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
  • B23K26/14—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
• • 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
  • B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
  • B23K26/044—Seam tracking
• • 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
  • B23K26/082—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head

Definitions

• the invention relates to a device with a scanner optics (pre- or post-objective scanning) equipped for material processing by laser, in particular for laser welding, which recognizes the processing positions on the workpieces to be machined independently and with little error by means of a sensor. This makes it possible to compensate for machine- and workpiece-related positioning errors using the scanner optics.
• a scanner optics pre- or post-objective scanning
• This makes it possible to compensate for machine- and workpiece-related positioning errors using the scanner optics.
• With the device mass production uncomplicated geometry pattern with high resolution, such as. B. fine KeN and flanged seams, are manufactured, which previously required a very large effort.
• scanner optics with deflection units for lasers which enable positioning of the laser processing beam by adjusting the deflection units.
• deflection units usually mirrors are used.
• Significantly higher speed and acceleration characteristics can be achieved with scanner optics than with guide machines; on the other hand, they make it possible to write seams and contours on the workpieces to be machined during the movement of the guide machine, independently of this. As a result, the production times can be lowered sustainably.
• Scanner optics work either on the principle of pre-objective scanning or post-objective scanning.
• the divergent laser beam first passes through a collimation unit, is then deflected via one or more active (adjustable) deflection units and finally imaged via a focusing on the workpiece to be machined.
• the focusing unit is equipped with an optical lens or a plan-field lens.
• Scanner optics according to the principle of post-objective scanni ⁇ g also have a collimation unit, but the focusing unit is at least before a deflection unit, ie by the deflection unit, the already focused laser beam is positioned on the workpiece.
• passive (fixed) deflection units which serve to guide the beam are often used in the scanner optics.
• the scanner optics are usually used relative to the moving workpieces. Either the scanner optics is stationary and the workpiece moves relative to this or the scanner optics is moved by means of a guide machine and das.Werk consultancy is fixed in place.
• the actual vector of the relative velocity and the actual Cartesian position between the workpiece processing point and the scanner optics must therefore be known to the scanner optics in order to first determine the starting point for the laser spot and then track it according to the geometry programming. While the vector of the relative velocity can still be determined comparatively accurately, the position of the scanner optics relative to the workpiece is severely flawed due to elastic deformations of the arrangement, the limited resolution of the displacement sensors of the guide machine, manufacturing tolerances of the workpieces and positional deviations of the workpiece caused by the tensioning device ,
• the object of the invention is to find a device equipped with a scanner optics for material processing by means of laser, which detects processing positions on the workpieces to be machined independently and poor in error.
• a scanner optics for material processing by means of laser which detects processing positions on the workpieces to be machined independently and poor in error.
• the starting point is a device for material processing by means of a laser, in particular for laser welding, with a scanner optic movable relative to the workpiece to be machined by a guide machine.
• the scanner optics is either stationary and the workpiece is moved relative to this or the workpiece is stationary and the scanner optics is moved by means of a guide machine.
• the scanner optics whose beam path is defined by one or more active and / or passive deflection units, operates either on the principle of pre-objective scanning or post-objective scanning.
• the device comprises a projector which serves to project measurement light in the form of measurement structures onto the workpiece to be processed, and an image sensor which is sensitive in the wavelength range of the measurement light emitted by the projector.
• the projector and the image sensor are connected to the scanner optics and thus are moved during operation of the device with the scanner optics.
• the image sensor is integrated with the part of the beam path of the scanner optics, which starts at the impact position on the workpiece.
• the image sensor is arranged on the side of a deflection unit (hereinafter: behind) which is transparent to the wavelength range of the light emitted by the projector and reflects the light out of the wavelength range of the processing laser.
• the image sensor behind a passive deflection and use as a light source for the projector, a laser emitting light of a different wavelength than the processing laser, as well as to perform the passive deflection as partially transmissive mirror, which is provided with interference layers, these being the light reflect the laser and let through the light of the projector laser.
• the optical path is from the point of view of the processing location, i. in the direction starting at the machining location on the workpiece and ending at the laser, defined.
• Particularly suitable for decoupling the sensor signal is that passive deflection unit which is arranged in the beam path behind the last active deflection unit of the scanner optics or the passive deflection unit which follows directly in the beam path to the focusing.
• the measuring field of the sensor is moved synchronously in all available degrees of freedom with the laser processing beam. Since the laser processing beam in the scanner optics runs coaxially or approximately coaxially to the axis of incidence of the sensor in at least one area of the optics, position and geometry errors from the overall optical or mechanical structure can not affect the measurement result. Since, in the simple embodiment, the projector is stationary, but the area monitored by the sensor on the workpiece can be positioned over the deflection units in the entire field of operation of the scanner optics. it is only possible to detect the measuring light projected onto the workpiece by the sensor when the deflection units are aligned such that the measuring light impinges on the measuring field of the sensor. To overcome this limitation across the seam longitudinal direction, a projector is used which projects onto the workpiece lines transverse to the longitudinal direction of the seam to be formed on the workpiece, the lines extending over the entire working field of the scanner optics.
