Laser processing device

Abstract

The present invention prevents or suppresses any deviation of the irradiation position of measurement light with respect to the irradiation position of laser light resulting from thermal distortion. A laser processing device according to the present invention comprises: a processing head that includes at least one laser light deflection mechanism for irradiating a processing location on a workpiece with processing laser light; a processing head control device that controls the angle of the laser light deflection mechanism; an OCT scanner unit that includes at least one measurement light deflection mechanism for optically coupling measurement light used in measuring the distance to the workpiece to the laser light of the processing head; an OCT system controller that controls the angle of the measurement light deflection mechanism; at least one temperature sensor that is disposed inside or outside the processing head and the OCT scanner unit; and a correction unit that, on the basis of temperature information acquired from the temperature sensor, calculates correction data for correcting any deviation between the irradiation position of the laser light and the irradiation position of the measurement light resulting from thermal distortion caused by the temperature of the processing head or a measurement light unit.

Description

Laser Processing Equipment

[0001] The present disclosure relates to a laser processing apparatus.

[0002] Conventionally, there has been known a technique for measuring the displacement of a workpiece surface while processing the workpiece in a laser processing apparatus, as disclosed in Japanese Patent Application Laid-Open No. 2003-222111 and Japanese Patent Application Laid-Open No. 2003-222111.

[0003] JP 2021-37527 A JP 2017-131949 A

[0004] Ideally, the irradiation position of the laser beam used for processing and the irradiation position of the measurement beam used to measure the surface of the workpiece should coincide. However, due to an assembly error of the device or the like, a positional deviation may occur between the irradiation position of the laser beam and the irradiation position of the measurement beam. One way to deal with such a positional deviation is to correct the position based on data measured in advance.

[0005] However, errors between the laser beam irradiation position and the measurement beam irradiation position can occur due to thermal distortion. If the measurement beam irradiation position is misaligned from the laser beam irradiation position, the bottom of the keyhole in the workpiece may not be irradiated, and the depth of the keyhole bottom may not be accurately obtained.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide technology for a laser processing device that can prevent or suppress deviation of the irradiation position of measurement light from the irradiation position of laser light caused by thermal distortion.

[0007] The present disclosure relates to a laser processing apparatus comprising: a processing head including at least one laser light deflection mechanism for irradiating a processing location of a workpiece with processing laser light; a processing head control unit for controlling the angle of the laser light deflection mechanism; a measurement light unit including at least one measurement light deflection mechanism for optically coupling measurement light that measures the distance to the workpiece to the laser light of the processing head; a measurement light unit control unit for controlling the angle of the measurement light deflection mechanism; at least one temperature sensor arranged inside or outside the processing head and the measurement light unit; and a correction unit that calculates correction data for correcting a deviation between the irradiation position of the laser light and the irradiation position of the measurement light caused by thermal distortion due to the temperature of the processing head or the measurement light unit based on temperature information acquired from the temperature sensor.

[0008] According to the present disclosure, it is possible to provide a technology for a laser processing device that can prevent or suppress deviation of the irradiation position of measurement light from the irradiation position of laser light caused by thermal distortion.

[0009] FIG. 1 is a schematic diagram showing the configuration of a laser processing apparatus according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing the relationship between the irradiation position of laser light and the irradiation position of measurement light on the surface of a workpiece. FIG. 2 is a table showing the amount of correction deviation corresponding to temperature information from a temperature sensor. FIG. 3 is a schematic diagram explaining a learning model that outputs correction data from temperature information using a neural network in an eighth control example. FIG. 4 is a schematic diagram showing the configuration of a correction unit in the eighth control example. FIG. 5 is a schematic diagram explaining an example of correcting the laser irradiation position using a table in a tenth control example. FIG. 6 is a schematic diagram explaining an example of correcting the laser irradiation position using a table in a twelfth control example. FIG. 7 is a schematic diagram explaining a learning model that outputs correction data from temperature information using a neural network in a thirteenth control example. FIG. 8 is a schematic diagram explaining a learning model that outputs correction data from temperature information using a neural network in a fourteenth control example. FIG. 9 is a schematic diagram explaining a learning model that outputs correction data from temperature information using a neural network in a fifteenth control example. FIG. 10 is a schematic diagram showing the configuration of a laser processing apparatus of a modified example.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Fig. 1 is a schematic diagram showing the configuration of a laser processing apparatus 1 according to one embodiment of the present invention. The laser processing apparatus 1 shown in Fig. 1 performs welding by irradiating a processing beam onto a workpiece placed on a moving stage. Note that the laser processing apparatus 1 is not limited to a configuration in which the workpiece is placed on a moving stage, and the method of placing the workpiece can be changed as appropriate.

[0011] The configuration of the laser processing apparatus 1 of this embodiment will be described. The laser processing apparatus 1 includes a laser light source 11, a processing head 12, a processing head control device 20, an OCT (Optical Coherence Tomography) system 30, temperature sensors 71 to 80, and a correction unit 90.

[0012] The laser light source 11 generates laser light by internally oscillating a laser in response to a command (such as a laser power command) from the processing head control device 20. The laser light source 11 may be a fiber laser oscillator, a pulsed laser oscillator, a direct diode laser (DDL), a CO ２ The laser source 11 may be of any type, such as a laser oscillator, a solid-state laser (YAG laser) oscillator, etc. The laser source 11 supplies the generated laser light to the processing head 12.

[0013] In the machining head 12, laser light from the laser light source 11 is introduced through an entrance port 41, and the laser light is irradiated onto the workpiece through an exit port 42. Inside the machining head 12, optical components 50 such as lenses 51 to 53 and mirrors 54 to 56 are arranged.

[0014] The lens 51 is moved in the Z-axis direction by a Z-axis motor 91 that drives a belt. However, the lens 51 may be moved by a mechanism other than a belt, for example, by a cam mechanism. This movement moves the irradiation position of the laser light in the Z-axis direction. The mirror 54 is a dichroic mirror that reflects the processing beam while transmitting the measurement beam.

