Laser processing head having a scanner unit or scanner assembly

Abstract

The present invention relates to a laser processing head (20) having a scanner unit, the scanner unit comprising: a mirror unit having a scanner mirror (242) with a circumferentially extending groove (2432), a frame (241) fixable within the processing head (20) of a laser processing system (10), the mirror unit being movably mounted within the frame (241), and an annular resilient sealing element (245) fixed to the frame (241) on an outer periphery of the sealing element and engaging with the circumferential groove (2432) on an inner periphery of the sealing element. The present invention further relates to a sealing element (245) for the scanner unit and an additional laser processing head having a scanner assembly (24).

Description

[Technical Field]

[0001] The present invention relates to the field of laser processing of workpieces, preferably laser cutting of metal workpieces. In particular, the present invention relates to a laser processing head, particularly a laser cutting head, having a scanner unit or scanner assembly for dynamically deflecting a laser beam within the laser processing head. [Background technology]

[0002] Scanner systems in which a laser beam is dynamically deflected within a laser processing head by controlled tilting of one or more scanner mirrors are state-of-the-art. For example, it is known to place a deflection mirror in the collimated beam-guiding region of the laser processing head, which can be independently and dynamically tilted about both horizontal axes. A highly integrated design involves a scanner mirror mounted as a rotor assembly with four magnet pairs distributed around a circumference containing an iron yoke. The rotor is suspended by four solid joint arms and is deflected or tilted around its initial position by four coils (stators) located opposite the magnets. During scanner mirror movement, particle formation can occur, particularly due to wear between the assembly's movable components. To meet cleanliness requirements within the laser processing head, which require virtually no foreign matter to be deposited within the optical space, the semi-clean backspace of the scanner assembly must be effectively shielded from the optical space of the laser processing head.

[0003] From DE 10 2016 210 698 A1, an arrangement for EUV lithography is known, in which at least one reflective optical element is movably mounted in a housing, the casing at least partially encloses a holder for the optical element and a base, seals the actuator space from the optical space, and the casing has at least one flexible part that allows movement of the optical element. The flexible part can be formed by a flexible plastic component. For fastening purposes, the casing can be glued to the base or fixed in a force-fit or form-fit manner, for example, clamped with a spiral spring or a clamping ring.

[0004] WO2019145536A1 describes various variants of how a laser beam can be moved over short distances at high frequencies within the nozzle of a laser processing head, for example with the aid of a scanner mirror.

[0005] EP 4000789 A2 describes an optical device having a carrier and a scanner mirror movably fixed to the carrier, wherein a sealing membrane forms an airtight connection between the scanner mirror and the carrier.

[0006] Object of the invention The present invention aims to improve upon the prior art by providing effective shielding of the optical space of a laser processing head from the actuator or drive space of a scanner unit or scanner assembly, with the objective of minimizing the impact on the kinematics of the scanner mirror. Specifically, the suitability of existing scanner systems for use in multi-kilowatt laser cutting systems is improved.

[0007] Summary of the Invention To achieve the object underlying the present invention, a laser processing head, specifically a laser cutting head, having a scanner unit is provided according to a first aspect. The scanner unit includes a mirror unit having a scanner mirror, the mirror unit having a circumferential groove. The mirror unit can preferably have a mirror mounting portion disposed on the outer periphery of the scanner mirror. The scanner mirror can preferably be firmly connected to the mirror mounting portion, for example, by adhesive connection. The circumferential groove can then preferably be disposed on the outer periphery of the mirror mounting portion.

[0008] As a rule, the laser processing head comprises at least one entrance opening for the laser beam, an optical space through which the laser beam is guided through the laser processing head by optical elements, in particular lenses and / or mirrors, and an exit opening through which the laser beam leaves the laser processing head. A scanner unit with a scanner mirror as the beam-guiding optical element is arranged in this case adjacent to the optical space of the laser processing head.

[0009] The scanner unit comprises a frame that can be fixed in the laser processing head, and the mirror unit is movably mounted in the frame. Specifically, the frame and the mirror unit can be arranged in a common plane of the scanner unit, and the frame laterally surrounds the mirror unit. Specifically, the frame can form a lateral housing for the scanner unit.

