JP2008043989A - Laser beam machining device and laser beam machining method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hand laser beam machining device and a leaser beam machining method using the same by which the physical relationship to a workpiece can be detected by simple constitution and which has high safety and has in hands. <P>SOLUTION: In a laser beam machining device with which laser beam machining is performed by transmitting a laser beam to an outgoing optical part by a beam transmission part and emitting the laser beam onto the workpiece 20 by the outgoing optical part, the outgoing optical part has the torch body 100, a workpiece-detecting probe 4 which is attached to the tip of the torch body, condensing lens 2 with which the laser beam is emitted by focusing on a position at a prescribed distance from the tip of the torch body, a first circuit for determining a distance by inputting a signal varied on the basis of the distance between the probe and the workpiece by giving a power source to the probe, a second circuit for detecting contact of the probe with the workpiece on the basis of the signal from the probe and a control part 8 for controlling the oscillation of the laser beam by the contact of the probe with the workpiece and the distance between the probe and the workpiece. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method using the same, and more particularly to a laser processing apparatus including a hand-held emission optical unit and a laser processing method using the same.

  An operator may hold a hand-held emission optical part and perform welding work by temporary fixing welding or the like, which is not always suitable for laser welding by an automated facility. In this case, in order to protect workers and the like from the emitted high laser energy and perform laser processing with stable quality, the positional relationship between the emission optical unit and the workpiece is detected, and this positional relationship is within a predetermined range. Laser processing equipment is generally equipped with a safety function so that laser irradiation can be performed only when it is within, so that unnecessary parts are not irradiated with laser light, and workers are not exposed to inadvertent laser exposure. The

  As a method for detecting the positional relationship between the emission optical unit and the workpiece, for example, Patent Document 1, Patent Document 2 and Patent Document 3 include contact type and / or non-contact type sensors as output optical units (Patent Document 1). 3 to 3 are referred to as “laser torches.” (Hereinafter referred to as torches), and a technique for detecting a workpiece is disclosed.

  In the torch disclosed in Patent Document 1, the exit end of the fiber that guides the laser beam generated by the laser oscillator is positioned in a gripping cylinder having a tapered nozzle at the front end, and forward of the exit end from the exit end. A condensing lens is provided so that the emitted laser light is focused near the front end surface of the nozzle, and the laser oscillator is oscillated when the front end of the nozzle comes into contact with the workpiece. As a result, the laser beam is correctly focused on the workpiece.

  Further, Patent Document 2 aims to improve the durability of the nozzle provided at the front end of the torch, and as a means for detecting that the front end of the torch has approached a certain distance to the workpiece, the front end of the nozzle When a contact type sensor that protrudes ahead of the required amount is provided, when compressed gas is introduced into the nozzle and this compressed gas is ejected from the front end of the nozzle, and the front end of the nozzle approaches the workpiece to a certain distance Provided with a pressure sensor that operates by detecting that the pressure of the compressed gas is greater than a preset pressure, and a coil is attached to the torch, and changes in the inductance of the coil are detected to operate. An inductive proximity sensor (inductive sensor), and an electrostatic proximity sensor that operates by detecting a change in capacitance between the front end of the nozzle and the workpiece (electrostatic sensor) It has been disclosed that is provided. These torches are such that laser light is generated when it is detected that the front end of the torch has approached a certain distance with respect to the workpiece while the hand switch is turned on.

  In addition, the YAG laser torch disclosed in Patent Document 3 is a first detection means that detects the presence or absence of a workpiece before the start of machining and a non-contact or contact-detectable first detection means, and a non-detection that detects the presence or absence of a workpiece during machining. It becomes effective only when the presence of the workpiece is detected by the first detection means and the two detection means of the second detection means capable of detecting contact, and opens and closes the shutter of the optical path of the YAG laser light. And a confirmation switch for turning on / off the YAG laser transmitter. These torches are such that laser light is generated by pressing a laser emission switch when the first detection means detects the presence of a workpiece. In addition, when the second detection means detects that there is no workpiece during processing, the YAG laser light emission is set to be blocked.

