JP2012076106A - Laser beam machining apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus capable of securing the safety relating to wrong irradiation of a laser beam.SOLUTION: A branching mirror 70 is arranged on the beam path of the laser beam for branching part of the laser beam and extracting it. A photoelectric converter 71 is provided for detecting a laser beam extracted from the branching mirror 70. A controller 60 judges that an abnormal condition is generated from the detected result of the laser beam by the photoelectric converter 71 and from the state of the outputted signal of a print start button, when a laser beam is detected by the photoelectric converter 71 while a machining start order is not given. The controller 60 stops power supply to a laser beam oscillator 20 so that the laser beam is not emitted outward, when the abnormal condition is detected.

Description

  The present invention relates to a laser processing apparatus.

  2. Description of the Related Art Conventionally, for example, there is a laser oscillator that includes a laser oscillator and generates laser light based on excitation of a laser medium of the laser oscillator by an excitation signal that is an external pulse signal (see, for example, Patent Document 1).

JP 2000-22250 A

However, when the mode is not shifted to the laser beam irradiation mode and the laser beam is irradiated due to a problem on the system, the workpiece is irradiated with an unnecessary laser beam.
The objective of this invention is providing the laser processing apparatus which can ensure the safety | security regarding the misirradiation of a laser.

  According to the first aspect of the present invention, a laser oscillator that outputs a laser beam for irradiating the workpiece, and a machining start signal that outputs a machining start signal for starting the machining by the laser beam irradiation on the workpiece. A signal output means; a branch means provided in the optical path of the laser light; for branching out and taking out part of the laser light; a photoelectric converter for detecting the laser light taken out by the branch means; From the detection result of the laser beam by the photoelectric converter and the output state of the processing start signal by the processing start signal output means, it is abnormal if the laser beam is detected by the photoelectric converter when no processing start instruction is issued. The gist includes an abnormality detecting means for determining and a prohibiting means for preventing laser light from being emitted to the outside when an abnormality is detected by the abnormality detecting means.

  According to the first aspect of the present invention, the machining start signal output means outputs a machining start signal for starting machining by irradiating the workpiece with the laser beam. In the laser oscillator, laser light for irradiating the object to be processed is output.

  Here, a part of the laser light is branched and extracted by the branching means provided in the optical path of the laser light, and the laser light extracted by the branching means is detected by the photoelectric converter. Then, the laser beam is detected by the photoelectric converter when the machining start instruction is not issued from the detection result of the laser beam by the photoelectric converter and the output state of the machining start signal by the machining start signal output unit by the abnormality detection unit. Then, it is determined to be abnormal. When an abnormality is detected by the abnormality detection unit, the prohibition unit prohibits laser light from being emitted to the outside. As a result, safety related to erroneous laser irradiation can be ensured.

  According to a second aspect of the present invention, in the laser processing apparatus according to the first aspect, the prohibiting means prevents the laser light from being emitted to the outside by stopping the power supply to the laser oscillator. To do.

According to the second aspect of the present invention, in the prohibiting means, the power supply to the laser oscillator is stopped, so that the laser beam is not emitted to the outside.
According to a third aspect of the present invention, in the laser processing apparatus according to the first aspect, the prohibiting means prevents the laser light from being emitted to the outside by closing a shutter disposed in the optical path of the laser light. And

According to the third aspect of the present invention, in the prohibiting means, the shutter disposed in the optical path of the laser beam is closed, so that the laser beam is not emitted to the outside.
According to a fourth aspect of the present invention, in the laser processing apparatus according to the third aspect, in the shutter, the light shielding member is urged to the closed side by the mechanical urging means in the non-power state, and the control signal is input. The gist is that it is configured to open by.

  According to the fourth aspect of the present invention, since the shutter has a configuration in which the light shielding member is urged to the closed side by the mechanical urging means in the non-powered state and is opened by the input of the control signal, the error of the laser is caused. It is preferable for safety related to irradiation.

  The invention according to claim 5 is the laser processing apparatus according to any one of claims 1 to 4, further comprising alarm means for warning when the abnormality detecting means determines that the abnormality is detected. The gist.

