MOUNTING AND SEALING METHOD FOR OPTICAL ELEMENTS AND LASER PROCESSING HEAD

Abstract

The present disclosure relates to a holder and a method for using an optical element, wherein the holder comprises a drawer consisting of a base plate with an opening above which a receptacle is arranged in which an optical element is arranged, wherein a seal is arranged between a lower edge of the optical element and an inner lower end of the opening of the base plate of the drawer, and a pressure ring is arranged around the receptacle, the pressure ring having at least one projection on its underside which engages in at least one recess on the top of the base plate, the bottom of the at least one recess having a ramp with a seamlessly changing height with respect to an underside of the base plate. A further subject matter of the present disclosure relates to a laser processing head for laser material processing comprising at least one holder as previously described.the use of a suitable holder in a laser processing head.

Description

Territory of Revelation

[0001] The present disclosure relates generally to a seal for optical elements. Brief description of the state of the art

[0002] COHERENT ® The company develops and manufactures lasers, laser processing heads and systems, components and accessories, as well as laser measuring instruments. The laser processing heads and systems are designed for processing materials, including welding, soldering, and cutting.

[0003] Laser processing heads and systems comprise a variety of optical elements. For beam shaping, laser processing systems use lenses, for example, which collimate or focus the laser beam. The optical elements are usually arranged in groups along the optical axis and are assembled in so-called tubes. Often, entire groups of optical elements can be replaced as needed, eliminating the need to replace numerous individual elements.

[0004] Welding and cutting of workpieces generates emissions that can accumulate in the vicinity of the processing point. These deposits can impair the function of laser optics by forming deposits on the optical surfaces. These deposits not only reduce the performance of the optical systems but can also damage or even destroy the laser optics. Furthermore, in laser processing heads, it may be necessary for optical elements to be pressure-tight on at least one side, as high pressure is present on one side of the optical element. For this reason, the optical elements of such devices are pressure-tight on one side.

[0005] Laser processing heads for laser applications with a wavelength of 1 µm typically consist of one or more lenses and one or more protective glass panels to prevent lens contamination. This may be necessary, for example, in laser cutting heads where the pressure below the last protective glass panel can reach 20 bar or more. Even small leakage rates from this seal can lead to gradual contamination of lenses and other optical elements, as the cutting gas may contain oil, water, or other contaminants, or process gases could enter this area at low pressures.

[0006] At the same time, optical elements such as protective glasses or lenses should be replaceable by the operator without significant time or effort. This replacement is usually achieved by arranging the optical elements in pull-out drawers.

[0007] Drawers with a spring-loaded seal, at least on the side subjected to pressure, are known from the prior art. The spring is usually made of stainless steel, and the seal material is PTFE or another abrasion-resistant plastic. An additional sliding ring is often present on the side opposite the pressure to prevent direct metal-on-metal sliding. When the drawer is inserted into its holder, the spring-loaded seal slides over the sealing surface. To ensure this sliding action, both the seal and the sealing surface must be smooth and possess a certain minimum hardness. However, the required minimum hardness of the seal can compromise a good seal or a low leakage rate.

[0008] Pressure relief valves are used, for example, to reduce a gradual pressure increase on the optical elements above the protective glass. However, this does not prevent the gradual contamination of the optical elements above the protective glass. Instead, a constant flow of contaminated gas is created through the optical chamber.

[0009] Published US patent application US 2022 / 0219264 A1 describes a laser irradiation head comprising a lower housing with a through-hole, a holder, and a first protective glass held by the holder. The lower housing has a holder insertion opening. The lower housing has a top surface in which the through-hole is open. The holder has a holder top surface. The laser irradiation head includes a sealing element that is received in a groove and a piston that elastically preloads the holder. Assuming a groove cross-section located at the furthest end in an insertion direction of the holder, the piston preloads the holder after the groove cross-section has passed an opening face of the through-hole in the top surface when the holder is installed.

