Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/08—Devices involving relative movement between laser beam and workpiece
  • B23K26/0869—Devices involving movement of the laser head in at least one axial direction
  • B23K26/0876—Devices involving movement of the laser head in at least one axial direction in at least two axial directions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
  • B23K26/1462—Nozzles; Features related to nozzles
  • B23K26/1464—Supply to, or discharge from, nozzles of media, e.g. gas, powder, wire
  • B23K26/1476—Features inside the nozzle for feeding the fluid stream through the nozzle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
  • B23K26/1462—Nozzles; Features related to nozzles
  • B23K26/1488—Means for protecting nozzles, e.g. the tip surface
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
  • B23K26/36—Removing material
  • B23K26/38—Removing material by boring or cutting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/02—Iron or ferrous alloys
  • B23K2103/04—Steel or steel alloys
  • B23K2103/05—Stainless steel

Definitions

• the invention relates to a laser nozzle that can be used in laser-beam cutting with an internal movable element comprising a skirt for concentrating the cutting gas in the cutting groove and also offering an industrial implementation as well as a duration improved lives.
• Laser beam cutting requires the use of a generally copper nozzle having the effect of channeling the gas and passing the laser beam.
• the nozzles typically have diameters of their outlet orifice of between 0.5 and 3 mm for a working distance of between 0.6 and 2 mm.
• US-A-4,031,351 discloses a laser cutting nozzle comprising a movable member whose end is pressed by a spring against the surface of the workpiece to promote the injection of the cutting gas into the groove.
• the major disadvantage of this solution lies in the fact that the force exerted by the spring in the direction of the sheet, accumulated at the pressure of the cutting gas, causes the movable member to exert a major force on the sheet to be cut. It follows a risk of deformation, scratching or even driving the sheet, which is usually simply placed on the table of the industrial cutting machine.
• this nozzle comprises an elastic member exerting an elastic restoring force on the movable member in a direction tending to move away from the sheet.
• Shocks produced at the end of the skirt can cause untimely emergency stops of the machine. These shocks may also damage and impair the effectiveness of the skirt, until it causes its breakage or complete deterioration. It is then necessary to replace the movable element of the nozzle, which causes an increase in production costs and a decrease in productivity of the industrial cutting machine.
• JP-A-7251287 a laser nozzle comprising a movable member and a spring exerting a force tending to press said element on the sheet.
• this nozzle uses the force exerted by the cutting gas escaping below the surface of said element located opposite the sheet to cut to cause a small distance from the movable element relative to the sheet.
• JP-A-7251287 does not allow a distance of the movable element relative to the sheet and we are faced with the problems mentioned above, the movable element permanently protruding to the outside the nozzle body. This is also a problem in the drilling phases, too close proximity of the nozzle with the sheet being avoided due to the large projections of molten metal generated.
• the problem that arises is therefore to propose a laser beam cutting nozzle for which the abovementioned problems are greatly reduced, or even eliminated, in particular a laser nozzle whose displacement on the cut sheet metal is much less disturbed in the event of obstacles. lying on the surface of said sheet and for which the shocks resulting from the meeting of the nozzle with said obstacles are greatly reduced compared to existing solutions.
• the laser nozzle of the present invention must be able to be implemented industrially, have improved robustness and life compared to existing solutions, and not disrupt the operation of the cutting machine on which said nozzle is installed.
• the solution of the present invention is then a laser nozzle comprising:
• a nozzle body comprising an axial housing and a first outlet located at the front face of the nozzle body;
• a movable element arranged in the axial housing of the nozzle body, comprising a front part forming a skirt and comprising a second outlet orifice, said movable element being able to move in translation in the axial housing in the direction of the first outlet orifice under the effect of a gas pressure exerted on the movable element until the front portion forming the skirt of the movable element protrudes outside the axial housing through the first outlet orifice, and
• the front portion comprises an end portion whose outer diameter gradually decreases towards the second outlet orifice.
• the nozzle of the invention may comprise one or more of the following technical characteristics:
• the front portion further comprises a cylindrical portion of substantially constant outer diameter.
• the end portion comprises at least one chamfer forming an angle (a) with respect to the front face of the nozzle body.
