Evaluating Optimal Parameters for Machining Selective Laser Melting Titanium Alloy Using Wire Cut Electrical Discharge Machining

Introduction

Titanium alloys are reputed for their material properties such as high specific strength, biocompatibility and corrosion resistance. Despite their superior properties, their extraction, fabrication and production are expensive due to the requirement of a protective environment, high energy consumption and various other manufacturing associated problems (Boyer, 2010). Titanium alloy, Ti-6Al-4V, having superior mechanical properties, is often referred to as the work horse of titanium alloys and is preferentially used in a variety of applications in the aerospace, chemical, biomedical and automotive industries (Shunmugavel, Polishetty, & Littlefair, 2017). To decrease the overall cost of production and to improve productivity, research on alternative manufacturing methods of titanium alloy has been the primary point of focus (Lutjering & Williams, 2007). In recent years, additive manufacturing (AM) has been widely used for fabricating near-net shape titanium alloy (Ti-6Al-4V) products due to its advantageous features like freedom of design, on-demand manufacturing and high productivity. Titanium alloys are used to manufacture components, where the requirements of design reliability and superior material properties such as high corrosion and thermal resistance, high robustness, high strength to weight ratio and outstanding tendency of alloying, is a priority (Koster, Field, Kahles, Fritz, & Gatto, 1970). The higher melting point of titanium alloy makes it a superior alloy in comparison to other metals. However, some of the material properties of titanium such as low thermal conductivity and high chemical reactivity leads to poor machinability characteristics (Che-Haron, 2001; Polishetty, Shunmugavel, Goldberg, Littlefair, & Singh, 2017). The material used for this project is a SLM titanium alloy, Ti-6Al-4V. SLM is suitable for rapid generation of metal 3D print prototypes. The material properties of SLM titanium alloy, Ti-6Al-4V are given in Table 1.