JP6131146B2 - Laser nozzle and laser processing head - Google Patents

Description

  The present invention relates to a laser nozzle that can be attached to and detached from the tip of a laser processing head in a laser processing machine, and a laser processing head including the laser nozzle. More specifically, the present invention relates to a laser nozzle and a laser processing head that can detect an abnormally high temperature when the laser nozzle rises to an abnormally high temperature.

  A nozzle (laser nozzle) is detachably and replaceably provided at the tip of the laser processing head in the laser processing machine. At the time of laser processing by a laser processing machine, the laser nozzle is disposed close to the laser processing position of the workpiece, and is constantly heated by, for example, adhesion of sputtering, reflected light of laser light, radiant heat, etc., resulting in a high temperature. It is known. When the laser nozzle becomes an abnormally high temperature, the laser processing accuracy and the components in the laser processing head are adversely affected, so that a cooling fluid (for example, air) is jetted onto the laser nozzle ( For example, see Patent Document 1). It has also been proposed to provide a laser nozzle with a sensor for detecting a temperature rise of the laser nozzle (see, for example, Patent Documents 2 and 3).

JP 2002-273591 A Japanese Unexamined Patent Publication No. 56-41092 JP-A-3-27889

  The configuration described in Patent Document 1 is a configuration in which cooling air is ejected from the laser processing head side to the laser nozzle. Therefore, under normal conditions, the cooling of the laser nozzle is maintained, and the laser nozzle does not reach an abnormally high temperature of, for example, 200 ° C. or higher. However, if a part of the laser light irradiates the inner peripheral surface of the laser nozzle due to, for example, an optical path abnormality of the laser light, the temperature balance may be lost and the temperature may become abnormally high. In this case, since means for detecting that the laser nozzle has become abnormally high temperature is not provided, various problems may occur depending on the processing accuracy of laser processing and heat conduction to the components of the laser processing head.

  Patent Documents 2 and 3 propose that a temperature sensor is provided in the laser nozzle. Therefore, in the configuration described in Patent Document 1, it is conceivable to provide a temperature sensor in the laser nozzle.

  However, as is well known, the laser nozzle is a consumable part and, depending on the processing conditions, is replaced with a separate laser nozzle. Therefore, it is difficult to provide a sensor in the laser nozzle in consideration of wiring connection when the laser nozzle is provided with a sensor. Further, the sensor provided in the laser nozzle is likely to be damaged by sputtering or the like scattered during laser processing. Therefore, it is difficult to provide a temperature sensor in the laser nozzle.

  The present invention has been made in view of the above-described problems, and is a laser nozzle that can be attached to and detached from the tip of a laser processing head, and can be attached to and detached from the laser processing head on the upper surface of the nozzle body of the laser nozzle. The fluid ejecting hole expands when the nozzle body reaches a predetermined temperature or higher, corresponding to the position of the fluid ejection hole from which the cooling air is ejected from the laser processing head to the nozzle body. A thermal expansion member that can be freely closed is provided on the upper surface of the nozzle body.

  The laser processing head to which the laser nozzle can be attached and detached is an abnormality for detecting an increase in pressure in the fluid path or a decrease in the flow rate of the fluid in the fluid path connecting the fluid supply source and the fluid ejection hole. It is provided with a detection sensor.

  Further, the laser processing head is capable of detachably attaching the laser nozzle, and includes an expansion detection means for detecting that the thermal expansion member provided in the nozzle body has expanded. .

  According to the present invention, since the laser nozzle is provided with a thermal expansion member that expands when the laser nozzle becomes abnormally high in temperature, it is detected that the laser nozzle is abnormally high by detecting expansion of the thermal expansion member. It is something that can be done.

1 is an explanatory cross-sectional view conceptually and schematically showing a configuration of a laser processing head according to an embodiment of the present invention. It is a plane explanatory view of a nozzle body.

  Hereinafter, the configuration of a laser nozzle and a laser processing head according to an embodiment of the present invention will be described with reference to the drawings. A laser processing head 1 according to an embodiment of the present invention includes a cylindrical processing head main body 3, and a nozzle main body 5 of a laser nozzle can be attached to and detached from the tip (lower end) of the processing head main body 3. Is provided. A female screw portion 9 is formed at the tip of the processing head main body 3 so that a male screw portion 7 as a mounting portion provided protruding from the upper surface of the nozzle main body 5 is detachably engaged. The configuration in which the nozzle body 5 is detachably attached to the machining head 3 is not limited to the relationship of the screw portion as described above, but can be detachable as in the relationship between the collet chuck and the tool shank. It is also possible to adopt a configuration for fitting.

  An annular fluid passage 11 is formed at the distal end of the processing head body 3, and a plurality of fluid ejection holes 13 opened at the distal end surface of the processing head body 3 communicate with the fluid passage 11. . The fluid ejection holes 13 are provided at equal intervals in the circumferential direction. In order to supply air to the fluid passage 11, an outer cylinder 14 is fitted to the outer periphery of the processing head main body 3, and the outer cylinder 14 is connected to the fluid passage 11. A passage 15 is formed. The communication path 15 is connected to a fluid supply source 19 such as an air source via a fluid path 17. The fluid path 17 is provided with an abnormality detection sensor 21 such as a pressure sensor that detects a change in pressure in the fluid path 17 or a flow rate sensor that detects a change in flow rate in the fluid path 17.

