JP6385119B2 - Protection glass contamination prevention method and laser processing head - Google Patents

Description

  The present invention relates to a protective glass contamination prevention method and a laser processing head for preventing fume generated during laser processing from adhering to protective glass provided in a laser processing head. In more detail, in forming the rectification of the protective gas from the periphery of the protective glass toward the center along one side of the protective glass to prevent fumes generated by laser processing from contacting the protective glass, The present invention relates to a contamination prevention method and a laser processing head for preventing a fume from adhering to a protective glass by giving a restriction to the outflow passage of the protective gas so as to make the flow faster.

  A laser processing head in a laser processing machine is provided with a condensing lens, and the condensing lens may be contaminated by fumes and spatter generated during laser processing of a workpiece. Therefore, in order to protect the condenser lens and prevent contamination, a protective glass is provided in the laser processing head. In the above configuration, the protective glass can be protected by the protective glass, but the protective glass is contaminated. Therefore, in order to prevent fumes and sputters generated during laser processing from adhering to the protective glass, a configuration in which the fumes and spatters are blown away by high-speed air is employed (for example, see Patent Documents 1 and 2).

JP 2000-263276 A JP 2007-21505 A

  In the configuration described in Patent Document 1, high-speed air is jetted from the air blowing nozzle along the lower surface of the protective glass provided in the laser processing head, and fumes and spatter generated during laser processing are blown away by the high-speed air. Is. Since the high-speed air ejected from the air blowing nozzle is turbulent, the fumes are involved and blown away. However, due to the turbulent flow, some of the entrained fumes may come into contact with the protective glass. Therefore, the downstream side of the protective glass against high-speed air may be contaminated.

  In addition, when the flow of high-speed air is changed to a flow of rectification that does not involve fume, it is difficult to protect the protective glass from spatter, because it is not possible to obtain a flow velocity that blows away spatter scattered at high speed from the laser processing position. There is a problem.

  The configuration described in the cited document 2 injects the first air blow from the lower outer periphery of the protective glass, and injects the second air blow along the nozzle inner peripheral surface provided below the protective glass. The second air blow attempts to converge after passing through the nozzle opening.

  In the above configuration, if the first and second air blows flow without becoming a turbulent flow, it is difficult to remove the spatter scattered at a high speed. Moreover, in the said structure, since a 1st air blow is injected from diagonally downward with respect to protective glass, and is converted into the flow of a downward direction after that, a 1st air blow of the inside of a nozzle is carried out. There is a tendency for the flow to return to the blowout part and for the turbulent flow.

  Therefore, there is a problem that a part of the fumes generated during the laser processing is caught in the turbulent flow and may adhere to the lower surface of the protective glass.

The present invention has been made in view of the above-described problems, and includes a protective glass for protecting the condenser lens on the lower side of the condenser lens in the laser processing head, and along the lower surface of the protective glass. A protective glass contamination preventing method for preventing fume from adhering to the protective glass in a laser processing head provided with a gas flow forming means for supplying protective gas, which is from a swirl flow path provided under the protective glass . In order to rectify the swirl flow, rectification in the center direction is formed through the protective gas rectifying means provided in contact with the lower surface of the protective glass , and a central hole is provided on the lower side of the protective glass. A fume aperture is provided to restrict the outflow path of the protective gas, thereby preventing the protective gas from flowing out of the central hole at a higher speed and adhering to the protective glass. The one in which the features.

Also, a laser processing head comprising a protective glass for protecting the condensing lens below the condensing lens in the laser processing head, and gas flow forming means for flowing a protective gas along the lower surface of the protective glass A protective gas rectifying means for rectifying a swirling flow flowing in a central direction from a swirling flow path provided on the lower side of the protective glass, and in contact with the lower surface of the protective glass, the lower side of the protective glass In addition, a fume aperture having a central hole for restricting the outflow passage of the protective gas is provided.

  In the laser processing head, an upward or downward cylindrical portion is provided on at least one of the upper surface and the lower surface of the fume aperture.

  In the laser processing head, the fume aperture is provided integrally with a protective glass support member that supports the protective glass.

  In the laser processing head, the gas flow forming means includes a cylindrical porous member in order to rectify the protective gas flowing from the periphery toward the center.

  According to the present invention, a fume aperture having a central hole is disposed below the protective glass, a restriction is applied to the flow path through which the protective gas flows, and the protective gas flows out of the central hole at a higher speed. Is. Therefore, it can prevent that a fume contacts and adheres with respect to protective glass.

