JP7399702B2 - laser processing equipment - Google Patents

Description

The present invention relates to a laser processing apparatus having a galvano scanner that scans laser pulses from a laser oscillator in two-dimensional directions.

In the above galvano scanner, the accuracy of positioning to a target position may deteriorate due to past scanning history.
For example, if a movement command is given to the galvano scanner in which the rotation direction of the galvano motor included in the galvano scanner remains the same several times in a row, the rotation direction of the galvano motor included in the galvano scanner is given to the galvano scanner. I know it can get worse.
In addition, if the rotation direction of the galvano motor included in the galvano scanner is the same several times in a row, and a movement command is given to the galvano scanner that causes the cumulative total of these rotation angles to exceed a predetermined value, There may be cases where overshoot occurs and the accuracy of positioning to the target position deteriorates.
For example, the technique disclosed in Patent Document 1 improves positioning accuracy, but does not take into account the problem that positioning accuracy to a target position deteriorates due to past scanning history.

Japanese Patent Application Publication No. 2014-149406

Therefore, an object of the present invention is to improve the accuracy of positioning the galvano scanner to a target position in a laser processing apparatus having a galvano scanner that scans laser pulses from a laser oscillator in two-dimensional directions.

Among the inventions disclosed in this application, a typical laser processing device includes a galvano scanner that rotates a reflecting mirror using a galvano motor and scans laser pulses from a laser oscillator in two-dimensional directions, and a drive current that is supplied to the galvano motor. a current pattern memory that stores a plurality of time displacement patterns in which the drive current shows changes in the drive current from startup to stop of the galvano motor , and in which changes in the drive current differ over time; a current pattern correction section that reads out from the current pattern storage section and corrects a time change pattern specified by the operation command to the galvano scanner among the plurality of time displacement patterns ; and counting means for counting the number of times the rotation direction of the galvano motor continues in the same direction based on a time change pattern, and when a count value of the counting means reaches a predetermined value in a new operation command, the current pattern is stored. The current pattern correction section is characterized in that the time displacement pattern read from the section is reduced and the current pattern correction section corrects it so that the drive current becomes weaker .

The typical features of the invention disclosed in this application are as described above, but features not explained here are explained in the detailed description of the invention described later, and the features in the patent claims are As shown in the range.

According to the present invention, in a laser processing apparatus having a galvano scanner that scans laser pulses from a laser oscillator in two-dimensional directions, it is possible to improve the accuracy of positioning the galvano scanner to a target position.

5 is a flowchart for explaining processing in a current pattern correction section in Example 1 of the present invention. 1 is a schematic configuration diagram of a laser processing apparatus according to a first embodiment of the present invention. 3 is a diagram for explaining the configuration of a galvano control section in FIG. 2. FIG. 3 is a diagram showing current patterns stored in a current pattern storage section in FIG. 2. FIG. It is a flowchart for explaining the processing in the current pattern correction section in Example 2 of the present invention.

Example 1 of the present invention will be described below.
FIG. 2 is a block diagram of a laser processing apparatus according to a first embodiment of the present invention. Each component and connection line mainly shows what is considered necessary for explaining this embodiment, and does not necessarily show everything necessary for the laser processing apparatus.
The laser processing device here is for drilling holes in a printed circuit board, but the present invention is not limited thereto, and may be a laser processing device that processes multiple locations on a workpiece using laser pulses.

In FIG. 2, the laser processing apparatus includes a laser irradiation unit 2 that irradiates a printed circuit board 1 with a laser pulse emitted from a laser oscillator (not shown), and an overall control section 3 that controls the operation of the entire apparatus.
The inside of the laser irradiation unit 2 includes a galvano scanner 4 that deflects the laser pulse in two-dimensional directions, a condenser lens 5 that irradiates the laser pulse from the galvano scanner 4 to the drilling position of the printed circuit board 1, and the like.
The overall control section 3 is configured mainly of, for example, a program-controlled processing device, and is provided with a galvano control section 6 for controlling the galvano scanner 4 and the like.

The galvano control section 6 has a configuration as shown in FIG.
That is, the galvano control section 6 includes a galvano command receiving section 10 that receives galvano movement commands Cg continuously given within the overall control section 3, and a galvano motor 11 included in the galvano scanner 4 for rotating the reflecting mirror. It includes a galvano drive circuit 12 that generates a drive current for driving, and a galvano drive control section 13 that controls the galvano drive circuit 12 based on a galvano movement command Cg received by a galvano command reception section 10.