[0010] German patent DE 102015 107 556 B3 discloses a cassette module for holding an optical element in a laser processing system, in particular a laser processing head for processing a workpiece with a laser beam, comprising a housing that has a receiving shaft for receiving the optical element or protective glass and an opening on two opposite sides for the passage of a beam path guided through the laser processing system, and a cassette in which the optical element is held and which can be inserted into the receiving shaft for positioning the optical element in the beam path. To largely prevent abrasion when changing the optical element or protective glass, the cassette is provided with at least two opposing contact surfaces for contact with corresponding walls of the receiving shaft, which converge in the insertion direction.

[0011] The use of soft seals, such as O-rings, often leads to them sticking together during operation, preventing the drawer from being pulled out.

[0012] The purpose of this disclosure is to provide a holder for an optical element that allows for quick replacement of the optical element. Furthermore, the holder has a pressure-tight seal on one side. Summary of Revelation

[0013] The present disclosure provides a holder for an optical element, comprising a drawer consisting of a base plate with an opening above which a receptacle is arranged in which an optical element is arranged, wherein a seal is arranged between a lower edge of the optical element and an inner lower end of the opening of the base plate of the drawer, and a pressure ring is arranged around the receptacle, the pressure ring having at least a projection on its underside which engages in at least one recess on the top of the base plate, wherein the bottom of the at least one recess has a ramp with a seamlessly changing height with respect to an underside of the base plate.

[0014] According to the invention, in one embodiment it is provided that the pressure ring is arranged to rotate around the receptacle.

[0015] Furthermore, it is provided that the pressure ring has a lever extending radially outwards.

[0016] In one embodiment of the bracket, the base plate of the drawer has a connecting element on one side.

[0017] Another aspect of the disclosure concerns the mounting, in which the drawer with optical element, pressure ring and seal is arranged in a housing.

[0018] It is also provided that the housing has an opening above and below the optical element.

[0019] In another embodiment of the bracket, the housing has a lateral opening through which a drawer with optical element, pressure ring and seal can be inserted into the housing.

[0020] In one embodiment, the bracket includes a drawer which is connected to a side cover of the housing via the connecting element.

[0021] In one embodiment, the side cover of the housing of a bracket and an end of the at least one recess in the base plate of the drawer fix the lever of the pressure ring in a position.

[0022] It is also planned that the side cover of the housing will be secured by a locking mechanism.

[0023] In a holder according to the present disclosure, the optical element comprises lenses, protective glasses, mirrors and beam shaping elements.

[0024] Another subject of the present disclosure is a method for sealing an optical element, comprising the steps a. Arrangement of an optical element in a holder according to claim 1; b. Inserting the drawer through a side opening into a housing which has an opening above and below the optical element in the inserted drawer; c. Rotating the pressure ring via a radially outward extending lever of the pressure ring and thus raising the pressure ring by sliding the at least one projection on the underside of the pressure ring in the at least one recess on the top side of the base plate over the ramp in the at least one recess with a seamlessly changing height; d. Clamping the pressure ring against the inner top of the housing; e. Sealing the lower opening of the housing by squeezing the gasket between a lower edge of the optical element and an inner lower top of the housing.

[0025] In one embodiment, the method includes the further step of arranging the housing in a laser material processing head.

[0026] Another subject of the present disclosure relates to a laser processing head for laser material processing comprising at least one holder as previously described, or the use of a corresponding holder in a laser processing head.

[0027] Further aspects, features, and advantages of the present disclosure will readily become apparent from the following detailed description, which simply presents preferred embodiments and implementations. The present disclosure can also be realized in other and different embodiments, and its various details can be modified in various obvious aspects without departing from the teaching and scope of the present disclosure. Accordingly, the drawings and descriptions are to be regarded as illustrative and not as limiting. Additional tasks and advantages of the disclosure are partly set forth in the following description and partly become apparent from the description or can be derived from the execution of the disclosure. Brief description of the characters

