DEVICE AND METHOD FOR MACHINING DAM BAR

摘要

PCT No. PCT/JP95/02064 Sec. 371 Date May 14, 1996 Sec. 102(e) Date May 14, 1996 PCT Filed Oct. 9, 1995 PCT Pub. No. WO96/12300 PCT Pub. Date Apr. 25, 1996The array condition of leads (3) is detected by a photoelectric detector (41), the detection signal is subjected to signal processing to determine the timing to oscillate a pulsed laser beam, and a laser beam axis (13C) is relatively moved at a speed (v0) with a work table (21) while oscillating a pulsed laser beam (13A), thereby cutting a dam bar (5). At this time, the longitudinal size of a spot (13B) of the pulsed laser beam (13A) is adjusted to be twice or more the width of the dam bar (5) by a longitudinal beam transformer (11a), the transverse size of the spot 13B is adjusted to be not less than +E,fra 1/2+EE but not more than +E,fra 4/5+EE of the length of the dam bar (5) by a transverse beam transformer (11b), and a beam rotator (11c) is appropriately operated to make the longitudinal direction of the spot (13B) substantially aligned with the longitudinal direction of the lead (3) so that the spot (13B) lies across the width (W1) of the dam bar (5). As a result, the configuration after cutting the dam bar (5) becomes highly accurate and satisfactory.