WO2020241783A1

WO2020241783A1 - Variation cause identifying method and laser processing apparatus

Info

Publication number: WO2020241783A1
Application number: PCT/JP2020/021201
Authority: WO
Inventors: 学西原; 憲三柴田; 静波王; 西尾　正敏
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2019-05-30
Filing date: 2020-05-28
Publication date: 2020-12-03
Also published as: JP7113320B2; CN113874151A; CN113874151B; JPWO2020241783A1

Abstract

A control unit is caused to: perform a current control execution step in which drive current feedback control is performed so as to bring a laser output of laser light of a laser oscillator closer to a target value; identify a variation occurrence timing at which, during execution of the current control execution step, an output variation occurred such that a difference between the laser output and the target value exceeds a predetermined threshold value; identify, from a plurality of first physical quantities measured during execution of the current control execution step, an abnormal physical quantity exhibiting an abnormal value within a first monitoring time determined in accordance with the variation occurrence timing; identify, from a plurality of second physical quantities providing a cause for variation of the abnormal physical quantity, a physical quantity exhibiting an abnormal value within a second monitoring time determined in accordance with an abnormality start timing at which the abnormal physical quantity exhibited an abnormal value, as a variation cause; and output information indicating the identified variation cause to an output device.

Description

Fluctuation factor identification method and laser processing equipment

The present disclosure relates to a method for identifying a variable factor for specifying a variable factor for the laser output of a laser oscillator and a laser processing apparatus.

Patent Document 1 describes a laser oscillator, an output measuring unit that measures the laser output of the laser light emitted by the laser oscillator, and a measured value of the output measuring unit in order to bring the laser output closer to a target value. A laser processing apparatus including a control unit for controlling an operation signal of a laser oscillator is disclosed.

Japanese Unexamined Patent Publication No. 2003-53564

By the way, when the laser processing apparatus is to perform feedback control as in Patent Document 1, the difference between the laser output and the target value is large between the measurement by the output measuring unit and the reflection of the measured value in the laser output. Output fluctuation may occur. Since such output fluctuation causes a decrease in processing accuracy, there is a demand that the apparatus or the user wants to easily take measures to prevent such output fluctuation.

The present disclosure has been made in view of this point, and the purpose of the present disclosure is to facilitate the device or the user to take measures to prevent the output fluctuation of the laser oscillator.

In order to achieve the above object, the present disclosure includes a laser oscillator, an output measuring unit for measuring the amount of laser light emitted by the laser oscillator, and the laser output of the laser beam so as to approach a target value. A variable factor identification process executed by the control unit in a laser processing apparatus including a control unit that performs feedback control of a drive current supplied to the laser oscillator based on a measured value of the output measurement unit. Based on the current control execution process in which the control unit performs the feedback control and the measured value of the output measurement unit, the difference between the laser output and the target value exceeds a predetermined threshold value during the execution of the current control process. The fluctuation generation specified in the timing specification processing is performed from the timing specification process for specifying the fluctuation occurrence timing in which the output fluctuation occurs and the plurality of first physical quantities measured by the laser processing apparatus during the execution of the current control execution step. From the abnormal physical quantity identification process that identifies the abnormal physical quantity that becomes an abnormal value within the first monitoring time determined according to the timing, and the plurality of second physical quantities that cause fluctuations in the abnormal physical quantity specified in the abnormal physical quantity identification process. The variable factor identification process that specifies the physical quantity that becomes an abnormal value as a variable factor within the second monitoring time that is determined according to the abnormal start timing when the abnormal physical quantity becomes an abnormal value, and the variable factor that is specified in the variable factor identification process. It is characterized in that it executes a variable factor output process that outputs information indicating the above to an output device.

As a result, when the abnormal physical quantity becomes an abnormal value due to the fluctuation factor becoming an abnormal value and the output fluctuation occurs due to the abnormal physical quantity becoming an abnormal value, the device or the user can output the device. The variable factor can be recognized by referring to the information output by. Therefore, it becomes easier for the device or the user to take measures to prevent output fluctuations.

According to the present disclosure, it becomes easy for the device or the user to take measures to prevent output fluctuations.

