Micro-hole geometry evolution on glass by abrasive air-jet micromachining


Micro structure manufacturing is needed more in industries than ever before. For this purpose, several micromachining techniques are developed to fabricate 2D and 3D micro structures. Abrasive air-jet (AAJ) micromachining technique has become an attractive technology for the fabrication of microstructures on a wide range of engineering materials due to energy-efficient and unique method for micromachining components made from advanced but difficult-to-machine materials, including glass, ceramics, quartz and silicon which are increasingly selected for constructing modern micro-featured devices.

Huaizhong Li at Griffith University in collaboration with Jun Wang, Ngaiming Kwok, and Guan Heng Yeoh at UNSW Australia and also Thai Nguyen at The University of Sydney in Australia have conducted a research to characterize the abrasive air-jet micromachining process for the features formed on the target material and that depends on various parameters, such as nozzle shape and size, particle size, air pressure and flow rate. Their research work which presents a thorough study on the evolution of micro and blind holes on glass during abrasive air-jet machining is now published in Journal of Manufacturing Processes.

The research team conducted their studies under different practical settings of air pressure, particle mass flow rate and drilling time. A 3D laser measurement microscope was used to characterize the machined hole profiles. Three types of hole surface contours, convex, flat, and concave were used.

The authors shows that under different cutting parameters, the hole shapes exhibit some variations in terms of the bottom surface and the side kerf slope. Within the operating range used, three main types of hole bottom contours were obtained. In addition, the kerf slope varied from steep to gradual. They also found that the evolution of the micro hole contours is caused by the variation of the AJM parameters.

Moreover, at a low flow rate, the hole bottom was formed with a convex shape, which might be attributed to the fact that the distribution of particles at the nozzle center was less than that around the brim. As the particle flow rate increased, the bottom surface evolved from convex to flat or even concave. Furthermore the researchers found that the occurrence of different contour types is strongly affected by the magnitudes of air-jet pressure and particle flow rate. If proper selection of air-jet pressure and the particle flow rate, a desired feature can be fabricated. The study by Huaizhong Li and colleagues will help advance fabricating micro hole using abrasive air-jet micromachining.

micro-hole geometry evolution on glass by abrasive air-jet micromachining-Advances in Engineering
Figure legend: Three typical types of hole bottom contours fabricated on glass by AJM: (a) convex, (b) flat, and (c) concave


About the author

Dr Huaizhong Li is currently a Senior Lecturer in Mechanical Engineering at the School of Engineering and Built Environment, Griffith University, Australia. He received a bachelor of engineering degree from Tsinghua University in 1988, a master of engineering degree from Xi’an Jiaotong University in 1991, and a PhD from the National University of Singapore (NUS) in 2002. He has extensive R&D experience in academia and industry. He worked as a Senior Research Engineer at Singapore Institute of Manufacturing Technology (SIMTech) from 2001 to 2008, and as an Associate Principal Engineer with Vestas Technology R&D Singapore from 2008 to 2010. Before moved to Griffith University, he was a Lecturer at the School of Mechanical and Manufacturing Engineering, The University of New South Wales (UNSW), Australia, from 2011 to 2014. His current research interests include advanced manufacturing technologies, machine dynamics, vibration control, and mechatronics. He has had over 90 publications including referred technical articles in international journals, conference proceedings, and scholarly book chapters, and filed 2 patents. He has supervised a number of PhD and master by research students to completion. Since 2011, he has been granted over AUD1.043M research funding. He has received a number of honours and recognitions, including the 2015 Thatcher Bros Prize by the Institution of Mechanical Engineers (IMechE).

About the author

Jun Wang is a Professor in Manufacturing Engineering at The University of New South Wales (UNSW), Australia. He received a bachelor degree from Dalian University of Technology in 1982 and a PhD from the University of Melbourne in 1993. He worked at the University of Melbourne as a Research Fellow before moving to Queensland University of Technology in 1995 and then to UNSW in 2005. He initiated and developed the research in abrasive jet processing at UNSW. His current research interests include multi-length scale machining and fabrication using impacting particles and high energy beams, advanced and micro-cutting tools, cutting tool materials, engineering tribology and 3D printing.

