JP2023050541A - Laser processing device - Google Patents

Abstract

To provide a laser processing device capable of processing with superior positional accuracy, during a period after activation of a laser oscillator until an optical axis position of a laser beam is stabilized.SOLUTION: A calibration amount of an optical axis position is calculated according to a positional change in an optical axis of a laser beam, for a period after activation of a laser oscillator until a prescribed time has elapsed, and stores the calibration amount in beforehand. During the period after activation of the laser oscillator until a prescribed time has elapsed, an optical axis position of a laser beam is calibrated using optical axis deflection means, on the basis of the stored calibration amount of the optical axis position.SELECTED DRAWING: Figure 5

Description

The present invention relates to, for example, a laser processing apparatus for drilling holes in a printed circuit board using a laser. It relates to a laser processing apparatus that corrects so as to match.

In a laser processing apparatus, it is known that the optical axis position of the laser output from the oscillator shifts and becomes unstable for a while after the laser oscillator as a light source is started. This is because the temperature inside the laser oscillator rises when laser oscillation starts, and components such as lenses, mirrors, and brackets supporting them are thermally deformed. It is known that the optical axis position stabilizes when the components are thermally saturated.

In order to cope with such an optical axis positional deviation, a laser processing apparatus having an optical axis deflecting means, such as that disclosed in Patent Document 1, is known. FIG. 1 is an explanatory diagram schematically showing an optical path system of a laser processing apparatus having a conventional optical axis deflecting means, and FIG. 2 is a diagram explaining the operation of the conventional optical axis deflecting means. A conventional laser processing apparatus will be described with reference to FIGS. 1 and 2. FIG.

As shown in FIG. 1, a conventional laser processing apparatus includes a laser transmitter 1, an optical axis deflecting means 10, an external optical system 2, an optical axis positioning means 30, a condensing lens (fθ lens) 3, first and second It comprises splitters 22 , 24 , first and second optical axis position detection sensors 21 , 23 , and table 5 .

A laser beam emitted from a laser oscillator 1 is guided to an optical axis deflecting means 10 composed of a plurality of mirrors, etc., and an external optical system 2 composed of mirrors, lenses, etc. The light enters the optical axis positioning means 30 and enters the workpiece 4 fixed on the table 5 via the condensing lens (fθ lens) 3 . The external optical system 2 is arranged so that its axis is coaxial with the basic optical axis O. As shown in FIG. The basic optical axis O is an optical axis that coincides with the center of the opening (emission part) of the laser oscillator and is perpendicular to the opening.

The optical axis positioning means 30 is composed of galvanometer mirrors 31 and 32 whose rotation axes are twisted, and scanner motors 33 and 34 for rotating the galvanometer mirrors 31 and 32. They are arranged so that their axes are perpendicular to the basic optical axis O. By rotating the galvanometer mirrors 31 and 32, the laser beam is positioned at a desired position on the workpiece 4. FIG. The table 5 is configured to be movable in the XY directions (left and right directions of the paper and vertical directions of the paper).

Further, first and second splitters 22 and 24 for splitting the laser light are provided between the optical axis deflection means 10 and the optical axis positioning means 30 to detect the first and second optical axis positions of the split laser light. The light enters the sensors 21 and 23 and detects the positions of the respective optical axes. Both optical axis position detection sensors 21 and 23 have a large number of minute light receiving elements arranged on their surfaces in a plane direction perpendicular to the detection beam (when the incident laser light is on the basic optical axis O). , and the detection center is positioned on an extension of the basic optical axis O.

The first and third mirrors 11 and 14 constituting the optical axis deflecting means 10 provided between the laser oscillator 1 and the external optical system 2 have their rotation axes perpendicular to the basic optical axis O. and parallel to the axis of the workpiece and movable in a direction toward or away from the basic optical axis O (that is, a direction corresponding to the XY directions on the surface of the workpiece).

