Laser processing head with scanner unit or scanner assembly

Abstract

The invention relates to a laser machining head (20) having a scanner unit, comprising: a mirror unit having a scanner mirror (242), the mirror unit having a channel (2432) running in the circumferential direction; a frame (241) which can be fixed in a machining head (20) of the laser machining system (10), the mirror unit being movably mounted in the frame (241); and an annular resilient sealing element (245) wherein the sealing element (245) is secured to the frame (241) on an outer periphery of the sealing element and is in engagement with the surrounding channel (2432) on an inner periphery of the sealing element. The invention further relates to a sealing element (245) for a scanner unit and to an additional laser machining head having a scanner assembly (24).

Description

Technical Field

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

[0002] Scanner systems for dynamically deflecting a laser beam in a laser processing head by controlled flipping of one or more scanner mirrors are prior art. It is known, for example, to arrange a deflection mirror in the collimated beam guidance region of a laser processing head, which deflection mirror can be flipped independently and dynamically about two transverse axes. This highly integrated design comprises a framed scanner mirror as a rotor assembly, which has four magnet pairs distributed around the periphery, including an iron yoke. The rotor is suspended by four solid articulated arms and is deflected or flipped about an initial position by four coils (stators) correspondingly opposite the magnets. During the movement of the scanner mirror, particles may form, in particular due to wear between the movable parts of the assembly. In order to meet the cleanliness requirements in the laser processing head, which essentially do not allow any adhering contamination in the optical chamber, the semi-clean back space of the scanner assembly must be effectively isolated from the optical chamber 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 supported in a housing, wherein a cover at least partially covers a holder and a base body of the optical element and seals an actuator chamber relative to the optical assembly chamber, and wherein the cover has at least one flexible section to enable the movement of the optical element. The flexible section can be formed by a flexible plastic part. For fastening, the cover can be adhesively bonded to the base body or fixed in a force-locking or form-locking manner, for example clamped with a helical spring or a clamping ring.

[0004] WO 2019145536 A1 describes various variants of how a laser beam can be moved at high frequency and over short distances in a nozzle of a laser processing head, in particular with the aid of a scanner mirror.

[0005] EP 4 000 789 A2 describes an optical device having a carrier and a scanner mirror movably fastened to the carrier. A sealing film forms a gas-tight connection between the scanner mirror and the carrier. Summary of the invention

[0006] The invention has the object of improving the prior art. In particular, effective shielding of the optical chamber of a laser processing head with respect to the actuator chamber or drive chamber of a scanner unit or scanner assembly is provided. Influences on the movement dynamics of the scanner mirrors are to be minimized. In particular, the suitability of existing scanner systems for use in multi-kW laser cutting systems is improved.

[0007] In order to achieve the basic purpose of the present invention, according to a first aspect, a laser processing head, in particular a laser cutting head, having a scanner unit is provided. The scanner unit comprises a reflector unit having a scanner reflector, wherein the reflector unit has a groove that surrounds the circumference. The reflector unit can preferably have a reflector frame arranged on the outer periphery of the scanner reflector. Here, the scanner reflector can preferably be fixedly connected to the reflector frame, for example by bonding. Then, the surrounding groove can preferably be arranged on the outer periphery of the reflector frame.

[0008] Typically, a laser processing head comprises at least one inlet opening for a laser beam, an optical system in which the laser beam is guided through the laser processing head by means of optical elements, in particular by means of lenses and / or mirrors, and an outlet opening for the laser beam to leave the laser processing head. A scanner unit with a scanner mirror as an optical element serving as a beam guide is then arranged adjacent to the optical system of the laser processing head.

[0009] The scanner unit comprises a frame which can be fixed in the laser processing head, wherein the mirror unit is movably mounted in the frame. In particular, the frame and the mirror unit can be arranged in a common plane of the scanner unit, wherein the frame surrounds the mirror unit in a lateral direction. The frame can in particular form a lateral enclosure for the scanner unit.

[0010] Furthermore, the scanner unit comprises an annular, elastic sealing element which is fixed to the frame along its outer periphery and engages with the surrounding channel along its inner periphery. The sealing element is preferably flat.

