Smart laser micro-welding of difficult-to-weld materials for electronic industry

Y. Okamoto, N. Nishi, S. Nakashiba, T. Sakagawa, A. Okada

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Citations (Scopus)


It has been known that wavelength, power density, interaction time and material properties have great influence on processing characteristics in laser material processing, in which materials with higher reflectivity classify into difficulttoweld materials. In electronic industry, aluminum alloy is widely used as structural components due to its high specific strength, and copper became an important material because of its excellent electrical conductivity. These materials have high reflectivity and high thermal conductivity, which results in instability of energy absorption and processing results. Therefore, welding defects might be noticed in the micro-joining of aluminum alloy and copper. In this paper, the smart laser micro-welding of difficult-to-weld materials such as aluminum alloy and copper were discussed. The combination of a pulsed Nd:YAG laser and a continuous diode laser could perform high-performance micro-welding of aluminum alloy. A pulsed Nd:YAG laser was absorbed effectively from the beginning of laser scanning by pre-heating Nd:YAG laser pulse with the superposition of continuous diode laser, and wide and deep weld bead could be obtained with better surface integrity. As for micro-welding of copper material, stable absorption state could be achieved using a pulsed green Nd:YAG laser, since its absorptivity showed almost constant values with change of power density. A longer pulse duration was effective to achieve not only high absorptivity but also low deviation of absorptivity. The pulse waveform with maximum peak at the early period and a long pulse duration led to stabilizing the penetration depth with less porosity.

Original languageEnglish
Title of host publicationLaser-Based Micro- and Nanoprocessing IX
EditorsUdo Klotzbach, Kunihiko Washio, Craig B. Arnold
ISBN (Electronic)9781628414417
Publication statusPublished - Jan 1 2015
EventLaser-Based Micro- and Nanoprocessing IX - San Francisco, United States
Duration: Feb 10 2015Feb 12 2015

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherLaser-Based Micro- and Nanoprocessing IX
Country/TerritoryUnited States
CitySan Francisco


  • Absorptivity
  • Aluminum alloy
  • Copper
  • Difficult-to-weld
  • Green pulsed laser
  • Micro-welding
  • Pre-heating

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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