摘要 |
Polycrystalline alumina tubing is scribed by means of laser pulses which are reiteratively focused on the same spots at spaced time intervals. By drilling small holes, the laser need be on for a very short period of time only, and only the surface layers are vaporized, thereby minimizing heat shock. The holes are deepened by repeating the series of pulses and directing them sequentially into the same holes. For tubing, an encoder is used which senses the angular position of the tubing as it is rotated and causes the laser to deliver pulses at the same angles at every revolution. When the holes have been sufficiently deepened, the tubing is snapped and breaks clean in the plane of the holes. |