Focal length specifying device and focal length specifying method

Abstract

To relatively easily specify the focal distance of a laser beam.SOLUTION: A plurality of penetration parts 56 having different outer diameters are formed in the second surface 52 of the workpiece W. A plurality of through parts 56 having an outer diameter equal to or larger than a predetermined threshold are identified. Of the plurality of through parts 56 identified as having a value greater than or equal to the prescribed threshold value, the first through part 57 positioned at one end in the first direction and the second through part 58 positioned at the other end in the first direction are identified. A third through part 59 located at an intermediate position 65 between the first through part 57 and the second through part 58 is specified.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a focal length specifying device and a focal length specifying method. [Background technology]

[0002] Patent Document 1 discloses an optical system position adjustment device that includes a TV camera that captures the light spot diameter of laser light, an image processing device that measures the light spot diameter of the laser light captured by the TV camera and calculates the focal length, and a focus deviation detection sensor that detects the focal length of the focused laser light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-150231 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, to check the focal length of a laser beam, it has been necessary to use a measuring device that can determine the beam shape, such as a focus monitor. However, such measuring devices are relatively expensive, which increases the cost of purchasing the measuring device and the cost of the measurement process.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to make it possible to specify the focal length of laser light relatively easily. [Means for solving the problem]

[0006] A first invention is a focal length determining device that determines the focal length of laser light emitted from a laser head toward a workpiece, the workpiece having a first surface from which the laser light is emitted and a second surface opposite the first surface, wherein a plurality of laser-processed portions are formed on the first surface by emitting the laser light at intervals in a predetermined first direction, and a plurality of through-holes having different outer diameters are formed on the second surface by the laser-processed portions melted to penetrate to the second surface, the focal length determining device comprising: an imaging unit that moves relatively from a predetermined reference position on the second surface in the first direction to image each of the plurality of through-holes; and a calculation unit that calculates the focal length of the laser light, wherein the calculation unit identifies, among the plurality of through-holes imaged by the imaging unit, a plurality of through-holes whose outer diameter is equal to or greater than a predetermined threshold, and, among the plurality of through-holes identified as being equal to or greater than the threshold, identifies a first through-hole located at one end in the first direction and a second through-hole located at the other end in the first direction, and identifies a third through-hole located at an intermediate position between the first through-hole and the second through-hole.

[0007] In the first invention, since it is estimated that the penetration amount of the workpiece is greatest at the third penetration part, the distance from the laser head to the first surface at the third penetration part can be more inexpensively specified as the focal length of the laser light. Also, by checking the multiple penetration parts based on the image captured by the imaging part rather than by the user's visual confirmation, it becomes possible to quantitatively identify the third penetration part.

[0008] The second invention is a focal length determining device of the first invention, further comprising a memory unit that stores a table showing the relationship between the distance from the reference position to the penetration portion and the distance from the laser head at the penetration portion to the first surface, and the calculation unit calculates the distance from the laser head at the third penetration portion to the first surface based on the table stored in the memory unit and the distance from the reference position to the third penetration portion.

[0009] In the second aspect of the present invention, the distance from the laser head to the first surface at the third penetrating portion can be calculated based on the table and the distance from the reference position to the third penetrating portion.

[0010] In this way, by creating a table in advance, the focal length of the laser light can be calculated automatically more quickly and accurately than if the user were to calculate it himself.

[0011] A third aspect of the present invention is the focal length specifying device according to the first or second aspect of the present invention, further comprising a display unit that displays an image of the third penetrating portion.

[0012] In the third invention, an image of the third penetration part can be displayed on the display part, which allows all penetration parts, including the third penetration part, to be imaged by the imaging part and quantitatively measured.

[0013] A fourth aspect of the present invention is the focal length specifying device of the second aspect of the present invention, further comprising a display unit that displays the distance from the laser head to the first surface in the third penetrating portion calculated by the calculation unit.

[0014] In the fourth aspect of the present invention, the distance from the laser head to the first surface in the third penetrating part can be displayed on the display unit, thereby making it possible to display, for example, the calculation result of the focal length of the laser light on the display unit so that it can be seen at a glance.