It is a schematic diagram which shows the structure of the laser processing apparatus which concerns on Embodiment 1 of this disclosure. It is a schematic diagram which shows the structure of the laser apparatus which concerns on Embodiment 1 of this disclosure. It is a schematic diagram which shows the structure of a plurality of laser modules. It is a side view of a laser module. It is a front view of a laser module. It is a flowchart which shows the operation of a control part. It is a graph which shows the target value, the measured value, the output before correction, and the correction amount of a laser output during execution of a processing program. It is a graph which shows the measured value of the temperature of a laser apparatus during execution of a machining program. It is a graph which shows the measured value of the humidity of a laser apparatus during execution of a processing program. It is a graph which shows the pressure of the circulating fluid during execution of a processing program.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description of preferred embodiments is merely exemplary and is not intended to limit the disclosure, its applications or its uses.

As shown in FIG. 1, the laser processing device 100 according to the present embodiment includes a laser oscillator 10, a laser light emitting head 40, a transmission fiber 50, a control unit 60, a power supply 70, and a display device as an output device. It includes 80, a controller 90, a chiller 14, and a dehumidifying device 15. The laser oscillator 10 and the end portion (incident end) of the transmission fiber 50 on the condensing unit 13 side are housed in the housing 11.

The laser oscillator 10 has a plurality of laser devices 20, a beam coupler 12, and a condensing unit 13.

As shown in FIG. 2, the laser device 20 combines, for example, 10 laser modules 30 that emit laser light LB1 having different wavelengths from each other and laser light LB1 emitted from each of the 10 laser modules 30 to emit the laser light LB1. The diffraction grating 22, the partially transmitted mirror 23 that transmits a part of the laser light emitted by the diffraction grating 22 as the laser light LB2, and reflects the rest as the reflected light LB3, and the reflected light LB3 from the partially transmitted mirror 23. It has a photodiode 24 that receives light and measures the amount of reflected light LB3, a temperature measuring unit 20a that measures the temperature inside the laser device 20, and a humidity measuring unit 20b that measures the humidity inside the laser device 20. ..

As shown in FIGS. 3 to 5, each laser module 30 has a laser diode bar (LD bar) 31, and the laser diode bar 31 is a semiconductor laser array having a plurality of emitters 31b arranged in parallel. is there. In other words, the laser diode bar 31 is a semiconductor laser array composed of a plurality of laser diodes arranged in parallel having an emitter 31b. The laser diode bar 31 has a flat plate shape having a rectangular shape in a plan view, and a plate-shaped positive electrode 32 is arranged on one surface thereof, and one surface of the positive electrode 32 is attached. Further, a plate-shaped negative electrode 33 wider than the positive electrode 32 is arranged on the other surface of the laser diode bar 31, and a part of one surface of the negative electrode 33 is attached. One side surface of the laser diode bar 31 constitutes a laser light emitting surface 31a that emits the laser light LB1. A wiring 35 is connected to each electrode (positive electrode 32, negative electrode 33), and a current (electric power) is supplied from a power source 70 described later via the wiring 35. The number of emitters 31b included in one laser diode bar 31 is set to, for example, 50. The laser diode bars 31 of the 10 laser modules 30 are connected in series with each other.

A thermocouple 36 for measuring the temperature in the vicinity of the laser diode bar 31 is attached to the region where the laser diode bar 31 is not attached on the attachment surface of the laser diode bar 31 of the negative electrode 33. As a means for measuring the temperature in the vicinity of the laser diode bar 31, the thermocouple 36 may be replaced with another means such as an RTD (Resistance Temperature Detector), a thermistor, or an IC (Integrated Circuit) sensor. Good. Further, a semiconductor device such as a thermistor or an IC sensor may be integrally formed with the laser diode bar 31, whereby the internal temperature of the laser diode bar 31 can be indirectly or directly measured and measured. The temperature can be brought closer to the internal temperature of the laser diode bar 31.

The beam coupler 12 combines the laser light LB2 (see FIG. 2) emitted from each of the plurality of laser devices 20 with one laser light LB4 and emits the laser light LB4 to the condensing unit 13. The beam coupler 12 includes a photodiode 12a that measures a part of the amount of light that occupies a certain proportion of the laser beam LB4, a temperature measuring unit 12b that measures the temperature inside the beam coupler 12, and the humidity inside the beam coupler 12. A humidity measuring unit 12c for measuring the temperature is provided.