[0015] The processing head 12 may be configured with a wobble head having a wobble function, a galvanometer scanner, or a polygon mirror. The processing head 12 may also be a device placed on a moving stage or a device connected to a robot. Thus, the configuration of the processing head 12 is not particularly limited.

[0016] The laser beam deflection mechanism 13 controls the irradiation position by adjusting the positions and angles of the optical components 50, such as the mirrors 55 and 56, based on commands from the machining head control device 20. The orientation of the mirror 55 is changed by an X-axis motor 92, and controls the irradiation position of the laser beam in the X-axis direction. The orientation of the mirror 56 is changed by a Y-axis motor 93, and controls the irradiation position of the laser beam in the Y-axis direction.

[0017] The machining head control device 20 is configured using a computer including memories such as ROM (read only memory) and RAM (random access memory), a CPU (control processing unit), and a communication control unit, all connected via a bus. The functions and operations of each functional unit described below are achieved by the cooperation of the CPU and memory installed in the computer and the control program stored in the memory. The machining head control device 20 may be configured with a CNC (computer numerical controller) or a PLC (programmable logic controller), or may be connected to a higher-level computer that outputs machining conditions and the like in addition to the machining program.

[0018] The machining head control device 20 of this embodiment has a laser controller function and a scanner controller function, and is a control unit that controls the operations of the laser light source 11 and the laser light deflection mechanism 13 .

[0019] Various functions may be added to the machining head control device 20. For example, a welding monitoring system using an imaging element such as a C-MOS or CCD, or a welding monitoring system using a photodiode may be connected to the machining head control device 20.

[0020] The hardware relating to the various functions to be added to the processing head control device 20 may be installed independently, or may be installed by optically coupling with the processing head 12 or the OCT scanner unit 33 .

[0021] The OCT system 30 is a sensor system that determines the optical path length difference between the light reflected at the measurement point and the reference light from the interference fringes of the two lights. The OCT system 30 makes it possible to monitor the keyhole depth (≒weld depth) by measuring during welding. This makes it possible to directly determine the quality of the weld.

[0022] The OCT system 30 of this embodiment is an optical coherence interferometer unit including an OCT system controller 31 , a measurement light source 32 , and an OCT scanner unit 33 .

[0023] The OCT system controller 31 is a measurement light control unit that communicates with the processing head control device 20 and controls the operations of the measurement light source 32 and the OCT scanner unit 33 .

[0024] The measurement light source 32 is a light source that generates measurement light used in the optical coherence interferometer. The measurement light incident from the measurement light source 32 is introduced into the OCT scanner unit 33 through a lens 57. The lens 57 is moved in a predetermined direction via a belt by an OCT Z-axis motor 94 to adjust the irradiation position of the measurement light in the Z-axis direction. However, the lens 57 may also be moved by a mechanism other than a belt, and for example, the lens 57 may be moved by a cam mechanism.

[0025] The OCT scanner unit 33 is a measurement light unit having a measurement light deflection mechanism 34. The measurement light deflection mechanism 34 can be a device consisting of a galvanometer scanner or a polygon mirror. The measurement light deflection mechanism 34 of this embodiment has optical components 60 including mirrors 58 and 59. The mirror 58 is turned by an OCTX X-axis motor 95 to adjust the irradiation position of the measurement light in the X-axis direction. The mirror 59 is turned by an OCTY Y-axis motor 96 to adjust the irradiation position of the measurement light in the Y-axis direction. The measurement light deflection mechanism 34 operates based on commands from the OCT system controller 31. However, the deflection method of the measurement light deflection mechanism 34 is not particularly limited, and a parallel plate or the like may be used instead of a mirror.

[0026] The measurement light deflection mechanism 34 optically couples the measurement light to an optical path formed by an optical component 50 of the processing head 12. The measurement light deflection mechanism 34 causes the measurement light to be irradiated onto a mirror 54 of the processing head 12. The mirror 54 is a dichroic mirror that reflects the processing beam while transmitting the measurement light.

[0027] The temperature sensors 71 to 80 acquire temperature information for correcting the misalignment between the laser light irradiation position and the measurement light irradiation position caused by thermal distortion due to the temperature of the processing head 12 or the OCT scanner unit 33. Generally, processing heads (galvano scanners) often have built-in temperature sensors for control and safety reasons. By using these conventionally equipped temperature sensors, the present invention can be applied at low cost. Furthermore, the present invention can be applied to conventional devices without any additional hardware. However, a new temperature sensor may be added when applying the present invention.

[0028] The temperature sensors 71 and 72 are disposed inside the OCT scanner unit 33. The temperature sensor 71 acquires temperature information for taking into account the temperature drift of the OCTX axis motor 95. The temperature sensor 72 acquires temperature information for taking into account the temperature drift of the OCTY axis motor 96.

[0029] The temperature sensor 73 is disposed outside the processing head 12 and the OCT system 30. The temperature sensor 73 acquires temperature information of the outside air temperature to reflect thermal expansion due to overall temperature changes.

[0030] Temperature sensors 74, 75, and 76 are disposed inside the processing head 12. Temperature sensor 74 acquires temperature information of the incident port 41 in order to take into account the thermal effect of the lenses 51 to 53 due to the laser power of the laser light. Temperature sensor 75 acquires temperature information of the mirror 54 in order to take into account the angular misalignment of the combined portion of the laser light and the measurement light. Temperature sensor 76 acquires temperature information of the exit port 42 in order to take into account the thermal effect of the lenses 51 to 53 due to the laser power of the laser light.

[0031] The temperature sensors 77 and 78 are disposed in the OCT system 30. The temperature sensor 77 acquires temperature information of an input portion of cooling water that cools the OCT scanner unit 33 in order to take into account thermal expansion due to overall temperature changes in the OCT system 30. The temperature sensor 78 acquires temperature information of an output portion of cooling water that cools the OCT scanner unit 33 in order to take into account thermal expansion due to overall temperature changes in the OCT system 30.