[0015] A fifth aspect of the present invention is the focal length specifying device according to the first or second aspect of the present invention, wherein the threshold value is smaller than the outer diameter of the through portions located on both end sides in the first direction.

[0016] In the fifth invention, the first through-hole, the second through-hole, and the third through-hole can be identified based on all the through-holes formed on the second surface of the workpiece, and the focal length of the laser light can be determined.

[0017] Specifically, since the amount of heat input of the laser light decreases from the third penetration portion toward both ends in the first direction, the outer diameter of the penetration portion becomes smaller at both ends in the first direction. Therefore, by setting a threshold value for the outer diameter of the penetration portion, it is possible to measure the penetration portion at regular intervals.

[0018] A sixth invention is a focal length determination method for determining the focal length of laser light emitted from a laser head onto a workpiece, the method comprising: a first surface from which the laser light is emitted and a second surface opposite the first surface; a plurality of laser-processed portions formed on the first surface by emitting the laser light at intervals in a predetermined first direction; and a plurality of through-holes having different outer diameters formed on the second surface by the laser-processed portions melted to penetrate to the second surface; an imaging step of relatively moving along the first direction from a predetermined reference position on the second surface to image each of the plurality of through-holes; a step of identifying, from the plurality of through-holes imaged in the imaging step, a plurality of through-holes whose outer diameter is equal to or greater than a predetermined threshold; a step of identifying, from the plurality of through-holes identified as having an outer diameter equal to or greater than the threshold, a first through-hole located at one end side in the first direction and a second through-hole located at the other end side in the first direction; and a step of identifying a third through-hole located at an intermediate position between the first through-hole and the second through-hole.

[0019] In the sixth invention, since it is estimated that the amount of penetration of the workpiece is greatest at the third penetration portion, the distance from the laser head to the first surface at the third penetration portion can be more inexpensively determined as the focal length of the laser light.

[0020] Furthermore, by capturing images of multiple penetration parts, even if the actual focal length of the laser light is unknown, the focal length can be found because at some point the zone is divided into a penetration zone and a non-penetration zone.

[0021] In addition, by periodically checking the calculated focal length, it is possible to manage the conditions for irradiating the workpiece with the laser light (focal length), and if the focus shifts, it is possible to correct the irradiation position of the laser light or perform maintenance on the optical equipment, contributing to the stable operation of the laser processing machine.

[0022] A seventh invention is a focal length determination method according to the sixth invention, further comprising a laser processing step of forming a plurality of the laser-processed portions on the first surface of the workpiece before the imaging step, the laser processing step including: a first step of emitting the laser light from the laser head onto the first surface to form the laser-processed portions; a second step of moving the laser head relative to the workpiece after the first step to a position a first distance away in the first direction and a second distance away in a second direction along the emission direction of the laser light; and a third step of alternately repeating the first step and the second step to form a plurality of the laser-processed portions on the first surface at intervals in the first direction.

[0023] In the seventh invention, by changing the penetration amount of each of the multiple laser-processed portions on the first surface, multiple penetration portions are formed on the second surface near the focal length of the laser light in the workpiece, and the focal length of the laser light can be determined based on the multiple penetration portions.

[0024] Furthermore, since the laser head repeatedly moves an equal distance, it is easy to create a processing program. Also, by changing the movement interval for each laser beam emission, it is possible to flexibly respond to conditions and man-hours, such as performing a check operation with as little error as possible or a rough check operation. [Effects of the Invention]

[0025] According to the present invention, the focal length of laser light can be specified relatively easily. [Brief explanation of the drawings]

[0026] [Figure 1]1 is a schematic diagram showing the configuration of a focal length specifying device according to an embodiment of the present invention. [Figure 2] 10A and 10B are diagrams illustrating the operation of the laser head when forming a laser-machined portion on a first surface of the workpiece. [Figure 3] 3 is a plan view showing a laser-machined portion formed on a first surface of a workpiece. FIG. [Figure 4] 10 is a plan view showing a through-hole formed in a second surface of the workpiece. FIG. [Figure 5] FIG. 10 is a diagram showing a state in which the laser head is moved a first distance in a first direction and a second distance in a second direction. [Figure 6] 10 is a diagram showing a state in which a penetration part having an outer diameter equal to or larger than a predetermined threshold value is identified. FIG. [Figure 7] FIG. 10 is a flowchart showing a procedure for identifying the focal length of laser light. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0028] In each drawing, the X, Y, and Z directions are indicated by arrows, and unless otherwise specified, the following description will be given in accordance with the directions indicated by these arrows.

