JP2009248157A - Laser beam machining method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance laser beam machining capability by improving a waveform modulation function in the waveform control of laser power. <P>SOLUTION: The laser beam machining apparatus includes a fiber laser oscillator 10, a laser power source 12, a laser incidence section 14, a fiber transmission system 15, a laser radiating section 16, a controller 18, a touch panel 20, etc. The controller 18 in terms of hardware is composed of a CPU (micro computer), an FPGA (field programmable gate array), a digital-analog (D/A) converter, an analog-digital (A/D) converter, etc. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser processing technique for performing desired laser processing by irradiating a workpiece with pulsed or continuous wave laser light, and in particular, a laser processing method and laser processing for controlling the waveform of laser beam output (power). Relates to the device.

  In general, a technique for controlling the waveform of the output of laser light in laser processing is often used in laser welding. For example, in laser spot welding, each welding point of a workpiece is irradiated with pulsed laser light in a single shot or in a continuous manner. Further, in laser seam welding, a pulsed laser beam is irradiated on a workpiece welding line with overlap scanning at a constant repetition frequency, or a continuous wave (CW) laser beam is irradiated with continuous scanning. In such laser welding processing, it is possible to adjust the degree of penetration, the degree of finish, etc. by arbitrarily changing the waveform of the laser power.

  For example, Patent Document 1 discloses a fiber laser processing in which a reference waveform is output from a control board (control unit), and a laser power source unit drives a laser excitation unit in response to this, and laser light having a desired waveform shape is oscillated and output. A machine is disclosed. Furthermore, this fiber laser processing machine discloses that the output of a processing laser beam is monitored and fed back to a laser power source unit.

  A conventional laser welding apparatus performs laser power waveform control by using a memory writing / reading function of a CPU (microcomputer). That is, when a user inputs a desired reference waveform through a man-machine interface such as a touch panel, the CPU encodes the set and input reference waveform at a predetermined sampling period and stores the binary code as reference waveform data. Write to. Then, when executing laser welding, the CPU reads the reference waveform data from the memory at time intervals of the sampling period, and reproduces the digital reference waveform signal. The digital reference waveform signal reproduced by the memory reading function of the CPU is converted into an analog reference waveform signal by the D / A converter, and the analog reference waveform signal is used as a control signal for the laser power supply unit. Typically, it is supplied to an output (power) of a processing laser beam oscillated and output from a laser oscillator, or to an excitation light source such as a laser diode (LD) for optically exciting an active medium in the optical resonator. Feedback control is applied so that the drive current or the like follows the analog reference waveform signal.

However, even if feedback control is applied in the waveform control of the laser power, the actual value of the monitoring target (laser output, LD drive current, etc.) does not always follow the reference waveform accurately. In the conventional laser welding apparatus, when checking whether the error of the waveform to be monitored with respect to the reference waveform is within a predetermined allowable range (good / bad determination), all necessary calculation processing is performed by the CPU. .
JP2007-190566

  However, the conventional technology that uses the CPU's memory write / read function and arithmetic processing function exclusively for the laser power waveform control as described above takes too much time for signal processing and meets the required specifications for today's precision welding processing. Insufficient response is a problem. Specifically, a long time is required for the bus cycle when the CPU reads the reference waveform data from the memory during reproduction of the reference waveform.

  Further, in order to more freely adjust the degree of welding penetration or the degree of finish in any welding process, modulation is also applied to the reference waveform. When such a waveform modulation function is installed, a calculation process for adding the modulation waveform data to the reference waveform data for one sample read from the memory is also performed, which further increases the load on the CPU. For this reason, a reference waveform with modulation is reproduced with a sampling period of 50 μsec or more at the shortest, and a high speed has been desired.

  In addition, since the conventional waveform modulation function can only provide waveform modulation that simply superimposes the rectangular waveform on the reference waveform, it has poor adaptability to various needs of laser processing.

  The present invention has been made in view of the above problems of the prior art, and provides a laser processing method and a laser processing apparatus that improve the laser processing capability by improving the waveform modulation function in the waveform control of the laser power. With the goal.

  In order to achieve the above object, a laser processing method of the present invention includes a first step of connecting a plurality of line segment waveform elements along a time axis to set a desired reference waveform, and at least one of the above-mentioned A second step of setting the contents of a predetermined item with respect to the modulation for the line segment waveform element, and parameter data including data representing the setting contents of the modulation item for the entire reference waveform or each of the line segment waveform elements And a predetermined calculation process based on the parameter data for each stage along the time axis to reproduce and conditionally modulate the line segment waveform element over the entire stage. A fourth step of substantially connecting the line segment waveform elements to restore the reference waveform; and outputting pulsed or continuous wave laser light used for desired laser processing. And a fifth step of varying in accordance with said recovered reference waveform.

  In the laser processing method of the present invention, the desired reference waveform is not decomposed at the setting stage along the time axis at the sampling period, but the reference waveform or each of the plurality of line segment waveform elements constituting the reference waveform is predetermined A plurality of parameter data indicating the attributes (modulation item contents, etc.) are generated, and information management of the parameter data for each stage is performed. And, when using the reference waveform for laser processing waveform control, along the time axis, reproduce the line segment waveform element by performing a predetermined calculation process based on the parameter data for each stage in order of the stage, Conditionally, this is modulated, and the line segment waveform elements are substantially connected over all stages to restore the reference waveform. Desired laser processing is performed by varying the output of pulsed or continuous wave laser light in accordance with the restored and modulated reference waveform.

  In a preferred aspect of the present invention, the modulation item includes an item for selecting whether or not to modulate each line segment waveform element, and the parameter data should be modulated for each line segment waveform element. Including flag data indicating whether or not. Then, in the fourth step, each line segment waveform element is conditionally modulated according to the flag. In this way, it is possible to conditionally modulate each line segment waveform element.

  In another preferred aspect, the modulation item includes an item for selecting whether or not to modulate the entire reference waveform, and the parameter data indicates whether or not to modulate the entire reference waveform Including data. In the fourth step, the reference waveform is conditionally modulated according to the flag. Thus, it is possible to conditionally modulate for each reference waveform.

  In a preferred aspect, the modulation item includes an item for selecting one of a plurality of types of modulation waveforms prepared in advance, and the parameter data is data indicating the type of the selected modulation waveform. including. In a fourth step, the selected modulation waveform is repeatedly superimposed on the reference waveform or line segment waveform element at a predetermined period. In this way, since a desired type can be selected from a plurality of modulation waveforms, the adaptability to the required specifications for laser processing can be expanded.

  In a preferred embodiment, a rectangular wave, a sine wave, and a sawtooth wave are prepared as modulation waveform types.

