JPH07178578A - Laser beam machine - Google Patents

Abstract

PURPOSE:To control irradiation timing without generating delay in time by predicting a change in the relative position of a laser and a work piece in accordance with stored command values and controlling timing for irradiation with the laser. CONSTITUTION:The command driving values for an X-axis driving section 8 and a Y-axis driving section 9 which moves the work piece in an X-Y direction is set in a numerical value control section 10. These command values are converted to the data on the timing for the irradiation with the laser and are stored in a data buffer 22. A control section 25 for an output signal of irradiation with the laser outputs pulse signals to a laser oscillation unit 1 in accordance with the data on the timing for the irradiation with the laser outputted from this data buffer 22. The comparison of the relative moving quantity of the position to be irradiated with the laser and the work piece and the timing for the irradiation with the laser is executed without making intricate calculation and, therefore, the high speed dealing with the feedback of the relative moving quantity is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus which is connected to a numerical control apparatus (NC apparatus) to perform processing such as welding and cutting of metal and resin.

[0002]

2. Description of the Related Art Laser beams have a very high energy density and are widely used for welding, cutting and heat treating metals and resins. A general laser processing apparatus will be described with reference to FIG.

In FIG. 7, a laser processing apparatus includes a laser oscillation unit 1 that oscillates a laser beam 2, a mirror 3 that reflects the laser beam 2 and guides it to a workpiece 5, and a lens that condenses the laser beam 2. 4 and the workpiece 5 are mounted on the X
-The table 6 moving in the Y direction and the table 6 are moved to the X
Controls the X-axis drive unit 8 that moves in the axial direction, the Y-axis drive unit 9 that moves the table 6 in the Y-axis direction, the laser oscillation unit 1, the X-axis drive unit 8, and the Y-axis drive unit 9. And a control unit 7 for

In the laser processing apparatus having such a configuration, the table 6 moves based on the movement control signal from the control section 7, and the relative position between the workpiece 5 mounted on the table 6 and the laser beam 2. Changes, and the laser beam 2 is irradiated onto the workpiece 5 along the movement path to be processed.

By the way, the laser oscillation unit 1 is
The table 6 is pulse-oscillated at a constant time interval. On the other hand, the movement of the table 6 is not limited to a constant velocity movement, but also an acceleration or deceleration movement at the start and stop of the movement operation or when the movement direction is changed. It will be. Therefore, when the workpiece 5 is processed by using this type of laser processing device, the irradiation amount of the laser beam 2 per unit moving distance becomes larger in the acceleration / deceleration movement region than in the constant velocity movement region. It will be. Therefore, for processing such corners with acceleration and deceleration, the energy density is higher than that for linear moving parts that move at a constant speed, and welding and cutting that maintain uniform processing quality can be performed. There was a problem that I could not.

In order to solve the above-mentioned problems, one construction of a laser processing apparatus for obtaining a uniform processing quality by making the energy density per unit moving distance constant is disclosed in Japanese Patent Laid-Open No. 59-147792. It is disclosed in the publication.

In the laser processing apparatus disclosed in Japanese Patent Laid-Open No. 59-147792, the control unit 7 has a laser beam 2 in the configuration of the general laser processing apparatus shown in FIG.
The number of oscillation pulses of the laser oscillation unit 1 is controlled according to the amount of change in the relative position between the workpiece 5 and the workpiece 5. The specific control operation will be described with reference to FIG.

The numerical control unit 10 sends a command value for moving the table 6 to the X-axis drive unit 8 and the Y-axis drive unit 9 via the D / A converters 11 and 12, and also to the register 1
A designated value L designating the laser pulse interval is output to 7.
The encoders 13 and 14 detect the amount of movement of the table 6 from the operation of the drive units 8 and 9 for each axis, feed back the signal to the numerical control unit 10, and subtract the command values. The movement of the table 6 is continued until the command value becomes zero.

The detection signals output by the encoders 13 and 14 are respectively counted by the counters 15 and 16, and the count values are X and Y. Computing unit 18
Is before

From the count values X and Y,

## EQU1 ## This value and a designated value L for designating the laser pulse interval in the register 17 are calculated.

Compared with, the count values X and Y are

When the value that satisfies the above condition is reached, a laser output pulse signal is sent to the laser oscillation unit 1 and
The counter value is reset to 0.

