KR100696395B1 - Method for controlling the LASER beam in a LASER processing apparatus - Google Patents

Abstract

A laser beam control method of a laser processing apparatus is disclosed. The laser beam control method of the present invention includes the steps of: (a) setting a reference coordinate value range of a start area / end area / irradiation area; (b) detecting a position coordinate where the optical axis of the laser head is located; (c) determining which area among the start area, the irradiation area, and the end area belongs to the position coordinates; And the control unit turns on the laser beam only when the position coordinate is present in the irradiation area after the position coordinate enters the start area, so that the processing defect is caused by the laser beam being irradiated to a point far beyond the scheduled line. This is prevented, a quick control response and an accurate control operation are ensured, and over machining due to the laser beam overlapping irradiation is suppressed when a plurality of scheduled lines are adjacent to each other.

Laser beam control method, start area, end area, irradiation area, processing line

Description

Method for controlling the LASER beam in a LASER processing apparatus}

1 is an explanatory view showing a processing line in the conventional laser beam control method.

FIG. 2 is an explanatory view showing a state in which machining is poor due to deviation of a processing line of a laser beam in a conventional laser beam control method; FIG.

3 is an explanatory view showing a state in which a plurality of processing lines are adjacent in the conventional laser beam control method.

4 is an explanatory diagram showing a machining failure state by overlapping irradiation of a laser beam in a conventional laser beam control method.

5 is a perspective view schematically showing a laser processing apparatus of the present invention.

6 is a perspective view schematically showing a processing state of a workpiece by the laser processing apparatus of the present invention.

FIG. 7 is an explanatory view showing an on / off state of a laser beam when the irradiation area does not overlap the start area and the end area in the laser beam control method of the present invention; FIG.

FIG. 8 is an explanatory view showing an on / off state of a laser beam when the irradiation area overlaps the start area and the end area in the laser beam control method of the present invention; FIG.

9 is a flow chart according to the laser beam control method of the present invention.

<Description of Symbols for Main Parts of Drawings>

100 Workpiece 103 ... Electrode

110.Table 121.Support

122 ... laser head arm 123 ... connection member

130 ... laser oscillator 140 ... laser head

150 ... optical fiber 170 ... control unit

171 Detecting unit 180 Vision head

200 ... laser beam 300 ... starting area

400 ... irradiation area 500 ... end area

600 Expected line A1, A3 ... Starting point

A2, A4 ... end point

P1 to P6 ... Optical axis travel path of laser head

The present invention relates to a laser beam control method of a laser processing apparatus, and more particularly, a laser beam control method of a laser processing apparatus for processing a workpiece while a laser head for irradiating a workpiece with a laser head and a table for supporting the workpiece are moved relative to each other. It is about.

The laser processing apparatus is capable of high precision machining in a non-contact manner, regardless of the material of the workpiece. Processing with a laser beam focused at a narrow spot point of a predetermined diameter ensures thermal stability of the workpiece, and can perform ultra-precision processing without being limited by the size of the processing area.

In order to process workpieces of various types and sizes, it is necessary to control the width of the laser beam, the distance to be focused, the diameter of the spot, the light intensity of the laser beam, the transfer of the workpiece, and the like in real time at high speed and precision.

The table for supporting the workpiece and the laser head for irradiating the laser beam are provided to be movable along at least one of the X, Y, and Z axes. The laser beam is irradiated to the workpiece, and the workpiece is processed while the table and the laser head are moved relative to the machining line.

1 is an explanatory view showing a processing line 60 in the conventional laser beam control method. The starting point A1 is the reference coordinate at the point where the start of laser processing is prepared, and the ending point A2 is the reference coordinate at the point where the laser processing is finished. The scheduled line 60 is a straight line connecting the starting point A1 and the ending point A2, and the optical axis of the laser head in which the focus of the laser beam exists must follow the expected line 60 to reduce the processing error. FIG. 1 shows electrodes 10 formed on a flat panel display panel such as an LCD and a PDP, and electrodes 10 having a line width d1 corresponding to the width of an irradiated laser beam are cut.

