Laser Microdrilling of Thermal Barrier Coatings

AbstractParametric study of laser microdrilling of Ytrria stabilized Zirconia coated titanium plates employing 12kW CO2 laser was conducted in order to investigate the influence of laser power, frequency and assist gas pressure on quality characteristics such as spatter deposition area, entrance circularity, entrance and exit diameter and taper. Spatter deposition area was found significantly influenced by laser power. Entrance circularity and entrance diameter was influenced by assist gas pressure. Exit diameter was influenced by both laser power and assist gas pressure. Taper angle was influenced by assist gas pressure. Multi objective optimization using Grey Relational Analysis indicated that minimum spatter deposition (19.1152mm2), nominal entrance circularity (0.8709), entrance hole diameter (1mm) and exit hole diameter (0.5709) and minimum taper angle (2.1421°) corresponded to 2000W laser power, 10kHz frequency and 5bar assist gas pressure