Possibility to machine the metallic materials by means of a laser beam depends on the capacity of these materials to
absorb the respective laser radiation. In the case of a laser beam heaving a wave length λ=1070 nm, the experimental
researches showed that among the common metallic materials, the steel absorbs the laser radiation, allowing the applying of some laser beam machining processes, while the copper, the aluminum and the bronze cannot be machined by means of the laser, for an output power of the laser equipment up to 300 W. Due to their high capacity to reflect the above mentioned laser radiation, such metallic materials (aluminum, copper, brass) cannot be significantly affected by the laser beam action and, therefore, they could not be machined by means of the laser radiation having a wave length of 1070 nm. Some considerations were elaborated by taking into account the phenomena developed at the contact zone between the laser beam and the surface layer of the workpiece. A part of the laser beam energy is absorbed, determining the material melting and vaporizing; another part of the laser beam is reflected by the workpiece surface in the case of copper, aluminum and brass. Some explanations concerning the effect of the laser beam exploited during the laser beam machining were developed, inclusively by means of the thermal properties of the workpiece materials.
In the case of the electrical discharge machining, the obtained surface is a concatenation of craters generated by the electrical discharges. The dimensions of the crater generated by a single electrical discharge could offer an image concerning the material behavior during the electrical discharge machining and the phenomena corresponding to this machining technique. To ensure better conditions for the experiments development, a research schema based on the initiation of the single electrical discharge between the rectilinear edges of two parallelipiedic bars placed in plans perpendicular each other was applied. A factorial experiment with two independent variables at two levels was used to establish an empirical relation type power; the relation emphasizes the influence exerted by the voltage and by the capacity of the relaxation circuit on the dimensions of the crater. The sizes of the exponents proves the bigger influence exerted by the input factors on the crater width.