[0010] The scanner unit further includes an annular resilient sealing element secured to the frame along its outer periphery and engaging a circumferential groove along its inner periphery, the sealing element preferably being flat.

[0011] The proposed solution allows for a particularly compact and lightweight design of the scanner unit within the laser processing head. The sealing element effectively seals the gap between the mirror unit and the frame against the passage of particles, which may be created by the relative movement of the mechanical components of the mirror suspension and the drive unit, which is preferably arranged between the frame and the mirror unit and is designed to tilt the mirror unit. The sealing element shields the optical space of the laser processing head from the movable drive components of the scanner unit, thereby reducing the likelihood of optical failure due to foreign objects. The seal also allows for the application of cooling gas to the mirror unit and / or the drive unit at the rear side of the scanner unit facing away from the optical space. This option is particularly advantageous when the scanner unit is used in multi-kilowatt laser processing systems.

[0012] The scanner mirror including the mirror mount and the drive unit can be designed, for example, as described in EP 4000 789 A2, with the magnet pair of the scanner drive preferably being arranged on the mirror mount.

[0013] The sealing element may preferably have a corrugated cross section. The corrugated cross section may reduce the deformation stiffness of the sealing element, which may also be referred to as a sealing membrane. In this way, the resistance when the mirror unit is tilted may be reduced, and the dynamics of the scanner unit may be improved. Specifically, the sealing element may have at least one corrugation in its cross section, which is designed to remain even when the mirror unit is fully deflected.

[0014] The circumferential groove of the mirror unit preferably has a cross section that tapers toward the groove base. In this case, the groove base refers to the deepest point of the groove, i.e., in the case of a cylindrical mirror unit, the point where the groove has its smallest diameter. Specifically, the circumferential groove can have a trapezoidal cross section. Furthermore, the sealing element can have a first thickened portion along its inner circumference that is formed to be complementary in shape to the groove. In this case, this should be understood as specifically having a wedge-shaped or trapezoidal thickened portion with an outer slope that has substantially the same inclination as the outer wall of the groove. The engaging slopes of the thickened portion and the groove ensure an improved fit and adhesion of the snap connection between the sealing element and the mirror unit. Furthermore, the trapezoidal connection shape has proven particularly advantageous with regard to the desired mass reduction.

[0015] It can be particularly advantageous if the first thickness of the sealing element has a greater width at the base of the groove than the groove, which ensures that the sealing element engages or snaps into the groove accurately.

[0016] Furthermore, it may be preferable that the inner circumference of the sealing element in its relaxed state is smaller than the circumference of the groove at the base of the groove, specifically at least 2% and / or at most 20% smaller. For example, the inner circumference of the sealing element may be about 10% smaller than the circumference of the base of the groove. In this way, when the sealing element is installed in the scanner unit, it is under tension along its inner circumference and is forced into the groove.

[0017] The sealing element can also be glued to the mirror unit in the groove along the inner periphery of the sealing element. Specifically, the thickened portion of the sealing element along the inner periphery can be wetted with adhesive when inserted into the groove. The bonding can further improve the adhesion of the sealing element in the groove, thereby improving the sealing effect.

[0018] The sealing element can have a second thickened portion along its outer periphery. The second thickened portion can be clamped along the inner periphery of the frame. The second thickened portion can have, for example, a circular cross section. To form a clamping connection with the sealing element, the frame can have a circumferential recess along its inner periphery, into which the second thickened portion can be received and secured by a clamping ring.

[0019] To achieve the object underlying the present invention, a second aspect provides a sealing element for a scanner unit of a laser processing head according to one of the above-mentioned variants. The sealing element comprises an annular base body made of an elastic material, the base body having a first, specifically trapezoidal, thickened portion along the inner periphery of the base body, and a second, specifically circular, thickened portion along the outer periphery of the base body. The shape specification of the thickened portion refers to the cross-sectional shape of the base body in the circumferential direction.