• the angle of the chamfer is between 0.1 and 80 °, preferably between 10 and 45 °.
• the outer profile of the end portion is of frustoconical shape.
• the outer profile of the end portion comprises at least one portion of curvilinear shape.
• the external profile of the end portion comprises at least one portion of convex shape.
• the at least one portion of convex shape has a radius of curvature of between 0.1 and 2 mm.
• the cylindrical portion has an external diameter of between 3 and 8 mm.
• the end portion has an external diameter of between 2.5 and 7 mm at the second outlet orifice.
• the front part forming the skirt of the movable element protrudes outside the axial housing through the first outlet of the front face of the nozzle body.
• the bottom of the axial housing of the nozzle body comprises a shoulder, and the peripheral wall of the movable member comprises a stop, the elastic member being positioned between ⁇ shoulder and the stop.
• At least one sealing element is arranged between the nozzle body and the movable element, for example one or more O-rings.
• said at least one sealing element is arranged in a peripheral groove formed in the outer peripheral wall of the movable element.
• the mobile element is able to move between several positions comprising:
• the axial passage of the movable element has a profile of conical, frustoconical or convergent / divergent shape.
• the nozzle body is made of an electrically conductive material, in particular copper, brass or the like.
• the movable element is formed in whole or in part of an electrically insulating material.
• a movable element is made of an electrically conductive material that is resistant to temperature / heat, in particular copper, brass or the like, the said insulating element comprising at least one insulating interface arranged between the nozzle and the wall of the insert mobile.
• the insulating interface is either a sleeve arranged in the nozzle body, or an insulating coating carried by the nozzle body or the movable member.
• the invention also relates to a laser focusing head comprising at least one focusing optics, for example one or more lenses or mirrors, in particular a focusing lens and a collimating lens, characterized in that it also comprises a nozzle laser according to the invention.
• a laser focusing head comprising at least one focusing optics, for example one or more lenses or mirrors, in particular a focusing lens and a collimating lens, characterized in that it also comprises a nozzle laser according to the invention.
• the invention also relates to a laser installation comprising a laser generator, a laser focusing head and a laser beam conveying device connected to said auditory laser beam.
• laser generator and said laser focusing head characterized in that the laser focusing head is according to the invention.
• the laser generator or source is of type C0 2 , YAG, with fibers or with disks, preferably with fibers or disks, in particular an ytterbium fiber laser source.
• the invention also relates to a method of laser beam cutting, in which a nozzle according to the invention is implemented, a laser focusing head according to the invention or an installation according to the invention. .
• FIG. 1A schematizes a focusing head of a conventional laser cutting installation
• FIG. 1B schematizes the size of the laser spot relative to the size of the nozzle orifice
• FIG. 2 is a sectional diagram of the body of a nozzle according to the invention.
• FIG. 3 is a sectional diagram of a nozzle according to French Patent Application No. 1154224,
• FIG. 4 is a sectional diagram of a nozzle according to one embodiment of the invention.
• FIG. 5 is a sectional diagram of the body of a nozzle according to another embodiment of the invention.
• FIGS. 6A and 6B show the nozzle of the invention with the movable element in two different positions
• FIG. 7 illustrates the displacement of the movable member of a nozzle according to the invention above a vertical drop.
• FIG. 1A shows the focusing head 20 of a conventional laser cutting installation, to which is fixed a conventional laser nozzle 21 which is traversed by a focused laser beam and by assist gas (arrow 23) for expelling the metal melted by the beam out of the cutting groove 31 formed by the beam 22 in the metal piece to be cut 30, for example a sheet steel or stainless steel.
• the assist gas may be an active gas, such as oxygen, air, CO 2 , hydrogen, or an inert gas, such as argon, nitrogen, helium, or a mixture of several such active and / or inert gases.
• an active gas such as oxygen, air, CO 2 , hydrogen
• an inert gas such as argon, nitrogen, helium, or a mixture of several such active and / or inert gases.
• the composition of the gas is chosen in particular according to the nature of the piece to be cut.
• FIG. 1B makes it possible to clearly visualize the section SI of passage of the orifice 24 of the nozzle 21 with respect to the size S2 of the focal spot of the beam 22.
