This paper concerns the laser drilling in percussion regime. Direct observation of the rear surface during the breakthrough is performed with high-speed camera. The breakthrough duration increases as function of time from 100 to 280 µs for laser power from 3 KW to 18 KW. For any incident laser power, breakthrough velocity is rather constant at 1.5 m/s. The assistant gas plays role in pushing liquid and vapor from the rear surface. The diameter is larger with assistant gas. Laser transmitted by the rear hole is measured. It is long and intense enough to damage surface located near the rear hole.
Topics
Laser drill
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