JP2010227962A - Laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve laser beam machining with high accuracy by obtaining the deviation including all possible factors for generating the deviation at the laser beam application position. <P>SOLUTION: Laser beam is applied from a laser beam machine 16 to a non-machining area 20b of a workpiece 20 to form a laser beam machining trace. The difference between the coordinate position of a positioning mark provided in the non-machining area 20b and the coordinate position of the laser beam machining trace is obtained. Based on the obtained difference, the laser beam application position on the workpiece 20 is corrected, and the workpiece 20 is subjected to the laser beam machining by the laser beam machine 16. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser processing method for processing by irradiating a workpiece with laser light.

  In the laser processing apparatus, for example, when cutting a workpiece, cutting is performed while moving the irradiation position of the laser beam along the cutting line. To move the irradiation position of the laser beam on the workpiece, a method of moving the workpiece with respect to the laser beam whose irradiation position is fixed and a method of moving the laser beam with respect to the workpiece whose position is fixed There is.

  In the method of moving the workpiece relative to the laser beam, the laser irradiation position is moved on the workpiece by placing the workpiece on a movable stage and moving the stage in the XY direction. In this method, since a stage with a large mass must be moved, in order to move the stage with high accuracy, the moving speed must be slowed down, and the laser processing time becomes long.

  On the other hand, in the method of moving the laser beam with respect to the workpiece whose position is fixed, the irradiation position of the laser beam can be easily moved at high speed by deflecting the laser beam using a galvanometer mirror. Therefore, laser processing can be performed in a short time by using a laser processing apparatus using a galvanometer mirror. However, in this method, the temperature of a laser processing apparatus including a galvanometer mirror and an optical system rises during laser processing, and each part is thermally deformed, and the laser irradiation position accuracy may deteriorate due to the influence.

  Specifically, for example, when the irradiation position of the laser beam is controlled using a galvanometer mirror, the position of the galvanometer mirror changes due to thermal expansion / contraction due to temperature change of the galvanometer mirror body or the fixing jig, etc. The irradiation position accuracy may be affected. In order to prevent this, a temperature sensor is provided around the galvano mirror to detect the temperature of the galvano mirror, and the laser irradiation position accuracy is maintained by correcting the change in the laser irradiation position due to the temperature change. Yes. Further, the heat source is moved away from the galvanometer mirror to suppress the temperature increase of the galvanometer mirror so that the laser irradiation position is not changed as much as possible.

  Therefore, it has been proposed to correct the laser irradiation position in the laser irradiation apparatus by detecting the deviation of the laser irradiation position using the guide laser beam, obtaining the correction amount of the deviation and feeding it to the drive unit of the galvano mirror. (For example, refer to Patent Document 1).

JP 58-2224088

  The correction mechanism disclosed in Patent Document 1 performs correction inside the housing of the laser irradiation apparatus, and includes a stage on which a workpiece is placed, a frame that supports the laser irradiation apparatus with respect to the stage, and the like. The overall thermal deformation is not considered. However, if an attempt is made to design / manufacture a laser irradiation position correction mechanism considering the entire laser processing apparatus, it is necessary to provide a plurality of expensive photoelectric conversion devices and temperature sensors, which is not practical from the viewpoint of manufacturing cost. In addition, a correction mechanism for correcting distortion of the mirror and lens that controls the laser light is necessary, and the provision of this correction mechanism is a factor in increasing the cost of the laser processing apparatus. Therefore, development of an inexpensive laser irradiation position correction mechanism with a simple configuration is desired.

  According to one embodiment, a laser processing mark is formed by irradiating a laser beam from a laser processing machine to a non-working area of a workpiece, and the coordinate position of the positioning mark provided in the non-working area and the laser processing mark A laser processing method is provided in which a difference from the coordinate position is obtained, a laser irradiation position on the workpiece is corrected based on the obtained difference, and the workpiece is laser processed by the laser processing machine.

  According to the above-described laser processing method, the laser processing position is actually obtained by performing laser processing on the non-processed region, and the deviation amount of the laser irradiation position is obtained from the laser processing trace. For this reason, it is possible to obtain the amount of deviation including all factors that may cause deviation in the laser irradiation position, and it is possible to realize highly accurate laser processing.

1 is a simplified diagram illustrating an overall configuration of a laser processing apparatus according to an embodiment. It is a flowchart of the laser processing process performed with the laser processing apparatus shown in FIG. It is a top view of a plastic sheet. It is a figure which shows the image of the alignment mark and laser processing trace which image-detected one of the two cameras. It is a figure which shows the image of the alignment mark and laser processing trace which image-detected on the other side of two cameras.

