Product Code: JLA_15_2_101

Authors:
M. El-Bandrawy
K. Nagarathnam
Mool C. Gupta
Applied Research Center, College of Engineering and Technology, Old Dominion University, Newport News, Virginia 23606

C. Hamann
J. Horsting
Siemens Automotive, Newport News, Virginia 23606

A copper vapor laser (CVL) of 511/578 nm wavelength, 25 ns pulse width, and 10 kHz repetition rate combined with a computer controlled galvo head was used for laser micromachining of 304 stainless steel. The objective of this study was to develop the CVL micromachining process and its optimization. We observed a significant improvement in micromachining quality with a spatially filtered beam. Micromachining experiments were carried out on stainless steel strip samples of 75, 153, and 356 μm thickness. We studied the ablation rate using a single pulse and monitored the heat affected zone (HAZ) as a function of the applied laser power density. The ablated volume and HAZ are directly proportional to the applied laser power density for low to medium laser powers (up to 2×10¹³ W/m²). The ranges of HAZ diameter and ablated volume were 15.3–28.7 μm and 112.8–537.6 μm³, respectively, for the applied power density in the range of 1.0–63.7×10¹³ W/m². The roughness created by ablation process was studied at various pulse overlaps at laser power density of 87.8×10¹³ W/m². Ablation depth and surface roughness were found to be inversely proportional to the center-to-center pulse overlap and directly proportional to the power density. © 2003 Laser Institute of America.