FACULTY OF INDUSTRIAL ENGINEERING Department of Industrial Engineering Doctor of Philosophy SURFACE FINISH OPTIMIZATION IN FACE MILLING GRADE 5 TITANIUM ALLOY FOR SUSTAINABLE MANUFACTURING By Imran Masood Sustainability achievement of difficult-to-machine materials is major concern now-a-days. In this work the machining sustainability of Ti-6Al-4V hardened up to 55 HRC is assessed through a novel technique of iso-response method, in which the response value i.e. surface finish is taken as criteria for evaluation and comparison among dry, conventional and cryogenic machining. Experiments were designed in DOE for central composite design and performed face milling of Titanium alloy Ti-6Al-4V using PVD coated carbide inserts under three conditions of cooling and measured the response values. Feed, speed and depth of cut were used as input parameters. The parameters giving nearly same response values in each scenario were used to evaluate the sustainability of each mode for cutting power, machining time, material removal rate, tool life and machining cost. Comparing the average results achieved by cryogenically cooled experiments, it is found that 61.9% less cutting power, 15.12% less machining time , 47.55 % less electricity cost and 47.59% less machine operating cost observed for cryogenically cooled experiments as compared with dry machining. Coolant cost is found 13.33 times cheaper for cryogenic as compared with conventional machining. Whereas increased material removal rate of 81.12% and increased cutting tool life by 5.2 times for cryogenic machining as compared to dry one. Furthermore on comparison of cryogenic machining with conventional machining, it is found that cutting time is saved by 3 %, cutting tool life is increase by 1.34 times, electricity cost is saved by 39 % and labour cost is saved by about 38%. iv The results indicate that cryogenic cooling is more sustainable as compared to dry and conventional cooling process. It was found that the cryogenic machining gives the best results for tool life, surface finish of machined part, productivity with least impact on the environment, least energy cost and machining cost. Findings of this research are helpful in assessing sustainability for machining industry to reduce tooling cost, machining cost, worker’s health problems, environmental impact and will help to select sustainable input parameters. The proposed model gives the machining industry a unique direction to adopt the sustainable input parameters.