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Frontiers of Mechanical Engineering

, Volume 12, Issue 1, pp 18–32 | Cite as

Recent advances in micro- and nano-machining technologies

  • Shang Gao
  • Han Huang
Open Access
Review Article

Abstract

Device miniaturization is an emerging advanced technology in the 21st century. The miniaturization of devices in different fields requires production of micro- and nano-scale components. The features of these components range from the sub-micron to a few hundred microns with high tolerance to many engineering materials. These fields mainly include optics, electronics, medicine, bio-technology, communications, and avionics. This paper reviewed the recent advances in micro- and nano-machining technologies, including micro-cutting, micro-electrical-discharge machining, laser micro-machining, and focused ion beam machining. The four machining technologies were also compared in terms of machining efficiency, workpiece materials being machined, minimum feature size, maximum aspect ratio, and surface finish.

Keywords

micro machining cutting electro discharge machining (EDM) laser machining focused ion beam (FIB) 

Notes

Acknowledgements

SG was sponsored by the Chinese Scholarship Council (CSC) under postdoctoral fellow program. HH would like to acknowledge the financial sponsorship from Australia Research Council (ARC) under Future Fellowship program.

References

  1. 1.
    Luo X, Cheng K, Webb D, et al. Design of ultraprecision machine tools with applications to manufacture of miniature and micro components. Journal of Materials Processing Technology, 2005, 167(2–3): 515–528CrossRefGoogle Scholar
  2. 2.
    Qin Y. Micromanufacturing Engineering and Technology. Oxford: William Andrew, 2010Google Scholar
  3. 3.
    Alting L, Kimura F, Hansen H N, et al. Micro engineering. CIRP Annals—Manufacturing Technology, 2003, 52(2): 635–657CrossRefGoogle Scholar
  4. 4.
    Crichton M L, Archer-Jones C, Meliga S, et al. Characterising the material properties at the interface between skin and a skin vaccination microprojection device. Acta Biomaterialia, 2016, 36: 186–194CrossRefGoogle Scholar
  5. 5.
    Vaezi M, Seitz H, Yang S. A review on 3D micro-additive manufacturing technologies. International Journal of Advanced Manufacturing Technology, 2013, 67(5–8): 1721–1754CrossRefGoogle Scholar
  6. 6.
    Liu X, Devor R E, Kapoor S G, et al. The mechanics of machining at the microscale: Assessment of the current state of the science. Journal of Manufacturing Science and Engineering, 2004, 126(4): 666–678CrossRefGoogle Scholar
  7. 7.
    Spearing S M. Materials issues in microelectromechanical systems (MEMS). Acta Materialia, 2000, 48(1): 179–196CrossRefGoogle Scholar
  8. 8.
    Rajurkar K P, Levy G, Malshe A, et al. Micro and nano machining by electro-physical and chemical processes. CIRP Annals—Manufacturing Technology, 2006, 55(2): 643–666CrossRefGoogle Scholar
  9. 9.
    Liu K, Lauwers B, Reynaerts D. Process capabilities of micro-EDM and its applications. International Journal of Advanced Manufacturing Technology, 2010, 47(1–4): 11–19CrossRefGoogle Scholar
  10. 10.
    Masuzawa T. State of the art of micromachining. CIRP Annals— Manufacturing Technology, 2000, 49(2): 473–488CrossRefGoogle Scholar
  11. 11.
    Madou M J. Manufacturing Techniques for Microfabrication and Nanotechnology. Boca Raton: CRC Press, 2011Google Scholar
  12. 12.
    Brinksmeier E, Riemer O, Stern R. Machining of precision parts and microstructures. In: Inasaki I, ed. Initiatives of Precision Engineering at the Beginning of a Millennium. Berlin: Springer, 2002, 3–11CrossRefGoogle Scholar
  13. 13.
