JP2011079037A - Laser beam machining apparatus and method for monitoring laser beam machining condition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus which is capable of constantly monitoring the center of laser beam machining part, which has no burning damage of a photodetector of an optical fiber that receives reflected light from the center of the machining part, and which prevents a laser beam machining head from being damaged by preliminarily avoiding collision between the laser beam machining head and a workpiece, and also to provide a method for monitoring a laser beam machining condition using the apparatus. <P>SOLUTION: The laser beam machining apparatus is equipped with: a bend mirror holder in a laser beam machining head; a bend mirror that reflects a laser beam to a condensing lens and that transmits reflected light composed of visible light from the machining section, in the bend mirror holder; a light receiving end of an optical fiber for receiving the reflected light, in the back of the bend mirror; and a reflected light detection means that detects presence/absence of reflected light received by the light receiving end. The laser beam machining apparatus is characterized in that presence/absence of a workpiece is determined by the detection of reflected light by the reflected light detection means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing state monitoring method using the apparatus. More specifically, a laser processing apparatus capable of constantly monitoring the laser processing center and avoiding a collision between the laser processing head and the workpiece in advance to prevent damage to the laser processing head and a laser using the same The present invention relates to a machining state monitoring method.

  As an example of a laser processing apparatus including a laser processing head capable of monitoring a laser processing unit, for example, laser processing including a piercing hole penetration recognition device that recognizes whether or not a piercing hole has actually penetrated in a piercing process. There exists an apparatus (for example, patent document 1).

  In addition, as an example of a laser processing machine that prevents damage to the laser processing head due to the collision between the laser processing head and the work, there is one that detects the collision between the laser processing head and the work and then stops the operation of the laser processing machine. (For example, patent document 2).

  The outline of the piercing hole penetration recognition device described in Patent Document 1 is as follows. The tip of the optical fiber 3 is directed to the processing point of the workpiece on the side of the bend mirror 10 disposed above the condenser lens 7 inside the processing head 2. The visible light generated at the processing point at the time of piercing is made incident on the optical fiber 3, and the piercing hole processing is completed depending on the level of the incident light incident on the optical fiber 3. It is to recognize whether or not.

  The outline of the laser processing machine described in Patent Document 2 is that a torch (corresponding to a laser processing head part) 1 including a torch body 3 and an end effector (corresponding to a nozzle part) 4 is attached to the torch body 3. When an external force is applied to the end effector 4 from the workpiece W, that is, when the nozzle portion and the workpiece W collide, the suction fixing portion is detached and the nozzle portion is subjected to an external force. It is provided so as to be movable in the action direction, and the movement of the nozzle portion is detected by a sensor to stop the operation of the laser processing machine.

JP 2001-239388 A Japanese Patent Laid-Open No. 06-182569

  However, in the pierced hole penetration recognition device of Patent Document 1, the optical fiber 3 provided on the side of the bend mirror 10 disposed above the condenser lens 7 inside the processing head due to total reflection of the laser light generated at the time of defective cutting. There is a risk of burning the tip 3A of the.

  Normally, the bend mirror 10 is arranged at the center of the optical axis of the beam diameter of the incident laser light L, and collects an aperture (not shown) that regulates the outer periphery of the beam diameter of the laser light incident on the condenser lens 7. Generally, it is arranged above the lens 7 (on the incident side of the laser beam L).

  As described above, in the case of the piercing hole penetration recognition device in which the aperture (not shown) for restricting the outer periphery of the beam diameter of the laser beam is arranged, the light receiving unit 3A of the optical fiber 3 has the aperture (not shown). Since it is installed on the upper rear side (incident side of the laser beam L), the reflected light from the center of the processing part interferes with this aperture (not shown) and does not enter the light receiving part 3A of the optical fiber 3. Therefore, there is a demerit that the center of the processing part cannot be constantly monitored.

