Microfluidics and Nanofluidics

, Volume 14, Issue 1–2, pp 101–111 | Cite as

A novel technique for producing metallic microjets and microdrops

  • E. J. Vega
  • A. M. Gañán-Calvo
  • J. M. MontaneroEmail author
  • M. G. Cabezas
  • M. A. Herrada
Research Paper


A new technique for producing steady metallic jets is proposed. It allows the production of supercritical jets with Weber numbers well below unity, which entails important technological advantages over existing techniques. The metallic liquid is injected through a micrometer converging nozzle located inside a gas stream. Both the liquid jet and the coflowing gas current cross an orifice located in front of the nozzle. The gas stream stabilizes the jet by sweeping away the capillary waves growing on the free surface. In this way, one can steadily produce microjets with a kinetic energy much lower than the interfacial energy, a possibility that has been predicted theoretically (Gañán-Calvo in Phys Rev E 78:026304, 2008). Experiments were conducted with mercury to assess the performance of the new technique. The experimental results agreed remarkably well with the predictions calculated from the convective/absolute instability transition of the jet. The jet breakup mechanism did not correspond to classical Rayleigh instability, but to the growth of surface waves over a capillary column which ends at a fixed location. The results were compared with those obtained with the well-established flow focusing method to show that the new technique considerably favors the jet’s stability.


Surf-jetting Metallic microjets Coflowing systems Additive manufacturing Flow focusing 



Partial support from the Ministry of Science and Education, Junta de Extremadura, and Junta de Andalucí a (Spain) through Grant Nos. DPI2010-21103, GR10047, and P08-TEP-04128, respectively, is gratefully acknowledged.