The condensing unit 13 condenses the incident laser light LB4 by a condensing lens (not shown) arranged inside, reduces the beam diameter by a predetermined magnification, and emits it to the transmission fiber 50. In FIG. 2, reference numeral LB5 is a laser beam emitted by the condensing unit 13. The light collecting unit 13 has a connector (not shown), and the incident end of the transmission fiber 50 is connected to the connector. The condensing unit 13 includes a photodiode 13a that measures a part of the amount of light that occupies a certain proportion of the laser beam LB5, a temperature measuring unit 13b that measures the temperature inside the condensing unit 13, and humidity inside the condensing unit 13. A humidity measuring unit 13c for measuring the light is provided.

By configuring the laser oscillator 10 in such a configuration, it is possible to obtain a high-power laser beam LB5 having a laser output exceeding several kW.

The transmission fiber 50 guides the laser light LB5 emitted by the laser oscillator 10 and incident on the incident end of the transmission fiber 50 to the laser light emitting head 40.

The laser light emitting head 40 irradiates the laser light LB6 guided by the transmission fiber 50 toward the outside. For example, in the laser machining apparatus 100 shown in FIG. 1, the laser beam LB6 is emitted by the laser beam emitting head 40 toward the work W, which is a machining object arranged at a predetermined position. By doing so, the work W is laser machined. The laser light emitting head 40 is provided with a photodiode 40a as an output measuring unit for measuring a part of the amount of light that occupies a certain ratio of the laser light LB6.

The control unit 60 performs feedback control of the drive current supplied to the laser oscillator 10 based on the measured value of the photodiode 40a so that the laser output of the laser beam LB6 approaches a predetermined target value. Here, the control of the drive current by the control unit 60 is performed by outputting a command voltage value to the power supply 70. Further, the control unit 60 stores a machining program to be executed when performing a predetermined machining on the work W. The machining program defines a target value of the laser output of the laser beam LB6 at each timing during machining. Details of the control by the control unit 60 will be described later.

The power supply 70 supplies a drive current to each of the plurality of laser devices 20 based on the command voltage value output by the control unit 60.

The display device 80 outputs and displays information indicating an abnormal physical quantity described later and information indicating a fluctuation factor described later under the control of the control unit 60.

The controller 90 receives an input from the user for starting the machining program execution, and outputs a command for instructing the start of the machining program execution to the control unit 60.

The chiller 14 inputs a chiller main body 14a that controls the temperature of each laser device 20 of the laser oscillator 10 and an input for controlling the operation of the chiller main body 14a by circulating the circulating liquid through the plurality of laser devices 20. It is provided with a chiller operation unit 14b that receives and outputs a command corresponding to the input to the chiller main unit 14a. The circulating liquid circulates inside each laser device 20 and in a pipe 16 arranged between the laser device 20 and the chiller main body 14a. The pipes 16 corresponding to each laser device 20 are connected in parallel.

The dehumidifying device 15 receives an input for controlling the operation of the dehumidifying device main body 15a that supplies dry air to each laser device 20 of the laser oscillator 10 to dehumidify, and the dehumidifying device main body 15a, and commands in response to the input. Is provided with a dehumidifying operation unit 15b that outputs the dehumidifying device main body 15a. The dry air is introduced into each laser oscillator 10 via the introduction pipe 17 and is led out through the outlet pipe 18. In the present embodiment, the introduction tube 17 and the lead-out tube 18 are arranged so as to connect the laser oscillator 10 in parallel, but the laser oscillator 10 may be arranged so as to be connected in series.

Hereinafter, the operation in which the control unit 60 controls the drive current will be described with reference to FIG.

First, in S101, the control unit 60 measures the photodiode 40a so that the laser output of the laser beam LB6 approaches the target value of each timing set in the machining program by executing the stored machining program. Feedback control of the command voltage value is performed based on the value. That is, feedback control of the drive current supplied to the laser device 20 is performed (current control execution step). The control unit 60 stores the measured values of the

photodiodes

12a, 13a, 24, 40a, the

temperature measuring units

12b, 13b, 20a, the thermocouple 36, and the

humidity measuring units

12c, 13c, 20b during the execution of the machining program as a data log. To do. FIG. 7A shows when the target value of the laser output of the laser beam LB6 during the execution of the machining program in S101, the measured value of the laser output of the laser beam LB6 during the execution of the machining program in S101, and the command voltage value are constant. The laser output of the laser beam LB6 (output before correction) and the measured value of the laser output of the laser beam LB6 during execution of the machining program in S101 and the laser output of the laser beam LB6 when the command voltage value is constant. Indicates the difference (correction amount). FIG. 7B shows the measured value of the temperature of the laser apparatus 20 during the execution of the machining program in S101, and FIG. 7C shows the measured value of the humidity of the laser apparatus 20 during the execution of the machining program in S101. FIG. 7D. Indicates the pressure of the circulating fluid circulated by the chiller-14 during execution of the machining program in S101. Here, the measured value of the laser output of the laser beam LB6 is calculated by the control unit 60 based on the measured value of the photodiode 40a.

