An experimental investigation of the airflow characteristics of laser drilled holes Available to Purchase

When using a laser process for the creation of holes to be used in film cooling applications, the mass flow rate is a critical factor in judging hole quality. In the present study, an experimental investigation was undertaken to identify the importance of laser drilling process parameters on the hole airflow. The total mass flow rate through a hole is a function of the aerodynamic losses resulting from both frictional effects and geometric features of the hole inlet and exit. Optimum aerodynamic performance depends upon the proper selection of laser drilling process parameters. Using a four parameter, two level test matrix, process boundaries were examined. These parameters included laser power, laser beam focus, laser beam aperture, and workpiece thickness. Laser beam focus was determined to be the most effective individual parameter, followed by workpiece thickness. Laser beam aperture was the least effective parameter. Interactions between laser beam focus, workpiece thickness, and laser power were found to produce the largest change in the hole flow rate. Flow rate variations among three sample sets were also significant.