  In Patent Document 3, before starting processing, when the confirmation switch is turned on, the YAG laser transmitter is turned on, and at the same time, visible light is emitted to the workpiece, and a visible light detector is used as the first detection means. This is used to detect the presence or absence of the workpiece before the start of processing by detecting the reflected light of visible light, and as a second detection means, a detector that detects the reflected light of the YAG laser or a target during laser processing. A torch for detecting the presence or absence of a workpiece during laser processing by using a detector that detects light and infrared rays in a visible light region generated in a processing portion is disclosed.

  In addition, a torch provided with a limit switch that operates to contact and press the tip of the torch against the workpiece instead of the visible light detector is also disclosed as the first detection means described above. In this torch, even when the contact between the limit switch and the workpiece is lost, the YAG laser is continuously emitted while the second detection means detects the light emission of the workpiece during laser machining. It has become.

  Furthermore, a torch provided with an electrostatic sensor as the first detection means is also disclosed. This torch detects whether or not there is a workpiece before the start of machining, depending on whether the workpiece is metal or non-metal, and only when the workpiece is located within the detection range of the electrostatic sensor The light can be emitted.

  Moreover, what provided proximity sensors, such as a limit switch and an electrostatic type sensor, in the torch is also disclosed. This torch uses a proximity sensor to determine whether the workpiece is made of metal or non-metal before starting machining, and then determines whether or not YAG laser light can be emitted by operating a limit switch. The YAG laser is emitted only when the workpiece is located within the detection range of the proximity sensor.

JP-A-5-318158 JP-A-5-318159 JP 2002-239771 A

  However, the above-described prior art has the following problems. In the torch disclosed in Patent Document 1, laser oscillation stops when the contact between the nozzle and the workpiece is lost, and therefore continuous machining may not be possible when the workpiece has a curved surface, a step, or the like.

  Further, the technique disclosed in Patent Document 2 detects that the torch has approached the workpiece using a contact type, pressure type, dielectric type or electrostatic type sensor, and after the detection, laser oscillation is performed. Unlike the torch disclosed in Patent Document 1, laser irradiation is not possible unless the tip of the torch touches the workpiece. There is a possibility that laser processing can be performed. However, in the technique disclosed in Patent Document 2, in the state in which the hand switch is turned on, the sensor approaches the workpiece or other substance that can be sensed in some way, and the sensor approaches the workpiece. If this is detected, there is a risk that unintended laser light may be emitted, and safety cannot always be ensured.

  Further, since the torch disclosed in Patent Document 3 is equipped with two types of detectors, the torch has a complicated structure, and the adjustment and maintenance of the two types of sensors are complicated. There is.

  The present invention has been made in view of such problems, and it is possible to detect a positional relationship with a workpiece with a simple configuration, and to provide a highly safe hand-held laser processing apparatus and a laser processing method using the same. The purpose is to provide.

  In the laser processing apparatus according to the present invention, the laser beam is transmitted to the emission optical unit by the light transmission unit, and the workpiece is irradiated with the laser beam by the emission optical unit to perform laser processing. The projecting optical unit includes a torch body, a workpiece detection probe provided at the tip of the torch body, a condensing lens that emits laser light with a focus at a predetermined distance from the tip of the torch body, and A first circuit that obtains the distance by applying a power to the probe and inputting a signal that changes based on a distance between the probe and the workpiece; and the probe based on a signal from the probe The second circuit for detecting contact with the workpiece, the contact of the probe with the workpiece and the distance between the probe and the workpiece, A control unit for controlling the vibration, characterized by having a.

  As a result, the presence or absence of the workpiece before laser processing and the distance between the workpiece detection probe and the workpiece during laser processing can be detected by a single workpiece detection sensor. The maintainability of the processing apparatus is improved.

  It is preferable that the control unit does not oscillate the laser beam until it detects that the probe and the workpiece are in contact with each other.

  Thereby, the possibility that unintended laser light is emitted is reduced, and a highly safe laser processing apparatus can be obtained.

  The probe is a probe of a capacitive sensor, and a signal that changes based on the distance between the probe and the workpiece is a capacitance of the capacitance between the probe and the workpiece. It may be a detection signal.

