JP7285465B2 - LASER PROCESSING DEVICE, LASER PROCESSING METHOD, AND CORRECTION DATA GENERATION METHOD - Google Patents

Description

The present disclosure relates to a laser processing apparatus, a laser processing method, and a correction data generation method used for processing objects to be welded.

Patent Literature 1 discloses a laser processing apparatus. This laser processing apparatus uses OCT (Optical Coherence Tomography) technology, which visualizes the structure inside a sample using an optical interferometer, to measure the depth of a keyhole generated during metal processing by laser light.

Here, the laser processing apparatus of Patent Document 1 will be described with reference to FIG. 23 . FIG. 23 is a diagram schematically showing the configuration of the laser processing apparatus disclosed in Patent Document 1. As shown in FIG.

A processing laser beam 107 and a measurement beam 105 are introduced into the welding head 108 . The measurement light 105 passes through the collimator module 106 and the dichroic mirror 110 and becomes coaxial with the processing laser light 107 sharing the optical axis.

As a measuring device, an OCT optical system using an optical interferometer comprising an analysis unit 100, an optical fiber 101, a beam splitter 103, an optical fiber 104, a reference arm 102, and a measurement arm 109 is configured. The measurement light 105 is emitted through the optical fiber 104 as OCT measurement light.

The processing laser beam 107 and the measurement beam 105 are condensed by a condensing lens 111 and applied to a workpiece 112 . The workpiece 112 is processed by the processing laser beam 107 . When the processed portion 113 of the workpiece 112 is irradiated with the focused processing laser beam 107, the metal forming the workpiece 112 is melted, and a keyhole is formed by the pressure when the molten metal evaporates. The measurement light 105 is applied to the bottom surface of the keyhole.

An interference signal is generated according to the optical path difference between the measurement light 105 (reflected light) reflected by the keyhole and the light (reference light) on the reference arm 102 side. The depth of the keyhole can be determined from this interference signal. The keyhole is filled with surrounding molten metal immediately after formation. Therefore, the depth of the keyhole is substantially the same as the depth of the melted portion (also called penetration depth) of the metal working portion. Therefore, the penetration depth of the processed portion 113 can be measured.

Japanese Patent Publication No. 2013-501964

2. Description of the Related Art In recent years, a laser processing apparatus that combines a galvanomirror and an fθ lens is known. The galvanomirror is a first mirror that can precisely control the direction in which the laser light is reflected. The fθ lens is a lens that converges laser light onto a processing point on the surface of the workpiece.

However, when the method of measuring the depth of the keyhole disclosed in Patent Document 1 is applied to a laser processing apparatus that combines a galvanomirror and an fθ lens, the following problems arise. That is, since the wavelengths of the laser light for processing and the light for measurement are different, and the f-theta lens has the characteristic of causing chromatic aberration, the laser light for processing and the light for measurement are deviated from each other on the surface of the workpiece. There is a problem that the thickness cannot be measured accurately.

An object of one aspect of the present disclosure is to provide a laser processing apparatus, a laser processing method, and a correction data generation method that can accurately measure the depth of a keyhole.

A laser processing apparatus according to an aspect of the present disclosure includes a laser oscillator that oscillates a processing laser beam to a processing point on a surface of a workpiece, and a measurement beam that emits a measurement beam to the processing point. an optical interferometer that generates an optical interference intensity signal based on interference caused by an optical path difference between the reflected measurement light and the reference light; a first mirror that changes traveling directions of the processing laser light and the measurement light; a second mirror for changing the angle of incidence of the measurement light on the first mirror; a beam shift mechanism for changing the position of incidence of the measurement light on the first mirror; a lens for converging light on the processing point; a memory for storing corrected processing data; and the laser oscillator, the first mirror, the second mirror, and the beam shift mechanism based on the corrected processing data. and a measurement processing unit that measures the depth of the keyhole generated at the processing point by being irradiated with the processing laser light based on the optical interference intensity signal, The corrected processing data is processing data generated in advance for processing of the work piece, and the work piece is at a reaching position of at least one of the processing laser light and the measurement light caused by the chromatic aberration of the lens. and the deviation between the angle of the keyhole and the angle of the measurement light.

A laser processing method according to an aspect of the present disclosure includes a first mirror that changes traveling directions of a processing laser beam and a measurement light, a second mirror that changes an incident angle of the measurement light to the first mirror, A laser processing apparatus having a beam shift mechanism that changes the incident position of the measurement light on the first mirror, and a lens that converges the processing laser light and the measurement light on a processing point on the surface of the workpiece. wherein the first mirror, the second mirror, and the beam shift mechanism are controlled based on the corrected processing data, and the processing laser light and the measurement light are applied to the workpiece. The depth of the keyhole generated at the processing point by being irradiated with the processing laser light based on the interference caused by the optical path difference between the measurement light and the reference light reflected at the processing point The corrected processing data is the processing data generated in advance for processing the workpiece, and the arrival of at least one of the processing laser light and the measurement light caused by the chromatic aberration of the lens. This data is corrected so as to eliminate position deviation on the surface of the workpiece and deviation between the angle of the keyhole and the angle of the measurement light.

A correction data generation method according to an aspect of the present disclosure includes a first mirror that changes traveling directions of a processing laser beam and a measurement light, and a second mirror that changes an incident angle of the measurement light to the first mirror. , a laser processing apparatus having a beam shift mechanism that changes the incident position of the measurement light on the first mirror, and a lens that converges the processing laser light and the measurement light on the surface of the workpiece. In the correction data generation method, the output intensity of the processing laser light and the operation of the first mirror for causing the processing laser light to reach the processing point for each processing point on the surface of the workpiece. A first mirror which is an operation amount of the second mirror for generating the processing data in which the amount and the amount are set and causing the measurement light to reach the predetermined position for each predetermined position on the surface of the workpiece. calculating a movement amount, and calculating a second movement amount, which is a movement amount of the second mirror for causing the measurement light to reach the processing point, based on the first movement amount, for each processing point; calculating a third operation amount, which is an operation amount of the beam shift mechanism for causing the measurement light to reach the predetermined position, for each predetermined position and processing speed on the surface of the workpiece; calculating a fourth operation amount, which is an operation amount of the beam shift mechanism for causing the measurement light to reach the processing point, based on the amount, and calculating the second operation amount and the fourth operation amount for each of the processing points; By adding the amount to the processing data, the displacement of the arrival position of at least one of the processing laser light and the measurement light on the workpiece caused by the chromatic aberration of the lens, and the angle of the keyhole and the Corrected processing data corrected so as to eliminate the deviation from the angle of the measurement light is generated.

According to the present disclosure, it is possible to accurately measure the depth of the keyhole.

A diagram schematically showing the configuration of a laser processing apparatus according to an embodiment of the present disclosure The figure which shows typically the laser processing apparatus in the state which operated the 1st mirror from the origin position. FIG. 4 is a diagram schematically showing the laser processing apparatus in a state in which deviations in the arrival positions of the processing laser light and the measurement light due to the chromatic aberration of magnification are corrected; A diagram schematically showing an example of the state of formation of a keyhole when the processing speed is high FIG. 4 is a diagram schematically showing the laser processing apparatus in a state in which angular deviations between the keyhole forming axis and the measurement optical axis of the measurement light are corrected; A diagram schematically showing the trajectories of the processing laser beam and the measurement beam on the processing surface when only the first mirror is operated and the surface of the workpiece is scanned in a grid pattern. Flowchart showing a first example of a method for creating first correction table data Flowchart showing a second example of a method for creating the first correction table data Flowchart showing method for creating correction formula table data for position correction movement amount Flowchart showing method for creating correction formula table data for speed correction movement amount Diagram showing correction formula table data for speed correction movement amount A diagram showing an example of the configuration of corrected processing data Flowchart showing how to create processing data A diagram showing a correction number table that schematically represents the configuration of the correction number table data Flow chart showing how to set the correction angle A diagram showing the relationship between the scanning angle X and the correction data points around it when the scanning angle X set by the user does not match the scanning angle for the correction formula table of any data point on the correction formula table. Flowchart showing how to set the compensation movement amount Flowchart showing the laser processing method Flowchart showing keyhole depth measurement method A diagram schematically showing the trajectories of the processing laser light and the measurement light on the processing surface in a state where the influence of the chromatic aberration of magnification is corrected by the operation of the second mirror. A diagram schematically showing the configuration of a laser processing apparatus according to Modification 1 of the present disclosure A diagram schematically showing the configuration of a laser processing apparatus according to Modification 4 of the present disclosure A diagram schematically showing a laser processing apparatus disclosed in Patent Document 1

Embodiments of the present disclosure will be described below with reference to the drawings. In addition, the same code|symbol is attached|subjected about the component which is common in each figure, and those description is abbreviate|omitted suitably.

[Configuration of laser processing device]
A configuration of a laser processing apparatus 1 according to an embodiment of the present disclosure will be described using FIG. FIG. 1 is a diagram schematically showing the configuration of a laser processing apparatus 1 according to this embodiment.

The laser processing apparatus 1 has a processing head 2 , an optical interferometer 3 , a measurement processing section 4 , a laser oscillator 5 , a control section 6 , a first driver 7 , a second driver 8 and a third driver 41 .

The optical interferometer 3 emits measurement light 15 for OCT measurement. The emitted measurement light 15 is input to the processing head 2 from the measurement light introduction port 9 . The measuring light inlet 9 is installed on the second mirror 17 .

A laser oscillator 5 oscillates a processing laser beam 11 for laser processing. The oscillated processing laser beam 11 is input to the processing head 2 from the processing light inlet 10 .

