Method, clamping tool and device for laser transmission joining

Abstract

The invention relates to a method, a clamping tool and a device for the laser transmission joining of two components, in particular for producing a microfluidic component. A laser-transmissive component (3) and a laser-absorbing component (2) are provided, the laser-transmissive component (3) having a flexible shape. A laser-transmissive clamping tool (6) having a rigid main body (11) and, arranged thereon, an elastically deformable pressure part (12) are provided. The components (2, 3) are arranged in a joining position. A joining pressure (P) is applied to the components (2, 3) by means of the clamping tool (6), wherein the pressure part (12) of the clamping tool (6) rests against the laser-transmissive component (3). Laser radiation (10) is radiated through the laser-transmissive clamping tool (6) and the laser-transmissive component (3) onto the laser-absorbing component (2) in order to weld the components (2, 3) in a welding region.

Description

[0001] Process, clamping tool and device for laser transmission joining

[0002] This patent application claims priority from German patent application DE 10 2023 208 313.2, the contents of which are incorporated herein by reference.

[0003] The invention relates to a method for laser transmission joining two components, in particular for the production of a microfluidic component, for example a microfluidic chip for medical diagnostics and / or fluid-conducting systems, for example in vehicles, and / or for the production of films and / or small components in the electronics industry, particularly in the consumer sector. The invention also relates to a clamping tool for exerting joining pressure during laser transmission joining of two components, as well as a device for laser transmission joining using such a clamping tool.

[0004] Laser transmission joining, also known as laser transmission welding, has proven successful in many applications for the material-to-material joining of components. A laser-transmissive and a laser-absorbing component are prepared and arranged in a joining position. Using a clamping tool, joining pressure is exerted on the components, and laser radiation is directed through the laser-transmissive component onto the laser-absorbing component to join the components in a welding area. Difficulties arise, for example, when one of the components, particularly the laser-transmissive component, is dimensionally flexible. The dimensionally flexible component lacks the necessary rigidity to absorb the joining pressure and distribute it evenly across the welding area. In addition, deformation of the components, particularly the dimensionally flexible component, can occur during the joining process, which can lead to inaccuracies in production.Since flexible components, such as foils, are very thin, there is little or no settling travel, and tolerances in the respective components, resulting from deformations or inaccuracies in upstream processes, cannot be compensated. A maximum settling travel, for example, can be less than 200 μm.

[0005] The object of the present invention is therefore to ensure reliable laser transmission joining of a flexible component with another component, in particular to ensure that precise joining of the components is ensured regardless of unevenness and / or tolerances of the component surfaces.

[0006] This object is achieved by a method having the steps specified in claim 1. The object is further achieved by a laser-transmissive clamping tool according to claim 9 and a device for laser transmission joining according to claim 21. Advantageous embodiments are the subject of the subclaims.

[0007] The method according to the invention for laser transmission joining two components comprises the following steps:

[0008] Providing a laser-transmissive component and a laser-absorbing component, wherein the laser-transmissive component is dimensionally flexible, providing a clamping tool that is laser-transmissive at least in some areas, wherein the clamping tool has a rigid base body and an elastically deformable pressure component arranged thereon, arranging the components in a joining position, applying a joining pressure to the components by means of the clamping tool, wherein the clamping tool rests against the laser-transmissive component with the pressure component, and

[0009] Irradiation of laser radiation through the laser-transmissive clamping tool and the laser-transmissive component onto the laser-absorbing component to weld the components in a welding area.

[0010] The laser-transmissive clamping tool and the irradiation of the laser radiation through the laser-transmissive clamping tool make it possible to apply the joining pressure directly in the welding area. The joining pressure can be precisely adjusted in the welding area; a transmission of the joining pressure through the flexible component is not necessary. The laser-transmissive clamping tool can be penetrated by laser radiation, at least in relevant areas. The clamping tool is laser-transmissive at least in some areas, for example, above the welding area. Preferably, the entire clamping tool is laser-transmissive. Particularly preferably, the base body and pressure component are laser-transmissive. The clamping tool is, in particular, laser-transmissive for wavelengths between 10 nm and 10 6 nm, in particular for wavelengths in the visible (VIS) and / or infrared (IR) wavelength range, for example wavelengths between 400 nm and 2000 nm.