Next, in S102, the control unit 60 measures the laser output of the laser beam LB6 during execution of the machining program in S101 based on the measured value of the photodiode 40a by referring to the data log stored in S101. The fluctuation occurrence timing t1 (see FIGS. 7A to 7D) in which the output fluctuation in which the difference between the value and the target value specified by the machining program exceeds a predetermined threshold TH is specified and stored (timing specifying step). .. At this time, the laser output of the laser beam LB6 does not stop.

Next, in S103, the control unit 60 receives a plurality of first physical quantities measured by the laser machining apparatus 100 during execution of the machining program in S101 within the first monitoring time T1 determined according to the fluctuation occurrence timing t1. Identify the abnormal physical quantity that becomes an abnormal value (abnormal physical quantity identification step). At this time, the laser output of the laser beam LB6 does not stop. As a result, it is possible to prevent the occurrence of construction defects due to the stoppage of the laser output. The plurality of first physical quantities include the measured values of the

temperature measuring units

12b, 13b, 20a, the thermocouple 36, and the

humidity measuring units

12c, 13c, 20b. The first monitoring time T1 is set to the time from the timing before the predetermined time of the fluctuation occurrence timing t1 to the timing after the predetermined time of the fluctuation occurrence timing t1. Then, the control unit 60 outputs and displays the information indicating the abnormal physical quantity on the display device 80. As a result, the user can recognize the abnormal physical quantity as a physical quantity that is likely to be a factor of output fluctuation. Further, the control unit 60 identifies and stores the abnormality start timing t2 in which the abnormal physical quantity becomes an abnormal value during the execution of the machining program in S101. For example, the measured value of the temperature measuring unit 20a is regarded as an abnormal value when it does not fall within the numerical range of 0 to H1 ° C. in the first monitoring time T1. In the examples of FIGS. 7A to 7D, the measured value of the temperature measuring unit 20a rises in synchronization with the decrease of the measured value of the laser output of the laser beam LB6, and the temperature measuring unit 20a increases the measured value within the first monitoring time T1. Since the measured temperature exceeds H1 ° C., the temperature is specified as an abnormal physical quantity. As a result, the user recognizes the temperature of the laser device 20 (laser diode bar 31) as a physical quantity that is likely to be a factor of output reduction, and lowers the temperature of the circulating fluid with respect to the chiller operation unit 14b of the chiller 14. Can be input. Further, the measured value of the humidity measuring unit 20b is regarded as an abnormal value when it does not fall within the predetermined numerical range Ra within the first monitoring time T1. In the examples of FIGS. 7A to 7D, the humidity measured by the humidity measuring unit 20b is within the predetermined numerical range Ra within the first monitoring time T1, and is therefore considered not to be an abnormal physical quantity.

Next, in S104, the control unit 60 is within the second monitoring time T2 determined according to the abnormality start timing t2 specified in S103 from the plurality of second physical quantities that cause fluctuations in the abnormal physical quantity specified in S103. The physical quantity that becomes an abnormal value is specified as a variable factor (variable factor identification step). At this time, the laser output of the laser beam LB6 does not stop. As a result, it is possible to prevent the occurrence of construction defects due to the stoppage of the laser output. The second monitoring time T2 is set to the time from the timing before the predetermined time of the abnormal start timing t2 to the timing after the predetermined time of the abnormal start timing t2. Specifically, when the abnormal physical quantity specified in S103 is the temperature measured by the temperature measuring unit 20a, a plurality including the pressure, flow rate, and temperature (cooling water temperature) of the circulating liquid circulated by the chiller 14. The fluctuation factor is specified from the second physical quantity of. The pressure of the circulating fluid circulated by the chiller 14 is considered to be an outlier if it does not fall within the numerical range of H2 to H3Pa. In the examples of FIGS. 7A to 7D, the pressure of the circulating fluid circulated by the chiller 14 is lower than H2Pa within the second monitoring time T2, so that the pressure of the circulating fluid is specified as a variable factor. Further, when the abnormal physical quantity specified in S103 is the humidity measured by the humidity measuring unit 20b, a plurality including the temperature measured by the temperature measuring unit 20a and the pressure of the dry air supplied by the dehumidifying device 15. From the second physical quantity of, the variable factor is specified.