[0020] In the relaxed state of the sealing element, the substrate preferably has a corrugated cross section. By forming at least one corrugation on the substrate of the sealing element, resistance to movement of the mirror unit with which the sealing element is engaged is reduced. Particularly preferably, the substrate has at least one corrugation in cross section with an inner diameter of at least 0.5 mm and / or at most 2 mm, preferably about 1 mm to 1.5 mm. The corrugation can be formed on the substrate as either a bump or a depression. The corrugation should generally be as small as possible to minimize the mass of the substrate. Overall, the corrugation can preferably be designed so that it is just present at maximum deformation of the substrate during use in the scanner unit according to the present invention.

[0021] The base of the sealing element can preferably be made of silicone. Alternatively, the sealing element can be made of another, particularly emission-free, plastic, such as polytetrafluoroethylene (PTFE, also known as Teflon) or fluoroelastomer (FKM). Silicone has proven particularly suitable for this application due to its lower density compared to FKM, resulting in a lower overall weight. Silicone also has advantages over other materials in terms of its hardness, its minimum injectable or pourable material thickness, its rebound resilience, and its overall elastomeric properties.

[0022] The thickness of the substrate is preferably at least 0.2 mm and / or at most 0.8 mm, and may preferably be about 0.6 mm.

[0023] For example, a sealing element according to the invention can be made from silicone by vacuum casting. The sealing element can be translucent, have a Shore A hardness of <50, in particular around 20, a thickness of 0.6 mm, and / or have a mass of >20 g, preferably <2 g, for example around 0.7 g.

[0024] To achieve the underlying object of the present invention, a laser processing head, specifically a laser cutting head, having a scanner assembly is provided according to a third aspect. The scanner assembly includes a scanner unit having a mirror unit, the mirror unit including a scanner mirror and a frame, the mirror unit being movably mounted within the frame. The scanner assembly further includes a partition having a partition opening, the partition being fixed to the frame, the minimum diameter of the partition opening being smaller than the aperture of the scanner mirror. The partition and the mirror unit are axially separated from each other by a gap, the minimum gap width being at most 2 mm, preferably at most 1 mm, and more preferably about 0.8 mm. In this case, axial direction means a direction parallel to the surface normal of the scanner mirror in its rest position or a direction perpendicular to the support surface of the partition.

[0025] The gap is small enough to ensure the necessary freedom of movement for the mirror unit, while making it difficult for particles to escape from the scanner device into the optical space of the laser processing head with which the scanner assembly is integrated. In other words, the partition forms a labyrinth seal with the scanner unit.

[0026] The scanner mirror including the mirror mount and the drive unit can be designed, for example, as described in EP 4000 789 A2, with the magnet pair of the scanner drive preferably being arranged on the mirror mount.

[0027] The scanner assembly may be specifically designed for use with a laser cutting head, and thus for directing a laser beam having a power output of several kilowatts, specifically at least 0.3 kW, preferably at least 4 kW, and even more preferably at least 10 kW.

[0028] To minimize the gap between the partition and the mirror unit, the partition can have a narrow circumferential collar on the side of the partition facing the mirror unit, specifically at the smallest opening diameter of the partition facing the mirror unit, which collar increases the sealing effect of the labyrinth seal.

[0029] The scanner unit can be designed like the scanner unit of the laser processing head according to one of the above-mentioned variations, thereby including a sealing element between the frame and the mirror unit. In this configuration, the partition can additionally function as a beam protector for the sealing element. Therefore, the combination of the sealing element and the partition can improve the service life of the sealing function.

[0030] The scanner assembly may further comprise a cover that can be fixed to a side of the frame opposite the partition and that covers an opening formed by the frame of the scanner unit. The cover preferably protrudes into the frame at the rear of the mirror unit, whereby a gap formed between the cover and the rear of the mirror unit has a minimum gap width of at most 3 mm, preferably at most 0.7 mm. In a configuration with a sealing element, the scanner assembly forms a drive chamber of the scanner unit, in which movable drive components for the mirror unit are arranged, and the drive chamber is limited in the direction of the optical space by the sealing element, laterally by the frame, and at the rear by the cover.

