JPH0659555B2 - Laser processing equipment - Google Patents

Description

The present invention relates to a laser processing apparatus.

[Conventional technology]

A laser processing method and an apparatus for performing processing while focusing a laser beam by a focusing lens and irradiating the object to be processed with the laser beam are known.

Laser processing is performed by changing the optical path of laser light oscillated from a laser oscillator directly or by a reflecting mirror, focusing it with a focusing lens, etc., and irradiating the processed portion of the workpiece with complicated processing. Since it is possible to process a shape in a short time, it is currently used in a wide variety of fields.

Thus, the machining feed between the workpiece and the laser beam applied to the workpiece is usually performed by moving one of the two by a numerical controller. In that case, the machining feed along the contour line of a desired shape is achieved by variously changing the feed amount in the X-axis direction and the feed amount in the Y-axis direction per unit time. The actual machining feed rate to be realized is represented by the vector sum of the X-axis direction feed rate and the Y-axis direction feed rate. Therefore, the machining feed rate slightly changes according to the change in the machining direction. Will be done.

[Problems to be solved by the invention]

Thus, if the machining feed rate changes as described above, assuming that the intensity of the laser beam is always constant during the machining period, the machining is performed insufficiently in the portion where the machining feed is fast,
On the other hand, excessive machining is performed in a portion where the machining feed is slow, so that uniform machining is not performed, and there arises a problem that a cutting line or a machined surface is uneven.

Of course, it is not impossible to adjust the X-axis feed rate and the Y-axis feed rate to draw a desired machining contour line at a constant machining feed rate, but then the program of the numerical controller becomes complicated. Therefore, there was a problem that the labor cost and other expenses for programming increased.

It has also been proposed to control the output of the laser oscillator so that the irradiation intensity of the laser beam on the workpiece is proportional to the processing feed rate.However, when the output of the laser oscillator is changed, amplification by stimulated emission is Since it is not necessarily proportional to the discharge voltage or current for pumping, it is not easy to finely and accurately control the output of the laser oscillator to a desired output, and a complicated device is required for that purpose.

The present invention has been made to solve the above problems, and an object of the present invention is to require a complicated device for changing and controlling the output of a laser oscillator by numerical control based on a simple program. Another object of the present invention is to provide a laser processing apparatus capable of performing uniform and highly accurate processing with a simple configuration.

[Means for solving problems]

Thus, in the laser processing apparatus for performing laser processing by relatively moving the workpiece and the laser beam irradiation point by the numerical control device, the above-mentioned object is a circle which is provided and rotated on the optical path of the laser beam. A plate-shaped chopper plate, in which a large number of transmission holes are provided on the circumference of each of a plurality of concentric circles centering on the rotation center axis, and the ratios of the lengths of the transmission hole portions to the lengths of the circumferences are different from each other. A chopper plate formed as described above, a laser intensity conversion device that selectively changes the irradiation position of the output laser beam of the laser oscillator with respect to the chopper plate to one of the plurality of concentric circles, and the output signal of the numerical control device. Based on the calculation result of the arithmetic device, the intensity of the laser beam irradiated to the workpiece is increased based on the calculation result of the arithmetic device. It is achieved by the laser machining apparatus characterized by being configured to control the laser intensity converter to be substantially proportional to the moving speed.

[Work]

With the above configuration, the laser intensity is increased in the portion where the machining feed is fast, and conversely, the laser intensity is decreased in the portion where the machining feed is slow, so that uniform machining is performed regardless of the variation of the machining feed speed. This eliminates the need for a complicated program to keep the machining feed rate constant.
Good processing can be performed with a simpler configuration than by changing and controlling the output of the laser oscillator.

〔Example〕

Hereinafter, the details of the present invention will be specifically described with reference to an embodiment of the laser processing apparatus according to the present invention shown in the drawings.

FIG. 1 is an explanatory view showing an embodiment of the laser processing apparatus according to the present invention, and FIG. 2 is an explanatory view of the chopper plate thereof.