  In a preferred aspect, the modulation item includes an item for selecting whether to add or multiply as a method of superimposing the modulation waveform on the reference waveform or line segment waveform element, and the parameter data includes the modulation waveform It contains data specifying the superposition method. Then, in the fourth step, the selected modulation waveform is repeatedly added to the reference waveform or line segment waveform element at a certain period or repeatedly multiplied according to the instruction of the superposition method designation data. Here, when the addition superimposing method is selected, the amplitude of the AC component of the waveform can be kept constant throughout the entire duration of the reference waveform or the line segment waveform element. In addition, when the multiplication superposition method is selected, the amplitude of the alternating current component of the waveform can be varied according to the change rate of the reference waveform or the line segment waveform element. Thus, since a desired type can be selected from a plurality of modulation methods, the adaptability to the required specifications for laser processing can be expanded.

  In a preferred aspect, the modulation item includes an item for setting a desired duty for the rectangular waveform, and the parameter data includes data for instructing the desired duty for the rectangular waveform. In a fourth step, the modulation waveform of the rectangular wave is superimposed on the reference waveform or the line segment waveform element with the indicated duty. As described above, since the duty can be arbitrarily adjusted with respect to the modulation waveform of the rectangular wave, it is possible to widen the adaptability to the required specifications for laser processing.

  Further, in a preferred embodiment, the parameter data includes, for each line segment waveform element, initial value data representing a start value, change rate data representing a slope, and a line segment waveform element continuing from the start end. Line segment interval time data representing the length of time until the beginning of. In this case, in the fourth step, a change amount corresponding to the change rate data and the modulation waveform data is calculated for each constant period ΔT, and the change amount for the constant period ΔT is sequentially added starting from the initial value. Each line segment waveform element may be reproduced and modulated.

  The waveform generation period ΔT may be set to a common value (fixed value) over all line segment waveform elements, but may be determined according to the rate of change for each line segment waveform element. In that case, it is preferable that ΔT is shortened as the change rate of the line segment waveform element is increased, and ΔT is increased as the change rate of the line segment waveform element is decreased. That is, when the rate of change is large, the waveform generation cycle is shortened, and when the rate of change is small, the waveform generation cycle is lengthened, thereby making it possible to achieve both waveform reproduction accuracy and arithmetic processing efficiency.

  In a preferred aspect, the modulation waveform data is composed of a predetermined number of modulation data obtained by sampling the modulation waveform for one cycle at regular intervals on the time axis. Then, in the fourth step, the modulation data is used one by one along the time axis and repeatedly for the cycle period to calculate the change amount for a fixed period ΔT. Thus, since it is only necessary to prepare modulation waveform data for one cycle, the amount of data required for waveform modulation can be greatly reduced.

  The laser processing apparatus of the present invention has a reference waveform setting unit that sets a desired reference waveform by connecting a plurality of line segment waveform elements along a time axis, and predetermined modulation with respect to at least one of the line segment waveform elements. A modulation setting unit for setting the content of the specified item, a parameter data generation unit for generating parameter data including data representing the setting content of the modulation item for the entire reference waveform or each of the line segment waveform elements, and a time Along the axis, a predetermined calculation process is performed for each stage on the basis of the parameter data to reproduce and conditionally modulate the line segment waveform elements, thereby substantially connecting the line segment waveform elements over all stages. To restore the reference waveform. The laser output variable unit varies the output of pulsed or continuous oscillation laser light in accordance with the restored and modulated reference waveform, and performs laser processing with waveform control.

  In a preferred aspect of the present invention, the reference waveform setting unit, the modulation setting unit, and the parameter data generation unit are configured by a CPU (microcomputer), and the reference waveform restoration unit is constructed in an FPGA (field programmable gate array). The In this case, preferably, a modulation data storage unit for storing a predetermined number of modulation data obtained by sampling the waveform for one cycle at equal intervals on the time axis is provided in the FPGA. It's okay.

  In a preferred aspect, the laser output variable unit includes an optical resonator including an active medium for oscillating and outputting laser light, an excitation light source for optically exciting the active medium, and the excitation light source. A laser power source that supplies a driving current for light emission, a current measuring unit that measures the driving current, and a control unit that controls the driving circuit so that the measured value of the driving current follows the reference waveform.

  In another preferred aspect, the laser output variable section includes an optical resonator including an active medium for oscillating and outputting laser light, an excitation light source for optically exciting the active medium, and the excitation light source A laser power source for supplying a driving current for light emission, a laser output measuring unit for measuring the output of the laser light oscillated and output from an optical resonator, and the drive circuit so that the measured value of the laser output follows a reference waveform A control unit for controlling.

  According to the laser processing method or the laser processing apparatus of the present invention, with the configuration and operation as described above, the waveform modulation function in the laser power waveform control can be improved and the laser processing capability can be improved.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, the structure of the laser processing apparatus in one Embodiment of this invention is shown. This laser processing apparatus is configured as a fiber laser welding machine, and includes a fiber laser oscillator 10, a laser power source 12, a laser incident unit 14, a fiber transmission system 15, a laser emitting unit 16, a control unit 18, a touch panel 20, and the like. ing.

  The fiber laser oscillator 10 includes an oscillation optical fiber (hereinafter referred to as “oscillation fiber”) 22, an electro-optical excitation unit 24 that irradiates one end surface of the oscillation fiber 22 with pumping excitation light MB, and an oscillation fiber. 22 and a pair of optical resonator mirrors 26 and 28 that are optically opposed to each other via 22.

The electro-optic excitation unit 24 includes a laser diode (LD) 30 as an excitation light source and a condensing optical lens 32. LD30 is, LD drive current (or LD excitation current) is being driven to emit light supply or inject I _D from the laser power source 12, which oscillates and outputs a LD light clogging excitation light MB having a predetermined wavelength. The optical lens 32 condenses and enters the excitation light MB from the LD 30 onto one end surface of the oscillation fiber 22. The optical resonator mirror 26 disposed between the LD 30 and the optical lens 32 transmits the excitation light MB incident from the LD 30 side, and totally reflects the oscillation light incident from the oscillation fiber 22 side on the optical axis of the resonator. Is configured to do.

To measure the LD drive current I _D supplied to the laser power supply 12 than the LD34, the current sensor 25 and the LD current measurement circuit 27 are provided. The current sensor 25 is composed of, for example, a Hall element, and detects the LD drive current _ID without contact. LD current measurement circuit 27 inputs the output signal of the current sensor 25 a current measuring value of the LD drive current I _D (eg, current effective value) is calculated M _ID. The current measurement value M _ID obtained by the LD current measurement circuit 27 is supplied to the laser power source 12 as a feedback signal and to the control unit 18 as a monitor signal.

  Although not shown, the oscillation fiber 22 has a core doped with, for example, rare earth element ions as a light emitting element, and a clad surrounding the core coaxially. The core is used as an active medium, and the clad is used as the propagation of excitation light. The light path. The excitation laser beam MB incident on one end surface of the oscillation fiber 22 as described above propagates in the oscillation fiber 22 in the axial direction while being confined by total reflection at the cladding outer peripheral interface, and the core passes several times during the propagation. Across the core, photoexcites rare earth ions in the core. In this way, an oscillating light beam having a predetermined wavelength is emitted in the axial direction from both end faces of the core, and this oscillating light beam travels back and forth between the optical resonator mirrors 26 and 28 and is resonantly amplified. A fiber laser beam FB having the predetermined wavelength is extracted from the optical resonator mirror 28.