Thereafter, a detection signal indicating the amount of movement of the table 6 is sent from the encoders 13 and 14 to the counters 15 and 1, respectively.
When it is transmitted to 6, the counters 15 and 16 count the signal again, and the arithmetic unit 18 repeats the above operation. The laser oscillating unit 1 includes the arithmetic unit 18
Each time the pulse signal output from the
Is output one pulse at a time.

As described above, the above-mentioned JP-A-59-1477 is used.
In the laser processing apparatus described in Japanese Patent Publication No. 92, a laser pulse is emitted every time the relative movement amount between the laser beam 2 and the non-workpiece 5 reaches a constant value L regardless of the change in the moving speed of the table 6. .

[0016]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention JP-A-59-14
In the laser processing apparatus disclosed in Japanese Patent No. 7792,
In order to determine the timing of the laser pulse, the relative moving distance between the laser beam and the non-workpiece must be calculated while the table on which the non-workpiece is placed is moving.
Therefore, after the laser irradiation position reaches a predetermined position to be irradiated, it takes a certain time to calculate the relative movement distance between the laser light and the non-processed object, and then the laser light is irradiated. Become. However, the relative positional relationship between the laser beam and the non-workpiece changed while the time required to calculate this relative movement distance passed, and it was necessary to calculate this relative movement distance. An error occurs in the irradiation position of the laser light by the amount moved during the time.

This error becomes larger as the relative speed between the non-workpiece and the laser beam becomes higher, and when the moving speed of the table changes during the processing, the laser irradiation interval deviates, and the processing quality. There was a problem that it greatly affected the.

[0018]

In order to solve the above problems, a laser processing apparatus of the present invention provides a laser oscillation unit for pulse-oscillating a laser, and a command for changing the relative position between the laser and a workpiece. A numerical control means for outputting a value, a first storage means for temporarily storing the command value, and a relative position between the laser and the workpiece based on the command value stored in the first storage means. Change in advance, and data generation means for generating laser irradiation timing data with the relative movement amount as a parameter, and the command value stored in the first storage means are read out on a first-in first-out basis, and based on the command value. Driving means for changing the relative position of the laser and the workpiece, detection means for detecting the amount of change in the relative position of the laser and the workpiece, and detection by the detecting means And a timing control means for controlling the laser irradiation timing based on the laser irradiation timing data generated in the variation between the data generating means of the relative position is.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described in detail with reference to the drawings.

The laser processing apparatus of the present invention is configured to include the configuration shown in FIG. 7 described above, and the description of the overlapping parts will be omitted.

FIG. 1 is a block diagram showing an embodiment of the control unit 7 in the laser processing apparatus of the present invention, which will be described with reference to FIG.

The numerical controller 10 moves the table 6 on which the workpiece 5 is placed in the XY directions in order to control the position where the laser beam 2 is irradiated and the relative position between the workpiece 5 and the workpiece 5. The drive command value is output to the X-axis drive unit 8 and the Y-axis drive unit 9 that are caused to operate. Laser irradiation timing data generator 2
Reference numeral 3 denotes buffers 19 and 20 for temporarily storing the command values output from the numerical controller 10 for each axis, and movement path information based on the drive command values stored in the buffers 19 and 20. It has a data generation calculation unit 21 that generates the laser irradiation timing data with the pre-reading relative movement amount as a parameter, and a data buffer 22 that stores the laser irradiation timing data. The data generation / calculation unit 21 generates the laser irradiation timing data and then first-in first-out the command values stored in the buffers 19 and 20 via the D / A converters 11 and 12 to the X-axis drive unit. 8 and the Y-axis drive unit 9. The encoders 13 and 14 detect the amount of change in the relative position between the laser beam 2 irradiation position and the workpiece 5 based on the operation of the X-axis drive unit 8 and the Y-axis drive unit 9. The detected signal is fed back to the numerical controller 10 to subtract the drive command value. Here, the table 6 continues to move until the drive command value becomes zero. The counters 15 and 16 count the signals detected by the encoders 13 and 14. The laser irradiation output signal control unit 25 has a register 24 for taking in the laser irradiation timing data outputted from the data buffer 22, and the laser irradiation timing data taken in this register 24 and the counters 15 and 16 are counted. The count value is compared and a pulse signal is output to the laser oscillation unit 1 based on the comparison result. The laser oscillation unit 1 outputs a laser pulse according to this pulse signal.

Next, the operation of one embodiment of the laser processing apparatus of the present invention will be described with reference to the flow chart shown in FIG.

