Description

Selective laser melting (SLM) is a method of performing additive manufacturing by selectively irradiating a required portion of metal powder spread on a vertical drive stage with laser for melting and solidifying the powder. By using this method, it is possible to fabricate metal structures of arbitrary shapes based on 3D modeling data. Near-infrared lasers, which are mainly used in the SLM method at present, have low absorption rate to copper, making it difficult to form a 3D structure of copper. To solve this problem, we have developed a new 200W blue diode laser (wavelength: 450nm) having a high absorption rate to copper. The SLM system with blue diode laser has been developed.

In addition, the additive manufacturing of pure copper was performed under the control of parameters such as sweep speed and hatching interval. Because, the purpose of this study is to fabricate a high density 3D structure of pure copper.

The fabricated 5mm x 5mm x 5mm size sample was cut perpendicular to the sweep direction, polished and observed to measure the filling rate of the cross-section. The cross-section observation image of the sample was binarized with the copper portion being white and the other portions being black, and the proportion of copper in the shaped body was defined as the filling rate.

In the beginning of the experiment, voids appeared in the body of the copper 3D structure with the cross-section filling rate of approximately 92%. Therefore, we changed the parameters to suppress the void formation in the process. Although we focused on the filling rate of the structure for achieving the purpose, the filling rate did not increase easily. Therefore, we changed the sweeping pattern of the laser irradiation. As a result of the optimization of the process parameters, especially by the effect of the optimization of the sweeping method, a high density structure of the filling rate of approximately 99.1% was achieved.

Contributing Authors

  • Eiji Hori
    Osaka University
  • Masahiro Tsukamoto
    Osaka University
  • Yuji Sato
    Osaka University
Eiji Hori
Osaka University
Track: Laser Additive Manufacturing
Session: Direct Energy Deposition Process Technology
Day of Week: Monday
Date/Time:
Location:

Keywords

  • Additive Manufacturing
  • Blue Diode Laser
  • Pure Copper
  • Slm