[0011] The rigid base body absorbs the joining pressure, for example, from a clamping frame, and applies the joining pressure to the components. The elasticity of the pressure component applied to the flexible, laser-transmissive component ensures that the joining pressure is applied evenly despite the flexible shape of the laser-transmissive component. In particular, this allows tolerances and unevenness of the component surfaces, especially of the laser-absorbing component, to be compensated. The laser-transmissive component can also be adapted to a surface topology of the laser-absorbing component, for example, to steps, projections, recessed areas, and the like. The elastically deformable pressure component ensures a secure and precise application of the joining pressure on and over the flexible component.

[0012] The elastically deformable pressure component has the particular advantage that damage to a sensitive, flexible component, such as a film, is avoided when the joining pressure is applied.

[0013] The elasticity of the clamping component makes it particularly advantageous to compensate for different unevenness and / or tolerances of components in different welding processes without permanently affecting the clamping tool, especially the clamping component. The clamping component, and especially the entire clamping tool, have a long service life. This reduces setup costs.

[0014] The method can be used in particular for the production of microfluidic components. For example, the laser-absorbing component can have a plurality of fluid channels, in particular a network of fluid channels, in particular microfluidic channels, on the side facing the laser-transmissive component, which are open towards the surface and are covered by the laser-transmissive component in the joining position. Such components can be used in particular in medical technology, for example as microfluidic chips in medical diagnostics. The elastic pressure component ensures that the fluid channels are reliably closed towards the surface without the fluid channels being blocked or closed by the laser-transmissive component. Such components can also be used in other fluid-conducting systems, particularly in the automotive sector.

[0015] Further exemplary fields of application of the process are the production of films and / or small components for the electronics industry, particularly in the consumer sector.

[0016] The laser-transmissive component is dimensionally flexible. Within the meaning of the present invention, dimensionally flexible means, in particular, that the laser-transmissive component is deformable by applying force, in particular by applying force during the joining process, for example, when applying the required joining pressure. The laser-transmissive component can, in particular, be a film.

[0017] The base body of the clamping tool is rigid. A rigid base body within the meaning of the present invention is understood in particular to be a base body that essentially does not deform when force is applied during the joining process, particularly when the required joining pressure is applied. The rigid base body is particularly designed to absorb the joining force, for example, from a clamping frame, and transmit it without essentially deforming.

[0018] The laser-absorbing component is, in particular, rigid. It essentially does not deform, for example, due to the joining pressure. For example, a basic shape of the laser-absorbing component essentially does not change when the joining pressure is applied. It is possible for a clamping device, in particular the clamping tool and / or one or more counter-clamping elements, to cause a slight change in the shape of the laser-absorbing component. Existing deformations of the laser-absorbing component can be reduced, in particular corrected, by means of the joining pressure. For example, the laser-absorbing component may be deformed due to manufacturing tolerances and pressed at least partially to a nominal dimension by the joining pressure. The clamping device, in particular the clamping tool and / or one or more counter-clamping elements, can, for example, have a higher rigidity than the laser-absorbing component.The clamping device, in particular the clamping tool and / or one or more counter-clamping elements, can be manufactured, for example, according to CAD in order to specify a nominal dimension of the components to be joined.

[0019] The pressure component is elastically deformable. In the context of the invention, "elastically deformable" means, in particular, that the pressure component is deformable within the elastic range when subjected to a force, which is required, for example, to apply the joining pressure. The pressure component preferably has a Shore A hardness between 30 and 70, preferably between 40 and 60.

[0020] The pressure component, in particular its elasticity, is preferably designed such that reliable contact between the laser-transmissive component and the laser-absorbing component is ensured in the welding area. For example, the pressure component is designed such that good contact conditions are maintained between the dimensionally flexible laser-transmissive component and the laser-absorbing component despite deformations of the laser-absorbing component and / or local imperfections of the laser-absorbing component, for example due to sink marks during injection molding. Particularly preferably, the elasticity of the pressure component can be selected depending on the tolerances of the components to be joined, in particular of the laser-absorbing component. For example, the Shore hardness of the pressure component, a thickness of the pressure component, and / or the joining pressure can be adapted, in particular optimized, with regard to the contact conditions to be achieved.