[0032] The temperature sensor 79 and the temperature sensor 80 are disposed inside or outside the machining head 12. The temperature sensor 79 acquires temperature information of an input portion of cooling water that cools the machining head 12, in order to take into account thermal expansion due to overall temperature changes of the machining head 12 and the thermal effect of the lenses 51 to 53 due to the laser power of the laser light. The temperature sensor 80 acquires temperature information of an output portion of cooling water that cools the machining head 12, in order to take into account thermal expansion due to overall temperature changes of the machining head 12 and the thermal effect of the lenses 51 to 53 due to the laser power of the laser light.

[0033] The correction unit 90 is a calculation unit that uses temperature information acquired from the temperature sensors 71 to 80 to generate correction data that corrects the deviation between the irradiation position of the laser light and the irradiation position of the measurement light caused by thermal distortion due to temperature.

[0034] Here, the deviation between the irradiation position of the laser light and the irradiation position of the measurement light will be explained. Fig. 2 is a schematic diagram showing the relationship between the irradiation position of the laser light and the irradiation position of the measurement light on the surface of the workpiece.

[0035] Ideally, the laser beam and the measurement beam should be coaxially irradiated onto the workpiece. However, as shown in FIG. 2, due to assembly errors and other factors, the irradiation position of the measurement beam irradiated from the measurement beam deflection mechanism 34 may be coaxial at the center but not at the edges away from the center. In this case, it is possible to align the irradiation position of the laser beam with the position of the measurement beam by correcting the position of each laser beam irradiation position. For example, no position correction is necessary or only a small amount of correction is required at the center, but the amount of correction becomes greater at positions away from the center. However, even if there is no effect of misalignment due to assembly errors at the center, there is a risk of misalignment of the irradiation position due to thermal distortion. Even at the edges, position correction alone cannot align the irradiation position of the measurement beam with the irradiation position of the laser beam.

[0036] In this regard, the correction unit 90 of this embodiment can perform position correction that also takes thermal distortion into consideration based on the temperature information from the temperature sensors 71 to 80. Next, a method of position correction that takes temperature information into consideration will be described using several examples.

[0037] <Control Examples When the Origin Deviation is Minute> First, the first to eighth control examples will be described as examples of control when machining is performed near the origin, where there is no origin deviation due to position. For example, when the machining range of the laser machining device 1 is 300 x 300 mm, the first to eighth control examples are executed by controlling machining in a central area of ​​approximately 30 x 30 mm. In the following description, the origin deviation between the irradiation position of the machining laser and the irradiation position of the measurement light is assumed to be minute and is ignored.

[0038] Note that if the origin deviation is minute, it is not essential that the position be near the origin. Even if the position is not directly below the origin, as long as it is near the position where alignment was performed once, there will be no origin deviation due to position, so there is no need to consider position correction. For example, this is the case when alignment is performed when the workpiece cannot be placed directly below the laser processing device 1.

[0039] In the following description, T １ is the temperature sensor 71, T ２ is the temperature sensor 72, T ３ is the temperature sensor 73, T ４ is the temperature sensor 74, T ５ is the temperature sensor 75, T ６ is the temperature sensor 76, T ７ is the temperature sensor 77, T ８ is the temperature sensor 78, T ９ is the temperature sensor 79, T １０ indicates the temperature information of the temperature sensor 80.

[0040] <First Control Example> It is generally known that galvanometer motors are subject to temperature drift. Temperature drift is a major factor in the origin shift that causes deviations in the motor angle due to temperature. This temperature drift is not only caused by mechanical thermal expansion, but also by changes in the characteristics of electronic devices due to temperature. For example, an increase or decrease in resistance due to temperature change can cause a slight increase or decrease in the current when the same voltage is applied, which can affect the motor angle.

[0041] In the first control example, the origin deviation is corrected based on the temperature information of the temperature sensor 71 that measures the temperature of the OCTX axis motor 95 and the temperature information that measures the temperature of the OCTY axis motor 96 .

[0042] If the correction amount for correcting the irradiation position of the measurement light in the x-axis direction is defined as correction data x, the correction data x is calculated based on the temperature information (T １ ) with coefficient (a １ ) multiplied by a constant (b １ ) is created by adding

[0043]

[0044] Similarly, if the correction amount for correcting the irradiation position of the measurement light in the y-axis direction is defined as correction data y, the correction data y is calculated based on the temperature information (T ２ ) with coefficient (a ２ ) multiplied by a constant (b ２ ) is created by adding

[0045]

[0046] The correction unit 90 outputs the correction data x and the correction data y to the OCT system controller 31 , and reflects the correction data x and the correction data y in the control of the measurement light deflection mechanism 34 .

[0047] <Second control example> The origin deviation is caused by multiple factors. Therefore, more accurate correction can be performed by using a function as the correction formula. The correction data x is expressed as follows: n is the number of the temperature sensors 71 to 80, m is the coefficient numbering, a ｎｍ is the coefficient. １ is the temperature information of the temperature sensor 71, and T ２ is the temperature information of the temperature sensor 72. The correction data x can be calculated by the function of the following equation (3). Similarly, the correction data y can be calculated by the function of the following equation (4).

[0048]

[0049]

[0050] <Third Control Example> Incidentally, the galvanometer scanner (OCT scanner unit 33) is classified into an orthogonal system and a non-orthogonal system depending on the assembly method of the motors (OCTX axis motor 95, OCTY axis motor 96).

[0051] The orthogonal galvanometer scanner referred to here is a measurement light deflection mechanism 34 configured such that mirrors 58 and 59 are arranged orthogonally so that only the angle of the OCTX-axis motor 95 represents the x value and only the angle of the OCTY-axis motor 96 represents the y value. In the case of an orthogonal galvanometer scanner, while coordinate calculation is simple, mirrors 58 and 59 must be arranged at a distance so as not to come into contact with each other.