  According to the fifth aspect of the present invention, an alarm is issued when the alarm means determines that an abnormality is detected by the abnormality detection means. Therefore, it is preferable for ensuring safety related to erroneous laser irradiation.

  According to a sixth aspect of the present invention, in the laser processing apparatus according to any one of the first to fifth aspects, an operational amplifier that amplifies and outputs an electric signal at a level corresponding to the output of laser light from the photoelectric converter And an A / D converter for A / D converting the output signal of the operational amplifier, and an output value of the laser light after A / D conversion by the A / D converter, and A / D conversion from time to time Difference processing means for calculating a difference between the output value of the detector and the output value of the A / D converter before laser irradiation, which has been obtained in advance, as a monitor value of the laser beam, and the abnormality detection means comprises an abnormality determination In this case, the gist is to determine that the laser beam is detected if the monitor value by the difference processing means is equal to or greater than a threshold value.

  According to the invention described in claim 6, the operational signal is amplified by the operational amplifier at a level corresponding to the output of the laser beam from the photoelectric converter, and the output signal of the operational amplifier is A / D converted by the A / D converter. . In the difference processing means, the difference between the output value of the A / D converter from time to time and the output value of the A / D converter before laser irradiation obtained in advance is calculated as the monitor value of the laser beam. Then, it is determined by the abnormality detection means that the laser beam is detected when the monitor value by the difference processing means is equal to or greater than the threshold value at the time of abnormality determination.

As a result, the influence of the dark current of the photoelectric converter and the temperature of the operational amplifier can be reduced.
As described in claim 7, in the laser processing apparatus according to claim 6, the abnormality detection unit continues the state in which the monitor value by the difference processing unit is equal to or greater than a threshold value for a predetermined time or more at the time of abnormality determination. Then, the gist is to determine that the laser beam has been detected.

  According to the seventh aspect of the present invention, in the abnormality detection means, it is determined that the laser beam has been detected when the state where the monitor value by the difference processing means is greater than or equal to the threshold value continues for a predetermined time or more in the abnormality determination. Therefore, the laser beam can be reliably detected.

  According to the present invention, it is possible to ensure safety related to erroneous laser irradiation.

A perspective view showing a schematic structure of a laser marking device in an embodiment. The block diagram which shows schematic structure of a laser marking apparatus. The block diagram which shows schematic structure of a laser oscillator. The front view of a console. The wave form diagram for demonstrating the effect | action of a laser marking apparatus. The wave form diagram for demonstrating the effect | action of a laser marking apparatus. The wave form diagram for demonstrating the effect | action of a laser marking apparatus.

Hereinafter, an embodiment in which the present invention is embodied in a laser marking device will be described with reference to the drawings.
FIG. 1 is a perspective view of the laser marking device 1, and FIG. 2 is a block diagram of the laser marking device.

  As shown in FIG. 1, a laser marking device 1 as a laser processing device includes a controller 2 that emits laser light L. A head 4 is connected to the controller 2 via a fiber cable 3. A head 4 is connected to the controller 2 via an electric cable 5, and a console 7 is connected to the controller 2 via an electric cable 6. The laser marking device 1 is configured to mark a desired character, figure, symbol, or the like (hereinafter referred to as a character) on the marking surface Wa of the workpiece W mounted on the mounting table 8.

A window portion 9 from which the laser beam L is emitted is formed on the lower surface of the head 4. The head 4 is installed such that the window portion 9 faces the marking surface Wa of the workpiece W.
As shown in FIG. 2, the controller 2 includes a laser oscillator 20, and laser light L is emitted from the laser oscillator 20.

In the present embodiment, the fiber laser oscillator shown in FIG.
As shown in FIG. 3, the laser oscillator 20 includes an optical fiber 21, a laser diode LD1, a laser diode LD2, a laser diode LD3, and a driver 22. The driver 22 is supplied with power from a power source. The laser diode LD1 serves as a signal laser light source, and the laser diodes LD2 and LD3 serve as excitation laser light sources. The optical fiber 21 contains yttrium (Yb), which is a rare earth element, and the rare earth-doped optical fiber 21 is wound many times to ensure an optical path having a required length. The rare earth doped optical fiber 21 is provided with an optical isolator 24 that allows laser light to pass through only one side. An optical fiber 25 a is coupled to one end side of the rare earth doped optical fiber 21, and an optical fiber 25 b is coupled to the other end side of the rare earth doped optical fiber 21. Laser light from the laser diode LD1 is incident on one end of the rare earth-doped optical fiber 21 through the optical fiber 26a, and laser light from the laser diode LD2 through the optical fiber 25a is joined. Laser light from the laser diode LD3 that has passed through the optical fiber 25b is incident on the other end of the rare earth-doped optical fiber 21, and laser light is output from the other end of the rare-earth doped optical fiber 21 through the optical fiber 26b. .

