Product Code: JLA_17_3_136

Authors:
Huan Qi
Jyoti Mazumder
Center for Laser Aided Intelligent Manufacturing, Department of Mechanical Engineering, The University of Michigan, Ann Arbor, Michigan 48109

Larry Green
Spiricon, Inc., Logan, Utah 84341

Gary Herrit
II-VI, Inc., Saxonburg, Pennsylvania 16056

The quality of a laser beam profile and its stability play fundamental roles in laser material processing. Beam reflections may dramatically affect the beam quality under certain material processing conditions. In this study, experiments were carried out to examine the variations of the continuous wave CO₂ laser beam profile during the direct metal deposition (DMD) process. A pyroelectric-camera-based new industrial laser beam analysis device was installed in the optical line near the laser output coupler. Experimental results are presented with the comparison of beam profiles under different cladding processing conditions, such as the coaxial powder flow cladding, preplaced powder cladding, the remelting process, and the dumping of the raw beam. It was observed that cladding using preplaced powder gives off more reflective energy from the cladding zone which deforms the beam profile and causes great power fluctuation. Laser beam profiles and stability during DMD processes were monitored and analyzed with various processing geometries and the identification of porosity formation. High contents of the oxidized contaminants in the reused H13 powder were found to cause dark discontinuities in single track cladding where obvious beam power fluctuations were observed. In multiple layer cladding, 7%–20% more reflected energy was detected in the first layer deposition than in the successive layers.