He has had over 470 publications, including more than 320 refereed journal articles, a monograph and 25 edited books. He has served as the Chairman of the International Committee for Abrasive Technology (2011-2015), the founding Editor-in-Chief of the International Journal of Abrasive Technology, and the President of the Ausinan Science and Technology Society (2013-2015).

He also serves on a number of positions for government, academic and professional organisations in Australia, China, Japan, USA and Malaysia, notably the Expert Consulting Committee for the OCAO of the State Council of China. Jun Wang is associated with five international journals as an editor and is a member of the editorial board for further 9 journals. He has received a number of honours and recognitions, including an Endeavour Executive Award from the Australian Federal Government, Advanced Innovation Award from NewSouth Innovations in Australia, recipient of the Outstanding Young Scholar Foundation from the National Natural Science Foundation of China, and the 2015 Thatcher Bros Prize from the Institution of Mechanical Engineers (IMechE). Jun Wang is a Fellow of the Institution of Engineers Australia and a Fellow of the International Society of Nano-manufacturing.

About the author

Dr Ngai Ming Kwok received the PhD degree from University of Technology Sydney, Australia, in 2007; the MPhil degree from Hong Kong Polytechnic University, China, in 1997; and the BSc degree from University of East Asia, China, in 1993. He is now a Lecturer of Mechatronics Engineering at the School of Mechanical and Manufacturing Engineering, The University of New South Wales, Australia, since 2008.

His research interest includes image processing, intelligent computation, and automatic control. He is a postgraduate student supervisor. Dr Kwok received the best paper award at the CASE 2007 conference, and the best paper award finalist at the ICIT 2005, CASE 2006, and ICMLC 2013 conferences. He had been the technical programme committee member of the CISP-BMEI conference, 2012−2017.

About the author

Thai Nguyen received PhD from The University of Sydney in 2005. His initial employment started on a shop floor as a mechanic for four years, prior to his study at University of Technology, Sydney, where he received his first BE degree in Mechanical Engineering with First Class Honours in 1999. His employment history includes six years of practical experience as a Design/Product and Process Engineer for Australian global-scaled manufacturers and ten years as a Researcher and a Lecturer in The University of Sydney and The University of New South Wales. Dr Nguyen has won two competitive Discovery Research grants from the Australian Research Council as a Chief Investigator. He has received a number of research awards and honours, including a coveted Australian Postdoctoral Fellowship (ARC APD) and a Silverstar Research Award from The University of New South Wales.

His research interests are to explore the complex interactions of fluid mechanics, thermal cycling and mechanical deformation in the surface integrity and microstructure of machined components. The applications have been found in many advanced precision machining processes such as grinding-hardening, abrasive jet micro-machining, field assisted machining/polishing and machining of difficult-to-machine materials. He has registered a patent and published more than 50 articles, many of which have been disseminated in the most prestigious journals in Physics and Mechanical Engineering, including 18 articles ranked as top “A*” (12) and “A” (6), according to the Excellence in Research for Australia, ERA 2010.

About the author

Dr Guan Heng Yeoh is a Professor of Mechanical and Manufacturing Engineering at University of New South Wales and a Principal Research Scientist at Australia Nuclear Science Technology Organisation. He obtained his PhD degree in Mechanical Engineering from the University of New South Wales. He has authored 8 books, 11 book chapters and over 250 publications. He has also obtained the Brennan Medal for best book publication, Institute of Chemical Engineers, UK, 2009; ANSTO Award: recognition for excellence in literature publication, 2009; and NASA Award: novel and innovative research work in solidification for the manufacturing of electr onic components in microgravity environment, 1992.


Huaizhong Li, Jun Wang, Ngaiming Kwok, Thai Nguyen, and Guan Heng Yeoh. A study of the micro-hole geometry evolution on glass by abrasive air-jet micromachining. Journal of Manufacturing Processes, Volume 31 (2018), Pages 156-161.


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