Description of the processCopyright: Fraunhofer ILT
Drillings in the mm to µm range can be realized by either single pulse drilling, percussion drilling, trepanning or helical drilling. Depending on the required quality (precision) and productivity (drilling time), one of the mentioned drilling techniques needs to be used. Drilling with laser radiation is an alternative solution competing with electron-beam drilling, electro-discharge drilling, electrochemical drilling and ultrasonic drilling. Laser radiation as a tool for manufacturing is preferably applied on hard material (e.g. ceramics and high-hardness steel), when a high productivity is required, or to drill very small holes (diameter < 100 µm) in a defined angle of inclination (e.g. aerodynamic flows).
Laser drilling requires high standards of reproducibility, drilling speed and the achievable aspect ratio (ratio drilled-hole-to-diameter). The most important challenges to this method are the minimization of the recast and formation of bursts as well as the reduction of the number and length of micro cracks.
In order to meet these requirements, the drilling is constantly monitored with different means of diagnosis. Additionally the drilled holes are evaluated by metallography, microscopy and high-speed photography for comparing with precedent simulations and theoretical models.
Fields of application
Industrial fields of applications of metal drilling are automotive engineering, aerospace and power generation. It may be used to create components like injection nozzles, fuel filters, turbine parts, and multilayer-systems. The trend to miniaturize in electrical engineering requires special processing techniques, e.g. the drilling of micro-holes (Mikrovias) in printed circuit boards. In medical technology the laser radiation is used to produce surgery tools, e.g. suture carrier needles, as well as for laser surgery applications, e.g. drilling and ablation of ossicles.