Abrasive water jet cutting (AWJ) is a very versatile technology, but it is limited by a relative poor accuracy. Source of relative poor accuracy lies the geometrically non-defined and flexible tool and gradual focusing nozzle wear. As focusing nozzle diameter increases, the AWJ diameter and kerf also increase, which reduces accuracy of the cut. There is currently no device on the market that would enable monitoring focusing nozzle wear.
Master’s thesis investigates the development of a prototype used for monitoring focusing nozzle wear and setting the correct offset in order to achieve desired tolerances. Measuring focusing nozzle wear was achieved by measuring AWJ diameter and rate of jet disintegration with through beam laser sensor. Since formation and geometrical properties of AWJ and greatly dependant on inner geometry of focusing nozzle, focusing nozzle wear can be determined by measuring jet geometry. Experiments were conducted using five differently worn nozzles at different water pressures, with and without abrasive, at different lengths of measurement time and at different standoff distances. To determine the correct offset, kerf was measured on different test cuts. Test cuts were done using five differently worn nozzles with different cut materials.
Result of master’s thesis is a device that is capable of monitoring focusing nozzle wear and setting the correct offset before or after every operation.