[0052] On the other hand, in a non-Cartesian galvanometer scanner, mirrors 58 and 59 are arranged obliquely rather than orthogonally, so the angle of the OCTX-axis motor 95 represents the x and y values, and the angle of the OCTY-axis motor 96 also represents the x and y values. Although coordinate calculations are more complex in a non-Cartesian galvanometer scanner, mirrors 58 and 59 can be arranged non-orthogonally, making it more advantageous than an orthogonal system in terms of space savings. That is, a non-orthogonal configuration can be achieved by considering the mirror shape, size, assembly angle, etc. to conserve space. In a non-orthogonal configuration, the distance between the two mirrors is smaller than in an orthogonal system, allowing the second mirror to be smaller. A smaller and lighter mirror reduces the motor torque, improving responsiveness. Furthermore, a smaller motor can be used.

[0053] Regarding origin deviation, if there are no other factors causing origin deviation other than the motors (OCTX-axis motor 95, OCTY-axis motor 96) and the system is ideally assembled in an orthogonal system, deviation in the x direction will be caused only by mirror 58. Deviation in the y direction will be caused only by mirror 59. However, as described above, in reality, due to assembly errors and a non-orthogonal system, both mirror 58 and mirror 59 are involved in origin deviation in the x direction, and both mirror 58 and mirror 59 are involved in origin deviation in the y direction.

[0054] Therefore, in the third control example, control is performed that takes into account the thermal distortion caused by the temperatures of both mirrors 58 and 59 when the origin is shifted in the x direction, and also takes into account the thermal distortion caused by the temperatures of both mirrors 58 and 59 when the origin is shifted in the y direction.

[0055] If the temperature of the OCTY-axis motor 96 causes deviations in not only the y direction but also the x direction, correction is made not only in the y direction but also in the x direction depending on the temperature of the OCTY-axis motor 96. Similarly, if the temperature of the OCTX-axis motor 95 causes deviations in not only the x direction but also the y direction, correction is made not only in the x direction but also in the y direction depending on the temperature of the OCTX-axis motor 95. x is T １ is multiplied by a coefficient, T ２ can be calculated by multiplying the coefficient and adding a constant. １ is multiplied by a coefficient, T ２This can be calculated by multiplying the temperature sensor number by a coefficient and adding a constant to the result. This can be expressed as the following equation (5). In equation (5), n corresponds to the temperature sensor number, x corresponds to the correction data in the x direction, and y corresponds to the correction data in the y direction.

[0056]

[0057] <Fourth Control Example> In the first to third control examples, the correction data is calculated using a formula, but the correction data can also be determined using a table. Figure 3 is a table showing the amount of correction deviation corresponding to the temperature information from the temperature sensors 71 to 80.

[0058] As shown in FIG. 3, in the fourth control example, the temperature information T １ The deviation amount of T is measured for each temperature, and a table of correction data x based on this deviation amount is created. During processing, correction data x corresponding to the temperature information is selected from the table. If the acquired temperature information is between the measured values ​​on the table, correction data x can also be determined by interpolation or extrapolation from two nearby points. For example, T １ If 23°C, x = 0.4 x ２０ +0.6 x x ２５ The correction data x can be calculated by

[0059] In addition, the temperature information T ２ By measuring the deviation amount for each temperature, the table of correction data y can be created in the same manner as the table of correction data x.

[0060] <Fifth Control Example> Origin deviation occurs due to thermal expansion of various parts of the device. For example, origin deviation is also affected by temperature changes inside the processing head 12. Because high-power laser light passes through the inside of the processing head 12, the influence of heat is significant. In particular, origin deviation may occur in the lenses 51 to 53 due to the thermal lens effect caused by heat input. Prediction accuracy can be improved by using not only the temperature sensors 71 and 72 inside the OCT scanner unit 33 but also the temperature sensors 74 to 76 inside the processing head 12.

[0061] In the first to fourth control examples, correction data was created based on the temperature information from the temperature sensor 71 of the OCTX axis motor 95 and the temperature information from the temperature sensor 72 of the OCTY axis motor 96, but in the fifth control example, correction data is created by taking into account the temperature information from the other temperature sensors 73 to 80.

[0062] The correction data x is T ｎ The correction data y can be calculated by adding a constant to the sum of the values ​​multiplied by the coefficient corresponding to each n. ｎ This correction data can be calculated by adding a constant to the sum of the values ​​multiplied by a coefficient corresponding to each n. The calculation of this correction data can be expressed based on the following formula (6). In formula (6), x is the correction data in the x direction, and y is the correction data in the y direction. ｎｘ , a ｎｙ n corresponds to the number of the temperature sensors 71 to 80, and a ０ｘ and a ０ｙ is a constant.

[0063]

[0064] <Sixth Control Example> In the fifth control example, the correction data was calculated based on the sum of the temperature information from the temperature sensors 71 to 80 multiplied by a coefficient, but by using a function for each n, it is possible to calculate correction data with even higher accuracy.

[0065] The correction data x is T ｎ Similarly, the correction data y can be calculated based on the sum of the values ​​of T ｎ is inserted into a function corresponding to each n. The calculation of this correction data can be expressed by the following formula (7). In formula (7), x and y correspond to the direction of the correction data, and n corresponds to the number of the temperature sensors 71 to 80.

[0066]

[0067] <Seventh Control Example> In the sixth control, the correction data in the x direction and the y direction are calculated, but the correction data in the z axis direction may also be calculated. In this case, as shown in Equation (8), T ｎThe correction data z in the z-axis direction is generated by adding up the values ​​of n into the corresponding function.

[0068]

[0069] <Eighth Control Example> In the first to seventh control examples, the correction data is determined based on a rule base, but the correction data can also be determined using a learning model that uses a neural network.

[0070] 4 is a schematic diagram illustrating a learning model that uses a neural network to output correction data from temperature information. As shown in FIG. 4, input data (input variables) are input as temperature information T ｎ A multivariate analysis model is constructed using a neural network with a data set (teaching data) in which labels (objective variables) are correction data for x, y, and z. The label x represents correction data for the x direction of the irradiation position of the measurement light, y represents correction data for the y direction of the irradiation position of the measurement light, and z represents correction data for the z direction of the irradiation position of the measurement light.