  The nozzle body 5 has a configuration in which the male screw portion 7 protrudes from the upper surface, and a thermal expansion member 23 is provided at a position on the upper surface of the processing head body 3 corresponding to (opposed to) the fluid ejection hole 13. Is provided. The thermal expansion member 23 has a function of expanding several times to several tens of times in the thickness direction when the nozzle body 5 reaches a preset temperature, for example, 200 ° C. or more. For example, Sekisui Chemical Co., Ltd. Is commercially available under the name “Fibrok”. The thermal expansion member 23 has a function of expanding in the thickness direction when the nozzle body 5 is heated to an abnormally high temperature, for example, 200 ° C. or more, and closing the fluid ejection hole 13.

  In the configuration as described above, the workpiece W is irradiated with laser light through the nozzle hole 5A of the nozzle body 5 in the laser processing head 1 and the assist gas is ejected from the nozzle hole 5A to the workpiece W. Laser processing is performed. And in order to suppress that the nozzle main body 5 becomes high temperature at the time of laser processing, the air for cooling is supplied from the fluid supply source 19, and it is for cooling from the fluid ejection hole 13 with which the front end surface of the laser processing head main body 3 was equipped. The air is injected into the nozzle body 5. Therefore, the nozzle main body 5 is prevented from being cooled to a high temperature.

  By the way, the nozzle body 5 becomes high due to reflection of laser light from the laser processing part of the workpiece W, adhesion of spatter scattered from the laser processing part, radiant heat of the laser processing part, and the like, for example, 200 ° C. or more. When the temperature becomes high, the thermal expansion member 23 expands in the thickness direction, that is, the direction close to the fluid ejection hole 13 to close the fluid ejection hole 13. As described above, when the fluid ejection hole 13 is closed and the pressure in the communication path 15 and the fluid path 7 is equal to or higher than a preset set pressure or equal to or lower than a preset flow rate, The abnormality detection sensor 21 is activated. Then, laser oscillation in the laser processing machine is stopped and laser processing is stopped. Therefore, various inconveniences caused by the abnormally high temperature of the nozzle body 5 provided in the laser processing head 1 can be solved.

  By the way, the present invention is not limited to the embodiments as described above, and can be implemented in other forms by making appropriate modifications. That is, in the above description, the thermal expansion member 23 is described so as to correspond to each of the plurality of fluid ejection holes 13. However, it suffices if a change in pressure or a change in flow rate in the fluid passage 17 occurs when the appropriate fluid ejection holes 13 are closed. Therefore, it is also possible to provide the thermal expansion member 23 corresponding to only the appropriate number of fluid ejection holes 13 selected.

  In this case, the cooling air can be continuously ejected from the fluid ejection hole 13 that is not closed by the thermal expansion member 23 to the nozzle body 5. Therefore, it is possible to detect an abnormally high temperature of the nozzle body 5 while maintaining the cooling effect of cooling the nozzle body 5. The thermal expansion member 23 may be arranged in an annular shape or an arc shape along the arrangement of the fluid ejection holes 13 so as to correspond to the plurality of fluid ejection holes 13.

  As understood from the above description, when the thermal expansion member 23 expands to close the fluid ejection hole 13, the pressure or flow rate in the fluid passage 17 changes, and this change is detected by the abnormality detection sensor 21. Thus, it can be detected that the thermal expansion member 23 has expanded. Therefore, the abnormality detection sensor 21 corresponds to an expansion detection means for detecting that the thermal expansion member 23 has expanded.

  Here, as a configuration of the expansion detecting means for detecting that the thermal expansion member 23 has expanded, an appropriate position of the laser processing head 1, for example, the processing head main body 3, corresponding to the thermal expansion member 23 provided in the nozzle main body 5. It is also possible to adopt a configuration in which an electrical contact operated by the thermal expansion member 23 is provided on the distal end surface of the outer cylinder 14 or the distal end surface of the outer cylinder 14.

DESCRIPTION OF SYMBOLS 1 Laser processing head 3 Processing head main body 5 Nozzle main body 13 Fluid ejection hole 17 Fluid path 19 Fluid supply source 21 Abnormality detection sensor 23 Thermal expansion member

Claims (3)

  A laser nozzle that can be attached to and detached from the tip of the laser processing head, and includes an attachment portion that can be attached to and detached from the laser processing head on the upper surface of the nozzle body of the laser nozzle, and is cooled from the laser processing head to the nozzle body. Corresponding to the position of the fluid ejection hole from which air is ejected, the upper surface of the nozzle body is provided with a thermal expansion member that expands when the nozzle body reaches a predetermined temperature or more and can close the fluid ejection hole. A laser nozzle characterized by that.   A laser processing head to which the laser nozzle according to claim 1 can be attached and detached, wherein a pressure increase in the fluid path or a decrease in the flow rate of the fluid is detected in a fluid path connecting the fluid supply source and the fluid ejection hole. A laser processing head characterized by comprising an abnormality detection sensor for detecting a problem.   A laser processing head to which the laser nozzle according to claim 1 can be attached and detached, comprising an expansion detection means for detecting that the thermal expansion member provided in the nozzle body has expanded. Laser processing head.

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