    Brousseau E B, Dimov S S, Pham D T. Some recent advances in multi-material micro-and nano-manufacturing. International Journal of Advanced Manufacturing Technology, 2010, 47(1–4): 161–180CrossRefGoogle Scholar
  14. 14.
    Qin Y, Brockett A, Ma Y, et al. Micro-manufacturing: Research, technology outcomes and development issues. International Journal of Advanced Manufacturing Technology, 2010, 47(9–12): 821–837CrossRefGoogle Scholar
  15. 15.
    Dimov S S, Matthews C W, Glanfield A, et al. A roadmapping study in multi-material micro manufacture. In: Proceedings of the Second International Conference on Multi-Material Micro Manufacture. Oxford: Elsevier, 2006, xi–xxvGoogle Scholar
  16. 16.
    Chae J, Park S S, Freiheit T. Investigation of micro-cutting operations. International Journal of Machine Tools & Manufacture, 2006, 46(3–4): 313–332CrossRefGoogle Scholar
  17. 17.
    Sumitomo T, Huang H, Zhou L, et al. Nanogrinding of multilayered thin film amorphous Si solar panels. International Journal of Machine Tools & Manufacture, 2011, 51(10–11): 797–805CrossRefGoogle Scholar
  18. 18.
    Yin L, Huang H. Brittle materials in nano-abrasive fabrication of optical mirror-surfaces. Precision Engineering, 2008, 32(4): 336–341CrossRefGoogle Scholar
  19. 19.
    Huo D. Micro-Cutting: Fundamentals and Applications. London: John Wiley & Sons, 2013Google Scholar
  20. 20.
    Lu Z, Yoneyama T. Micro cutting in the micro lathe turning system. International Journal of Machine Tools & Manufacture, 1999, 39(7): 1171–1183CrossRefGoogle Scholar
  21. 21.
    Rahman M, Asad A, Masaki T, et al. A multiprocess machine tool for compound micromachining. International Journal of Machine Tools & Manufacture, 2010, 50(4): 344–356CrossRefGoogle Scholar
  22. 22.
    Weule H, Hüntrup V, Tritschler H. Micro-cutting of steel to meet new requirements in miniaturization. CIRP Annals—Manufacturing Technology, 2001, 50(1): 61–64CrossRefGoogle Scholar
  23. 23.
    Câmara M A, Rubio J C, Abrão A M, et al. State of the art on micromilling of materials, a review. Journal of Materials Science and Technology, 2012, 28(8): 673–685CrossRefGoogle Scholar
  24. 24.
    Egashira K, Mizutani K. Micro-drilling of monocrystalline silicon using a cutting tool. Precision Engineering, 2002, 26(3): 263–268CrossRefGoogle Scholar
  25. 25.
    Dornfeld D, Min S, Takeuchi Y. Recent advances in mechanical micromachining. CIRP Annals—Manufacturing Technology, 2006, 55(2): 745–768CrossRefGoogle Scholar
  26. 26.
    Aurich J C, Engmann J, Schueler G M, et al. Micro grinding tool for manufacture of complex structures in brittle materials. CIRP Annals—Manufacturing Technology, 2009, 58(1): 311–314CrossRefGoogle Scholar
  27. 27.
    Hoffmeister H, Wenda A. Novel grinding tools for machining precision micro parts of hard and brittle materials. In: Proceedings of the 15th Annual Meeting of the ASPE. 2000, 152–155Google Scholar
  28. 28.
    Park H, Onikura H, Ohnishi O, et al. Development of microdiamond tools through electroless composite plating and investigation into micro-machining characteristics. Precision Engineering, 2010, 34(3): 376–386CrossRefGoogle Scholar
  29. 29.
    Chen W K, Kuriyagawa T, Huang H, et al. Machining of micro aspherical mould inserts. Precision Engineering, 2005, 29(3): 315–323CrossRefGoogle Scholar
  30. 30.
    Luo X, Cheng K, Webb D, et al. Design of ultraprecision machine tools with applications to manufacture of miniature and micro components. Journal of Materials Processing Technology, 2005, 167(2–3): 515–528CrossRefGoogle Scholar
  31. 31.
    Kim J, Kim D S. Theoretical analysis of micro-cutting characteristics in ultra-precision machining. Journal of Materials Processing Technology, 1995, 49(3–4): 387–398CrossRefGoogle Scholar