[0071] 5 is a schematic diagram showing the configuration of the correction unit 90 in the eighth control example. In this embodiment, the correction unit 90 has an information storage unit 97 that stores the multivariate analysis model. The correction unit 90 stores the temperature information T １ ~T ｎ When the temperature information is acquired as input data, it is input to the multivariate analysis model in the information storage unit 97. The multivariate analysis model generates correction data x, correction data y, and correction data z as output data. The correction unit 90 outputs the correction data x, correction data y, and correction data z generated by the multivariate analysis model to the OCT system controller 31. Temperature and thermal expansion spread with a time delay, but by using a learning model constructed by machine learning, it is possible to accurately output correction data without the need to reflect the time delay of temperature and thermal expansion using differential equations or the like.

[0072] The multivariable analysis model used by the correction unit 90 in the eighth control example can also be realized using the technology of a machine learning device disclosed in, for example, Japanese Patent Laid-Open No. 2019-111648 (Patent Application No. 2019-82287). In this case, the machine learning device is configured to include a measurement data acquisition unit that acquires a group of measurement data including temperature information, a thermal displacement amount acquisition unit that acquires actual measured values ​​of the thermal displacement of the mechanical elements of the laser processing apparatus 1, a memory unit that uses the group of measurement data acquired by the measurement data acquisition unit as input data and associates the actual measured values ​​of the thermal displacement of the mechanical elements acquired by the thermal displacement amount acquisition unit as labels and stores them as teacher data, and a calculation formula learning unit that performs machine learning based on the group of measurement data and the actual measured values ​​of the thermal displacement of the mechanical elements to set a thermal displacement amount prediction calculation formula that calculates the thermal displacement of the mechanical elements based on the group of measurement data. The calculation formula learning unit sets a thermal displacement prediction calculation formula based on the difference between an estimated value of the thermal displacement of the mechanical element calculated by substituting a group of measurement data for a predetermined period stored in the memory unit as training data into the thermal displacement prediction calculation formula, and an actual measured value of the thermal displacement of the mechanical element for a predetermined period stored as a label in the memory unit, and the thermal displacement prediction calculation formula uses multiple time shift elements of the temperature data included in the group of measurement data.

[0073] <Examples of control over a wide machining range where origin deviation occurs> As explained in Figure 2, at the ends far from the origin, positional deviation of the origin occurs due to assembly errors, etc. Next, ninth to fourteenth control examples will be explained as examples of control when laser machining is performed over a wide range where origin deviation occurs. The ninth to fourteenth control examples are performed, for example, in a range of x coordinate ±150 mm, y coordinate ±150 mm, and z coordinate 500 ±100 mm.

[0074] In the following description, the correction data for the positional deviation in the x direction caused by the thermal distortion is referred to as x Ｔ , y-direction correction data y Ｔ , z-direction correction data z Ｔ Let x Ｔ , y Ｔ , z Ｔ is calculated by the methods shown in the first to eighth control examples.

[0075] <Ninth Control Example> When the laser beam and the measurement beam are not completely coaxial, origin deviation occurs between the irradiation position of the laser beam and the irradiation position of the measurement beam. This origin deviation varies depending on the laser processing apparatus 1. In the ninth control example, it is assumed that a certain amount of deviation occurs depending on the location, regardless of the temperature. In other words, it is assumed that the position deviation caused by origin deviation and the position deviation caused by thermal distortion occur independently of each other. In this case, high-precision correction can be performed by adding the position correction data correcting the position deviation caused by origin deviation to the correction data correcting the position deviation caused by thermal distortion. Thus, in this control example, the correction data is a correction amount that corrects only the position deviation caused by thermal distortion, and the position correction data is described as a correction amount that corrects only the position deviation caused by origin deviation due to assembly errors, etc.

[0076] In the position correction data for correcting the position of the origin deviation, the position correction data of the x coordinate is ｐ , y-coordinate position correction data is ｐ , z-coordinate position correction data z ｐ The "p" indicates the position and is a subscript for distinguishing the thermal distortion correction data. These position correction data are calculated by a function that uses the laser irradiation positions X, Y, and Z as arguments. The position correction data x ｐ The function to calculate Ｘ (X, Y, Z), position correction data y ｐ The function to calculate Ｙ (X, Y, Z), position correction data z ｐ The function to calculate Ｚ Let (X, Y, Z). Position correction data in the x-, y-, and z-directions are calculated by inputting the laser irradiation positions X, Y, and Z into these functions. The functions are set, for example, based on data measured in advance.

[0077] By adding the correction data for correcting the thermal distortion to the position correction data, both the positional deviation caused by the origin deviation and the positional deviation caused by the thermal distortion are corrected. The correction data taking into account both the positional deviation caused by the origin deviation and the positional deviation caused by the thermal distortion can be expressed as in the following equation (9).

[0078]

[0079] <Tenth Control Example> Position correction data for correcting the origin deviation value depending on the position can also be determined using a table. By using a table, it is possible to determine the position correction data without calculating a complex function. Various methods can be used to determine the position correction data using such a table.

[0080] 6 is a schematic diagram illustrating an example of correcting the laser irradiation position using a table in the tenth control example. A plurality of candidates for position correction data for the laser irradiation position (X, Y, Z) are set in advance, and a table is created. During measurement, the correction unit 90 refers to the candidates (table) of position correction data corresponding to the laser irradiation position X, Y, Z, and determines the position correction data.

[0081] If the position correction data corresponding to the laser irradiation position is not found in the table, the position correction data is determined by interpolating the values ​​of the surrounding position correction data. ｐ , y ｐ , z ｐ Correction data x for correcting the positional deviation caused by thermal distortion Ｔ , y Ｔ , z Ｔ By adding these, correction data that takes into account the origin deviation and thermal distortion can be determined.

[0082] When interpolation is performed from m neighboring points, the position correction data can be expressed by the following formula (10): m in formula (10) is a natural number corresponding to the measurement points used for interpolation, and α ｍ is the interpolation / extrapolation ratio.

[0083]

[0084] <Eleventh Control Example> In the eleventh control example, the positional deviation caused by origin deviation also changes with temperature, even at the same position. Functions for calculating the correction amount at an arbitrary position and an arbitrary temperature are set for x, y, and z, respectively. The correction data in the eleventh control example indicates the correction amount for correcting both the positional deviation caused by thermal distortion and the positional deviation caused by origin deviation due to assembly error or the like.