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 explanatory drawing which shows the various forms of a fume aperture.

  Hereinafter, the configuration of a laser processing head according to an embodiment of the present invention will be described with reference to the drawings. As conceptually and schematically shown in FIG. 1, the laser processing head 1 is a robot hand in an industrial robot, for example. And a head housing 3 that is movable in the X, Y, and Z axis directions. A condensing lens 5 for condensing the laser beam LB oscillated by the laser oscillator is provided in the head housing 3.

  At the front end side (lower side in FIG. 1) of the head housing 3, a machining head main body 7 having a through hole 7H through which the laser beam LB can pass is provided at the center via a fixture (not shown) such as a bolt. It is detachably attached. An air supply block 9 is detachably attached to the front end side of the processing head main body 7 via an appropriate attachment. A laser nozzle 11 is detachably attached to the leading end side of the air supply block 9.

  The front end surface of the processing head body 7, that is, the attachment surface (mounting surface) to which the air supply block 9 is attached, is provided with an engagement recess 13 that opens the air supply block 9 side and one side surface side. A protective glass holder 17 having a protective glass 15 is detachably provided in the engaging recess 13. The protective glass holder 17 is formed in the shape of a thick block, and the outer shape when viewed in plan is formed in a quadrangular shape. On one side surface of the protective glass holder 17, a grip portion 19 for attaching / detaching the protective glass 17 to / from the engaging recess 13 is provided.

  As already understood, the protective glass holder 17 is supported by the air supply block 9 when arranged in the engagement recess 13. Therefore, the air supply block 9 has a function of supporting the protective glass 15 and can also be called a kind of protective glass support member.

  On the upper surface of the protective glass holder 17, an annular protective glass holding portion 21 having the protective glass 15 detachably formed is formed. And in order to fix the said protective glass 15, in the said protective glass holding | maintenance part 21, the cyclic | annular glass presser 23 comprised from appropriate members, such as an O ring and a snap ring, is provided, for example. Below the protective glass 15, gas flow forming means for flowing a protective gas along the lower surface of the protective glass 15 is provided. That is, an annular swirl passage 25 in which a protective gas can swirl is formed at a position below the protective glass holder 17 and corresponding to the lower surface of the protective glass 15.

  The protective gas serves to prevent the protective glass 15 from being contaminated by fumes generated during laser processing. In other words, the protective gas serves to protect the protective glass 15 from fumes. An annular protrusion that protrudes toward the protective glass 15 is provided on the inner peripheral edge of the swirl passage 25, and the outer periphery of the annular protrusion flows from the swirl passage 25 toward the center. A protective gas rectifying means 29 for rectifying the protective gas is provided.

  The protective gas rectifying means 29 is formed, for example, by forming a metal mesh with a small mesh in a double cylindrical shape, and the upper edge of the protective gas rectifying means 29 is in contact with the lower surface that is one side surface of the protective glass 15. They are in close contact. The configuration of the protective gas rectifying means 29 is not limited to a wire mesh, and is a structure in which a porous member (including a wire mesh) such as a sponge, a sintered metal, a sintered resin, and glass wool is formed in an annular shape. It may be.

  With the above configuration, the flow of the protective gas from the swirling flow path 25 through the protective gas rectifier 29 toward the center is rectified into a linear flow. At this time, the flow of the linear protective gas is formed in a double (multi-layer) flow corresponding to the vertical width of the protective gas rectifying means 29.

  A through hole 9H through which the laser beam LB can pass is formed at the center of the air supply block 9. An annular (circular) swirl flow generating flow path 31 having substantially the same diameter as the swirl flow path 25 is located at a position corresponding to the swirl flow path 25 provided on the protective glass holder 17 on the upper surface. Is formed. In order to generate a swirl flow of the protective gas in the swirl flow generating flow path 31, an air supply path 33 connected to an air supply source (not shown) as a protective gas supply source is connected in a tangential direction. Therefore, the air supplied from the air supply path 33 into the swirl flow generation flow path 31 becomes a swirl flow.

  In order to guide the swirl flow of the air generated in the swirl flow generation flow path 31 to the swirl flow path 25, a plurality of locations at the bottom of the swirl flow path 25 communicated with the swirl flow generation flow path 31. An arc-shaped long hole 34 is formed along the swirling flow path 25. Therefore, when a swirl flow is generated by supplying air into the swirl flow generation flow path 31, the swirl flow of air is moved from the long hole 34 into the swirl flow path 25.