[0011] The proposed solution enables a particularly compact and lightweight design of the scanner unit in a laser processing head. The sealing element effectively seals the principle-dependent gap between the mirror unit and the frame against the passage of particles. Particles can be generated as a result of relative movements of the mirror suspension and mechanical parts of a drive unit, which is preferably arranged between the frame and the mirror unit and is designed to flip the mirror unit. The sealing element isolates the optical chamber of the laser processing head from the movable drive parts of the scanner unit and thereby increases the safety against optical failures due to contamination. The seal also makes it possible to apply cooling gas to the mirror unit and / or the drive unit on the back side of the scanner unit facing away from the optical chamber. This option is particularly advantageous when the scanner unit is used in multi-kilowatt laser processing systems.

[0012] The scanner mirror together with the mirror frame and the drive unit can be designed, for example, as described in EP 4 000 789 A2, wherein the magnet pairs of the scanner drive are preferably arranged on the mirror frame.

[0013] The sealing element can preferably have a wave-shaped cross section. The wave-shaped cross section can reduce the deformation stiffness of the sealing element, which can also be referred to as a sealing membrane. In this way, the resistance when the mirror unit is turned over can be reduced and the dynamics of the scanner unit can be improved. In particular, the sealing element can have at least one wave in cross section, which wave is designed so that it is still present even when the mirror unit is fully deflected.

[0014] The surrounding channel of the reflector unit can preferably have a cross section that narrows toward the channel bottom. In this case, the channel bottom refers to the deepest point of the channel, that is, in the case of a cylindrical reflector unit, the point at which the channel has its minimum diameter. In particular, the surrounding channel can have a trapezoidal cross section. In addition, the sealing element can have a first thickened portion along the inner periphery of the sealing element, and the first thickened portion is configured to be complementary to the channel in shape. At present, this is particularly to be understood as that the thickened portion is wedge-shaped or trapezoidal, wherein the outer bevel has an inclination that is substantially the same as the inner wall of the channel. The engaging bevel of the thickened portion and the channel ensures an improved form-fitting and adhesive lock of the snap connection between the sealing element and the reflector unit. In addition, the trapezoidal connection shape has been proven to be particularly suitable in terms of the desired mass reduction.

[0015] It can be particularly advantageous if the width of the first thickened portion of the sealing element is greater than the width of the channel at the channel bottom, thereby ensuring that the sealing element engages or snaps into the channel in a snug manner.

[0016] Furthermore, it may be preferred that the inner perimeter of the sealing element in the relaxed state is smaller than the perimeter of the channel at the channel bottom, in particular at least 2% and / or at most 20% smaller. For example, the inner perimeter of the sealing element may be approximately 10% smaller than the perimeter of the channel bottom. In this way, when the sealing element is mounted in the scanner unit, the sealing element is under tension along its inner perimeter and is pressed into the channel.

[0017] The sealing element can also be bonded to the reflector unit along its inner periphery in the channel. For this purpose, in particular, the thickened portion of the sealing element can be wetted with adhesive along the inner periphery when it is inserted into the channel. Such bonding can further improve the adhesion of the sealing element in the channel and thus improve the sealing effect.

[0018] The sealing element can have a second thickening along its outer periphery. The second thickening can be clamped along the inner periphery of the frame. The second thickening can, for example, have a circular cross section. In order to form a clamping connection with the sealing element, the frame can have a surrounding notch along its inner periphery, in which the second thickening can be received and fixed by means of a clamping ring.

[0019] In order to achieve the underlying object of the present invention, according to a second aspect, a sealing element for a scanner unit of a laser processing head according to one of the above-mentioned variants is provided. The sealing element comprises: an annular base body, which is made of an elastic material, wherein the base body has a first thickened portion, which is particularly trapezoidal, along the inner periphery of the base body, and a second thickened portion, which is particularly circular, along the outer periphery of the base body. The shape description of the thickened portion relates to the cross-sectional shape in the circumferential direction of the base body.