  The driver 22 includes switching elements (power transistors) Q1, Q2, Q3 and a power switch SW1. The switching element Q1 is connected to the laser diode LD1, the switching element Q2 is connected to the laser diode LD2, and the switching element Q3 is connected to the laser diode LD3. The switching elements Q1, Q2, and Q3 are connected to a power source through a power switch SW1. Then, with the power switch SW1 turned on (closed), the switching elements Q1, Q2 and Q3 are turned on to emit light from the corresponding laser diodes LD1, LD2 and LD3, and the light from the laser diodes LD2 and LD3 Laser light is output by being excited in the optical fiber 21.

Thus, the laser oscillator 20 can output the laser beam for irradiating the workpiece W.
The laser light L emitted from the laser oscillator 20 is sent to the fiber cable 3 in FIG. 1, and the laser light is sent to the head 4 through the fiber cable 3. As shown in FIG. 1, one end of the fiber cable 3 is connected to the beam expander housing 10 in the head 4. A beam expander 30 (see FIG. 2) is accommodated in the beam expander accommodating portion 10, and laser light from the fiber cable 3 is sent to the beam expander 30.

  As shown in FIG. 2, first and second galvanometer mirrors 40 </ b> X and 40 </ b> Y and a condensing lens 50 are arranged in the optical path of the laser beam L in the head 4 in order from the laser oscillator 20 side. The laser light L from the beam expander 30 is incident on the first and second galvanometer mirrors 40X and 40Y.

  The first and second galvano mirrors 40X and 40Y are connected to the corresponding first and second galvano motors 41X and 41Y so as to be rotatable. The first and second galvano motors 41X and 41Y rotate the first and second galvanometer mirrors 40X and 40Y, respectively, about axes that are substantially orthogonal to each other. The first and second galvanometer mirrors 40X and 40Y reflect the laser light L from the beam expander 30 and change its emission direction. Specifically, the first galvanometer mirror 40X rotates and scans the laser beam L irradiated toward the workpiece W in one direction (X direction, see FIG. 1) of the marking surface Wa. It has become. Further, the second galvanometer mirror 40Y rotates and scans the laser beam L irradiated toward the workpiece W in a direction perpendicular to the X direction of the marking surface Wa (Y direction, see FIG. 1). It is supposed to let you. Therefore, the laser light L irradiated toward the workpiece W is scanned in the X direction and the Y direction with respect to the marking surface Wa of the workpiece W by the first and second galvanometer mirrors 40X and 40Y. It has become.

  The console 7 has a setting function and a display function. FIG. 4 is a front view of the console 7. As shown in FIG. 4, the console 7 has a display unit 80 for displaying machining characters, a display unit 81 for the origin position on the X axis, a display unit 82 for the origin position on the Y axis, and an origin position setting. Buttons 83a, 83b, 83c, 83d and a print start button 84 are provided. The origin position on the Y axis can be set using the origin position setting buttons 83a and 83b. Further, the origin position on the X axis can be set using the origin position setting buttons 83c and 83d. The set origin position on the Y axis is displayed on the display unit 82. The set origin position on the X axis is displayed on the display unit 81. Further, the set origin on the X and Y axes is displayed on the two-dimensional coordinates on the display unit 80. Printing is started by pressing the print start button 84.

  That is, the print start button 84 as a processing start signal output unit outputs a processing start signal for starting processing by the irradiation of the laser light L with respect to the processing target W. That is, in this embodiment, the processing is marking processing, and the processing start signal is a marking start signal.

