Powder Mixed Electrical Discharge Machining of Titanium Alloy (Ti-6A1-4V)

摘要

Being a "difficult-to-machine" aerospace material, titanium alloy suffers poor machinability for most cutting processes. But, there are strong needs for productive machining. The current means of machining these materials is dominated by mechanical cutting methods, which are costly due to high tooling costs,poor surface quality and limitations in the workpiece features. Although electrical discharge machining (EDM) is suitable for machining titanium alloys,selection of machining parameters for higher machining rate and accuracy is a challenging task. The powder mixed electrical discharge machining (EDM) technology may be able to circumvent problems encountered in mechanical machining methods. In this paper, the experiment of powder mixed electrical discharge machining of titanium alloy (Ti-6A1-4V) were did. Experiments based on the appropriate orthogonal array are conducted first. In addition, three independent parameters such as peak current,pulse-on time,and duty ratio were adopted for evaluation by the Taguchi method. Using the multiple regression analysis, the fitting formulas of the material removal rate (MRR) and the tool wear rate (TWR) were acquired. Scanning electron microscopy (SEM),energy dispersive spectrograph (EDS) and surface roughness measurement were performed to study the surface characteristics of the machined samples. Experimental results indicate that the powder mixed electrical discharge machining technology effectively improves the surface roughness. It is seen that machining performances are affected mostly by the peak current and pulse-on time during micro-electrodischarge machining of titanium alloy. Mathematical models have been developed to establish the relationship between various significant process parameters.