• the section SI is much larger than the size S2 the focal task of the beam 22, which generates, with the conventional nozzles, a high consumption of assist gas which only a small proportion will be used to expel the molten metal out of the cutting groove 31.
• the laser nozzle comprises at least two essential components, namely a nozzle body 1 cooperating with a movable element 2 arranged and movably inside the body 1 of the nozzle, a method of embodiment is illustrated in Figures 2 and 3.
• the nozzle body 1 which is formed of a conductive material, for example copper or brass, is intended to be fixed on the laser focusing head 20 of the laser installation.
• the body 1 of the nozzle is a part of revolution and is traversed right through by an axial housing 5 of axis AA which extends from the rear face lb of the body 1 to the front face of said body 1 .
• the axial housing 5 opens at the two faces before the rear and lb of the body 1 nozzle.
• the rear face lb thus carries a first inlet 11 ', while the front face the door a first outlet 1 1 of the nozzle body 1, the first inlet ports 11' and outlet 11 being coaxial with axis AA.
• This axial housing 5 is in fact a recess, for example of cylindrical shape comprising an internal shoulder 9 projecting radially towards the center of the housing 5, said internal shoulder 9 being formed by a restriction 15 of the section of the axial housing 5 at the first outlet port 11 located on the front face of the nozzle body 1.
• the nozzle FR No. 1 154224 also comprises a movable member 2 which is inserted into the housing 5 of the nozzle body 1, preferably coaxially with the body 1, as visible in FIG. 3.
• This mobile element 2 is suitable for and designed to move in translation along the axis AA inside the housing 5 of the nozzle body 1.
• this movable element 2 comprises a front portion 2a forming a skirt 6 of cylindrical shape, that is to say tubular, arranged in the axial housing 5 of the nozzle body 1 and comprising an axial passage 4 with a second outlet opening 12 opening at the front portion 2 forming said skirt 6.
• the laser beam 22 and the assist gas 23 pass through the axial passage 4 of the mobile element 2 and exit through the second outlet orifice 12 opening at the front portion 2a forming said skirt 6
• the movable element 2 is axially movable relative to the body 1 of the nozzle along the axis AA. In fact, the movable element 2 moves under the effect of the pressure of the assist gas 23 which is exerted on said movable element 2, which tends to push it towards the workpiece 30.
• the gas will be channeled through the skirt 6 and be concentrated at the laser task and thus bleeding, which will greatly improve its efficiency and the expulsion of the metal will be better.
• An elastic element 8 such as a spring, is arranged in the axial housing 5, between the nozzle body 1 and the movable element 2 so as to exert an elastic restoring force on the movable element 2 in a direction tending towards the move away from the workpiece.
• the elastic element 8 thus makes it possible to limit the phenomenon of wear of the skirt 6 during the drilling phases of the sheet which generally precede the cutting phases. Indeed the drilling is most often operated with low gas pressures, typically less than 4 bar. The elastic element then exerts a sufficient restoring force so that the skirt 6 rises completely or almost completely in the housing 5 and is thus protected from splashes of molten metal generated by the drilling.
• the elastic element 8 facilitates rapid movement of the cutting head at a short distance above the sheet, without cutting gas or beam, since the gas pressure then ceases to be exerted on the mobile element and the skirt 6 comes inside the housing 5.
• the movable element 2 comprises a front portion 2a forming a skirt 6 of cylindrical shape, that is to say of constant outer diameter along the axis AA.
• this cylindrical shape is problematic when obstacles, irregularities or thickenings, or unevenness, higher than the level of the upper surface of the sheet to be cut, are present on the surface of the sheet to be cut, for example as a result of splashes of molten metal or cut pieces remained locked in the skeleton of the sheet.
• the outer peripheral wall of the front portion 2a constitutes a wall perpendicular to the surface of the sheet to be cut, i. e. vertical, whose resistance to an obstacle is relatively large, especially at high cutting speeds encountered in laser cutting, typically between 0.1 and 50 m / min, depending on the thickness of the sheet to be cut. It follows a poor absorption of shocks by the skirt 6 and a displacement of said skirt easily hindered, slowed, even braked abruptly or even stopped In other words, the outer profile of cylindrical shape of the skirt favors frontal impacts between the outer surface of said skirt and the obstacles possibly present on the sheet.