2 shows a state in which a laser beam deviates from the processing line 60 in the conventional laser beam control method, whereby a processing defect occurs. The trajectory 61 of the laser head optical axis is caused by unpredictable disturbances such as the inertia of the table on which the workpiece is supported, the laser head irradiating the laser beam, the backlash of the drive gear, and the foreign matter in the transport path. It is out of the machining line 60 connecting the start point A1 and the end point A2. When the optical axis of the laser head is moved along the reference numeral 61, the laser beam is in an on state at a position far beyond the expected line 60, so that processing defects in which unwanted portions of the workpiece are cut are concerned. .

In the machining operation, it is quite difficult to accurately follow the optical axis of the laser head without error in the reference coordinates of the start point A1, the end point A2, and the processing schedule line 60 set in advance before the machining operation. If a complicated control operation is performed to follow the optical axis of the laser head to the reference coordinates, the response time of the controller may be slow, and the response value may be unstable, resulting in an uncontrollable state. In addition, the slower the response time of the controller, the faster the relative movement speed of the laser head and the table, the faster the control operation due to the physical characteristics of the laser processing apparatus. Due to such poor control, unwanted electrodes may be cut and processing defects may occur.

3 is an explanatory view showing a state in which a plurality of processing lines 60 are adjacent in the conventional laser beam control method. FIG. 4 illustrates a state in which excessive machining occurs as the mechanical beam trajectory 61 of the laser head does not follow the processing line 60 and the laser beam is superimposed. Due to unforeseen disturbances such as the inertia of the table and the laser head, gear backlash, and the like, there is a possibility that over machining may occur if the laser head is out of the processing line 60 and the laser beam is superimposed along the reference numeral 61. .

The present invention is to improve the above-mentioned problems, the laser beam control method that can reduce the processing defects by turning off the laser beam when the laser head is moved from a position outside the processing line due to unpredictable disturbance The purpose is to provide.

Laser beam control method of the present invention for achieving the above object,

(a) a start area including a start point at which laser processing starts and a predetermined area around it, an end area including an end point at which laser processing ends and a predetermined area around it, and between the start area and the end area Setting a reference coordinate range of the irradiation area;

(b) detecting a position coordinate where the optical axis of the laser head is located with respect to the workpiece;

(c) determining which of the starting area, the irradiation area and the ending area belongs to the position coordinates; And the laser beam is turned on only when the position coordinate is present in the irradiation area after entering the start area.

together,

(d) When the position coordinate enters the start area, the start area pass index is set to 1, and when the start area pass index is set to 1, the position coordinate is out of the irradiation area and exists in the end area. Setting the start area pass index to 0 in a second step; Further, it is preferable that the control unit turns on the laser beam only when the position coordinate is present in the irradiation area in the state where the start area passage index is set to 1.

The start area, the irradiation area, and the end area are set to the limits of the coordinate range where no machining defects occur in the workpiece.

The irradiation area includes at least a portion of the processing line connecting the start point and the end point in a straight line or a curve.

The irradiation area may partially overlap at least one of the start area and the end area. Of course, an embodiment in which the irradiation area does not overlap any one of the start area and the end area is possible.

The start area, irradiation area, and end area are preferably set by a vision head provided to capture a vision image of the workpiece.

On the other hand, in the step (b), it is preferable to convert the relative movement of the laser head and the table into an electrical signal and count the amount of change.

Hereinafter, with reference to the accompanying drawings an embodiment of a laser beam control method of a laser processing apparatus according to the present invention will be described in detail.

First, a laser processing apparatus to which the laser beam control method of the present invention is applied will be described. 5 is a perspective view schematically showing the laser processing apparatus of the present invention, Figure 6 is a perspective view schematically showing a state in which the workpiece is processed by the laser processing apparatus of the present invention.

As a work piece 100, a flat panel display panel such as an LCD or a PDP is taken as an example, and a laser processing apparatus for cutting the electrodes 103 formed at intervals of several tens of micrometers on the flat panel display panel with a laser beam 200 is illustrated in FIGS. 5 and FIG. 6 is shown.