  1. Basaran OA (2002) Small-scale free surface flows with breakup: drop formation and emerging applications. AlChE J 48:1842–1848CrossRefGoogle Scholar
  2. Briggs RJ (1964) Electron–stream interaction with plasmas. MIT Press, CambridgeGoogle Scholar
  3. Christopher GF, Anna SL (2007) Microfluidic methods for generating continuous droplet streams. J Phys D Appl Phys 40:R319–R336CrossRefGoogle Scholar
  4. Gañán-Calvo AM (1998) Generation of steady liquid microthreads and micron-sized monodisperse sprays in gas streams. Phys Rev Lett 80:285–288CrossRefGoogle Scholar
  5. Gañán-Calvo AM (2008) Unconditional jetting. Phys Rev E 78:026304CrossRefGoogle Scholar
  6. Gañán-Calvo AM, Montanero JM (2009) Revision of capillary cone-jet physics: electrospray and flow focusing. Phys Rev E 79:066305CrossRefGoogle Scholar
  7. Ghafouri-Azar R, Shakeri S, Chandra S, Mostaghimi J (2003) Interactions between molten metal droplets impinging on a solid surface. Int J Heat Mass Transf 46:1395–1407CrossRefGoogle Scholar
  8. Gibson I, Rosen DW, Stucker B (2010) Additive manufacturing technologies. Springer, BerlinCrossRefGoogle Scholar
  9. Herrada MA, Gañán-Calvo AM, Ojeda-Monge A, Bluth B, Riesco-Chueca P (2008) Liquid flow focused by a gas: jetting, dripping, and recirculation. Phys Rev E 78:036323CrossRefGoogle Scholar
  10. Holgado MA, Arias JL, Cózar MJ, Alvarez-Fuentes J, Gañán-Calvo A, Fernández-Arévalo M (2008) Synthesis of lidocaine-loaded plga microparticles by flow focusing. Effects on drug loading and release properties. Int J Pharm 358:27–35CrossRefGoogle Scholar
  11. Huang SH, Tan WH, Tseng FG, Takeuchi S (2006) A monolithically three-dimensional flow-focusing device for formation of single/double emulsions in closed/open microfluidic systems. J Micromech Microeng 16:2336–2344CrossRefGoogle Scholar
  12. Huerre P, Monkewitz PA (1990) Local and global instabilities in spatially developing flows. Annu Rev Fluid Mech 22:473–537MathSciNetCrossRefGoogle Scholar
  13. Jiang XS, Qi LH, Luo J, Zhou HHJM (2010) Research on accurate droplet generation for micro-droplet deposition manufacture. Int J Adv Manuf Technol 49:535–541CrossRefGoogle Scholar
  14. Lee TK, Kang TG, Yang JS, Jo J, Kim KY, Choi BO, Kim DS (2008) Drop-on-demand solder droplet jetting system for fabricating microstructure. IEEE Trans Electron Packag Manuf 31:202–210CrossRefGoogle Scholar
  15. Lehuaa Q, Xiaoshana J, Juna L, Xianghui H, Hejun L (2010) Dominant factors of metal jet breakup in micro droplet deposition manufacturing technique. Chin J Aeronaut 23:495–500CrossRefGoogle Scholar
  16. Luo J, Qi LH, Jiang XS, Zhou JM, Huang H (2008) Research on lateral instability of the uniform-charged droplet stream during droplet-based freeform fabrication. Int J Mach Tools Manuf 48:289–294CrossRefGoogle Scholar
  17. Montanero JM, Gañán-Calvo AM, Acero AJ, Vega EJ (2010) Micrometer glass nozzles for flow focusing. J Micromech Microeng 20:075035CrossRefGoogle Scholar
  18. Montanero JM, Rebollo-Muñoz N, Herrada MA, Gañán-Calvo AM (2011) Global stability of the focusing effect of fluid jet flows. Phys Rev E 82:036309Google Scholar
  19. Orme M, Bright A (2000) Recent advances in highly controlled molten metal droplet formation from capillary stream break-up with applications to advanced manufacturing. In: Warrendale PT (ed) Liquid metal atomization: fundamentals and practice: proceedings of a symposium held during the 2000 TMS Annual Meeting, Nashville, pp 157–168Google Scholar
  20. Orme M, Courter J, Liu Q, Huang C, Smith R (2000) Electrostatic charging and deflection of nonconventional droplet streams formed from capillary stream breakup. Phys Fluids 12:2224–2235CrossRefGoogle Scholar
  21. Otsu N (1979) A threshold selection method from gray-level histograms. IEEE Trans Syst Man Cybern 9:62–66CrossRefGoogle Scholar
  22. Rayleigh L (1879) On the instability of jets. Proc Lond Math Soc 10:4–13zbMATHCrossRefGoogle Scholar
  23. Varentsov VL (2011) Numerical investigations of the WASA pellet target operation and proposal of a new technique for the PANDA pellet target. Nucl Instr Meth Phys Res A 646:12–21CrossRefGoogle Scholar
  24. Vega EJ, Montanero JM, Herrada MA, Gañán-Calvo AM (2010) Global and local instability of flow focusing: the influence of the geometry. Phys Fluids 22:064105CrossRefGoogle Scholar
  25. Vega EJ, Gañán-Calvo AM, Montanero JM, Cabezas MG, Herrera MA (2012) Procedimiento y dispositivo para microfabricación y micro-soldadura. Patente de Invención P201200170Google Scholar
  26. Wang SP, Wang GX, Matthys EF (1998) Melting and resolidification of a substrate in contact with a molten metal: operational maps. Int J Heat Mass Transf 41:1177–1188zbMATHCrossRefGoogle Scholar
  27. Wang W, Lambert RA, Rangel R (2008) Parametric study of multi-splat solidification/remelting including contact resistance effects. Int J Heat Mass Transf 51:4811–4819zbMATHCrossRefGoogle Scholar
  28. Yingxue Y, Shengdong G, Chengsong C (2004) Rapid prototyping based on uniform droplet spraying. J Mater Process Technol 146:389–395CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • E. J. Vega
    • 1
  • A. M. Gañán-Calvo
    • 2
  • J. M. Montanero
    • 1
    Email author
  • M. G. Cabezas
    • 1
  • M. A. Herrada
    • 2
  1. 1.Departamento de Ingeniería Mecánica, Energética y de los MaterialesUniversidad de ExtremaduraBadajozSpain
  2. 2.Departamento de Mecánica de Fluidos e Ingeniería AeroespacialUniversidad de SevillaSevillaSpain

Personalised recommendations