The first mirror 11 has an axis 12 perpendicular to the direction in which the laser beam is incident (perpendicular to the paper surface), and is rotatable about the axis 12 in the direction of the arrow UU', A moving device (not shown) is used to move the Z-axis direction perpendicular to the basic optical axis O (the direction of the arrow ZZ', the Y-axis direction on the surface of the workpiece 4 and the vertical direction of the paper surface) (that is, the basic light It is movable in a direction parallel to an axis perpendicular to the axis O and in a direction toward and away from the basic optical axis O). Also, the reference angle of the first mirror 11 with respect to the basic optical axis O is 45°. The second mirror 13 deflects the basic optical axis O deflected by the first mirror 11 perpendicularly to the plane of the paper and in the depth direction of the plane of the paper.

The third mirror 14 has an axis 15 perpendicular to the direction of incidence of the laser light (parallel to the paper surface), and is rotatable about the axis 15 in the direction of the arrow VV', It is movable in a direction perpendicular to the plane of the drawing (that is, in a direction parallel to an axis perpendicular to the basic optical axis O and in a direction toward or away from the basic optical axis O) by a moving device (not shown). The relationship between the third mirror 14 and the axis 15 when viewed from direction A in the figure is the same as the relationship between the first mirror 11 and the axis 12 in the figure, and is the reference for the basic optical axis O of the third mirror 14. The angle is 45°.

The first mirror 11 operates as follows to correct the optical axis position. As shown in FIG. 2A, when the optical axis of the laser beam 6 deviates parallel to the basic optical axis O in the Z-axis direction, the first mirror 11 is moved in the Z-axis direction to Align with axis O. Further, as shown in FIG. 2B, when the laser beam 6 is tilted by an angle α, the first mirror 11 is tilted in the U direction by an angle α so as to be parallel to the basic optical axis O, and further in the Z-axis direction. to coincide with the basic optical axis O. Furthermore, when the laser beam 6 is deviated parallel to and tilted with respect to the basic optical axis O, the angle of the first mirror 11 is changed and further moved in the Z-axis direction to match the basic optical axis O. , the deviation in the X-axis direction is eliminated. Similarly, the third mirror 14 is used to eliminate deviation in the Y-axis direction. The angle of rotation and the distance of movement of the first and third mirrors 11 and 14 can be calculated from the amount of deviation of the center of the laser light from the center of the sensor in both the optical axis position detection sensors 21 and 23. can.

JP-A-2005-205429

However, the conventional technology corrects the optical axis position while detecting it with a sensor. Therefore, there is a time lag between when the sensor detects the misalignment and when the mirror is actually operated, and the accuracy of the machining position deteriorates. There was a problem from the point of view of In addition, since processing is performed while detecting and correcting the optical axis position, if the optical axis position detection sensor fails, the optical axis position cannot be corrected and the machining must be interrupted.

Therefore, the present invention solves the above-mentioned problems, immediately corrects the deviation of the optical axis position after starting the laser oscillator without causing the time difference, improves the positional accuracy, and prevents the optical axis position detection sensor from malfunctioning. It is an object of the present invention to provide a laser processing apparatus capable of processing while correcting the optical axis position.

In order to solve the above problems, the present inventor conducted various investigations, and as a result of examining the change in the position of the optical axis after starting the laser oscillator until the position of the optical axis stabilizes, the laser oscillation conditions (repetition of the laser It was found that the optical axis position changes almost similarly for each frequency and pulse width. In other words, the inventors have found that the change in the position of the optical axis after the oscillator is started can be reproduced within the permissible range for each oscillation condition.

3 and 4 are diagrams for explaining the position change of the laser optical axis after the laser oscillator is started. FIG. 3 is a graph showing the change in the optical axis position when the Co2 pulse laser oscillator is alternately emitted under oscillation conditions 1 and 2 with different repetition frequencies and irradiation pulse widths. The horizontal axis represents the elapsed time, and the vertical axis represents the coordinates of the optical axis position. (A) shows the position change of the X-axis and (B) shows the position change of the Y-axis by the optical axis position detection sensor. Note that the oscillator was stopped and started each time the oscillation conditions 1 and 2 were switched, but since the laser was not irradiated during the stop, the data during the stop time was omitted in consideration of the visibility of the graph.