  In FIG. 2, the controller 2 includes a control device 60 that comprehensively controls the laser marking device 1, and a memory 61 that includes a ROM or the like connected to the control device 60. The memory 61 stores marking information such as characters to be printed. This marking information includes information such as the coordinate values of the start point and end point of each line segment constituting the character and the like, the thickness of the line segment formed by the irradiation with the laser beam L, and the like.

  The control device 60 is connected to the console 7, and the control device 60 inputs an operation signal (marking start signal) of the print start button 84 in the console 7, an operation signal of the origin position setting buttons 83 a, 83 b, 83 c, and 83 d.

  The control device 60 is connected to the laser oscillator 20 and the first and second galvano motors 41X and 41Y, respectively. The control device 60 can control the switching elements Q1, Q2, Q3 and the power switch SW1 of the driver 22 (see FIG. 3) of the laser oscillator 20. Then, the control device 60 outputs a driving signal, that is, a signal for turning on the switching elements Q1, Q2, and Q3 in a state where the power switch SW1 is turned on to emit the laser light L, and the marking information stored in the memory 61 By driving and controlling the first and second galvano motors 41X and 41Y based on the above, the laser beam L is scanned two-dimensionally to mark predetermined characters on the marking surface Wa of the workpiece W. Yes.

  Further, as shown in FIG. 2, a branching mirror 70 as a branching unit is provided between the beam expander 30 and the first and second galvanometer mirrors 40X and 40Y on the optical path of the laser light at the head 4. It has been. The branching mirror 70 is a partial reflection mirror, and a part (for example, 1 to 2%) of the laser light is branched and extracted by the branching mirror 70. The laser light extracted by the branching mirror 70 is sent to a photoelectric converter (for example, a photodiode) 71. Using this photoelectric converter 71, the extracted laser beam can be detected.

  A photoelectric converter 71, an operational amplifier 72 as an amplifier, and an A / D converter 73 are connected in series, and a control device 60 is connected to the A / D converter 73. The operational amplifier 72 amplifies and outputs an electric signal having a level corresponding to the output of the laser beam from the photoelectric converter 71. An A / D converter 73 following the operational amplifier 72 performs A / D conversion on the output signal of the operational amplifier 72. The control device 60 receives an output value of the laser light after A / D conversion by the A / D converter 73 and makes an abnormality determination based on the detection result of the laser light by the photoelectric converter 71. .

Next, the operation of the laser marking device 1 configured as described above will be described.
FIG. 5 is a waveform diagram during normal operation. When the print start button 84 of the console 7 is pressed at the timing t 1, a trigger signal (SG 1) accompanying the operation of the print start button 84 is sent to the control device 60.

  Then, the control device 60 generates coordinate data (marking data) on the workpiece W from the information to be processed (characters, symbols, graphics, its size, thickness, printing speed, laser power, etc.). To do.

Then, the control device 60 sends a drive signal SG2 to the driver 22 of the laser oscillator 20 at the timing t2 in FIG.
In the period from t1 to t2 in FIG. 5 (before laser irradiation), the control device 60 stores the output value (watt value W1) of the A / D converter 73 before laser irradiation. That is, the output of the photoelectric converter 71 before the laser irradiation is amplified by the operational amplifier 72, A / D converted by the A / D converter 73 and taken into the control device 60, and the A / D converter before the laser irradiation. 73 as an output value (watt value W1).

  When the drive signal SG2 is sent to the driver 22 of the laser oscillator 20 at the timing t2 in FIG. 5, the switching elements Q1, Q2, Q3 are turned on with the power switch SW1 turned on in the driver 22 of the laser oscillator 20, and the laser beam is emitted. Is output.

  A part of the laser light output from the laser oscillator 20 is branched and extracted by the branching mirror 70, converted into an electric signal corresponding to the output (strength) of the laser light by the photoelectric converter 71, and the operational amplifier 72. In the A / D converter 73, the output of the operational amplifier 72 is A / D converted and output as a digital value.

  The control device 60 inputs an output value (digital value) of the laser beam from the A / D converter 73. The control device 60 calculates the difference between the output value (watt value W2) of the A / D converter 73 from time to time and the output value (watt value W1) of the A / D converter 73 before laser irradiation obtained in advance. Find (subtract). This W1-W2 is a true value, that is, a monitor value of the laser beam.