  In the optical resonator, the optical lenses 32 and 34 collimate the oscillating light beam emitted from the end face of the oscillation fiber 22 into parallel light and pass the collimated light to the optical resonator mirrors 26 and 28. The oscillating light beam reflected and returned by is condensed on the end face of the oscillating fiber 22. The excitation laser beam MB that has passed through the oscillation fiber 22 passes through the optical lens 34 and the optical resonator mirror 28 and is then folded back toward the side laser absorber 38 by the folding mirror 36. The fiber laser light FB output from the optical resonator mirror 28 passes straight through the folding mirror 36 and then passes through the beam splitter 40 before entering the laser incident portion 14.

The beam splitter 40 reflects a small portion (for example, 1%) of the incident fiber laser light FB in a predetermined direction, that is, the power sensor photosensor (PD) 42 side, and transmits the remaining most (99%) straight. Let A condensing lens 44 that condenses the reflected light from the beam splitter 40 or the monitor light R _FB is disposed in front of the photo sensor (PD) 42.

The photosensor (PD) 42 photoelectrically converts the monitor light R _FB from the beam splitter 40 and outputs an electrical signal (laser output measurement signal) representing the laser output (power) of the fiber laser light FB. The laser output measurement circuit 45 obtains the laser output measurement value M _FB of the fiber laser light FB by analog signal processing based on the output signal of the photosensor 42. The laser output measurement value M _FB obtained by the laser output measurement circuit 45 is supplied to the laser power source 12 as a feedback signal and to the control unit 18 as a monitor signal.

  The fiber laser beam FB that passes straight through the beam splitter 40 and enters the laser incident section 14 is first folded in a predetermined direction by the vent mirror 46, and then condensed by the condenser lens 50 in the incident unit 48 and transmitted through the fiber. The light is incident on one end face of a transmission optical fiber (hereinafter referred to as “transmission fiber”) 52 of the system 15. The transmission optical fiber 52 is made of, for example, an SI (step index) fiber, and transmits the fiber laser light FB incident in the incident unit 48 to the emission unit 54 of the laser emission unit 16. The emission unit 54 includes a collimator lens 56 that collimates the fiber laser light FB emitted from the end face of the transmission fiber 52 into parallel light, and a condensing lens 58 that condenses the parallel fiber laser light FB at a predetermined focal position. have.

When the laser welding is performed, the driving current I _D that is waveform control from the laser power source 12 is supplied (injected) to the LD 30, the fiber laser oscillator 10 within at LD 30 than the driving current I _D of the LD output waveform corresponding to the waveform The pumping light MB is supplied (injected) into the oscillation fiber 22, and the fiber laser oscillator 10 oscillates and outputs the fiber laser beam FB having a laser output waveform corresponding to the LD output waveform. The waveform-controlled fiber laser beam FB is focused and irradiated on a welding point or a welding line of the workpiece W through the laser incident portion 14, the fiber transmission system 15, and the laser emitting portion 16. At the welding point or welding line, the workpiece material is melted by the energy of the fiber laser beam FB, and solidifies after the pulse irradiation to form a nugget.

  In this fiber laser welding apparatus, the fiber laser oscillator 10 uses a fiber laser beam FB having a small beam diameter and a small beam divergence angle because the oscillation fiber 22 uses an elongated core having a diameter of about 10 μm and a length of several meters as an active medium. Can be output. Moreover, since the excitation laser light MB incident on one end face of the oscillation fiber 22 propagates through the long optical path of several meters in the oscillation fiber 22 and exhausts the excitation energy many times, the oscillation efficiency is very high. Thus, the fiber laser beam FB can be generated. The fiber laser oscillator 10 has a very stable beam mode because the core of the oscillation fiber 22 does not cause a thermal lens effect. As described above, since both the beam mode and the laser output are stable, the laser oscillation in the CW mode can be sustained for a maximum of about 100 seconds.

  As will be described later, this fiber laser welding apparatus enables arbitrary and various waveform control of the output (power) of the fiber laser beam FB, and greatly improves the waveform modulation function. It is possible to adjust the degree of penetration and the degree of finish more freely, and it can cope with strict requirements for precision welding with sufficient margin.

  Here, FIG. 2, FIG. 3 and FIG. 4 show basic forms (modes) of reference waveforms that can be set and input in this fiber laser welding apparatus. In any mode, a desired reference waveform is set by substantially connecting a plurality of line segment waveform elements along the time axis.

FIG. 2 shows an example of a reference waveform in the single oscillation mode. For example, it is possible to set an arbitrary pulse waveform duration T _A of 0.1～500Msec. The illustrated reference waveform A is formed by connecting _three line segment waveform elements a ₁ , a ₂ , and a ₃ .

FIG. 3 shows an example of a repetitive reference waveform in the repeat mode. For example, the repetition of the reference waveform A having a duration T _A of 0.1 to 500 msec can be set over a period T _{C of a} maximum of 99 seconds (fastest repetition frequency: 5 kHz).

FIG. 4 shows an example of a reference waveform in the CW mode. For example, it is possible to set an arbitrary continuous waveform duration 0.5~99sec T _B. The illustrated reference waveform B is formed by connecting seven line segment waveform elements b ₁ , b ₂ , b ₃ , b ₄ , b ₅ , b ₆ , and b ₇ .

  FIG. 5 shows a specific configuration example of the control unit 18 in this embodiment. As illustrated, the control unit 18 includes a CPU (microcomputer) 64, an FPGA (field programmable gate array) 66, a digital-analog (D / A) converter 68, an analog-digital (A) in terms of hardware. / D) converters 70 and 72 and a connecting device 74 are provided.

  The CPU 64 includes a central processing unit, a program memory, a data memory, an interface circuit, and the like, and controls the operation of the entire apparatus or each unit according to various programs (software) stored in the program memory. In particular, regarding the laser power waveform control, the CPU 64 inputs a reference waveform desired by the user (worker, maintenance worker, etc.) via the display unit 20 a and the input unit 20 b of the touch panel 20.

  In this embodiment, the CPU 64 does not sample and encode the reference waveform set and input through the touch panel 20 as it is in the prior art, but rather encodes the reference waveform on the time axis as a plurality of line segments. The data is decomposed into waveform elements, and parameter data indicating the characteristics of each line segment waveform element is generated. In this embodiment, for each line segment waveform element, that is, for each stage, (1) “initial value” data representing the starting value, (2) “change rate” data representing the slope, (3) "Line segment interval time" data indicating the length of time from the start to the start of the next line segment waveform element, and (4) "Modulation flag / resolution" indicating the user option and CPU setting scale for the modulation function and resolution, respectively. Four types of parameter data, “flag” data, are generated.