The processing laser beam 11 input to the processing head 2 passes through the dichroic mirror 12, is reflected by the first mirror 13, passes through the lens 14, and is focused on the processing surface 19 of the surface of the workpiece 18. . Thereby, the processing point 20 of the workpiece 18 is laser-processed. At this time, the processing point 20 irradiated with the processing laser beam 11 is melted to form a molten pool 21 . Further, the molten metal evaporates from the molten pool 21, and the keyhole 22 is formed by the vapor pressure generated during the evaporation.

The measurement light 15 input to the processing head 2 is converted into parallel light by the collimator lens 16 , reflected by the second mirror 17 , and transmitted through the beam shift mechanism 38 . After that, the measurement light 15 is reflected by the dichroic mirror 12 , reflected by the first mirror 13 , transmitted through the lens 14 , and condensed at the processing point 20 on the surface of the workpiece 18 . Then, the measurement light 15 is reflected by the bottom surface of the keyhole 22 , traces the propagation path, reaches the optical interferometer 3 , and generates an interference signal by optical interference with the reference light (not shown) within the optical interferometer 3 .

The measurement processing unit 4 measures the depth of the keyhole 22, that is, the penetration depth of the processing point 20 from the interference signal. The penetration depth means the distance between the highest vertex of the melted portion of the workpiece 18 and the processing surface 19 .

The wavelength of the processing laser light 11 and the wavelength of the measurement light 15 are different from each other. The dichroic mirror 12 has the characteristic of transmitting the light of the wavelength of the processing laser light 11 and reflecting the light of the wavelength of the measurement light 15 .

For example, when a YAG laser or fiber laser is used as the processing laser 11, the wavelength of the processing laser 11 is 1064 nm. Further, for example, when an OCT light source is used as the measurement light 15, the wavelength of the measurement light 15 is 1300 nm.

The first mirror 13 and the second mirror 17 are movable mirrors that can be rotated on two or more axes. The first mirror 13 and the second mirror 17 are, for example, galvanometer mirrors.

The first mirror 13 and the second mirror 17 are connected to the controller 6 via the first driver 7 and the second driver 8 respectively, and operate under the control of the controller 6 . The first driver 7 operates the first mirror 13 based on instructions from the control unit 6 . The second driver 8 operates the second mirror 17 based on instructions from the control unit 6 .

The controller 6 has a memory 31 . The memory 31 stores processing data for performing desired processing on the workpiece 18 and correction data for performing correction described later.

As an example, FIG. 1 shows only the rotational movement of each of the first mirror 13 and the second mirror 17 about the rotation axis in the y direction (see the dotted line and double arrows in the figure). However, in practice, the first mirror 13 and the second mirror 17 are each configured to be rotatable on two or more axes as described above. Therefore, each of the first mirror 13 and the second mirror 17 can also rotate about the rotation axis in the x direction, for example.

For the sake of simplification, only the case where each of the first mirror 13 and the second mirror 17 rotates about the rotation axis in the y direction will be described below.

When the second mirror 17 is at the origin position, the measurement optical axis 23 of the measurement light 15 is reflected by the dichroic mirror 12 and then coincides with the processing optical axis 24 of the processing laser light 11 .

Further, when the first mirror 13 is at the origin position, the processing optical axis 24 of the processing laser beam 11 is reflected by the first mirror 13 and then transmitted through the lens 14, and is at the center of the lens 14. It coincides with the lens optical axis 25 .

In the following description, the position (which may be called the irradiation position) at which the processing laser beam 11 and the measurement light 15 that have passed through the center of the lens 14 reach the processing surface 19 of the workpiece 18 is referred to as the "processing origin. 26” (see FIG. 2). That is, the origin positions of the first mirror 13 and the second mirror 17 are positions at which the processing laser beam 11 and the measurement beam 15 pass through the center of the lens 14 .

The lens 14 is a lens for focusing the processing laser beam 11 and the measurement light 15 onto the processing point 20 . The lens 14 is, for example, an fθ lens.

The first mirror 13 and lens 14 constitute a general optical scanning system made up of a galvanomirror and an fθ lens. Therefore, by rotating the first mirror 13 by a predetermined angle from its origin position, it is possible to control the arrival position of the processing laser beam 11 on the processing surface 19 . Hereinafter, the angle by which the first mirror 13 is rotated from its origin position is referred to as "movement amount of the first mirror 13". The amount of movement of the first mirror 13 for irradiating the desired processing point 20 with the processing laser beam 11 depends on the positional relationship between the optical members constituting the processing head 2 and the distance from the lens 14 to the processing surface 19. can be set uniquely.

The distance from the lens 14 to the processing surface 19 is such that the focal position where the processing laser beam 11 is most condensed coincides with the processing surface 19 so that processing by the processing laser beam 11 is most efficiently performed. It is preferable to set the distance as However, it is not limited to this, and the distance from the lens 14 to the processing surface 19 may be determined as an arbitrary distance according to the processing application.

The position of the processing point 20 can be scanned on the processing surface 19 by changing the operation amount of the first mirror 13 according to a predetermined operation schedule. Furthermore, by switching on and off the laser oscillator 5 under the control of the control unit 6, any position on the processing surface 19 within the scannable range of the processing laser beam 11 can be lasered in any pattern. can be processed.

The beam shift mechanism 38 is a mechanism for translating the measurement optical axis 23 of the measurement light 15 in two or more axes. For example, beam shift mechanism 38 is a translation stage. The beam shift mechanism 38 moves in a direction perpendicular to the measurement optical axis 23 of the measurement light 15 when the second mirror 17 is at the origin position (see the xy axis in the figure and the straight double-headed arrow in the figure). It is configured so that it can move in parallel on two or more axes.

The beam shift mechanism 38 is connected to the controller 6 via the third driver 41 and operates under the control of the controller 6 . The third driver 41 operates the beam shift mechanism 38 based on instructions from the controller 6 .

A first lens 39 and a second lens 40 are installed in the beam shift mechanism 38 . The distance between the principal point of the first lens 39 and the principal point of the second lens 40 is set to the sum of the focal lengths of the two lenses.

Also, in this embodiment, the focal length of the first lens 39 and the focal length of the second lens 40 are assumed to be the same.

Further, when the beam shift mechanism 38 is at the origin position and the second mirror 17 is at the origin position, the measurement optical axis 23 of the measurement light 15 is reflected by the dichroic mirror 12 and then the processing light of the processing laser light 11 Axis 24 coincides.

[Influence of Chromatic Aberration]
Next, the influence of chromatic aberration will be described with reference to FIG. FIG. 2 is a diagram schematically showing the laser processing apparatus 1 in a state where the first mirror 13 is moved from the origin position. In FIG. 2, it is assumed that the second mirror 17 is at the origin position.

As shown in FIG. 2, the processing laser beam 11 and the measurement beam 15 reflected by the first mirror 13 travel on the same optical axis until reaching the lens 14 . However, after passing through the lens 14 , there is a deviation in the traveling direction of the processing laser beam 11 and the measuring beam 15 . That is, as shown in FIG. 2, the processing optical axis 24a, which is the optical axis of the processing laser beam 11, and the measurement optical axis 23a, which is the optical axis of the measurement light 15, are deviated. Therefore, the measurement light 15 reaches a position different from the processing point 20 .

This is due to the chromatic aberration of lens 14 . Chromatic aberration is an aberration that occurs because general optical materials including the lens 14 have different refractive indices depending on the wavelength of light.

There are two types of chromatic aberration: longitudinal chromatic aberration and lateral chromatic aberration. Axial chromatic aberration refers to the property that the focal position of a lens differs depending on the wavelength of light. On the other hand, the chromatic aberration of magnification refers to the property that the image height on the focal plane differs depending on the wavelength of light. The deviation in the direction of travel between the processing laser light 11 (processing optical axis 24a) and the measurement light 15 (measurement optical axis 23a) after passing through the lens 14 shown in FIG. 2 is due to chromatic aberration of magnification.

In addition, in the laser processing apparatus 1 of the present embodiment, longitudinal chromatic aberration also occurs at the same time. However, as for the deviation between the processing laser beam 11 and the measuring beam 15 due to axial chromatic aberration, the distance between the collimating lens 16 and the measuring beam inlet 9 is adjusted, and the measuring beam 15 immediately after passing through the collimating lens 16 is converted into a parallel beam. It is possible to deal with it by making the state slightly diverge or converge.

In FIG. 2 , the position where the measuring beam 15 reaches the processing surface 19 is farther than the position where the processing laser beam 11 reaches the processing surface 19 when viewed from the processing origin 26 . However, this is only an example, and depending on the lens configuration of the lens 14 and the magnitude relationship between the wavelengths of the processing laser light 11 and the measurement light 15, the measurement light 15 is closer to the processing origin 26 than the processing laser light 11. may be reached. In general, longer wavelength light reaches a position farther from the processing origin 26 .

As a method of correcting the chromatic aberration of magnification, for example, there is a method of giving the lens 14 the property of an achromatic lens. However, if the lens 14 is to have both the properties of an f-theta lens and the properties of an achromatic lens, a very advanced optical design technique is required, and the design of the lens 14 requires a great deal of time and cost. It hangs. Therefore, in the present embodiment, as described below, the second mirror 17 is operated to correct the chromatic aberration of magnification at low cost.

[Method for correcting lateral chromatic aberration]
Next, a method for correcting chromatic aberration of magnification will be described with reference to FIG. FIG. 3 is a diagram schematically showing the laser processing apparatus 1 in a state in which deviations in the arrival positions of the processing laser light 11 and the measurement light 15 due to chromatic aberration of magnification are corrected.