[0028] The disclosure is further illustrated below with reference to the figures. It is obvious to the person skilled in the art that these are only possible, exemplary embodiments, without limiting the disclosure to the embodiments shown, wherein: Fig. Figure 1 shows a drawer with the associated components in an exploded view. Fig. 2 shows the elements from Fig. 1 in the assembled state with the pressure ring in a lower position. Fig. 3 shows the elements from Fig. 1 in the assembled state with the pressure ring in an upper position. Fig. 4 shows in a cross-sectional drawing the arrangement of the elements from the Fig. 1-3 in a housing in a relaxed state, with the pressure ring in a lower position. Fig. 5. shows in a cross-sectional drawing the arrangement of the elements from the Fig. 1-3 in a housing in a locked state, with the pressure ring in an upper position. Fig. Figure 6 shows a perspective view of the drawer with the lid closed. Fig. Figure 7 shows a top view of the drawer 20 with the lid 80 closed and secured by the locking mechanism 81. Lever 51 cannot be moved due to the closed lid, thus locking pressure ring 5 against rotation around guide 21. Fig. Figure 8 shows a laser processing head in which a housing with a drawer, as previously described, is arranged. Detailed description of the revelation

[0029] The previously formulated objective of the disclosure is achieved by the features of the independent claims. The dependent claims cover further specific embodiments of the disclosure.

[0030] For the purposes of this disclosure, optical elements shall be understood to mean lenses, protective glasses, mirrors, and beam-shaping elements. The term "fixation" in connection with an optical element encompasses the centering and positioning of the optical element in the beam path.

[0031] The present disclosure provides a drawer for receiving optical elements which, when inserted, can be expanded so that a seal on one side of the optical element is pressed against the sealing surface. The expansion is achieved by rotating a pressure ring along several ramps arranged circularly within the drawer. Expansion within the drawer can also be achieved by other means such as wedges, threads, or the like.

[0032] Accidental release of the pressure built up by the rotation is prevented by the closed drawer lid, as this prevents it from turning backwards. To pull out the drawer, the lid is opened again, releasing the drawer, which can then be pulled out. If the seal adheres to the sealing surface, the necessary force can be applied to the protective glass via a positive fit to break this adhesion. This positive fit is achieved by manufacturing the seal as a molded part from elastomers such as NBR (nitrile butadiene rubber), SBR (styrene butadiene rubber), EPDM (ethylene propylene diene monomer; M-group), FPM and FKM (fluorocarbon rubber), or HNBR (hydrogenated acrylonitrile butadiene rubber).

[0033] Fig. Figure 1 shows an exploded view of a drawer with its associated components. Pressure ring 5 has a lever 51 on one side, which projects radially from the outer edge of the pressure ring 5. Lever 51 can be used to rotate the pressure ring 5 circularly around its center point. During rotation, the pressure ring is turned around the circular guide 21 of the drawer 20. On its underside, pressure ring 5 has at least one projection 52, which is arranged on the ramps 23 of the drawer 20. The ramps 23 are located in the Fig. 1 embodiment shown arranged in recesses or slots 24.

[0034] The optical element 30 is arranged in the guide 21. The lower edge of the optical element 30 is surrounded by the seal 40.

[0035] Fig. 2 shows the elements from Fig. 1 in the assembled state with the pressure ring in a lower position. Pressure ring 5 surrounds guide 21 of the drawer 20. The optical element 30 is arranged in guide 21. The seal arranged at the lower edge of the optical element 30 is in Fig. 2 not visible.

[0036] At the in Fig. In the embodiment shown in Figure 2, lever 51 is arranged on the right side of connecting element 22. The connecting element 22 serves to connect and fix the drawer 20 to a device in which the drawer 20 is arranged.

[0037] In Fig. Figure 2 shows that there is no gap between pressure ring 5 and drawer 20. The at least one protrusion (not visible) on the underside of pressure ring 5 is located in the recesses 24 at the lowest point of the at least one ramp (not visible). Pressure ring 5 is therefore in a lower position.

[0038] Fig. 3 shows the elements from Fig. 1 in the assembled state with the pressure ring 5 in an upper position. Lever 51 is located in Fig. 3 on the left side of connecting element 22. The changed position is based on a rotation of pressure ring 5 around guide 21 of the drawer 20. To carry out this rotation, the pressure ring 5 can be moved by means of lever 51.