[0031] The cover can be mounted at most 2 mm, preferably at most 1 mm, more preferably at most 0.7 mm laterally from the mirror frame of the scanner unit. The partition and / or cover can each be made of a material with good heat conduction properties, such as a metal or metal alloy. Specifically, the partition and / or cover can be made of steel. In this way, the partition and / or cover can additionally be used as a cooling element for the scanner assembly. Due to the short distance to the mirror unit, heat can be dissipated from the mirror unit, i.e., from the scanner mirror and / or mirror frame, by free or forced convection.

[0032] The bulkhead and / or cover may also be connected to a cooling system, thereby providing active cooling for the scanner assembly. To this end, for example, one or more cooling channels may be disposed in the bulkhead and / or cover, through which a cooling fluid may be circulated.

[0033] Alternatively or additionally, to improve the cooling effect, a cooling gas can be circulated through the gap between the mirror unit and the cover, the volumetric flow rate of which must be selected so that no dynamic pressure is generated in the gap, which would adversely affect the mirror motion.

[0034] The scanner mirror preferably includes a mirror substrate made of a transparent material, specifically quartz glass. In this way, residual transmission of the laser radiation through the scanner mirror, which is unavoidable when the laser beam strikes a reflective surface, can be directed primarily toward the rear of the scanner mirror. This prevents lateral heat dissipation toward the mirror frame and drive unit. The mirror substrate preferably has a thickness-to-diameter ratio of 1:10 or less. This ensures the necessary rigidity of the scanner mirror. For example, the scanner mirror can have a diameter of 25 mm and a thickness of 2.5 mm.

[0035] The scanner mirror may further comprise an oxide interference coating.

[0036] Therefore, the present invention according to its third aspect also has significant advantages over the prior art in terms of cooling: improved cooling reduces the sensitivity of the scanner unit to heating as laser power increases.

[0037] The scanner assembly having the sealing element and the cover can also have a bypass connection with the particle filter to bypass the sealing element. The bypass connection can connect the actuation chamber and the optical space on the other side of the sealing element. The bypass connection ensures pressure equalization between the working space and the optical space, thereby reducing pressure-related resistance that would otherwise complicate the movement of the mirror unit.

[0038] The scanner assembly (see the third aspect of the present invention) or the bulkhead-less scanner unit (see the first aspect of the present invention) can each be arranged to be suspended within the laser processing head. In this context, the suspended arrangement refers to the orientation of the scanner mirror facing downward, i.e., in the direction of gravity. The suspended arrangement of the scanner assembly refers to the preferred working position of the laser processing head, in which the laser beam is directed vertically onto the object to be processed, specifically a metal, plate-like, or tubular workpiece. With regard to particle sealing, the advantages of the present invention are particularly apparent when the scanner assembly is arranged to be in the suspended position.

[0039] MODE FOR CARRYING OUT THE INVENTION The following description of preferred exemplary embodiments, taken in conjunction with the drawings, serves to explain the invention in more detail. [Brief explanation of the drawings]

[0040] [Figure 1] 1 shows a schematic perspective view of a laser cutting system for laser beam cutting. [Figure 2] 1 shows a schematic diagram of a laser cutting head according to the present invention; [Figure 3a] 1 shows a cross-sectional view of a scanner assembly for a laser processing head according to the present invention. [Figure 3b] 3b shows an enlarged detail of the view according to FIG. 3a. [Figure 3c] 3b shows another cross-sectional view of the scanner assembly according to FIG. 3a;

[0041] FIG. 1 illustrates a laser processing system in the form of a laser cutting system 10. The laser cutting system 10 includes a laser beam source 12. The laser beam source 12 may be a CO laser, a solid-state laser, or a diode laser. Although the present illustration shows a CO laser configuration in which the generated laser beam L is directed via a deflection mirror to a laser processing head, here laser cutting head 20, solid-state lasers, specifically disk lasers or fiber lasers, may also generally be preferred as beam sources. In solid-state lasers, the laser beam L is typically conveyed to the laser cutting head 20 by an optical fiber (not shown in FIG. 1) and fed to the laser cutting head 20 via a connecting socket.

