High-speed machining of additively manufactured Inconel 718 using hybrid cryogenic cooling methods

ABSTRACT

Although additive manufacturing technologies offer manufacturing highly complex parts, the manufactured parts generally have poor surface quality. Owing to low machinability of hard-to-cut additively manufactured parts, a synergistic approach involving advantages of additive manufacturing and machining processes is needed. This study investigates high-speed machining of additively manufactured nickel alloys using hybrid cryogenic cooling methods. For the first time, a comprehensive study has been presented to compare the synergistic effect of hybrid cooling and lubrication strategies in high-speed milling of additively manufactured parts produced with powder bed fusion and directed energy deposition. The results indicate strong dependency of machinability on additive manufacturing methods and post-treatment strategy used. Hybrid methods make high-speed machining of additively manufactured parts possible, resulting in longer tool life and better surface finish. The cooling plays more significant role on tool life than lubrication. However, it was found that the hybrid cooling methods balanced heat removal and lubrication effects.

KEYWORDS:

• Additive/subtractive hybrid manufacturing
• directed energy deposition
• laser powder bed fusion
• hybrid carbon dioxide
• hybrid liquid nitrogen
• high-speed Inconel 718 machining

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Amin Bagherzadeh

Amin Bagherzadeh is a PhD candidate in the Faculty of Engineering and Natural Sciences at Sabanci University. He is a researcher in Manufacturing Research Laboratory (MRL) and Sabanci University Integrated Manufacturing Technologies Research and Application Center (SU-IMC). His primary research focus is on sustainable manufacturing, tribology and material characterisation. His main interest area is the development of additive/subtractive hybrid manufacturing, high-speed machining and abrasive processes using the new and alternative methods.

Bahattin Koc

Prof Bahattin Koc is a faculty member at Sabanci University where he is the director of the Additive Manufacturing Research Laboratory and the Coordinator (Chair) of Manufacturing Engineering Program. He was the Director of the Sabancı University Integrated Manufacturing Center. Dr. Koc’s research interests include additive manufacturing, heterogeneous object modelling, three dimensional (3D) Bioprinting, computational biomodelling and biofabrication and nano/micro-scale modelling and manufacturing. He has published his research results in more than 100 scientific papers. He holds three patents. Dr. Koc is the recipient of Elginkan Foundation Science and Technology Award, Turkish Heart Association Award, Marie Curie Career Integration Award by EU Research Agency, Most Cited Author in Computer Aided Design Journal Award from Elsevier, University at Buffalo (UB) STOR Inventor Award, UB Reifler Award and UB Interdisciplinary Research and Development Award and more. As PI/Co-PI, Dr. Koc received funding of more than $20 million for his research work. His research work has been supported by major national and international research agencies and organisations such as the Scientific and Technological Research Council of Turkey, the European Union the European Research Council, the Engineering and Physical Sciences Research Council (EPSRC) of UK and the U.S. Army Medical Research.

Erhan Budak

Prof Erhan Budak is a faculty member at Sabanci University where he is the director of the Manufacturing Research Laboratory. He has been involved in machining process and machine tool research for over 3 decades focusing on modelling and measurement methods towards improvement of productivity and quality. Although his main area of expertise in process modelling, machine tool dynamics and cutting stability, in recent years he has been active in surface integrity and alternative cooling methods in cutting and abrasive processes.

Murat Isik

Dr Murat Isik is a research fellow at the Sabanci University Integrated Manufacturing Technologies Research and Application Center. He received his Ph.D. in Materials Engineering from Tohoku University, Japan. He also worked as postdoctoral research fellow for a year in School of Mechanical and Materials Engineering of Washington State University, USA. His previous research interest was in severe plastic deformation, development of biomedical implant materials, tribology, CoCr and Ti alloys. His current topics include additive manufacturing of metallic materials and their characterisation.