[0029] <Focal length identification device> As shown in FIG. 1, the focal length specifying device 1 includes a base 5, a moving mechanism 10, an imaging unit 20, and a control unit 30.

[0030] The movement mechanism 10 has a linear guide 11, a mounting plate 12, and a drive unit 13. The linear guide 11 is installed on the base 5. The linear guide 11 extends in the Y direction (the left-right direction in FIG. 1). The linear guide 11 has a mounting plate 12 mounted thereon. The mounting plate 12 is movable in the Y direction along the linear guide 11. A workpiece W is placed on the mounting plate 12.

[0031] The drive unit 13 moves the mounting plate 12 in the Y direction along the linear guide 11. The drive unit 13 is configured, for example, with a motor and a driver (not shown). The drive unit 13 moves the mounting plate 12 based on a control signal from the control unit 30. A signal indicating the movement distance of the mounting plate 12 is sent to the control unit 30.

[0032] The imaging unit 20 is, for example, a camera. The imaging unit 20 is disposed above the workpiece W. The imaging unit 20 moves relative to the workpiece W to capture an image of a through hole 56 in a second surface 52 (described later) of the workpiece W. The imaging data captured by the imaging unit 20 is transmitted to the control unit 30.

[0033] In this embodiment, the position of the imaging unit 20 is fixed and the workpiece W is moved in the Y direction, but for example, the position of the workpiece W may be fixed and the imaging unit 20 may be moved in the Y direction.

[0034] The control unit 30 has a display unit 31, a storage unit 32, and a calculation unit 33. The display unit 31 is configured, for example, by a monitor. The display unit 31 displays images of the workpiece W and the penetration portion 56 captured by the imaging unit 20. Furthermore, the display unit 31 displays the calculation results of the calculation unit 33, which will be described later.

[0035] This allows an image of the third penetration part 59, which will be described later, to be displayed on the display part 31. This allows all of the penetration parts 56, including the third penetration part 59, to be imaged by the imaging part 20 and quantitatively measured.

[0036] Furthermore, as a calculation result of the calculation unit 33 described later, the distance from the laser head 40 to the first surface 51 at the third penetrating portion 59 can be displayed on the display unit 31. This allows, for example, the calculation result of the focal length of the laser light LB to be displayed on the display unit 31 so that it can be seen at a glance.

[0037] The storage unit 32 stores various data. A table 35, which will be described later, is stored in the storage unit 32. The calculation unit 33 calculates the distance from the laser head 40 (see FIG. 2) to a first surface 51 of the workpiece W, and specifies the focal length of the laser light LB. The calculation unit 33 will be described in detail later.

[0038] <Work> As shown in Figures 2 to 4, the workpiece W is made of a plate-like member. The workpiece W has a first surface 51 and a second surface 52. The first surface 51 is a surface from which the laser light LB is emitted from the laser head 40. A plurality of laser-machined portions 55 are formed on the first surface 51 by emitting the laser light LB at intervals in a predetermined first direction (the Y direction in Figure 2).

[0039] The second surface 52 is the surface opposite to the first surface 51. By changing the penetration amounts of the plurality of laser-machined portions 55 on the first surface 51, a plurality of through-holes 56 are formed on the second surface 52 near the focal length of the laser light LB on the workpiece W. The plurality of through-holes 56 are formed by the laser-machined portions 55 that have melted to penetrate to the second surface 52. The plurality of through-holes 56 are melt marks left on the workpiece W after the laser light LB has been irradiated, and have different outer diameters.

[0040] The laser processing step for forming a plurality of laser-machined portions 55 on the first surface 51 of the workpiece W includes a first step, a second step, and a third step. In the first step, laser light LB is emitted from the laser head 40 to the first surface 51 to form the laser-machined portions 55.