[0042] The laser cutting system 10 further comprises a cutting gas supply 14, here in the form of a gas bottle 14, via which cutting gas, which typically contains nitrogen and / or oxygen, is conveyed via a line to the laser processing head 20 and, together with the laser beam L, is directed under pressure through a cutting nozzle onto the workpiece 30 to be processed, here in the form of a plate. The workpiece 30 is mounted on the workpiece support 20 for processing with the processing beam consisting of the laser beam L and the cutting gas jet. Relative movement between the workpiece 30 and the laser cutting head 20 causes local melting of the workpiece 30, which is preferably a metal workpiece 30, and the resulting melt is ejected downwards, thereby forming a cutting gap 32 in the workpiece 30. The laser cutting system 10 further comprises a control device which is programmed to move the cutting head 20 relative to the metal workpiece 30 according to the cutting contour.

[0043] FIG. 2 shows a schematic diagram of a laser cutting head 20 according to the present invention, in which an optical system causes delta folding of the laser beam L. The laser beam L enters the laser cutting head 20 through an entrance opening 21. Preferably, the entrance opening 21 can be designed as a connection socket for a fiber optic cable, through which the laser beam L is transported from a laser beam source to the laser cutting head 20. The diverging laser beam L emerging from the fiber optic cable is collimated by a collimation device, here a collimation lens 22. The collimated laser beam L is then deflected via a deflection unit, here a deflection mirror 23, and directed at a predetermined angle of incidence onto a scanner mirror 242 of a scanner assembly 24, which is suspended and arranged within the laser cutting head 20. The scanner assembly 24 is designed to tilt the scanner mirror 242 about at least two rotation axes with a relatively small movement interval of at most ±2°, preferably at most ±0.3°, relative to the rest or zero position of the scanner mirror 242.

[0044] The scanner assembly 24 includes a partition wall 246 arranged in front of the scanner mirror 242. The laser beam L is deflected at the scanner mirror 242 by an angle α, which is preferably at most 60°, preferably at most 45°, and even more preferably at most 30°, and is directed to the exit opening 28 of the laser cutting head 20. On its way to the exit opening 28, which is preferably designed as a cutting nozzle, the laser beam L can first be widened by a widening device, here a negative lens 25, after which the laser beam L is focused in the direction of the exit opening 28 via a focusing device, here a focusing lens 26, through which it leaves the laser cutting head 20 together with a cutting gas jet (not shown) and is directed as a cutting beam onto the workpiece to be processed.

[0045] By controlled tilting of the scanner mirror 242, the laser beam L can be deflected very quickly in a plane transverse to the exit direction of the laser beam 242 (here the xy plane) at predetermined movement intervals within the exit opening 28, i.e. within the cutting nozzle. The primary feed movement of the cutting beam during the cutting process can thus be superimposed by a relatively small and fast secondary movement of the laser beam L. Through this superimposed secondary pendulum or scanner movement of the laser beam L, the cutting process can be influenced in a targeted manner, for example the cutting gap can be widened in places or the cutting front inclination can be changed.

[0046] The plug socket and / or the collimation lens 22 at the entrance opening 21 of the laser cutting head 20 may be displaceable transversely, i.e. laterally (here in the X direction), relative to the beam path. In addition, the deflection mirror 23 may have a tilt adjustment. This allows the laser beam L to be accurately aligned with the center of the scanner mirror 242. The negative lens 25 may be mounted so as to be displaceable along the beam path (here in the Z direction). By shifting the negative lens 25 in the Z direction, the focal position L of the laser beam L can be adjusted. f can be easily changed.

[0047] A horizontal orientation of the entrance opening 21, as shown in Figure 2, is generally less susceptible to foreign matter than a vertical orientation. The horizontal orientation of the entrance opening 21 also orients the collimation lens 22 so that it is mounted upright within the laser cutting head 20. A vertically oriented collimation lens 22 is also generally less susceptible to foreign matter because the lens surface does not form a deposit for particles within the optical space.