FIG. 4 shows a laser processing apparatus different from the laser processing apparatus in which the data in FIG. 3 was measured. FIG. 3 is a graph showing the change in the position of the optical axis when the beam is emitted to . Similar to FIG. , data during oscillation condition switching are omitted. Oscillation conditions 3 and 4 differ in repetition frequency and irradiation pulse width.

In addition, in the condition 1 of FIG. 3 and the condition 3 of FIG. 4, the measurement was made longer by the measurement time immediately after the start (about 30 minutes). This is to show that the position change is the largest for a while after the oscillator is started, and then the optical axis position stabilizes. After the condition change, the graph was made using only the data for a short time (each measurement time is the same) until the optical axis position stabilizes.

As is clear from FIGS. 3 and 4, oscillation conditions 1 to 4 show similar position changes for each condition. Although the data in FIGS. 3 and 4 are the measurement results of the optical axis position detection sensor on the side closer to the oscillator, the optical axis position sensor on the side farther from the oscillator showed similar position changes under each condition.

From FIGS. 3 and 4, it can be seen that the position change after the laser oscillator is started until the position of the laser optical axis stabilizes is the same for each oscillation condition. It is believed that this is because the optical components inside the oscillator and the brackets that support them go through a similar change process for each laser oscillation condition until they reach a thermally saturated state.

Based on the above findings, a representative laser processing apparatus among the inventions disclosed in the present application is as follows in order to solve the above problems. A laser in which an optical axis positioning means is arranged on a predetermined optical axis of a laser beam output from a laser oscillator, and the laser beam output from the laser oscillator is positioned on a workpiece by the optical axis positioning means A processing apparatus comprising: optical axis deflection means disposed between the laser oscillator and the optical axis positioning means and capable of deflecting the optical axis of the laser beam; and the optical axis positioning means and the optical axis deflection means. and an optical axis position detection means for detecting the position of the optical axis of the laser beam, and further comprising a predetermined time after the activation of the laser oscillator detected by the optical axis position detection means. for aligning the optical axis of the laser beam incident on the optical axis positioning means with the predetermined optical axis by the optical axis deflection means based on the change in the optical axis position of the laser beam until the time elapses a correction amount calculation unit that calculates a correction amount; and a correction information storage unit that stores the calculated correction amount, the optical axis deflection based on the correction amount stored in the correction information storage unit characterized in that the means deflects the optical axis of the laser light

According to the present invention, laser processing can be performed with high positional accuracy immediately after starting the processing apparatus, and production efficiency can be improved. Moreover, even if the optical axis position detection sensor fails during processing, processing can be continued while correcting.

FIG. 10 is an explanatory diagram schematically showing an optical path system of a conventional laser processing machine having an optical axis position correcting function; It is a figure explaining operation|movement of the conventional optical-axis position correction unit. FIG. 10 is a diagram showing changes in the optical axis position after starting the laser oscillator; FIG. 10 is a diagram showing changes in the optical axis position after starting the laser oscillator; 1 is a block diagram of a laser processing apparatus according to an embodiment of the present invention; FIG.

A representative embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a block diagram of a laser processing apparatus that is an embodiment of the present invention. 1 or 2 are given the same reference numerals, and the description thereof will be omitted.

Reference numeral 40 denotes an overall control unit for controlling the operation of the entire apparatus, which is implemented by, for example, a program-controlled processor. The general control unit 40 includes a laser oscillation control unit 41 for outputting a laser oscillation command signal for instructing the laser oscillator 1 to oscillate a laser pulse, an optical axis deflection means control unit 42 for controlling the operation of the optical axis deflection means 10, an external It includes an external optical system control section 43 that controls the operation of the optical system 2 and an optical axis positioning means control section 44 that controls the operation of the optical axis positioning means 30 .

The overall control unit 40 further provides correction amounts (first and third A correction amount calculation unit 45 for calculating the amount of rotation and movement of the mirrors 11 and 14, and a correction information storage unit 46 for storing the calculated correction amount as correction information. Note that some of these functional elements included in the overall control unit 40 may be provided separately from the overall control unit 40 . A laser drilling device has various components and connecting lines in addition to those described here, which are omitted here.