  In the collision prevention device in Patent Document 2, attention is paid to the collision with the workpiece. For example, when the torch is located at a location such as no workpiece (workpiece end) or a hole that has already been machined, the gap sensor detects it. The gap between the workpiece and the workpiece has become infinite, and it is impossible to cope with the phenomenon that the torch plunges below the workpiece pass line. In other words, monitoring the workpiece is inconvenient because it is replaced by watching the gap. In addition, once a collision occurs, there is an inconvenience that the end effector cannot be recovered immediately after being detached.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to constantly monitor the center of the laser processing section and to receive the reflected light from the center of the processing section. Provides a laser processing apparatus that can prevent the laser processing head from being damaged by preventing the laser processing head from being burned out, avoiding collision between the laser processing head and the workpiece in advance, and a laser processing state monitoring method using the same It is to be.

  As a means for solving the above-described problems, the laser processing apparatus according to claim 1 includes a laser processing head that can be moved and positioned in the X-axis, Y-axis, and Z-axis directions above the work table under the control of the NC controller. In the laser processing apparatus, a bend mirror holder is provided on the laser beam incident side of the condensing lens of the laser processing head, the laser beam from the laser light source is reflected on the bend mirror holder, and the laser is reflected. A bend mirror that transmits reflected light composed of visible light generated during processing is provided, a light receiving end of an optical fiber that receives the reflected light is provided behind the bend mirror, and the presence or absence of reflected light received by the light receiving end is determined. Reflected light detection means for detecting is connected to the other end of the optical fiber, and the presence / absence of a workpiece is determined by whether the reflected light detection means detects the reflected light. It is characterized in that.

  According to a second aspect of the present invention, there is provided the laser processing apparatus according to the first aspect, wherein the reflected light is reflected light during piercing.

  The laser processing state monitoring method according to claim 3 is a laser processing apparatus comprising a laser processing head that can be moved and positioned in the X-axis, Y-axis, and Z-axis directions above the work table under the control of the NC control device. A bend mirror holder is provided on the laser beam incident side of the condensing lens of the laser processing head, the laser beam from the laser light source is reflected on the bend mirror holder to the condensing lens, and visible light generated during laser processing A reflected light detecting means for detecting the presence or absence of reflected light received by the light receiving end portion, provided with a bend mirror that transmits the reflected light comprising: a light receiving end portion of the optical fiber that receives the reflected light behind the bend mirror; Is connected to the other end of the optical fiber, and the presence or absence of a work is determined by whether or not the reflected light detecting means detects the reflected light. Than is.

  According to a fourth aspect of the present invention, there is provided the laser processing state monitoring method according to the third aspect, wherein the reflected light is reflected light during piercing.

  A laser processing state monitoring method according to a fifth aspect is characterized in that, in the invention according to the third and fourth aspects, the operation of the laser processing apparatus is stopped when the reflected light is not detected. is there.

  According to the laser processing apparatus or the laser processing state monitoring method of the present invention, the laser processing center can be constantly monitored, and the light receiving portion of the optical fiber is not burned by the reflected light from the laser processing center at the time of defective cutting. In addition, it is possible to prevent the laser processing head from being damaged by avoiding a collision between the laser processing head and the workpiece in advance.

Explanatory drawing of the laser processing head part of the laser processing apparatus which concerns on this invention. 1 is a schematic diagram of a laser processing apparatus according to the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a part of a laser processing head 11 of a laser processing apparatus 1 (see FIG. 2) according to the present invention.

  Referring to FIG. 2, the laser processing apparatus 1 is an optical axis moving type laser processing apparatus, and a work table 5 is provided on an upper portion of a base 3. A track 7 extending in the X-axis direction is provided at both ends of the base 3 in the Y-axis direction, and an X-axis moving body 9 guided by the track 7 drives the work table 5 above the X-axis. It can be moved and positioned by means (not shown).

  In the X-axis moving body 9, a Y-axis moving body (not shown) provided with the laser processing head 11 is moved and positioned in the Y-axis direction (direction orthogonal to the X-axis) by a Y-axis driving means (not shown). It is provided freely.

  Referring to FIG. 1, a condensing lens 15 is provided above the nozzle 13 below the laser processing head 11, and above the condensing lens 15, that is, from a laser oscillator 17 (see FIG. 2). A bend mirror holder 19 is provided on the side where the laser beam L enters the condenser lens 15.