  FIG. 1 is a simplified diagram showing the overall configuration of a laser processing apparatus according to an embodiment. As an example, the laser processing apparatus 10 shown in FIG. 1 is a processing apparatus that performs a process of half-cutting a transparent plastic sheet using a laser beam.

  The laser processing apparatus 10 includes a base portion 12, a laser housing fixing portion 14 fixed to the base portion 12, and a laser processing machine 16 supported by the laser housing fixing portion 14. The laser beam machine 16 is a galvano built-in laser beam machine that irradiates the laser beam while deflecting it with a galvanometer mirror.

  The base portion 12 is a portion that becomes a main body of the laser processing apparatus 10. On the base portion 12, a suction stage 18 for placing a plastic sheet 20 as a workpiece is disposed. The suction stage 18 is connected to a suction mechanism (not shown) provided in the base portion 12. By sucking the plastic sheet on the suction stage 18 with a suction mechanism, the plastic sheet can be fixed on the suction stage 18.

  The suction stage 18 is moved by a stage moving mechanism (not shown) to a work set position (a position indicated by a solid line in FIG. 1) and a processing position to which the laser beam from the laser processing machine 16 is irradiated (shown by a dotted line in FIG. 1). Position). The movement of the suction stage 18 is controlled by a stage control device 22 provided in the base portion 12.

  Two cameras 24 are arranged below the suction stage 18. The two cameras 24 are, for example, CCD cameras, and an alignment mark which is a positioning mark provided on the transparent plastic sheet 20 placed on the suction stage 18 formed of transparent glass or the like is used as a transparent plastic sheet. Images can be taken from the back side of 20. In the present embodiment, it is assumed that the alignment marks are provided at two locations in the non-processed region on the diagonal line of the plastic sheet 20, and two cameras 24 are arranged in accordance with the positions of the alignment marks. In this embodiment, since the plastic sheet 20 is transparent, the alignment mark provided on the front side of the plastic sheet 20 can be imaged from the back side. When the workpiece is not transparent and the alignment mark is provided on the front side of the workpiece, the camera may be disposed on the front side of the workpiece.

  The image data of the alignment mark imaged by the camera 24 is sent to the image processing device 26 provided in the base unit 12. The image processing device 26 performs coordinate analysis on the image data of the alignment mark and specifies the positional deviation of the plastic sheet 20 on the suction stage 18. Information relating to the positional deviation amount of the plastic sheet 20 specified by the image processing device 26 is supplied to the laser processing machine 16. The laser beam machine 16 laser-processes the plastic sheet 20 while adjusting the irradiation position of the laser beam according to the positional deviation amount of the plastic sheet 20.

  The overall operation control of the laser processing apparatus 10 is performed by a control unit 28 provided in the base unit 12. The control unit 28 is a computer such as a personal computer, for example, and the stage control device 22 and the image processing device 26 described above may be included in the control unit 28.

  In the present embodiment, a duct 30 that extends from the laser irradiation portion of the laser processing machine 16 toward the processing position is provided. The duct 30 is provided in order to collect smoke generated during processing of the plastic sheet 20 so as not to fill the surroundings. The smoke collected in the duct 30 is discharged to a place away from the plastic sheet 20. Further, by providing the duct 30, it is possible to prevent the camera 24 from being damaged by scattered light generated during laser processing.

  Further, a display device 32 is attached to the base unit 12, and the state of the laser processing apparatus 10 can be displayed on the display device 32, and an operation command can be input via the display device 32.

  Next, a laser processing method when processing the plastic sheet 20 with the laser processing apparatus 10 shown in FIG. 1 will be described. FIG. 2 is a flowchart of a laser processing step performed by the laser processing apparatus 10.

  In order to perform laser processing of the plastic sheet 20, first, in step S <b> 1, an operator places the plastic sheet 20 as a workpiece on the suction stage 18 of the laser processing apparatus 10. At this time, the suction stage 18 has moved to the work set position. When the plastic sheet 20 is placed on the suction stage 18, the suction mechanism is activated and the plastic sheet 20 is fixed to the suction stage 18.

  Next, in step S2, the camera 24 images the alignment mark of the plastic sheet 20 and detects the alignment mark image. Then, the image processing device 26 obtains the coordinate position A of the alignment mark from the image data including the alignment mark.

