Patent ID: 7585201

Claim:
A water jet processing method using a water jet processing machine including: holding means for holding a platelike workpiece on which a first predetermined cutting line and a second predetermined cutting line intersecting the first predetermined cutting line are set; processing water supplying means for supplying high-pressure processing water; a nozzle adapted to emit the processing water supplied from the processing water supply means, to the workpiece held by the holding means; and emission-position moving means for relatively moving the nozzle and the holding means to change a position where the processing water is emitted from the nozzle to the workpiece; wherein while the nozzle and the holding means are relatively moved by the emission-position moving means, the processing water emitted from the nozzle is directed to the workpiece held by the holding means along the first predetermined cutting line and along the second predetermined cutting line to cut the first and second predetermined cutting lines, the water jet processing method comprising: a first cutting step for cutting the first predetermined cutting line to form a first cut line at a relative travel speed between the nozzle and the holding means set to a first speed; and a second cutting step for cutting the second predetermined cutting line to form a second cut line, the second predetermined cutting line being cut in a section anteroposterior to an intersection between the first cut line and the second predetermined cutting line at the relative travel speed set to a second speed lower than the first speed.