Abtragen mit Laserstrahlung

Several physical processes are involved in the process of material removal by laser light. The energy transferred to the workpiece is determined by the intensity of the impinging laser light and by the absorption at the workpiece. The material can be removed by expulsion of the liquid phase or by evaporation. The melt is normally removed by use of a gas jet which is applied to the laser-treated area. The amount of material which can be removed by the gas jet dominantly determines the material removal rate. For a precise material removal the material has to be evaporated. In this case a much higher amount of energy has to be applied. A part of the energy which is transferred to the workpiece is transported by heat conduction to regions of the workpiece which are not going to be removed. In order to minimize these energy losses the laser intensity should be as high as possible while reducing the exposure time. On the other hand, the intensity must not exceed the plasma shielding limit. T he optimization of the process of material removal by laser light requires knowledge on the physical processes mentioned above. Therefore, this physical processes are outlined in the following.