Laser processing device having preprocessing controller and laser processing method

A laser processing device having a laser oscillator, a storage unit configured to store a processing program and processing conditions, and a controller configured to issue a command to perform laser processing in accordance with the processing program, the laser processing device being configured to perform laser processing by irradiating a workpiece with a laser beam, the laser processing device comprising:

• a light quantity measuring unit configured to measure the light quantity of light reflected or emitted from a processing point irradiated with a laser beam;
• a first storage unit configured to store high output conditions, which are previously found by an experiment or calculation in accordance with at least some of the processing conditions and which include the irradiation intensity and irradiation time, at which a workpiece is melted, changed in shape, or denatured;
• a second storage unit configured to store low output conditions, which are previously found by an experiment or calculation in accordance with at least some of the processing conditions and which include the irradiation intensity and irradiation time, at which a workpiece is not melted, changed in shape, or denatured;
• and
• a preprocessing controller which issues a command to perform preprocessing of a workpiece under the high output conditions, and a command to irradiate the workpiece with a laser beam under the low output conditions and which issues a command of whether to start the laser processing, based on a first light quantity measured by the light quantity measuring unit after the workpiece is irradiated with a laser beam under the low output conditions.