  The nozzle 13 below the laser processing head 11 has a known non-contact gap sensor (not shown) such as a capacitance sensor that keeps the distance between the nozzle tip and the workpiece W constant. It is provided.

  With the above configuration, the laser processing head 11 is controlled in the X-axis, Y-axis, and Z-axis directions (directions orthogonal to the X and Y axes) above the work table 5 under the control of the NC control device 21 of the laser processing apparatus 1. Positioning is possible.

  The bend mirror holder 19 reflects a laser beam L transmitted from the laser oscillator 17 through, for example, an optical system (not shown) including a plurality of bend mirrors to the condenser lens 15. 23 is provided.

  The above-described bend mirror 23 totally reflects the incident laser light L from the laser oscillator 17 to the condenser lens 15 and also reflects the reflected light L ′ made of visible light generated at the processing portion 25 of the workpiece W during laser processing. The one having the characteristic of partially transmitting is used.

  An annular aperture 27 is provided between the condenser lens 15 and the bend mirror 23 to restrict the outer diameter of the laser light L incident on the condenser lens 15.

  Behind the bend mirror 23 is provided a light receiving end portion of an optical fiber 29 for receiving the reflected light L ′ transmitted through the bend mirror 15. The other end of the optical fiber 29 is connected to reflected light detection means (not shown) provided inside the NC control device 21.

  The reflected light detection means has an optical sensor that converts light into a digital electrical signal, and is configured to detect the presence or absence of reflected light.

  With the above configuration, when reflected light is detected by the reflected light detection means during laser processing, it is determined that the workpiece is present in the processing portion 25 of the workpiece W, and the processing is continued, and the reflected light is not detected. In this case, it is determined that there is no workpiece or a hole is present in the machining section 25, and the operation of the laser machining apparatus is stopped by the NC control device 21.

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 3 Base 5 Work table 7 Orbit 9 X-axis moving body 11 Laser processing head 13 Nozzle 15 Condensing lens 17 Laser oscillator 19 Bend mirror holder 21 NC controller 23 Bend mirror 25 Processing part 27 Aperture 29 Optical fiber L Laser light L 'reflected light

Claims (5)

  In a laser processing apparatus having a laser processing head that can be moved and positioned in the X-axis, Y-axis, and Z-axis directions orthogonal to each other above the work table under the control of the NC control device, the laser of the condenser lens of the laser processing head A bend mirror holder is provided on the light incident side, and a bend mirror that reflects the laser light from the laser light source to the condenser lens and transmits the reflected light generated during laser processing is transmitted to the bend mirror holder. A light receiving end of an optical fiber that receives the reflected light is provided behind the bend mirror, and a reflected light detecting means that detects the presence or absence of reflected light received by the light receiving end is connected to the other end of the optical fiber. A laser processing apparatus, wherein the presence or absence of a workpiece is determined based on whether or not the reflected light detection means detects the reflected light.   The laser processing apparatus according to claim 1, wherein the reflected light is reflected light during piercing.   In a laser processing apparatus having a laser processing head that can be moved and positioned in the X-axis, Y-axis, and Z-axis directions orthogonal to each other above the work table under the control of the NC control device, the laser of the condenser lens of the laser processing head A bend mirror holder is provided on the light incident side, and a bend mirror that reflects the laser light from the laser light source to the condenser lens and transmits the reflected light generated during laser processing is transmitted to the bend mirror holder. A light receiving end of an optical fiber that receives the reflected light is provided behind the bend mirror, and a reflected light detecting means that detects the presence or absence of reflected light received by the light receiving end is connected to the other end of the optical fiber. And a laser processing state monitoring method, wherein the presence or absence of a workpiece is determined based on whether or not the reflected light detecting means detects the reflected light.   4. The laser processing state monitoring method according to claim 3, wherein the reflected light is reflected light during piercing.   5. The laser processing state monitoring method according to claim 3, wherein the operation of the laser processing apparatus is stopped when the reflected light is not detected.

Images