JP4670911B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus that performs processing such as drilling or marking on a workpiece using laser light.

  In recent years, a laser processing apparatus is frequently used for drilling so as to cope with diversification of processing materials and improvement of productivity of multilayer buildup substrates. In addition, there are a wide variety of machining holes required, and there is an increasing need to draw various figures from simple circles to triangles or rectangles.

  In the conventional laser processing method, the position command coordinates given to a scanning device such as a galvano scanner that performs positioning of laser light are accurately displayed in order to accurately draw curved characters, symbols, figures, etc. The correction point data generated based on the above is distributed in a virtual curve shape bulging outward from the normal curve, the drive device is positioned, and the position is irradiated with laser light.

  Further, the virtual curve correction point is located on an extended line connecting two adjacent points to form virtual curve coordinates.

  FIG. 11 shows the conventional laser processing method, wherein 111 is a corrected command point on the virtual curve, 112 is a command point before correction, and 113 is a command path curve before correction. Corresponds to the actual movement path of the galvano scanner.

  Reference numeral 114 denotes a path of the corrected command point, which corresponds to a certain virtual curve that bulges outward.

  The operation of the laser processing method configured as described above will be described. In this processing apparatus, a laser beam is scanned in a two-dimensional direction using a galvano scanner on a workpiece and an arbitrary character, symbol, figure or the like is drawn.

  However, the galvano scanner may not be able to draw an accurate position with respect to generally commanded coordinate data. This is because a follow-up delay occurs in the driving of the scanner, and a behavior delay time is required until the laser beam irradiation point starts to move from the stop state. For this reason, an internal phenomenon may occur when a curve is drawn.

  Conventionally, as shown in FIG. 11, the coordinate data of the correction points distributed on the virtual curve swelled outside the normal curve as shown in FIG. 11 is generated based on the behavior delay time of the galvano scanner. I was drawing.

Further, the correction point is located in an extended line connecting two adjacent points, and the coordinates of a point that is separated from the teaching side of the two points by a distance determined based on the behavior delay time and the machining speed. Data was generated as coordinate data of correction points.
Japanese Patent Laid-Open No. 2001-225181 (FIG. 3)

However, the conventional laser processing method requires an arithmetic circuit for calculating the behavior delay time of the galvano scanner in order to obtain the coordinate data of the correction points distributed on the virtual curve swelled outside the normal curve. It was.

  For this reason, the behavior delay time requires an angle sensor as a means for detecting an angle from a signal obtained from the servo circuit of the galvano scanner, and a differentiation circuit as a means for detecting a speed. Further, the state is determined from these data. This can be achieved by a combination of means such as a comparator.

  An operation command can be given to the galvano scanner only after the correction point data is generated by a memory that stores the detected behavior delay time, a CPU that calculates the data, or the like.

  Therefore, in order to realize this laser processing method, it is necessary to precisely design these control circuit units, and there is a problem that the laser irradiation position does not fall within the specified range when processing that requires high accuracy is performed. Was.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laser processing apparatus that can accurately draw an arbitrary character / symbol / graphic including a curve.

In order to achieve the above object, a laser processing apparatus according to the present invention is based on a driving unit that scans and moves a laser beam with a galvano scanner, a galvano scanner driver that controls the galvano scanner, and a signal in the galvano scanner driver. A rotation radius calculation means for reading the current coordinates of the galvano scanner and calculating a rotation radius for scanning the laser beam; and a control means for generating a laser output waveform for irradiating a laser pulse,
The laser is started when the value calculated by the turning radius calculation means becomes smaller than a predetermined value set in advance , and the laser irradiation is ended when the value becomes larger than the predetermined value again .

  As described above, according to the present invention, it is possible to perform high-accuracy processing capable of realizing accurate drawing by irradiating laser light only when the laser irradiation position is within the prescribed range of the normal curve.

Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS.
(Reference Example 1)
FIG. 1 shows a correction position of coordinate data and an actual laser irradiation position when circular drawing is performed in a reference example of the present invention. Reference numeral 11 denotes a corrected command coordinate point, 12 denotes a corrected second point of the command coordinate, 13 denotes an actual laser irradiation point, 14 denotes an actual galvo movement path, and 15 denotes a command path given to the galvano. .

  The operation of the laser processing method configured as described above will be described.