In FIG. 3, the second mirror 17 is moved from the origin position by a predetermined movement amount (which may also be referred to as a movement angle). As a result, as shown in FIG. 3, the processing optical axis 24 of the processing laser beam 11 and the measurement optical axis 23 of the measurement light 15 are not coaxial between the dichroic mirror 12 and the lens 14 . However, the processing laser light 11 and the measurement light 15 reach the same position on the processing surface 19, that is, the processing point 20, after passing through the lens 14 respectively.

In FIG. 3, the processing optical axis 24a of the processing laser beam 11 passes through the same position as the processing optical axis 24a shown in FIG. On the other hand, in FIG. 3, the measurement optical axis 23b of the measurement light 15 corrected by the operation of the second mirror 17 passes through a position different from the measurement optical axis 23a shown in FIG.

The amount of movement of the second mirror 17 (that is, the angle by which the second mirror 17 is rotated from its origin position) is associated one-to-one with the amount of movement of the first mirror 13 . Since the amount of movement of the first mirror 13 is uniquely determined by the position of the processing point 20 irradiated with the processing laser beam 11 (and the measurement light 15), the amount of movement of the second mirror 17 is also determined by the irradiation of the measurement light 15. It is uniquely determined by the position of the processing point 20 to be processed. In the following description, the amount of movement of the second mirror 17 is referred to as a "correction angle", and how to obtain the correction angle will be described.

[Relationship Between Correction Angle and Scanning Angle]
Next, the relationship between the correction angle and the scanning angle will be explained. In the lens 14 which is an fθ lens, let f be the focal length of the lens 14, let θ be the angle of the light incident on the lens 14 from the lens optical axis 25, and let θ be the distance from the optical axis on the image plane of the light transmitted through the lens 14. (hereinafter referred to as image height) is h, the relationship h=f.theta.

As described above, the first mirror 13 has two rotational axes. Assuming that these two axes are the x-axis and the y-axis, the angle of the x-axis component from the lens optical axis 25 of the light reflected by the first mirror 13 is θx, and the angle of the y-axis component from the lens optical axis 25 is θx. θy. When the image heights in the x direction and the y direction on the image plane are respectively x and y, the relationships x=fθx and y=fθy are established.

Therefore, when the position of the processing point where the processing laser beam 11 reaches the processing surface 19 is (x, y), (x, y)=(fθx, fθy). Also, when the light is incident on the mirror, the emission angle of the reflected light from the mirror changes by a double angular amount. Therefore, when the amount of movement of the first mirror 13 is (φx, φy), the relationship (2φx, 2φy)=(θx, θy) holds. In the following description, the amount of movement (φx, φy) of the first mirror 13 is referred to as "scanning angle".

As described above, in the laser processing apparatus 1 of the present embodiment, when the scanning angle (φx, φy) of the first mirror 13 is determined, the arrival position of the processing laser beam 11 on the processing surface 19, that is, the processing point 20 The position (x,y) of is also determined.

As described above, the scanning angle is uniquely determined by the position of the processing point 20, and similarly the correction amount is also uniquely determined by the position of the processing point 20. FIG. That is, the relationship between the scanning angle and the correction amount is calculated in advance for each position of a certain processing point 20, and the second mirror 17 is operated by the correction amount corresponding to the position of the processing point 20 during processing. It is possible to correct the deviation of the measurement light 15 due to the chromatic aberration of magnification.

[Influence of keyhole angle]
On the other hand, as shown in FIG. 3, even in a state in which the displacement of the respective arrival positions of the processing laser light 11 and the measurement light 15 due to the chromatic aberration of magnification is corrected, the processing optical axis 24a of the processing laser light 11 and the measurement The measurement optical axis 23b of the light 15 does not coincide.

When the scanning speed of the processing laser beam 11 (hereinafter referred to as processing speed) is slow, the forming direction of the keyhole 22 coincides with the processing optical axis 24a of the processing laser beam 11. is obliquely incident with respect to the formation direction of . As a result, the measurement light 15 may not reach the bottom of the keyhole 22 . As a result, the measurement accuracy of the depth of the keyhole 22 deteriorates.

FIG. 4 schematically shows an example of how the keyhole 22 is formed when the processing speed is high. When the processing optical axis 24a of the processing laser beam 11 moves in the positive direction of the x-axis, the keyhole 22 is formed so that the keyhole forming axis 42 of the processing point 20 is the starting point in the processing direction (positive direction of the x-axis). formed with a tilt toward For this reason, there are cases where the measurement light 15 cannot reach the bottom of the keyhole 22 even when the displacement of the arrival positions of the processing laser light 11 and the measurement light 15 due to the chromatic aberration of magnification is corrected. As a result, the measurement accuracy of the depth of the keyhole 22 deteriorates.

In particular, when the beam mode of the laser oscillator 5 is single mode, the spot diameter of the processing laser beam 11 at the processing point 20 is small, for example, 50 μm or less. Therefore, the diameter of the generated keyhole 22 is also reduced, and the deviation between the angle of the keyhole forming axis 42 of the keyhole 22 and the angle of the measurement optical axis 23b of the measurement light 15 affects the measurement accuracy of the depth of the keyhole 22. It is a factor that makes it worse.

Therefore, in the present embodiment, as described below, the beam shift mechanism 38 is operated to correct the angle of the measurement optical axis 23b of the measurement light 15, so that the measurement optical axis 23b and the keyhole forming axis 42 are aligned. to match.

[How to correct the angle of the measurement optical axis]
Next, a method for correcting the angle of the measurement optical axis will be described with reference to FIG. FIG. 5 is a diagram schematically showing the laser processing apparatus 1 in a state in which angular deviations of the keyhole forming axis 42 and the measurement optical axis 23b of the measurement light 15 shown in FIG. 3 are corrected.

In FIG. 5, the beam shift mechanism 38 is moved from the origin position by a predetermined amount of movement (which may be called a movement distance). As a result, the measuring optical axis 23 of the measuring light 15 shifts parallel to the processing optical axis 24 of the processing laser light 11 from the dichroic mirror 12 to the lens 14 . However, the processing laser light 11 and the measurement light 15 reach the same processing point 20 on the processing surface 19 after passing through the lens 14 .

In FIG. 5, the processing optical axis 24a of the processing laser beam 11 passes through the same position as the processing optical axis 24a shown in FIG. 5, the measurement optical axis 23c is obtained by correcting the measurement optical axis 23b shown in FIG. 3 by the operation of the beam shift mechanism . The angle of the measurement optical axis 23c shown in FIG. 5 matches the angle of the keyhole forming axis 42 of the keyhole 22, unlike the angle of the measurement optical axis 23b shown in FIG.

A predetermined movement amount (hereinafter referred to as a correction movement amount) for moving the beam shift mechanism 38 from the origin position is associated with the movement amount and the processing speed of the first mirror 13 . Since the movement amount and processing speed of the first mirror 13 are uniquely determined by the position of the processing point 20 irradiated with the processing laser beam 11 (and the measurement light 15), the correction movement amount is also determined according to the irradiation of the measurement light 15. It is uniquely determined by the position of the processing point 20 . That is, the relationship between the scanning angle and the correction movement amount is calculated in advance for each position of the processing point 20, and the beam shift mechanism 38 is operated by the correction movement amount corresponding to the position of the processing point 20 during processing. , the angular deviation between the keyhole forming axis 42 and the measuring optical axis 23b shown in FIG. 3 can be corrected.

[Method of Creating First Correction Table Data]
A method for creating the first correction formula table data will be described. The first correction mathematical table data is data indicating the correspondence relationship between the scanning angle and the correction angle for each processing point 20 . The first correction mathematical table data may be said to be correction mathematical table data of correction angles.

First, trajectories of the processing laser beam 11 and the measurement beam 15 on the processing surface 19 will be described with reference to FIG. FIG. 6 shows the processing on the processing surface 19 when only the first mirror 13 is operated without operating the second mirror 17 to scan the surface of the workpiece 18 (that is, the processing surface 19) in a grid pattern. FIG. 2 is a diagram schematically showing trajectories of laser light 11 for measurement and measurement light 15. FIG. FIG. 6 shows a state in which the processed surface 19 is viewed from the lens 14 side.

In FIG. 6, a processing light trajectory 28, which is the trajectory of the processing laser beam 11, is indicated by a solid line, and a measuring light trajectory 27, which is the trajectory of the measuring light 15, is indicated by a dotted line. In the example shown in FIG. 6, since the second mirror 17 is not operating, correction of chromatic aberration of magnification is not performed. Therefore, although the trajectories of the processing laser beam 11 and the measurement light 15 match each other near the processing origin 26 , the deviation between the two increases as the distance from the processing origin 26 increases. As a result, the processing light trajectory 28 draws a grid-like pattern without distortion, while the measurement light trajectory 27 draws a distorted pincushion-shaped trajectory. Note that the shape of the measurement light locus 27 shown in FIG. 6 is an example, and the distortion shape of the measurement light locus 27 may change depending on the optical characteristics of the lens 14 .

Similarly, the amount of positional deviation corresponding to each of the processing light locus 28 and the measurement light locus 27 also depends on the optical characteristics and optical design of the lens 14 . As a general example, in a commercially available fθ lens having a focal length of 250 mm and a processed surface area with a diameter of about 200 mm, a deviation of 0.2 mm to 0.4 mm occurs near the outermost periphery of the processed surface area.

On the other hand, the diameter of the keyhole 22 (see, for example, FIG. 1) generated by irradiating the processing laser beam 11 to the processing point 20 is approximately 0, although it depends on the power and quality of the processing laser beam. .03mm to 0.2mm. As a result, the measurement light 15 does not reach the bottom surface of the keyhole 22 due to the positional deviation between the processing laser light 11 and the measurement light 15 caused by the chromatic aberration of the lens 14, making it impossible to measure the correct penetration depth.