[0085] A function for calculating correction data for correcting positional deviation caused by both thermal distortion and origin deviation can be expressed as the following formula (11) or formula (12): During laser processing, the correction data is calculated by substituting the laser irradiation position and temperature information into formula (11) or formula (12).

[0086]

[0087]

[0088] <Twelfth Control Example> In the eleventh control example, a function is used, but a table can also be used. In the twelfth control example, a table is used to determine the correction data. Various methods can be used to determine the position correction data using such a table.

[0089] FIG. 7 is a schematic diagram illustrating an example of correcting the laser irradiation position using a table in the twelfth control example. A table is created in which a plurality of candidates for position correction data for the laser irradiation position (X, Y, Z) are set in advance. For example, if the temperature T (T = T １ , T ２ ,... T ｎ ) Correction data x due to positional deviation ｐＴ (X, Y, Z, T), y ｐＴ (X, Y, Z, T), z ｐＴ A candidate (table) of (X, Y, Z, T) is created. During measurement, the correction unit 90 refers to the candidate (table) of correction data corresponding to the laser irradiation position X, Y, Z, and determines the correction data.

[0090] If there is no correction data at a certain position or temperature, the data is interpolated from the surrounding correction data. Any interpolation method can be used for the interpolation process. ｐＴ Since is n-dimensional data, an interpolation method in n-dimensional space is used. Note that weighting may be applied to each input data (X, Y, Z, T).

[0091] When interpolation is performed from m neighboring points, the correction data can be expressed by Equation (13). In Equation (13), m is a natural number corresponding to the measurement points used for interpolation, and α ｍis the interpolation / extrapolation ratio.

[0092]

[0093] <Thirteenth Control Example> In the ninth to twelfth control examples, the correction data is determined based on a rule base, but the correction data can also be determined using a learning model that uses a neural network.

[0094] 8 is a schematic diagram illustrating a learning model for outputting correction data from temperature information using a neural network in the thirteenth control example. As shown in FIG. 8, the temperature information T ｎ A multivariate analysis model is constructed using a neural network from a data set (teaching data) in which the laser irradiation position (X, Y, Z) is used as input data (input variables) and the label (objective variable) is correction data for x, y, and z. The label x is correction data for the x-direction of the irradiation position of the measurement light, y is correction data for the y-direction of the irradiation position of the measurement light, and z is correction data for the z-direction of the irradiation position of the measurement light.

[0095] The multivariate analysis model is stored in the information storage unit 97, similar to the description of Fig. 5. The multivariate analysis model may be realized, for example, using the technology disclosed in Japanese Patent Laid-Open No. 2019-111648 (Patent Application No. 2019-82287).

[0096] The correction unit 90 calculates the temperature information T ｎ (T = T １ , T ２ ,... T ｎ When the laser irradiation position (X, Y, Z) and the laser beam irradiation position (X, Y, Z) are acquired as input data, a multivariate analysis model is used to output correction data x, y, and z for the measurement beam irradiation position as output data. Temperature and thermal expansion spread with a time delay, but by using a learning model constructed by machine learning, it is possible to accurately output correction data without having to reflect the time delay of temperature and thermal expansion using differential equations, etc.

[0097] <Fourteenth Control Example> A learning model with different input data will be described. Fig. 9 is a schematic diagram illustrating a learning model that outputs correction data from temperature information using a neural network in the fourteenth control example.

[0098] In the fourteenth control example, in addition to temperature information and laser irradiation position, laser output information is also used as input data. The laser output information includes the laser diameter, power, time, frequency, duty, and numerical aperture (NA) of the optical fiber.

[0099] As shown in FIG. 9, the temperature information T ｎ A multivariate analysis model is constructed using a neural network with a dataset (teacher data) in which the laser irradiation position (X, Y, Z) and laser output information are used as input data (input variables) and the labels (objective variables) are correction data for x, y, and z.

[0100] The multivariate analysis model is stored in the information storage unit 97, similar to the description of Fig. 5. The multivariate analysis model may be realized, for example, using the technology disclosed in Japanese Patent Laid-Open No. 2019-111648 (Patent Application No. 2019-82287).

[0101] The correction unit 90 calculates the temperature information T ｎ (T = T １ , T ２ ,... T ｎ When the laser irradiation position (X, Y, Z) and laser output information are acquired as input data along with the laser irradiation position (X, Y, Z), correction data x, correction data y, and correction data z of the measurement light irradiation position are output as output data.

[0102] <Fifteenth Control Example> Coolant information, which is information about the coolant, can also be added to the input data. Fig. 10 is a schematic diagram illustrating a learning model that outputs correction data from temperature information using a neural network in the fifteenth control example.

[0103] In the fifteenth control example, in addition to the temperature information, the laser irradiation position, and the laser output information, cooling water information is also used as input data. The cooling water information includes the temperature of the cooling water at input, the temperature at output, the pressure and flow rate of the cooling water, etc. The cooling water information may be obtained by calculating the amount of change in heat quantity based on the flow rate and temperature change of the cooling water, and the amount of change in heat quantity may be used as input data.

[0104] As shown in FIG. 10, the temperature information T ｎ A learning model is constructed using a neural network from a dataset (teacher data) in which the laser irradiation position (X, Y, Z), laser output information, and cooling water information are used as input data (input variables), and the labels (objective variables) are correction data for x, y, and z.

[0105] The multivariate analysis model is stored in the information storage unit 97, similar to the description of Fig. 5. The multivariate analysis model may be realized, for example, using the technology disclosed in Japanese Patent Laid-Open No. 2019-111648 (Patent Application No. 2019-82287).

[0106] The correction unit 90 calculates the temperature information T ｎ (T = T １ , T ２ ,... T ｎ When the laser irradiation position (X, Y, Z), laser output information, and cooling water information are acquired as input data, correction data x, correction data y, and correction data z of the measurement light irradiation position are output as output data using a multivariate analysis model.