In both figures, 1 is a laser oscillator, 2 is a power source for operating the laser oscillator, and other laser oscillation drive circuits, and 3 is a side surface of the side facing the laser oscillator 1 formed of a reflecting mirror. A disk-shaped chopper plate having a plurality of laser beam transmission holes formed therein, 4 a motor for rotating the chopper plate 3, 5 a motor mount, and 6 a motor mount 5
1 is moved up and down along the guide rail 7 in the vertical direction in FIG. 1 to move the chopper plate 3 in the radial direction so that the chopper plate 3 can be moved toward and away from the axis of the laser oscillator 1, and 8 is the lifting motor 6 described above. Drive circuit, 9 is a reflecting mirror for changing the optical path of the laser beam, 10 is a focusing lens for converging the laser beam reflected by the reflecting mirror 9 onto the workpiece 11, 12 is a cross slide table, and 13 is the above cross slide. X-axis direction moving table of table, 14 Y-axis direction moving table,
Reference numeral 15 is a base, 16 is a motor for driving the X-axis direction moving table 13 on the Y-axis direction moving table 14 along the X-axis direction,
Reference numeral 17 is a motor for driving the Y-axis direction moving table 14 on the base 15 along the Y-axis direction, 18 is a numerical controller, and 19 is a vector operation using an output signal of the numerical controller 18. A machining feed rate calculation device for calculating the machining feed rate of the workpiece with respect to the laser beam, 20 compares the machining feed rate calculated by the machining feed rate calculation device 19 with a plurality of values set in advance in stages. Is a comparison circuit that sends a signal to the drive circuit 8 of the lifting motor 6 to operate the motor 6 based on the comparison result. The laser intensity conversion device includes the motor 6, the guide rail 7, the motor drive circuit 8, and the comparison circuit 20. Is configured.

In order to prevent the drawing from becoming complicated, a cooling device of the laser oscillator 1, a desired gas supply to the processing portion and other atmosphere control means, a means for removing steam or gas generated during processing, or a portion other than the processing portion. The shielding device and the like for preventing the laser light leakage are omitted in the figure.

Thus, as the laser oscillator 1, any one of a gas laser, a liquid laser, a solid laser, and a semiconductor laser can be used.

The chopper plate 3 arranged so as to face the laser oscillator 1 in the optical path of the laser beam emitted from the laser oscillator 1 is, for example, concentric with the disk-shaped chopper plate 3 as shown in FIG. A plurality of laser beam transmission holes 3a, 3a, 3b, 3b, 3c, 3c, 3 are provided on the circumferences A, B, C, D of the plurality of concentric circles having different radii.
d, 3d, etc. are formed such that the ratio of the total length of the through holes to the length of the circumference is different. The chopper plate 3 is rotated by the motor 4, and the motor mounting base 5 is moved along the guide rail 7 by the elevating motor 6 to move the laser oscillator 1
It is configured so as to be close to or apart from the center of rotation along an axis that is in the radial direction with respect to the axis.

Therefore, the laser beam emitted from the laser oscillator 1 is transmitted through the rotating holes 3a, 3a, 3b, 3b, 3 of the chopper plate 3.
After being turned on / off by passing through any one group of transmission holes on the same radius of c, 3c or 3d, 3d, the optical path is changed by the reflecting mirror 9 and focused by the focusing lens 10 to be processed. Collected at processing points on body 11.

In this case, when the position of the chopper plate 3 is set so that the laser beam is allowed to pass through the transmission holes 3a, 3a on the circumference A, the number of the transmission holes 3a, 3a on the circumference A is set to the other circumferences. B, C, D
Since the number of the upper transmission holes is smaller, the intensity of the laser beam passing through the chopper plate is the lowest, and the intensity of the laser beam is set by passing through the transmission holes on the circumference B or C. Is gradually increased stepwise, and the circumference D
It will be easily understood that the maximum intensity is obtained when it is set to pass through the upper transmission holes 3d, 3d. In addition, the transmission holes 3d, 3d on the circumference D are not round holes, but are formed as holes having a predetermined length in the circumferential direction, and the ratio of the total length of the transmission holes to the length of the circumference is Although it is attempted to increase the height, the transmission holes on the circumferences A, B, and C can also be holes of an appropriate shape instead of round holes.