  At the tip of the air supply block 9, that is, at a position away from the protective glass 15, a protective gas (air) is applied at high speed in a direction perpendicular to the axis of the laser processing head 1, that is, the axis of the laser beam LB A high-speed jet port 35 for jetting is provided. The opening of the high-speed jet port 35 is formed as a flat opening in a direction orthogonal to the axis of the laser beam LB. Therefore, the air jetted from the high-speed jet port 35 forms a flat high-speed air curtain that is orthogonal to the axis of the laser beam LB.

  An outside air suction port 37 for attracting a large amount of outside air by being attracted by a high speed flow of air ejected from the high speed outlet 35 is formed at a position close to the high speed outlet 35 and below. is there. The air supply block 9 is provided with a large air discharge port 39 so as to face the high-speed jet port 35. Therefore, when air is ejected from the high-speed jet port 35 at a high speed, it is attracted by this high-speed air flow, and a large amount of outside air is sucked from the outside air suction port 37 and discharged from the air discharge port 39 at the opposite position to the outside. Will be.

  Therefore, the spatter and fumes scattered from the laser processing position and entering the laser processing head 1 are exposed to the outside by the high-speed flow of air ejected from the high-speed ejection port 35 and a large amount of outside air sucked from the outside air suction port 37. Will be discharged. The high-speed jet 35 is separated as appropriate so that the high-speed flow of air jetted from the high-speed jet 35 does not disturb the rectification of the protective gas flowing along the lower surface of the protective glass 15. It is provided at the position.

  Further, a fume aperture 41 is provided in order to prevent spatter and fumes scattered from the laser processing position from contacting and adhering to the protective glass 15. The fume aperture 41 is an upper side in the through hole 9 in the air supply block (protective glass support member) 9, and the protective glass 15 in the engagement recess 13 and the air supply block 9 are provided in the air supply block 9. It is provided between the air discharge port 39. The fume aperture 41 is formed in a disc shape having a central hole 43 at the center.

  As described above, a chamber 45 is formed between the protective glass 15 and the fume aperture 41 by the configuration in which the fume aperture 41 is arranged on the upper side in the through hole 9 in the air supply block 9. . The outlet of the chamber 45 is the central hole 43 and is narrowed to a small diameter.

  In the above configuration, when laser processing is performed by irradiating the workpiece W with the laser beam LB collected by the condenser lens 5, fumes are generated from the laser processing position and spatter is scattered. Most of the fumes and spatter generated during the laser processing are discharged from the air discharge port 39 to the outside by the high-speed flow of air discharged from the high-speed discharge port 35 and a large amount of outside air sucked from the outside air suction port 37. become. However, a very small part of fumes and the like tends to enter the laser processing head 1 and contaminate the protective glass 15.

  That is, since the high-speed flow of the air ejected from the high-speed jet port 35 is a turbulent flow, a part of the fumes may flow toward the protective glass 15. However, a fume aperture 41 having a central hole 43 is disposed below the protective glass 15, and a chamber 45 is formed between the protective glass 15 and the fume aperture 41. Therefore, the fumes that tend to flow in the direction of the protective glass 15 enter a passage narrowed by the central hole 43 of the fume aperture 41, and the flow of fumes in the direction of the protective glass 15 is suppressed. .

  In addition, a chamber 45 is formed between the protective glass 15 and the fume aperture 41, and the protective gas flowing along the lower surface of the protective glass 15 flows downward from the central hole 43 from the chamber 45. It will be leaked. Accordingly, the protective gas in the chamber 45 is throttled by the central hole 43 and flows out at a higher speed. In other words, the central hole 43 serves to restrict the outflow path of the protective gas flowing out from the chamber 45 and suppresses the entry of fume, outside air, etc. into the chamber 45 from the outside. is there.

  In addition, a swirl passage 25 is provided below the protective glass 15 so that air as protective gas rotates and a plurality of air rectified by the protective gas rectifying means 29 from the swirl passage 25. It forms a linear flow of layers and flows toward the center. Accordingly, when a very small amount of fume enters the chamber 45 from the central hole 43 of the fume aperture 41, the fume adjacent to the lower surface of the protective glass 15 is caused to flow toward the center by the protective gas, In this part, it flows downward and flows out from the central hole 43 to the outside. Therefore, the fumes are prevented from coming into contact with the lower surface of the protective glass 15.