[0021] The pressure component is preferably designed to be flat. The pressure component is arranged, for example, on a surface of the base body facing the components. The pressure component forms, in particular, a pressure surface for flat contact with the laser-transmissive component or with one or more partial areas of the laser-transmissive component. The pressure component can, in particular, completely cover the surface of the base body facing the components. The pressure component can also be arranged only in one or more partial areas of the surface of the base body facing the components. The pressure component can, in particular, be designed in several parts, in particular cover several partial areas of the surface of the base body facing the components. For example, the laser-transmissive component can be applied only in one or more partial areas of the surface of the laser-absorbing component.

[0022] The clamping tool, in particular the pressure component, can be designed, for example, to apply the joining pressure in locally limited surface areas of the components to be joined. For example, the pressure component can be arranged on one or more projections of the base body in order to apply the joining pressure to one or more corresponding, for example recessed, areas of the components to be joined. It is also possible for the base body to have depressions between areas of its surface on which the pressure component is arranged. For example, no joining pressure is applied in the area of ​​the depressions. The depressions can serve, for example, to accommodate component areas or components to which no joining pressure should or may be applied.

[0023] The laser-transmissive component lies flat against the laser-absorbing component. Especially in combination with the flat pressure component, lower joining pressures can be achieved than when joining using a weld bar. The applied joining pressure can, for example, be less than 3 N / mm 2 be, in particular between 0.05 N / mm 2 and 3 N / mm 2 , especially between 0.5 N / mm 2 and 2 N / mm 2 The joining pressure can be selected depending on the quality of the components to be joined, especially the laser-absorbing component.

[0024] Common process strategies can be used to apply the laser beam, such as the quasi-simultaneous welding process. Contour welding has proven particularly suitable for applications with little or no settling travel. This results in short process times and increases the cost-effectiveness of the process. Complex welding contours, such as those for fluid channel networks, can be achieved.

[0025] The joining pressure is applied to the components using the clamping tool. Preferably, the components are clamped in a fixed position using the clamping tool, in particular between the clamping tool and a counter-clamping element. The counter-clamping element can be, for example, a component holder. For example, the laser-absorbing component can be positioned on the counter-clamping element, the laser-transmissive component can be arranged on the laser-absorbing component, and pressed down using the clamping tool. To apply the joining pressure, the clamping tool can be clamped, for example, in a clamping frame, in particular in a fixed position.

[0026] According to a preferred aspect of the method, the laser-transmissive component has a thickness between 1 pm and 500 pm, in particular between 50 pm and 250 pm. The laser-transmissive component is, in particular, a film. The reliable connection of thin components, in particular films, to other components is relevant for many applications, particularly in microfluidics. Such thin laser-transmissive components, in particular films, are particularly flexible in shape and benefit particularly from the use of the elastically deformable pressure component.

[0027] A further advantage is that the pressure component can serve as heat protection for the base body of the clamping device. Due to the low thickness of the laser-transmissive component, especially the film, heat transfer from the welding area to the clamping tool is increased. The pressure component can reduce heat transfer to the rigid base body. This increases the range of possible materials for the base body. Transparent plastics, such as acrylic glass, can be used, increasing the design freedom of the base body, particularly for adapting to the geometry of the components.

[0028] According to a preferred aspect of the method, fluid channels open toward the surface are introduced into the surface of the laser-absorbing component, which are covered by the laser-transmissive component in the joining position, with welding taking place along the edges of the fluid channels. The fluid channels in the surface of the laser-absorbing component can, in particular, form a network of fluid channels. The fluid channels can be easily introduced during the production of the laser-absorbing component, for example, by injection molding. The laser-transmissive component, in particular a film, can reliably close the fluid channels toward the surface and seal them off from each other and the environment.Applying the joining pressure via the elastically deformable pressure component ensures that the film is precisely positioned and pressed over the fluid channels without the film protruding into them and at least partially blocking them. The positioning of the film is independent of unevenness and tolerances of the laser-absorbing component, especially its surface.

[0029] According to a preferred aspect of the method, the joining pressure is applied to the laser-transmissive component exclusively via the pressure component. This ensures a particularly uniform application of the joining pressure and reliable tolerance compensation.