For example, taking the first line segment waveform element a ₁ of the reference waveform A of FIG. 2 as an example, as shown in FIG. 6, the “initial value” is the value of the start end q ₁ (usually 0), and “change rate” “ΔA (%) / ΔT (μsec)”, and “Line segment interval time” is N (pieces) × ΔT (μsec). Here, ΔT is not a sampling period but a period of calculation output or signal processing cycle for one time when each line segment waveform element is reproduced in the FPGA 66 as described later. Since ΔT is constant in each stage, data representing the numerical value N may be used as the “line segment section time” data.

Further, the “modulation flag” indicates whether or not to modulate a modulation waveform H of a certain cycle as shown in FIG. 7, for example, when reproducing the corresponding waveform element a ₁ on the FPGA 66 side. When the modulation flag is “0”, no modulation is applied, and when the modulation flag is “1”, the modulation is applied.

The “resolution flag” indicates a scale to be used for the “change rate” when the FPGA 66 reproduces the corresponding waveform element a ₁ . For example, the resolution flag “0” indicates a scale of [0.01% −1]. Here, [0.01% -1] means a scale in which [0.01%] is “1”. That is, when the ratio J of the unit change amount ΔA to the wave height reference value is 0.01% in percentage display, the “change rate” data ΔS is 1. Therefore, ΔS = 10 when J = 0.10%, and ΔS = 100 when J = 1.0%. On the other hand, the resolution flag “1” indicates a scale of [0.00001% −1]. That is, when the ratio J of the change rate ΔA to the wave height reference value is 0.00001% in percentage display, the “change rate” data ΔS is 1. Therefore, ΔS = 10 when J = 0.0001%, and ΔS = 100 when J = 0.001%.

For example, as shown in FIG. 8, when the slope (change rate) of the line segment waveform element a ₁ is normal or higher, a scale of [0.01% -1] is used, and the slope (change rate) is considerably small. Sometimes a scale of [0.00001% -1] is used.

  The CPU 64 manages the above four types of parameter data for one stage generated for each line segment waveform element in a set as shown in FIG. 9, for example.

  Further, the CPU 64 also generates basic parameter data of the entire reference waveform in a format as shown in FIG. 10, for example. Here, the “wave height reference value” corresponds to the denominator of “change rate” which is one of the stage parameters, and can be freely set by the user. For example, if the user sets the “wave height reference value” to 200 A for the LD drive current, J = 5% when the change amount ΔA per period ΔT is 10 A in the example of FIG. In this case, the CPU 64 adopts a scale of [0.01% −1] and generates “change rate” data of S = 500.

In FIG. 10, “repetition frequency” and “number of repetitions” are the repetition frequency (m / T _C ) and the number of repetitions (m) of the reference waveform in the repeat mode (FIG. 3). May be used. “Monitoring period designation” is a parameter for designating a mode (entire waveform or every constant period) for monitoring in the CW mode (FIG. 4), and the period can be variably set.

  “Modulation item content” indicates the setting content of an item predetermined with respect to the waveform modulation function together with the “modulation flag” of the stage parameter. More specifically, as shown in FIG. 11, “modulation waveform type”, “duty”, “superimposition method”, and “modulation flag” are prepared in the system as modulation items.

  In this embodiment, as shown in FIG. 12, three types of modulation waveforms such as (a) rectangular wave, (b) sine wave, and (c) sawtooth wave are prepared in the apparatus system, and the user can select among them. You can select the type you want. “Modulation waveform type” data (FIG. 11) indicates the type selected by the user.

  When a rectangular wave is selected, as shown in FIG. 13, for example, an arbitrary duty can be selected from 100 patterns from 0% to 100% at a pitch of δt. The “duty” data (FIG. 11) indicates the duty selected by the user.

  Furthermore, in this embodiment, as the method of superimposing the modulation waveform on the line segment waveform element or the reference waveform, there are two types of the apparatus system: (I) a method of adding modulation waveforms and (II) a method of multiplying modulation waveforms. It is prepared and the user can select either one. The “superimposition method” data (FIG. 11) indicates the superposition method ((I) or (II)) selected by the user.

  As shown in FIG. 14, for example, when the reference waveform A rises along the time axis at a positive rate of change, according to the superposition method (I), the amplitude of the AC component of the composite waveform [A + H] is constant and does not change. According to the superposition method (II), the amplitude of the AC component gradually increases as the level of the composite waveform [A × H] increases.

  The “modulation flag” data (FIG. 11) indicates whether or not the entire reference waveform is to be modulated, and is used alternatively with the “modulation flag” (FIG. 9) of the stage parameter data. Good.

  The CPU 64 associates the basic parameter data (FIG. 10) of the entire reference waveform with the parameter data (FIG. 9) for each line segment waveform element (stage) for one reference waveform, for example, in the format shown in FIG. Information is managed and stored in a data memory inside or outside the CPU. Although not shown, it is preferable to attach termination instruction data indicating that the nth stage is the final stage. In this embodiment, the provisional (n + 1) stage is defined, and the data N of the “segment time” is set to 0, so that the previous nth stage is the final stage. I am trying to show that.

  FIG. 16 shows a configuration example of various circuits constructed in the FPGA 66 in this embodiment. As shown, the FPGA 66 includes a data memory 80, a control circuit 82, a basic parameter data buffer memory 84, a stage parameter data buffer memory 86, a waveform restoration / modulation arithmetic circuit 88, a reference waveform output circuit 90, and modulation data. Memory 92, modulation data buffer 93, address counter 94, cycle counter 95, count comparison circuit 96, reference waveform integration circuit 98, current monitor waveform buffer memory 100, laser output monitor waveform buffer memory 102, current monitor waveform integration circuit 104, laser An output monitor waveform integration circuit 106, a comparison determination circuit 108, and the like are built in. A clock necessary for the operation of these circuits 80 to 108 is supplied from an external clock circuit 110.

  Prior to the start of laser welding, the data memory 80 is written with all parameter data (FIG. 15) relating to the reference waveform used in the laser welding by the CPU 64. The control circuit 82 receives a required control signal and various data related to the control from the CPU 64 and controls each part in the FPGA 66.

  The basic parameter data buffer memory 84 fetches and holds the basic parameter data (FIG. 10) of the entire reference waveform from the data memory 80 when executing the restoration process of the reference waveform. The stage parameter data buffer memory 86 fetches and holds the parameter data (FIG. 9) of the stage from the data memory 80 when executing the reproduction processing of each line segment waveform element.

  The waveform restoration / modulation arithmetic circuit 88 performs predetermined arithmetic processing on the basis of parameter data for each stage along the time axis under the control of the control circuit 82 to reproduce each line segment waveform element. A process of restoring the reference waveform by substantially connecting the line segment waveform elements is executed by a constant cycle (ΔT) calculation.