[0048] 3a-3c each show a cross-sectional view of a scanner assembly 24 for a laser processing head according to the present invention. The scanner assembly 24 includes a mirror unit having a scanner mirror 242 and a mirror mount 243. The scanner mirror 242 has a cylindrical shape and is tiltably mounted to the scanner assembly 24 together with a mirror frame 243. For example, the mirror mount 243 can be suspended at four points evenly distributed around its periphery by solid joints in the frame 241 of the scanner assembly 24. The drive unit 244 (shown here with dashed lines) is designed to tilt the mirror mount 243 together with the scanner mirror 242 at high frequency about at least two, preferably orthogonally oriented, rotation axes.

[0049] An annular sealing element 243 made of plastic is disposed between a frame 241, which can be fixed in the laser processing head 20, and the mirror unit 242. The sealing element 243 has a wave-like cross section with a corrugation 2456. The sealing element 245 has a trapezoidal first thickened portion 2452 along its inner periphery, which is mounted in a similarly trapezoidal circumferential groove 2432 provided in the outer periphery of the mirror frame 243. The sealing element 245 has a second thickened portion 2454 along its outer periphery, which is clamped in a circumferential recess 2412 of the frame 241 by a clamp ring 2414. The frame 241, the mirror unit 242, and (optionally) the sealing element 243 together form the scanner unit of the scanner assembly 24.

[0050] Scanner assembly 24 further includes a partition 246 having a partition opening 2462. The partition opening 2462 is surrounded by a funnel-shaped inner wall of partition 246, which preferably has a maximum tilt angle of 30°, preferably 22.5°, and more preferably 15° relative to the surface normal of scanner mirror 242 (when scanner mirror 242 is in its rest position). The minimum opening diameter of partition opening 2462 is smaller than the opening of scanner mirror 242. In this way, mirror mount 243 can be effectively shielded by partition 246 and protected from unwanted irradiation. Partition 246 has a circumferential collar 2464 that extends near scanner mirror 242 and functions as both a particle barrier and a beam shield.

[0051] The cover 248 is disposed on the side of the mirror unit 242 opposite the partition wall 246 and is fixed to the frame 241. Together with the frame 241, the mirror unit 242, and the sealing element 243, the cover 248 defines the actuator or drive chamber of the scanner assembly. The cover 248 is designed as a heat sink 248 and protrudes near the rear of the scanner mirror 242. The partition wall 246 and the heat sink 248 are spaced closely from the scanner mirror 242 and the mirror mount 243, respectively, to ensure their freedom of movement during controlled tilting. At the same time, the distances from the partition wall 246 and the heat sink 248 to the scanner mirror 242 and the mirror frame 243 are kept as small as possible to ensure efficient heat dissipation. For example, movement of the scanner mirror 242 during operation of the scanner assembly 24 can result in a stroke on the outer diameter of the mirror mount 243 of ±80 μm. This relative movement must be taken into account when designing the gap dimensions and when sizing the sealing element 245 in this application.

[0052] To improve heat dissipation from scanner mirror 242 and / or mirror mount 243, bulkhead 246 and heat sink 248 are preferably made of steel or another material with good thermal conductivity properties. Furthermore, bulkhead 246 and heat sink 248 can be actively cooled. The latter promotes the establishment of natural convection in small air gaps. To this end, they can each have one or more cooling channels 247. Cooling channels 247 can be connected to a cooling circuit via cooling fluid connections 249, where a liquid or gaseous cooling fluid flows through the cooling channels and dissipates heat from bulkhead 246 and / or heat sink 248. [Explanation of symbols]

[0053] 10 Laser Cutting System 12 Laser beam source 14 Cutting gas supply unit 16 Workpiece support 20 Laser Cutting Head 21 Inlet opening 22 Collimation Lens 23 Deflecting mirror 24 Scanner Assembly 241 frames 2412 recess 2414 Clamp ring 242 Scanner Mirror 243 Mirror mounting part 2432 Groove 244 Drive Unit 245 Sealing Elements 2452 First thick part 2454 Second thick part 2456 waveform 246 Bulkhead 2462 Bulkhead opening 2464 Circumferential Collar 247 Cooling Channel 248 Cover 249 Cooling fluid connection 25 negative lens 26 Focusing Lens 28 Exit opening 30 workpieces 32 Cutting gap L laser beam L f Laser beam focus α Deflection angle of the scanner mirror