[0020] In the relaxed state of the sealing element, the matrix can preferably have a wavy cross section. By forming at least one wave in the matrix of the sealing element, the movement resistance of the reflector unit engaged with the sealing element is reduced. Particularly preferably, the matrix can have at least one wave in the cross section, and the wave has an inner radius of at least 0.5 mm and / or at most 2 mm, preferably about 1 mm to 1.5 mm. The wave can be selectively formed as a protrusion or a depression in the matrix. The wave should be constructed as small as possible in principle to minimize the mass of the matrix. In general, the wave can preferably be designed so that when used in the scanner unit according to the present invention, the wave just still exists when the matrix is ​​maximally deformed.

[0021] The base body of the sealing element can preferably be made of silicone. Alternatively, the sealing element can also be made of other plastics, in particular non-outgassing plastics, such as polytetrafluoroethylene (PTFE, also known as Teflon) or fluororubber (FKM). Due to its lower density compared to FKM and thus its overall lower weight, silicone has proven to be particularly suitable for this application. In addition, silicone also has advantages over other materials in terms of its hardness, its minimum material thickness that can be injected or cast, its anti-collision elasticity and its elastomeric properties.

[0022] The thickness of the base body can preferably be at least 0.2 mm and / or at most 0.8 mm, preferably approximately 0.6 mm.

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

[0024] In order to achieve the fundamental object of the present invention, according to a third aspect, a laser processing head, in particular a laser cutting head, having a scanner assembly is provided. The scanner assembly comprises a scanner unit, which has a mirror unit and a frame, the mirror unit comprising a scanner mirror, wherein the mirror unit is movably supported in the frame. The scanner assembly also comprises a diaphragm having a diaphragm opening, wherein the diaphragm is fixed to the frame, and wherein the minimum diameter of the diaphragm opening is smaller than the aperture of the scanner mirror. The diaphragm and the mirror unit are separated in the axial direction by a gap, wherein the minimum gap width is at most 2 mm, preferably at most 1 mm, and more preferably about 0.8 mm. At present, the axial direction means a direction parallel to the surface normal of the scanner mirror in the equilibrium position (Ruhestellung), or a direction perpendicular to the support plane of the diaphragm.

[0025] The gap ensures the required freedom of movement for the mirror unit and is at the same time small enough that particles have difficulty leaving the scanner device and entering the optical chamber of the laser processing head in which the scanner assembly is integrated. In other words, the aperture forms a labyrinth seal with the scanner unit.

[0026] The scanner mirror and the drive unit together with the mirror frame can be designed, for example, as described in EP 4 000 789 A2, wherein the magnet pairs of the scanner drive are preferably arranged on the mirror frame.

[0027] The scanner assembly may in particular be designed for use in a laser cutting head and therefore for guiding a laser beam having a power of several kW, in particular at least 0.3 kW, preferably at least 4 kW, even more preferably at least 10 kW.

[0028] In order to minimize the gap between the aperture and the reflector unit, the aperture can have a narrow circumferential flange pointing in the direction of the reflector unit on the side of the aperture facing the reflector unit, especially at the smallest opening diameter of the aperture. The flange enhances the sealing effect of the labyrinth seal.

[0029] The scanner unit can in particular be designed similarly to a scanner unit of a laser processing head according to one of the above-described variants and thus have a sealing element between the frame and the mirror unit. According to this configuration, the diaphragm can additionally serve as a beam guard for the sealing element. The combination of sealing element and diaphragm thus increases the service life of the sealing function.

[0030] The scanner assembly can also include a cover, which can be fixed to the side of the frame opposite the aperture and covers the opening formed by the frame of the scanner unit. The cover can preferably extend into the frame at the rear side of the mirror unit so that the gap formed between the cover and the rear side of the mirror unit has a minimum gap width of at most 3 mm, preferably at most 0.7 mm. In the configuration with the 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 which is bounded in the direction of the optical chamber by the sealing element, laterally by the frame and at the rear by the cover.