[0030] According to a preferred aspect of the method, a pressure surface with which the pressure component rests against the laser-transmissive component covers at least the entire welding area. The clamping tool, in particular the pressure component, can be positioned once and clamped in place. Subsequent deformation of the flexible laser-transmissive component is avoided. The joining pressure can be applied particularly evenly. According to a preferred aspect of the method, the joining pressure is applied essentially perpendicular to a pressure surface with which the pressure component rests against the laser-transmissive component. This ensures particularly precise positioning of the laser-transmissive component and the clamping tool thereon. Unwanted changes in position or deformation of the laser-transmissive component during joining due to joining pressure are avoided.

[0031] According to a preferred aspect of the method, the pressure component is arranged only in selective surface regions of the base body surface facing the components. Arranging the pressure component in selective surface regions enables a particularly targeted and precise application of the joining pressure in the relevant joining regions of the laser-transmissive component, in particular along the welding contours. For example, the pressure component can be arranged in surface regions in which the laser-absorbing component has no recesses, for example no fluid channels. Pressing the laser-transmissive component into these recesses is reliably prevented while, at the same time, the joining pressure is applied reliably and evenly. For example, the pressure component can be formed along edges of the recesses, in particular the fluid channels.

[0032] In particular, it is possible for gaps to be formed between sections of the pressure component in other surface areas of the base body facing the components, where the pressure component is not located. In these areas, there is no direct contact between the clamping tool and the laser-transmissive component. The gaps particularly improve the thermal insulation of the clamping tool from the welding areas.

[0033] According to a preferred aspect of the method, the pressure component is firmly bonded to the base body. The pressure component is stationary, allowing particularly precise definition of the areas where the joining pressure is applied. Production errors are reliably avoided. A firmly bonded connection is particularly advantageous when the pressure component is arranged only in selective surface areas of the base body.

[0034] The material connection can be achieved, for example, by gluing and / or printing the pressure component, for example a pressure component made of silicone, onto the surface of the base body facing the components. For example, additive manufacturing processes, such as 3D printing, can be used to attach the pressure component to the base body, in particular to selective surface areas thereof. It is also possible, in particular, to create three-dimensional structures of the pressure component, for example, areas in which the pressure component has a greater thickness than in other areas. For example, this can be used to adapt the pressure component to the surface topography of the components. It is also possible to locally control the joining pressure.

[0035] The clamping tool provided can preferably have one or more of the features described below with reference to the clamping tool according to the invention. The laser-transmissive clamping tool for exerting a joining pressure during laser transmission joining of two components has a rigid base body for absorbing the joining pressure and an elastically deformable pressure component arranged on the rigid base body for bearing against the laser-transmissive component to apply the joining pressure to the components. The rigid base body can absorb the joining pressure, for example, from a clamping frame. For example, the clamping tool can be fixedly clamped in a clamping frame. The clamping tool is particularly suitable for reliably and precisely applying the joining pressure to a dimensionally flexible laser-transmissive component. The elastically deformable pressure component prevents damage to a dimensionally flexible component, for example a film.In addition, a uniform application of joining pressure to a flexible component is ensured, especially while simultaneously compensating for tolerances. The clamping tool can be used, for example, in the production of microfluidic chips, for example, for medical diagnostics.

[0036] According to a preferred aspect of the clamping tool, it has a laser radiation transmission of at least 50%, at least in the areas to be irradiated. The laser radiation for which the transmission is given can, in particular, have a wavelength in a wavelength range between 10 nm and 10 6nm, for example in the visible and / or infrared wavelength range. The laser radiation is only slightly attenuated by the clamping tool. The laser radiation can be efficiently radiated through the clamping tool onto the components to be joined. Energy input into the clamping tool is reduced. The transmission of the laser radiation can in particular be at least 85%. According to a preferred aspect of the clamping tool, it has a force absorption capacity of between 0.05 N / mm 2 and 10 N / mm 2 The clamping tool can be used for a wide range of required joining pressures. The force absorption capacity is between 0.5 N / mm 2 and 3 N / mm 2 , for example between 0.5 N / mm 2 and 2 N / mm 2 .

[0037] According to a preferred aspect of the clamping tool, in particular the pressure component, it has a heat distortion temperature (HDT) of at least 125 °C, in particular of at least 150 °C. The heat distortion temperature can be determined in particular according to DIN EN ISO 75-1 to 75-3 and / or ASTM D 648. The clamping tool is particularly suitable for welding thin laser-transmissive components, for example, films, which lead to a high heat transfer from the welding area to the clamping tool. The heat distortion temperature can be ensured in particular by the material and / or design of the pressure component.