[0041] As shown in Figure 5, in the second step, after the first step, the laser head 40 is moved relative to the workpiece W to a position that is a first distance d in the first direction (Y direction in Figure 5) and a second distance h in the second direction (Z direction in Figure 5) along the emission direction of the laser light LB.

[0042] In the third step, the first step and the second step are alternately repeated to form a plurality of laser-machined portions 55 on the first surface 51 at intervals in the first direction.

[0043] 2, the emission start point of the laser light LB is set to a reference position 60. The storage unit 32 stores a table 35 indicating the relationship between a distance D from the reference position 60 to the through-hole 56 and a distance H from the laser head 40 to the first surface 51 at the through-hole 56.

[0044] Specifically, the distance D from the reference position 60 to the through-hole 56 can be calculated as D=n·d, where n is the number of times the laser head 40 is moved in the first direction by the first distance d (n is a natural number).

[0045] Furthermore, the distance H from the laser head 40 to the first surface 51 at the through-hole 56 can be calculated as H=H1+n·h, where n (n is a natural number) is the number of times the laser head 40 is moved the second distance h in the second direction, and H1 is the distance from the laser head 40 to the first surface 51 at the reference position 60.

[0046] As a result, by calculating the distance D from the reference position 60 to the through-hole 56, the distance H from the laser head 40 to the first surface 51 at the through-hole 56 can be calculated.

[0047] Furthermore, by changing the penetration amount of each of the multiple laser processing portions 55 on the first surface 51, multiple penetration portions 56 are formed on the second surface 52 near the focal length of the laser light LB on the workpiece W, and the focal length of the laser light LB can be determined based on the multiple penetration portions 56.

[0048] Furthermore, since the laser head 40 repeatedly moves an equal distance, it is easy to create a processing program. Also, by changing the movement interval for each emission of the laser beam LB, it is possible to flexibly respond to conditions, man-hours, etc., such as performing a checking operation with as little error as possible or a rough checking operation.

[0049] In FIG. 2, the workpiece W is placed on the mounting plate 12 with the second surface 52, on which the multiple through-holes 56 are formed, facing upward. By moving the mounting plate 12 in a first direction (the Y direction in FIG. 2), the imaging position of the imaging unit 20 is moved relative to the workpiece W. This causes a relative movement from a reference position 60 on the second surface 52 along the first direction, thereby performing an imaging step in which each of the multiple through-holes 56 is imaged. Imaging data indicating the multiple through-holes 56 imaged in the imaging step is sent to the control unit 30.

[0050] The calculation unit 33 identifies, from among the plurality of penetration parts 56 imaged by the imaging unit 20, a plurality of penetration parts 56 whose outer diameter is equal to or greater than a predetermined threshold value.

[0051] 6, the display unit 31 displays an image in which the through-holes 56 identified as having an outer diameter equal to or greater than a predetermined threshold are surrounded by a circular identification mark 70. In the example shown in Fig. 6, the calculation unit 33 determines that the outer diameter of the right-most through-hole 56 is less than the threshold, and does not identify it as the through-hole 56 for use in identifying the focal length of the laser light LB, which will be described later.

[0052] Of the multiple penetration portions 56 identified as being above the threshold, the calculation unit 33 identifies a first penetration portion 57 located at one end side in the first direction (left side in Figure 4) and a second penetration portion 58 located at the other end side in the first direction (right side in Figure 4).

[0053] The calculation unit 33 identifies the third penetration portion 59 located at the intermediate position 65 between the first penetration portion 57 and the second penetration portion 58.

[0054] The calculation unit 33 calculates the distance H from the laser head 40 to the first surface 51 at the third penetration portion 59 based on the table 35 stored in the memory unit 32 and the distance D from the reference position 60 to the third penetration portion 59.

[0055] In this way, it is estimated that the penetration amount of the workpiece W is greatest at the third penetration portion 59, and therefore the distance H from the laser head 40 to the first surface 51 at the third penetration portion 59 can be more inexpensively specified as the focal length of the laser light LB. Furthermore, by checking the multiple penetration portions 56 based on the image captured by the imaging unit 20 rather than by the user's visual confirmation, it becomes possible to quantitatively identify the third penetration portion 59.

