Abstract: In a water jet processing method, when a nozzle adapted to emit water jet is moved relatively to a substrate to form a second cut line intersecting a first cut line, the relative travel speed of the nozzle is set to a second speed lower than a first normal speed by about 1/5 to 1/20 at least in a section anteroposterior to the intersection. Delay-inclination of a front edge of the second cut line is eliminated as much as possible to thereby prevent the occurrence of an insufficient processing area.

Abstract: In a water jet processing method, when a nozzle adapted to emit water jet is moved relatively to a substrate to form a second cut line intersecting a first cut line, the relative travel speed of the nozzle is set to a second speed lower than a first normal speed by about ? to 1/20 at least in a section anteroposterior to the intersection. Delay-inclination of a front edge of the second cut line is eliminated as much as possible to thereby prevent the occurrence of an insufficient processing area.

Abstract: A package base is held on a holding table, and an XYZ moving mechanism is next moved to adjust a jet position to a cutting start point of a primary subject line to be first cut. Thereafter, a cutting water supplying unit is operated to direct a water jet onto the package base at this cutting start point. Thereafter, the XYZ moving mechanism is operated to move the package base, thereby cutting the package base along the primary subject line until a cutting stop point. Similarly, this cutting operation is repeated for the other primary subject line to thereby obtain a plurality of primary cut areas having the same shape and size in the condition that each primary cut area is integrally supported at its opposite ends to the package base, thus finishing a primary cutting step. Thereafter, a dicing tape is attached to one side surface of the package base. Thereafter, the package base is cut along a plurality of secondary subject lines as in the primary cutting step, thus finishing a secondary cutting step.

Abstract: To provide an abrasive water jet cutting machine in which an abrasive recovery unit can be continuously used without needing maintenance, and an abrasive having a uniform grain size can be easily recovered, the machine has a catch tank for receiving a high-pressure abrasive mixture liquid jetted from a jet nozzle, and an abrasive recovery unit that recovers abrasive having a grain size in a reusable predetermined range from the abrasive mixture liquid transported from the catch tank, and transports abrasive mixture liquid including recovered abrasive into an abrasive-mixture-liquid retention tank; wherein the abrasive recovery unit has an abrasive sorting tank which flows the abrasive mixture liquid transported from the catch tank in an approximately horizontal direction, and sorts abrasive depending on grain size by using difference in sedimentation rate depending on grain size, and recovers the abrasive having the grain size in the reusable predetermined range.