  The actual laser irradiation point 13 is corrected to a normal position by giving data to the galvano scanner using the points 11 and 12 having a large radius 15 outside the path 14 to be processed by irradiating the laser as command coordinates. The

  Further, in order to make up for the shortage of machining due to the delay in tracking of the galvano scanner, a point 12 on the second round is added, so that the laser irradiation point is again at the position of the machining start point after one round from the position of the machining start point. When the laser beam returns, the laser irradiation is finished, and the laser processing for circular drawing can be completed.

  By the way, when the laser irradiation is performed without performing the coordinate correction as described above, the operation is as shown in FIG.

  FIG. 2 shows a locus of a laser irradiation point when circular drawing is performed by a general position command without coordinate correction. Looking at the irradiation position of the laser, it can be seen that the point gradually moves inward from the irradiation position from the processing start point, and the irradiation is performed with a certain radius from the fourth point to the final point.

  Thus, there is a difference between the radii of the galvano movement path 14 and the galvano command path 15 which are actual laser irradiation points. This is generally referred to as radius reduction, and desired processing cannot be performed due to the effect of radius reduction.

  Further, although the end point of the command point 11 coincides with the machining start point, the actual laser irradiation point 13 has completed irradiation at a position before the end point. That is, there is an insufficiently processed part, which also causes a desired process to not be performed.

  FIG. 3 shows a configuration example of a laser processing apparatus according to a reference example of the present invention, in which 31 is a means for transmitting processing data such as coordinate points, 32 is a laser oscillator for emitting laser light, and 33 is for scanning laser irradiation in a two-dimensional direction. In this case, the galvano scanner 34 is a laser beam inclined at an arbitrary angle, and the fθ scan lens 35 outputs laser light in the vertical direction. The workpiece 36 is a processing hole formed by laser irradiation. It is a table on which the workpiece 35 is placed, and has a mechanism that can move horizontally in both the X and Y directions.

  The operation of the laser processing apparatus configured as described above will be described.

  First, a hole position coordinate is read from a machining program used in an NC apparatus or the like, and a control command, a machining hole coordinate, laser control data, or the like is machined to the machining data transmission control unit 31 that the controller transmits to the machining table 37 or the galvano scanner 33. Send data.

  The processing data transmission control unit 31 transmits data to the XY table control unit, the laser output control unit, and the galvano scanner driver, depending on the data type of the processing data.

  The control means controls the processing table 37, the laser oscillator 32, and the galvano scanner 33 in synchronization with each other.

  Then, the laser beam scanned in an arbitrary angle direction by the galvano scanner 33 is adjusted so that the fθ scan lens 34 changes the vertical direction and the laser beam is condensed by the workpiece 35, and a machining hole is formed on the workpiece 35. Is formed.

  In order to perform coordinate correction as shown in FIG. 1, it is necessary to pass the correction coordinate data to the processing data transmission control unit 31 before transmitting the processing data.

  FIG. 4 shows a correction coordinate calculation processing method. When data of an arbitrary machining shape and laser oscillation conditions are given, correction calculation is performed by this method, and the corrected data is passed to the controller.

  First, when processing is started, a processing speed is derived from given processing shape data and laser oscillation conditions.

  The processing speed is obtained by dividing the distance between laser irradiation points obtained from the processing shape data by the point-to-point movement time obtained from the laser oscillation conditions.

  Furthermore, by dividing this machining time by the radius of the curve, it can be parameterized as a velocity at an arbitrary radius of curvature. In the present invention, this is defined as “speed parameter”, and this calculation processing corresponds to the calculation of the speed parameter, which is the first step in FIG.

  Then, the process proceeds to the next step. Here, a storage unit called an internal storage 1 is used in which an expansion coefficient for a speed parameter obtained in advance by experiments is stored as data.

  The enlargement factor is the ratio of the diameter D1 of the galvano movement command path to the diameter D0 of the actual laser pulse irradiation path shown in FIG. 1, and has a relation of enlargement coefficient = D1 / D0. The table of the internal memory 1 in FIG. 4 shows actual values as an example. From the above, the value of the enlargement factor is calculated.

  In the next step, the diameter of the corrected hole is calculated.

  It can be obtained by multiplying the enlargement factor obtained in the previous step by the machining hole diameter before correction.

  For example, if the processed hole diameter before correction is D and the enlargement factor is k, the corrected processed hole diameter D ′ is D ′ = k × D.

  Thus, the corrected machining hole diameter is obtained, and the coordinates of the correction command point 11 shown in FIG. 1 can be generated.

  Next, a method for calculating coordinates for overlapping command points in order to compensate for an insufficient machining portion will be described.