[0107] Although the configuration of the laser processing apparatus 1 has been described above, the laser processing apparatus 1 is not limited to this configuration. For example, correction data may be generated using temperature information from a location other than the temperature information detected by the temperature sensors 71 to 80.

[0108] 11 is a schematic diagram showing the configuration of a modified laser processing apparatus 1. In the modified example, the same components as or similar to those in the above embodiment are denoted by the same reference numerals in the drawing, and detailed description thereof will be omitted.

[0109] The laser processing device 1 of the modified example includes temperature sensors 101 to 110 in addition to the configuration of the laser processing device 1 of the above embodiment.

[0110] The temperature sensor 101 acquires temperature information of the joint between the processing head 12 and the OCT scanner unit 33 in order to take into account the influence of thermal distortion at the joint between the processing head 12 and the OCT scanner unit 33. The temperature sensor 102 acquires temperature information of the side surface of the processing head 12 in order to take into account the influence of thermal distortion outside the processing head 12 in the correction data. The temperature sensor 103 acquires temperature information of the side surface of the OCT scanner unit 33 in order to take into account the influence of thermal distortion outside the OCT scanner unit 33 in the correction data.

[0111] The temperature sensor 104 acquires temperature information of the lens 53 in order to take into account the influence of thermal distortion of the lens 53. The temperature sensor 105 acquires temperature information of the X-axis motor 92 in order to take into account the influence of temperature drift of the X-axis motor 92 of the machining head 12 in the correction data. The temperature sensor 106 acquires temperature information of the Y-axis motor 93 in order to take into account the influence of temperature drift of the Y-axis motor 93 of the machining head 12 in the correction data.

[0112] The temperature sensor 107 acquires temperature information of the OCT Z-axis motor 94 in order to incorporate the influence of temperature drift of the OCT Z-axis motor 94 into the correction data. The temperature sensor 108 acquires temperature information of the Z-axis motor 91 in order to incorporate the influence of temperature drift of the Z-axis motor 91 of the processing head 12 into the correction data. The temperature sensor 109 acquires temperature information of the sample arm of the measurement light source 32 in order to incorporate the deviation in the z-axis direction caused by thermal expansion of the measurement light path into the correction data. The temperature sensor 110 acquires temperature information of the optical fiber cable in order to incorporate the deviation in the z-axis direction caused by thermal expansion of the measurement light path into the correction data.

[0113] The correction unit 90 generates correction data using temperature information acquired from the temperature sensors 71 to 80 as well as temperature information acquired from the temperature sensors 101 to 110. The correction data can be generated using the methods described in the first to fifteenth control examples. Note that the correction unit 90 does not necessarily use all of the temperature information from the temperature sensors 71 to 80 and the temperature sensors 101 to 110, and may be configured to appropriately select the temperature information to be used depending on the processing conditions, the object to be processed, etc.

[0114] According to the laser processing device 1 of the present embodiment described above, the following effects are achieved.

[0115] The laser processing apparatus 1 of this embodiment includes a processing head 12 including at least one laser beam deflection mechanism 13 for irradiating a processing location of a workpiece as a workpiece with a processing laser beam, a processing head control device 20 for controlling the angle of the laser beam deflection mechanism 13, an OCT scanner unit 33 (measurement beam unit) including at least one measurement beam deflection mechanism 34 for optically coupling measurement beams for measuring the distance to the workpiece to the laser beam of the processing head 12, an OCT system controller 31 (measurement beam control unit) for controlling the angle of the measurement beam deflection mechanism 34, at least one temperature sensor 71 to 80, 101 to 110 arranged inside or outside the processing head 12 and the OCT scanner unit 33, and a correction unit 90 for calculating correction data for correcting a deviation between the irradiation position of the laser beam and the irradiation position of the measurement beam caused by thermal distortion due to the temperature of the processing head 12 or the OCT scanner unit 33 based on temperature information acquired from the temperature sensors 71 to 80, 101 to 110. This makes it possible to correct the deviation between the irradiation position of the laser light and the irradiation position of the measurement light caused by thermal distortion, thereby achieving highly accurate laser processing.

[0116] Furthermore, the correction unit 90 of this embodiment acquires data indicating the position of the processing point (laser light irradiation position (X, Y, Z)) from the processing head control device 20, calculates position correction data for correcting the position of the measurement light deflection mechanism 34, and the OCT system controller 31 adds the position correction data to the correction data to correct the position of the measurement light deflection mechanism 34. This makes it possible to more accurately correct the deviation in the irradiation position of the laser light and measurement light depending on the processing range and the characteristics of the metal to be processed. For example, even if the processing object is a metal such as pure aluminum, which has a thinner keyhole than iron, laser processing can be performed with high accuracy.

[0117] Furthermore, the correction unit 90 of this embodiment is created based on previously measured temperature information and data on the amount of deviation corresponding to the temperature information. It has a multivariate analysis model with the temperature information as an explanatory variable and the correction data as a target variable. During processing, the temperature information is acquired and correction data is calculated using the multivariate analysis model. This allows the temperature information from the temperature sensors 71-80 and 101-110, which are located in various parts such as the processing head 12 and the OCT scanner unit 33, to be reflected in the correction data using the multivariate analysis model, enabling higher-precision laser processing. Furthermore, by utilizing machine learning, it is possible to accurately output correction data without the need to reflect time delays in temperature and thermal expansion using differential equations, etc.

[0118] In this embodiment, the multivariate analysis model is created based on data on the amount of deviation corresponding to previously measured temperature information and machining point position data, with the temperature information and position data used as explanatory variables and the correction data used as the objective variable. During machining, the temperature information and machining point position data are acquired and the correction data is calculated using the multivariate analysis model. This allows various factors, such as the effects of temperature and thermal expansion and assembly errors, to be reflected in the correction data. Furthermore, correction data can be generated that can correct not only thermal distortion but also position deviations caused by assembly errors, without setting complex functions.