  32. 32.
    Shaw M C. Precision finishing. CIRP Annals—Manufacturing Technology, 1995, 44(1): 343–348CrossRefGoogle Scholar
  33. 33.
    Liu X, Jun M B, Devor R E, et al. Cutting mechanisms and their influence on dynamic forces, vibrations and stability in microendmilling. In: Proceeding of the ASME 2004 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2004, 583–592Google Scholar
  34. 34.
    Bissacco G, Hansen H N, De Chiffre L. Size effects on surface generation in micro milling of hardened tool steel. CIRP Annals— Manufacturing Technology, 2006, 55(1): 593–596CrossRefGoogle Scholar
  35. 35.
    Kim C, Mayor J R, Ni J. A static model of chip formation in microscale milling. Journal of Manufacturing Science and Engineering, 2004, 126(4): 710–718CrossRefGoogle Scholar
  36. 36.
    Weule H, Hüntrup V, Tritschler H. Micro-cutting of steel to meet new requirements in miniaturization. CIRP Annals—Manufacturing Technology, 2001, 50(1): 61–64CrossRefGoogle Scholar
  37. 37.
    Liu X, Devor R E, Kapoor S G. An analytical model for the prediction of minimum chip thickness in micromachining. Journal of Manufacturing Science and Engineering, 2006, 128(2): 474–481CrossRefGoogle Scholar
  38. 38.
    Vogler MP, Devor R E, Kapoor S G. On the modeling and analysis of machining performance in micro-endmilling, Part I: Surface generation. Journal of Manufacturing Science and Engineering, 2004, 126(4): 685–694CrossRefGoogle Scholar
  39. 39.
    Vogler MP, Kapoor S G, Devor R E. On the modeling and analysis of machining performance in micro-endmilling, Part II: Cutting force prediction. Journal of Manufacturing Science and Engineering, 2004, 126(4): 695–705CrossRefGoogle Scholar
  40. 40.
    Son S M, Lim H S, Ahn J H. Effects of the friction coefficient on the minimum cutting thickness in micro cutting. International Journal of Machine Tools & Manufacture, 2005, 45(4–5): 529–535CrossRefGoogle Scholar
  41. 41.
    Dow T A, Miller E L, Garrard K. Tool force and deflection compensation for small milling tools. Precision Engineering, 2004, 28(1): 31–45CrossRefGoogle Scholar
  42. 42.
    Bao WY, Tansel I N. Modeling micro-end-milling operations. Part I: Analytical cutting force model. International Journal of Machine Tools & Manufacture, 2000, 40(15): 2155–2173Google Scholar
  43. 43.
    Bao WY, Tansel I N. Modeling micro-end-milling operations. Part II: Tool run-out. International Journal of Machine Tools & Manufacture, 2000, 40(15): 2175–2192Google Scholar
  44. 44.
    Duan X, Peng F, Yan R, et al. Estimation of cutter deflection based on study of cutting force and static flexibility. Journal of Manufacturing Science and Engineering, 2016, 138(4): 041001CrossRefGoogle Scholar
  45. 45.
    Ma W, He G, Zhu L, et al. Tool deflection error compensation in five-axis ball-end milling of sculptured surface. International Journal of Advanced Manufacturing Technology, 2016, 84(5): 1421–1430Google Scholar
  46. 46.
    Shabouk S, Nakamoto T. Micro machining of single crystal diamond by utilization of tool wear during cutting process of ferrous material. Journal of Micromechatronics, 2002, 2(1): 13–26CrossRefGoogle Scholar
  47. 47.
    Kalpakjian S, Schmid S R. Manufacturing Processes for Engineering Materials. Upper Saddle River: Prentice Hall, 2007Google Scholar
  48. 48.
    Schaller T, Bohn L, Mayer J, et al. Microstructure grooves with a width of less than 50 mm cut with ground hard metal micro end mills. Precision Engineering, 1999, 23(4): 229–235CrossRefGoogle Scholar
  49. 49.
    Onikura H, Ohnishi O, Take Y, et al. Fabrication of micro carbide tools by ultrasonic vibration grinding. CIRP Annals—Manufacturing Technology, 2000, 49(1): 257–260CrossRefGoogle Scholar
