Thermal analysis of gas assisted low power laser drilling of metals

R. S. Patel, M. Q. Brewster

Research output: Contribution to conferencePaper

Abstract

A theoretical model for gas assisted low power lasermetal interaction is developed. The steady state, one dimensional heat transfer and axisymmetric flow equations for the gas and molten metal regions are solved to obtain the melting front velocity. The model is based on the mechanism of gas-assisted molten metal expulsion and does not apply to situations where incident laser fluxes are high enough to produce significant vaporization at the metal surface. An analytical Solution for the temperature distribution in solid and molten metal regions is obtained, where as a fourth order Runge-Kutta numerical method is used to solve the nonlinear momentum equations. The time required to drill a hole in sheets of aluminum and copper for both argon and oxygen assist gases is obtained. In the case of oxygen assisted drilling the effects of change in absorptivity of the surface due to the oxide formation and the difference in the melting point of the oxide and metal are considered. The competing effect of these two factors determines whether use of oxygen as an assist gas improves the process efficiency or not. The model is compared with experimental values of the drilling time obtained using a Nd-Yag laser and reasonable qualitative agreement is found, although better quantitative agreement could be obtained by adjusting the absorptivity. The effect of incident laser flux on melting front velocity, liquid layer thickness, surface temperature, and drilling time under argon and oxygen assist gas cases is also presented and discussed.

Original languageEnglish (US)
StatePublished - Jan 1 1989
EventAIAA 20th Fluid Dynamics, Plasma Dynamics and Lasers Conference, 1989 - Buffalo, United States
Duration: Jun 12 1989Jun 14 1989

Other

OtherAIAA 20th Fluid Dynamics, Plasma Dynamics and Lasers Conference, 1989
CountryUnited States
CityBuffalo
Period6/12/896/14/89

ASJC Scopus subject areas

  • Aerospace Engineering
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Engineering (miscellaneous)

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    Patel, R. S., & Brewster, M. Q. (1989). Thermal analysis of gas assisted low power laser drilling of metals. Paper presented at AIAA 20th Fluid Dynamics, Plasma Dynamics and Lasers Conference, 1989, Buffalo, United States.