[0038] The clamping tool, in particular the pressure component, can preferably have a continuous operating temperature of at least 125 °C, in particular of at least 150 °C. The continuous operating temperature is the maximum temperature at which the materials can be used for 20,000 hours without losing more than half of their original strength and elongation properties.

[0039] According to a preferred aspect of the clamping tool, the pressure component has a thickness between 0.1 mm and 5 mm. The thickness of the pressure component is, in particular, perpendicular to a pressure surface with which the pressure component rests against the laser-transmissive component. The thickness of the pressure component is particularly suitable for ensuring sufficient elastic deformability while simultaneously reliably applying the joining pressure. The thickness of the pressure component can be selected depending, in particular, on the material of the pressure component and / or the required deformability of the pressure component.

[0040] Particularly preferably, the base body has a thickness between 2 mm and 50 mm. The thickness of the base body can be selected, in particular, depending on the material of the base body in order to ensure sufficient rigidity of the base body to absorb and transmit the joining pressure.

[0041] According to a preferred aspect of the clamping tool, it is adapted to the geometry of the components. The clamping tool can, in particular, have a shape that is adapted to the laser-absorbing component, in particular to the surface topology. The clamping tool can, for example, be plate-shaped. The clamping tool can, in particular, also have a complex three-dimensional shape, in particular, not be plate-shaped. For example, the clamping tool can be adapted to a height profile of the surface, for example, to steps in the area of ​​the surface, in particular of the laser-absorbing component. For example, joining the flexible laser-transmissive component in a recessed area of ​​the surface of the laser-absorbing component may be desired or required. The pressure component can, for example, be arranged on a protruding area of ​​the base body that projects into a recessed area of ​​the laser-absorbing component.

[0042] The shape of the clamping tool, particularly the pressure component, allows a flexible component, such as a film, to be adapted to the surface topology of the laser-absorbing component. By applying the joining pressure, the laser-transmissive component, such as the film, can be formed into the desired shape to be joined.

[0043] The pressure component can be made of an elastic plastic, for example, polyvinyl chloride (PVC). According to a preferred aspect of the clamping tool, the pressure component consists of an elastomer, in particular a silicone. The pressure component has advantageous, particularly adaptable, elasticity. The elastomer, in particular the silicone, exhibits high long-term temperature resistance. The elastomer, in particular the silicone, can serve as heat protection for the base body. The pressure component is also chemically insensitive, for example, to common cleaning agents. The service life of the clamping tool is further increased. Depending on the application, suitable silicones can be selected from a wide range of grades.

[0044] According to a preferred aspect of the clamping device, the base body is made of glass or a transparent plastic. Suitable transparent plastics are, in particular, polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin copolymers (COC), and / or cycloolefin polymers (COP). PMMA has proven to be a particularly suitable transparent plastic. Glass and transparent plastics, especially PMMA, have high transmission for laser radiation in relevant wavelength ranges. Furthermore, glass and transparent plastics, especially PMMA, exhibit high rigidity, allowing high joining pressure to be absorbed and applied to the components.

[0045] The use of glass has the particular advantage of being a chemically inert and stable material. Glass is particularly advantageous for the transmission of laser radiation.

[0046] Transparent plastic, especially PMMA, is inexpensive to manufacture. Plastic, especially PMMA, can be easily manufactured in complex geometries, thus increasing design freedom for the base body. The lower temperature resistance of plastic can be compensated for, for example, by the pressure component. Transparent plastic, especially PMMA, can be combined with silicone to particular advantage.

[0047] According to a preferred aspect of the clamping tool, the base body and the pressure component are integrally connected. For example, the base body and pressure component can be glued to one another. The pressure component can, for example, be attached, in particular glued, as a flat pressure component to a surface of the base body facing the components. Before connecting the pressure component to the base body, the corresponding surface of the base body can be prepared, in particular cleaned and / or activated. According to a preferred aspect of the clamping tool, the pressure component is glued or printed onto the surface of the base body facing the components. For example, the pressure component can be applied to the surface of the base body, in particular in selective surface regions thereof, using additive manufacturing methods, in particular 3D printing.

[0048] According to a preferred aspect of the clamping tool, the pressure component is arranged only in selective surface areas of the base body surface facing the components. This enables precise and controllable determination of the joining pressure. Furthermore, heat transfer to the clamping tool, in particular the base body, is reduced.