[0031] The cover can be located laterally close to the mirror frame of the scanner unit by up to 2 mm, preferably up to 1 mm, more preferably up to 0.7 mm. The aperture and / or the cover can each be made of a material with good heat conduction properties, for example a metal or a metal alloy. In particular, the aperture and / or the cover can be made of steel. In this way, the aperture and / or the cover can additionally serve as a cooling element for the scanner assembly. Due to the small distance to the mirror unit, heat can be conducted away from the mirror unit, i.e. from the scanner mirror and / or the mirror frame, by natural or forced convection.

[0032] The aperture and / or the cover can also be connected to a cooling system and thereby provide active cooling for the scanner assembly.For this purpose, for example one or more cooling channels can be arranged in the aperture and / or the cover in which a cooling fluid can circulate.

[0033] Alternatively or additionally, cooling gas can be circulated through the gap between the reflector unit and the cover to improve the cooling effect. Here, the volume flow of the cooling gas must be selected so that no stagnation pressure is generated in the gap that would negatively influence the movement of the reflector.

[0034] The scanner mirror can preferably include a mirror substrate made of a transparent material, in particular quartz glass. In this way, the residual transmission of laser radiation through the scanner mirror that is inevitable when the laser beam strikes the reflective surface can be conducted in an appropriate manner, in particular, toward the back of the scanner mirror. This can prevent lateral heat dissipation toward the mirror frame and the drive unit. The mirror substrate preferably has a thickness to diameter ratio of at most 1:10. This can ensure 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 also include an oxidized interference coating.

[0036] Therefore, the invention according to the third aspect also has significant advantages over the prior art in terms of cooling.The improved cooling reduces the sensitivity of the scanner unit to heating up when the laser power is increased.

[0037] The scanner assembly with the sealing element and the cover can also have a bypass connection with a particle filter for bridging the sealing element. The bypass connection can connect the driver chamber and the optical chamber on the other side of the sealing element. The bypass connection ensures pressure equalization between the working chamber and the optical chamber and thus reduces the pressure-dependent resistance that would otherwise make it difficult for the mirror unit to move.

[0038] The scanner assembly (see the third aspect of the invention) or the scanner unit without an aperture (see the first aspect of the invention) can each be arranged suspended in the laser processing head. In this context, the suspended arrangement describes the orientation of the scanner mirror downwards or in the direction of gravity. The suspended arrangement of the scanner assembly relates to a preferred working position of the laser processing head, in which the laser beam is directed vertically onto the object to be processed, in particular a metallic, plate-shaped or tubular workpiece. The advantages of the invention with regard to particle sealing are particularly evident when the scanner assembly is arranged suspended. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The following description of preferred embodiments is used to explain the present invention in more detail with reference to the accompanying drawings.

[0040] In the attached picture:

[0041] Figure 1 A laser cutting system for laser beam cutting is shown in schematic perspective view;

[0042] Figure 2 A schematic diagram of a laser cutting head according to the present invention is shown;

[0043] Figure 3a shows a cross-sectional view of a scanner assembly for a laser processing head according to the present invention;

[0044] Figure 3b Shown according to Figure 3a an enlarged detail of the illustration; and

[0045] Figure 3c Shown according to Figure 3a Another cross-sectional view of a scanner assembly. DETAILED DESCRIPTION

[0046] Figure 1 A laser processing system in the form of a laser cutting system 10 is shown. The laser cutting system 10 comprises a laser beam source 12. The laser beam source 12 can be a CO2 laser, a solid-state laser or a diode laser. Although the current illustration shows a CO2 laser configuration in which the generated laser beam L is guided via a deflection mirror to a laser processing head, here a laser cutting head 20, a solid-state laser, in particular a disk laser or a fiber laser, can in principle also be preferred as a beam source. In a solid-state laser, the laser beam L is usually directed by means of an optical fiber ( Figure 1 ) is transmitted to the laser cutting head 20 and fed into the laser cutting head 20 via the connecting socket.