Note that FIG. 6 illustrates a grid pattern of 4×4 squares at regular intervals as an example, but the present disclosure is not limited to this. The grid-like pattern for scanning may be set to a grid with a finer number of cells, or the grid spacing may be narrowed in a region that particularly requires precision in relation to the chromatic aberration of magnification characteristic of the fθ lens. Also, a radial lattice pattern may be set. However, in this embodiment, since the correction angle is set along the two axes of the x-axis and the y-axis, the orthogonal lattice pattern shown in FIG. 6 is more suitable.

Comparing the processing light trajectory 28 and the measurement light trajectory 27 shown in FIG. 6 reveals that there is a deviation at each corresponding grid point of the grid pattern.

In order to create the correction formula data, correction is made so that the processing light grid point 30, which is one grid point on the processing light locus 28, and the corresponding measurement light grid point 29 on the measurement light locus 27 match. Amount needs to be determined.

Next, the flow of the method for creating the first correction formula table data will be described.

First, with reference to FIG. 7, a first example of a method for creating first correction formula table data will be described. FIG. 7 is a flow chart showing a first example of a method for creating the first correction formula table data.

In step S<b>1 , the control unit 6 sets a lattice pattern (for example, the processing light trajectory 28 shown in FIG. 6 ), which is the range of laser processing, on the processing surface 19 of the workpiece 18 . Also, the control unit 6 selects one lattice point from among the plurality of lattice points included in the lattice pattern.

At step S2, the control unit 6 installs a two-dimensional beam profiler (not shown) at the selected grid point. At this time, the height position of the detection surface of the two-dimensional beam profiler is set so as to match the processing surface 19 .

In step S3, the controller 6 sets the scanning angle of the first mirror 13 so that the processing laser beam 11 reaches the selected grid point.

In step S4, the control unit 6 irradiates the processing laser beam 11, and uses a two-dimensional beam profiler to determine the position where the processing laser beam 11 actually reaches the processing surface 19 (hereinafter referred to as the position of the processing laser beam 11). (referred to as the arrival position).

In step S5, the control unit 6 irradiates the measurement light 15, and uses the two-dimensional beam profiler to obtain the position where the measurement light 15 actually reaches the processing surface 19 (hereinafter referred to as the arrival position of the measurement light 15). .

In step S6, the controller 6 adjusts the correction angle of the second mirror 17 while referring to the measurement result of the two-dimensional beam profiler so that the arrival position of the processing laser beam 11 and the arrival position of the measurement light 15 match. set.

In step S7, the controller 6 stores the scanning angle set in step S3 and the correction angle set in step S6 in the memory 31 as correction formula table data.

In step S8, the control section 6 determines whether or not the correction formula table data has been saved at all grid points of the grid pattern. If the correction formula table data has been saved at all grid points (step S8: YES), the flow ends. On the other hand, if correction formula table data has not been saved at all grid points (step S8: NO), the flow proceeds to step S9.

In step S9, the control unit 6 selects one new grid point (that is, a grid point for which correction formula table data has not been saved). After that, the flow returns to step S2.

The first example of the method for creating the first correction table data has been described above.

Next, with reference to FIG. 8, a second example of the method for creating the first correction formula table data will be described. FIG. 8 is a flow chart showing a second example of the method of creating the first correction formula table data.

In this example, for example, a metal flat plate (hereinafter referred to as a metal plate) is used as the temporary workpiece.

In step S11, the control unit 6 sets a grid pattern (for example, the processing light trajectory 28 shown in FIG. 6), which is the range of laser processing, on the processing surface 19 of the metal plate. Also, the control unit 6 selects one lattice point from among the plurality of lattice points included in the lattice pattern.

In step S12, the controller 6 sets the scanning angle of the first mirror 13 so that the processing laser beam 11 reaches the selected grid point.

In step S13, the control unit 6 irradiates the selected grid points with the processing laser beam 11 to form micro holes in the surface of the metal plate. At this time, the output intensity and irradiation time of the processing laser beam 11 are adjusted so as not to penetrate the metal plate. Also, the diameter of the microholes formed here is preferably about two to three times as large as the measurement resolution of the optical interferometer 3 .

In step S14, the controller 6 causes the optical interferometer 3 to measure the shape of the formed minute hole. At this time, by moving the second mirror 17 from the origin position to some extent and scanning the measurement light 15, the three-dimensional shape in the vicinity of the minute hole can be measured.

In step S15, the control unit 6 uses the data indicating the result of the measurement in step S14 to determine the corrected angle of the second mirror 17 that allows the measurement light 15 to reach the deepest part of the minute hole.

In step S16, the controller 6 stores the scanning angle set in step S12 and the correction angle obtained in step S15 in the memory 31 as correction formula table data.

In step S17, the control unit 6 determines whether or not the correction formula table data has been saved at all grid points of the grid pattern. If the correction formula table data has been saved at all grid points (step S17: YES), the flow ends. On the other hand, if correction formula table data has not been saved at all grid points (step S17: NO), the flow proceeds to step S18.

In step S18, the control unit 6 selects one new grid point (that is, a grid point for which correction formula table data has not been saved). After that, the flow returns to step S12.

The second example of the method for creating the first correction table data has been described above.

The first correction table data is obtained by the first example or the second example described above. If the lattice pattern set in step S1 or step S11 is the 4×4 lattice pattern shown in FIG. 6, only 16 lattice points can be used to create correction mathematical table data. Therefore, it is preferable to create more correction table data by setting a lattice pattern including 16 or more lattice points.

However, even if many correction formula table data are created, the scanning angle of the first mirror 13 can be set to any value as long as it is within the mechanical operating range. may not match. In such a case, it is necessary to obtain the correction angle by interpolating the correction mathematical table data. A method of interpolating this correction formula table data to obtain a correction angle will be described later.

[Method of Creating Second Correction Table Data]
A method of creating the second correction formula table data will be described. The second correction mathematical table data is data indicating the correspondence relationship between the scanning angle and the correction movement amount. As described above, the correction movement amount corresponds to the position of the machining point 20 (hereinafter referred to as machining position) and machining speed.

The creation of the second correction mathematical table data is performed after the creation of the first correction mathematical table data described above. Also, the second correction mathematical table data is created separately for the machining position and the machining speed. Hereinafter, the corrected movement amount regarding the machining position will be referred to as "position correction movement amount", and the correction movement amount regarding the machining speed will be referred to as "speed correction movement amount". In this embodiment, as the second correction mathematical table data, the correction mathematical table data for the position correction movement amount and the correction mathematical table data for the speed correction movement amount are created.

First, with reference to FIG. 9, the flow of the method for creating correction mathematical table data for the amount of position correction movement will be described. FIG. 9 is a flow chart for explaining an example of a method for creating correction mathematical table data for position correction movement amounts.

In this example, for example, a metal flat plate (hereinafter referred to as a metal plate) is used as the temporary workpiece.

In step S21, the control unit 6 sets a lattice pattern (for example, the processing light trajectory 28 shown in FIG. 6), which is the range of laser processing, on the processing surface 19 of the metal plate. Also, the control unit 6 selects one lattice point from among the plurality of lattice points included in the lattice pattern.

In step S22, the controller 6 sets the scanning angle of the first mirror 13 so that the processing laser beam 11 reaches the selected grid point.

In step S23, the controller 6 sets the correction angle of the second mirror 17 so that the measurement light 15 reaches the selected grid point. The correction angle here is a value stored as the above-described first correction mathematical table data.

In step S24, the control unit 6 irradiates the selected lattice points with the processing laser beam 11 to form minute holes in the surface of the metal plate. At this time, the output intensity and irradiation time of the processing laser beam 11 are adjusted so as not to penetrate the metal plate. Also, the diameter of the microholes formed here is preferably about two to three times as large as the measurement resolution of the optical interferometer 3 .

In step S25, the control unit 6 causes the beam shift mechanism 38 to scan the angle of the measurement optical axis 23, and obtains the position correction movement amount that maximizes the measured value of the depth of the keyhole 22. FIG.

In step S26, the control unit 6 stores the scanning angle set in step S22 and the position correction movement amount obtained in step S25 in the memory 31 as correction mathematical table data.

In step S27, the control unit 6 determines whether or not the correction formula table data has been saved at all grid points of the grid pattern. If the correction formula table data has been saved at all grid points (step S27: YES), the flow ends. On the other hand, if correction formula table data has not been saved at all grid points (step S27: NO), the flow proceeds to step S28.

In step S28, the control unit 6 selects one new grid point (that is, a grid point for which correction formula table data has not been saved). After that, the flow returns to step S22.

By the method described above, the correction mathematical table data of the position correction movement amount is obtained. Note that the lattice pattern set in step S21 is the same as the lattice pattern set in the above-described method for creating the first correction formula table data. Therefore, when the scanning angle does not match the correction mathematical table data, the correction mathematical table data is interpolated by the same method as described in the first correction mathematical table data creation method to obtain the position correction movement amount. be able to.

Further, in the present embodiment, the correction mathematical table data of the position correction movement amount and the first correction mathematical table data (correction numerical table data of the correction angle) are combined and set as the correction mathematical table of the machining position. .

Next, with reference to FIG. 10, the flow of the method for creating the correction formula table data for the speed correction movement amount will be described. FIG. 10 is a flowchart for explaining an example of a method for creating correction mathematical table data for position correction movement amounts.

In this example, a metal plate is used as the temporary workpiece.

