| 摘要 |
<p>PROBLEM TO BE SOLVED: To permit the forming of a through hole of a required configuration even when there is slight variability in the spatial distribution of laser energy by a method wherein the through hole is bored by projecting a laser beam from the inflow side of ink under the condition of masking and, subsequently, the laser beam is projected from the discharging side of the ink to spread the diameter of the hole. SOLUTION: A laser beam is projected from the inflow side of ink under the condition of masking through an optical member 3 to bore a convergent through hole. Subsequently, a work W is converted in front-and-rear direction and the laser beam is projected from the discharging side of ink under the condition of masking through the optical member 3 in the same manner to bore the through hole so as to obtain a final discharging side diameter by enlarging the diameter of the discharging hole to a diameter larger than the diameter of discharging side of the already bored through hole. Considering from the working characteristic of the laser beam, when viewed from the working direction of laser beam, the lengthwise directional configuration of the hole becomes a positive tapered shape and the taper angle of the hole is changed in accordance with the strength of laser energy.</p> |
