Abstract: An information projecting method projects information concerning a cut piece onto the cut piece, which is cut and separated from a plate-like work and is on a placement table, or onto a position adjacent to the cut piece. To adjust to an aspect ratio of a projector, the method assigns a long side of the work to an X-axis direction of the aspect ratio and a short side of the work to a Y-axis direction of the aspect ratio, finds a positional relationship d between a top face of the work and the projector according to plate thickness information of the work on the placement table and positioned corresponding to the projector arranged at a predetermined Y-axis-direction position, and with a zoom ratio based on the found positional relationship, projects the information concerning the cut piece onto the cut piece or onto a position adjacent to the cut piece.

Abstract: A laser guided discharge machining apparatus includes a vacuum chamber able to accommodate a workpiece and in which it is possible to create a reduced pressure condition of 3000 Pa or below, a discharge electrode accommodated in the vacuum chamber able to discharge charged particles, a laser that emits a laser beam toward the vacuum chamber, a laser guidance apparatus for guiding the laser beam to irradiate a part of the workpiece in the vacuum chamber, and a discharge delay measurement apparatus for detecting a time delay between a time at which laser irradiation is triggered and a time at which discharge takes place from the discharge electrode.