In step S31, the controller 6 sets the scanning angle of the first mirror and the correction angle of the second mirror passing through the scanning line including the processing origin 26 (see FIGS. 2 and 3). For example, a line on the x-axis passing through the processing origin 26 is used as the scanning line, and the values stored as the first correction mathematical table data are used as the scanning angle and the correction angle.

In step S32, the control unit 6 sets the range of machining speed. For example, the control unit 6 sets the machining speed range from the maximum value to the minimum value of the machining speed included in the machining data for machining the workpiece 18 .

In step S33, the control section 6 sets the range of the correction movement amount. For example, the control unit 6 sets a range in which the angle of the measurement optical axis 23 of the measurement light 15 incident on the processing point 20 is ±10 degrees in the scanning direction as the range of the correction movement amount.

In step S34, the controller 6 sets the initial value of the machining speed. For example, as the initial value of the machining speed, the minimum value of the machining speed range is set.

In step S35, the controller 6 sets the initial value of the correction movement amount. For example, as the initial value of the amount of correction movement, the minimum value of the range of the amount of correction movement is set.

In step S36, the control unit 6 simultaneously scans the scanning line with the processing laser beam 11 and the measurement light 15 at the set processing speed, and measures the depth of the keyhole 22. FIG.

In step S37, the control unit 6 records the depth of the keyhole 22 at the position of the machining origin 26 among the depths of the keyhole 22 measured in step S36.

In step S38, the control unit 6 determines whether data corresponding to all values included in the range of the correction movement amount set in step S33 have been acquired. The data here is data indicating the depth of the keyhole 22 at the position of the machining origin 26 .

If data corresponding to all values in the range of the correction movement amount have been acquired (step S38: YES), the flow proceeds to step S310. On the other hand, if data corresponding to all values in the range of the correction movement amount have not been acquired (step S38: NO), the flow proceeds to step S39.

In step S39, the controller 6 sets another correction movement amount. After that, the flow returns to step S36.

In step S310, the control unit 6 obtains the correction movement amount that maximizes the depth of the keyhole 22 based on the depth of the keyhole 22 recorded in step S37.

In step S311, the control unit 6 stores the current machining speed and the correction movement amount that maximizes the depth of the keyhole 22 obtained in step S310 in the memory 31 as correction mathematical table data for the speed correction movement amount. do.

In step S312, the control unit 6 determines whether or not data corresponding to all values within the machining speed range set in step S32 have been obtained. The data referred to here is correction numerical table data indicating the current machining speed and the correction movement amount that maximizes the depth of the keyhole 22 .

If the data corresponding to all the values included in the machining speed range have been obtained (step S312: YES), the flow ends. On the other hand, if data corresponding to all values included in the machining speed range have not been acquired (step S312: NO), the flow proceeds to step S313.

In step S313, the controller 6 sets another machining speed. After that, the flow returns to step S35.

By the method described above, the correction formula table data of the speed correction movement amount is obtained.

FIG. 11 shows an example of correction mathematical table data of the speed correction movement amount. As shown in FIG. 11, in the correction mathematical table data of the speed correction movement amount, the machining speed V _k and the m speed correction movement amount |D _Vk | are associated with each other. In FIG. 11, the velocity correction movement amount |D _Vk | is recorded as the magnitude of the tilt in the scanning direction.

In this embodiment, the correction formula table data for the speed correction movement amount shown in FIG. 11 is used as the correction formula table for the machining speed (see FIG. 17 described later).

[How to create processing data]
Next, a method of creating machining data for machining the workpiece 18 will be described.

Conventionally, in a laser processing apparatus having an fθ lens and a galvanomirror, a plurality of processing data set in time series (for example, an output instruction value to a laser oscillator, a scanning angle, and a processing speed data item) are set by a control unit. A set of data for each processing point) was used to control the laser oscillator and galvanomirror. As a result, each machining point on the surface of the workpiece is machined in time series.

In the present embodiment, data items of the processing data used by the laser processing apparatus 1 include an output instruction value to the laser oscillator 5 (also referred to as laser output data), the position of the processing point 20 (also referred to as the processing point position), and the processing speed. , a scanning angle, a correction angle, and a correction movement amount are added. In the following description, the processing data to which the corrected angle and the corrected movement amount are added as data items in this way will be referred to as "corrected processing data".

Here, an example of corrected processed data will be described with reference to FIG. 12 . FIG. 12 is a diagram showing an example of the configuration of corrected processing data.

As shown in FIG. 12, the corrected machining data includes data number k, laser output data Lk, machining point position _xk , machining point position _yk , machining speed _Vk , scanning angle _φxk as a set of data items. , scanning angle φy _k , correction angle φx _k , correction angle φy _k , correction movement amount Dx _k , and correction movement amount Dy _k .

The data number k indicates the order of processed data. Laser output data _Lk indicates an output instruction value to the laser oscillator 5 . The machining point position _xk indicates the position of the machining point 20 in the x direction. The machining point position _yk indicates the position of the machining point 20 in the y direction. The processing speed _Vk indicates the scanning speed of the processing laser beam 11 . A scanning angle _φxk indicates a scanning angle of the first mirror 13 that performs scanning in the x direction. A scanning angle _φyk indicates a scanning angle of the first mirror 13 that performs scanning in the y direction. The correction angle ψx _k indicates the correction angle of the second mirror 17 responsible for correcting the position of the measuring beam 15 in the x direction. The correction angle _ψyk indicates the correction angle of the second mirror 17 responsible for correcting the position of the measuring beam 15 in the y direction.

In FIG. 12, the suffix k attached to each data item other than the data number k indicates that it is the data item corresponding to the data number k-th. The scanning angle in the corrected processed data is an example of the "first indicated value". Also, the corrected angle in the corrected processed data is an example of the "second indicated value". Further, the corrected movement amount in the corrected processed data is an example of the "third indicated value".

An example of corrected processed data has been described above.

Next, with reference to FIG. 13, the flow of the process data creation method will be described. FIG. 13 is a flow chart showing a method of creating processing data.

In step S41, the control section 6 sets the data number k to be referred to to zero. A data number k is assigned to an area in the memory 31 in which processed data is stored.

In step S42, the control unit 6 sets the laser output data L _k , the processing point positions x _k , y _k , and the processing speed V _k in the area of the data number k in the memory 31 (which may be called a memory location). (You can say save). These values are set values set by the user of the laser processing apparatus 1 using an operation unit (for example, keyboard, mouse, touch panel, etc.) (not shown) in order to achieve desired laser processing.

In step S43, _the control unit 6 calculates the scanning angles φxk, _φyk of the first mirror 13 based on the processing point positions _xk , _yk set in step S42, and calculates the scanning angles _φxk , _φyk as It is saved in the area of data number k in the memory 31 . When the focal length of the lens 14 is f, there is a relation of (x _k , y _k )=(2f·φx _k , 2f·φy _k ) between the processing point position and the scanning angle. The scan angle is automatically determined from It should be noted that the relational expression between the processing point position and the scanning angle, the correspondence table, and the like may be set in advance by the user. In that case, the control unit 6 may determine the scanning angles φx _k and φy _k of the first mirror 13 using the processing point position, the scanning angle relational expression, the correspondence table, or the like.

In step S44, the control unit 6 determines whether or not setting of processing data has been completed for all data numbers k. If the processing data setting is completed for all data numbers k (step S44: YES), the flow ends. On the other hand, if setting of processing data has not been completed for all data numbers k (step S44: NO), the flow proceeds to step S45.

In step S45, the data number k to be referred to is incremented by one. After that, the flow returns to step S42.

Through the above flow, processing data is set for all data numbers k.

[How to set the correction angle]
Next, a method of setting a correction angle for each machining point position for each machining data set according to the flow of FIG. 13 will be described.

First, with reference to FIG. 14, the configuration of correction mathematical table data for machining positions will be described. FIG. 14 is a diagram showing a processing position correction formula table 34 schematically showing the configuration of processing position correction formula table data.

FIG. 14 schematically shows corrected machining data set for each lattice point on the machining surface 19 as data points 32 . Data points 32, which are corrected machining data, each include a position on machining surface 19 (that is, a machining point position), a scanning angle, a correction angle, and a position correction movement amount, as described above. A correction data point 33 is a point corresponding to the processing origin 26 on the processing surface 19 .

In the following description, the position of each data point 32 in the processing position correction table 34 is indicated by scanning angles (φx, φy) for convenience. Let i be the data number in the direction corresponding to the scanning angle φx, and let j be the data number in the direction corresponding to the scanning angle φy. Each data point 32 corresponds to a correction formula table scanning angle (Φx _i , Φy _j ), a correction formula table correction angle (Ψx _ij , Ψy _ij ), and a correction formula table position correction movement amount (Dpx _ij , Dpy _ij ) and (Φx _i , Φy _j , ψx _ij , ψy _ij , Dpx _ij , Dpy _ij ). The scan angles (Φx _i , Φy _j ) for the correction formula table have elements of the scan angles (φx, φy).

Next, the flow of the correction angle setting method will be described with reference to FIG. FIG. 15 is a flow chart showing a method of setting the correction angle.

In step S51, the control section 6 sets the data number k to be referred to to zero.

In step S52, the control unit 6 determines the scanning angles (φx _k , φy _k ) stored in the area of data number k in the memory 31 and all the correction table scans in the processing position correction table 34. The angles (Φx _i , Φy _j ) are compared to determine whether or not there are data numbers i and j where Φx _k =Φx _i and Φy _k =Φy _j . In this step S52, the control unit 6 determines whether or not there is a data item including a scanning angle that is exactly the same as the scanning angle set by the user in the processing position correction number table 34 or not.