[0039] The protrusion 52, at least one of which is a projection, moves within the circular recesses 24 and slides upwards on ramp 23, causing pressure ring 5 to also move upwards or lift. A gap 15 is created between drawer 20 and pressure ring 5 by its upward movement.

[0040] Now that the interaction between pressure ring 5 and drawer 20 has been described, it shows Fig. 4 in a sectional drawing the arrangement of the elements from the previous figures in a housing 60 in a relaxed state, in which the pressure ring 5 is in a lower position in the drawer 20.

[0041] On the left side of the optical element 30, it can be seen that the projection 52 is in contact with the lower end 231 of ramp 23 (not visible) in recess 24. Projection 52 is thus located at the lower end of the ramp (not visible). On the right side of the optical element 30, a gap can be seen between the upper end 232 of the ramp (not visible) and the lower side 54 of the pressure ring 5. Projection 52 at the lower end of pressure ring 5 is obscured on the right side.

[0042] Since in Fig. 4. Since the upper edge 53 of pressure ring 5 does not rise above the upper edge 25 of the drawer 20, no pressure is exerted on seal 40. A gap exists between the inner top surface 61 of the housing 60 and the upper edge 53 of pressure ring 5. For this reason, the Fig. The state shown in point 4 is also referred to as the relaxed state.

[0043] Fig. 5. shows in a cross-sectional drawing the arrangement of the elements from the Fig. 1-3 in a housing 60 in a tensioned state, in which the pressure ring 5 is in an upper position and thus pressure is exerted on seal 40, thereby ensuring the sealing of the optical element 30 against the inner underside 62 of the housing 60.

[0044] On the left side of the optical element 30, it is clearly visible that the upper edge 53 of pressure ring 5 rises above the upper edge 25 of drawer 25. The upper edge 53 of pressure ring 5 comes into contact with the inner top surface 61 of housing 60, which pushes the drawer 20 downwards and thus compresses the seal 40 between the optical element 30 and the inner bottom surface 62 of housing 60. This seals the lower opening 63 of housing 60.

[0045] In Fig. On the left side of the optical element 30, a gap can be seen between the underside 54 of pressure ring 5 and the lower end 231 of ramp 23 (not visible) in recess 24. On this side, the projection of the pressure ring on the drawer ramp has been turned upwards, as can be seen on the right side of the optical element.

[0046] Fig. Figure 5 shows on the right side of the optical element 30 that the upper end 232 of the ramp (not visible) is in contact with overhang 52.

[0047] Fig. Figure 6 shows a perspective view of the drawer 20 with the lid 80 closed and secured by the locking mechanism 81. The pressure ring 5 cannot be rotated around the guide 21 by means of the lever 51, as the lid 80 prevents counterclockwise rotation. Further clockwise rotation is not possible because the projection 52 at the end of recess 24 abuts the upper end of ramp 23 (not shown). The pressure ring is thus locked, and movement in the tensioned state is not possible as long as the lid 80 closes the housing (not shown).

[0048] Fig. Figure 7 shows a top view of the drawer with the lid closed and locked in place.

[0049] Fig. Figure 8 shows a laser material processing head 100 in which a housing 60 with an optical element 30, as previously described, is arranged. On the left side, the laser beam 110 enters the laser material processing head 100, for example via a fiber 105, and is shaped by further optical elements 30. On the right side of the laser material processing head 100, the laser spot position 115, with which the material processing is carried out, can be seen. The in Fig. The embodiment shown in Figure 8 also shows a lens drive 120 and a cutting device 125.

[0050] As a technical effect, the features of the present disclosure result in the fact that a holder for an optical element can be clamped in a housing with minimal design effort in such a way that the optical element is sealed on one side against the space behind it by a seal.

[0051] An advantage of a device according to the present disclosure is the minimal design effort required. Furthermore, it is advantageous that the tensioned pressure ring (in the upper position) is secured within the housing against rotation back into the relaxed (lower position) position by the housing cover. The drawer can be easily removed from a laser processing head, allowing the optical element to be easily removed from the housing or drawer and, for example, replaced.