On the other hand, the workpiece 11 is mounted on the X-axis direction moving table 13 of the turntable 12, and the motors 16 and 17 are driven by a numerical controller 18 in accordance with a predetermined program so that the workpiece 2 can be moved in the same plane. The laser beam is moved dimensionally, and thereby, the processing feed between the workpiece and the laser beam is given, and the laser processing along the desired processing contour line is performed.

Thus, when processing is performed by the laser processing apparatus according to the present invention, the output signal of the numerical controller 18 is the motor 16
And 17 for the desired machining feed, and the above signal is also sent to the machining feed speed calculation device 19 for calculating the actual machining feed speed between the laser beam and the workpiece. .

That is, since the output signal from the numerical controller 18 is an information signal relating to the X-axis direction feed amount and the Y-axis direction feed amount per unit time (that is, the X-axis direction feed rate and the Y-axis direction feed rate), both The actual machining feed rate can be easily calculated by obtaining the vector sum.

Thus, the calculation result obtained by the calculation device 19 is the comparison circuit.
It is sent to 20 and compared with some preset values for the machining feed rate in the circuit. At this time, for example, the values α, β, γ, δ are set in the comparison circuit 20 sequentially from the one having a low machining feed speed to the one having a high machining feed speed, and the optimum laser intensity for machining when the value of α is It is the laser intensity when the beam is passed through the transmission holes 3a, 3a on the circumference A of the chopper plate 3, and in the following description, when it is β, the circumference B
It is assumed that the laser intensity when passing through the upper transmission hole, the transmission hole on the circumference C when γ, and the transmission hole on the circumference D when δ are set to be optimum. At that time, the machining feed rate is initially low and the laser beam is allowed to pass through the transmission holes 3a, 3a on the circumference A of the chopper plate 3 to start machining, and then the machining feed rate. Is, for example, increased to β or more and is calculated by the arithmetic unit 19 and the value as the calculation result is provided to the comparison circuit 20, the comparison circuit 20 determines that the machining feed rate is the set value β in the comparison circuit. Make a determination that you have exceeded,
A signal is sent to the drive circuit 8 of the motor 6 to rotate the motor 6 to move the chopper plate 3 upward in FIG. 1, so that the laser beam passes through the transmission holes 3b, 3b on the circumference B of the chopper plate. Control is performed to increase the intensity of the laser beam that passes through the chopper plate and is irradiated onto the workpiece 11. The same applies to other cases. For example, when the machining feed rate calculated by the arithmetic unit 19 is γ or higher and lower than δ, the laser beam passes through the transmission holes 3c, 3c on the circumference C of the chopper plate. When the machining feed rate is δ or more, the chopper plate is moved so that the laser beam passes through the transmission holes 3d, 3d on the circumference D. On the contrary, when the machining feed rate is lowered from, for example, δ or more to δ or less and γ or more, the chopper plate 3 moves from the state where the laser beam passes through the transmission hole on the circumference D to the circumference C. It is switched to a state of passing through the upper transmission hole.

In order to know the current position of the chopper plate, it is possible to provide a sensor such as an encoder between the motor mount 5 and the guide rail 7. An up / down counter for measuring the rotation amount of the motor 6 may be incorporated in the circuit 8 so that the position of the chopper plate can be known from the display value of the counter, and the data from this counter is input to the comparison circuit 20. It is possible to determine whether the chopper plate should be raised or lowered from the current position when the machining feed speed changes, and based on this, a signal is sent from the comparison circuit 20 to the motor drive circuit 8. The chopper plate 3 can be raised or lowered.

As described above, the chopper-type laser intensity converter for selectively passing the output beam of the laser oscillator 1 through any one of the plurality of transmission hole groups concentrically provided in the chopper plate 3 is used according to the processing feed speed. As a result, as shown by the dotted line in FIG. 1, compared to the case where the signal from the comparison circuit 20 controls the laser oscillation drive circuit 2 to change and control the output of the laser oscillator 1, The irradiation intensity of the laser beam can be controlled finely and accurately with a simple structure.