The output (power value) of the laser beam may be displayed on the console 7 based on the monitor value.
The control device 60 determines that the laser beam is detected when the monitor value is equal to or greater than the threshold value, and determines that the laser beam is not detected when the monitor value is less than the threshold value. And the control apparatus 60 determines the presence or absence of abnormality from the detection result of a laser beam, and the output state of a process start signal as follows.

  In the case of FIG. 5, the control device 60 detects the output of the laser beam after inputting the trigger signal (SG1) accompanying the pressing of the print start button 84, and therefore determines “normal”. That is, the control device 60 is normal when the laser light is detected by the photoelectric converter 71 when a processing start instruction is issued from the detection result of the laser light by the photoelectric converter 71 and the output state of the processing start signal. Is determined.

  In FIG. 6, in the driver 22 of the laser oscillator 20, the switching elements Q1, Q2, and Q3 are short-circuited for some reason. As a result, the trigger signal (SG1) associated with the pressing of the print start button 84 is not input, and the laser signal from the laser oscillator 20 is output from the laser oscillator 20 at the timing t10 in a state where the drive signal SG2 is not output to the driver 22 of the laser oscillator 20. Light has been output.

  Since the control device 60 detects the output of the laser beam without the input of the trigger signal (SG1) accompanying the pressing of the print start button 84, it is determined as “abnormal”. That is, the control device 60 is abnormal when the laser beam is detected by the photoelectric converter 71 when the processing start instruction is not issued from the output state of the detection result of the laser beam by the photoelectric converter 71 and the processing start signal. Is determined.

If the controller 60 determines “abnormal”, it immediately turns off (opens) the power switch SW <b> 1 in FIG. 3 and stops supplying power to the laser oscillator 20.
In this way, when an unexpected laser irradiation is performed when the laser irradiation mode is not shifted, it is immediately detected and an emergency stop is performed.

According to the above embodiment, the following effects can be obtained.
(1) As shown in FIG. 6, when a laser is irradiated even when a trigger signal and a drive signal to the laser oscillator 20 are not output, that is, an unexpected laser beam is irradiated even when the printing mode is not set. In such a case, the control device 60 monitors using the branch mirror 70, the photoelectric converter 71, the operational amplifier 72, and the A / D converter 73, and immediately stops the power supply to the laser oscillator 20.

  That is, in the control device 60 as the abnormality detection means, when a processing start instruction is not issued from the output state of the laser light detection result by the photoelectric converter 71 and the print start signal (processing start signal) by the print start button 84. When the laser beam is detected by the photoelectric converter 71, it is determined to be abnormal. The control device 60 as the prohibiting means prevents the laser light from being emitted to the outside when an abnormality is detected. Therefore, it is possible to ensure safety related to erroneous laser irradiation.

  (2) The control device 60 as the prohibiting means stops the laser beam from being emitted to the outside by stopping the power supply to the laser oscillator 20. Therefore, it is possible to ensure the safety related to erroneous laser irradiation more reliably.

  (3) The operational amplifier 72 amplifies and outputs an electric signal at a level corresponding to the output of the laser light from the photoelectric converter 71, and the A / D converter 73 performs A / D conversion on the output signal of the operational amplifier 72. The control device 60 as the difference processing means inputs the output value of the laser light after A / D conversion by the A / D converter 73, and obtains the output value of the A / D converter 73 at that time in advance. The difference between the output values of the A / D converter 73 before the laser irradiation is calculated as a monitor value of the laser beam, and the control device 60 as the abnormality detection means determines that the monitor value is equal to or greater than a threshold value when determining abnormality. It is determined that laser light has been detected. As a result, it is possible to monitor the output of the laser light accurately without being affected by the dark current in the photoelectric converter (photodiode) 71. Further, the output (intensity) of the laser beam can be accurately monitored by making it less susceptible to the temperature of the operational amplifier 72 (offset the offset).

The embodiment is not limited to the above, and may be embodied as follows, for example.
Instead of FIG. 6, as shown in FIG. 7, the drive signal SG <b> 2 to the laser oscillator 20 is output at the timing t <b> 20 before the trigger signal (SG <b> 1) is input at t <b> 21. Even when an unexpected laser beam is radiated in spite of not being in such a printing mode, it may be detected by the control device 60 and the power supply to the laser oscillator 20 may be stopped immediately.