  First, the speed parameter is recalculated by the above method based on the corrected machining hole diameter calculated in the previous step, and the overlap angle is obtained from the value by the same method as the calculation of the corrected machining hole diameter. .

  Coordinate points will be added by this angle.

  4 shows an example of an actual overlap angle with respect to the speed parameter.

  As described above, two correction data of the surrounding hole diameter and overlap angle are calculated, all coordinate data of the command point of the next step is created, and all coordinate data is transmitted to the machining data transmission control unit 31 to complete the processing. .

  Note that this correction process and internal storage implementation method may use an electronic circuit such as a CPU or memory, or may perform all the processes using software.

  In Reference Example 1 of the present invention, correction processing is performed using software, which can be easily realized.

  FIG. 5 and FIG. 6 show experimental data used in the correction calculation. FIG. 5 is based on the enlargement factor, and FIG. 6 is based on the overlap angle. The value for the speed parameter can be read.

  As described above, the laser processing apparatus relates to a method for obtaining a correction amount from an enlargement coefficient corresponding to a speed parameter and controlling a laser pulse irradiation position.

  Further, in order to realize the above correction method, a laser processing apparatus provided with a means for storing an enlargement coefficient or a means for calculating a correction amount.

Further, in order to realize the above correction method, there is a method for providing a means for storing an overlap angle, and a laser processing apparatus provided with a means for calculating a correction amount.
(Embodiment 1)
FIG. 7 is a diagram illustrating the timing of monitoring the laser irradiation position and irradiating the laser pulse only when the radius of curvature is within a specified range.

  As shown in FIG. 2, the laser beam deviates from a desired path and travels inward until a certain time from the start of laser irradiation. The time passage from the radius R1 to Rn of each point at that time is shown in the graph of FIG.

  The radius gradually decreases from R1 to R3, and from there to a constant radius (radius stable region). In order to determine whether the state is stable at this constant radius, a value of the radius Rt at the time of stable operation is set, and if the radius R at a certain point is smaller than Rt, the value is stable (in the radius stable region). )

  Therefore, laser irradiation starts at the moment (Ts) when R <Rt changes from false to true, and laser irradiation ends at the moment (Te) when it changes again from false.

  Thereby, the pulse can be irradiated only when the laser irradiation position is on a desired path, so that laser processing to an accurate position is possible. The laser processing apparatus controls the laser irradiation pulse as described above.

FIG. 8 shows an apparatus configuration for realizing the laser irradiation start / end control. 81 is a means for calculating a radius, 82 is a means for determining a stable operation, and 83 is a means for performing laser irradiation command control.

  First, in order to know the laser irradiation position at a certain time, it is possible to take out a signal in the galvano scanner driver.

  As shown in FIG. 8, the current position of the XY coordinates of the galvano scanner is read by the X-axis feedback signal and the Y-axis feedback signal, and the radius is calculated by the turning radius calculation means 81.

Since the radius R can be obtained by R = (X ² + Y ² ) ^1/2 , an arithmetic circuit for performing this may be provided.

  Then, as a means for determining the stable operation determination condition R <Rt, the stable operation determination means 82 makes a true / false determination. This can be realized by providing a comparator.

  Based on this result, the laser irradiation command control means 83 performs laser irradiation ON / OFF control. This is because a gate circuit is provided separately, the gate signal is switched to High by a laser irradiation ON command, the gate signal is switched to Low by a laser irradiation OFF command, and an AND circuit is provided between the original laser pulse command signal This can be achieved.

  As a result, a signal in which the timing of starting and ending irradiation is controlled is sent to the laser output control unit, and the laser can be irradiated only when the driving operation of the galvano scanner is in a stable state.

The laser processing apparatus controls the laser irradiation pulse as described above.
(Reference Example 2)
FIG. 9 is a diagram showing a method for setting a laser irradiation point when the number of rotations of laser irradiation is two or more.

  In the figure, 91 is a command point for the first and third rounds, and 92 is a command point for the second and fourth rounds. The command point 92 for the second and fourth laps is set at the midpoint position between the command points 91 for the first and third laps, and the command point 91 for the third lap is the command for the second and fourth laps. This is set at the midpoint position between the points 92.

  First of all, by increasing the number of times of laser irradiation, there is an effect of reducing the work piece from being burned out due to the heat effect of the laser irradiation.

