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
  • B23K26/0884—Devices involving movement of the laser head in at least one axial direction in at least two axial directions in at least in three axial directions, e.g. manipulators, robots
• • 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
  • B23K26/0823—Devices involving rotation of the workpiece

Definitions

• the invention relates to a laser beam welding apparatus according to the preamble of claim 1 and to a laser beam welding method according to the preamble of claim 10.
• the laser beam is focused in the joining zone (welding zone) of two or more workpieces to be welded.
• the absorption of the laser beam leads to heating and melting and often to partial evaporation of the material.
• the welded connection is formed from the mixing of the melt occurring during the joining of several workpieces and the subsequent re-solidification of the material. Due to the local thermal expansion, possibly a structural transformation and the solidification of the material occurs undesirable delay, which can lead to the component consisting of the workpieces to shape and dimensional changes and thus to functional impairments and in the worst case to failure of the component.
• welding dissimilar materials i. Different materials can cause cracks due to different thermal expansion coefficients during welding.
• One approach to reducing component distortion is the homogeneous introduction of energy, i. a uniform symmetrical heating of the joining zone, as is known for example from DE 100 20 327 Al.
• the invention has for its object to propose a laser beam welding apparatus, which is suitable for welding two metal workpieces. Furthermore, the object is to propose a correspondingly improved laser beam welding process.
• the invention has recognized that the threshold speed from which a uniformly melted joining zone is formed depends on the component geometry, the melting temperature and the thermal conductivity of the material to be joined or the materials to be joined. Furthermore, the invention has recognized that as a result, depending on the material, a more or less large outflow of energy or heat in the Material results and in the joining zone use cooling and solidification. In addition, the invention has recognized that in order to generate or to obtain the molten state, the introduced energy flow must be at least as great as the outflowing energy flow.
• the method using a laser scanner for metallic materials was not practical, since the higher thermal conductivity of metal and the associated higher energy loss by the outflow of heat into the component significantly faster speeds of the laser beam or the focal point are required than with A conventional laser scanner can be reached.
• the basic idea is not only to move the focus of the laser beam along a predetermined path in a first direction of movement on a workpiece, or in the joining zone of at least two workpieces, but in addition to drive the workpiece or the workpieces in a second direction of movement, such that there is an increased relative speed between the focus of the laser beam and the or to be joined workpieces.
• the laser beam welding method according to the invention provides for this drive means for driving the workpiece or the workpieces in the second direction of movement.
• the drive means are designed and arranged such that they drive the at least one workpiece together with a corresponding fixing device for holding, ie fixing the at least one workpiece. Due to the increased relative speed between the focus of the laser beam and the workpiece or the joining region, a uniform heating along the entire joint region and thus a uniform Melting of the at least one workpiece can be realized.
• the laser beam welding apparatus according to the invention and the laser beam welding method according to the invention are suitable for welding metallic workpieces, in particular of different metals or metal alloys.
• laser beam sources can be used with a lower power output to achieve a certain welding depth than when welding workpieces with only a single run over. For example, the use of medium power CW lasers is possible.
• Particularly high relative speeds between the focus of the laser beam and the at least one workpiece can be realized by moving the first direction of movement with which the laser beam is moved along the predetermined path in the joining area and the second direction of movement in which the workpiece or workpieces are moved. is driven / are opposite to each other, so the focus of the laser beam and the workpiece are moved in opposite directions.
• the laser beam welding device or the laser beam welding method is particularly suitable for producing annular, ie circumferentially closed welds, wherein the welds to be generated, for example, on a flat surface, such as a workpiece front side or on the circumference of at least one workpiece can be generated.
• the at least one workpiece is preferably driven in rotation with the drive means about an axis of rotation.
• the axis of rotation about which the workpiece rotates along a, in particular, circulating path, in order to be able to uniformize the energy input even with complex workpiece geometries.
• the web which is run over by the laser beam when the workpiece is driven in rotation, is not closed. This can be realized, for example, by turning off or deflecting the laser in a certain circumferential section.