Further, in the drawings, the arithmetic unit 19 for calculating the machining feed speed is shown separately from the numerical control unit 18, but the numerical control unit itself is configured to perform this calculation. In addition, it is possible to simultaneously perform the function of the machining feed rate calculation device.

〔The invention's effect〕

Since the present invention is configured as described above, according to the present invention, the laser intensity is increased in the portion where the machining feed is fast, and conversely, the laser intensity is reduced in the portion where the machining feed is slow, so that the machining point is Is a method in which substantially uniform laser energy is applied regardless of fluctuations in the machining feed rate to perform uniform machining. Therefore, a complicated program for keeping the machining feed rate constant is unnecessary, and a simple program However, uniform and high-precision processing is possible, and by using the above-mentioned chopper type laser intensity conversion device, the laser energy applied to the workpiece can be controlled easily and precisely with a simple configuration. High-precision processing can be performed.

The present invention is not limited to the above embodiments. That is, for example, the shape, size, arrangement, etc. of the through holes formed in the chopper plate 3 can be arbitrarily set according to the value of the laser intensity to be changed, and in the above embodiment, the motor mount 5 is used. Although the motor 6 is moved up and down by the motor 6, it may be moved vertically by hydraulic pressure or the like. In addition, the position where the focusing lens 10 is provided, the position where the chopper plate is attached, the method of rotating the same, the method of controlling the same, etc. can be freely designed and changed within the scope of the object of the present invention. Furthermore, when performing the machining feed, the laser irradiation device including a laser oscillator and a focusing lens may be moved instead of moving the workpiece.

Further, the present invention is also applicable to the case of machining using a numerical control device configured so that the machining feed is performed at a set constant feed speed regardless of the change in the vector direction of the machining feed direction. Applicable, for example, in the case of a machining mode in which the cutting thickness, machining depth, etc. vary depending on the partial thickness of the workpiece and the purpose of machining, etc. It seems that the target processing can be performed by changing and controlling the laser intensity by the program instead of the one that is changed and set.

Therefore, the present invention covers all modified embodiments that can be easily conceived by those skilled in the art from the above description.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the laser processing apparatus according to the present invention, and FIG. 2 is an explanatory view of the chopper plate thereof. 1 …… Laser oscillator 2 …… Laser oscillation drive circuit 3 …… Chopper plate 3a, 3a to 3d, 3d …… Laser beam transmission hole 4 …… Motor 5 …… Motor mount 6 …… Elevating motor 7 …… Guide rail 8 …… Motor drive circuit 9 …… Reflecting mirror 10 …… Converging lens 11 …… Workpiece 12 …… Cross slide table 13 …… X axis direction moving table 14 …… Y axis direction moving table 15 …… Base Platform 16, 17 …… Motor 18 …… Numerical controller 19 …… Processing feed rate calculator 20 …… Comparison circuit

Claims (1)

[Claims] 1. A disk-shaped chopper provided on an optical path of a laser beam and rotated in a laser processing apparatus for performing laser processing by relatively moving a workpiece and a laser beam irradiation point by a numerical controller. A plate, in which a plurality of transmission holes are formed on the circumference of each of a plurality of concentric circles centering on the center axis of rotation so that the ratio of the length of the transmission hole portion to the length of the circumference is different. Chopper board,
A laser intensity conversion device for selectively changing the irradiation position of the output laser beam of the laser oscillator with respect to the chopper plate to one of the plurality of concentric circles, and the workpiece and the laser beam irradiation point based on the output signal of the numerical control device. And an arithmetic unit for determining a relative movement speed between the laser intensity conversion apparatus and the laser intensity converter so that the intensity of the laser beam applied to the workpiece based on the calculation result of the arithmetic unit is substantially proportional to the movement speed. A laser processing apparatus having the above structure.