JP5997965B2 - Laser processing head - Google Patents

Description

  The present invention includes a condensing lens that condenses laser light emitted from a laser oscillator and irradiates the workpiece, and includes a protective glass for protecting the condensing lens, and further detects dirt on the protective glass. More particularly, the present invention relates to a laser processing head capable of detecting contamination over the entire surface of the protective glass.

  When laser processing such as laser cutting or laser welding is performed by irradiating a workpiece with a laser beam from a laser processing head provided in the laser processing machine, dirt substances (members) such as spatter generated during laser processing may adhere. There is. Therefore, a protective glass is provided to protect the condenser lens from the dirt member (substance) and the like, and the amount of dirt member and the like attached to the protective lens is detected (for example, Patent Document 1). reference).

Japanese translation of PCT publication No. 2001-509889

  In the configuration described in Patent Document 1, when particles such as dust adhere to the protective glass as a dirt member (substance), part of the processing laser light or measurement laser light that passes through the protective glass is irregularly reflected. In this configuration, the scattered light that has been irregularly reflected is detected by a photodetector provided on the periphery of the protective glass. However, the laser beam for measurement as well as the laser beam for processing is coaxial with the laser beam for laser processing, and when the particles are present in the region of 80% of the diameter of the protective glass, the dirt member Can be detected (see the first line at the bottom of page 6). In other words, there is a problem that when a dirt member is attached near the periphery of the protective glass, the dirt member cannot be detected.

The present invention has been made in view of the conventional problems as described above, and condenses a laser beam oscillated from a laser oscillator and irradiates the work, and in order to protect the condensing lens, A laser processing head provided with a protective glass provided on the work side of the condenser lens and a dirt detecting means for detecting dirt on the protective glass, provided around the optical axis of the laser light It is characterized by comprising detection light irradiating means for irradiating detection light entirely over the protective glass in a direction inclined with respect to the optical axis from a plurality of light sources and inward. .

  Further, in the laser processing head, the detection light irradiation means includes a ring-shaped member, and includes a plurality of point light sources on a tapered surface formed on an inner peripheral surface of the ring-shaped member. is there.

  In the laser processing head, the detection light irradiation means includes a plurality of light sources that irradiate the detection light in the radial direction on the ring-shaped support member at substantially equal intervals in the circumferential direction. Is.

  Further, in the laser processing head, a cylindrical reflection member provided on the outer peripheral surface with a reflection surface that reflects detection light emitted from each light source toward the protective glass is provided inside the ring-shaped support member. It is characterized by having.

  Further, the laser processing head is characterized in that air jetting means for forming an air curtain that blows away dirt substances in one direction is provided on the work side of the protective glass.

  In the laser processing head, a laser beam reflecting means for reflecting the laser beam condensed by the condenser lens toward the protective glass is provided between the condenser lens and the protective glass. An imaging means for imaging the laser processing position of the workpiece is provided on the opposite side of the traveling direction of the laser light reflected by the reflecting means.

  According to the present invention, the detection light from the detection light irradiation means is inclined with respect to the optical axis of the laser light, and can be applied to the protective glass. Therefore, even when the dirt is generated near the periphery of the protective glass, it can be easily detected. Therefore, the whole dirt state of protection glass can be detected, and protection glass can be exchanged appropriately.

It is a section explanatory view showing the principal part of the laser processing head concerning the embodiment of the present invention. It is perspective explanatory drawing which shows the structure of an air ejection means. It is an isometric view explanatory drawing of a ring-shaped illumination means. It is plane explanatory drawing which shows the structure of the detection light irradiation means which concerns on 2nd Embodiment. It is sectional explanatory drawing which shows the relationship between the said detection light irradiation means and protective glass.

  Referring to FIG. 1, a laser processing head 1 according to an embodiment of the present invention is supported by a head support member 3 that is movable in the X, Y, and Z axis directions, such as a robot arm. In addition, since the structure which provided the laser processing head 1 in the front-end | tip part of robot arms, such as an industrial robot, is well-known in a welding robot etc., the detail about the structure which supports the said laser processing head 1 to the said head support member 3, for example. The detailed explanation is omitted.