For this arithmetic processing, basic parameter data (FIG. 10) of the entire reference waveform is received from the basic parameter data buffer memory 84, and parameter data (FIG. 9) of each stage is received from the stage parameter data buffer memory 86 in the order of stages. The data of the modulation waveform H is received from the modulation data memory 92 via the modulation buffer 93.

In the modulation data memory 92, for each modulation waveform, for example, as shown in FIG. 17, a predetermined number, for example, 100 pieces of modulation data (h ₁ ) obtained by sampling the modulation waveform H for one cycle at regular intervals on the time axis. , H ₂ , h ₃ ,..., H ₁₀₀ ) are stored by memory mapping as shown in FIG. Address counter 94 constitute a DMA controller for reading out modulation modulated from the data memory 92 waveform data _{h p (p = 1,2, ··} , 100) one by one at a predetermined period (.DELTA.t).

  The “line segment interval time” data in the stage parameter data is supplied not to the arithmetic circuit 88 but to the count comparison circuit 96 as described later.

  The reference waveform output circuit 90 takes in the reproduction data CS of the line segment waveform element generated at a certain period (ΔT) from the waveform restoration / modulation operation circuit 88 and supplies the reproduction data CS of the line segment waveform element to the laser power source 12. A control signal is output at a predetermined timing.

  The cycle counter 95 and the count comparison circuit 96 constitute a timer circuit for measuring the duration (line segment interval time) of each stage in the waveform restoration / modulation processing. The cycle counter 95 is reset at the start of each stage, and is one for each period (ΔT) of restoration processing, for example, every time reproduction data CS of a line segment waveform element is output from the waveform restoration / modulation arithmetic circuit 88. Count up and output count value i.

  The count comparison circuit 96 compares the count value i from the cycle counter 95 with the data N of “line segment section time” held in the stage parameter data buffer memory 86, and when i reaches N, A stage end notification signal K is generated to notify that the stage has ended. When a stage end notification signal K is issued from the count comparison circuit 96, in response to this, the control circuit 82 overwrites and loads the next stage parameter data from the data memory 80 into the stage parameter data buffer memory 86. It has become.

  The reference waveform integration circuit 98 takes in and reproduces the reproduction data CS of the line segment waveform element output from the reference waveform output circuit 90 at a constant integration period, and calculates the integrated value of the reference waveform being reproduced.

The current monitor waveform buffer memory 100 latches the LD drive current measurement value M _ID sent from the LD current measurement circuit 27 via the connection circuit 74 and the A / D converter 70 (FIG. 5). The current monitor waveform integration circuit 104 takes in the LD drive current measurement value M _ID from the current monitor waveform buffer memory 100 at regular intervals and cumulatively adds it to obtain the integrated value of the LD drive current monitor waveform.

The laser output monitor waveform buffer memory 102 latches the laser output measurement value M _FB sent from the laser output measurement circuit 45 via the connection circuit 74 and the A / D converter 72 (FIG. 5). The laser output monitor waveform integration circuit 106 takes in the laser output measurement value _MFB from the laser output monitor waveform buffer memory 102 at regular intervals, accumulates it, and obtains an integrated value of the laser output monitor waveform.

  The comparison / determination circuit 108 integrates the integrated value of the reference waveform obtained by the reference waveform integration circuit 98 and the LD drive current monitor waveform obtained by the current monitor waveform integration circuit 104 every time one monitoring period ends. Or an integrated value of the laser output monitor waveform obtained by the laser output monitor waveform integrating circuit 106 to obtain a difference (error), and whether or not the error is within a predetermined allowable range. Is judged (good or bad judgment). And when the determination result of a defect comes out, this is transmitted to CPU64.

  Note that when the result of determination of failure is sent to the CPU 64, the monitor waveform data stored in the buffer memories 100 and 102 can also be sent to the CPU 64.

Although not shown, the laser power source 12 includes a DC power source, an LD drive circuit, a comparator, a feedback signal selection circuit, and the like. The DC power source is composed of, for example, an inverter circuit or a switching regulator circuit, and outputs a constant LD drive voltage. The LD drive circuit includes a V-I conversion circuit that generates an LD drive current _ID from the LD drive voltage, and is sent from the reference waveform output circuit 90 of the FPGA 66 through the D / A converter 68 and the connection circuit 74. The LD drive current _ID is varied so as to follow the analog reference waveform signal CS. The comparator inputs the reference waveform signal CS from the FPGA 66 as a command signal, and also inputs the LD drive current measurement value M _ID or the laser output measurement value M _FB as a feedback signal from the feedback signal selection circuit, and calculates the difference between both input signals. An error signal is output. The LD drive circuit varies the LD drive current _ID in a direction to make the error signal zero. Feedback signal selection circuit, under the control of the CPU 64, selects the LD drive current measurement value M _ID when applying feedback control for the LD drive current I _D, the feedback control for the output of the fiber laser beam FB When applying, the laser output measurement value _MFB is selected.

  FIG. 19 is a flowchart showing an overall processing procedure in the FPGA 66 in the single mode or repeat mode. This flow is started when a desired laser welding process is performed, and the entire sequence is controlled by the control circuit 82. Prior to this flow, as described above, all parameter data (FIG. 15) relating to the reference waveform used in this laser welding process is written from the CPU 64 to the data memory 80 of the FPGA 66.

First, the control unit 82 reads the basic parameter data of the entire reference waveform from the data memory 80 (FIG. 10), to load or set the basic parameters data buffer memory 84 (Step S _1).

Next, the control unit 82 accesses the data memory 80, reads the “line segment section time” data N in the stage parameter data to be read next (step S ₂ ), and N> 0 and N = 0. It is inspected (step S ₃ ). Since the first stage always exists, N> 0 and is valid. Therefore, the parameter data (FIG. 9) of the stage is read from the data memory 80 and set in the stage parameter data buffer memory 86 (step S). ₄ ).

Next, the control unit 82 causes the reference waveform restoration calculation circuit 88 to repeatedly perform a calculation process (step S ₅ ) for reproducing and modulating the line segment waveform element at a constant period (ΔT) (step S _5). → S ₈ → S ₉ → S ₁₀ → S ₅ . Reference waveform restoration operation circuit 88, a computation such as addition, subtraction, multiplication and division, obtains a unit modulation variation ΔA per certain period ΔT from the "change rate" data and "resolution" flag and "modulation item" data and modulation data h _p , The unit modulation change amount ΔA is added to the end of the line segment waveform element being reproduced at every fixed period ΔT starting from the “initial value” (q), and the line segment waveform element indicating the updated waveform end value is reproduced. Data CS is generated.

In addition, the control unit 82 provides the reference waveform output circuit 90 with a data output process (step S ₆ ) for outputting the reproduction data CS of the line segment waveform element generated by the reference waveform restoration calculation circuit 88 toward the laser power source 12. Repeatedly with a period (ΔU) (steps S ₅ → S ₆ → S ₉ → S ₁₀ → S ₆ ...). In parallel with this, the current monitor waveform buffer memory 100 and the laser output monitor waveform buffer memory 102 store the LD drive current measurement value M _ID and the laser output measurement value from the LD current measurement circuit 27 and the laser output measurement circuit 45, respectively. The monitor waveform data input process (step S ₆ ) for latching M _FB is repeatedly performed at regular intervals (steps S ₅ → S ₆ → S ₉ → S ₁₀ → S ₆ ...).