  50. 50.
    Adams D P, Vasile M J, Benavides G, et al. Micromilling of metal alloys with focused ion beam—Fabricated tools. Precision Engineering, 2001, 25(2): 107–113CrossRefGoogle Scholar
  51. 51.
    Egashira K, Hosono S, Takemoto S, et al. Fabrication and cutting performance of cemented tungsten carbide micro-cutting tools. Precision Engineering, 2011, 35(4): 547–553CrossRefGoogle Scholar
  52. 52.
    Wong Y S, Rahman M, Lim H S, et al. Investigation of micro-EDM material removal characteristics using single RC-pulse discharges. Journal of Materials Processing Technology, 2003, 140(1–3): 303–307CrossRefGoogle Scholar
  53. 53.
    Pham D T, Dimov S S, Bigot S, et al. Micro-EDM—Recent developments and research issues. Journal of Materials Processing Technology, 2004, 149(1): 50–57CrossRefGoogle Scholar
  54. 54.
    Liao Y S, Chen S T, Lin C S, et al. Fabrication of high aspect ratio microstructure arrays by micro reverse wire-EDM. Journal of Micromechanics and Microengineering, 2005, 15(8): 1547–1555CrossRefGoogle Scholar
  55. 55.
    Wang J, Han F. Simulation model of debris and bubble movement in consecutive-pulse discharge of electrical discharge machining. International Journal of Machine Tools & Manufacture, 2014, 77: 56–65CrossRefGoogle Scholar
  56. 56.
    Kadirvel A, Hariharan P, Gowri S. A review on various research trends in micro-EDM. International Journal of Mechatronics and Manufacturing Systems, 2012, 5(5/6): 361–384CrossRefGoogle Scholar
  57. 57.
    Pham D T, Ivanov A, Bigot S, et al. An investigation of tube and rod electrode wear in micro EDM drilling. International Journal of Advanced Manufacturing Technology, 2007, 33(1–2): 103–109CrossRefGoogle Scholar
  58. 58.
    Pham D T, Ivanov A, Bigot S, et al. A study of micro-electro discharge machining electrode wear. Proceedings of the Institution of Mechanical Engineers. Part C, Journal of Mechanical Engineering Science, 2007, 221(5): 605–612CrossRefGoogle Scholar
  59. 59.
    Dimov S, Pham D T, Ivanov A, et al. Tool-path generation system for micro-electro discharge machining milling. Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture, 2003, 217(11): 1633–1637CrossRefGoogle Scholar
  60. 60.
    Tsai Y, Masuzawa T. An index to evaluate the wear resistance of the electrode in micro-EDM. Journal of Materials Processing Technology, 2004, 149(1–3): 304–309CrossRefGoogle Scholar
  61. 61.
    Uhlmann E, Roehner M. Investigations on reduction of tool electrode wear in micro-EDM using novel electrode materials. CIRP Journal of Manufacturing Science and Technology, 2008, 1 (2): 92–96CrossRefGoogle Scholar
  62. 62.
    Aligiri E, Yeo S H, Tan P C. A new tool wear compensation method based on real-time estimation of material removal volume in micro-EDM. Journal of Materials Processing Technology, 2010, 210(15): 2292–2303CrossRefGoogle Scholar
  63. 63.
    Bissacco G, Hansen H N, Tristo G, et al. Feasibility of wear compensation in micro EDM milling based on discharge counting and discharge population characterization. CIRP Annals—Manufacturing Technology, 2011, 60(1): 231–234CrossRefGoogle Scholar
  64. 64.
    Masuzawa T, Fujino M, Kobayashi K, et al. Wire electro-discharge grinding for micro-machining. CIRP Annals—Manufacturing Technology, 1985, 34(1): 431–434CrossRefGoogle Scholar
  65. 65.
    Rees A, Dimov S S, Ivanov A, et al. Micro-electrode discharge machining: Factors affecting the quality of electrodes produced on the machine through the process of wire electro-discharge machining. Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture, 2007, 221(3): 409–418CrossRefGoogle Scholar
  66. 66.