[0119] Furthermore, in this embodiment, the correction unit 90 acquires output information related to the output of the laser light and creates correction data taking this output information into account. This allows the laser light output information to be reflected in the correction data. Since the loss of laser light is directly converted into heat, the output information corresponds to temperature information. Furthermore, origin deviation also occurs due to the thermal lens effect caused by uneven heat input to the lenses 51 to 53. Since the effects of loss and thermal lens effect vary depending on the laser characteristics such as the laser diameter even with the same output, including laser output information in the input data can further improve prediction accuracy.

[0120] In this embodiment, the correction unit 90 acquires cooling water information about the cooling water that cools the processing head 12 or the OCT scanner unit 33, and creates correction data by taking the cooling water information into account. This allows the cooling water information, which is one of the factors that causes uneven temperature distribution and has a significant impact on temperature changes, to be reflected in the correction data, thereby further improving correction accuracy.

[0121] Furthermore, in this embodiment, at least one of the temperature sensors 74 to 76, 102, 104 to 106, and 108 is disposed on the processing head 12. This allows the thermal influence on the side irradiating the laser light to be reflected in the correction data, thereby further improving accuracy.

[0122] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0123] The following supplementary notes are further disclosed regarding the above-described embodiment and modified examples: (Supplementary Note 1) A processing head (12) including at least one laser beam deflection mechanism (13) for irradiating a processing location on a workpiece with a processing laser beam, a processing head control unit (20) for controlling the angle of the laser beam deflection mechanism (13), a measurement beam unit (33) including at least one measurement beam deflection mechanism (34) for optically coupling measurement beams for measuring the distance to the workpiece to the laser beam of the processing head (12), a measurement beam unit control unit (31) for controlling the angle of the measurement beam deflection mechanism (34), and at least one temperature sensor (71-80, 101-110) disposed inside or outside the processing head (12) and the measurement beam unit (33), a correction unit (90) that calculates correction data for correcting a deviation between the irradiation position of the laser light and the irradiation position of the measurement light that occurs due to thermal distortion caused by the temperature of the processing head (12) or the measurement light unit (33) based on temperature information acquired from the temperature sensors (71 to 80, 101 to 110).

[0124] (Appendix 2) In the above laser processing device (1), the correction unit (90) acquires data indicating the position of the processing point from the processing head control unit (20) and calculates position correction data for correcting the position of the measurement light deflection mechanism, and the measurement light unit control unit (31) adds the position correction data to the correction data to correct the position of the measurement light deflection mechanism (34).

[0125] (Supplementary Note 3) In the above laser processing device (1), the correction unit (90) has a multivariate analysis model that is created based on the temperature information measured in advance and data on the amount of deviation corresponding to the temperature information, and has the temperature information as an explanatory variable and the correction data as a target variable, and during processing, acquires the temperature information and calculates the correction data using the multivariate analysis model.

[0126] (Note 4) In the above laser processing device (1), the multivariate analysis model is created based on data of deviation amounts corresponding to the temperature information and processing point position data measured in advance, the temperature information and the position data are the explanatory variables, and the correction data is the objective variable, and during the processing, the temperature information and the processing point position data are acquired, and the correction data is calculated using the multivariate analysis model.

[0127] (Supplementary Note 5) In the above laser processing device (1), the correction unit (90) acquires output information relating to the output of the laser light, and creates the correction data by taking the output information into consideration.

[0128] (Appendix 6) In the above laser processing device (1), the correction unit (90) acquires cooling water information regarding the cooling water that cools the processing head (12) or the measurement light unit (33), and creates the correction data by taking the cooling water information into account.

[0129] (Supplementary Note 7) At least one of the temperature sensors (74 to 76, 102, 104 to 106, 108) is disposed in the processing head.

[0130] REFERENCE SIGNS LIST 1 Laser processing device 11 Laser light source 12 Processing head 13 Laser light deflection mechanism 20 Processing head control device (processing head control unit) 31 OCT system controller (measurement light control unit) 33 OCT scanner unit (measurement light unit) 34 Measurement light deflection mechanism 90 Correction unit

Claims

1. A laser processing device comprising: a processing head including at least one laser beam deflection mechanism for irradiating a processing location on a workpiece with a processing laser beam; a processing head control unit for controlling the angle of the laser beam deflection mechanism; a measurement beam unit including at least one measurement beam deflection mechanism for optically coupling measurement beams that measure the distance to the workpiece with the laser beam of the processing head; a measurement beam unit control unit for controlling the angle of the measurement beam deflection mechanism; at least one temperature sensor disposed inside or outside the processing head and the measurement beam unit; and a correction unit for calculating correction data based on temperature information acquired from the temperature sensor to correct a deviation between the irradiation position of the laser beam and the irradiation position of the measurement beam that occurs due to thermal distortion caused by the temperature of the processing head or the measurement beam unit.

2. The laser processing device described in claim 1, wherein the correction unit obtains data indicating the position of the processing point from the processing head control unit and calculates position correction data for correcting the position of the measurement light deflection mechanism, and the measurement light unit control unit adds the position correction data to the correction data to correct the position of the measurement light deflection mechanism.

3. The laser processing device according to claim 1, wherein the correction unit has a multivariate analysis model created based on the temperature information measured in advance and data on the amount of deviation corresponding to the temperature information, the multivariate analysis model having the temperature information as an explanatory variable and the correction data as a target variable, and during processing, the temperature information is acquired and the correction data is calculated using the multivariate analysis model.

4. The laser processing device according to claim 3, wherein the multivariate analysis model is created based on data on the amount of deviation corresponding to the temperature information and processing point position data measured in advance, the temperature information and the position data are the explanatory variables and the correction data are the objective variables, and during processing, the temperature information and the processing point position data are acquired and the correction data is calculated using the multivariate analysis model.

5. A laser processing device according to any one of claims 1 to 4, wherein the correction unit acquires output information relating to the output of the laser light and creates the correction data by taking the output information into account.

6. A laser processing device as described in any one of claims 1 to 5, wherein the correction unit acquires cooling water information regarding the cooling water that cools the processing head or the measurement light unit, and creates the correction data by taking the cooling water information into account.

7. The laser processing device according to any one of claims 1 to 6, wherein at least one temperature sensor is disposed in the processing head.

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