Description

Pure copper has been used in many industrial components such as an automotive motor and a heat exchanger because of its high electrical and thermal conductivity. The heat exchanger and automotive motor for next generation require more complex shape to improve the performance. Laser metal deposition (LMD) method is one of additive manufacturing technologies, which is suitable for making metal objects with complex shape rapidly. However, it is difficult to process pure copper by LMD method because of the light absorptivity. Conventional LMD usually employed near infrared ray (NIR) laser at a wavelength of 900 to 1100 nm. The light absorptivity of pure copper in the NIR region is only 10 %. Compared with NIR laser, light absorptivity in blue region at the wavelength of 450 nm is about 60%, six times higher than that of NIR. Thus, we have developed a multi beam LMD system with blue diode lasers instead of NIR lasers which enable to melt powders with thin molten pool called molten layer. In this study, we tried to form a three dimensional object production of pure copper rod by LMD method with blue diode lasers. In order to clarify the mechanism of a rod formation, the melting and solidification process during a rod formation was captured with a high-speed video camera. Furthermore, cross section of pure copper was observed and evaluate the pore generation or cross-sectional shape to clarify the forming mechanism. In addition, an evaluation of electric resistivity and elemental analysis were conducted with electron probe micro analyzer. As results, a pure copper rod with a length of 100 mm was successfully formed in 25 seconds. It is revealed the relationship between the laser spot shape and the cross sectional shape of the rod. The electric resistivity of the rod was almost same as 99.99 % pure copper wire.

Contributing Authors

  • Kazuhiro Ono
    Graduate School of Engineering, Osaka University
  • Yuji Sato
    Joining and Welding Research Institute, Osaka University
  • Ritsuko Higashino
    Joining and Welding Research Institute, Osaka University
  • Kento Morimoto
    Graduate School of Engineering, Osaka University
  • Yoshinori Funada
    Industrial Research Institute of Ishikawa
  • Nobuyuki Abe
    Joining and Welding Research Institute, Osaka University
  • Masahiro Tsukamoto
    Joining and Welding Research Institute, Osaka University
Kazuhiro Ono
Graduate School of Engineering, Osaka University
Track: Laser Materials Macroprocessing
Session: Poster
Date/Time:
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Keywords

  • Blue Diode Laser
  • Laser Metal Deposition
  • Pure Copper