[0056] Furthermore, the distance from the laser head 40 to the first surface 51 at the third penetrating portion 59 can be calculated based on the table 35 and the distance from the reference position 60 to the third penetrating portion 59.

[0057] In this way, by creating the table 35 in advance, the focal length of the laser light LB can be calculated automatically faster and more accurately than if the user were to calculate it himself.

[0058] 6, the outer diameter of the through-hole 56 located at the other end (the right side in FIG. 6) in the first direction is less than the threshold value, but the present invention is not limited to this. For example, the threshold value may be set to be smaller than the outer diameter of the through-hole 56 located at both ends in the first direction.

[0059] In this way, the first through-hole 57, the second through-hole 58, and the third through-hole 59 can be identified based on all the through-holes 56 formed on the second surface 52 of the workpiece W, and the focal length of the laser light LB can be determined.

[0060] Specifically, the amount of heat input of the laser light LB decreases from the third through portion 59 toward both ends in the first direction, and therefore the outer diameter of the through portion 56 decreases at both ends in the first direction. Therefore, by setting a threshold value for the outer diameter of the through portion 56, it is possible to measure the through portion at regular intervals.

[0061] <Procedure for determining the focal length of laser light> Hereinafter, a procedure for determining the focal length of the laser beam LB will be described with reference to the flowchart of FIG.

[0062] As shown in FIG. 7, in step ST11, a laser beam LB is emitted to the first surface 51 of the workpiece W to form a plurality of laser-machined portions 55, and the process then proceeds to step ST12.

[0063] In step ST12, the imaging unit 20 captures an image of the multiple through holes 56 in the second surface 52 of the workpiece W, and the process proceeds to step ST13.

[0064] In step ST13, it is determined whether the outer diameter of the through portion 56 is equal to or greater than a predetermined threshold value. If the determination in step ST13 is "YES", the process branches to step ST14. If the determination in step ST13 is "NO", the process branches to step ST15.

[0065] In step ST14, the through-holes 56 whose outer diameter is equal to or larger than the threshold value are identified as the through-holes 56 for identifying the focal length of the laser light LB, and the process proceeds to step ST16.

[0066] In step ST15, the through-holes 56 whose outer diameter is less than the threshold value are not specified as the through-holes 56 for specifying the focal length of the laser light LB, and the process proceeds to step ST16.

[0067] In step ST16, it is determined whether all the through-holes 56 have been identified as the through-holes 56 for determining the focal length of the laser light LB. If the determination in step ST16 is "YES", the process branches to step ST17. If the determination in step ST16 is "NO", the process returns to step ST13.

[0068] In step ST17, of the multiple penetration portions 56 identified as being above the threshold, a first penetration portion 57 located at one end side in the first direction (left side in Figure 4) and a second penetration portion 58 located at the other end side in the first direction (right side in Figure 4) are identified, and then step ST18 is proceeded to.

[0069] In step ST18, the third penetration portion 59 located at the intermediate position 65 between the first penetration portion 57 and the second penetration portion 58 is identified, and the process proceeds to step ST19.

[0070] In step ST19, the distance H from the laser head 40 to the first surface 51 at the third penetrating portion 59 is calculated based on the table 35 stored in the memory unit 32 and the distance D from the reference position 60 to the third penetrating portion 59, and is identified as the focal length of the laser light LB, and the processing is terminated.

[0071] In this way, it is estimated that the amount of penetration of the workpiece W will be greatest at the third penetration portion 59, so the distance from the laser head 40 to the first surface 51 at the third penetration portion 59 can be more inexpensively determined as the focal length of the laser light LB.

[0072] Furthermore, by capturing images of a plurality of penetration parts 56, even if the actual focal length of the laser light LB is unknown, the focal length can be found because the laser light LB is divided into a penetration zone and a non-penetration zone at some point.

[0073] In addition, by periodically checking the calculated focal length, the irradiation conditions (focal length) of the laser light LB on the workpiece W can be managed, and if the focus shifts, the irradiation position of the laser light LB can be corrected or maintenance of the optical equipment can be performed, contributing to stable operation of the laser processing machine.

[0074] Other Embodiments The above embodiment may be configured as follows.