[0047] The laser cutting system 10 further comprises a cutting gas supply 14, here in the form of a gas cylinder 14, via which a cutting gas, which usually contains nitrogen and / or oxygen, is supplied via a line to a laser processing head 20 and directed together with a laser beam L at a predetermined pressure through a cutting nozzle to a workpiece 30 to be processed, in this case a plate-shaped workpiece. The workpiece 30 is supported on a workpiece support 20 for processing by a processing beam consisting of a laser beam L and a cutting gas beam. The workpiece 30, preferably a metal workpiece 30, is melted locally by the relative movement between the workpiece 30 and the laser cutting head 20, and the formed melt is discharged downwards, so that a slit 32 is formed 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 workpiece 30 in accordance with the cutting contour.

[0048] Figure 2A laser cutting head 20 according to the invention is schematically shown, in which an optical tool causes a delta folding of a laser beam L. The laser beam L enters the laser cutting head 20 through an inlet opening 21. Preferably, the inlet opening 21 can be designed as a connection socket for an optical fiber cable, via which the laser beam L is transmitted from a laser beam source to the laser cutting head 20. The divergent laser beam L emitted from the optical fiber cable is collimated by means of a collimating device, here a collimating lens 22. Then, the collimated laser beam L is deflected via a deflection unit, here a deflection mirror 23, so that the laser beam is directed to a scanner mirror 242 of a scanner assembly 24 at a predefined angle of incidence, which is suspended in the laser cutting head 20. The scanner assembly 24 is designed to flip the scanner mirror 242 relative to the equilibrium position or zero position of the scanner mirror 242 around at least two rotation axes in a relatively small range of motion of up to ±2°, preferably up to ±0.3°.

[0049] The scanner assembly 24 comprises an aperture 246 arranged in front of the scanner reflector 242. The laser beam L is deflected at an angle α at the scanner reflector 242 and directed to the outlet opening 28 of the laser cutting head 20, the angle being preferably at most 60°, preferably at most 45°, and even more preferably at most 30°. On the way to the outlet 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, and then focused in the direction of the outlet opening 28 via a focusing device, here a focusing lens 26, through which the laser beam leaves the laser cutting head 20 together with a cutting gas beam (not shown) and is directed as a cutting beam onto the workpiece to be processed.

[0050] By controlled tilting of the scanner mirror 242, the laser beam L can be deflected very quickly within a predetermined movement range in the outlet opening 28, i.e., in the cutting nozzle, in a plane (here, the xy plane) transverse to the emission direction of the laser beam 242. In other words, the main feed movement of the cutting beam during the cutting process can be superimposed by a relatively small and rapid secondary movement of the laser beam L. By means of this superimposed secondary oscillating movement or scanning movement of the laser beam L, the cutting process can be influenced in a targeted manner, for example, the cutting slit can be widened at certain locations or the inclination of the cutting front can be changed.

[0051] The plug socket and / or the collimating lens 22 at the inlet opening 21 of the laser cutting head 20 can be displaceable transversely to the beam path, i.e. transversely (here in the X direction). In addition, the deflection mirror 23 can have a tilt adjustment function. This allows the laser beam L to be accurately aligned with the center of the scanner mirror 242. The negative lens 25 can be supported displaceably along the beam path (here in the Z direction). By displacing the negative lens 25 in the Z direction, the focal position L of the laser beam L can be easily changed. f .

[0052] The inlet opening 21 is pressed Figure 2 The horizontal arrangement shown in the figure is generally less susceptible to contamination than the vertical arrangement. In addition, due to the horizontal arrangement of the inlet opening 21, the collimating lens 22 is oriented to be supported upright in the laser cutting head 20. Likewise, the upright collimating lens 22 is generally less susceptible to contamination because the lens surface does not form a deposition portion for particles in the optical chamber.

[0053] Figure 3a to Figure 3c A scanner assembly 24 for a laser machining head according to the invention is shown in each case in a cross-sectional view. The scanner assembly 24 comprises a mirror unit having a scanner mirror 242 and a mirror frame 243. The scanner mirror 242 has a cylindrical shape and is supported in the scanner assembly 24 in a flippable manner together with the mirror frame 243. For example, the mirror frame 243 can be suspended in the frame 241 of the scanner assembly 24 by solid joints at four locations evenly distributed on its circumference. The drive unit 244 (indicated here by a dashed line) is designed to flip the mirror frame 243 together with the scanner mirror 242 at a high frequency about at least two rotation axes, which are preferably oriented perpendicular to each other.

