JP2010207901A - Laser beam machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining device provided with a laser beam monitoring means for machining, which can guarantee reliability even for use over a long period of time, further, can effectively discriminate not only the disconnection of an optical fiber propagating a laser beam for machining but also wear or the like of an optical element incorporated into a laser beam generating source. <P>SOLUTION: The laser beam monitoring means for machining comprises: an optical fiber for beam return for returning a part of a laser beam for machining propagated to the head part for machining to the device body part; and a return beam sensor which is located at the device body part, photoelectrically converts a return beam emitted from the optical fiber for beam return, and detects the same. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus suitable for laser processing such as laser welding, laser cutting, laser drilling, and the like. In particular, the apparatus main body and a laser processing head are separated, and an optical fiber is interposed between them. The present invention relates to a laser processing apparatus which is connected by a cable including the above.

  Laser processing apparatuses suitable for laser processing such as laser welding, laser cutting, laser drilling, and the like have been conventionally known.

  This type of apparatus has an apparatus main body, a laser processing head, and a cable connecting the apparatus main body and the laser processing head.

  The apparatus main body includes at least a laser light source that generates a processing laser beam and a shutter that can turn on and off the processing laser beam emitted from the laser light source. The cable includes an optical fiber for propagating the processing laser light that is turned on and off via the shutter of the apparatus main body to the laser processing head. The laser processing head portion includes an optical system for condensing and irradiating a processing laser beam introduced through the optical fiber in the cable onto the processing object.

  Furthermore, this apparatus monitors the state of the laser beam for processing propagated to the laser processing head section via the optical fiber in the cable in conjunction with the on / off state of the shutter in the apparatus main body section. The processing laser light monitoring means is provided so that abnormalities such as disconnection of the optical fiber for propagating the processing laser light and wear of the optical elements in the apparatus main body can be determined and appropriate measures can be taken. It is configured.

  Conventionally, as a processing laser beam monitoring means, there is a sensor in the laser processing head section that photoelectrically converts and detects a part of the processing laser beam propagated to the processing head section. A return electric signal line for returning the obtained electric signal from the laser processing head part to the apparatus main body part, and an optical fiber based on the electric signal returned through the electric signal line for return A device for determining the disconnection is known (for example, see Patent Document 1).

  In addition, for the purpose of detecting disconnection of the optical fiber that propagates the processing laser beam, the apparatus main body and the laser processing head are connected by a reciprocating pair of detection optical fibers, and the strength of the detection optical fiber is processed. This is set to be equivalent to the optical fiber of the laser beam, and determines whether the detection-dedicated light incident on the forward optical fiber from the device body is reflected in the laser processing head and emitted from the backward optical fiber Is also known (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 10-38751 JP 2000-42771 A

  However, in the former of the above-described conventional techniques, as long as the photoelectric conversion action in the sensor is normal, an electric signal having a pulse train corresponding to the pulse train of the processing laser beam can be obtained. Based on the signal, it is possible to determine not only the disconnection of the optical fiber that propagates the processing laser beam, but also the wear and tear of the optical element incorporated in the laser beam generation source. Since there is no way to do this, it must be said that the reliability in use over a long period of time is relatively low.

  On the other hand, in the latter of the above-described prior art, because the detection-dedicated light itself sent by the forward optical fiber is returned by the return optical fiber, there is no sensor with a photoelectric conversion action in the middle, Although the reliability over the long-term use is high by that amount, on the other hand, the light sent to the laser processing head is a detection-dedicated light different from the processing laser light, so the light propagating the processing laser light. Although it is effective for determining the disconnection of the fiber, it cannot be used for determining the wear of an optical element included in the light source of the processing laser beam.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to guarantee the reliability even for long-term use and to transmit the laser beam for processing. An object of the present invention is to provide a laser processing apparatus provided with a processing laser light monitoring means capable of effectively determining not only the fiber breakage but also the wear and the like of an optical element incorporated in a laser light source.

  Other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description of the specification.

  The above technical problem is considered to be effectively solved by a laser processing apparatus having the following configuration.