If there are data numbers i and j satisfying φx _k =Φx _i and φy _k =Φy _j (step S52: YES), the flow proceeds to step S53. On the other hand, if there is no data number i, j satisfying φx _k =Φx _i and φy _k =Φy _j (step S52: NO), the flow proceeds to step S54.

In step S53, the control unit 6 sets the correction angles to (ψx _k , ψy _k )=(ψx _ij , ψy _ij ) using the data numbers i and j where φx _k =Φx _i and Φy _k =Φy _j . set. That is, in step S53, since there is a data item including the scanning angle exactly the same as the scanning angle set by the user, the control unit 6 sets the corresponding correction angle for the correction formula table as the correction angle.

In step S54, the control unit 6 performs interpolation processing using the data of the four closest points surrounding the scanning angle (φx _k , φy _k ) set by the user in the correction formula table 34, and obtains the correction angle (φx _k , ψy _k ). Details of step S54 will be described later.

In step S55, the control unit 6 sets (stores) the correction angles (ψx _k , ψy _k ) set in step S53 or step S54 in the area of the data number k of the processed data in the memory 31 .

In step S<b>56 , the control unit 6 determines whether or not the setting of the correction angle has been completed for all the processing data stored in the memory 31 . If the setting of the correction angle has been completed for all of the processing data (step S56: YES), the flow ends. On the other hand, if setting of the correction angle has not been completed for all of the processing data (step S56: NO), the flow proceeds to step S57.

In step S57, the controller 6 increments the data number k to be referred to by one. After that, the flow returns to step S52.

According to the flow described above, correction angles are set for all data numbers k in the processing data set according to the flow of FIG.

[Details of interpolation processing]
Next, step S54 (interpolation processing) shown in FIG. 15 will be described in detail. The interpolation processing in step S54 is performed when the scanning angles (φx _k , φy _k ) set by the user do not match any of the scanning angles (φx _i , φy _j ) for the correction formula table in the data point 32. done.

FIG. 16 shows that the scanning angle X (φx _k , φy _k ) set by the user as processing data is the scanning angle (φx _i , Φy _j ) and shows the relationship between the scanning angle X (φx _k , φy _k ) and the correction data points around it.

As shown in FIG. 16, the points corresponding to the scanning angles X (φx _k , φy _k , φx _k , φy _k , Dpx _k , Dpy _k ) are the corrected data points A (φx _i , φy _j , ψx _ij , ψy _IJ , DPX _IJ , DPY _IJ ), B (φx _{I + 1} , φy _{J + I + 1J} , ψY _{+ 1J, DPX I + 1J ,} DPY _{I + 1J} ), C (φx _I , _{J J + 1} , ψx _{IJ + 1} , ψY _{IJ + 1} , ψY _{IJ + 1} , DPY _{IJ + 1} ) , D(Φx _i+1 , Φy _j+1 , ψx _i+1j+1 , ψy _i+1j+1 , Dpx _i+1j+1 , Dpy _i+1j+1 ). The relationships Φx _i ≤ _Φxk ≤ Φx _{i +1} (the equality is not established at the same time) and _Φyj ≤ _Φyk ≤ Φyj ₊₁ (the equality are not established at the same time) are established. The correction angle (ψx _k , ψy _k ) at this time is obtained by the following equation (1) using the values of the scanning angle X (φx _k , φy _k ) and the values of the correction data points A, B, C, and D. and obtained by the formula (2).
_ψxk =( _Eψxij +Fψxi _+1j +Gψxij ₊₁ +Hψxi _+1j+1 )/J (1)
_ψyk =( _Eψyij +Fψyi _+1j +Gψyij ₊₁ + _Hψyi+1j+1 )/J (2)

E, F, G, H, and J in formulas (1) and (2) are determined by the following formulas (3) to (7).
E=(φx _k −Φx _i )(φy _k −Φy _j ) (3)
F=(Φx _i+1 −Φx _k )(Φy _k −Φy _j ) (4)
G=(φx _k −Φx _i )(Φy _j+1 −φy _k ) (5)
H=(Φx _i+1 −Φx _k )(Φy _j+1 −Φy _k ) (6)
J=(Φx _i+1 −Φx _i )(Φy _j+1 −Φy _j ) (7)

By the interpolation processing described above, the correction angle can be calculated based on the scanning angle set by the user.

In the interpolation processing described above, the linear interpolation method is used as an example, but other known two-dimensional interpolation methods (spline interpolation, quadratic surface approximation, etc.) may be used. Further, from the correction angles (Ψx _ij , Ψy _ij ) for the correction number table on the correction number table 34 of the processing position, a high-order approximate continuous curved surface for the correction angle with respect to the scanning angle is calculated in advance, and corresponds to the scanning angle. You may make it calculate the correction|amendment angle which carries out.

[Method of setting compensation movement]
Next, a method of setting a correction movement amount for each machining point position for each machining data set according to the flow of FIG. 13 will be described. In the present embodiment, a position correction movement amount and a speed correction movement amount are set as the correction movement amount.

Next, with reference to FIG. 17, the flow of the correction movement amount setting method will be described. FIG. 17 is a flow chart showing a method for correcting the amount of movement.

In step S61, the control section 6 sets the data number k to be referred to to zero.

In step S62, the control unit 6 determines the scanning angles (φx _k , φy _k ) stored in the area of the data number k in the memory 31 and all correction table scans in the processing position correction table 34. The angles (Φx _i , Φy _j ) are compared to determine whether or not there are data numbers i and j where Φx _k =Φx _i and Φy _k =Φy _j . In this step S62, the control unit 6 determines whether or not there is a data item including a scanning angle that is exactly the same as the scanning angle set by the user in the processing position correction number table 34 or not.

If there are data numbers i and j satisfying φx _k =φx _i and φy _k =φy _j (step S62: YES), the flow proceeds to step S63. On the other hand, if there is no data number i, j satisfying φx _k =Φx _i and φy _k =Φy _j (step S62: NO), the flow proceeds to step S64.

In step S63, the control unit 6 uses the data numbers i and j where _φxk = φxi _{and φyk} = _φyj to set the position correction movement amount to ( _Dpxk , _Dpyk ) = ( _Dpxij , _Dpyij ). That is, in step S63, since there is a data item including the scanning angle that is exactly the same as the scanning angle set by the user, the control unit 6 sets the corresponding position correction movement amount for the correction formula table as the position correction movement amount. are doing.

In step S64, the control unit 6 performs interpolation processing using the data of the four closest points surrounding the scanning angle (φx _k , φy _k ) set by the user in the processing position correction numerical table 34, and performs position correction. Set the amount of movement (Dpx _k , Dpy _k ). The interpolation processing in this step S64 can be performed by the same method as the interpolation processing in step S54 of FIG. 15 mentioned above.

In step S65, the control unit 6 sets the speed correction movement amount (Dvx _k , Dvy _k ) from the machining speed V _k using the machining speed correction table.

Specifically, first, the control unit 6 obtains the magnitude Dv of the speed correction movement amount corresponding to the machining speed _Vk from the machining speed correction table shown in FIG. Next, the control unit 6 uses the following equations (8) to (10) to determine the processing point position (x _k , y _k ) of the current data number k and the processing point position (x _k+1 , y _k+1 ) to determine the velocity correction movement amount (Dvx _k , Dvy _k ).
_Dvxk = Dvx(xk ₊₁ - _xk )/R (8)
_Dvyk =Dv×(yk ₊₁ - _yk )/R (9)
R=√((x _k+1 −x _k ) ² +(y _k+1 −y _k ) ² ) (10)

In step S66, using the position correction movement amount and the speed correction movement amount, the control unit 6 sets the correction movement amount ( _Dxk , _Dyk ) to ( _Dxk , _Dyk )=( _Dpxk + _Dvxk , _Dpyk + _Dvyk ).

In step S<b>67 , the control unit 6 sets (stores) the correction movement amount (Dx _k , Dy _k ) set in step S<b>66 in the area of the data number k of the processed data in the memory 31 .

In step S<b>68 , the control unit 6 determines whether or not the setting of the correction movement amount has been completed for all the processing data stored in the memory 31 . When the setting of the correction movement amount is completed for all the processing data (step S68: YES), the flow ends. On the other hand, if setting of the correction movement amount has not been completed for all of the processing data (step S68: NO), the flow proceeds to step S69.

In step S69, the controller 6 increments the data number k to be referred to by one. After that, the flow returns to step S62.

According to the above flow, the correction movement amount is set for all the data numbers k in the processing data set by the flow of FIG.

[Laser processing method]
Next, the flow of the laser processing method by the laser processing apparatus 1 will be described with reference to FIG. 18 . FIG. 18 is a flow chart showing a laser processing method.

In step S71, the control section 6 sets the data number k to be referred to to zero.

In step S72, the control unit 6 generates corrected processing data (laser output data _Lk , scanning angles _φxk , _φyk , correction angles _ψxk , _ψyk , correction movement amounts _Dxk , _Dyk ) corresponding to data number k. ) is read from the memory 31 .

In step S73, the control unit 6 operates the first mirror 13 based on the scanning angles (φx _k , φy _k ), operates the second mirror 17 based on the correction angles (φx _k , φy _k ), and corrects the The beam shift mechanism 38 is operated based on the amount of movement (Dx _k , Dy _k ).

Specifically, the controller 6 notifies the first driver 7 of the scanning angles (φx _k , φy _k ). Thereby, the first driver 7 operates the first mirror 13 based on the scanning angles (φx _k , φy _k ). The control unit 6 also notifies the second driver 8 of the correction angles (ψx _k , ψy _k ). Thereby, the second driver 8 operates the second mirror 17 based on the correction angles (ψx _k , ψy _k ). Also, the control unit 6 notifies the third driver 41 of the correction movement amount (Dx _k , Dy _k ). Thereby, the second driver 8 operates the beam shift mechanism 38 based on the correction movement amount (Dx _k , Dy _k ).

