METHOD AND DEVICE FOR JOINING A COMPOSITE SHEET METAL COMPONENT TO ANOTHER COMPONENT

Description

[0001] The invention relates to a method for joining a first component to a second component at a joining point of the first component, wherein the first component has at least one substantially planar first component, a substantially planar second component and a plastic-containing intermediate layer arranged at least in regions between the two components.

[0002] Lightweight construction concepts, for example based on aluminum materials or composite sheet components, are well known in automotive engineering. The combination of high-strength steels for crash-relevant components with multi-layer composite sheets for large-area components represents a more economically advantageous lightweight construction concept than the use of aluminum materials, particularly in body construction. Composite sheets typically consist of thin steel cover sheets, for example 0.2 mm to 0.3 mm thick, and a plastic-containing intermediate layer, for example made of thermoplastic, with a thickness of typically between 0.2 mm and 1.5 mm. Compared to other known body sheets, the weight per unit area is significantly lower. A further advantage of such composite sheet components is their high flexural strength.

[0003] The intermediate layer arranged between the two thin steel cover sheets is electrically insulating and therefore unsuitable for resistance, arc, and beam welding. Therefore, joining technologies suitable for large-scale production of such composite sheet components in car body construction must be further developed. However, thermal joining processes cannot be used reliably due to the intermediate layer. The high process temperatures lead to significant foam and spatter formation and damage to the composite sheet component. The material-to-material attachment of sheet-like components as well as functional elements, such as fasteners such as bolts and nuts, is also impossible due to the intermediate layer. When mechanically joining functional elements, such as fasteners, the plastic intermediate layer leads to a reduction in the joint strength.The clamping force generated in the joining process between the composite sheet component and a functional element can be reduced in the KTL process at temperatures in the range of approximately 180°C due to creep processes in the material of the intermediate layer.

[0004] According to the current state of the art, sheet metal components are therefore preferably joined mechanically to the composite sheet metal component. Joining methods for connecting composite sheet metal components with functional elements, such as fasteners such as bolts and nuts, are not yet known in the state of the art. State of the art

[0005] To weld multilayer composite sheets, it is already known from DE 101 11 567 A1 to produce components partially without an insulating intermediate layer. Resistance spot welding is possible at these locations.

[0006] From DE 10 2011 054 362 A1 a method for producing a composite sheet metal part with a metallic edge region is known, wherein it has two outer cover sheets made of metal and at least one layer consisting of a plastic arranged between the cover sheets.

[0007] WO 2013 / 020 636 A1 (on which the preamble of claim 1 is based) describes a method for joining sheet-like components with an intermediate layer made of thermoplastic material to prepare a joint. It is proposed to melt and displace the intermediate layer in certain areas and to create a material-to-material bond between the two components by welding. For this purpose, after displacing the intermediate layer, a welding current is applied in one area until at least one of the two components heats above its melting point and partially liquefies. This allows a material-to-material bond between the two components to be created.

[0008] US 4,650,951 A describes a method for resistance welding two laminates, each laminate having a structure consisting of two metal layers and an insulating layer arranged between them.

[0009] FR 2 638 668 A1 describes a method for welding two composite plates, each of which has an electrically insulating polymer layer between two metal layers. Description of the invention: task, solution, advantages

[0010] The object of the present invention is to further improve a method for joining a multi-layer component to another component, wherein an intermediate layer of the multi-layer component consists of a plastic-containing intermediate layer, in such a way that the joint preparation on the multi-layer component can be carried out quickly and cost-effectively.

[0011] This problem is solved by the features specified in claim 1.

[0012] A method is provided for joining a first component to a second component at a joint of the first component. The first component comprises at least one flat first component and a flat second component, as well as a plastic-containing intermediate layer arranged at least partially between the two components.