  Subsequently, in step S3, the control unit 28 performs an alignment process. In the alignment process, the position where the laser beam is irradiated from the laser processing machine 16 is obtained based on the coordinate position A of the alignment mark. In step S4, the control unit 28 stores and registers the image when the alignment mark is detected in the memory.

  Next, in step S5, the control unit 28 drives the moving mechanism to move the suction stage 18 to the processing position. Therefore, the plastic sheet 20 fixed to the suction stage 18 also moves to the processing position. Then, the laser processing machine 16 irradiates the laser beam with the center of the alignment mark of the plastic sheet 20 as a target, and forms a laser processing mark on the alignment mark.

  Thereafter, in step S6, the control unit 28 drives the moving mechanism to return the suction stage 18 to the work set position, and again detects the alignment mark image. A laser processing trace is formed on or near the alignment mark at this time as described later.

  Here, the alignment mark and the laser processing trace will be described with reference to FIGS.

  FIG. 3 is a plan view of the plastic sheet 20. The plastic sheet 20 has a processing region 20a that is laser processed and a non-processing region 20b that is not processed outside the processing region 20a. The non-processed area 20b is an outer peripheral part of the plastic sheet 20, and is a part that is removed after laser processing.

  In the non-processed region 20b, a laser processing trace forming region 20c is provided in the upper right corner, and an alignment mark 40-1 is provided in the laser laser processing trace forming region 20c. Similarly, in the non-processed area 20b, a laser processing trace forming area 20c is provided also in the lower left corner, and an alignment mark 40-2 is provided in the laser processing trace forming area 20c.

  The laser processing trace forming area 20c is an area provided for forming a laser processing trace as will be described later. The laser processing region 20c is preferably coated with a marking material that easily changes to black by laser processing so that the outline of the laser processing trace becomes clear when an image of the laser processing trace is detected. . As such a marking material, it is known that, for example, a molybdenum-containing composite oxide is suitable. Alternatively, a paint containing a phosphoric acid-containing inorganic substance, a boric acid-containing inorganic substance, bismuth oxide, or the like can also be used as a material that easily reacts to a laser.

  FIG. 4 shows images of the alignment mark 40-1 and the laser processing trace 42-1 detected by one of the two cameras 24. FIG. 5 shows images of the alignment mark 40-2 and the laser processing trace 42-2 that have been detected on the other side of the two cameras 24. FIG. The alignment marks 40-1 and 40-2 are cross-shaped marks, but other shapes such as rectangles and squares or combinations thereof may be used as long as the positioning reference can be obtained from the image. Good.

  In the present embodiment, the alignment mark 40-1 provided on the plastic sheet 20 is a cross-shaped mark as shown in FIG. The image shown in FIG. 4A is an image of the alignment mark 40-1 taken in step S2. The image shown in FIG. 4B is an image of the alignment mark 40-1 taken in step S6. On the alignment mark 40-1 or in the vicinity of the alignment mark 40-1 in the image shown in FIG. 4B, a laser processing mark 42-1 formed by irradiating laser light in step S5 is formed.

  Here, the target position for laser processing in step S5 is the alignment registered in step S3 so that the laser processing trace 42-1 passes through the center of the alignment mark 40-1 as shown by the dotted line in FIG. It is set based on the image of the mark 40-1. That is, if there is no error (shift) in the laser irradiation position, a laser processing trace should be formed at the position indicated by the dotted line in FIG.

  However, if the optical components in the laser processing machine 16 are distorted, or if the laser processing machine 16 or the laser housing fixing part 14 that supports the laser processing machine 16 is thermally deformed, the laser beam will be lost. It becomes impossible to irradiate the target position with light. That is, even if it is set to irradiate the laser beam to the target position, the laser beam is irradiated to the position deviated from the center of the cross-shaped alignment mark 40-1 as shown in FIG. 42-1 is formed. At this time, the distance D1 between the center of the alignment mark 40-1 and the center of the laser processing mark 42-1 shown in FIG. 4B corresponds to the deviation amount of the laser irradiation position. In FIG. 4, the vertical direction corresponds to the vertical direction of the plastic sheet 20. Therefore, the shift amount (distance D1) shown in FIG. 4B corresponds to the vertical shift amount of the plastic sheet 20.

  The image shown in FIG. 5A is an image of the alignment mark 40-2 captured in step S2. The image shown in FIG. 5B is an image of the alignment mark 40-2 captured in step S6. On the alignment mark 40-2 or in the vicinity of the alignment mark 40-2 in the image shown in FIG. 5B, a laser processing trace 42-2 formed by irradiating laser light in step S5 is formed.