For laser processing, a laser oscillator 130 for emitting a laser, a laser head 140 for focusing the laser on a spot and irradiating the workpiece 100, a laser oscillator 130, and a laser head 140 A connecting optical system is needed. Laser head 140 must be precisely positioned within several micrometers for ultra-precision machining. The laser head 140 needs to be installed so that the weight and volume are small and the mass (rotation) moment of inertia is minimized. The optical fiber 150 is used as a connection optical system, and the laser oscillator 130 and the laser head 140 are separately installed to reduce the weight of the laser head 140.

In order to set the reference coordinate value at which the workpiece 100 is processed, the vision head 180 is provided. Although not shown in FIG. 5, it is preferable that the optical axes of the laser head 140 and the vision head 180 coincide with each other. To this end, a mirror member (not shown) coated with a visible light reflection film or a laser reflection film is provided inside the laser head 140. The vision head 180 may also be used for the purpose of monitoring the processing state of the workpiece 100.

The laser head 140 and the vision head 180 are coupled to the connecting member 123 so that the Z-axis can be moved, and the connecting member 123 is coupled to the laser head arm 122 so as to be movable in the X-axis. The table 110 supporting the 100 is coupled to the support 121 to be movable in the Y axis. Therefore, the workpiece 100 is transferred to a predetermined machining position by the relative movement of the laser head 140 and the table 110. Various embodiments are possible for the transfer of the workpiece 100 without being limited to the illustrated.

The laser head 140 and the table 110 are relatively moved by a driving source such as a motor not shown. For example, when an encoder (not shown) is coupled to the motor, the rotation angle of the motor is output as a pulse signal of a constant voltage from the encoder. The rotation angle of the motor is calculated by counting the number of pulses, and the relative position coordinates of the laser head 140 and the table 110 are calculated by converting the rotation angle. Example. The motor is driven by a motor driver (not shown) including a driving chip and a power supply unit. The motor driver is connected to a motion controller (not shown) that controls relative movement of the laser head 140 and the table 110. It is preferably connected to the control unit 170.

A1 and A3 are starting points for preparing for the start of laser processing, and A2 and A4 are end points for finishing laser processing. The start point and the end point may be inputted manually, or the vision head 180 may capture a vision image of the workpiece 100 and set the start point and the end point by processing the vision image on a computer or the controller 170. have.

The starting point and the end point, and the straight line or the curved line to be connected to the processing line 600 becomes a trajectory vector to pass through the workpiece 100 while the optical axis of the laser head 140 irradiates the laser beam 200. The optical axis of the laser head 140 is the optical central axis of the laser beam 200 to be irradiated. The laser beam has a width of about 50 μm at a focal point, and a cutting line width d1 of the electrode 103 of the flat panel display panel, which is the workpiece 100, is a corresponding value.

7 and 8 illustrate a start area 300 and an end area 500 and an irradiation area 400 set in a predetermined area around a processing line 600 of a straight line or a curve connecting the start point and the end point, and the straight line or the curve. Illustrated. It is almost impossible for the optical axis of the laser head 140 to accurately follow the reference coordinate values of the starting point A1, the end point A2, and the processing schedule line 600 during the machining operation without errors. In the present invention, in consideration of a predetermined error, the start area 300, the irradiation area 400, and the end area 500 are set in advance, and when the optical axis of the laser head 140 enters the area, the starting point / scheduled line (600) / endpoints logically reached, ensuring fast response time and accurate control. This in turn reduces machining errors resulting from poor control behavior.

P1 to P6 represent a trajectory through which the optical axis of the laser head 140 passes. The solid line means that the laser beam 200 is on and the dotted line is off. The control unit 170 cuts off the power of the laser oscillator 130 or includes a laser beam blocking means (not shown) in the laser head 140, and the control unit 170 operates this to turn off the laser beam 200 ( off).

The start area 300 and the end area 500 are squares having a width of about 20 to 50 μm in which a predetermined amount is extended in the front, rear, left, and right directions around the start and end points. The start area 300 and the end area 500 can also be set in the shape of a circle or a closed curve. The irradiation area 400 connecting the start area 300 and the end area 500 is an area where the laser beam 200 is irradiated onto the workpiece 100. The start area 300 and the end area 500 may be set to overlap the irradiation area 400 as shown in FIG. 8.