• the measuring light contains one or more projection lines, the number of lines depending on the required correction dimensions.
• the height difference, the offset transverse to the seam longitudinal direction and the rotation about the seam longitudinal direction can be determined, while with three measuring lines all spatial dimensions can be determined.
• the lines of the measuring light must always maintain a distance to the position of incidence of the laser beam. In particular, they must not cross the laser beam. This requirement is achieved in that a distance in the longitudinal direction of the seam can be specified by the projector. In terms of process technology, it is favorable if the projection line always has a flow with respect to the processing point.
• the device is equipped with a control unit which calculates the machining positions on the workpiece by means of triangulation and / or light-slit method from the sensor data and controls the active deflection units of the scanner optics by means of this position data.
• a control unit which calculates the machining positions on the workpiece by means of triangulation and / or light-slit method from the sensor data and controls the active deflection units of the scanner optics by means of this position data.
• the scanner optics is mounted on the guide machine and is moved by this relative to the workpiece.
• the process speed thus necessarily coincides with the speed (guide speed) determined by the guiding machine.
• the active deflection units of the scanner optics are synchronized with the guide machine with the aid of the control unit in such a way that, in addition to the seam guide, the process speed is reduced or increased compared to the guide speed with the scanner optics can be moved by the laser beam with the scanner optics in or against the predetermined direction of the guide machine movement.
• the active deflection units of the scanner optics are pivoted so far in the feed direction that the measuring light line / measuring light lines is / are positioned at the lower end of the sensor measuring field.
• the seam guide is started at this end and the required process speed is synchronized with the actual movement of the guide machine by means of a compensation movement in the feed direction, realized by the scanner optics.
• the guide speed is usually higher than the process speed.
• the projection line travels from the lower end of the sensor measuring field to the upper end. With sufficiently linear workpiece contours, the compensation movement can also be extrapolated beyond the field of view of the sensor / camera image.
• the projector can also be actively positioned in the seam longitudinal direction via one or more separate projector degrees of freedom. This makes it possible on the one hand, to keep the flow between the measuring light lines from the projector and the laser spot and thus the sensor measuring field variable, on the other hand, by exploiting the entire scanner field by means of a synchronized movement between the projector and deflection units of the scanner optics a larger Seam guiding area in the seam longitudinal direction obtained or can a greater difference between the leadership and process speeds can be achieved.
• the device may be equipped with at least one Jerusalem jet.
• the process jet uses compressed gas (compressed air) to create a flow of air that moves the process environmental effects out of the surrounding area of the projector.
• the process jet like the projector, is connected to the scanner optics and is therefore moved together with the projector.
• a stationary mounted process jet, multiple process jets, or a process jet that is pivotally mounted like the projector used is used.
• Fig. 1 lateral view
• Fig. 2 top view
• Fig. 3 view from the front.
• the light emitted by the processing laser 1 enters the scanner optical system 2b operating according to the construction principle of the post-objective scanning, is collimated with the collimation unit 3 and coupled to the passive deflection unit 4a (FIG. executed as a partially transparent mirror) directed to the focusing unit 5.
• the laser processing beam 6 is focused and, in the further course of the beam path, strikes the active deflection unit 4b (embodied as a mirror), which directs the beam 6 onto the workpiece 7 to be machined.
• the impact position 8 of the beam 6 on the workpiece 7 can be changed; the maximum range to which the impact position 8 can be steered by means of the deflection unit 4b defines the working field 9 of the scanner optics 2b.
• the projector 10 which is mechanically connected to the scanner optics, irradiates measuring light 11 generated by a laser in the form of projection lines 12 which extend transversely to the longitudinal direction 13 of the seam onto the workpiece 7.
• the projector 10 has degrees of freedom 14 in the longitudinal direction 13 and also degrees of freedom 15 which allow pivoting about the target machining position 16, thereby enabling continuous seam tracking even at small radii or at edges.
• the passive deflection unit 4a Since the passive deflection unit 4a is permeable to the lens 10 of the projector 10, it passes through it and passes through the designed as a lens sensor focusing unit 17 on the sensor measuring field 20 of the optical image sensor 18. When passing through the sensor focusing unit 17, the light is focused. The course of the received laser light defines the receiving beam 19 of the sensor 18.
• the process jet 21 uses compressed gas 22 to blow away as much as possible from the projector 10 as much as possible due to the laser welding process environmental influences 23.

Applications Claiming Priority (3)

Publications (1)

Family

ID=42338872

Family Applications (1)

Country Status (5)

Families Citing this family (20)

Citations (1)

Family Cites Families (12)

• 2009
  • 2009-11-27 DE DE102009057209A patent/DE102009057209B4/de active Active
• 2010
  • 2010-01-21 WO PCT/DE2010/000057 patent/WO2010088873A1/de active Application Filing
  • 2010-01-21 EP EP10715656A patent/EP2393626A1/de not_active Withdrawn
  • 2010-01-21 CN CN201080007258.4A patent/CN102307698B/zh active Active
• 2011
  • 2011-08-08 US US13/205,297 patent/US20110290780A1/en not_active Abandoned

Patent Citations (1)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events