Claims

1. A laser processing head (20) having a scanner unit, the scanner unit comprising: a mirror unit having a scanner mirror (242), the mirror unit having a circumferentially extending groove (2432); a frame (241) that can be fixed in the laser processing head (20), the mirror unit being movably mounted in the frame (241); a ring-shaped elastic sealing element (245) fixed to the frame (241) on an outer periphery of the sealing element and engaging with the circumferentially extending groove (2432) on an inner periphery of the sealing element;

2. The laser processing head (20) of claim 1, wherein the sealing element (245) has a wavy cross section.

3. the circumferentially extending groove (2432) has a cross section that tapers toward the groove base; 3. The laser processing head (20) of claim 1 or 2, wherein the sealing element (245) has a first thickened portion (2452) along the inner circumference of the sealing element (245) that is designed to be complementary in shape to the groove (2432).

4. 4. The laser processing head (20) of claim 3, wherein the first thickened portion (2452) has a width along the inner circumference of the sealing element (245) that is greater than the width of the groove (2432) at the groove base.

5. A laser processing head (20) according to any one of claims 1 to 4, wherein the inner circumference of the sealing element (245) in a relaxed state is smaller than the circumference of the groove (2432) at the groove base, in particular by at least 2% and / or at most 20%.

6. 6. The laser processing head (20) of claim 1, wherein the sealing element (245) is bonded to the mirror unit within the groove (2432) along the inner periphery of the sealing element (245).

7. the sealing element (245) has a second thickened portion (2454) along the periphery of the sealing element (245); 7. The laser processing head (20) according to claim 1, wherein the frame (241) forms a clamping connection with the second thickened portion (2454) of the sealing element (245) along an inner periphery of the frame (241).

8. A sealing element (245) for a scanner unit of a laser processing head (20) according to any one of claims 1 to 7, comprising: an annular base made of an elastic material; A sealing element (245) wherein the base has a first, specifically trapezoidal, thickened portion (2452) along the inner periphery of the base and a second, specifically circular, thickened portion (2454) along the outer periphery of the base.

9. The sealing element (245) of claim 8, wherein the substrate has an undulating cross-section in the relaxed state of the sealing element (245).

10. The sealing element (245) of claim 8 or 9, wherein the substrate is made of silicone.

11. The sealing element (245) according to any one of claims 8 to 10, wherein the thickness of the substrate is at least 0.2 mm and / or at most 0.8 mm, preferably about 0.6 mm.

12. A laser processing head (20) having a scanner assembly (24), the scanner assembly (24) comprising: a scanner unit having a mirror unit comprising a scanner mirror (242) and a frame (241), said mirror unit being movably mounted within said frame (241); a septum (246) having a septum opening (2462); The partition (246) is fixed to the frame (241), the minimum diameter of the partition opening (2462) is smaller than the aperture of the scanner mirror (242); A laser processing head (20) in which the partition (246) and the mirror unit are axially separated from each other by a gap, and the minimum gap width is at most 2 mm, preferably at most 1 mm, specifically about 0.8 mm.

13. The laser processing head (20) according to claim 12, wherein the scanner unit corresponds to the scanner unit of the laser processing head (20) according to any one of claims 1 to 7.

14. a cover (248) that can be fixed to a side of the frame (241) opposite the partition wall (246) and that covers an opening formed by the frame (241) of the scanner unit; 14. A laser processing head (20) according to claim 12 or 13, wherein the cover (248) preferably protrudes into the frame (241) at the rear side of the mirror unit so that a gap formed between the cover (248) and the rear side of the mirror unit has a minimum gap width of at most 3 mm, preferably at most 0.7 mm.

15. The laser processing head (20) according to any one of claims 1 to 7 or any one of claims 12 to 14, wherein the scanner unit or the scanner assembly (24) is arranged suspended within the laser processing head (20).

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