Next, in S105, the control unit 60 outputs and displays the information indicating the fluctuation factor specified in S104 on the display device 80 (variation factor output step). At this time, the laser output of the laser beam LB6 does not stop. As a result, it is possible to prevent the occurrence of construction defects due to the stoppage of the laser output. By the output display, the user can recognize the fluctuation factor by referring to the information output and displayed on the display device 80, and it becomes easy to take measures to prevent the output fluctuation. For example, when the fluctuation factor is a physical quantity of any one of the pressure, the flow rate, and the temperature of the circulating fluid circulated by the chiller 14, the user uses the chiller operation unit 14b of the chiller 14 so as to suppress the output fluctuation. , You can perform input operations to control physical quantities that cause fluctuations. Further, when the fluctuation factor is the pressure of the dry air supplied by the dehumidifying device 15, the user controls the pressure of the dry air to the dehumidifying operation unit 15b of the dehumidifying device 15 so as to suppress the output fluctuation. Can be done.

In the above embodiment, the laser oscillator 10 is provided with a plurality of laser devices 20, but only one may be provided. In such a case, the laser beam LB2 output from the laser device 20 is directly incident on the transmission fiber 50.

Further, in the above embodiment, the number of laser modules 30 and laser diode bars 31 included in one laser device 20 is set to 10, but the maximum output required for the laser device 20 and the price of the laser device 20 are determined. Other numbers may be set depending on the number.

Further, in the above embodiment, the number of emitters 31b included in one laser diode bar 31 is set to 50, but other emitters 31b are required depending on the maximum output required for the laser module 30, the price of the laser diode bar 31, and the like. It may be set to the number.

Further, in the above embodiment, the abnormal physical quantity is specified from the measured values of the

temperature measuring units

12b, 13b, 20a, the thermocouple 36, and the

humidity measuring units

12c, 13c, 20b, but the voltage value of each part in the laser processing apparatus 100, The abnormal physical quantity may be specified from the current value and the loss amount of the laser light in each part in the laser processing apparatus 100 obtained based on the measured values of the

photodiodes

12a, 13a, 24, and 40a.

Further, in the above embodiment, in S103, the condition that the control unit 60 considers that the temperature in the first monitoring time T1 is an abnormal value is that the temperature does not fall within a predetermined numerical range. Other conditions may be used, such as the temperature gradient not falling within a predetermined numerical range.

Further, in the above embodiment, in S104, the condition that the control unit 60 considers the pressure of the circulating fluid to be an abnormal value within the second monitoring time T2 is that the pressure does not fall within a predetermined numerical range. However, other conditions may be used, such as the slope of the pressure not falling within a predetermined numerical range.

Further, in the above embodiment, the output device is a display device 80 that displays information indicating the fluctuation factor, but it may be a device that outputs information indicating the fluctuation factor as a signal to another device. Then, another device may recognize the fluctuation factor and take measures to prevent the output fluctuation.

Further, in the above embodiment, when the abnormal physical quantity is the humidity measured by the humidity measuring unit 20b, the temperature measured by the temperature measuring unit 20a and the dehumidifying device are applied to a plurality of second physical quantities to be specified as fluctuation factors. Both of the pressures of the dry air supplied by 15 are included, but only one of them may be included.

Further, in the above embodiment, when the abnormal physical quantity is the temperature measured by the temperature measuring unit 20a, the pressure, the flow rate, and the flow rate of the circulating liquid circulated by the chiller 14 to the plurality of second physical quantities to be specified as the fluctuation factors. All physical quantities of temperature are included, but only one or two physical quantities may be included. The second physical quantity includes not only the physical quantity related to the laser oscillator 10 but also the physical quantity related to the peripheral device (for example, the chiller 14) outside the laser oscillator 10, so that not only the laser oscillator 10 but also the peripheral device can be maintained. Can be prompted.

The variable factor identification method and the laser processing apparatus of the present disclosure can make it easy for the apparatus or the user to take measures to prevent the output fluctuation, and are useful for identifying the fluctuation factor of the laser output of the laser oscillator.