In step S74, the controller 6 transmits the laser output data _Lk as the laser output value to the laser oscillator 5, and causes the laser oscillator 5 to oscillate the processing laser beam 11 based on the laser output data _Lk .

In step S75, the control unit 6 determines whether or not laser processing corresponding to all data numbers k stored in the memory 31 has been completed. If laser processing corresponding to all data numbers k has been completed (step S75: YES), the flow ends. On the other hand, if laser processing corresponding to all data numbers k has not been completed (step S75: NO), the flow proceeds to step S76.

In step S76, the control section 6 increments the data number k to be referred to by one. After that, the flow returns to step S72.

According to the above flow, laser processing is executed for all data numbers k.

[How to measure keyhole depth]
Next, with reference to FIG. 19, the flow of the method for measuring the depth of the keyhole 22 (see, for example, FIG. 1) during execution of the laser processing method described above will be described. FIG. 19 is a flow chart showing a method for measuring the depth of the keyhole 22. As shown in FIG.

In step S81, the control unit 6 acquires position data of the processing surface 19 of the unprocessed workpiece 18 before starting the laser processing method described with reference to FIG. The position data here is data indicating the height of the unmachined surface 19 (in other words, the position of the machined surface 19 in the Z-axis direction shown in FIG. 1 and the like). The control unit 6 also issues a command to start measuring the depth of the keyhole 22 to the measurement processing unit 4 .

When the laser processing method shown in FIG. 18 is started, the measurement processing unit 4 causes the optical interferometer 3 to emit the measurement light 15 in step S82. Then, the measurement processing unit 4 generates an optical interference signal according to the optical path difference between the measurement light 15 reflected and returned from the keyhole 22 and the reference light.

In step S83, the measurement processing unit 4 calculates the depth of the keyhole 22 (that is, penetration depth) using the position data and the optical interference signal. Then, the controller 6 stores data indicating the calculated depth of the keyhole 22 (hereinafter referred to as keyhole depth data) in the memory 31 .

In step S84, the control unit 6 determines whether or not to end the measurement of the depth of the keyhole 22. When ending the measurement (step S84: YES), the flow proceeds to step S85. On the other hand, if the measurement is not finished (step S84: NO), the flow returns to step S82.

In step S85, after the laser processing method shown in FIG. 18 is completed, the control section 6 issues a command to the measurement processing section 4 to end the measurement of the depth of the keyhole 22. FIG.

The command to start measuring the depth of the keyhole 22 and the command to stop measuring the depth of the keyhole 22 may be issued not by the control unit 6 but by the user using an operation unit or the like (not shown). .

[effect]
As described above, the laser processing apparatus 1 of the present embodiment includes the laser oscillator 5 that oscillates the processing laser beam 11 toward the processing point 20 to be processed on the surface (processing surface 19) of the workpiece 18. and an optical interferometer 3 that emits the measurement light 15 to the processing point 20 and generates an optical interference intensity signal based on the interference caused by the optical path difference between the measurement light 15 reflected at the processing point 20 and the reference light; A first mirror 13 that changes the direction of travel of the processing laser beam 11 and the measurement light 15, a second mirror 17 that changes the incident angle of the measurement light 15 to the first mirror 13, and a first mirror 13 for the measurement light 15. a beam shift mechanism 38 that changes the incident position of the laser beam 11 for processing and the measurement beam 15; Machining of the workpiece 18 that has been corrected in advance so as to eliminate deviation on the surface of the workpiece 18 at one reaching position and deviation between the angle of the keyhole 22 occurring at the machining point 20 and the angle of the measurement light 15. a memory 31 for storing corrected processing data for processing, and a controller 6 for controlling the laser oscillator 5, the first mirror 13, the second mirror 17, and the beam shift mechanism 38 based on the corrected processing data. and a measurement processing unit 4 for measuring the depth of the keyhole 22 generated at the processing point by the processing laser beam 11 based on the optical interference intensity signal.

With such a configuration, it is possible to correct the deviation of the arrival positions of the processing laser light 11 and the measurement light 15 on the processing surface 19 after passing through the lens 14 caused by the chromatic aberration of magnification of the lens 14 . In addition, the measurement light is caused by the angle deviation between the processing laser beam 11 and the measurement light 15 on the processing surface 19 after passing through the lens 14 caused by the magnification chromatic aberration of the lens 14, and the change in the keyhole formation state due to the processing speed. Angular deviation from the keyhole forming axis 42 of 15 can be corrected. Thereby, the measurement of the depth of the keyhole 22 by the optical interferometer 3 can be preferably performed. That is, it is possible to accurately measure the depth of the keyhole.

FIG. 20 is a diagram illustrating the trajectories of the processing laser beam 11 and the measurement beam 15 on the processing surface 19 after the influence of the chromatic aberration of magnification is corrected by operating the second mirror 17 . According to FIG. 20, unlike FIG. 6, the processing light trajectory 28, which is the trajectory of the processing laser beam 11, the measurement light trajectory 27, which is the trajectory of the measurement light 15, and each grid point are matched. I understand. Also, at this time, the measurement optical axis 23c (see FIG. 5) of the measurement light 15 and the keyhole forming axis 42 (see FIG. 4) coincide.

It should be noted that the present disclosure is not limited to the description of the above embodiments, and various modifications are possible without departing from the scope of the present disclosure. Modifications will be described below.

[Modification 1]
In the embodiment, the case where the second mirror 17, which is a galvanomirror, is used to change the optical axis direction of the measurement light 15 has been described as an example, but the present disclosure is not limited to this.

The second mirror used in the laser processing apparatus 1 is installed, for example, between the measurement light inlet 9 and the dichroic mirror 12, and can change the optical axis direction of the measurement light 15 based on the control of the controller 6. Any configuration is acceptable.

FIG. 21 shows the second mirror 35 having such a configuration. FIG. 21 is a diagram schematically showing the laser processing apparatus 1 using the second mirror 35. As shown in FIG.

A laser processing apparatus 1 shown in FIG. 21 has a second mirror 35 instead of the second mirror 17 shown in FIG. Note that the laser processing apparatus 1 shown in FIG. 21 does not have the collimating lens 16 shown in FIG. 1 and the like.

A second mirror 35 is a parabolic mirror fixed between the measurement light inlet 9 and the dichroic mirror 12 .

A moving stage 36 is provided at the measurement light introduction port 9 .

The stage driver 37 is electrically connected to the controller 6 and operates the moving stage 36 based on instructions from the controller 6 . As a result, the moving stage 36 moves in the yz direction in the drawing (see the vertical double-headed arrow in the drawing). That is, the moving direction of the moving stage 36 is the biaxial direction perpendicular to the measurement optical axis 23 .

The emission end of the measurement light 15 at the measurement light introduction port 9 is arranged so as to coincide with the focal point of the second mirror 35 . As a result, the measurement light 15 becomes parallel light after being reflected by the second mirror 35 and travels toward the dichroic mirror 12 .

The movement of the moving stage 36 changes the angle of the measurement optical axis 23 from the second mirror 35 toward the dichroic mirror 12 . This provides the same effect as when the second mirror 17, which is a galvanomirror, is used.

The second mirror used in the laser processing apparatus 1 may be a MEMS (Micro Electro Mechanical Systems) mirror or the like.

[Modification 2]
In the embodiment, the case where the focal lengths of the first lens 39 and the second lens 40 installed in the beam shift mechanism 38 are the same has been described as an example, but the present disclosure is not limited to this.

For example, the focal length of the second lens 40 is longer than the focal length of the first lens 39, and the distance between the lens principal points of the first lens 39 and the second lens 40 is the focal length of the first lens 39. The sum with the focal length of the second lens 40 may be used. Such a configuration is commonly referred to as a Keplerian beam expander.

In the configuration described above, the amount by which the measurement optical axis 23 of the measurement light 15 translates is magnified in proportion to the ratio of the focal length of the second lens 40 to the focal length of the first lens 39 . Thereby, the movement range of the beam shift mechanism 38 can be set small. Therefore, a stage driven by a piezo element can be adopted as the translation stage of the beam shift mechanism 38 . Therefore, high-speed and accurate positioning can be achieved.

The configuration described above is also suitable for synchronizing the first mirror 13 and the second mirror 17 . Also, the angle of the measurement optical axis 23 of the measurement light 15 is reduced in inverse proportion to the ratio of the focal length of the second lens 40 to the focal length of the first lens 39 . Therefore, the influence of positioning errors such as temperature drift of the second mirror 17 can be reduced. Therefore, highly accurate positioning can be achieved.

[Modification 3]
In the embodiment, the case where the beam shift mechanism 38 is arranged after the second mirror 17 between the measurement light inlet 9 and the dichroic mirror 12 has been described as an example, but the present disclosure is not limited to this.

For example, the second mirror 17 may be arranged after the beam shift mechanism 38 . However, when the spot diameter of the measurement light 15 at the processing point 20 needs to be set small, the beam diameter of the measurement light 15 entering the lens 14 must be set large. Therefore, when the second mirror 17 is arranged after the beam shift mechanism 38, the size of the second mirror 17 must be increased in accordance with the beam diameter of the measurement light 15, resulting in an increase in the size of the measurement head. A disadvantage may occur.