[0013] According to the invention, the first component is thus multi-layered, preferably as a composite sheet metal component. For the purposes of the invention, a flat design means that the longitudinal and / or widthwise extension is greater than the thickness of the component. For example, the two components of the first component are sheet-like, preferably steel-containing, components. The plastic-containing intermediate layer is electrically insulating and preferably elastic or thermoplastic. Particularly preferably, the plastic-containing intermediate layer consists of polyethylene or polyamide, or of a combination of polyethylene and polyamide.

[0014] The method according to the invention for joining or connecting the two components in the region of the joint of the first component provides the steps a) to d) according to claim 1. For the purposes of the invention, joining of components means joining the components.

[0015] Steps a) to d) can be performed sequentially, or at least partially in parallel, or overlapping. For example, steps a) and b) could be performed at least partially overlapping. Preferably, steps a) to d) are performed in the aforementioned order.

[0016] Contact between the two components in the area of ​​the joint means that the two components touch each other in this area, since the intermediate layer is displaced by the heating and pressure exerted on the two components in this area. Applying the electrical voltage in step c) thus creates electrical contact between the two components. Thus, it is preferably provided that at least step c) is only carried out, or an electrical voltage is only applied, to the two components once contact between the two components has been established.

[0017] In step c), the voltage is controlled such that a temperature in the contact area between the first component and the second component does not rise above a predetermined temperature threshold. It is provided that the predetermined temperature threshold is lower than the melting point of a material of the first component and also lower than the melting point of a material of the second component.

[0018] The materials of the two components are therefore not liquefied in the contact area by the heat generated by the current flow. Preferably, therefore, no partial or regional liquefaction of these materials is provided. The material of both components remains in a solid state when current is applied and the resulting heating occurs. Due to the heating resulting from the current supply and the exertion of the compressive force on one or both components, the two components are adhered to one another in the contact area. Welding of the two components, whereby the temperature in the contact area rises above the melting point of the materials of the two components in order to create a material-to-material connection between the components and this area, is therefore not provided for.

[0019] Because the two components are only heated in the contact area by the current supply to such an extent that the material of both components does not liquefy, the fastest and most cost-effective connection and thus joint preparation can be achieved. Due to the relatively low temperature, the cycle time for joint preparation can be significantly increased. Furthermore, wear on the tools used in the process, such as caps or electrode caps of specially manufactured or modified welding guns, is significantly reduced.

[0020] The predetermined temperature threshold is preferably less than 1,600°C, particularly preferably less than 1,530°C, and very particularly preferably less than 1,500°C.

[0021] When heating one or both components in step a), the component(s) are heated to a temperature between 200°C and 600°C on the surface, i.e. in the area in which the tempered tool heats the first component and / or the second component.

[0022] Preferably, the electrical voltage in step c) is applied until the intermediate layer is thermally destroyed due to heating caused by an electric current flow in a first region adjacent to the joint.

[0023] The material of the intermediate layer displaced in the region of the joint between the two components is thus thermally destroyed in a first region, i.e., in a zone arranged around the joint and between the two components, such that the material of the intermediate layer is no longer flowable in this first region, even after cooling. Thus, the properties are changed by heating the material of the intermediate layer such that the material of the intermediate layer no longer exhibits flowable properties in this region. In step c), the electrical voltage is preferably applied or adjusted such that the displaced material in the first region exhibits cavities, at least in some regions.

[0024] The electrical voltage can, for example, be applied to the two components after a predetermined period of time has elapsed. The time period is defined such that it can be assumed with sufficient certainty that contact has been established between the two components in the region of the joint as a result of the heating in step a) and the application of pressure in step b). Preferably, step b) detects when contact has been established between the first component and the second component in the region of the joint in order to apply the electrical voltage in step c). Thus, the time at which the electrical voltage is applied is not dependent, or at least not exclusively, on a predetermined period of time. Particularly preferably, a signal generated by the detection of the contact is used to apply the electrical voltage in step c) or to initiate step c).