• the present invention proposes an improved mobile element laser nozzle, in particular whose front part 2a forming a skirt is adapted to and designed to move over obstacles, irregularities or unevennesses, and this when the movable element is in its working position, that is to say in contact with the upper surface of the sheet to be cut.
• the front portion 2a of said movable member comprises an end portion shaped to pass over a height difference or obstacle without or with a greatly reduced shock at the skirt 6, and without or very little decrease in the speed of movement of the nozzle.
• the front portion 2a comprises an end portion 17 whose outer diameter gradually decreases toward the second outlet orifice 12.
• the front portion 2a is shaped to facilitate its passage over reliefs or obstacles present on the surface of the sheet. Shocks are better absorbed because the gradual decrease in the outer diameter of the end portion 17 promotes the rise of the skirt 6 to the housing 5 when the skirt 6 encounters a drop or a specific obstacle.
• end portion is meant a portion of the front portion 2a located at the end of said front portion, that is to say facing the upper surface of the sheet to be cut.
• the end portion 17 comprises at least one chamfer 18 forming an angle ⁇ with respect to the front face 1a of the nozzle body 1.
• the angle ⁇ of at least chamfer 18 is included between 0.1 and 80 °, preferably between 10 and 45 °.
• the end portion 17 comprises a single chamfer 18.
• the outer profile of the end portion 17 is of frustoconical shape.
• the front portion 2a further comprises a cylindrical portion 16 of substantially constant outer diameter, preferably arranged upstream of the end portion 17, that is to say farther from the second outlet orifice 12 that the portion end 17.
• the external profile of the end portion 17 comprises at least one portion of curvilinear shape.
• the outer profile of the end portion 17 comprises at least one portion of convex shape.
• the radius of curvature of the at least one portion of convex shape is typically between 0.1 and 2 mm.
• the present invention thus makes it possible to eliminate or greatly limit the presence of sharp edges at the end of the front portion 2a.
• the cylindrical portion 16 has an outer diameter preferably of between 3 and 8 mm, more preferably of the order of 6 mm.
• the end portion 17 has an outer diameter between 2.5 and 7 mm, preferably of the order of 4 mm.
• the outer peripheral wall of the movable element 2 comprises an abutment 10, preferably an annular abutment extending over all or part of the periphery of said movable element 2, the elastic element 8 being positioned between the shoulder 9 and the stop 10.
• At least one sealing element 7 is arranged between the nozzle body
• said at least one sealing element 7 is arranged in a peripheral groove 14 formed in the outer peripheral wall of the movable element 2.
• the nozzle of the invention is of standard size, that is to say that its size is not increased compared to a conventional cutting nozzle, which is advantageous and compatible for cuts by nesting, that is to say parts within the same sheet with very little difference between the different parts.
• the nozzle of the invention has the other advantage of being compatible with capacitive sensor systems. Indeed, the copper part or other conductive material adjusts to the height specified by the capacitive sensor, like a standard nozzle. It is the movable insert 2 which, under the pressure of the gas, comes into contact with the sheet 30 to be cut and thus makes it possible to limit the gas leaks.
• the mobile element 2 is preferably formed of an electrically insulating material, composite, technical ceramic, polymer, for example polyetheretherketone (Peek), Vespel®, ceramic or pyrex, and takes the internal geometry of a laser cutting nozzle, that is to say, it can have a conical internal profile, with cylindrical or non-cylindrical outlet channel, frustoconical, convergent / divergent type (ie Laval nozzle) or any other suitable geometry.
• an electrically insulating material composite, technical ceramic, polymer, for example polyetheretherketone (Peek), Vespel®, ceramic or pyrex
• electrically insulating material means a material that does not conduct electricity, that is to say that prohibits the passage of electrical current between two electrically conductive elements.
• the movable element 2 is a piece of revolution formed of a single block of material.
• the movable element 2 is not formed of an electrical insulating material
• at least a portion of the outer surface of the movable element 2 is covered with a layer of electrical insulating material, integral or not with the movable element 2.
• This layer of insulating material then serves as an electrical insulating interface between the movable element 2 and the nozzle body 1.