  The probe is a probe of an eddy current sensor, the probe has a sensor coil, and a signal that changes based on a distance between the probe and the workpiece is a detection signal of an impedance of the sensor coil. It may be.

  It is preferable that a hand switch for instructing laser irradiation is provided on the torch body.

  Further, a foot switch for instructing laser irradiation may be provided at a position close to the torch body.

  Further, a safety switch for shutting down the entire apparatus may be provided at the torch body or at a position close to the torch body.

  The laser processing method according to the present invention includes a step of supplying power to a workpiece detection probe to detect contact between the probe and the workpiece, and a controller when necessary to detect the contact. A step of supplying a gas to the workpiece, a step of raising an excitation current of a laser oscillator to a level at which a necessary output is obtained by the control unit, a laser processing preparation stage, and the workpiece detection probe. When detecting that the workpiece is located within a predetermined distance range and receiving a laser emission command from the control unit, a laser is oscillated to start laser processing, and the workpiece The laser processing is a two-step process comprising the step of continuously performing the laser processing while the distance between the detection probe and the workpiece is within the predetermined distance range. It is characterized in.

  According to the present invention, a single workpiece detection sensor detects contact between a workpiece detection probe and a workpiece before the start of laser machining, and between the workpiece detection probe and workpiece during laser machining. By performing the distance detection, the configuration of the output optical unit is simplified, and the price of the output optical unit can be reduced and the maintainability can be improved.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings. First, a first embodiment of the present invention will be described. FIG. 1 is an explanatory diagram showing the configuration of the laser processing apparatus according to the present embodiment, FIG. 2 is an explanatory diagram showing the configuration of the torch body 100, and FIG. 3 is an example of C / V voltage output of the capacitance detection circuit 7. 4 is a control sequence example of a laser processing preparation stage of the laser processing apparatus according to the present embodiment, FIG. 5A is a control sequence example of a laser processing process of the laser processing apparatus according to the present embodiment, and FIG. FIG. 5B is a graph showing an example of setting the detection signal level range of the C / V voltage output.

  In the laser processing apparatus according to the present embodiment, as shown in FIG. 1, the laser light output from the laser oscillator 11 is transmitted by an optical transmission unit 15 such as an optical fiber, and the laser light 6 is emitted from the tip of the torch body 100. Is done. As shown in FIG. 2, the torch body 100 has a tapered cylinder-shaped gripping cylinder insulating part 3 attached to the tip of the gripping cylinder 1, and a workpiece formed of a conductor at the tip of the gripping cylinder insulating part 3. A sensor probe 4 of a capacitance type sensor is provided as a detection probe. The sensor probe 4 also serves as a torch. In addition, a condensing lens 2 is arranged inside the gripping cylinder 1 so as to be coaxial with the central axis of the gripping cylinder 1 and the optical axis of the laser beam, and the light output from the laser oscillator 11 is output by the condensing lens 2. The laser beam 6 transmitted by the transmission unit 15 is emitted while being focused at a predetermined distance from the tip of the torch body 100. Laser processing is performed on the workpiece 20 by placing the grounded metal workpiece 20 at the focal position (condensing position).

  Further, the torch body 100 is connected to the process gas supply unit 12, and the gas control electromagnetic valve 13 is opened as necessary during laser processing or the like, and the workpiece 20 is processed from the tip of the sensor probe 4 (torch). An assist gas or the like is supplied to the location. Further, the torch body 100 and the laser oscillator 11 are cooled by an air cooling chiller 14 as necessary. Further, the torch body 100 is provided with a hand switch 5 for an operator to instruct laser irradiation, whereby the torch body 100 is configured.

  The hand switch 5 is connected to a processing device control unit 8 as a control unit. A C / V voltage output 75 and a contact detection voltage output 76 output from the capacitance detection circuit 7 connected to the sensor probe 4 are input to the processing device controller 8. Further, a foot switch 16 is provided at a location close to the torch body 100, and the foot switch 16 is connected to the processing device control unit 8. The foot switch 16 has the same function as the hand switch 5, and the operator can also instruct laser irradiation by operating the foot switch 16 instead of operating the hand switch 5.