[0049] According to a preferred aspect of the clamping tool, the pressure component has a Shore A hardness between 30 and 70, preferably between 40 and 60. This ensures sufficient elasticity while simultaneously reliably applying the joining pressure. The Shore hardness can be selected depending, in particular, on the thickness of the pressure component and / or the contact conditions to be achieved between the laser-transmissive component and the laser-absorbing component.

[0050] The base body preferably has a high surface quality, in particular a low surface roughness, on its side facing away from the pressure component. This minimizes, in particular prevents, scattering effects for the laser radiation. The laser radiation can be irradiated with particular precision, for example, to create complex welding contours along a network of fluid channels. The device for laser transmission joining two components, in particular for manufacturing a microfluidic component, has a clamping device for applying a joining pressure to the components with the clamping tool described above and a laser device for irradiating laser radiation onto a welding area through the clamping tool.

[0051] The laser device can, for example, comprise a laser plotter and / or laser scanner, such as a galvanometer scanner, for the targeted application of laser radiation. For example, the welding area, in particular a welding contour, can be traversed with the laser radiation, particularly in the contour welding process.

[0052] In addition to the clamping tool, the clamping device can have a clamping frame for applying the joining pressure to the clamping tool. The clamping tool can be clamped into the clamping frame, in particular, fixedly clamped. The clamping device can also have counter-clamping elements, for example in the form of a component holder into which the laser-absorbing component can be inserted.

[0053] Further features, details, and advantages of the invention will become apparent from the following description of an embodiment with reference to the accompanying drawings. They show:

[0054] Fig. 1 is a schematic representation of a device for laser transmission joining and the joining process carried out therewith, and Fig. 2 is a schematic representation of a further embodiment of a device for laser transmission joining and the joining process carried out therewith.

[0055] Fig. 1 shows a device 1 for laser transmission joining a laser-absorbing component 2 to a laser-transmissive component 3. The laser-transmissive component 3 is flexible in shape; in the exemplary embodiment shown, it is a film with a thickness of between 1 pm and 500 pm. The components 2, 3 are shown in their joining position in Fig. 1. On the surface of the laser-absorbing component 2 facing the laser-transmissive component 3, a network of fluid channels 4, in the form of microfluidic channels, is formed. The fluid channels 4 are open towards the surface and, after the components 2, 3 have been joined, are closed at the top by the laser-transmissive component 3 and sealed against one another and the environment. The joined components 2, 3 are, for example, part of a microfluidic component, for example a microfluidic chip for medical diagnostics.

[0056] The device 1 has a clamping device 5 with a laser-transmissive clamping tool 6. With the help of the clamping device 5, a joining pressure P is applied to the components 2, 3 in the joining position. For this purpose, the clamping device 5 has a clamping frame 7 and a counter-clamping element 8 in the form of a component holder. The laser-absorbing component 2 is placed in the component holder 8 and the laser-transmissive component 3 is positioned thereon. The clamping tool 6 is pressed against the laser-transmissive component 3 with the help of the clamping frame 7 and clamped in place. The clamping tool 6 absorbs the joining pressure P generated with the help of the clamping frame 7 and applies it to the components 2, 3. With the help of a laser device 9, laser radiation 10 is irradiated in a targeted manner onto the areas of the components 2, 3 that are to be welded.The laser device 9 has a laser scanner, for example, a galvanometer scanner. In this case, the welding area is a welding contour that runs along the edges of the fluid channels 4. The laser radiation 10 is radiated through the laser-transmissive clamping tool 6 and the laser-solid component 3 onto the laser-absorbing component 2. The laser-transmissive clamping tool 6 therefore enables the joining pressure P to be applied directly in the welding area, particularly along the welding contour.

[0057] The tool 6 has a rigid base body 11 and an elastically deformable pressure component 12. The rigid base body 11 serves to absorb the joining pressure P from the clamping frame 7. The pressure component 12 bears against the laser-transmissive, form-flexible component 3 with a pressure surface 13. The joining pressure P is applied to the component 3 exclusively via the pressure component 12. The pressure surface 13 covers at least the entire welding area. The elastic deformability of the pressure component 12 has the advantage that the form-flexible component 3 is not damaged. Furthermore, the form-flexible component 3 is securely held on the laser-absorbing component 2, whereby unevenness in the surface of the laser-absorbing component 2 can be compensated. This enables precise and reliable welding of the components 2, 3, particularly along the fluid channels 4.The fluid channels 4 are reliably sealed by the laser-transmissive component 3 without being clogged or blocked by the laser-transmissive component 3. The surface 14 of the base body 11 facing away from the components 2, 3 has a high surface quality, in particular a low surface roughness. This minimizes scattering effects for the laser radiation 10, ensuring precise irradiation onto the welding area, particularly along the fluid channels 4.

