JP2018001180A - Laser processing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing head including cross jet forming means which blows out sputter or the like scattering in a protection glass direction.SOLUTION: A laser processing head internally includes a condensing lens for condensing a laser beam oscillated from a laser oscillator, includes a nozzle 5 on a tip end part, and internally includes a protection glass 7 for protecting the condensing lens. The laser processing head includes cross jet forming means 19 which forms a cross jet in a direction intersecting an optical axis of the laser beam between the protection glass 7 and the nozzle 5 so as to discharge sputter intruding in an inside of the nozzle 5 from a laser processing position of a workpiece. A vertical clearance dimension of a cross jet inflow opening part 41 on an upper side is smaller than a vertical clearance dimension of a cross jet inflow opening part 43 on a lower side formed in the cross jet forming means 19.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser processing head having a condensing lens for condensing laser light oscillated from a laser oscillator, a nozzle at the tip, and a protective glass for protecting the condensing lens. . More specifically, the present invention relates to a laser processing head provided with a cross jet forming means for forming a cross jet that blows off a sputter that has entered the nozzle from a laser processing position of a workpiece in a direction crossing the laser beam.

  The laser beam oscillated from the laser oscillator is condensed by a condensing lens provided in the laser processing head and irradiated onto the workpiece. As described above, when laser processing is performed on the workpiece by irradiating the workpiece with the laser beam, the spatter may scatter from the laser processing position and enter the laser processing head. When spatter adheres to and contaminates the protective glass provided in the laser processing head, the protective glass may be heated and damaged. In view of this, it has been proposed to generate a cross jet, which is a high-speed flow of air, in the laser processing head and to discharge the sputters that have entered the outside by the cross jet (see, for example, Patent Document 1).

JP 2014-200247 A

  The configuration described in Patent Document 1 includes a cross jet forming unit that forms a cross jet that blows off spatter that has entered the inside from the nozzle between the protective glass provided in the laser processing head and the nozzle. It is. The cross jet forming means includes a cross jet nozzle on the ceiling wall of the upper and lower two-stage cross jet passages.

  Then, by injecting cross jet gas from the cross jet nozzle, a secondary flow for sucking outside air from the inlet side of the cross jet passage is generated. An air curtain is formed by this secondary flow, and the air curtain is configured to blow away the spatter that has scattered and entered from the nozzle into the laser processing head.

  According to the above configuration, although spatter that has scattered from the laser processing position can be blown to the outside, sometimes spatter may adhere to the protective glass, and further improvement has been desired.

  The present invention has been made in view of the above-described problems, and includes a condensing lens for condensing laser light oscillated from a laser oscillator and a nozzle at the tip, and protects the condensing lens. A laser processing head provided with a protective glass inside, the laser beam between the protective glass and the nozzle in order to discharge spatter that has entered the nozzle from the laser processing position of the workpiece to the outside A cross jet forming means for forming a cross jet in a direction intersecting with the optical axis of the cross jet, and a cross above an upper and lower interval dimension of a lower cross jet inflow opening provided in the cross jet forming means. The vertical distance between the jet inflow openings is small.

  In the laser processing head, the upper and lower cross jet inflow openings have the same width, and the upper and lower cross jet inflow openings have a vertical distance of 1/9 of the vertical distance of the lower cross jet inflow openings. ~ 8/9, preferably 3/9.

  Further, in the laser processing head, in the cross jet forming means, the upper surface of the nozzle plate for forming a flow of flat high-speed air is formed in a planar flow path regulated in three directions by a rising surface, The rising surface in the direction along the flow of the high-speed air is formed parallel to the flow direction of the high-speed air.

  In the laser processing head, the cross-sectional shape of the high-speed air outlet for the planar flow path of the nozzle plate is an elongated hole, and the longitudinal dimension of the outlet is the interval between the parallel rising surfaces. And the width dimension in the direction perpendicular to the longitudinal direction is about ½ of the planar flow path of the nozzle plate.

  Further, in the laser processing head, a ring-shaped aperture is provided on an upper portion of the opening block provided with the cross jet forming means at a lower portion, and the inner surface of the aperture is opposed to a semicircular inner surface provided in the opening block. The peripheral surface is provided in a state protruding inward.