[0054] An annular sealing element 243 made of plastic is arranged between a frame 241 that can be fixed in the laser processing head 20 and a reflector unit 242. The sealing element 243 has a wave-shaped cross section with waves 2456. Along the inner periphery of the sealing element 245, the sealing element has a first trapezoidal thickening 2452, which is supported in a likewise trapezoidal, circumferential groove 2432 on the outer periphery of the reflector frame 243. Along the outer periphery of the sealing element 245, the sealing element has a second thickening 2454, which is clamped in a circumferential notch 2412 of the frame 241 by means of a clamping ring 2414. The frame 241, the reflector unit 242 and the (optional) sealing element 243 together form a scanner unit of the scanner assembly 24.

[0055] The scanner assembly 24 further comprises an aperture 246 having an aperture opening 2462. The aperture opening 2462 is surrounded by a funnel-shaped inner wall of the aperture 246, wherein the inner wall preferably has a maximum inclination angle of 30°, preferably 22.5°, more preferably 15° relative to the surface normal of the scanner mirror 242 (in the equilibrium position of the scanner mirror 242). The minimum opening diameter of the aperture opening 2462 is smaller than the aperture of the scanner mirror 242. In this way, the mirror frame 243 can be effectively shielded by the aperture 246 and protected from unwanted radiation. The aperture 246 has a surrounding flange 2464, which is close to the scanner mirror 242 and serves as both a particle barrier and a beam guard.

[0056] A cover 248 is arranged on the side of the mirror unit 242 opposite to the aperture 246 and is fixed to the frame 241. The cover 248, together with the frame 241, the mirror unit 242 and the sealing element 243, defines an actuator chamber or a drive chamber of the scanner assembly. The cover 248 is currently designed as a heat sink 248 and protrudes close to the back of the scanner mirror 242. The aperture 246 and the heat sink 248 are each separated from the scanner mirror 242 and the mirror frame 243 by a narrow gap to ensure the freedom of movement of the scanner mirror and the mirror frame during the controlled flipping. At the same time, the distance of the aperture 246 and the heat sink 248 to the scanner mirror 242 and the mirror frame 243 is kept as small as possible to ensure effective heat removal. For example, during the operation of the scanner assembly 24, the movement of the scanner mirror 242 can result in a travel of ±80 μm at the outer diameter of the mirror frame 243. In this application, this relative movement must be taken into account accordingly when dimensioning the gap and also when dimensioning the sealing element 245 .

[0057] In order to improve the heat removal from the scanner mirror 242 and / or the mirror frame 243, the aperture 246 and the heat sink 248 are preferably made of steel or other materials with good thermal conductivity properties. In addition, the aperture 246 and the heat sink 248 can be actively cooled. The latter is conducive to the formation of natural convection in small air gaps. For this purpose, the aperture and the heat sink can each have one or more cooling channels 247. The cooling channel 247 can be connected to a cooling circuit via a cooling fluid connector 249, in which a liquid or gaseous cooling fluid flows through the cooling channel and removes heat from the aperture 246 and / or the heat sink 248.

