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US 4,947,023 AGranted
Method and apparatus for roll dulling by pulse laser beam
AssigneeNippon Steel Corporation
InventorsKatsuhiro Minamida, Junya Suehiro
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AssigneeNippon Steel Corporation
InventorsKatsuhiro Minamida, Junya Suehiro
Estimating the term…
When the power output of a continuous wave oscillated laser is changed to a pulsed laser by Q-switching, in the conventional method of Q-switching, if the pulse repetition rate is changed, the condition of oscillated excitation is changed and the pulse waveform or pulse peak power are simultaneously changed; and therefore, a stable dulling process is impracticable. The present invention decreases the cavity loss of a laser oscillator during a pulse off by decreasing power output of the radio-frequency signal applied to the Q-switch, and consequently, controls the pulse waveform to that required for the roll dulling process. In accordance with the method of the invention, the roughness of the dulled roll surface consists of innumerable small craters and is suitable for a high speed fine dulling process.
A method for roll-dulling by a pulse laser, in which a continuous wave solid state laser is changed to a pulsed laser by Q-switching, and the roll surface is dulled by said pulsed laser, said method being characterized in that when said pulse laser power is output the cavity loss of a laser oscillator during a pulse off is decreased in accordance with a drop in a power output of a radio-frequency signal applied to a Q-switch and a surplus accumulation of excited molecules in the laser resonator is controlled, and as a result, irregularity of the pulse waveform is decreased, and said pulse peak value and the half-power width of the pulse waveform is controlled to full width of half maximum that required for roll-dulling process.
A method as claimed in claim 5, characterized in that a each beam diameter of the plurality of laser beams is enlarged by the beam expander and said laser beams are combined into a laser beam group made parallel or nonparallel.
An apparatus for roll-dulling by a pulsed laser, in which the Q-switch controller comprises a pulse oscillator for determining a pulse repetition rate and the output power of a radio-frequency signal and a one-shot multi vibrator for determining the pulse interval, and the laser oscillator comprises a radio-frequency signal source to which a power output exchange signal is applied by the Q-switch controller and the Q-switching is effected upon output of the signal to said radio-frequency source.
A method for roll-dulling by a pulse laser, in which a continuous wave solid state laser is changed to a pulsed laser by Q-switching, and the roll surface is dulled by said pulsed laser, said method being characterized in that when said pulse laser power is output the cavity loss of a laser oscillator during a pulse off is decreased and a surplus accumulation of excited molecules in the laser resonator is controlled, and as a result, irregularity of the pulse waveform is decreased, and said pulse peak value and the half-power width of the pulse waveform is controlled to full width of half maximum that required for roll-dulling process,
Dependencies are inferred from the claim text.