During AWJ cutting process, water under high speed is injected through an orifice into the cutting head, which accelerates abrasive particles through the focusing nozzle. Due to the high kinetic energy of the resulting jet, the inside of the focusing nozzle wears out and cutting accuracy is reduced. In this master's thesis an instrument for automated measuring of the jet diameter at different standoff distances is developed, where a thru-beam laser system is used as a measuring device. Measurements were performed with five differently worn nozzles at 275 MPa water pressure, with open and closed abrasive inlet and with two different cutting heads. By measuring the jet diameter at multiple standoff distances we investigated how diameter changes with increasing standoff distance and how nozzle wear can be attributed to the shape of the jet.
|