Further, the control unit 82 causes the reference waveform integration circuit 98 to repeatedly perform integration calculation processing (step S ₇ ) for integrating the reproduction data CS of the line segment waveform element output from the reference waveform output circuit 90 at a constant cycle (step S ₇ ). S ₅ → S ₇ → S ₉ → S ₁₀ → S ₇ . In parallel with this, the current monitor waveform integration circuit 104 and the laser output monitor waveform integration circuit 106 monitor the LD drive current measurement value M _ID and the laser output measurement value M _FB that are being monitored, respectively. The process (step S ₇ ) is repeatedly performed at a constant cycle (steps S ₅ → S ₇ → S ₉ → S ₁₀ → S ₇ ...).

  As described above, the reference waveform itself is not read out from the memory at the sampling period and the reference waveform is restored, but the FPGA 66 is based on a plurality of parameter data indicating characteristics or attributes of the reference waveform or each line segment waveform element. Since this is a method of restoring and modulating the reference waveform by repeating the calculation output for each fixed period (ΔT), the amount of data required for the reference waveform restoration processing and waveform modulation processing is significantly larger than that of the conventional CPU method (1 / 10 or less).

Further, waveform reproduction / modulation calculation processing (step S ₅ ) for each constant cycle (ΔT and ΔU) by the reference waveform restoration calculation circuit 88 as described above, and reproduction data output for each fixed cycle (ΔU) by the reference waveform output circuit 90. Processing and monitor waveform data input processing (step S ₆ ) by the current monitor waveform buffer memory 100 and the laser output monitor waveform buffer memory 102, reference waveform integration calculation processing for each fixed period by the reference waveform integration circuit 98, and current monitor waveform integration circuit 104 The monitor waveform integration calculation process (step S ₇ ) for each fixed period by the laser output monitor waveform integration circuit 106 does not require a bus cycle or a large number of machine cycles for one process unlike the CPU operation, and is a pipeline. Since it is performed by the method, the FPGA as a whole also has a substantially constant period ( It would operate at a speed of U).

  As described above, in this embodiment, the waveform reproduction period (ΔU) can be shortened as much as possible, and for example, ΔU = 5 μsec can be easily realized.

  Furthermore, in the waveform modulation function, it is possible to select the most suitable waveform from the multiple modulation waveforms (rectangular wave, sine wave, sawtooth wave) for the required specifications of laser welding processing. Since (I) a method of adding modulation waveforms and (II) a method of multiplying modulation waveforms can be used properly, it can be adapted to various needs of laser welding.

In FIG. 16, when the waveform reproduction cycle (ΔT) as described above is repeated N times, a count end notification signal K is generated from the count comparison circuit 96 at that time, and the process proceeds to the line segment waveform element reproduction process of the next stage. (Steps S ₉ → S ₁₁ → S ₂ ).

In the line segment waveform element reproduction processing, as shown in FIG. 20, the end of one stage line segment waveform element a _i is caused by an error in signal processing, so that the start of the next stage line segment waveform element a _{i + 1} ( Although it may be slightly deviated from the initial value (q _{i + 1} ), even in such a case, since both overlap each other on the time axis, it can be considered that the two stages are substantially connected. In the present invention, since the start of the line segment waveform element is initialized for each stage, there is also an advantage that the error of the waveform reproduction process is reset (corrected) by switching the stage.

When the last (n-th) stage line segment waveform element reproduction process is completed (step S ₃ ), the reference waveform restoration process is completed at that time, and the comparison determination circuit 108 determines whether the waveform control is good or bad ( step S ₁₂₎ is performed. In this embodiment, at this time, the waveform integration value of the entire reference waveform is obtained in the reference waveform integration circuit 98, and the LD drive current is supplied to the current monitor waveform integration circuit 104 and the laser output monitor waveform integration circuit 106. Since the integrated waveform values of the entire monitor waveform and the entire laser output monitor waveform are obtained, the comparison / determination circuit 108 obtains the difference (error) between the integrated waveform value of the entire reference waveform and the integrated waveform value of the entire monitor waveform. Therefore, it is sufficient to perform a calculation only to determine whether or not the error is within a predetermined allowable value or allowable range, and a pass / fail determination result can be obtained in a very short required time (within 0.1 msec).

In this embodiment, in repeat mode, if the duration T _A of the reference waveform is set to the shortest 0.1 msec, it is possible to easily realize a repetition frequency of 5 kHz.

  The pass / fail determination result obtained by the comparison determination circuit 108 is sent to the CPU 64 at all times or only when a failure result is obtained. The CPU 64 reports the pass / fail determination result (particularly the failure determination result) to the user through the touch panel 20, and displays the monitor waveform on the display of the display unit 20a as necessary.

In FIG. 16, steps S ₁₃ , S ₁₄ , and S ₁₅ are processes for repeating reference waveform reproduction a set number of times (m times) in the repeat mode.

  Although the flow in the CW mode is not shown, it is basically the same as the flow in the single mode or repeat mode described above. However, since the duration of the reference waveform is considerably long in the CW mode, if the entire waveform is continuously monitored, data overflows in the monitor waveform buffer memories 100 and 102.

  In this embodiment, the user can freely select an aspect (entire waveform or repetition of a fixed period) regarding the monitoring period of waveform control. In the single-shot mode or the repeat mode, normally, the duration of one waveform is one continuous monitoring period. On the other hand, in the CW mode, it is also possible to repeatedly perform monitoring at a constant cycle within the duration of one waveform, and the length of the cycle can be arbitrarily selected by the user. The contents selected or set by the user regarding the monitoring period are transmitted from the CPU 64 to the FPGA 66 through the “monitor period designation” data in the basic parameter data (FIG. 10) of the entire reference waveform.

  For example, when the user selects a repetition of a certain period and selects a monitor period of 3 seconds, the control circuit 82 on the FPGA 66 side through the data memory 80 and the reference waveform parameter data buffer memory 84 sets the monitor period setting value ( 3 seconds) is read and each of the pass / fail judgment sections (100 to 108) is repeatedly made to perform the same monitoring operation as described above every monitoring period (3 seconds). As a result, the comparison / determination circuit 108 outputs a pass / fail determination result for the monitor waveform (drive current waveform, laser output waveform) every monitor period (3 seconds). In this case, the monitor waveform buffer memories 100 and 102 do not overflow, and the waveform control quality can be determined with the same time resolution as the single-shot mode or repeat mode.

  In the above-described embodiment, the reference waveform integrated value obtained from the reference waveform restored in the FPGA 66 is compared with the monitor waveform integrated value to determine whether the laser waveform control is good or bad. As another embodiment, the CPU 64 side calculates a reference waveform integrated value based on the set reference waveform, and the FPGA 66 side compares the reference waveform integrated value with the monitor waveform integrated value to determine whether the laser waveform control is good or bad. It is also possible.