[0058] The pressure component 12 has a thickness d between 0.1 mm and 5 mm in the direction perpendicular to the pressure surface 13. This ensures reliable transmission of the joining pressure P while simultaneously providing sufficient elastic deformability for tolerance compensation. The base body 11 has a thickness D between 2 mm and 50 mm perpendicular to the pressure surface 13.

[0059] The pressure component 12 and the base body 11 are firmly bonded together. The pressure component 12 is glued to a previously cleaned and activated surface of the base body 11.

[0060] The base body 11 is preferably made of glass. The base body 11 has a high optical quality, is chemically inert, and stable. The base body 11 can also be made of a transparent plastic, in particular PMMA. PMMA has the advantage that it can be manufactured cost-effectively in any desired geometry. The clamping tool 6 can therefore be easily adapted to a geometry of the components 2, 3, in particular to a surface topology of the laser-absorbing component 2. In particular, it is possible to reproduce complex surface topologies of the component (not shown), for example by providing corresponding projections for recessed areas. By adapting to the shape, it can also be ensured, in particular, that the dimensionally flexible component 3 is brought into and held in a corresponding desired shape for joining to the component 2.

[0061] The pressure component 12 is made of silicone. Silicone has a suitable elasticity. Silicone has the additional advantage of being chemically insensitive, for example, to cleaning agents.

[0062] The pressure component 12, particularly made of silicone, serves primarily as a heat shield for the base body 11. Due to the thin thickness of the laser-transmissive component 3, heat transfer from the welding area to the clamping tool 6 is increased. Silicone has a high heat deflection temperature. This makes it possible to use base body materials that are themselves less temperature-resistant. The combination of PMMA for the base body 11 and silicone for the pressure component 12 is particularly advantageous in this regard.

[0063] Fig. 2 shows a further embodiment of a device 1a for laser transmission joining with a laser-transmissive clamping tool 6a. Components that have already been described with reference to the embodiment in Fig. 1 bear the same reference numerals and will not be explained in detail again. Components that are functionally identical but structurally different bear the same reference numerals with a suffix "a."

[0064] The device 1a differs from the device 1 according to Fig. 1 only in the design of the clamping tool 6a, in particular in its pressure component 12a. The pressure component 12a is arranged on the base body 11 only in selective surface areas of the surface facing the components 2, 3. The pressure component 12a is thus not arranged over the entire surface of the base body 11.

[0065] Between sections 20 of the pressure component 12a, free spaces 21 are formed in which the clamping tool 6a is not in direct contact with the laser-transmissive component 3. In the illustrated embodiment, the sections 20 of the pressure component 12a run in partial surface areas along the edges of the fluid channels 4 formed in the laser-absorbing component 2. This ensures a particularly targeted and precise application of the joining pressure P in the areas relevant to the welding process. Heat transfer to the clamping tool 6a is reduced by the selective attachment of the pressure component 12a. The sections 20 of the pressure component 12a can, in particular, represent a negative image of the fluid channels 4.

[0066] In the illustrated embodiment, the pressure component 12a is integrally bonded to the base body 12. For example, the sections 20 can be glued to the base body 11. It is also possible to print the pressure component 12a onto the base body 11, particularly using 3D printing. This enables a targeted application of the pressure component 12a and—in embodiments not shown in the figures—a three-dimensional structure of the pressure component.

[0067] The pressure component 12a can in particular be made of silicone, which has proven to be particularly suitable for the selective attachment of the pressure component 12a.