  The laser processing head 1 includes a lens housing 7 having a condensing lens 5 for condensing laser light oscillated from a laser oscillator (not shown), and is integrally attached to the lens housing 7. A support bracket 9 is appropriately connected to an attachment 11 that is appropriately attached to the head support member 3. In other words, the lens housing 7 is attached to the head support member 3 via the support bracket 9.

  On the one end side of the lens housing 7, a second lens housing 15 having a collimating lens 13 is integrally fixed upright. An optical fiber receiver 17 that supports the other end of the optical fiber F that is connected to the laser oscillator at one end is provided above the second lens housing 15. In other words, the collimating lens 13 converts the laser beam that tends to be emitted from the other end of the optical fiber and spreads into parallel rays.

  On one end side of the lens housing 7, there is provided a reflection mirror 18 as a laser beam reflecting means for reflecting the laser beam converted into parallel rays by the collimating lens 13 toward the condenser lens 5. A second reflection mirror 19 is provided on the other end side of the lens housing 7 to reflect the laser beam condensed by the condenser lens 5 toward the laser nozzle 21. More specifically, on the other end side of the lens housing 7, a mirror holder 23 provided with an inclined second reflection mirror 19 is mounted, and the second reflection mirror is mounted on the mirror holder 23. A refrigerant passage 25 that circulates a refrigerant such as cooling water for cooling the back surface of 19 is provided.

  The laser nozzle 21 is provided corresponding to the optical path of the laser beam reflected by the second reflecting mirror 19. More specifically, an air curtain unit 27 is mounted on the outer lower surface on the other end side of the lens housing 7. The air curtain unit 27 includes a hollow box-shaped casing 29, and the laser nozzle 21 is mounted on the lower surface of the casing 29. A protective glass 31 that protects the second reflecting mirror 19 and the condenser lens 5 is detachably mounted on the upper surface of the casing 29, and the protective glass 31 is attached to the periphery of the protective glass 31. Further, one end side of an optical fiber 33 as a dirt detecting means for detecting adhesion of a dirt member (not shown) such as a sputter is disposed. The other end of the optical fiber 33 is connected to an optical sensor (not shown).

  One end side of the casing 29 is provided with an air blowing means 35 for forming an air curtain below the protective glass 31, and an air supply path 37 such as a pipe is connected to the air blowing means 35. It is. An air discharge port 39 is formed on the other end side of the casing 29.

  The air ejection means 35 has a configuration as shown in FIG. That is, the air ejection means 35 is constituted by a cylindrical nozzle body 43 provided with air ejection ports 41A and 41B on both ends, and the air supply path 37 is provided at the center in the longitudinal direction of the nozzle body 43. A connected air supply port 45 is provided. The upper wall 43U and the lower wall 43L of the nozzle body 43 are in a closed state, and a front wall 43F that is suspended from the front end edge of the upper wall 43U in the vicinity of the upper surface of the front end edge of the lower wall 43L. Is provided. A slit 47 opened forward is formed between the lower end edge of the front wall 43F and the upper surface of the front end edge of the lower wall 43L.

  Therefore, when air is discharged and supplied from the air supply port 45 into the nozzle body 43, the air collides with the front wall 43F and is dispersed and blown out from the air outlets 41A and 41B on both ends, A part of the air is blown out in a curtain shape from the slit 47 in the forward direction. Therefore, an air curtain in a direction along the protective glass 31 is formed in the box-shaped casing 29 of the air curtain unit 27 provided with the protective glass 31 on the top. And the air which formed the said air curtain is discharged | emitted from the air discharge port 39 of the casing 29 outside.

  As already understood, when a dirt substance such as spatter scattered from the laser processing position of the workpiece passes through the laser nozzle 21 toward the protective glass 31, most of the dirt substance is ejected from the air. It is blown off by the air blown from the means 35 and is discharged to the outside from the air discharge port 39. Accordingly, it is possible to prevent the dirt substance from adhering to the protective glass 31. However, some of the dirt substance may arrive on the protective glass 31 and adhere to it. In this case, since the dirt substance is blown off downstream by the air curtain, it adheres to the peripheral edge of the protective glass 31 on the downstream side.