• the nozzle of the invention comprises a movable element 2 whose output port diameter 12 is between 0.5 and 5 mm.
• the movable element 2 of the nozzle according to the invention is therefore able to move between several positions comprising at least:
• the movable element 2 can occupy intermediate positions in which the skirt 6 only partially projects outside the axial housing 5 of the nozzle body 1. These intermediate positions may in particular be a function of the pressure exerted by the gas on the movable element 2.
• the combination of the specific outer profile of the end of the front portion 2a and the arrangement of the elastic member 8 provides an even greater improvement in the operation of the nozzle of the invention.
• the shape of the extreme portion allows the skirt 6 to pass over a vertical drop or a specific obstacle by promoting the rise of the skirt to the housing 5 and avoids frontal impact with obstacles on the sheet.
• the elastic element 8 limits the pressure exerted by the movable member 2 on the workpiece when it moves towards the workpiece under the effect of the cutting gas. More specifically, the restoring force of the elastic element 8 is advantageously dimensioned so as to keep the movable element 2 in contact with the workpiece while limiting the pressure that said element exerts on the sheet, to greatly minimize or eliminate any risk of deformation of the sheet in which the piece is cut, scratches of the surface of the sheet, and drive the sheet.
• the present invention provides a greater flexibility of movement to the skirt 6 and allows it to follow the level variations that may occur on the surface of the sheet to be cut, which improves its implementation at the industrial level. .
• the solution of the present invention thus leads to a movable element nozzle with enhanced robustness, durability and implementation compared to a nozzle according to the document FR No. 1 154224.
• the laser focusing head is equipped, as the case may be, with a standard nozzle with an outlet orifice of 1.8 mm in diameter or with a nozzle according to FIG. 3 with a cylindrical movable skirt and axial passage with a conical profile with a channel.
• cylindrical outlet 1.8 mm in diameter the outer profile of the movable skirt comprises a chamfer at an angle of about 30 ° to the horizontal, i. e. relative to the front face of the nozzle body.
• the assist gas used is nitrogen.
• the cutting sheet is made of 304 L stainless steel 5 mm thick.
• a height difference of 0.8 mm is simulated on an area of the sheet to be cut by covering a portion of the sheet to be cut by another piece of sheet metal 0.8 mm thick, as shown schematically in Figure 7. .
• 0.8 mm is typically my maximum height of unevenness or obstacles that can be on a sheet cut by laser beam.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Mechanical Engineering (AREA)
• Laser Beam Processing (AREA)

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Citations (8)

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• 2012
  • 2012-04-04 FR FR1253089A patent/FR2989013B1/fr not_active Expired - Fee Related
• 2013
  • 2013-02-13 ES ES17197254T patent/ES3031761T3/es active Active
  • 2013-02-13 US US14/504,883 patent/US9616525B2/en active Active
  • 2013-02-13 WO PCT/FR2013/050291 patent/WO2013150195A1/fr not_active Ceased
  • 2013-02-13 CA CA2868207A patent/CA2868207C/fr active Active
  • 2013-02-13 CN CN201380018766.6A patent/CN104220209B/zh active Active
  • 2013-02-13 EP EP17197254.0A patent/EP3300831B1/fr active Active
  • 2013-02-13 JP JP2015503911A patent/JP6158299B2/ja active Active
  • 2013-02-13 RU RU2014144368A patent/RU2014144368A/ru not_active Application Discontinuation
  • 2013-02-13 SG SG11201406302SA patent/SG11201406302SA/en unknown
  • 2013-02-13 PL PL17197254.0T patent/PL3300831T3/pl unknown
  • 2013-02-13 KR KR1020147030545A patent/KR20140142348A/ko not_active Withdrawn
  • 2013-02-13 IN IN8591DEN2014 patent/IN2014DN08591A/en unknown
  • 2013-02-13 AU AU2013244880A patent/AU2013244880B2/en not_active Ceased
  • 2013-02-13 EP EP13708204.6A patent/EP2834035B1/fr active Active
  • 2013-02-13 MX MX2014011942A patent/MX2014011942A/es unknown
• 2014
  • 2014-10-02 ZA ZA2014/07158A patent/ZA201407158B/en unknown

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