  In (3) described above, the control device 60 serving as the abnormality detection means may determine that the laser beam has been detected when the state where the monitor value is equal to or greater than the threshold value continues for a predetermined time or more when determining the abnormality. . In this way, the laser beam can be reliably detected.

  The control device 60 as the prohibiting unit may be configured so that the laser light is not emitted to the outside by closing a shutter disposed in the optical path of the laser light. Here, the shutter has a configuration in which a light shielding member (for example, a rotating light shielding plate) is biased to a closed side by a mechanical biasing unit (for example, a return spring) in a non-powered state and is opened by an input of a control signal. Good. In this case, if the power supply to the shutter is stopped in conjunction with stopping the power supply of the laser oscillator, the shutter is in a non-powered state and the light-shielding member is biased to the closed side by the mechanical biasing means. Therefore, it is preferable in terms of safety regarding erroneous laser irradiation.

An alarm device may be further provided as an alarm unit that issues an alarm when the controller 60 as an abnormality detection unit determines that an abnormality has occurred.
Although embodied in a laser marking device provided with a fiber laser oscillator, the present invention is not limited to this and may be embodied in a laser marking device equipped with another oscillator. That is, as long as it is a gas gas laser, a carbon dioxide laser, an argon gas laser, a nitrogen gas laser, or the like may be used, and a solid laser is also applicable.

  Although embodied in a laser marking device, the present invention is not limited to this, and may be embodied in other laser processing devices such as a laser welding machine, a laser drilling machine, and a laser cutting machine.

  DESCRIPTION OF SYMBOLS 1 ... Laser marking apparatus, 7 ... Console, 20 ... Laser oscillator, 60 ... Control apparatus, 70 ... Branching mirror, 71 ... Photoelectric converter, 72 ... Operational amplifier, 73 ... A / D converter, 84 ... Print start button, L: Laser light, W: Object to be processed.

Claims (7)

A laser oscillator that outputs a laser beam for irradiating a workpiece;
A processing start signal output means for outputting a processing start signal for starting processing by irradiation of the laser beam with respect to the processing object;
A branching means provided in the optical path of the laser beam, for branching out and extracting a part of the laser beam;
A photoelectric converter for detecting the laser light extracted by the branching means;
From the detection result of the laser beam by the photoelectric converter and the output state of the machining start signal by the machining start signal output means, it is abnormal if the photoelectric converter detects the laser beam when no machining start instruction is issued. An abnormality detection means for determining
Prohibiting means for preventing laser light from being emitted to the outside when an abnormality is detected by the abnormality detecting means;
A laser processing apparatus comprising:   2. The laser processing apparatus according to claim 1, wherein the prohibiting unit prevents laser light from being emitted to the outside by stopping power supply to the laser oscillator. 3.   The laser processing apparatus according to claim 1, wherein the prohibiting unit prevents the laser light from being emitted to the outside by closing a shutter disposed in an optical path of the laser light.   4. The laser processing apparatus according to claim 3, wherein the shutter has a configuration in which the light shielding member is urged to the closed side by a mechanical urging unit in a non-powered state and is opened by an input of a control signal.   The laser processing apparatus according to claim 1, further comprising a warning unit that gives a warning when it is determined that the abnormality is detected by the abnormality detection unit. An operational amplifier that amplifies and outputs an electric signal of a level corresponding to the output of the laser beam by the photoelectric converter;
An A / D converter for A / D converting the output signal of the operational amplifier;
The output value of the laser beam after A / D conversion by the A / D converter is input, the output value of the A / D converter at that time, and the A / D converter before laser irradiation obtained in advance Difference processing means for calculating the difference between the output values as a monitor value of the laser beam;
With
6. The abnormality detection unit according to claim 1, wherein the abnormality detection unit determines that a laser beam has been detected when the monitor value by the difference processing unit is equal to or greater than a threshold value during abnormality determination. Laser processing equipment.   7. The abnormality detection unit according to claim 6, wherein the abnormality detection unit determines that a laser beam has been detected when a state in which the monitor value by the difference processing unit is equal to or greater than a threshold value continues for a predetermined time or more during abnormality determination. Laser processing equipment.

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