  According to the present invention, the wind speed of the cross jet can be increased, and the spatter that has entered the laser processing head can be effectively discharged to the outside.

It is a section explanatory view of a laser processing head concerning an embodiment of the present invention. It is a section explanatory view of the principal part concerning the embodiment of the present invention. It is a perspective explanatory view showing an opening block, a buffer plate, and a nozzle plate. It is a top view of a buffer plate. It is a top view of a nozzle plate. It is a graph which shows the relationship between the clearance gap of the inflow opening part in a 1st flow path and a 2nd flow path, and the relationship of a wind speed.

  Hereinafter, a laser processing head 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the laser processing head 1 in a cross-sectional state. The laser processing head 1 includes a processing head main body 3, and a condensing lens (not illustrated) that condenses laser light oscillated from a laser oscillator (not illustrated) is provided in the processing head main body 3. Yes. And the nozzle 5 is provided in the front-end | tip part of the said processing head main body 3 so that attachment or detachment is possible.

  Then, in the processing head main body 3, the condensing lens is formed between the condensing lens and the nozzle 5 from spatter that has entered the laser processing head 1 through the nozzle 5 from the laser processing position. A protective glass 7 for protection is provided. More specifically, the machining head main body 3 includes an opening block 9 (including an opening portion 9A having a large opening in one side direction (for example, the direction opposite to the laser machining progress direction) as well as the vertical direction. 3).

  That is, as shown in FIG. 3, the opening block 9 has a shape opened in three directions, that is, the vertical direction and the one side direction. A portion where the laser beam is transmitted downward is formed in a semicircular hole 9B, and the opposite side wall surface 9C of the opening 9A is connected to the hole 9B. An aperture holder 11 is attached to the upper surface of the opening block 9. The aperture holder 11 is provided with the protective glass 7 through a glass holder 13 so as to be detachable and replaceable.

  A through-hole 15 through which laser light can pass is formed in the vertical direction in the center of the aperture holder 11, and a ring-shaped aperture 17 is provided in the through-hole 15. The center position of the aperture 17 is provided to coincide with the axis of the semicircular hole 9B. The radius of the aperture 17 is smaller than the radius of the hole 9B.

  Therefore, the inner peripheral surface 17A of the aperture 17 is provided in a state of protruding inward with respect to the semicircular inner surface 9F of the hole 9B, as shown in FIG. Therefore, when a part of fumes and spatters tends to rise along the inner surface 9F of the hole 9B, the fume and spatter adhesion to the protective glass 7 can be effectively suppressed. In addition, the aperture 17 functions to reduce spatter that directly scatters from the laser processing position of the workpiece onto the protective glass 7. Accordingly, it is possible to effectively suppress the adhesion of spatter to the protective glass 7.

  Below the opening block 9, the opening 9 </ b> A is opposed to the optical axis of the laser beam, in other words, in a direction intersecting (orthogonal to) the axis of the hole 9 </ b> B. Cross jet forming means 19 for forming a cross jet (flow of high-speed air) is provided. The overall configuration of the cross jet forming means 19 is similar to the cross jet forming means described in Patent Document 1. However, the configuration of the main part is different.

  More specifically, a fluid passage 21 similar to the configuration described in Patent Document 1 is formed in the front wall portion 9D of the opening block 9. The fluid passage 21 has a nozzle hole 23 communicating with the end face of the front wall 9D. The cross-sectional shape of the nozzle hole 23 is formed in a circular shape due to processing problems. A buffer plate 25 is provided on the end surface of the front wall portion 9D of the opening block 9 via a mounting screw or the like.

  The buffer plate 25 has a function of forming an air flow having a circular cross-section ejected from the nozzle hole 23 into a uniform flow as a whole. As shown in FIG. The chamber 25 </ b> A communicated with 23 is formed in a space having a rectangular cross section (long hole shape). By the way, when the space corresponding to the chamber 25A is provided on the lower surface of the front wall portion 9D in the opening block 9, the buffer plate 25 can be omitted.

