Geometrical aspects of laser-drilled high precision holes for flow control applications

Abstract

Laser drilling has become a valuable tool for the manufacture of high precision micro holes in a variety of materials. Laser drilled precision holes have applications in the automotive, aerospace, medical and sensor industry for flow control applications. The technology is competing with conventional machining micro electro-discharge machining in the field of fuel injection nozzle for combustion engines. Depending on the application, laser and optics have to be chosen which suits the requirements. In this paper, the results achieved with different lasers and drilling techniques will be compared to the hole specifications in flow control applications. The issue of geometry control of high aspect ratio laser drilled holes in metals will be investigated. The comparison of flow measurement results to microscopic hole dimension measurement show that flow characteristics strongly depend on cavitation number during flow.