[0052] Due to the design of the holder, drawer and housing, the position of the optical element in the holder or housing in the device is clearly defined, which is why after a change of an optical element no check of the position of the optical element or even a calibration of the device (laser processing head) is required.

[0053] Further aspects, features, and advantages of the present disclosure will readily become apparent from the following detailed description, which simply presents preferred embodiments and implementations. The present disclosure can also be realized in other and different embodiments, and its various details can be modified in various obvious aspects without departing from the teaching and scope of the present disclosure. Accordingly, the drawings and descriptions are to be regarded as illustrative and not as limiting. Additional tasks and advantages of the disclosure are partly set forth in the following description and partly become apparent from the description or can be derived from the execution of the disclosure. Reference sign 5 pressure ring 51 levers 52 Overhang 53 Top edge of pressure ring 54 Lower edge of pressure ring 15 columns 20 drawers 21 Leadership 22 Connecting element 23 Ramp 231 lower end of ramp 232 upper end of ramp 24 In-depth study 25 Top edge of drawer 30 optical element 40 Seal 60 cases 61 inner top 62 inner underside 63 lower opening 70 contacts 80 lids 81 Locking mechanism 100 laser material processing head 105 fiber 110 laser beam 115 Laser spot position 120 lens drive 125 cutting device

Claims

[1] A holder for an optical element (30) comprising a drawer (20) consisting of a base plate with an opening above which a receptacle is arranged in which an optical element (30) is arranged, wherein a seal (40) is arranged between a lower edge of the optical element (30) and an inner lower end of the opening of the base plate of the drawer (20) and a pressure ring (5) is arranged around the receptacle, which has at least a projection (52) on its underside which engages in at least one recess on the top of the base plate, wherein the bottom of the at least one recess has a ramp (23) with a seamlessly changing height with respect to an underside of the base plate. [2] The holder according to claim 1, wherein the pressure ring (5) is arranged to rotate about the receptacle [3] The holder according to one of claims 1 or 2, wherein the pressure ring (5) has a radially outward extending lever (51). [4] The holder according to one of claims 1 to 3, wherein the base plate of the drawer (20) has a connecting element (22) on one side. [5] The holder according to one of claims 1 to 4, wherein drawer (20) with optical element, pressure ring (5) and seal (40) are arranged in a housing (60). [6] The holder according to claim 5, wherein the housing (60) has an opening above and below the optical element. [7] The holder according to claim 5 or 6, wherein the housing (60) has a lateral opening through which drawer (20) with optical element, pressure ring (5) and seal (40) can be inserted into the housing (60). [8] The holder according to one of claims 5 to 7, wherein the drawer (20) is connected to a side cover (80) of the housing (60) via the connecting element (22). [9] The holder according to one of claims 5 to 8, wherein a side cover (80) of the housing (60) and an end of the at least one recess in the base plate of the drawer (20) fix a lever (51) of the pressure ring (5) in a position. [10] The holder according to any one of claims 1 to 9, wherein a side cover (80) of the housing (60) is fixed via a locking mechanism (81). [11] The holder according to any one of claims 1 to 10, wherein the optical element comprises lenses, protective glass, mirrors and beam shaping elements. [12] A method for sealing an optical element, comprising the steps - Arrangement of an optical element in a holder according to claim 1; - Inserting the drawer (20) through a side opening into a housing (60) which has an opening above and below the optical element in the inserted drawer (20); - Rotating the pressure ring (5) via a radially outward extending lever (51) of the pressure ring (5) and thus raising the pressure ring (5) by sliding the at least one projection (52) on the underside of the pressure ring (5) in the at least one recess on the top side of the base plate over the ramp (23) in the at least one recess with a seamlessly changing height; - Clamping the pressure ring (5) against the inner top (61) of the housing (60); - Sealing the lower opening (63) of the housing (60) by squeezing the seal (40) between a lower edge of the optical element and an inner lower top surface (61) of the housing (60). [13] The method according to claim 12, wherein the housing (60) is arranged in a further step in a laser material processing head. [14] A laser processing head (100) for laser material processing comprising at least one holder according to any one of claims 1 to 10.

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