• the laser beam welding device is designed such that a circumferentially closed, ie annular, weld seam is produced is particularly preferred.
• the path on which the focus of the laser beam moves is circular.
• a circular-shaped track is particularly suitable for welding rotationally symmetrical workpieces.
• the workpieces to be welded are preferably moved rotationally about a rotation axis.
• the path along which the laser beam or the laser beam focus is movable in the joining region is programmable.
• the path is programmed such that the path corresponds at least approximately to the contour of the workpiece - in particular taking into account the rotational movement of the workpieces.
• the means for imaging the path of the laser beam focus on the circumference of the at least one workpiece as a cone mirror or parabolic Mirrors are formed or comprise a cone mirror and / or a parabolic mirror, wherein the cone mirror or the parabolic mirror, depending on whether the weld on the Au ⁇ z- or inner circumference of the workpieces is to be generated, is preferably designed as an inside or outside mirror.
• a conical or parabolic mirror is advantageous; however, other geometric mirror shapes for deflecting the laser beam onto the circumference of the at least one workpiece can also be provided.
• the shape of the means for imaging the sheet on the periphery in particular the shape of the conical mirror, or to the contour of the workpiece or of the workpieces to adapt the weld to be produced.
• FIG. 1 shows a laser beam welding apparatus for producing a frontal weld
• Fig. 2 shows a laser beam welding apparatus for generating a is arrange ⁇ th at the outer periphery of a workpiece and the weld seam
• Fig. 3 shows a laser beam welding apparatus for generating a is arrange ⁇ th on the inner circumference of a workpiece weld.
• a laser beam welding apparatus 1 comprises a laser scanner 2 with a laser beam source for generating a laser beam 3 and for moving, ie moving the laser beam 3 along a predetermined, in this embodiment frontal, annular path between a first workpiece 4 and a front, designed as a lid second Workpiece 10.
• a laser beam welding apparatus 1 By means of the laser beam welding apparatus 1 shown, an annular, lying in a frontal plane weld between the workpiece 4, 10 can be generated.
• the laser beam 3 or the focus 5 of the laser beam 3 is moved at a speed of approximately 60 m / min in a first direction of movement 6 in the counterclockwise direction in this exemplary embodiment.
• the first workpiece 4, together with the second workpiece 10, is driven in a clockwise direction by means of drive means 7 about a rotation axis D in a second direction of movement 8, which is opposite to the first direction of movement 6.
• the workpieces 4, 10 are melted homogeneously in the annular joining region 9.
• both are the first Workpiece 4 and designed as a lid second workpiece 10 made of steel.
• FIG. 2 shows an alternative laser beam welding device 1.
• This comprises a laser scanner 2 for generating and processing a laser beam 3.
• the laser beam 3 is driven in a counterclockwise direction in a first direction of rotation 6 rotating.
• the laser beam 3, which is emitted approximately in the axial direction, strikes a cone mirror 11 with an inner cone and is deflected by the latter in the radial direction inwardly onto the outer circumference 12 of the first and the second workpiece 10, so that the focus 5 in the first movement direction 6 in the circumferential direction on the outer circumference 12 of the abutting workpieces 4, 10 moves.
• the workpieces 4, 10 are rotatably rotated by means of drive means 7 about the axis of rotation D in a second direction of movement 8 in a clockwise direction.
• the embodiment according to FIG. 3 essentially corresponds to the exemplary embodiment according to FIG. 2, with the difference that the laser beam 3 or its focus 5 on the inner periphery of the workpieces 4, 10 is moved counterclockwise along a first direction of movement 6.
• a cone mirror 11 with an outer cone is arranged inside the hollow cylindrical workpieces 4, 10, so that the laser beam 3 impinging on the cone mirror 11 from the axial direction points radially outwards onto the inner circumference 14 in the joining region 9 in the contact region of the workpieces 4, 10 hits.
• the workpieces 4, 13 are rotated by means of the drive means 7 rotationally into a second, the first direction of movement 6 opposite direction of movement 8 driven in a clockwise rotational direction.

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

Applications Claiming Priority (2)

Publications (1)

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• 2007
  • 2007-07-13 DE DE102007032744A patent/DE102007032744A1/de not_active Withdrawn
• 2008
  • 2008-07-02 US US12/599,210 patent/US20100282722A1/en not_active Abandoned
  • 2008-07-02 KR KR1020107000741A patent/KR20100035164A/ko not_active Application Discontinuation
  • 2008-07-02 WO PCT/EP2008/058526 patent/WO2009010388A1/de active Application Filing
  • 2008-07-02 EP EP08774660A patent/EP2170550A1/de not_active Withdrawn
  • 2008-07-02 JP JP2010516447A patent/JP5254330B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

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