  The capacitance detection circuit 7 applies an AC signal for measuring the capacitance Cx from the detection oscillator 71 between the sensor probe 4 and the workpiece 20, and the sensor probe 4 and the workpiece 20 Based on the signal from the first circuit that detects the capacitance Cx that changes based on the distance between them, calculates the distance between the sensor probe 4 and the workpiece 20 from the capacitance Cx, and the sensor probe 4 And a second circuit that detects contact between the sensor probe 4 and the workpiece 20. The voltage induced in the capacitance Cx between the sensor probe 4 and the workpiece 20 by the AC signal applied between the sensor probe 4 and the workpiece 20 from the detection oscillator 71 is a C / V amplifier. Amplified by 72, converted to a C / V voltage output 75, which is a DC voltage signal, by a C / V converter 73, and output to the machining apparatus controller 8. The capacitance Cx changes according to the distance between the sensor probe 4 and the workpiece 20, and as shown in FIG. 3, as the distance between the sensor probe 4 and the workpiece 20 decreases, C / The V voltage output 75 increases.

  On the other hand, when the sensor probe 4 comes into contact with any substance, this output voltage is amplified by the contact detection amplifier 74 and is output to the processing device controller 8 as the contact detection voltage output 76. At this time, when the substance contacted with the sensor probe 4 is the workpiece 20, since the workpiece 20 is a metal, a large output voltage different from the normal output value detected at the time of non-contact is obtained.

  The processing device control unit 8 determines the detection signal levels of the C / V voltage output 75 and the contact detection voltage output 76 to determine whether laser oscillation is possible. The predetermined detection signal level range of the C / V voltage output 75 and the predetermined detection signal level of the contact detection voltage output 76 are set according to the material and / or shape of the workpiece 20, and as described above, If the predetermined detection signal level of the contact detection voltage output 76 is set based on the detection signal level of the contact detection voltage output 76 when the sensor probe 4 and the workpiece 20 are in contact with each other, the substance with which the sensor probe 4 has contacted is set. Since the detection signal level of the contact detection voltage output 76 in the case of non-metal does not exceed this predetermined detection signal level, it can be set so that laser irradiation is not performed even if the sensor probe 4 contacts non-metal. Thus, the safety is improved without the operator being irradiated with laser light. Further, a predetermined detection signal level range of the C / V voltage output 75 is set based on the detection signal level of the C / V voltage output 75 when the workpiece 20 is located at the condensing position of the laser beam 6. For example, the in-focus position during laser processing can be detected.

  Further, the processing device control unit 8 constantly monitors an external interlock signal 9 related to safety measures such as a signal indicating that the operator wears protective equipment, and when this interlock signal 9 is valid, laser irradiation is performed. The command signal 10 is not output to the laser oscillator 11. At this time, the indicator lamp 18 can be turned on.

  In the laser processing apparatus according to the present embodiment, when the interlock signal 9 is not valid, the hand switch 5 (or the foot switch 16) is in an on state, and the processing apparatus control unit 8 detects the contact detection voltage output 76. When it is determined that the signal level has exceeded a predetermined value and then the detection signal level of the C / V voltage output 75 is determined to be within a predetermined range, it is determined that laser oscillation is possible, and a laser irradiation command signal 10 is output to the laser oscillator 11 and the workpiece 20 is irradiated with the laser beam 6.

  Further, as part of laser processing preparation, the processing device control unit 8 opens an oscillator external shutter (not shown) which is one of laser safety devices, opens a gas control electromagnetic valve 13 as necessary, and assist gas. Or the like from the torch (sensor probe 4) to the processing location of the workpiece 20, and has a function of raising the excitation current of the laser oscillator 11 to a level at which a necessary output can be obtained. Further, a safety switch 17 is connected to the processing device control unit 8, and the entire device can be shut down by pressing the safety switch 17 in an emergency or the like. Thereby, the laser processing apparatus according to the present embodiment is configured.

  Next, the operation of the laser processing apparatus according to this embodiment configured as described above will be described.