  By the way, when a dirt substance adheres to the vicinity of the central portion of the protective glass 31 or the like, when laser light is applied to the dirt substance when performing laser processing on the workpiece, the laser light is irregularly reflected at the dirt substance portion. . When the irregularly reflected laser light propagates through the protective glass 31 and enters one end of the optical fiber 33, it is detected by the optical sensor that a dirt substance has adhered to the protective glass 31. When the amount of dirt attached to the protective glass 31 increases and the detection value of the optical sensor becomes larger than a preset reference value, the protective glass 31 is replaced.

  In the configuration described in Patent Document 1 described above, when a dirt substance adheres within an area of 80% of the diameter of the protective glass, the dirt substance and the amount of the dirt substance can be detected. However, it was impossible to detect when a dirt substance adhered to the peripheral edge of the protective glass outside the 80% region. However, when a dirt substance adheres to the peripheral edge of the protective glass, the deterioration of the protective glass proceeds. Therefore, even when a dirt substance adheres to the peripheral edge of the protective glass, it is desired to detect the adhesion of the dirt substance. Yes.

  Therefore, in the present embodiment, the entire surface of the protective glass 31 is provided with detection light irradiation means 49 for irradiating the detection light for detecting the dirt substance. More specifically, an illumination housing 51 including the detection light irradiation means 49 is provided on the upper surface of the mirror holder 23. A ring-shaped illumination means 53 is provided in the illumination housing 51. As shown in FIG. 3, the illuminating means 53 includes a ring-shaped member 57 having a through hole 55 formed at the center thereof, and a tapered surface 57T is formed on the inner peripheral surface of the ring-shaped member 57. . The tapered surface 57T is provided with a plurality of point light sources 59 such as LEDs.

  Since each of the point light sources 59 is provided on the tapered surface 57T, the directivity directions thereof are different and are inclined with respect to the axial center of the through hole 55. The axis of the through hole 55 coincides with the axis of the laser beam for laser processing reflected by the second reflecting mirror 19 and directed in the workpiece direction. Therefore, each point light source 59 illuminates (irradiates) the protective glass 31 through the second reflecting mirror 19 from a direction inclined with respect to the optical axis of the laser beam. Therefore, the protective glass 31 is entirely irradiated by the plurality of point light sources 59. When detection light is irradiated to the dirt substance attached to the protective glass 31, the detection light is irregularly reflected in the dirt substance portion, and the detection light is propagated through the protective glass and is incident on one end of the optical fiber 33. Then, the irregularly reflected detection light is detected by the optical sensor, whereby it is detected that a dirt substance has adhered to the protective glass 31.

  When the amount of dirt attached to the protective glass 31 increases and the detection value of the optical sensor becomes larger than a preset reference value, the protective glass 31 is replaced. With the above configuration, it is possible to detect the adhesion of dirt substances over the entire surface of the protective glass 31.

  An imaging means 61 such as a CCD camera for imaging the laser processing position of the workpiece is provided on the illumination housing 51. In this case, since the illumination means 53 is ring-shaped and has a through hole 55 at the center, the imaging means 61 can pass through the through hole 55 and image the laser processing position. Accordingly, the state of the laser processing position can be imaged in a coaxial relationship with the laser beam, and the laser processing state can be observed more accurately.

  As can be understood from the above description, the detection glass 31 provided in the laser processing head is irradiated with the detection light entirely from the direction inclined with respect to the optical axis of the laser light. For example, even if a dirt substance adheres to a position where the peripheral edge is offset, it can be easily detected.

  Further, since the illumination means 53 for irradiating the protective glass 31 with detection light is configured in a ring shape having a through hole 55 at the center, the imaging means 61 such as a CCD camera is connected to the illumination means 53. It can arrange | position on the same axis | shaft and can achieve the compactization of the whole structure.

  Further, by providing the air blowing means 35 for forming the air curtain, it is possible to blow away the dirt substance that scatters and adheres to the protective glass 31 and suppresses the deterioration of the protective glass 31 due to the adhesion of the dirt substance. Thus, the service life can be extended.