  That is, this apparatus has an apparatus main body, a laser processing head, and a cable connecting the apparatus main body and the laser processing head, and the apparatus main body includes a laser beam for processing. And at least a shutter capable of turning on and off a processing laser beam emitted from the laser light source, and the cable is for processing that is turned on and off via the shutter of the apparatus main body. An optical fiber for propagating the laser beam to the laser processing head portion is included, and the laser processing head portion is used for processing introduced through the optical fiber in the cable. An optical system for condensing and irradiating the laser beam onto the object to be processed is included, and further, the additional light propagated to the laser processing head through the optical fiber in the cable. A laser processing apparatus having a processing laser light monitoring means for monitoring the state of the laser light for use in conjunction with the on / off state of the shutter in the apparatus main body, wherein the processing laser light monitoring means A light return optical fiber for returning a part of the processing laser beam propagated to the processing head part to the apparatus main body part, and the light returning light in the apparatus main body part. And a return light sensor that detects the return light emitted from the fiber by photoelectric conversion.

  According to such a configuration, the return light emitted from the optical fiber for returning light is a part of the processing laser light propagated to the processing head portion. A pulse train corresponding to the pulse train of the processing laser beam is included. Therefore, according to the electrical signal obtained from the return light sensor that photoelectrically converts the return light, not only the disconnection of the optical fiber that propagates the processing laser light but also the wear of the optical element incorporated in the laser light generation source, etc. Can also be determined.

  Moreover, since a part of the laser beam for processing itself is returned as return light, there is no need for an age-degraded component such as a photoelectric sensor on the side of the laser processing head, so that it can be used for a long time. Reliability can be guaranteed.

  As a preferred embodiment of the above-described apparatus, the optical fiber for returning light may be included in the cable.

  According to such a configuration, when some strong load is applied to the cable and the optical fiber for sending the processing laser light to the laser processing head section is broken, the optical return is accompanied with this. Since the optical fiber will also be disconnected, such a disconnection accident can be more reliably determined.

  At this time, an optical coupling is made between the exit end of the processing optical fiber and the entrance end of the return optical fiber to the end coupling portion for coupling the end of the cable and the head for laser processing. If the optical element for doing so is included, the optical fiber for processing and the optical fiber for returning light can be easily optically coupled simply by inserting and fixing the cable to the terminal coupling portion.

  According to the present invention, the return light emitted from the optical fiber for returning light is a part of the processing laser light propagated to the processing head portion. A pulse train corresponding to the pulse train of the laser beam for use is included. Therefore, according to the electrical signal obtained from the return light sensor that photoelectrically converts the return light, not only the disconnection of the optical fiber that propagates the processing laser light but also the wear of the optical element incorporated in the laser light generation source, etc. In addition, since a part of the processing laser light itself is returned as the return light, there is no need for an age-degraded part such as a photoelectric sensor on the side of the laser processing head part. Reliability can be assured even for long-term use.

It is a block diagram which shows the whole laser processing apparatus concerning this invention. It is an expanded sectional view of a laser processing head part. It is an expanded sectional view of a termination joint part. It is explanatory drawing which shows an example of the monitoring aspect based on a return light.

  Hereinafter, a preferred embodiment of a laser processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing the entire laser processing apparatus according to the present invention. As shown in the figure, the laser processing apparatus includes an apparatus main body 1, a laser processing head 2, and a cable 3 that connects the apparatus main body 1 and the laser processing head 2. The Here, the length of the cable 3 can be about several m to 50 m.

  The apparatus main body 1 includes a laser light source (described later in detail) that generates a processing laser beam, and a shutter that can turn on and off the processing laser beam emitted from the laser light source (in the figure, an external shutter 113 corresponds). ) And are included.

  The laser light source will be described in detail. Reference numeral 101 denotes a guide light oscillator, which emits a HeNe laser as guide light. The laser beam emitted in this way is introduced into the oscillator of the YAG laser beam, which is a processing laser beam, via the folding mirrors 102 and 103. That is, in the YAG laser oscillator, the first resonator shutter 105, the first condenser 106, and the second resonator shutter 107 are arranged between the resonator (HR) 104 and the resonator (OC) 108. Composed.

  The YAG laser beam, which is the processing laser beam thus obtained, passes through the second condenser 109, the folding mirror 110, the folding mirror 111, the energy monitor 112, the external shutter 113, and the incident optical unit 114, and then the cable. 3 is introduced.