  Next, by setting the laser irradiation point during the previous round, there is an effect of reducing the above-mentioned thermal influence by distributing the laser irradiation energy in a balanced manner without being shifted to one place.

  This realization method can use the apparatus configuration described in Reference Example 1 as it is. The laser processing apparatus includes an arithmetic circuit that generates the command points as described above.

  FIG. 10 is a diagram showing a method of setting a laser irradiation point when the number of rotations of laser irradiation is two times or a plurality of times, and particularly an example of the case of three rotations.

  In the figure, 101 is a command point for the first turn, 102 is a command point for the second turn, and 103 is a command point for the third turn. The command point 102 for the second lap and the command point 103 for the third lap are set at positions obtained by dividing the point of the command point 101 for the first lap into three.

  This method is a method of dividing N points between the command points 101 in the first round when performing N rotations. The effect is equivalent to the above. The apparatus configuration is also equivalent to the above.

  This is a laser processing apparatus that generates command points as described above.

  The laser processing apparatus corrects the irradiation position of the laser beam and controls the irradiation start position of the laser pulse.

  Further, the laser processing apparatus corrects the irradiation position of the laser beam, and when the relative movement between the laser beam and the workpiece includes a curve or a circle and the number of rotations is a plurality of times of two or more rounds, the second and subsequent rounds are performed. The irradiation position is set.

  Further, the laser processing apparatus corrects the irradiation position of the laser beam, the relative movement between the laser beam and the workpiece includes a curve or a circle, and the number of rotations of the laser beam and the workpiece does not overlap all the irradiation points at a plurality of times. In this case, the irradiation positions after the second round are set.

  Further, the laser processing apparatus corrects the irradiation position of the laser beam, controls the irradiation start position of the laser pulse, and further, the relative movement of the laser beam and the workpiece includes a curve or a circle, and the number of rotations thereof is two rounds. In the case of the above plural times, the irradiation positions after the second round are set by the method according to claim 6.

  Further, the laser processing apparatus corrects the irradiation position of the laser beam, controls the irradiation start position of the laser pulse, and further, the relative movement between the laser beam and the workpiece includes a curve or a circle, and the number of rotations thereof is 3 times. When all the irradiation points are not overlapped by the above plural times, the irradiation positions after the second round are set.

  The laser processing apparatus of the present invention can process an accurate shape and is industrially useful in the laser processing field and the like.

The coordinate correction method figure in the reference example 1 of the laser processing apparatus of this invention General operation diagram in Reference Example 1 of laser processing apparatus of the present invention Apparatus configuration diagram in Reference Example 1 and Embodiment 1 of the laser processing apparatus of the present invention Correction amount calculation processing diagram in Reference Example 1 of the laser processing apparatus of the present invention Experimental data diagram of magnification factor in Reference Example 1 of the laser processing apparatus of the present invention Experimental data diagram of overlap angle in Reference Example 1 of laser processing apparatus of the present invention Irradiation timing chart in Embodiment 1 of the laser processing apparatus of the present invention The apparatus block diagram in Embodiment 1 of the laser processing apparatus of this invention Coordinate command point diagram in Reference Example 2 of laser processing apparatus of the present invention Coordinate command point diagram in Reference Example 2 of laser processing apparatus of the present invention Coordinate correction method diagram of conventional laser processing equipment

Explanation of symbols

11 Correction command point 12 Second rotation correction command point 13 Laser irradiation point 14 Actual galvano movement path 15 Galvano command path 31 Processing data transmission control unit 32 Laser oscillator 33 Galvano scanner 34 fθ scan lens 35 Work piece 36 Processing hole 37 Processing Table 81 Rotation Radius Calculation Unit 82 Stable Operation Determination Unit 83 Laser Irradiation Command Control Unit 91 First and Third Round Correction Command Point 92 Second and Fourth Round Correction Command Point 101 First Round Correction Command Point 102 Correction command point for second lap 103 Correction command point for third lap

Claims (1)

Drive means for scanning and moving the laser beam with a galvano scanner ;
A galvano scanner driver for controlling the galvano scanner;
A turning radius calculating means for reading a current coordinate of the galvano scanner based on a signal in the galvano scanner driver and calculating a turning radius for scanning the laser beam;
Comprising a control means for generating a laser output waveform for irradiating a laser pulse;
The control means is configured to start laser irradiation after the value calculated by the turning radius calculation means becomes smaller than a predetermined value set in advance and to end laser irradiation when the value becomes larger than the predetermined value again. Laser processing equipment that performs laser pulse irradiation.