Some Fundamental Properties of High Power CO_2, Laser Beam as a Heat Source
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The interaction between the metallic material and focused CO_2 laser beam with power level of several hundred watts is studied. The energy density distribution of the focused CO_2 laser used in this experiment can be approximated by a Gaussian curve with a diameter of 0.5mm at e^<-1> power point. The beam absorptance of polished metal is low and only about 10% at most, in proportion to square root of dc specific, resitivity of metal. A weldability of metal by CO_2 laser is proportional to ak^<3/2> θ_f under the polished surface condition, and is to akθ_f under the condition of the 100% absorptance. The interaction between the focused laser beam and metallic specimen with various surface conditions based on measurements of the beam absorptance and the temperature, observation by means of high speed camera and analysis of heat conduction. As a results, it was found that in order to enhance the beam absortance the surface treatment was effective. The effect of the surface treatment on the beam absorptance becomes larger with lower melting point θ_f of and higher thermal conductivity k of the metal and higher boiling point of the treated surface layer, and under such a condition the absorptance is almost the same in different surface treatments. Examples laser-processed are shown.
- Transactions of JWRI
Transactions of JWRI 3(1), 1-20, 1974-02