First, the numerical control unit 10 is set with a command value for instructing the drive units 8 and 9 for each axis to move the table 6 (S21).

The command values thus set are temporarily stored in the buffers 19 and 20 in the laser irradiation timing data generation unit 23 (S22), and the command values are stored in the data generation calculation unit 21 as laser irradiation timing data. It is referred to when it is created. The data generation calculation unit 21 continues to generate the laser irradiation timing data until the "predetermined condition" is satisfied (S23), and the laser irradiation timing data when the condition is satisfied is stored in the data buffer 22.
(S24).

Next, the command values stored in the buffers 19 and 20 are referred to for generating the laser irradiation timing data, and then the table 6 is transferred to the XY direction via the D / A converters 11 and 12. X-axis drive unit 8 and Y for moving in the direction
It is output to the axis drive unit 9, and the X-axis drive unit 8 and the Y-axis drive unit 9 are driven according to the command value, and the table 6
Moves (S25).

The moving amount of the table 6 is determined by the encoder 13,
It is detected by 14 (S26), and the movement amount is counted by the counters 15 and 16 (S28). Also,
The outputs from the encoders 13 and 14 are fed back to the numerical controller 10 to subtract the set command value (S27). When the command value output from the numerical control unit 10 becomes 0, the movement of the table 6 ends (S2).
13).

Next, the laser irradiation timing data stored in the data buffer 22 is loaded into the register 24 (S29).

The laser irradiation output signal controller 25 compares the laser irradiation timing data stored in the register 24 with the count values counted by the counters 15 and 16 (S210). This comparison is continued until the "predetermined condition" is satisfied. When this condition is satisfied, the laser irradiation output signal control unit 25 outputs the laser irradiation pulse signal to the laser oscillation unit 1 (S21).
Along with 1), the counter value is reset (S21).
2).

The laser oscillation unit 1 outputs a laser pulse according to the laser irradiation pulse signal.

Next, the procedure for generating the laser irradiation timing data will be described with reference to FIGS. 3, 5 and 6.

FIG. 3 is a flow chart showing the procedure for generating the laser irradiation timing data, and FIG. 5 is an explanatory view showing the relationship between the machining path and the command pulse.
FIG. 4 is an explanatory diagram showing a relationship between a processing path and a laser irradiation spot position.

First, each variable used to generate the laser irradiation timing data is initialized (S31).
That is, t = 0, Lt ² = 0, and Lr ² = 0. Here, t is the time, Lt is the length of the machining movement up to the time t, L
r is a variable for taking care not to accumulate the calculation error of the laser irradiation position.

Next, the value of each variable is calculated (S32).
Lt ² = L (t-Δt) ² + Pxt ² + Pyt ² + Lr
² is the calculation of the square value of the machining movement length Lt, and in this formula, L (t-Δt) ² is the machining movement length of the calculated value for the data one cycle before, and Pxt and Pyt are Command pulses Px and Y for the X-axis drive unit 8 respectively
The value of the command pulse Py for the axis drive unit 9 at time t is shown. Further, here, it is not necessary to calculate the square root for calculating the machining movement length. Also,
In SPx = Σ | Pxt | and SPy = Σ | Pyt |, the sum of the command pulses Px and Py for the X-axis and the Y-axis from the start of machining to time t is calculated.
Here, SPx and SPy respectively correspond to the area of the vertical line portion from the calculation start time to time t in FIG.

Next, the square value of the machining movement length Lt and FIG.
The square value of the laser irradiation interval Ld given in advance is compared (S33).

In the above comparison, when Lt ² ≧ Ld ² , laser irradiation timing data transfer and fraction Lr
And zero-clear the machining movement length Lt (S
34). Here, the calculated values of SPx and SPy are transferred as laser irradiation timing data to the register 24 in the laser irradiation output control unit via the data buffer. By indirectly transferring in this manner, the arithmetic processing of laser irradiation data generation and the arithmetic processing of the laser irradiation output control unit can be performed asynchronously. Also, Lr ² = Lt ²
-Calculate Ld ² . This is done in order to take care of the next calculation so that minute errors in calculation do not accumulate.

Next, the time counter is incremented in order to calculate the next command data (S35). That is, t = t + Δt.

As a result of the comparison in S33, Lt ² ≤Ld
^In the case of ² , the process directly goes to S35.

The command value output from the numerical control unit 10 is 0.
If it is determined that the arithmetic processing has ended, and if the arithmetic processing has not ended, the process returns to S32 (S36).

