Investigations on Wire Electro Discharge Machining (WEDM) characteristics of NiTi Shape Memory Alloy

Abstract

Abstract NiTi(Nickel Titanium) Shape Memory Alloys (SMA) are expeditiously replacing conventional materials in aerospace, automobile, robotics and bio-engineering fields due to its distinctive characteristics like shape memory effect, pseudo elasticity and biocompatibility. Machining of these alloys is strenuous by traditional methods. The unconventional methods like wire electro discharge machining (WEDM) can competently machine these SMAs. But improper selection of WEDM parameters may lead to undesirable results such as poor surface finish and higher machining time. The present study attempts to explore the influence of three system variables; pulse on time, pulse off time and wire feed on performance criteria’s like material removal rate (MRR) and surface roughness (SR) during WEDM of NiTi SMA. Experiments were conducted in accordance with Full Factorial Design (FFD) and results were analysed using Response surface methodology (RSM) based mathematical models. The investigation outcomes revealed that pulse on time has more influence on MRR and SR than pulse off time and wire feed. Maximum MRR is achieved at higher pulse on time with the combination of higher pulse off time and lower wire feed rate. Better surface finish is observed at decreased pulse on time, increased pulse off time and minimum wire feed rate.