  When the operator turns on the hand switch 5 (or the foot switch 16) in a state where safety measures such as wearing protective equipment are taken and the sensor probe 4 is brought into contact with the workpiece 20, it is usually detected when there is no contact. A large output voltage different from the output value is detected. The contact detection amplifier 74 amplifies the output voltage and outputs the amplified output voltage as the contact detection voltage output 76 to the processing device control unit 8, so that the workpiece 20 exists in the processing device control unit 8 before laser processing. Detect that. At this time, the processing device control unit 8 opens an oscillator external shutter (not shown), which is one of laser safety devices, and processes the workpiece 20 from the torch (sensor probe 4) with an assist gas or the like as necessary. Preparation for laser processing is performed, such as supplying the laser beam to a location or raising the excitation current of the laser oscillator 11 to a level at which a necessary output can be obtained.

  Next, when the operator moves the sensor probe 4 away from the state in which the sensor probe 4 is in contact with the workpiece 20, the capacitance Cx changes according to the distance between the sensor probe 4 and the workpiece 20. The voltage induced in the electrostatic capacitance Cx is amplified by the C / V amplifier 72 and converted into a C / V voltage output 75 which is a DC voltage signal by the C / V converter 73 to the processing device control unit 8. Is output. When the processing device control unit 8 detects that the detection signal level of the C / V voltage output 75 is within a predetermined range, that is, determines that laser oscillation is possible, and the interlock signal 9 is not valid. The laser irradiation command signal 10 is output to the laser oscillator 11, and the laser light 6 output from the laser oscillator 11 enters the torch main body 100 via the optical transmission unit 15 such as an optical fiber.

  The laser beam 6 incident on the torch body 100 is emitted by the condenser lens 2 while focusing on a position at a predetermined distance from the tip of the torch body 100. When the workpiece 20 is present at this condensing position, the processing device control unit 8 is set so that the detection signal level of the C / V voltage output 75 is within a predetermined range. Thereby, the laser beam 6 is irradiated to the workpiece 20, and laser processing is performed. Even during laser processing, the processing apparatus control unit 8 constantly monitors the detection signal level of the C / V voltage output 75.

  When the operator turns off the hand switch 5 (or the foot switch 16) or the distance between the sensor probe 4 and the workpiece 20 is increased and the detection signal level of the C / V voltage output 75 is out of the predetermined range. The processing apparatus control unit 8 determines that laser oscillation is not possible, and stops outputting the laser irradiation command signal 10 to the laser oscillator 11. As a result, laser oscillation is stopped and laser processing is stopped.

  Next, a control sequence example of the laser processing apparatus according to the present embodiment will be described.

  First, the laser processing preparation stage will be described. First, in a state where safety measures such as wearing protective equipment are performed, the operator has a C / V voltage output 75 that is less than a predetermined detection signal level and a contact detection voltage output 76 is In a state where the level is less than a predetermined detection signal level (the sensor probe 4 and the workpiece 20 are not in contact), the sensor probe 4 of the torch body 100 is once brought into contact with the workpiece 20 and the laser processing preparation is completed. This is caused to be detected by the processing device control unit 8 (step 1). The processing device control unit 8 does not prepare for laser processing until the sensor probe 4 of the torch body 100 comes into contact with the workpiece 20. As a result, even if the sensor probe 4 approaches the workpiece 20 or other material in some form and the C / V voltage output 75 falls within the predetermined detection signal level range, the laser irradiation to the laser oscillator 11 is performed. The command signal 10 is not output, and there is no possibility that an unintended laser beam is emitted.

  When the contact detection voltage output 76 is equal to or higher than a predetermined detection signal level, the processing device control unit 8 that detects the presence of the workpiece 20 is an oscillator external shutter (not shown) that is one of laser safety devices. If necessary, assist gas or the like is supplied from the torch (sensor probe 4) to the processing portion of the workpiece 20, or the excitation current of the laser oscillator 11 is increased to a level at which a necessary output can be obtained. Preparation for laser processing is performed (step 2). This completes the laser processing preparation stage.