Next, the control procedure in the laser irradiation output signal control section 25 will be described with reference to the flow chart shown in FIG.

Laser irradiation timing data SPx and S calculated by the laser irradiation timing data generator
Lx for each Py from the data buffer to the register 24
And read as Ly (S41).

Next, the laser irradiation timing data Lx and Ly set in the register 24 and the counter 1 are set.
The count values X and Y of the encoder feedback pulse counted in 5 and 16 are compared with each other (S42).

In the above comparison, Lx ≦ X and Ly ≦ Y
Then, the laser irradiation pulse signal is sent to the laser oscillation unit 1
(S43).

In the above comparison, Lx ≦ X and Ly ≦ Y
If is not established, the comparison in S42 is repeated.

The laser oscillation unit 1 oscillates the laser one pulse each time the laser irradiation pulse signal is received.

[0046]

As described above, in the laser processing apparatus of the present invention, the relative movement amount between the laser light irradiation position and the workpiece is compared with the laser irradiation timing data stored in the register by complicated calculation. Since it can be executed without performing, it corresponds to the feedback of the relative movement amount of the laser light irradiation position and the workpiece output from the encoder at high speed,
The irradiation timing of the laser light can be controlled without causing a time delay. Thus, the laser processing apparatus of the present invention makes the laser light energy density per processing unit length constant regardless of the change in the relative processing speed, that is, the change in the relative speed between the laser light irradiation position and the workpiece. It is possible to improve the quality of laser processing.

Further, it is not necessary to improve the conventional numerical control section, and the effect of the present invention can be obtained only by adding the control means of the present invention as a unit.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 3 is a flowchart showing a procedure for generating laser irradiation timing data.

FIG. 4 is a flowchart showing a laser irradiation pulse output procedure.

FIG. 5 is an explanatory diagram showing a relationship between a machining path and a command pulse.

FIG. 6 is an explanatory diagram showing a relationship between a processing path and a laser irradiation spot position.

FIG. 7 is a configuration diagram showing a general laser processing apparatus.

FIG. 8 is a block diagram showing an example of a conventional laser processing apparatus.

[Explanation of symbols]

 1 Laser Oscillation Unit 2 Laser Light 3 Mirror 4 Lens 5 Workpiece 6 Table 7 Control Section 8 X-Axis Drive Section 9 Y-Axis Drive Section 10 Numerical Control Section 11, 12 D / A Converter 13, 14 Encoder 15, 16 Counter 17 Registers 18 Arithmetic Units 19 and 20 Buffers 21 Data Generation Arithmetic Units 22 Data Buffers 23 Laser Irradiation Timing Data Generators 24 Registers 25 Laser Irradiation Output Signal Control Units

Claims (4)

[Claims] 1. A laser oscillation unit for pulse-oscillating a laser, a numerical control means for outputting a command value for changing a relative position of the laser and a workpiece, and a first storage means for temporarily storing the command value. And, based on the command value stored in the first storage means, pre-read the change in the relative position between the laser and the workpiece, and laser irradiation timing data having the pre-read relative movement amount as a parameter. Data generating means for generating, read the command value stored in the first storage means on a first-in first-out basis, based on the command value, drive means for changing the relative position of the laser and the workpiece, A detection unit that detects the amount of change in the relative position between the laser and the workpiece, the amount of change in the relative position detected by the detection unit, and the data generation unit. And a timing control means for controlling a laser irradiation timing based on the laser irradiation timing data. 2. Before the laser irradiation timing data generated by said data generating means is outputted to said timing control means, said laser irradiation timing data is provided with second storage means for temporarily storing this laser irradiation timing data. The laser processing apparatus according to claim 1. 3. The data generating means calculates the sum of the square value of the laser machining movement path and the command value based on the command value output from the numerical control means, and the laser machining movement path 2 is calculated. It is characterized in that the power value Lt ² is compared with the square value Ld ² of the laser irradiation position interval, and the sum of the command values when Lt ² ≧ Ld ² as a result is output as laser irradiation timing data. The laser processing apparatus according to claim 1 or 2, wherein 4. The timing control means compares the laser irradiation timing data output from the data generating means with the change amount of the relative position detected by the detecting means, and the comparison result satisfies a predetermined condition. The laser processing apparatus according to claim 1, wherein a laser irradiation timing pulse signal is output to the laser oscillation unit every time.