  The apparatus main body 1 corresponds to the four laser processing head units 2, and only one of them (A system) is shown in the figure. As indicated by broken lines in the figure, an energy monitor 112, an external shutter 113, and an incident optical unit 114 are also provided for the other B system, C system, and D system.

  Switching to each of these systems (A system, B system, C system, D system) selectively operates the three optical path switches 116, 117, 118 interposed in the optical path from the folding mirror 110 to the folding mirror 113. To be implemented. Reference numerals 119a, 119b, 119c, and 119d denote incident observation optical units in the A system, the B system, the C system, and the D system, respectively.

  In the apparatus main body 1, a return light sensor unit 115 is newly provided in association with the present invention. The return light sensor unit 115 is provided with four incident ports 115a, 115b, 115c, and 115d corresponding to the A system, B system, C system, and D system, respectively. These incident ports 115a to 115d can be connected to return optical fibers 32 of each system branched from the cable 3.

  In the return light sensor unit 115, four photoelectric sensors (not shown) are built in corresponding to the respective incident ports 115a, 115b, 115c, and 115d. Each of these photoelectric sensors converts the return light introduced from each of the incident ports 115a, 115b, 115c, and 115d into an electric signal having a corresponding intensity. Thus, the electrical signal obtained by the conversion is subjected to a predetermined monitoring operation described later.

  On the other hand, as shown in FIG. 2, in the cable 3, a processing fiber 31 for propagating the processing laser light to the laser processing head portion 2 and the processing propagated to the processing head portion 2. A return light fiber 32 for returning light for returning a part of the laser light for use to the apparatus main body 1 is accommodated. Such a cable 3 is coupled to the laser processing head unit 2 via the terminal coupling unit 21.

  The laser processing head unit 2 includes a first lens unit 22 having a collimator function for converting processing laser light emitted from the end of the processing fiber 31 into parallel light, and parallel light beams generated by the first lens unit 22. A second lens unit 23 for condensing the irradiated laser beam for processing and irradiating it on a workpiece not shown is incorporated. In this way, the laser beam L is irradiated to a workpiece (not shown) by the action of the second lens unit 23, whereby laser processing such as laser welding, laser cutting, and laser drilling is appropriately performed. Become.

  An enlarged cross-sectional view of the end coupling portion 21 is shown in FIG. As shown in the figure, the terminal coupling portion 21 is configured to fix the processing light fiber 31 and the return light fiber 32 in the cylindrical coupling portion case 21a via the fiber fixing bracket 21b. Yes. And between the front-end | tip part (output end part) of the fiber 31 for processing, and the front-end | tip part (incidence end part) of the return light fiber 32, they are for optical coupling between them with a predetermined | prescribed light transmissivity. A terminal optical element 21c is interposed. As a result, simply by inserting and fixing the cable 3 into the terminal coupling portion 21, the optical coupling between the exit end of the processing light fiber 31 and the incident end of the return light fiber 32 can be easily performed with a predetermined light transmissibility. It can be made to.

  Therefore, the processing laser light introduced from the incident optical unit 114 (see FIG. 1) into the processing fiber 31 in the cable 3 propagates through the processing fiber 31 and reaches the laser processing head unit 2. Then, the processing object is irradiated with the laser light L through the first lens unit 22 and the second lens unit 23.

  At the same time, a part of the processing laser light reaching the laser processing head unit 2 is introduced into the incident end of the return light fiber 32 and propagates through the return light fiber 32 to the apparatus main body unit 1. Returned, then branched off from the cable 3 and coupled to a corresponding one of the four incident ports 115a-115d of the return light sensor unit 115.

  Next, an explanatory diagram showing an example of a monitoring mode based on return light is shown in FIG. If an emission command is internally generated with respect to the processing laser beam (see (a) in the figure), an off-delay timer that defines the detection period is activated internally (see (b) in the same figure), and slightly less than that. After that, the output of the processing laser light pulse is started (see (c) in the figure).

  If there is no disconnection of the cable and all the optical elements in the apparatus main body are normal, in the optical path A selection state (see FIG. 4D), this is performed before the time t1 when the off-delay timer is turned off. Sensor A (input) appears with a pulse train corresponding to (see (e) in the figure). Therefore, the internal relay for detecting sensor A is actuated (see (g) in the figure), and normality determination is performed at time t1.