  Next, the laser processing process will be described. As shown in FIG. 5 (a), the worker has taken safety measures such as wearing protective gear (the interlock signal 9 is not in the ON state (step 1), and the gas check and the protective glasses check are Yes). In this state (step 2)), the hand switch 5 (or the foot switch 16) is turned on, and the sensor probe 4 of the torch body 100 in contact with the workpiece 20 is separated from the workpiece 20. To go. At this time, as shown in FIG. 5B, the machining apparatus control unit 8 determines that the workpiece 20 is close to the workpiece 20 according to the detection signal level of the C / V voltage output 75 (level 1). When it is determined that the C / V voltage output 75 is at a level 1 or less (step 3), the laser irradiation command signal 10 is transmitted to the laser oscillator. 11 (step 4), and the workpiece 20 is irradiated with the laser beam 6 (step 5).

  In all processes, the external interlock signal 9 related to safety measures such as a signal indicating that the operator wears protective equipment is constantly monitored by the processing device control unit 8, and the external interlock signal 9 is valid. The laser irradiation command signal 10 is not output. In any step, if the safety switch 17 is turned on, the entire apparatus is shut down.

  When the hand switch 5 (or the foot switch 16) is turned off, the sensor probe 4 is separated from the workpiece 20, and the detection signal level of the C / V voltage output 75 becomes less than level 2, or the sensor When the probe 4 approaches the workpiece 20 and the detection signal level of the C / V voltage output 75 exceeds level 1 (step 6), the laser oscillation is stopped (step 7). If the laser oscillation stop state continues for a predetermined time or longer, the supply of the assist gas is stopped and the oscillator external shutter (not shown) is also closed (step 8). Then, in order to start laser processing again, it starts again from the laser processing preparation stage shown in FIG.

  According to the present embodiment, the sensor probe 4 can detect contact between the torch body 100 and the workpiece 20 before the start of laser processing and detect the distance between the torch body 100 and the workpiece during laser processing. Therefore, the configuration of the torch body 100 can be simplified, and the price of the torch body 100 can be reduced and the maintainability can be improved.

  First, the contact between the torch body 100 and the workpiece 20 is confirmed, and then laser processing is performed only when the distance between the torch body 100 and the workpiece during laser processing is within a certain range. There are few mistakes, and at this time, it is confirmed whether or not the workpiece 20 is a metal. If the workpiece 20 is non-metallic, the laser beam is not emitted, so that the operator is irradiated with laser light. Therefore, laser processing with high safety can be realized.

  Next, a second embodiment of the present invention will be described. In the first embodiment described above, the workpiece detection sensor is a capacitance type sensor, whereas in the present embodiment, the workpiece detection sensor is an eddy current sensor. It has the same structure as one embodiment.

  In the laser processing apparatus according to this embodiment, a sensor probe of an eddy current sensor as a workpiece detection sensor is provided in front of a hand-held emission optical unit. This sensor probe includes a sensor coil, and generates a high-frequency magnetic field by flowing a high-frequency current through the sensor coil. If there is a workpiece in this magnetic field, magnetic flux passes through the surface of the workpiece due to electromagnetic induction, vertical eddy current flows, and the impedance of the sensor coil changes. The eddy current sensor measures the distance by the change of the oscillation state due to this phenomenon. As the distance between the sensor coil and the workpiece becomes closer, the oscillation amplitude becomes smaller and the phase deviation from the reference waveform becomes larger. . This change in amplitude and phase is detected, or the distance between the sensor probe and the workpiece is measured by rectifying the amplitude of oscillation and detecting it as a change in DC voltage.

  In the laser processing apparatus according to the present embodiment, the configuration, operation, and action other than using the eddy current sensor as the workpiece detection sensor are the same as those of the laser processing apparatus according to the first embodiment described above.

  According to the present invention, a single workpiece detection sensor can detect contact between the output optical unit and the workpiece before the start of laser machining and detect a focal point of the workpiece during laser machining. Therefore, the configuration of the emission optical unit is simplified, and the price of the emission optical unit can be reduced and the maintainability can be improved.