The galvano drive control unit 13 includes a current pattern storage unit 14 that stores the time displacement pattern designated by each galvano movement command Cg, and corrects the time displacement pattern read from the current pattern storage unit 14 and provides the corrected time displacement pattern to the galvano drive circuit 12. It includes a current pattern correction section 15. An encoder 16 is provided inside the galvano scanner 4 to detect the rotation angle of the galvano motor 11 and send a feedback signal to the galvano drive control section 12.
The galvano motor 11 included in the galvano scanner 4 is provided with two types: an X system for moving the scanning position in the X direction on the printed circuit board 1, and a Y system for moving the scanning position in the Y direction. Therefore, although omitted in FIG. 3, it is assumed that the galvano drive circuit 12, the galvano drive control section 13, and the encoder 16 are provided corresponding to the X system and the Y system, respectively.

The time displacement pattern stored in the current pattern storage unit 14 indicates the waveform of the drive current given from the galvano drive circuit 12 according to the rotation angle of the galvano motor 11, and the waveform is, for example, as shown in FIG. It is something.
That is, it is a pattern represented by the change in drive current from start to stop of the galvano motor 11, that is, the drive current values P1, P2, P3, . . . corresponding to each time. The periods T of the respective time displacement patterns stored in the current pattern storage section 14 are all the same length, and only the drive current values P1, P2, P3, . . . are different.

The current pattern correction section 15 converts the drive current values P1, P2, P3, . . . in the time displacement pattern read from the current pattern storage section 14 at a specified ratio. For example, when reducing the size to 85%, each of the drive current values P1, P2, P3, etc. becomes 85%, and the drive current can be weakened. Furthermore, when expanding to 125%, the drive current values P1, P2, P3, etc. each become 125%, and the drive current can be strengthened.
FIG. 1 is a flowchart for explaining the processing in the current pattern correction section 15.
In the current pattern correction unit 15, when a newly accepted galvano movement command Cg is accepted by the galvano command reception unit 10 (step 1), the rotation direction of the galvano motor in the galvano movement command Cg is the same as the previous galvano movement command Cg. It is determined whether the direction of rotation of the galvano motor 11 is the same as that in step 2 (step 2). If they are not in the same direction, the count value C of a counter (not shown) that counts rotations in the same direction is reset (step 3), and the time displacement pattern read from the current pattern storage section 14 is output as is to the galvano drive circuit 12. (Step 4).
Note that the counter is provided inside the galvano drive control section 13.

If it is determined in step 2 that they are in the same direction, the count value C of the counter is incremented by 1 (step 5), and it is determined whether this count value C has reached a predetermined value Cm (step 6). Here, if the count value C has not reached the predetermined value Cm, the time displacement pattern read from the current pattern storage section 14 is output as is to the galvano drive circuit 12 (step 4).
On the other hand, if the count value C has reached the predetermined value Cm in step 6, the count value C of the counter is reset (step 7), and the time displacement pattern read from the current pattern storage section 14 is reduced by a predetermined ratio. and outputs it to the galvano drive circuit 12 (step 8).

According to the first embodiment described above, when a movement command is given to the galvano scanner 4 such that the rotation direction of the galvano motor 11 included in the galvano scanner 4 is the same several times in succession, the rotation direction of the galvano motor 11 included in the galvano scanner 4 is given to the galvano scanner 4. If there is a hysteresis characteristic that occurs, the read time displacement pattern of the drive current of the galvano motor 11 is reduced and the drive current is weakened, so overshoot can be suppressed and the accuracy of positioning the galvano scanner 4 to the target position can be improved. It becomes possible.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the processing in the current pattern correction section 15 described in FIG. 1 is changed as shown in the flowchart in FIG.
In the current pattern correction unit 15, when a newly received galvano movement command Cg is received by the galvano command reception unit 10 (step 21), the rotation direction of the galvano motor 11 in accordance with the galvano movement command Cg is the same as the previous galvano movement command. It is determined whether the rotation direction of the galvano motor 11 is the same as that at Cg (step 22). If they are not in the same direction, the contents of a cumulative total register (not shown) that stores the cumulative total of rotation angles so far are reset (step 23), and the time displacement pattern read from the current pattern storage section 14 is directly used by the galvano drive circuit. 12 (step 24).
Note that the cumulative total register is provided inside the galvano drive control section 13.