  Here, the target position for laser processing in step S5 is the alignment registered in step S3 so that the laser processing trace 42-2 passes through the center of the alignment mark 40-2 as shown by the dotted line in FIG. It is set based on the image of the mark 40-2. That is, if there is no error (shift) in the laser irradiation position, a laser processing trace should be formed at the position indicated by the dotted line in FIG.

  However, if the optical components in the laser processing machine 16 are distorted or if the laser housing fixing part 14 or the base part 12 that supports the laser processing machine 16 is thermally deformed, the laser beam is brought to the target position. Irradiation is impossible. That is, even if the laser beam is set to irradiate the target position, as shown in FIG. 5B, the laser beam is radiated to the position deviated from the center of the cross-shaped alignment mark 40-1, and the laser processing trace is obtained. 42-2 is formed. At this time, the distance D2 between the center of the alignment mark 40-2 and the center of the laser processing mark 42-2 shown in FIG. 5B corresponds to the amount of deviation of the laser irradiation position. In FIG. 5, the left-right direction corresponds to the horizontal direction of the plastic sheet 20. Therefore, the deviation amount (distance D2) shown in FIG. 5B corresponds to the lateral deviation amount of the plastic sheet 20.

  Returning to FIG. 2, the description of the laser processing step will be continued. If the alignment mark and the laser processing trace are detected in step S6, the process proceeds to step S7. In step S7, the image processing device 26 obtains the center of the laser processing trace from the image, and obtains the coordinate position B with the center position as the laser scanning position. In step S7, the control unit 28 obtains the difference between the coordinate position A and the coordinate position B for each of the alignment marks 40-1 and 40-2. This difference corresponds to the distances D1 and D2 representing the deviation amount of the laser irradiation position.

  In step S <b> 8, the control unit 28 transmits information on the distances D <b> 1 and D <b> 2 representing the deviation amount of the laser irradiation position to the laser processing machine 16. Thereafter, in step S10, the suction stage 18 is moved to the processing position, the plastic sheet 20 is disposed at the laser processing position, and the plastic processing of the plastic sheet 20 is performed. The laser processing at this time is performed after correcting the laser irradiation position based on the information of the distances D1 and D2 representing the deviation amount of the laser irradiation position. Therefore, the laser irradiation position can be accurately performed without any positional deviation.

  The correction of the laser irradiation position can be performed in both the vertical direction (Y direction) based on the distance D1 and the horizontal direction (X direction) based on the distance D2. Further, by detecting the angle between the center line of the alignment mark and the center line of the laser processing trace, the amount of deviation in the rotation direction (θ direction) of the plastic sheet 20 can be obtained and corrected.

  When the laser processing in step S10 continues for a long time, the above-described processing from step S5 to step S9 may be performed again during the laser processing. That is, if the laser processing is continued, the temperature of each part of the laser processing apparatus 10 becomes higher than the time when the laser processing is started. Therefore, in order to correct the deviation of the lower laser irradiation position due to this, the laser processing is performed. In the middle of the process, the amount of deviation is obtained again and corrected.

  In the above-described embodiment, the alignment marks are provided in two places, one is used for obtaining the vertical deviation amount, and the other is used for obtaining the horizontal deviation quantity. However, the alignment marks are not necessarily provided in two places. There is no need to provide it. For example, two laser processing traces are formed in the vertical direction and the horizontal direction for one alignment mark, and the vertical shift amount and the horizontal shift amount can be obtained from an image captured by one camera. it can. In this case, it is not necessary to provide two cameras, and only one camera is required.

  As described above, according to the present embodiment, laser processing is actually performed on the non-processed region 20b, and the deviation amount of the laser irradiation position is obtained from the laser processing trace. For this reason, it is possible to obtain the amount of deviation including all factors that may cause deviation in the laser irradiation position, and it is possible to realize highly accurate laser processing.

  The alignment mark is originally provided for positioning the plastic sheet 20 and is not specially provided for correcting the laser irradiation position. The camera 24 is also a component originally provided in the laser processing apparatus 10 for positioning the plastic sheet 20, and is not specially provided for correcting the laser irradiation position. Therefore, the laser processing method according to the present embodiment can be easily carried out without changing the structure of the conventional laser processing apparatus only by changing the control in the control unit 28 and the image processing apparatus 26.