  In addition, the processing device control unit does not output a laser irradiation command signal until the worker brings the output optical unit into contact with the workpiece. First, the contact between the output optical unit and the workpiece is confirmed, and then the laser By adopting a control sequence with two stages of detecting the in-focus position during processing and performing laser processing, there are few mistakes, and at this time, it is confirmed whether the workpiece is metal. Since the laser beam is not emitted if the workpiece is non-metallic, the operator is not irradiated with laser light, and laser processing with high safety can be realized.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment, In the technical range grasped | ascertained from description of the claim of this invention, a various change is possible. There are also laser processing apparatuses that involve such changes, and are also included in the technical scope of the present invention.

It is explanatory drawing which shows the structure of the laser processing apparatus which concerns on 1st Embodiment of this invention. 3 is an explanatory diagram showing a configuration of a torch body 100. FIG. 6 is a graph showing an example of C / V voltage output of the capacitance detection circuit 7; It is an example of the control sequence of the preparatory stage of the laser processing of the laser processing apparatus which concerns on 1st Embodiment of this invention. (A) is a graph which shows the example of a control sequence of the laser processing process of the laser processing apparatus which concerns on 1st Embodiment of this invention, (b) shows the example of a setting of the detection signal level range of C / V voltage output.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Gripping cylinder 2; Condensing lens 3; Gripping cylinder insulation part 4; Sensor probe 5; Hand switch 6; Laser light 7; Capacitance detection circuit part 71; Detection oscillator 72; C / V amplifier 73; C / V converter 74; contact detection amplifier 75; C / V voltage output 76; contact detection voltage output 8; processing device controller 9; external interlock signal 10; laser irradiation command signal 11; laser oscillator 12; 13; Gas control solenoid valve 14; Air-cooled chiller 15; Optical transmission unit 16; Foot switch 17; Safety switch 18; Indicator light 20; Work piece 100; Torch body Cx; Between sensor probe 4 and work piece 20 Capacitance

Claims (8)

In a laser processing apparatus that transmits a laser beam to an emission optical unit by an optical transmission unit, and performs laser processing by irradiating the workpiece with the laser beam by the emission optical unit, the emission optical unit includes a torch body and the torch. A workpiece detection probe provided at the tip of the main body, a condensing lens that focuses and emits laser light at a predetermined distance from the tip of the torch main body, and supplies the probe with power to the probe; A first circuit for obtaining the distance by inputting a signal that changes based on the distance between the workpiece and the contact between the probe and the workpiece based on a signal from the probe. A second circuit for detecting, and a control unit that controls the oscillation of the laser light by the contact of the probe with the workpiece and the distance between the probe and the workpiece. Laser processing apparatus, characterized in that. The laser processing apparatus according to claim 1, wherein the control unit does not oscillate the laser beam until it detects that the probe and the workpiece are in contact with each other. The probe is a probe of a capacitive sensor, and a signal that changes based on a distance between the probe and the workpiece is a detection signal of a capacitance between the probe and the workpiece. The laser processing apparatus according to claim 1 or 2, wherein The probe is a probe of an eddy current sensor, the probe has a sensor coil, and the signal that changes based on the distance between the probe and the workpiece is a detection signal of the impedance of the sensor coil. The laser processing apparatus according to claim 1 or 2, wherein The laser processing apparatus according to claim 1, wherein a hand switch for instructing laser irradiation is provided on the torch body. The laser processing apparatus according to any one of claims 1 to 5, further comprising a foot switch that instructs laser irradiation at a position close to the torch body. The laser processing apparatus according to any one of claims 1 to 6, wherein a safety switch that shuts down the entire apparatus is provided in the torch body or a position close to the torch body. Supplying power to the workpiece detection probe to detect contact between the probe and the workpiece; and supplying gas to the workpiece as needed by the control unit when the contact is detected A step of increasing the excitation current of the laser oscillator to a level at which a necessary output can be obtained by the control unit, and a laser processing preparation stage, and the workpiece detection probe and the workpiece are at a predetermined distance Detecting the position within the range and receiving a laser emission command from the controller, the laser is oscillated to start laser processing, and the workpiece detection probe and the workpiece A laser processing method comprising: a step of performing the laser processing continuously while the distance is within the predetermined distance range; and a laser processing process comprising two steps: .

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