  On the other hand, if the corresponding pulse train does not appear in the laser beam returning before the time t1 due to the disconnection of the cable 3 or the like (see FIG. 5F), the abnormality determination is made when the time t1 has elapsed. Is performed (see (h) in the same figure), an emergency stop output is generated, and emission of the processing laser beam from the apparatus main body 1 is prohibited.

  Similarly, in the optical path B system in the non-selected state (see (i) in the same figure), it is observed if the cable is not disconnected during the input of the sensor B and all the optical elements in the apparatus main body are normal. When an inevitable pulse appears (see (j) in the figure), it is determined that the mirror is broken at time t2, and an output to that effect is issued (see (k) in the figure).

  Thus, according to such a monitoring mode, the electric pulses output from the four photoelectric sensors (A-system, B-system, C-system, and D-system) built in the return light sensor unit 115 are converted into the original pulses. By collating with the output pulse (light) (see (c) in the figure), it is possible to individually determine not only the disconnection of the cable 3 but also failure and deterioration of various optical elements built in the apparatus main body 1. It becomes possible.

  In addition, according to this embodiment, as shown in FIG. 2, the laser processing head portion 2 does not require any electro-optical elements or the like necessary for photoelectric conversion, This eliminates the need for consideration of aging deterioration, and enables reliable disconnection monitoring and optical element wear monitoring over a long period of time.

  In the above embodiment, both the processing fiber 31 and the return light fiber 32 are built in the cable 3, but these are bundled as two separate cables. Would be good.

  Moreover, in the above embodiment, it was configured as an apparatus that handles four processing laser beams consisting of the A system, the B system, the C system, and the D system. Of course it is good.

  The present invention relates to a laser processing apparatus in which an apparatus main body part and a laser processing head part are separated and connected between them by a cable including an optical fiber, in which a cable breakage or wear of an optical element included in a laser light source is detected. Can be used for.

DESCRIPTION OF SYMBOLS 1 Apparatus main body part 2 Laser processing head part 3 Cable 21 Termination coupling part 21a Joint part case 21b Fiber fixing bracket 21c Termination optical element 22 1st lens unit 23 2nd lens unit 31 Processing light fiber 32 Return light fiber 101 Guide Light Oscillator 102 Folding Mirror 103 Folding Mirror 104 Resonator (HR)
105 First resonator shutter 106 First condenser 107 Second resonator shutter 108 Resonator (OC)
109 Second condenser 110 Folding mirror 111 Folding mirror 112 Energy monitor 113 External shutter 114 Incident optical unit 115 Return light sensor unit 115a to 115d A system to D system incident port 116 to 118 Optical path switch 119a to 119d Incident observation optical Part L Laser light

Claims (3)

An apparatus main body, a laser processing head, and a cable connecting the apparatus main body and the laser processing head.
The apparatus main body includes at least a laser light source that generates laser light for processing, and a shutter that can turn on and off the processing laser light emitted from the laser light source,
The cable includes an optical fiber for propagating a laser beam for processing, which is turned on / off via a shutter of the apparatus main body, to the laser processing head unit, and the laser processing head unit Includes an optical system for condensing and irradiating a processing laser beam introduced through the optical fiber in the cable onto an object to be processed, and further including an optical fiber in the cable. A laser processing apparatus having processing laser light monitoring means for monitoring the state of the processing laser light propagated to the laser processing head section via the on / off state of the shutter in the apparatus main body section Because
The processing laser light monitoring means comprises:
An optical fiber for returning light for returning a part of the processing laser light propagated to the processing head part to the apparatus main body part;
A laser processing apparatus, comprising: a return light sensor that is in the apparatus main body and photoelectrically converts and detects return light emitted from the optical fiber for returning light. The laser processing apparatus according to claim 1, wherein the optical fiber for returning light is included in the cable. An end coupling portion for coupling the end of the cable and the laser processing head is for optically coupling between the exit end of the processing optical fiber and the entrance end of the return optical fiber. The laser processing apparatus according to claim 2, wherein the optical element is included.

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