    Uhlmann E, Piltz S, Jerzembeck S. Micro-machining of cylindrical parts by electrical discharge grinding. Journal of Materials Processing Technology, 2005, 160(1): 15–23CrossRefGoogle Scholar
  67. 67.
    Qu J, Shih A J, Scattergood R O. Development of the cylindrical wire electrical discharge machining process, Part 1: Concept, design, and material removal rate. Journal of Manufacturing Science and Engineering, 2002, 124(3): 702–707CrossRefGoogle Scholar
  68. 68.
    Qu J, Shih A J, Scattergood R O. Development of the cylindrical wire electrical discharge machining process, Part 2: Surface integrity and roundness. Journal of Manufacturing Science and Engineering, 2002, 124(3): 708–714CrossRefGoogle Scholar
  69. 69.
    Rees A, Brousseau E, Dimov S S, et al. Wire electro discharge grinding: surface finish optimisation. Multi-Material Micro Manufacture, 2008, 1–4Google Scholar
  70. 70.
    Meijer J. Laser beam machining (LBM), state of the art and new opportunities. Journal of Materials Processing Technology, 2004, 149(1–3): 2–17CrossRefGoogle Scholar
  71. 71.
    Knowles M R H, Rutterford G, Karnakis D, et al. Micro-machining of metals, ceramics and polymers using nanosecond lasers. International Journal of Advanced Manufacturing Technology, 2007, 33(1–2): 95–102CrossRefGoogle Scholar
  72. 72.
    Rizvi N H, Apte P. Developments in laser micro-machining techniques. Journal of Materials Processing Technology, 2002, 127 (2): 206–210CrossRefGoogle Scholar
  73. 73.
    Pham D T, Dimov S S, Ji C, et al. Laser milling as a ‘rapid’ micromanufacturing process. Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture, 2004, 218(1): 1–7CrossRefGoogle Scholar
  74. 74.
    Corcoran A, Sexton L, Seaman B, et al. The laser drilling of multilayer aerospace material systems. Journal of Materials Processing Technology, 2002, 123(1): 100–106CrossRefGoogle Scholar
  75. 75.
    Matsuoka Y, Kizuka Y, Inoue T. The characteristics of laser micro drilling using a Bessel beam. Applied Physics. A, Materials Science & Processing, 2006, 84(4): 423–430CrossRefGoogle Scholar
  76. 76.
    Biswas R, Kuar A S, Sarkar S, et al. A parametric study of pulsed Nd: YAG laser micro-drilling of gamma-titanium aluminide. Optics & Laser Technology, 2010, 42(1): 23–31CrossRefGoogle Scholar
  77. 77.
    Zheng H Y, Huang H. Ultrasonic vibration-assisted femtosecond laser machining of microholes. Journal of Micromechanics and Microengineering, 2007, 17(8): N58–N61CrossRefGoogle Scholar
  78. 78.
    Mao C, Sun X, Huang H, et al. Characteristics and removal mechanism in laser cutting of cBN-WC-10Co composites. Journal of Materials Processing Technology, 2016, 230: 42–49CrossRefGoogle Scholar
  79. 79.
    Petkov P V, Dimov S S, Minev R M, et al. Laser milling: Pulse duration effects on surface integrity. Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture, 2008, 222(1): 35–45CrossRefGoogle Scholar
  80. 80.
    Preuss S, Demchuk A, Stuke M. Sub-picosecond UV laser ablation of metals. Applied Physics. A, Materials Science & Processing, 1995, 61(1): 33–37CrossRefGoogle Scholar
  81. 81.
    von der Linde D, Sokolowski-Tinten K. The physical mechanisms of short-pulse laser ablation. Applied Surface Science, 2000, 154–155: 1–10CrossRefGoogle Scholar
  82. 82.
    Kautek W, Krueger J. Femtosecond pulse laser ablation of metallic, semiconducting, ceramic, and biological materials. Laser Materials Processing: Industrial and Microelectronics Applications, 1994, 600–611CrossRefGoogle Scholar
  83. 83.
    Huang H, Zheng H Y, Lim G C. Femtosecond laser machining characteristics of Nitinol. Applied Surface Science, 2004, 228(1–4): 201–206CrossRefGoogle Scholar
  84. 84.
