Sustainability and machinability evaluation of drilling WAAM-CMT and Wrought Ti-6Al-4V: Comparison of three drilling tools

Various researchers acknowledged Wire Arc Additive Manufacturing- Cold Metal Transfer (WAAM-CMT) as a specialised additive manufacturing methodology for difficult-to-machine materials that is progressively offering an economical advantage to traditional forging and casting methods. After manufacturing alloy namely Ti-6Al-4V using WAAM-CMT; machining operation like drilling plays a vital role in achieving the desired dimensions/shape and surface finish of the required product in specific applications. This novel work compares the tool performance of three different cutting tools used for drilling Ti-6Al-4V alloy produced by forging and WAAM-CMT by assessing sustainability and machinability aspects. The drill bits performed better for the wrought Ti-6Al-4V as compared to WAAM-CMT Ti-6Al-4V, which was due to the superior mechanical characteristics of the WAAM-CMT component. The fabrication cost via the WAAM-CMT process was approximately 192.8 % more than the fabrication via the wrought process. The overall machine costs for drilling wrought Ti-6Al-4V decreased by about 35.44 %, 19.85 %, and 26.74 % for Tool A, Tool B, and Tool C, respectively, as compared to drilling WAAM-CMT Ti-6Al-4V. The use of WAAM-CMT for the manufacturing of the Ti-6AL-4V plate increased Carbon Emission (CE) by roughly 2.8%. The total CE from both additive and subtractive stages of WAAM-CMT Ti-6AL-4V increased by about 45.41% and 2.3% for Tool A and Tool B, respectively, whereas the CE decreased by 3.1% for Tool C as compared to wrought Ti-6Al-4V. The novel sustainability and machinability findings are critically discussed for industry practitioners and academia.