If it is determined in step 22 that they are in the same direction, the rotation angle of the galvano motor 11 with the new galvano movement command Cg is added to the contents of the cumulative total register to obtain a new cumulative angle θs (step 25). It is determined whether the new cumulative angle θs has reached a predetermined value θm (step 26). If the predetermined value θm has not been reached here, the time displacement pattern read from the current pattern storage section 14 is output as is to the galvano drive circuit 12 (step 24).
On the other hand, if the contents of the cumulative total register have reached the predetermined value θm in step 25, the contents of the cumulative total register are reset (step 27), and the time displacement pattern read from the current pattern storage section 14 is reduced by a predetermined ratio. and outputs it to the galvano drive circuit 12 (step 28).

According to the second embodiment described above, the galvano scanner 4 receives a movement command in which the direction of rotation of the galvano motor 11 included in the galvano scanner 4 is the same several times in succession, and the cumulative total of these rotation angles exceeds a predetermined value. 4, if there is a characteristic that overtravel occurs compared to the target position, the time displacement pattern of the drive current of the galvano motor 11 is reduced and the drive current is weakened, so overshoot can be suppressed, and the target position of the galvano scanner 4 can be suppressed. It becomes possible to improve the positioning accuracy.

Although the present invention has been specifically described above based on the embodiments, it goes without saying that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the gist thereof. , including various modifications.
For example, the current pattern correction unit 15 in the first and second embodiments reduces the time displacement pattern of the drive current in response to a new operation command and weakens the drive current based on the rotation history such as the rotation direction and rotation angle of the galvano motor 11. However, based on the rotation history such as past rotation direction and rotation angle, the time displacement pattern is not only reduced to weaken the drive current, but also corrected to expand the time displacement pattern and strengthen the drive current. You can do it like this.
In this way, if there is a characteristic that the target position is not reached, the drive current is strengthened, so that it is possible to improve the accuracy of positioning the galvano scanner 4 to the target position.

Further, the current pattern correction unit 13 corrects the time displacement pattern read out based on the past rotational direction of the galvano motor 11, but may also perform correction from other viewpoints.
That is, if the current pattern correction unit 15 is able to reduce or enlarge the time displacement pattern read from the current pattern storage unit 14 at an arbitrary rate, the number of types of time displacement patterns stored in the current pattern storage unit 14 can be reduced. The storage area of the current pattern storage section 14 can be saved.

1: Printed circuit board, 2: Laser irradiation unit, 3: Overall control section,
4: Galvano scanner, 6: Galvano control unit, 10: Galvano command reception unit,
11: Galvano motor, 12: Galvano drive circuit, 13: Galvano drive control section,
14: Current pattern storage unit, 15: Current pattern correction unit, 16: Encoder

Claims (2)

A laser processing device including a galvano scanner that rotates a reflecting mirror by a galvano motor and scans a laser pulse from a laser oscillator in a two-dimensional direction, and a drive circuit that supplies a drive current to the galvano motor,
a current pattern storage unit that stores a plurality of time displacement patterns that indicate changes in the drive current from startup to stop of the galvano motor and that vary in changes in the drive current over time ;
a current pattern correction unit that reads out from the current pattern storage unit and corrects a time change pattern specified by an operation command to the galvano scanner among the plurality of time displacement patterns;
Counting means for counting the number of times that the rotation direction of the galvano motor continues in the same direction based on the time change pattern specified by the operation command,
When the count value of the counting means reaches a predetermined value in response to a new operation command, the current pattern correction section corrects the time displacement pattern read out from the current pattern storage section so that the drive current weakens. A laser processing device characterized by: A laser processing device including a galvano scanner that rotates a reflecting mirror by a galvano motor and scans a laser pulse from a laser oscillator in a two-dimensional direction, and a drive circuit that supplies a drive current to the galvano motor,
a current pattern storage unit that stores a plurality of time displacement patterns that indicate changes in the drive current from startup to stop of the galvano motor and that vary in changes in the drive current over time ;
a current pattern correction unit that reads out and corrects a time change pattern specified by an operation command to the galvano scanner from the current pattern storage unit among the plurality of time displacement patterns;
a cumulative means for calculating a cumulative value of rotation angles when the rotation direction of the galvano motor continues in the same direction based on the time change pattern specified by the operation command;
When the cumulative value reaches a predetermined value in a new operation command , the current pattern correction unit corrects the time displacement pattern read from the current pattern storage unit so that the drive current weakens. Characteristic laser processing equipment.

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