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
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
  • B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
• • 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
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
• • 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
  • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
  • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
  • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
  • B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses

Definitions

• the invention relates to a device for guiding a laser beam for machining a workpiece, wherein the laser beam is directed via a mirror arrangement and a focusing optical arrangement on by suitable alignment of the mirror assembly preselectable processing points on the workpiece.
• Laser radiation for processing materials is exemplified for marking, for
• Drilling of printed circuit boards, used for welding plastic parts or for sintering In the processing of materials by means of the laser radiation, the radiation can be directed by means of a so-called scanner with two substantially mutually orthogonal rotatable scanner mirrors to selectable positions on a workpiece. The steering is done so that a selectable scan
• the scan field can be achieved on the workpiece in two or three dimensions, the scan field is usually two-dimensional, but also an extension in three dimensions is possible.
• the focusing of the laser radiation can be done with a flat field objective, which focuses the laser radiation in a plane on the object. The location of the focus depends among other things on the angle of incidence of the laser radiation in the
• the scanner mirrors are usually arranged as close as possible to the objective in order to obtain the largest possible processing field from vignetting of the radiation through the objective.
• the angle of incidence of the laser radiation is irrelevant in the case of a flat workpiece, but can certainly be significant for the machining of a three-dimensionally shaped workpiece.
• the angle of incidence of the laser radiation on the focal plane is thus perpendicular to a plane workpiece on the optical axis of the assembly, is inclined away from the optical axis of this and increases towards the edge of the processing field towards.
• the focusing of the laser radiation on the workpiece can also take place with a telecentric lens, in which the incident radiation impinges on the workpiece substantially perpendicularly in the entire processing field.
• these telecentric lenses are associated with higher acquisition costs and still cause some shading, so they do not solve the task of the invention satisfactorily.
• Special lenses for machine vision have a beam path with on the object side inwardly inclined to the optical axis rays. These lenses are not suitable for use with high-power laser radiation since they do not have the necessary coating of the lenses.
• a disadvantage of the arrangements currently used for beam guidance is that with three-dimensional objects, for example in the area laterally of the optical axis, but also on the optical axis, part of the laser radiation can be shaded by the object. This can result in reduced machining quality or damage to the workpiece if a raised part of the workpiece is struck by laser radiation. According to the prior art, therefore, the laser radiation is directed to the object via laterally mounted additional mirrors. This requires a precise adjustment and can lead to problems because of the contamination of the cassette mirror.
• Trepanieroptik be used, in which over three wedge plates lateral displacement of perpendicular to the workpiece incident laser radiation can be achieved.
• these opto-mechanical systems are complex and therefore associated with high costs.
• the object of the invention is achieved in that the mirror arrangement is arranged further away than the simple focal length from the main optical plane of the optical arrangement.
• a so-called F-theta lens is used in many cases, the incoming radiation in a focal point at a distance to the optical axis approximately proportional to their entrance angle on a
• the mirrors are positioned as close as possible to the focusing optical arrangement in order to be able to realize large entrance angles and thus a large processing area.
• the laser radiation impinges off the optical axis at an angle away from the optical axis and can therefore be shaded by elevations on the workpiece.
• the laser radiation impinges off the optical axis at an angle facing the optical axis. This is achieved by placing the scanner mirrors farther from the focussing optical assembly than is provided in the prior art.
• the mirrors are mounted within the simple focal length of the focusing optical assembly so that the desired large processing zone can be achieved.
• the light path is inclined away from the optical axis, wherein the angle increases with increasing distance from the optical axis.
• the emerging rays would be oriented substantially parallel to the optical axis.
• the exiting rays are inclined as desired to the optical axis and it can be edited positions on the workpiece without a Doubleabschattung by a survey in the middle of the workpiece. It is also possible with simple lenses to meet the requirements, such as when welding plastic components, in which often a focus diameter of 1 millimeter or larger sufficient. With the arrangement, it is possible by way of example to weld two nested tubes together.