As described above, the present specification discloses the following matters.
(Appendix 1)
Laser processing marks are formed by irradiating laser light from the laser processing machine to the non-processed area of the workpiece,
Find the difference between the coordinate position of the positioning mark provided in the non-processing area and the coordinate position of the laser processing trace,
A laser processing method in which a laser irradiation position on a workpiece is corrected based on the obtained difference, and the workpiece is laser processed by the laser processing machine.
(Appendix 2)
A laser processing method according to attachment 1, wherein
A laser processing method for recognizing a difference between a coordinate position of the positioning mark and a coordinate position of the laser processing mark from an image obtained by imaging the non-processing area.
(Appendix 3)
The laser processing method according to attachment 2, wherein
A laser processing method in which a material that changes color in response to a processing laser beam is applied to an area where the positioning mark is provided on the workpiece.
(Appendix 4)
A laser processing method according to attachment 1, wherein
Two positioning marks are provided on the workpiece, the vertical displacement of the laser irradiation position is obtained using one positioning mark, and the lateral position of the laser irradiation position is obtained using the other positioning mark. A laser processing method for obtaining a deviation amount.
(Appendix 5)
A laser processing method according to attachment 1, wherein
A laser processing method in which the positioning mark is provided near the outer periphery of the workpiece.
(Appendix 6)
A laser processing method according to attachment 1, wherein
While laser processing the workpiece,
A laser beam is formed by irradiating the non-processed area of the workpiece with a laser beam,
Find the difference between the coordinate position of the positioning mark provided in the non-processed area and the coordinate position of the laser processing mark that has been formed again,
A laser processing method in which the laser processing is continued by correcting the laser irradiation position on the workpiece based on the obtained difference.
(Appendix 7)
A laser beam machine fixed to the base portion via a fixed portion;
A stage provided on the base and on which the workpiece is placed and fixed;
A camera for imaging a positioning mark provided on a workpiece on the stage;
A control unit for controlling the operation of the laser processing machine, the stage, and the camera,
The control unit forms a laser processing mark by irradiating a laser beam from a laser processing machine to a non-processed area of the workpiece, and the coordinate position of a positioning mark provided in the non-processed area and the laser processing mark The laser beam machine, the stage, and the laser beam are machined so as to correct the laser irradiation position on the workpiece based on the obtained difference and laser process the workpiece with the laser beam machine. A laser processing device that controls the operation of the camera.

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 12 Base part 14 Laser housing fixing | fixed part 16 Laser processing machine 18 Adsorption stage 20 Plastic sheet 20a Processing area 20b Non-processing area 20c Laser processing trace formation area 22 Stage control apparatus 24 Camera 26 Image processing apparatus 28 Control part 30 Duct 32 Display device 40-1, 40-2 Alignment mark 42-1, 42-2 Laser processing trace

Claims (5)

Laser processing marks are formed by irradiating laser light from the laser processing machine to the non-processed area of the workpiece,
Find the difference between the coordinate position of the positioning mark provided in the non-processing area and the coordinate position of the laser processing trace,
A laser processing method in which a laser irradiation position on a workpiece is corrected based on the obtained difference, and the workpiece is laser processed by the laser processing machine. The laser processing method according to claim 1,
A laser processing method for recognizing a difference between a coordinate position of the positioning mark and a coordinate position of the laser processing mark from an image obtained by imaging the non-processing area. The laser processing method according to claim 2,
A laser processing method in which a material that changes color in response to a processing laser beam is applied to an area where the positioning mark is provided on the workpiece. The laser processing method according to claim 1,
Two positioning marks are provided on the workpiece, the vertical displacement of the laser irradiation position is obtained using one positioning mark, and the lateral position of the laser irradiation position is obtained using the other positioning mark. A laser processing method for obtaining a deviation amount. A laser processing machine fixed to the base part via a fixing part;
A stage provided on the base and on which the workpiece is placed and fixed;
A camera for imaging a positioning mark provided on a workpiece on the stage;
A control unit for controlling the operation of the laser processing machine, the stage, and the camera,
The control unit forms a laser processing trace by irradiating a laser beam from a laser processing machine to a non-processing area of the workpiece, and a coordinate axis of a positioning mark provided in the non-processing area and a coordinate of the laser processing trace The laser processing machine, the stage, and the camera so as to obtain a difference from a position, correct a laser irradiation position on the work based on the obtained difference, and laser process the work with the laser processing machine. Laser processing device that controls the operation of the machine.

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