In order to avoid this disadvantage, for example, a beam shift mechanism 38 is arranged after the second mirror 17 between the measurement light introduction port 9 and the dichroic mirror 12, and the beam expander is configured in the beam shift mechanism 38. It is preferable to With such a configuration, the spot diameter of the measurement light 15 at the processing point 20 can be set small while the size of the second mirror 17 is kept small. Therefore, the depth of the small-diameter keyhole 22 can be measured with high accuracy without increasing the size of the measurement head.

[Modification 4]
In the embodiment, the case where the beam shift mechanism 38, which is a translation stage, is used to translate the measurement optical axis 23 of the measurement light 15 has been described as an example, but the present disclosure is not limited to this.

The beam shift mechanism 38 used in the laser processing apparatus 1 is installed, for example, between the measurement light introduction port 9 and the dichroic mirror 12, and can translate the measurement optical axis 23 based on the control of the control unit 6. Any configuration can be used.

FIG. 22 shows the beam shift mechanism 50 having such a configuration. FIG. 22 is a diagram schematically showing the laser processing apparatus 1 using the beam shift mechanism 50. As shown in FIG.

A laser processing apparatus 1 shown in FIG. 22 has a beam shift mechanism 50 instead of the beam shift mechanism 38 shown in FIG. 1 and the like. A beam shift mechanism 50 is fixed between the measurement light inlet 9 and the dichroic mirror 12 .

The beam shift mechanism 50 has a first parallel plane substrate 43 and a second parallel plane substrate 44 . The first parallel plane substrate 43 and the second parallel plane substrate 44 are made of glass, for example.

In the beam shift mechanism 50, the first plane-parallel substrate 43 and the second plane-parallel substrate 44 are arranged so as to be inclined with respect to the measurement optical axis 23 of the measurement light 15 when the second mirror 17 is at the origin position. ing.

Also, the first parallel plane substrate 43 and the second parallel plane substrate 44 each rotate around the measurement optical axis 23 of the measurement light 15 from the second mirror 17 . The rotational positions (which may also be referred to as rotational angles) of the first parallel plane substrate 43 and the second parallel plane substrate 44 are controlled based on command values from the third driver 41 .

When the measurement light 15 is transmitted through the first parallel plane substrate 43 and the second parallel plane substrate 44, the emitted light is shifted in parallel with respect to the incident light due to refraction of the light. Therefore, the measurement optical axis 23 of the measurement light 15 can be translated to an arbitrary position in the xy direction in the figure according to the combination of the rotational positions of the first parallel plane substrate 43 and the second plane parallel substrate 44. can. Therefore, even when the beam shift mechanism 50 is used, the same effect as when the beam shift mechanism 38 having the first lens 39 and the second lens 40 shown in FIG. 1 and the like is used can be obtained.

The modifications described above may be combined as appropriate.

The laser processing apparatus, laser processing method, and correction data generation method of the present disclosure are useful, for example, in laser processing of automobiles, electronic parts, and the like.

REFERENCE SIGNS LIST 1 laser processing device 2 processing head 3 optical interferometer 4 measurement processing unit 5 laser oscillator 6 control unit 7 first driver 8 second driver 9 measurement light introduction port 10 processing light introduction port 11 processing laser light 12 dichroic mirror 13 first Mirror 14 Lens 15 Measurement Light 16 Collimating Lens 17, 35 Second Mirror 18 Workpiece 19 Processing Surface 20 Processing Point 21 Molten Pool 22 Keyhole 23, 23a, 23b, 23c Measurement Optical Axis 24, 24a Processing Optical Axis 25 Lens Light Axis 26 Processing origin 27 Measurement light trajectory 28 Processing light trajectory 29 Measurement light grid point 30 Processing light grid point 31 Memory 32 Data point 33 Correction data point 34 Processing position correction numerical table 36 Movement stage 37 Stage driver 38, 50 Beam shift mechanism 39 first lens 40 second lens 41 third driver 42 keyhole forming axis 43 first parallel plane substrate 44 second parallel plane substrate

Claims (14)

a laser oscillator that oscillates a processing laser beam to a processing point on the surface of the workpiece;
an optical interferometer that emits measurement light toward the processing point and generates an optical interference intensity signal based on interference caused by an optical path difference between the measurement light reflected at the processing point and the reference light;
a first mirror for changing traveling directions of the processing laser light and the measurement light;
a second mirror that changes the angle of incidence of the measurement light on the first mirror;
a beam shift mechanism that changes the incident position of the measurement light on the first mirror;
a lens that converges the processing laser light and the measurement light onto the processing point;
a memory for storing corrected processing data;
a control unit that controls the laser oscillator, the first mirror, the second mirror, and the beam shift mechanism based on the corrected processing data;
a measurement processing unit that measures the depth of the keyhole generated at the processing point by being irradiated with the processing laser light based on the optical interference intensity signal;
The corrected processing data is
processing data generated in advance for processing the work piece, a shift in the arrival position of at least one of the processing laser light and the measurement light caused by the chromatic aberration of the lens on the surface of the work piece; and Data corrected so as to eliminate the deviation between the angle of the keyhole and the angle of the measurement light,
Laser processing equipment. The corrected processing data is
an output instruction value indicating the intensity of the processing laser beam oscillated from the laser oscillator, a first instruction value indicating the amount of movement of the first mirror, and the second mirror, which are set in advance for each of the processing points; and a third instruction value indicating the amount of operation of the beam shift mechanism,
The laser processing apparatus according to claim 1. wherein the wavelength of the processing laser light and the wavelength of the measurement light are different from each other;
The laser processing apparatus according to claim 1 or 2. The lens is an f-theta lens,
The laser processing apparatus according to any one of claims 1 to 3. The first mirror and the second mirror are each galvanomirrors,
The laser processing apparatus according to any one of claims 1 to 4. The first mirror is a galvanomirror,
the second mirror is a parabolic mirror;
further comprising a moving stage that changes an emission angle of the measurement light from the second mirror;
The laser processing apparatus according to any one of claims 1 to 4. The beam shift mechanism is
A stage that translates along two or more axes in a direction perpendicular to the optical axis of the measurement light when the second mirror is at the origin position,
having a first lens and a second lens;
The laser processing apparatus according to any one of claims 1 to 6. The focal length of the second lens is set longer than the focal length of the first lens,
The second mirror and the beam shift mechanism are arranged such that the measurement light from the optical interferometer passes through the second mirror and the beam shift mechanism in that order.
The laser processing apparatus according to claim 7. The beam shift mechanism is
Having a first parallel plane substrate and a second parallel plane substrate that rotate about the optical axis of the measurement light,
The laser processing apparatus according to any one of claims 1 to 6. A first mirror that changes the traveling direction of the processing laser light and the measurement light, a second mirror that changes the incident angle of the measurement light on the first mirror, and an incident position of the measurement light on the first mirror. A laser processing method performed by a laser processing apparatus having a beam shift mechanism that changes the processing laser light and the measurement light and a lens that converges the processing laser light and the measurement light on a processing point on the surface of the workpiece,
controlling the first mirror, the second mirror, and the beam shift mechanism based on the corrected processing data, and irradiating the workpiece with the processing laser beam and the measurement light;
measuring the depth of a keyhole generated at the processing point by irradiation with the processing laser beam based on interference caused by an optical path difference between the measurement light reflected at the processing point and the reference light;
The corrected processing data is
processing data generated in advance for processing the work piece, a shift in the arrival position of at least one of the processing laser light and the measurement light caused by the chromatic aberration of the lens on the surface of the work piece; and Data corrected so as to eliminate the deviation between the angle of the keyhole and the angle of the measurement light,
Laser processing method. A first mirror that changes the traveling direction of the processing laser light and the measurement light, a second mirror that changes the incident angle of the measurement light on the first mirror, and an incident position of the measurement light on the first mirror. A correction data generation method performed by a laser processing apparatus having a beam shift mechanism that changes the and a lens that converges the processing laser light and the measurement light on the surface of the workpiece,
For processing, the output intensity of the processing laser beam and the operation amount of the first mirror for causing the processing laser beam to reach the processing point are set for each processing point on the surface of the workpiece. generate the data,
calculating a first operation amount, which is an operation amount of the second mirror for causing the measurement light to reach the predetermined position, for each predetermined position on the surface of the workpiece;
calculating, for each processing point, a second movement amount that is the movement amount of the second mirror for causing the measurement light to reach the processing point, based on the first movement amount;
calculating a third operation amount, which is an operation amount of the beam shift mechanism for causing the measurement light to reach the predetermined position, for each predetermined position and processing speed on the surface of the workpiece;
calculating a fourth operation amount, which is an operation amount of the beam shift mechanism for causing the measurement light to reach the processing point, based on the third operation amount;
By adding the second amount of operation and the fourth amount of operation to the data for processing, a shift in the arrival position of at least one of the laser light for processing and the measurement light to the work piece caused by chromatic aberration of the lens. and generating corrected processing data corrected so as to eliminate the deviation between the angle of the keyhole and the angle of the measurement light;
Correction data generation method. In calculating the second movement amount, if the processing point and the predetermined position do not match, interpolation processing is performed using the first movement amount at a predetermined number of the predetermined positions in order of proximity to the processing point, calculating the second amount of motion;
12. The correction data generating method according to claim 11. In calculating the fourth movement amount, if the processing point and the predetermined position do not match, interpolation processing is performed using the third movement amount at a predetermined number of the positions in order of proximity to the processing point. 4 Calculate the amount of movement,
13. The correction data generation method according to claim 11 or 12. The predetermined position is set to a range of the surface of the workpiece corresponding to the movable range of the first mirror, and is set so that the interpolation process can be performed within the range.
14. The correction data generating method according to claim 12 or 13.

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