  The lower surface of the buffer plate 25 is in close contact with the nozzle plate 27 that is ejected rightward in FIG. 2 by using the air ejected from the nozzle hole 23 and ejected through the chamber 25A as a flat cross jet. Is provided. The size of the nozzle plate 27 is substantially the same as the size of the buffer plate 25. On the upper surface of the nozzle plate 27, there is provided a flat channel 29 whose three directions are regulated by rising surfaces 31A, 31B and 31C in order to form a flat high-speed air flow.

  More specifically, the rising surfaces 31A and 31C located on both sides of the cross jet flow direction (the direction of arrow A shown in FIGS. 2 and 5) are formed in parallel to the cross jet flow direction. The distance LA between the compatible ascending surfaces 31A and 31C is formed substantially equal to the dimension LB in the longitudinal direction of the chamber 25A. The rising surface 31B on the end side of the nozzle plate 27 substantially coincides with one inner edge 25B of the buffer plate 25 in the longitudinal direction of the chamber 25A.

  The width dimension from the rising surface 31B to the opening edge 31D in the nozzle plate 27 is formed to be about twice the width dimension W in the direction orthogonal to the longitudinal direction in the chamber 25A. In other words, about ½ of the outlet side (upper side in FIG. 5) of the planar flow path 29 is in a state where the vertical interval of the opening is narrowed by the buffer plate 25. Accordingly, the cross jet outlet 33 at the opening edge 31 </ b> D of the nozzle plate 27 has a rectangular shape regulated by the bottom surface of the planar flow path 29, the rising surfaces 31 </ b> A and 31 </ b> C on both sides, and the buffer plate 25. The vertical opening dimension of the cross jet outlet 33 is equal to the height dimension of the rising surfaces 31A and 31C and is 1 mm or less.

  Below the cross jet forming means 19, a first flow path plate 37 having a through hole 35 through which laser light can pass downward is provided at an appropriate distance from the nozzle plate 27. Yes. A second flow path plate 39 is provided below the first flow path plate 37 with an appropriate interval. A first flow path 41 is formed between the nozzle plate 27 and the first flow path plate 37. A second flow path 43 is formed between the first flow path plate 37 and the second flow path plate 39.

  The first and second flow paths 41 and 43 are vertically separated with the first flow path plate 37 therebetween. And the 1st, 2nd flow paths 41 and 43 have an inlet opening part on the opposite side to the flow direction (the arrow A direction) of the cross jet. At positions corresponding to the opening portions of the first and second flow paths 41 and 43, a guide plate 45 for sucking outside air is disposed so as to be directed upward. And the exhaust plate 45 is arrange | positioned at the discharge port of the other side. In the above configuration, the vertical spacing dimension of the cross jet inflow opening in the upper flow path 41 is larger than the vertical spacing dimension of the cross jet inflow opening in the lower flow path 43 as shown in FIG. It is small.

  A nozzle holder 47 including the nozzle 5 is provided below the second flow path plate 39.

  In the above configuration, when laser processing is performed by irradiating the workpiece with laser light, a part of fumes and spatter generated at the laser processing position may enter the laser processing head 3 and adhere to the protective glass 7. is there. Therefore, high-pressure air is ejected from the nozzle hole 23, and high-speed air is ejected in a flat shape in the cross jet forming means 19 to blow off spatter and the like. As described above, when high-speed air is ejected in the cross jet forming means 19, a negative pressure is generated and a large amount of outside air is sucked into the first and second flow paths 41 and 43, and spatter and the like are blown off by this outside air. It is what

  By the way, in a structure like the said patent document 1, it is the structure which injects high pressure air from the nozzle hole 23 which is a round hole to the nozzle plate 27, and also in the upper and lower 1st, 2nd flow paths 41 and 43. Since the distance between the openings was substantially equal, the effect of sucking outside air was small, and the effect of blowing off spatter and the like was small.

  Therefore, in order to effectively suck out the outside air and effectively blow off the spatter and the like, various experiments were performed, and the vertical distance between the openings in the upper first flow path 41 was set to the lower second flow path. It has been found that the flow velocity of the cross jet ejected from the cross jet forming means 19 increases when the distance is smaller than the vertical distance of the opening at 43.

  That is, the vertical distance between the openings in the upper first flow path 41 and the vertical distance between the openings in the lower second flow path 43 are variously changed and arranged at a predetermined position on the downstream side of the cross jet forming means 19. When the wind speed was measured according to the wind speed shape, the result shown in FIG. 6 was obtained.