  In this case, when a desired reference waveform is input to the CPU 64 through the touch panel 20, the CPU 64 calculates the integration value of the reference waveform and displays the reference waveform integration value together with the reference waveform on the display of the display unit 20a. To do. A user (such as an operator) can adjust the waveform shape, duration, and the like of the reference waveform through the input unit 20b while looking at the reference waveform integral value displayed on the display. When the reference waveform desired by the user is determined, the CPU 64 generates the parameter data (FIGS. 9 to 11) as described above and stores it in the internal memory or the like, and the waveform integrated value of the reference waveform is also included. Save to. When the reference waveform is used for laser welding, the CPU 64 sends the integrated reference waveform value to the FPGA 66 together with all parameter data (FIG. 15) prior to the start of laser welding.

In the FPGA 66, the reference waveform integration value from the CPU 64 is directly loaded into the comparison determination circuit 108. The comparison judgment circuit 108 outputs the monitor waveform integration values from the monitor waveform integration circuits 104 and 106 when the laser welding process for one waveform is completed, that is, immediately after the restoration process for one time of the reference waveform is finished. Compared with the reference waveform integral value, the quality is judged based on the comparison error (step S ₁₂ ). Then, the result of pass / fail judgment is reported to the CPU 64 as described above.

Further, in the above embodiment, the waveform generating period ΔT within FPGA66, throughout the reference waveform, i.e. over all the segments waveform element (a ₁ ~a _n), was fixed to a common value. However, in the present invention, the individual segments waveform element a _1, a _2, method of setting the value of the waveform generating period ΔT independently for each · · a _n are also possible. In this case, the CPU 64 may set time data Ta _i (μsec) directly representing the duration of the line segment waveform element, that is, the stage time, as the “line segment section time” data in the stage parameter data. .

As shown in FIG. 21, a ΔT determination circuit 112 is provided in the FPGA 66. The ΔT determining circuit 112, the stage parameter data buffer "rate of change" from the memory 86 data ΔS and "line interval time" read data Ta _i, for example by referring to the table (memory), as shown in FIG. 22 The value (code) of the waveform generation period ΔT corresponding to the value of ΔS is selected. For example, when ΔS> 0.04, 5 μsec is selected as the value of the waveform generation period ΔT, and the code “0000” representing the value of ΔT (5 μsec) is transmitted from the ΔT determination circuit 112 to the control circuit 82 and the reference waveform restoration circuit. 88. When 1E-6 ≧ ΔS> 1E-7, 10 μsec is selected as the value of the waveform generation period ΔT, and the code “0001” representing the value of ΔT (10 μsec) is transmitted from the ΔT determination circuit 112 to the control circuit 82 and A reference waveform restoration circuit 88 is provided. Further, the ΔT determination circuit 112 calculates a set cycle count number N (N = Ta _i / ΔT) in the stage from the selected waveform generation period ΔT and the “line segment section time” Ta _i, and this set cycle The count number N is supplied to the count comparison circuit 96.

  As described above, according to the method of determining the waveform generation cycle ΔT according to the “change rate” for each stage, the waveform generation cycle ΔT is shorter as the change rate of the line segment waveform element is larger (the change rate is higher). The smaller the rate of change of the minute waveform element (the lower the rate of change), the longer the waveform generation period ΔT, and it is possible to achieve both the accuracy and efficiency of waveform restoration.

  It is also possible to set the waveform reproduction or output period ΔU in the FPGA 66 to a different period (for example, a fixed value) independently of the variable waveform generation period ΔT set on the CPU 64 side. In particular, when the waveform generation period ΔT is long, it is advantageous to set the waveform reproduction or output period ΔU to a short value.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above does not limit this invention. Those skilled in the art can make various modifications and changes in specific embodiments without departing from the technical idea and technical scope of the present invention.

  For example, in the waveform control function, the “modulation item content” data is included in the basic parameter data in the above embodiment, but may be included in the stage parameter data as another embodiment. In that case, “type of modulation waveform”, “duty”, and “modulation method” can be selected for each stage. It is also possible to fix the resolution to one type of scale. In this case, it is also possible to omit the “resolution flag” data in the stage parameter data.

  Further, various modifications can be made in each part of the fiber laser welding apparatus. For example, the fiber laser oscillator 10 can be replaced with a YAG laser oscillator or the like. The laser processing method and laser processing apparatus of the present invention are not limited to laser welding, and can be applied to other laser processing such as drilling, cutting, and marking.

It is a block diagram which shows the structure of the laser processing apparatus (fiber laser welding apparatus) in one Embodiment of this invention. An example of the reference waveform in single oscillation mode It is a figure which shows an example of the repetitive reference waveform in repeat mode. It is a figure which shows an example of the reference waveform in CW mode. It is a block diagram which shows the structure of the control part in the laser processing apparatus of embodiment. It is a figure for demonstrating the meaning of the initial value, change rate, and line segment area time which are contained in the parameter of the stage in embodiment. It is a figure for demonstrating the significance of the modulation flag contained in the parameter of the stage in embodiment. It is a figure for demonstrating the significance of the resolution flag contained in the parameter of the stage in embodiment. It is a figure which shows the example of a format of the parameter data of 1 stage in embodiment. It is a figure which shows the example of a format of the basic parameter data of the whole basic waveform in embodiment. It is a figure which shows the example of a format of the modulation item content data in embodiment. It is a wave form diagram which shows the kind of modulation waveform in embodiment. It is a wave form diagram which shows the adjustment method of the duty in embodiment. It is a wave form diagram which shows the kind of modulation method in embodiment. It is a figure which shows the example of a data format for collectively managing all the parameter data which concern on one basic waveform in embodiment. It is a block diagram which shows the circuit structure in FPGA in embodiment. It is a wave form diagram which shows the format of the data (modulation data) of the modulation waveform in embodiment. It is a figure which shows the example of the memory mapping in the modulation memory in embodiment. It is a flowchart figure which shows the whole process sequence of the circuit in FPGA in the single mode or repeat mode of embodiment. It is a figure which shows the example when the termination | terminus of a line segment waveform element shifts in embodiment. It is a block diagram which shows the circuit structure in FPGA in another embodiment. It is a figure which shows an example of the table used when changing a wave formation period according to the change rate of each line segment waveform element in embodiment. It is a block diagram which shows the circuit structure in FPGA in another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fiber laser oscillator 12 Laser power supply 16 Laser emission part 18 Control part 20 Touch panel 64 CPU (microcomputer)
66 FPGA (Field Programmable Gate Array)
80 Data Memory 82 Control Circuit 84 Basic Parameter Data Buffer Memory 86 Stage Parameter Data Buffer Memory 88 Waveform Restoration / Modulation Operation Circuit 90 Reference Waveform Output Circuit 92 Modulation Data Memory 93 Modulation Data Buffer Memory 94 Address Counter 95 Cycle Counter 96 Count comparison circuit 98 Reference waveform integration circuit 100 Current monitor waveform buffer memory 102 Laser output monitor waveform buffer memory 104 Current monitor waveform integration circuit 106 Laser output monitor waveform integration circuit 108 Comparison determination circuit 112 ΔT determination circuit