Referring to FIG. 7, the laser beam 200 is not turned on since the irradiation area 400 does not pass through the P1 path. In the P2 path, the start area 300 is first passed and the start area pass index is set to 1, and only when the optical axis of the laser head 140 exists in the irradiation area 400 with the start area pass index set to 1. The laser beam 200 is turned on. Therefore, the workpiece 100 outside the irradiation area 400 is not processed, thereby preventing processing defects. In the P3 and P4 paths, the laser beam 200 is turned on when the optical axis of the laser head 140 exists in the irradiation area 400 with the start area passing index set to 1, and the irradiation area 400 is turned on. If out of the laser beam 200 is off (off). In the P5 and P6 paths, since the laser head 140 does not pass through the start area 300 and the start area pass index is not set to 1, even if the optical axis of the laser head 140 exists in the irradiation area 400, the laser beam ( 200) does not turn on. When the optical axis of the laser head 140 completely exits the irradiation area 400 and enters the end area 500 while the start area pass index is set to 1, the laser beam 200 is turned off and the start area pass index is reset to 0. do.

In the embodiment of FIG. 8, the start area 300 and the irradiation area 400 overlap with reference numeral 340, and the irradiation area 400 and the end area 500 overlap with reference numeral 450. Also in this case, the control method of the laser beam 200 is the same as the embodiment of FIG. Since the P1 path does not pass through the irradiation area 400, the laser beam 200 is turned off. In the P2 path, the starting area passing indicator is set to 1 at the moment when the starting area 300 is entered, and the laser beam 200 is turned on when entering the irradiation area 400 in the state, and when it leaves the irradiation area 400. The laser beam 200 is turned off. In the P3 and P4 paths, the laser head 140 is positioned at the intersection area 340 of the start area and the irradiation area and the intersection area 450 of the irradiation area and the end area, as well as the irradiation area 400 with the start area passing index set to 1. The laser beam 200 is turned on even when there is an optical axis. In the P5 and P6 paths, since the start region pass indicator is not 1, the laser beam 200 is not turned on. When the optical axis of the laser head 140 completely exits the irradiation area 400 and enters the end area 500 while the start area pass index is set to 1, the laser beam 200 is turned off and the start area pass index is reset to 0. do.

9 is a flowchart illustrating a method for controlling the laser beam 200 of the present invention. First, in step 910, the reference coordinate range of the start area 300, the irradiation area 400, and the end area 500 is set by the vision head 180. In step 920, the controller 170 checks whether the laser beam 200 is turned off, and initializes the start region pass index to zero. In step 930, the control unit 170 receives the relative position coordinates between the current laser head 140 and the table 110 from the sensing unit 171. At predetermined time intervals interrupted until the machining operation is completed, the controller 170 receives the position information from the detector 171. That is, the combination of one start area 300 / irradiation area 400 / end area 500 is repeated at predetermined time intervals in which step 930 to step 980 are interrupted until the end of the work.

In operation 940, the controller 170 determines whether the received relative position coordinate value belongs to the start area 300, the irradiation area 400, and the end area 500. For the above determination, the relative position coordinate system where the relative position coordinate value between the laser head 140 and the table 110 is determined and the reference coordinate range of the start area 300 / irradiation area 400 / end area 500 are grasped. The reference coordinate system must be logically matched. Therefore, a conversion process for matching the origin of the relative position coordinate system and the reference coordinate system and the direction angle of the coordinate axis is necessary. The control unit 170 uses the position coordinate values of the optical axis of the laser head 140 identified in the relative position coordinate system through the above process as a reference of the start area 300 / irradiation area 400 / end area 500 identified in the reference coordinate system. Compare with the coordinate range.