  As is clear from FIG. 6, when the clearance of the opening in the lower second flow path 43 is set to 0, the wind speed is 25 m / s or less even if the clearance of the upper first flow path 41 changes. . Also from this result, it is necessary to provide the lower second flow path 43 and the upper flow path 41. And while changing the clearance gap of the opening part in the lower 2nd flow path 43 to 3 mm, 6 mm, and 9 mm and adjusting the clearance gap of the opening part in the upper 1st flow path 41 to 0 mm-8 mm, a lower opening part When the gap is 9 mm and the upper opening is 3 mm, the wind speed is 29 m / s or more, which is desirable. As is clear from FIG. 6, the relationship between the gaps of the openings in the upper and lower flow paths 41 and 43 is preferably 1/9 to 8/9, and more preferably 3/9.

  By the way, in the said structure, the cross jet formation means 19 is equipped with the buffer plate 25, and this buffer plate 25 is equipped with the chamber 25A. Therefore, the high-pressure air ejected from the nozzle hole 23 is supplied as an even pressure distribution to the planar flow path 29 in the chamber 25A. Therefore, the speed distribution of the cross jet ejected in a flat shape from the cross jet forming means 19 becomes substantially equal as a whole, and the spatter and fumes scattered in the direction of the protective glass 7 can be effectively blown off.

  As can be understood from the above description, according to the present embodiment, the cross jet forming means 19 is provided with the buffer plate 25 in which the chamber 25A is formed. The opening gap in the upper first flow path 41 for sucking outside air is made smaller than the opening gap in the lower second flow path 43. Accordingly, the cross jet ejected from the cross jet forming means 19 can be held at high speed, and the spatter and the like scattered in the direction of the protective glass 7 in the laser processing head can be effectively blown off.

DESCRIPTION OF SYMBOLS 1 Laser processing head 3 Processing head main body 5 Nozzle 7 Protection glass 9 Opening block 11 Aperture holder 17 Aperture 19 Cross jet formation means 23 Nozzle hole 25 Buffer plate 25A Chamber 27 Nozzle plate 29 Planar flow path 31A, 31B, 31C Rise surface 31D Opening Edge 33 Cross jet outlet 37 First flow path plate 39 Second flow path plate 41 First flow path 43 Second flow path

Claims (5)

  A laser processing head comprising a condensing lens for condensing laser light oscillated from a laser oscillator, a nozzle at the tip, and a protective glass for protecting the condensing lens, A cross jet is formed between the protective glass and the nozzle in a direction intersecting the optical axis of the laser beam in order to discharge the spatter that has entered the nozzle from the laser processing position of the laser. And a cross-jet inflow opening on the upper side of the lower cross-jet inflow opening provided in the cross-jet forming means having a vertical space smaller than that of the lower cross-jet inflow opening. Processing head.   2. The laser processing head according to claim 1, wherein the width of the upper and lower cross jet inflow openings is equal, and the upper and lower cross dimension of the upper cross jet inflow opening is equal to the vertical distance of the lower cross jet inflow opening. 1/9 to 8/9, preferably 3/9.   3. The laser processing head according to claim 1, wherein, in the cross jet forming means, the upper surface of the nozzle plate for forming a flow of flat high-speed air is a flat flow path regulated in three directions by a rising surface. A laser processing head, wherein the rising surface in the direction along the flow of the high-speed air is formed in parallel with the flow direction of the high-speed air.   4. The laser processing head according to claim 3, wherein a cross-sectional shape of a high-speed air blowing port with respect to the planar flow path of the nozzle plate is a long hole, and a dimension in a longitudinal direction of the blowing port is equal to the parallel rising. A laser processing head characterized in that a width dimension in a direction substantially equal to a surface interval and perpendicular to a longitudinal direction is about ½ of the planar flow path of the nozzle plate.   5. The laser processing head according to claim 1, wherein a ring-shaped aperture is provided on an upper part of the opening block provided with the cross jet forming means at a lower part, and a semicircular inner surface provided on the opening block. On the other hand, the laser processing head is characterized in that the inner peripheral surface of the aperture is provided in a state of protruding inward.

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