  By the way, since the air is rotating (swirling) in the swirling flow path 25, the flow velocity and the pressure distribution are uniformly maintained in any position in the circumferential direction in the swirling flow path 25. . Therefore, the flow velocity distribution of the air flow that passes through the protective gas rectifying means 29 and is rectified as a flow in the central direction becomes uniform. In other words, the flow velocity and flow rate in the flow in the center direction rectified by the protective gas rectifying means 29 are uniform, and it is possible to prevent the occurrence of turbulent flow due to the flow velocity difference and the like, and no outside air is involved. Is. Therefore, the fume adjacent to the lower surface of the protective glass 15 is not involved, and a part of the fume can be prevented from adhering to the lower surface of the protective glass 15.

  As can be understood from the above description, according to the present embodiment, the fume aperture 41 having the central hole 43 having a drawing function is disposed below the protective glass 15, and the protective glass 15 and the fume aperture 41 are arranged. Therefore, the fume can be effectively prevented from entering the chamber 45 and the fume can be prevented from adhering to the protective glass 15.

  By the way, the present invention is not limited to the above-described embodiments, and can be implemented in other forms by making appropriate changes. For example, as shown in FIGS. 2A, 2 </ b> B, and 2 </ b> C, an upward or downward cylindrical portion 47 is provided on at least one of the upper and lower surfaces of the fume aperture 41. Is also possible. According to the above configuration, for example, when the spatter tends to enter the chamber 45 by being scattered in a direction intersecting the optical axis of the laser beam LB, or along the lower surface of the fume aperture 41, for example, the central hole 43 When fume tends to flow into the chamber 45 by flowing in the direction, it is possible to effectively prevent spatter and fume from entering the chamber 45.

  Moreover, in the said description, it demonstrated that the air supply block (protective glass support member) 9 and the fume aperture 41 were provided separately. However, the air supply block 9 and the fume aperture 41 can be provided integrally.

  Furthermore, the central hole 43 in the fume aperture 41 may be configured to be unevenly distributed on the upstream side of the air ejected from the high-speed ejection port 35 with respect to the optical axis of the laser beam LB. According to this configuration, it is possible to effectively prevent spatter and the like blown away by air from entering the chamber 45.

DESCRIPTION OF SYMBOLS 1 Laser processing head 5 Condensing lens 9 Air supply block 11 Laser nozzle 13 Engagement recessed part 15 Protective glass 17 Protective glass holder 29 Protective gas rectification means 31 Swirl flow generation flow path 35 High-speed jet port 37 Outside air suction port 39 Air exhaust port 41 Hume aperture 43 Center hole 45 Chamber 47 Tube

Claims (5)

In the laser processing head comprising a protective glass for protecting the condensing lens on the lower side of the condensing lens in the laser processing head, and gas flow forming means for flowing a protective gas along the lower surface of the protective glass. A protective glass contamination prevention method for preventing fume from adhering to the protective glass, and in order to rectify the swirl flow from the swirl flow path provided on the lower side of the protective glass, it contacts the lower surface of the protective glass. The protective gas rectifying means is provided to form a rectification in the central direction, and a fume aperture having a central hole is disposed under the protective glass to restrict the outflow passage of the protective gas. A protective glass contamination prevention method characterized in that the protective gas is flown out of the central hole at a higher speed to prevent fume from adhering to the protective glass. The laser processing head includes a protective glass for protecting the condensing lens below the condensing lens in the laser processing head, and gas flow forming means for flowing a protective gas along the lower surface of the protective glass. A protective gas rectifying means for rectifying the swirling flow flowing in the center direction from the swirling flow path provided on the lower side of the protective glass, and in contact with the lower surface of the protective glass, on the lower side of the protective glass, A laser processing head comprising a fume aperture having a central hole for constricting the outflow passage of the protective gas.   The laser processing head includes a protective glass for protecting the condensing lens below the condensing lens in the laser processing head, and gas flow forming means for flowing a protective gas along the lower surface of the protective glass. A fume aperture having a central hole for constricting the outflow passage of the protective gas on the lower side of the protective glass, and an upward or downward tube on at least one of the upper surface and the lower surface of the fume aperture. A laser processing head comprising a shape portion.   4. The laser processing head according to claim 2, wherein the fume aperture is provided integrally with a protective glass support member that supports the protective glass.   5. The laser processing head according to claim 2, wherein the gas flow forming means includes a cylindrical porous member to rectify the protective gas flowing from the periphery toward the center. A featured laser processing head.

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