Laser processing machine and laser processing method
A laser processing machine includes a coupler that is an optical device capable of changing a beam profile of a laser beam emitted from a fiber laser oscillator, a focusing lens configured to focus the laser beam emitted from the coupler, the focusing lens including a first lens region with a first focal length on an inner peripheral side thereof and a second lens region with a second focal length on an outer peripheral side thereof, the second focal length being different from the first focal length, and a moving mechanism configured to move the focusing lens in an optical axis direction.
1 . A laser processing machine comprising:
a coupler capable of changing a spreading angle and a beam diameter of a laser beam emitted from a fiber laser oscillator;
a collimator lens configured to receive the laser beam emitted from the coupler and convert the laser beam into a collimated beam;
a focusing lens configured to focus the collimated laser beam emitted from the collimator lens, the focusing lens including a first lens region with a first focal length on an inner peripheral side of the focusing lens and a second lens region with a second focal length on an outer peripheral side of the focusing lens, the second focal length being longer than the first focal length; and
a moving mechanism configured to move the focusing lens in an optical axis direction,
wherein a focusing position of the first lens region of the focusing lens is on an optical axis of the laser beam, and a focusing position of the second lens region is at a ring-shaped position around the optical axis, and
wherein, by changing the spreading angle and the beam diameter of the laser beam by the coupler, the laser beam is selectively made incident on only the first lens region, only the second lens region, or both the first lens region and the second lens region of the focusing lens, thereby changing a beam profile of the laser beam irradiated on an object to be processed.
2 . The laser processing machine according to claim 1 , wherein a focusing position of the first lens region of the focusing lens is on an optical axis of the laser beam, and a focusing position of the second lens region is at a position deviated from the optical axis.
3 . The laser processing machine according to claim 1 , wherein the coupler changes a beam parameter product of the laser beam emitted from the fiber laser oscillator to change the spreading angle and the beam diameter.
4 . A laser processing method carried out by the laser processing machine according to claim 1 , the laser processing method comprising
moving, by the moving mechanism, the focusing lens in the optical axis direction so that a length between the focusing lens and an object to be processed is between the first focal length and the second focal length when the laser beam is made incident on the first lens region and the second lens region of the focusing lens by the coupler.
5 . A laser processing method carried out by the laser processing machine according to claim 1 , the laser processing method comprising
moving, by the moving mechanism, the focusing lens in the optical axis direction so that a length between the focusing lens and an object to be processed is the second focal length when a ring-shaped laser beam is made incident on the second lens region of the focusing lens by the coupler.