According to the determination, if the position coordinate value of the optical axis of the laser head 140 exists in the start area 300, the start area pass index is set to 1 (950 and 951). Even if the current position coordinate does not exist in the start area 300, if the start area pass index is set to 1 through the start area 300 in the past, the optical axis of the laser head 140 may exist in the irradiation area 400. In this case, the laser beam 200 is turned on (960, 961, 962). If not present in the irradiation area 400, but exists in the end area 500, the start area pass index set to 1 is reset to 0 to prepare for the next machining operation (970, 971, 973). In this case, the laser beam 200 is also turned off since the irradiation area 400 is out (972). If the optical axis of the laser head 140 does not belong to any of the start area 300 / irradiation area 400 / end area 500, the laser beam 200 is turned off (974).

In the case where there are a plurality of machining trajectory vectors each consisting of one start point and end point and the machining schedule line 600, the start area 300 / irradiation area 400 / end area 500 shown in Figs. There are a plurality of them, and the control unit 170 repeatedly performs the above-described processing on them. On the other hand, the relative position coordinate values of the laser head 140 optical axis when the plurality of processing lines 600 illustrated in FIG. 3 are adjacent to each other, the abnormal trajectory illustrated in FIG. 4 due to unpredictable disturbance such as a mechanical error. Even if it moves, the irradiation of the laser beam 200 is not started immediately at the starting point A1, A3 in the laser beam control method of the present invention. That is, since the irradiation of the laser beam 200 is turned on only in the predetermined irradiation area 400 set in advance in consideration of the operating error and unpredictable disturbance of the laser processing apparatus, the overlapping irradiation of the laser beam 200 Over machining is prevented.

As described above, the laser beam control method of the laser processing apparatus according to the present invention has the following effects.

(1) Since the laser beam is turned on only when the optical axis of the laser head is present in the irradiation area, processing defects due to the laser beam being irradiated to a point far beyond the expected line of processing is prevented.

(2) When the optical axis of the laser head enters the preset start area / irradiation area / end area in consideration of a predetermined error, it is treated as logically reaching the start point / preparation line / end point. This is guaranteed.

(3) Since the laser beam is turned on only when the irradiation of the laser beam does not start immediately from the start point and the optical axis of the laser head is present in the irradiation area, the laser beam overlap irradiation when a plurality of processing lines are adjacent to each other. Due to excessive processing is suppressed.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art to which the art belongs can make various modifications and other equivalent embodiments therefrom. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the claims below.

Claims (8)

In the laser beam control method of a laser processing apparatus for processing a workpiece while the laser head for irradiating the workpiece to the laser beam and the table for supporting the workpiece relative movement, (a) a start area including a start point at which laser processing starts and a predetermined area around it, a end area including a finish point at which laser processing ends and a predetermined area around it, and between the start area and the end area, Setting a reference coordinate value range of the irradiation area including a processing line; (b) detecting a position coordinate where the optical axis of the laser head is located with respect to the workpiece; (c) determining which of the starting area, the irradiation area and the ending area belongs to the position coordinates; Including; The laser beam is turned on only when the position coordinate enters the start area and then exists in the irradiation area, and at least the area where the position coordinate leaves the irradiation area or an area where the processing line is overlapped. When present in the laser beam control method characterized in that the laser beam (off) off. The method of claim 1, (d) When the position coordinate enters the start area, the start area pass index is set to 1, and when the start area pass index is set to 1, the position coordinate is out of the irradiation area and exists in the end area. Setting the start area pass index to 0 in a second step; More, And the control unit turns on the laser beam only when the position coordinate is present in the irradiation area while the start area pass index is set to 1. The method of claim 2, And the start area, the irradiation area, and the end area are set to the limits of the coordinate range where processing defects do not occur in the workpiece. The method of claim 3, And the irradiation area comprises at least a part of a processing line connecting the start point and the end point by a straight line or a curve. The method of claim 4, wherein And the irradiation area partially overlaps at least one of the start area and the end area. The method of claim 4, wherein And the irradiation area does not overlap any one of the start area and the end area. The method according to any one of claims 1 to 6, And the start area, the irradiation area, and the end area are set by a vision head provided to capture a vision image of a workpiece. The method of claim 7, wherein In the step (b), the laser beam control method characterized in that the relative movement of the laser head and the table is converted into an electrical signal and the amount of change is counted.

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