  FIG. 4 shows the configuration of the detection light irradiation means according to the second embodiment. The detection light irradiation means 63 according to the second embodiment includes a ring-shaped support member 65, and a plurality of light sources 67 such as LEDs are arranged at substantially equal intervals in the circumferential direction. Is provided. Each of the light sources 67 is provided so as to be directed in the radial direction so as to irradiate the detection light in the radial direction. The directing direction of each light source 67 is not necessarily horizontal and may be directed obliquely downward.

  As shown in FIG. 5, the protective glass 31 is provided below the detection light irradiation means 63. More specifically, an annular illumination housing 69 is integrally attached to the lower portion of the lens housing 7 with a fixture such as a bolt, and the detection light irradiation means 63 is provided in the illumination housing 69. Yes.

  In order to reflect the detection light emitted from each light source 67 in the radial direction toward the protective glass 31, a cylindrical reflection integrally provided in the illumination housing 69 is provided inside the support member 65. A member 71 is provided. A tapered reflecting surface 73 having a small diameter on the lower side is formed on the outer peripheral surface of the reflecting member 71. A portion of the cylindrical reflecting member 71 below the reflecting surface 73 is formed long in the downward direction so as to be close to the protective glass 31.

  With the above-described configuration, the detection light emitted from each light source 67 in the radial direction is reflected in the direction of the protective glass 31 by the reflection surface 73 of the reflection member 71, that is, in the downward direction. Therefore, when a dirt substance is attached to the protective glass 31, the adhesion of the dirt substance can be detected.

  The protective glass 31 is detachably attached to a ring-shaped glass holder 75 detachably provided on the lower side of the lighting housing 69. Therefore, when the dirt of the protective glass 31 progresses, it can be replaced with a separate new protective glass.

DESCRIPTION OF SYMBOLS 1 Laser processing head 5 Condensing lens 7 Lens housing 13 Collimating lens 17 Optical fiber receiver 19 2nd reflective mirror 21 Laser nozzle 23 Mirror holder 27 Air curtain unit 31 Protection glass 33 Optical fiber 35 Air ejection means 39 Air discharge port 41A, 41B Air outlet 43 Nozzle body 45 Air supply port 47 Slit 49 Detection light irradiation means 53 Ring-shaped illumination means 55 Through-hole 57 Ring-shaped member 57T Tapered surface 59 Point light source (LED)
61 Imaging means

Claims (6)

A condensing lens that condenses the laser light oscillated from the laser oscillator and irradiates the work, a protective glass provided on the work side of the condensing lens to protect the condensing lens, and the protective glass A laser processing head including a contamination detection means for detecting contamination of the laser beam, wherein the head is inclined with respect to the optical axis from a plurality of light sources provided around the optical axis of the laser beam and inward A laser processing head comprising a detection light irradiation means for irradiating the protective glass with detection light over the entire surface.   2. The laser processing head according to claim 1, wherein the detection light irradiation means includes a ring-shaped member, and includes a plurality of point light sources on a tapered surface formed on an inner peripheral surface of the ring-shaped member. Laser processing head.   2. The laser processing head according to claim 1, wherein the detection light irradiation means includes a plurality of light sources that irradiate detection light in an inward direction at substantially equal intervals in a circumferential direction on a ring-shaped support member. Laser processing head.   4. The laser processing head according to claim 3, wherein the outer peripheral surface includes a reflection surface that reflects detection light emitted from each of the light sources toward the protective glass inside the ring-shaped support member. A laser processing head comprising a reflecting member.   The laser processing head according to any one of claims 1 to 4, further comprising an air blowing means for forming an air curtain for blowing a dirt substance in one direction on the workpiece side of the protective glass. Laser processing head.   6. The laser beam according to claim 1, wherein the laser beam condensed by the condenser lens is reflected toward the protective glass between the condenser lens and the protective glass. A laser processing head comprising: a reflection unit; and an imaging unit that images a laser processing position of a workpiece on a side opposite to a traveling direction of the laser beam reflected by the laser beam reflection unit.

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