A basic study toward automated sorting of aluminum scraps

It is important to develop an effective sorting system for reducing cascade use of aluminum scraps by returning the scraps to wrought aluminum. A feasibility study has been conducted to develop a new sorting process for aluminum scraps. The process includes irradiation of the aluminum surface by YAG laser, that is an automatic discrimination method by a pattern matching method. Seven aluminum alloys selected from seven wrought aluminum alloy systems were used for sorting test samples. The YAG laser beam was irradiated to melt the surface of the aluminum. The surface morphology after irradiation was observed including the molten area, brightness profile and change in color. The surface morphology seemed to depend on the physical properties of aluminum such as thermal conductivity. The possibility of establishing the automated aluminum sorting method was suggested by the pattern matching method which effectively identifies the aluminum alloy number.