Machining With Super-Pressure (690-MPa) Waterjets

This paper addresses waterjet cutting at pressures up to 690 MPa. Commercially available systems are capable of working at a maximum pressure of 379 MPa. A data matrix was generated to study the effects of waterjet parameters on cutting results. It was observed that thin sheet metal (1.6 mm thick) can effectively be cut with waterjets. Higher quality surfaces are produced as the pressure increases. It was also observed that excessive plastic deformation occurs near the edges. Several composites were cut at 690 MPa without the delaminations observed at 379 MPa. Increasing the standoff distance increases the cutting speed. This is attributed to the droplet impact effect that becomes dominant at large standoff distances. The use of 0.025-mm-diameter jets was explored. Tests were also conducted to include cutting with up to 690-MPa AWJs. Cuts with 690-MPa AWJs confirmed the linear trend of the effect of pressure on cutting rate. Most importantly, the abrasive consumption was significantly reduced when 690-MPa jets were used.