Laser machining device and laser oscillation control method

A laser oscillation control method mounted on a fiber laser machining device, for controlling an operation of a laser oscillator capable of oscillating a laser beam to have a variable output according to a machining condition, the laser oscillation control method comprising:

• detecting, by a sensor, an intensity of leakage light leaking from a cladding side face of an optical fiber through which said laser beam is propagating, and obtaining a detection signal indicating said intensity,
• obtaining said intensity or an amount of light from said detection signal, and comparing said intensity or said amount of light obtained, with a light value threshold that is set in advance, and
• controlling an operation of said laser oscillator according to a result of said comparing, by a laser oscillation control device that includes a CPU and a memory and further comprises the sensor, a control unit and a monitor unit, the monitor unit being configured to receive a detecting signal outputted by the sensor and to carry out signal exchanges with the control unit, the fiber laser machining device comprising an output display and/or speech unit configured to output information from the control unit externally, and an input unit configured for a user to input information to the control unit,
• wherein said light value threshold is set to be a different value according to each of a plurality of outputs of said laser oscillator,
• said comparing compares, by the CPU, said light value threshold according to a laser beam output that is being oscillated by said laser oscillator, with said intensity or said amount of light, and
• said controlling stops a laser oscillation of said laser oscillator, increases the output of said laser beam oscillated by said laser oscillator, or decelerates a relative moving speed of a work on which said laser beam is irradiated, when said intensity or said amount of light exceeds a light value threshold, based on a result of said comparing,
• wherein the light value threshold is set based upon a predetermined reference level.

A laser machining device, comprising:

• a laser oscillator for oscillating a laser beam to have a variable output according to a machining condition;
• an optical fiber for propagating said laser beam;
• a sensor for detecting an intensity of light leaking from a cladding side face of said optical fiber and outputting a detection signal indicating said intensity;
• and
• a laser oscillation control device for controlling an operation of said laser machining device based on said detection signal,
• the laser oscillation control device comprising a CPU and a memory and further comprising:
• a control unit,
• said sensor, and
• a monitor unit configured to receive the detection signal outputted by the sensor and to carry out signal exchanges with the control unit,
• an output unit configured to output information from the control unit externally,
• an input unit configured for a user to input information to the control unit,
• wherein said CPU compares a first light value threshold that is set according to a laser beam output with said intensity or an amount of light obtained from said detection signal, when an output of said laser oscillator is less than or equal to a prescribed output, and
• compares a second light value threshold that is set according to the laser beam output with said intensity or an amount of light obtained from said detection signal, when an output of said laser oscillator is greater than said prescribed output,
• sets another light value threshold for said intensity, divides a waveform of said laser beam for each prescribed unit time, and obtains a number of divided portions that exceed said another light value threshold, and
• controls the operation of said laser machining device based on a result of said comparing and said number of divided portions.

A laser oscillation control method mounted on a fiber laser machining device, for controlling an operation of a laser oscillator capable of oscillating a laser beam to have a variable output according to a machining condition, the laser oscillation control method comprising:

• detecting, by a sensor, an intensity of leakage light leaking from a cladding side face of an optical fiber through which said laser beam is propagating and obtaining a detection signal indicating said intensity;
• and
• obtaining said intensity or an amount of light from said detection signal, and comparing said intensity or said amount of light obtained, with a light value threshold that is set in advance;
• and
• controlling an operation of said laser oscillator according to a result of said comparing, by a laser oscillation control device that includes a CPU and a memory and further comprises the sensor, a control unit and a monitor unit, the monitor unit being configured to receive the detecting signal outputted by the sensor and to carry out signal exchanges with the control unit, the fiber laser machining device comprising an output unit configured to output information from the control unit externally, and an input unit configured for a user to input information to the control unit,
• wherein said light value threshold is set to be a different value according to each of a plurality of outputs of said laser oscillator,
• said comparing, by the CPU, compares said light value threshold according to a laser beam output that is being oscillated by said laser oscillator, with said intensity or said amount of light, and
• said controlling stops a laser oscillation of said laser oscillator, increases the variable output of said laser beam oscillated by said laser oscillator, or decelerates a relative moving speed of a work on which said laser beam is irradiated, when said intensity or said amount of light exceeds said light value threshold based on a result of said comparing,
• setting another light value threshold for the intensity, dividing a waveform of said laser beam for each prescribed unit time, and obtaining a number of divided portions that exceed said another light value threshold;
• and
• controlling an operation of said fiber laser machining device based on a result of said comparing and said number of divided portions.