In the above configuration, correction information for each oscillation condition (repetition frequency and irradiation pulse width) is obtained in advance as follows before drilling.

First, the general control unit 40 measures the position change of the optical axis by the first and second optical axis position detection sensors 21 and 23 until the laser optical axis stabilizes after the laser oscillator 1 is activated. In other words, the behavior of the optical axis position is measured from the start of the oscillator to the stabilization of the optical axis. The correction amount calculator 45 calculates the correction amount (the angle of rotation and the distance of movement of the first and third mirrors 11 and 14) for matching with the basic optical axis O based on the measured positional change of the optical axis. and save it in the correction information storage unit 46 . Since the change in the optical axis position of the laser after starting the oscillator differs for each oscillation condition (repetition frequency and irradiation pulse width), the change in the axis position should be measured in advance for each oscillation condition that may be used for drilling. , and the correction information for each oscillation condition is stored in the correction information storage unit 46 . Since the time required for the laser optical axis to stabilize varies depending on the oscillation conditions, this time is determined in advance by experiment.

When drilling, the optical axis deflection means control section 42 reads out the correction amount corresponding to the oscillation conditions used for machining from the correction information storage section 46, and operates the optical axis deflection means 10 based on the correction information. Let

According to the present invention, prior to processing, the optical axis position can be corrected using the correction information calculated based on the previously measured position change of the optical axis. In other words, the optical axis deflecting means can be operated in accordance with the timing when the optical axis position shifts. Therefore, there is no time lag, unlike the case where the sensor detects and corrects the deviation of the optical axis position while processing, and it is possible to prevent the deterioration of the processing accuracy.

In addition, conventionally, machining was performed while detecting and correcting the optical axis position, so if the optical axis position detection sensor failed during machining, the optical axis position could not be corrected. Since the optical axis position is not detected during the medium, correction can be continued even if the sensor fails.

It should be noted that the positional change of the optical axis after the oscillator is activated changes little by little due to aging deterioration of internal components of the laser oscillator 1 and the external optical system 2, adhesion of minute foreign matter to the optical parts, etc. Therefore, for example, machining The correction information may be updated by re-measuring changes in the position of the optical axis each time the device is used a predetermined number of times or for a predetermined period of time.

Although one embodiment of the present invention has been described above, various modifications are possible by variously replacing the constituent elements of the embodiment and adding other elements. The present invention is not limited to this embodiment, and can be applied to processes other than drilling as long as it is a process using a laser.

1: laser oscillator, 10: optical axis deflection means, 21: first optical axis position detection sensor, 23: second optical axis position detection sensor, 2: external optical system, 30: optical axis positioning means, 4: workpiece , 41: laser oscillation control section, 42: optical axis deflection means control section, 45: correction amount calculation section, 46: correction information storage section

Claims (2)

A laser in which an optical axis positioning means is arranged on a predetermined optical axis of a laser beam output from a laser oscillator, and the laser beam output from the laser oscillator is positioned on a workpiece by the optical axis positioning means A processing device,
an optical axis deflecting means disposed between the laser oscillator and the optical axis positioning means and capable of deflecting the optical axis of the laser beam;
optical axis position detection means disposed between the optical axis positioning means and the optical axis deflection means for detecting the position of the optical axis of the laser beam;
Further, the optical axis is positioned by the optical axis deflecting means based on the change in the optical axis position of the laser beam detected by the optical axis position detecting means until a predetermined time elapses after starting the laser oscillator. a correction amount calculation unit that calculates a correction amount for matching the optical axis of the laser beam incident on the means with the predetermined optical axis;
a correction information storage unit that stores the calculated correction amount,
The optical axis deflection means deflects the optical axis of the laser beam based on the correction amount stored in the correction information storage unit.
A laser processing device characterized by: wherein the correction information storage unit stores a correction amount for each oscillation condition of the laser oscillator;
2. The laser processing apparatus according to claim 1, wherein:

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