    Dobrev T, Dimov S S, Thomas A J. Laser milling: Modelling crater and surface formation. Proceedings of the Institution of Mechanical Engineers. Part C, Journal of Mechanical Engineering Science, 2006, 220(11): 1685–1696CrossRefGoogle Scholar
  85. 85.
    Pham D T, Dimov S S, Petkov P V. Laser milling of ceramic components. International Journal of Machine Tools & Manufacture, 2007, 47(3–4): 618–626CrossRefGoogle Scholar
  86. 86.
    Kim C S, Ahn S H, Jang D Y. Review: Developments in micro/nanoscale fabrication by focused ion beams. Vacuum, 2012, 86(8): 1014–1035CrossRefGoogle Scholar
  87. 87.
    Tseng A A. Recent developments in micromilling using focused ion beam technology. Journal of Micromechanics and Microengineering, 2004, 14(4): R15–R34CrossRefGoogle Scholar
  88. 88.
    Tseng A A. Recent developments in nanofabrication using focused ion beams. Small, 2005, 1(10): 924–939CrossRefGoogle Scholar
  89. 89.
    Sugiyama M, Sigesato G. A review of focused ion beam technology and its applications in transmission electron microscopy. Journal of Electron Microscopy, 2004, 53(5): 527–536CrossRefGoogle Scholar
  90. 90.
    Ahn S H, Chun D M, Kim C S. Nanoscale hybrid manufacturing process by nano particle deposition system (NPDS) and focused ion beam (FIB). CIRP Annals—Manufacturing Technology, 2011, 60(1): 583–586CrossRefGoogle Scholar
  91. 91.
    Ding X, Lim G C, Cheng C K, et al. Fabrication of a micro-size diamond tool using a focused ion beam. Journal of Micromechanics and Microengineering, 2008, 18(7): 075017CrossRefGoogle Scholar
  92. 92.
    Picard Y N, Adams D P, Vasile M J, et al. Focused ion beamshaped microtools for ultra-precision machining of cylindrical components. Precision Engineering, 2003, 27(1): 59–69CrossRefGoogle Scholar
  93. 93.
    Shim S, Bei H, Miller M K, et al. Effects of focused ion beam milling on the compressive behavior of directionally solidified micropillars and the nanoindentation response of an electropolished surface. Acta Materialia, 2009, 57(2): 503–510CrossRefGoogle Scholar
  94. 94.
    Xu Z, Fang F, Zhang S, et al. Fabrication of micro DOE using micro tools shaped with focused ion beam. Optics Express, 2010, 18(8): 8025–8032CrossRefGoogle Scholar
  95. 95.
    Wu W, Xu Z, Fang F, et al. Decrease of FIB-induced lateral damage for diamond tool used in nano cutting. Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms, 2014, 330: 91–98CrossRefGoogle Scholar
  96. 96.
    Li W, Minev R, Dimov S, et al. Patterning of amorphous and polycrystalline Ni 78 B 14 Si 8 with a focused-ion-beam. Applied Surface Science, 2007, 253(12): 5404–5410CrossRefGoogle Scholar
  97. 97.
    Li W, Lalev G, Dimov S, et al. A study of fused silica micro/nano patterning by focused-ion-beam. Applied Surface Science, 2007, 253(7): 3608–3614CrossRefGoogle Scholar
  98. 98.
    Wu S E, Liu C P. Direct writing of Si island arrays by focused ion beam milling. Nanotechnology, 2005, 16(11): 2507–2511CrossRefGoogle Scholar
  99. 99.
    Chang T C, Hong K B, Lai Y Y, et al. ZnO-based microcavities sculpted by focus ion beam milling. Nanoscale Research Letters, 2016, 11(1): 319–325CrossRefGoogle Scholar
  100. 100.
    Lu M, Russell H, Huang H. Fracture strength characterization of protective intermetallic coatings on AZ91E Mg alloys using FIBmachined microcantilever bending technique. Journal of Materials Research, 2015, 30(10): 1678–1685CrossRefGoogle Scholar

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© The Author(s) 2017

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  1. 1.School of Mechanical and Mining EngineeringThe University of QueenslandQLDAustralia
  2. 2.Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of EducationDalian University of TechnologyDalianChina

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