Claims (19)

A first step of connecting a plurality of line segment waveform elements along the time axis to set a desired reference waveform;
A second step of setting the content of a predetermined item with respect to modulation for at least one said line segment waveform element;
A third step of generating parameter data including data representing setting contents of the modulation item for the entire reference waveform or each of the line segment waveform elements;
Along with the time axis, each line segment waveform element is restored and each stage performing a predetermined calculation process based on the parameter data to reproduce and conditionally modulate the line segment waveform element, A fourth step of substantially joining the line segment waveform elements across the stage to restore the reference waveform;
A laser processing method comprising: a fifth step of varying an output of pulsed or continuous wave laser light used for desired laser processing according to the restored reference waveform. The modulation item includes an item for selecting whether to modulate each of the line segment waveform elements;
The parameter data includes flag data indicating whether or not to modulate each of the line segment waveform elements;
In the fourth step, each line segment waveform element is conditionally modulated according to the flag,
The laser processing method according to claim 1. The modulation item includes an item for selecting whether to modulate the entire reference waveform,
The parameter data includes flag data indicating whether to modulate the entire reference waveform;
In the fourth step, the reference waveform is conditionally modulated according to the flag,
The laser processing method according to claim 1. The modulation item includes an item for selecting one of a plurality of types of modulation waveforms prepared in advance,
The parameter data includes data indicating the type of the selected modulation waveform;
In the fourth step, the selected modulation waveform is repeatedly superimposed on the reference waveform or the line segment waveform element at a predetermined period.
The laser processing method as described in any one of Claims 1-3.   The laser processing method according to claim 4, wherein the modulation waveform includes a rectangular wave, a sine wave, and a sawtooth wave. The modulation item includes an item for selecting whether to add or multiply as a method of superimposing a modulation waveform on the reference waveform or the line segment waveform element,
The parameter data includes data indicating a method of superimposing the modulation waveform;
In the fourth step, according to the instruction of the superposition method designation data, the selected modulation waveform is repeatedly added to the reference waveform or the line segment waveform element at a constant period, or is repeatedly multiplied.
The laser processing method according to claim 4 or 5. The modulation item includes an item for setting a desired duty for a rectangular waveform.
The parameter data includes data indicating the desired duty for the modulation waveform of the rectangular wave;
In the fourth step, the modulation waveform of the rectangular wave is superimposed on the reference waveform or the line segment waveform element with the indicated duty.
The laser processing method according to claim 6.   The parameter data includes, for each of the line segment waveform elements, initial value data representing a start value, change rate data representing a slope, and a length of time from the start end to the start of the next line segment waveform element. The laser processing method as described in any one of Claims 1-7 including the data of the line segment area time showing thickness.   In the fourth step, a change amount according to change rate data and modulation waveform data is calculated for each constant cycle ΔT, and the change amount for the fixed cycle ΔT is sequentially obtained starting from the initial value. The laser processing method according to claim 8, wherein each line segment waveform element is reproduced by adding.   The laser processing method according to claim 9, wherein the period ΔT is determined according to the rate of change for each line segment waveform element. The modulation waveform data consists of a predetermined number of modulation data obtained by sampling the modulation waveform for one wavelength at equal intervals on the time axis,
In the fourth step, the modulation data is repeatedly used in a constant cycle independent of the period ΔT for calculating the change amount for the constant period ΔT one by one along the time axis.
The laser processing method according to claim 9 or 10. In the fifth step,
Measuring a driving current for light emission supplied to an excitation light source for optically exciting an active medium in an optical resonator that oscillates and outputs the laser light;
Varying the drive current so that the measured value of the drive current follows the restored reference waveform;
The laser processing method as described in any one of Claims 1-11. In the fifth step,
Measuring the laser output of the laser beam;
The emission drive current supplied to the excitation light source for optically exciting the active medium in the optical resonator that oscillates and outputs the laser light is varied so that the measured value of the laser output follows the reference waveform. To
The laser processing method as described in any one of Claims 1-11. A reference waveform setting unit for connecting a plurality of line segment waveform elements along the time axis to set a desired reference waveform;
A modulation setting unit for setting the content of a predetermined item regarding modulation for at least one of the line segment waveform elements;
A parameter data generation unit that generates parameter data including data representing the setting content of the modulation item for the entire reference waveform or each of the line segment waveform elements;
A predetermined calculation process is performed for each stage based on the parameter data along the time axis to reproduce and conditionally modulate the line segment waveform element, and substantially convert the line segment waveform element over all stages. A reference waveform restoration unit for connecting and restoring the reference waveform;
A laser processing apparatus comprising: a laser output variable unit configured to vary an output of pulsed or continuous wave laser light used for desired laser processing according to the restored reference waveform. The reference waveform setting unit, the modulation setting unit and the parameter data generation unit are constituted by a CPU (microcomputer),
The reference waveform restoration unit is constructed in an FPGA (Field Programmable Gate Array),
The laser processing apparatus according to claim 14.   16. A modulation data storage unit for storing a predetermined number of modulation data obtained by sampling a waveform for one cycle at equal intervals on a time axis for at least one modulation waveform is provided in the FPGA. The laser processing apparatus as described in. The CPU has a first modulation data storage unit that stores a predetermined number of modulation data obtained by sampling a waveform for one wavelength at equal intervals on a time axis for at least one modulation waveform;
A second modulation data storage unit for temporarily holding the modulation data is provided in the FPGA.
When the modulation waveform is used to modulate the reference waveform in the laser processing, the CPU reads the modulation data from the first modulation data storage unit and stores the second modulation data in the FPGA. The modulation data is read from the second modulation data storage unit in synchronization with the calculation processing of the reference waveform restoration unit,
The laser processing apparatus according to claim 15. The laser output variable unit is
An optical resonator including an active medium for oscillating and outputting the laser beam;
An excitation light source for optically exciting the active medium;
A laser power source for supplying a driving current for light emission to the light emitting unit;
A current measurement unit for measuring the drive current;
The laser processing apparatus according to claim 14, further comprising: a control unit that controls the drive circuit so that a measured value of the drive current follows the reference waveform. The laser output variable unit is
An optical resonator including an active medium for oscillating and outputting the laser beam;
An excitation light source for optically exciting the active medium;
A laser power supply for supplying a driving current for light emission to the excitation light source;
A laser output measuring unit for measuring the output of the laser beam oscillated and output from the optical resonator;
The laser processing apparatus according to claim 14, further comprising: a control unit that controls the drive circuit so that a measured value of the laser output follows the reference waveform.

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