[0075] In this embodiment, the distance H from the laser head 40 to the first surface 51 is smallest at the emission start point of the laser beam LB, and the distance H increases each time the laser head 40 is moved in the Y direction, but this is not limiting. For example, the distance H from the laser head 40 to the first surface 51 may be largeest at the emission start point of the laser beam LB, and the distance H may decrease each time the laser head 40 is moved in the Y direction. [Industrial Applicability]

[0076] As described above, the present invention provides the highly practical effect of being able to specify the focal length of laser light relatively easily, and is therefore extremely useful and has high industrial applicability. [Explanation of symbols]

[0077] 1 Focal length identification device 20 Imaging unit 32 Storage section 33 Calculation section 35 tables 40 Laser Head 51 Page 1 52 Side 2 55 Laser processing section 56 Penetration 57 First penetration 58 Second penetration 59 Third penetration 60 Reference position 65 intermediate position LB laser light double work

Claims

1. A focal length specifying device that specifies a focal length of laser light emitted from a laser head to a workpiece, The workpiece has a first surface from which the laser light is emitted and a second surface opposite to the first surface, a plurality of laser-processed portions are formed on the first surface by emitting the laser light at intervals in a predetermined first direction; a plurality of through-holes having different outer diameters are formed in the second surface by the laser-processed portion melted so as to penetrate to the second surface; an imaging unit that moves relatively in the first direction from a predetermined reference position on the second surface and images each of the plurality of penetration portions; a calculation unit that calculates the focal length of the laser light, The calculation unit Identifying a plurality of the penetration parts whose outer diameters are equal to or greater than a predetermined threshold value from among the plurality of penetration parts imaged by the imaging unit; Among the plurality of penetration parts identified as having a density equal to or greater than the threshold value, a first penetration part located at one end side in the first direction and a second penetration part located at the other end side in the first direction are identified; Identifying a third penetration portion located at an intermediate position between the first penetration portion and the second penetration portion Focal length identification device.

2. 2. The focal length specifying device of claim 1, a storage unit that stores a table indicating a relationship between a distance from the reference position to the penetration portion and a distance from the laser head to the first surface at the penetration portion; The calculation unit calculates the distance from the laser head to the first surface at the third penetration portion based on the table stored in the storage unit and the distance from the reference position to the third penetration portion. Focal length identification device.

3. 3. The focal length specifying device according to claim 1, a display unit that displays an image of the third penetration portion; Focal length identification device.

4. 3. The focal length specifying device of claim 2, a display unit that displays the distance from the laser head to the first surface at the third penetration portion calculated by the calculation unit; Focal length identification device.

5. 3. The focal length specifying device according to claim 1, The threshold value is smaller than the outer diameter of the through-holes located on both end sides in the first direction. Focal length identification device.

6. A focal length specifying method for calculating a focal length of laser light emitted from a laser head to a workpiece, The workpiece has a first surface from which the laser light is emitted and a second surface opposite to the first surface, a plurality of laser-processed portions are formed on the first surface by emitting the laser light at intervals in a predetermined first direction; a plurality of through-holes having different outer diameters are formed in the second surface by the laser-processed portion melted so as to penetrate to the second surface; an imaging step of relatively moving from a predetermined reference position on the second surface along the first direction to image each of the plurality of penetration portions; A step of identifying a plurality of the penetration parts whose outer diameters are equal to or greater than a predetermined threshold value from among the plurality of penetration parts imaged in the imaging step; Identifying a first penetration portion located at one end side in the first direction and a second penetration portion located at the other end side in the first direction from among the plurality of penetration portions identified as being equal to or greater than the threshold value; and identifying a third penetration portion located at an intermediate position between the first penetration portion and the second penetration portion. How to determine focal length.

7. 7. The method for specifying a focal length according to claim 6, a laser processing step of forming a plurality of the laser-processed portions on the first surface of the workpiece before the imaging step; The laser processing step includes: a first step of emitting the laser light from the laser head to the first surface to form the laser processed portion; a second step of moving the laser head relatively to the workpiece after the first step to a position spaced a first distance in the first direction and a second distance in a second direction along the emission direction of the laser light; and a third step of alternately repeating the first step and the second step to form a plurality of the laser-processed portions on the first surface at intervals in the first direction. How to determine focal length.

Images