duty ratio on µWEDMed part was investigated. The sequential machining experiments were then conducted by choosing the best input process parameters in both the processes. The experimental results thus obtained after the application of diversified sequential micro-machining processes revealed an improved machining efficiency and high surface quality of micro-groove. Thus the µWEDM process for shaping the groove and µWECM process for finishing the groove was conducted successfully