[0058] Reference numerals list

[0059] 10 Laser cutting system

[0060] 12 Laser beam source

[0061] 14 Cutting gas supply

[0062] 16 Workpiece support

[0063] 20 Laser cutting head

[0064] 21 Entrance opening

[0065] 22 Collimating lens

[0066] 23 Deflecting mirror

[0067] 24 Scanner Components

[0068] 241 Framework

[0069] 2412 Notch

[0070] 2414 Clamp Ring

[0071] 242 Scanner reflector

[0072] 243 Mirror frame

[0073] 2432 Channel

[0074] 244 Drive Unit

[0075] 245 Sealing element

[0076] 2452 First thickening part

[0077] 2454 Second thickening part

[0078] 2456 Wave

[0079] 246 Aperture

[0080] 2462 Aperture opening

[0081] 2464 Surrounding flange

[0082] 247 Cooling Channel

[0083] 248 Covering

[0084] 249 Cooling fluid connector

[0085] 25 Negative lens

[0086] 26 Focusing lens

[0087] 28 Exit opening

[0088] 30 Workpieces

[0089] 32 Cutting the gap

[0090] L Laser beam

[0091] L f Laser beam focus

[0092] α Deflection angle at the scanner mirror

Claims

1. A laser processing head (20) having a scanner unit, the scanner unit comprising: A reflector unit having a scanner reflector (242), wherein the reflector unit has a groove (2432) surrounding in a circumferential direction; a frame (241) which can be fixed in the laser processing head (20), wherein the mirror unit is movably supported in the frame (241); and An annular, elastic sealing element (245), wherein the sealing element (245) is fixed to the frame (241) on the outer periphery of the sealing element and is in engagement with the surrounding channel (2432) on the inner periphery of the sealing element.

2. The laser processing head (20) according to claim 1, in, The sealing element (245) has a wave-shaped cross section.

3. The laser processing head (20) according to claim 1 or 2, in, The surrounding channel (2432) has a cross-section that narrows toward the channel bottom, and The sealing element (245) has a first thickened portion (2452) along the inner periphery of the sealing element, and the first thickened portion is designed to be complementary in shape to the groove (2432).

4. The laser processing head (20) according to claim 3, in, The first thickened portion (2452) has a width along the inner periphery of the sealing element (245) that is greater than the width of the channel (2432) at the channel bottom.

5. The laser processing head (20) according to one of the preceding claims, in, The inner circumference of the sealing element (245) in the relaxed state is smaller than the circumference of the channel (2432) at the channel bottom, in particular, smaller by at least 2% and / or at most 20%.

6. The laser processing head (20) according to one of the preceding claims, in, The sealing element (245) is bonded to the reflector unit in the groove (2432) along the inner periphery of the sealing element.

7. The laser processing head (20) according to one of the preceding claims, in, The sealing element (245) has a second thickened portion (2454) along the outer periphery of the sealing element, and The frame (241) forms a clamping connection with the second thickened portion (2454) of the sealing element (245) along the inner periphery of the frame.

8. A sealing element (245) for a scanner unit of a laser machining head (20) according to one of the preceding claims, the sealing element (245) comprising: an annular base body made of elastic material, The base body has a first thickened portion (2452) along the inner periphery of the base body, and a second thickened portion (2454) along the outer periphery of the base body, wherein the first thickened portion is particularly trapezoidal and the second thickened portion is particularly circular.

9. The sealing element (245) according to claim 8, in, In the relaxed state of the sealing element (245), the base body has a wave-shaped cross section.

10. The sealing element (245) according to claim 8 or 9, in, The matrix consists of silicone.

11. The sealing element (245) according to one of claims 8 to 10, in, The thickness of the base body 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 and a frame (241), the mirror unit comprising a scanner mirror (242), wherein the mirror unit is movably mounted in the frame (241); and an aperture (246) having an aperture opening (2462), Wherein, the aperture (246) is fixed to the frame (241), wherein the minimum diameter of the aperture opening (2462) is smaller than the aperture of the scanner reflector (242), and The aperture (246) and the mirror unit are spaced apart from one another in the axial direction by a gap, wherein the minimum gap width is at most 2 mm, preferably at most 1 mm, in particular approximately 0.8 mm.

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

14. The laser processing head (20) according to claim 12 or 13, further comprising: a cover portion (248) which can be fixed on a side of the frame (241) opposite to the aperture (246) and covers an opening formed by the frame (241) of the scanner unit, The cover portion (248) preferably extends into the frame (241) on the back side of the reflector unit, so that a gap formed between the cover portion (248) and the back side of the reflector 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 one of claims 1 to 7 or one of claims 12 to 14, in, The scanner unit or the scanner assembly (24) is arranged suspended in the laser processing head (20).

Images