• the mirror arrangement has two movable mirrors, each with an axis of rotation, the mirrors can be moved particularly quickly with a galvanometric drive and thus the laser beam can be positioned and guided on the machining points on the workpiece. It is thus a short processing time, high processing or traversing speeds (for example, Quasisimultan-
• the focusing optical arrangement is designed as a flat field objective. If a flat-field objective, which can be an F-theta objective, is used, the laser radiation on a flat working plane can also be achieved on a workpiece with a low focus diameter or a better imaging quality. If a simpler focusing optical system is used, this focuses the laser light, for example, on a spherical shell, so that a larger focal point is produced in the area away from the optical axis or the workpiece or optics must be tracked accordingly.
• a flat-field objective which can be an F-theta objective
• the mirror arrangement is embodied as two essentially mutually orthogonal deflection mirrors or as gimbal-mounted individual mirrors.
• Figure 3 shows a beam path during a processing of two tubes.
• FIG. 1 shows a first scanner arrangement 10 according to the prior art for processing a workpiece upper part 19 and a workpiece lower part 16, by means of serstrahlung.
• the workpiece upper part 19 has a base plate facing the workpiece base 16, which is welded to the workpiece base 16.
• Light from a laser source is fed in the scanner arrangement 10 by means of at least one deflection mirror 11 as an incident beam 12 to a focusing lens 13 which transmits the laser light as the first emergent beam 14 on the base plate of the
• a deflecting mirror 1 1 is shown here.
• the deflection mirror 1 1 is arranged at a first mirror distance 17 from the focusing lens 13, so that it lies within the simple focal length of the focusing lens 13.
• the first outgoing beam 14 is inclined away from an optical axis 18, wherein the inclination angle increases with the distance of the impact point on the workpiece upper part 19 from the optical axis.
• the workpiece In the exemplary embodiment illustrated here, the workpiece
• FIG. 2 shows a second scanning arrangement 20 with the arrangement improved according to the invention. Same components as in Figure 1 are provided with the same reference numerals.
• the deflection mirror 11 is arranged in a second mirror spacing 21 which is larger than the first mirror spacing 17.
• the incident beam 12 strikes the focusing lens 13 farther away from the optical axis 18 than in the first scanner assembly 10.
• the focal length of the focusing lens 13 is identical to the arrangement of Fig. 1 and, as a first approximation, the focusing lens 13 is an F-theta Objectively behaves, the laser beam as the second outgoing beam 22 is tilted inwards to the optical axis 18 to the same point on the workpiece as in Figure 1.
• the second emerging beam 22 passes through the workpiece elevation on the workpiece upper part 19 in a free beam area 23 and is focused on the workpiece upper part 19 with the beam quality required for the machining.
• the smallest possible focal length of the focusing lens 13 can be used to NEN as strong as possible to the optical axis inclined impact angle to achieve.
• a reduction of the beam diameter can be useful in the context of an optimization.
• a focusing lens 13 a commercially available flat field objective, for example, a so-called F-theta lens can be used.
• FIG. 3 shows an example of the use of the material processing apparatus according to the invention with a laser beam.
• a first pipe section 31 is introduced into a second pipe section 33 and both pipe sections 31, 33 are to be connected to one another at a circumferential weld seam 32.
• laser radiation 30 impinges on the weld seam 32 at an angle inclined toward the optical axis 18. Due to the inclination of the laser radiation 30 to the optical axis 18 towards a shadowing of the laser radiation 30 through the first pipe section 31 is avoided.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Mechanical Engineering (AREA)
• Laser Beam Processing (AREA)
• Endoscopes (AREA)
• Lenses (AREA)
• Mechanical Light Control Or Optical Switches (AREA)

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Publications (1)

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ID=51033148

Family Applications (1)

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Citations (4)

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• 2013
  • 2013-08-06 DE DE102013215442.9A patent/DE102013215442A1/de not_active Withdrawn
• 2014
  • 2014-06-17 CN CN201480045031.7A patent/CN105473271A/zh active Pending
  • 2014-06-17 KR KR1020167003351A patent/KR20160040205A/ko not_active Withdrawn
  • 2014-06-17 JP JP2016532272A patent/JP2016531004A/ja active Pending
  • 2014-06-17 WO PCT/EP2014/062679 patent/WO2015018552A1/de not_active Ceased
  • 2014-06-17 ES ES14734037T patent/ES2869908T3/es active Active
  • 2014-06-17 EP EP14734037.6A patent/EP3030375B1/de active Active
  • 2014-06-17 US US14/907,144 patent/US20160158887A1/en not_active Abandoned

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