100 Laser Machining Equipment 10 Laser Oscillator 14 Chiller 15 Dehumidifier 40a Photodiode (Output Measuring Unit)
60 Control unit 80 Display device (output device)
T1 1st monitoring time T2 2nd monitoring time TH threshold value t1 Fluctuation occurrence timing t2 Abnormal start timing

Claims

Laser oscillator and
An output measuring unit that measures the amount of laser light emitted by the laser oscillator,
In a laser processing apparatus provided with a control unit that performs feedback control of a drive current supplied to the laser oscillator based on a measured value of the output measuring unit so that the laser output of the laser light approaches a target value. A method of identifying variable factors executed by the control unit.
The current control execution step for performing the feedback control and
A timing specifying step for specifying a fluctuation occurrence timing in which an output fluctuation in which the difference between the laser output and the target value exceeds a predetermined threshold value occurs during execution of the current control execution step based on the measured value of the output measuring unit. When,
An abnormality that becomes an abnormal value within the first monitoring time determined according to the fluctuation occurrence timing specified in the timing specifying step from a plurality of first physical quantities measured in the laser processing apparatus during the execution of the current control execution step. Anomalous physical quantity identification step to identify physical quantity and
From a plurality of second physical quantities that cause fluctuations in the abnormal physical quantity specified in the abnormal physical quantity specifying step, the abnormal physical quantity becomes an abnormal value within the second monitoring time determined according to the abnormal start timing at which the abnormal physical quantity becomes an abnormal value. A variable factor identification step that identifies a physical quantity as a variable factor, and
A method for identifying a variable factor, which comprises executing a variable factor output step of causing an output device to output information indicating the variable factor specified in the variable factor specifying step.
In the method for identifying variable factors according to claim 1,
The laser processing apparatus further includes a chiller that controls the temperature of the laser oscillator by circulating a circulating liquid in the laser oscillator.
The plurality of first physical quantities include the temperature of the laser oscillator.
A method for identifying a variable factor, wherein the plurality of second physical quantities that cause the temperature fluctuation of the laser oscillator include at least one of the pressure, the flow rate, and the temperature of the circulating fluid.
In the method for identifying a variable factor according to claim 1 or 2.
The laser processing device further includes a dehumidifying device that supplies dry air to the laser oscillator to dehumidify the laser oscillator.
The plurality of first physical quantities include the humidity of the laser oscillator.
A method for identifying a variable factor, wherein the plurality of second physical quantities that cause fluctuations in the humidity of the laser oscillator include at least one of a temperature in the laser oscillator and a pressure of the dry air.
In the method for identifying a variable factor according to any one of claims 1 to 3,
A method for identifying a variable factor, characterized in that the timing specifying step, the abnormal physical quantity specifying step, and the variable factor specifying step are performed without stopping the laser output of the laser beam.
In the method for identifying a variable factor according to any one of claims 1 to 4,
A method for identifying a variable factor, wherein the second physical quantity includes not only a physical quantity related to the inside of the laser oscillator but also a physical quantity related to a peripheral device outside the laser oscillator.
Laser oscillator and
An output measuring unit that measures the amount of laser light emitted by the laser oscillator,
A laser processing apparatus including a control unit that performs feedback control of a drive current supplied to the laser oscillator based on the measured value of the output measuring unit so that the laser output of the laser beam approaches a target value. ,
The control unit includes a current control execution step that performs the feedback control, and
A timing specifying step for specifying a fluctuation occurrence timing in which an output fluctuation in which the difference between the laser output and the target value exceeds a predetermined threshold value occurs during execution of the current control execution step based on the measured value of the output measuring unit. When,
An abnormality that becomes an abnormal value within the first monitoring time determined according to the fluctuation occurrence timing specified in the timing specifying step from a plurality of first physical quantities measured in the laser processing apparatus during the execution of the current control execution step. Anomalous physical quantity identification step to identify physical quantity and
From a plurality of second physical quantities that cause fluctuations in the abnormal physical quantity specified in the abnormal physical quantity specifying step, the abnormal physical quantity becomes an abnormal value within the second monitoring time determined according to the abnormal start timing at which the abnormal physical quantity becomes an abnormal value. A variable factor identification step that identifies a physical quantity as a variable factor, and
A laser machining apparatus characterized in that it is configured to execute a variable factor output step of outputting information indicating a variable factor specified in the variable factor specifying step to an output device.