Claims

Patent claims 1. Method for laser transmission joining two components (2, 3), in particular for manufacturing a microfluidic component, comprising the steps: Providing a laser-transmissive component (3) and a laser-absorbing component (2), wherein the laser-transmissive component (3) is dimensionally flexible, Providing a laser-transmissive spacing tool (6; 6a), wherein the spacing tool (6; 6a) has a rigid base body (11) and an elastically deformable pressure component (12; 12a) arranged thereon, Arranging the components (2, 3) in a joining position, Applying a joining pressure (P) to the components (2, 3) by means of the spaim tool (6; 6a), wherein the spaim tool (6; 6a) bears against the laser-transmissive component (3) with the pressure component (12; 12a), and Irradiation of laser radiation (10) through the laser-transmissive spaim tool (6) and the laser-transmissive component (3) onto the laser-absorbing component (2) for welding the components (2, 3) in a welding area.

2. Method according to claim 1, characterized in that the laser-transmissive component (3) has a thickness between 1 pm and 500 pm, in particular between 1 pm and 50 pm.

3. Method according to one of the preceding claims, characterized in that fluid channels (4) open towards the surface are introduced into a surface of the laser-absorbing component (2), which are formed by the laser-transmissive component (3) is covered in the joining position, whereby welding takes place along the edges of the fluid channels (4).

4. Method according to one of the preceding claims, characterized in that the joining pressure (P) on the laser-transmissive component (3) is introduced exclusively via the pressure component (12; 12a).

5. Method according to one of the preceding claims, characterized in that a pressure surface (13) with which the pressure component (12; 12a) bears against the laser-transmissive component (3) covers at least the entire welding area.

6. Method according to one of the preceding claims, characterized in that the joining pressure (P) is introduced substantially perpendicular to a pressure surface (13) with which the pressure component (12; 12a) bears against the laser-transmissive component (3).

7. Method according to one of the preceding claims, characterized in that the pressure component (12a) is arranged only in selective surface sub-areas of the surface of the base body (11) facing the components (2, 3).

8. Method according to one of the preceding claims, characterized in that the pressure component (12; 12a) is firmly attached to the base body (11).

9. Laser-transmissive clamping tool (6; 6a) for exerting a joining pressure (P) during laser transmission joining of two components (2, 3), in particular for producing a microfluidic component, comprising a rigid base body (11) for absorbing the joining pressure (P), for example from a clamping frame (7), and an elastically deformable pressure component (12; 12a) arranged on the rigid base body (11) for bearing against the laser-transmissive component (3) for applying the joining pressure (P) to the components (2, 3).

10. Clamping tool according to claim 9, characterized by a transmission of the laser radiation (10) in areas to be irradiated of at least 50%.

11. Clamping tool according to one of claims 9 or 10, characterized by a force absorption capacity between 0.05 N / mm2 and 10 N / mm 2 .

12. Clamping tool according to one of claims 9 to 11, characterized by a heat distortion temperature of at least 125 °C.

13. Clamping tool according to one of claims 9 to 12, characterized in that the pressure component (12; 12a) has a thickness (d) between 0.1 mm and 5 mm.

14. Clamping tool according to one of claims 9 to 13, characterized by a clamping device adapted to the geometry of the components (2, 3), in particular to the Surface topography of the laser-absorbing component (2), adapted shape.

15. Clamping tool according to one of claims 9 to 14, characterized in that the pressure component (12; 12a) consists of an elastomer, in particular of a silicone.

16. Clamping tool according to one of claims 9 to 15, characterized in that the base body (11) consists of glass or a transparent plastic, in particular of glass or polymethyl methacrylate.

17. Clamping tool according to one of claims 9 to 16, characterized in that the base body (11) and the pressure component (12; 12a) are integrally connected.

18. Clamping tool according to claim 17, characterized in that the pressure component (12; 12a) is glued or printed onto the surface of the base body (11) facing the components (2, 3).

19. Clamping tool according to one of claims 9 to 18, characterized in that the pressure component (12a) is arranged only in selective surface partial areas of the surface of the base body (11) facing the components (2, 3).

20. Clamping tool according to one of claims 9 to 19, characterized in that the pressure component (12; 12a) has a Shore A hardness between 30 and 70, preferably between 40 and 60.

21. Device for the laser transmission joining of two components (2, 3), in particular for the production of a microfluidic component, comprising a laser-transmissive clamping device (5; 5a) for applying a joining pressure (P) to the components (2, 3), with a clamping tool (6; 6a) according to one of claims 9 to 20, and a laser device (9), in particular with a laser scanner, for irradiating laser radiation (10) onto a welding area through the clamping tool (6; 6a).

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