[0025] The detection of contact between the two components is preferably carried out using a test voltage. For this purpose, a test voltage is applied to the two components. Resistance and / or current measurements are used to detect when contact is established between the two components in the area of ​​the joint. The test voltage can be applied via the tools used in step a) and / or step b), for example, punches.

[0026] Furthermore, the contact between the two components can be detected by means of displacement measurement. For example, the stroke or displacement of at least one tool for applying pressure in step b) can be measured. Contact can be established when the stroke or displacement traveled by a tool corresponds to the thickness of the intermediate layer in this area. When using two tools for applying pressure in step b), with both tools being moved in opposite directions, contact can be established when the stroke or displacement traveled by both tools in total corresponds to the thickness of the intermediate layer.

[0027] By adaptively controlling the current supply, the process time for process step c) can be further minimized. Preferably, the current flow is initiated immediately after contact is detected between the two components.

[0028] Due to the heating in step a), the intermediate layer between the two components is plasticized and melted in a first process step. The heating of the intermediate layer can be transferred, for example, through the components into the intermediate layer by a heat flow from suitable tools, such as press dies, pressing tools, or welding electrodes. The application of the force in step b) displaces the intermediate layer in this area. The duration of heating of the intermediate layer can be influenced by the temperature and the pressing force.

[0029] After performing steps a) to c), electrical conductivity perpendicular to the layer structure of the first component is permanently ensured, since the material of the intermediate layer in the area of ​​the joint is permanently displaced. According to the invention, process steps a) to c) are therefore referred to as process steps for joint preparation. Step d) comprises the subsequent joining process between the first multilayer component and another, namely the second, component.

[0030] The joint, or the area in which the intermediate layer is displaced between the two components, can have any geometry depending on the temperature-controlled tools, for example press dies. Furthermore, the geometry depends essentially on the design of the second component, which is to be joined to the first multi-layer component in step d). For example, the joint in steps a) to c) can be circular or track-shaped. For a downstream resistance spot welding process or an arc stud welding process, the diameter of the joint is preferably between 2 mm and 20 mm. For downstream resistance projection welding of functional elements, for example fasteners such as nuts or bolts, the diameter of the joint can preferably be up to 30 mm.

[0031] Preferably, steps a) to c) are carried out continuously along a predetermined line or path of the first component in order to form the joint in a path-like manner. The path-like joint can have a width of between 1 mm and 20 mm. The length of the path-like joint can be between 3 mm and the maximum length of the first component. The path-like joint can also be arranged along several side edges of the first component, for example circumferentially closed and thus along four side edges. Thus, the path-like joint can be arranged along part of the first component or along the entire length or width of the first component. The path-like joint is preferably arranged in the edge region of the first component.In order to arrange a web-shaped joint in steps a) to c) continuously along a predetermined line of the first component, preferably one roller-shaped tool, and particularly preferably two roller-shaped tools, are provided. Thus, for example, the web-shaped joint can be arranged by resistance roller seam welding. The roller-shaped tool(s) can have one or more heating elements in order to carry out the heat input to one or both components in step a). Furthermore, the roller-shaped tool(s) can be designed to exert a compressive force on one or both components in step b). It is also preferably provided that the roller-shaped tool(s) are designed to apply an electrical voltage. Thus, all steps a) to c) for preparing the joint can be carried out with one or both roller-shaped tools.The roller-shaped tool(s) are preferably moved at a predetermined speed and / or step by step or in batches along one or both surfaces of the components.

[0032] Furthermore, it is preferably provided that the compressive force in step b) is exerted on the first component in such a way that a depression is created on a surface of the first component in the region of the joint. Furthermore, it is preferably provided that the compressive force is exerted on the second component in such a way that a substantially flat or level surface remains on a surface of the second component in the region of the joint. Thus, it is preferably provided that the tools for exerting the compressive force in step b) are designed in such a way that a depression is created only on one side surface of the first component after the material of the intermediate layer has been displaced in this area. The opposite surface of the first component therefore preferably remains flat or level.

[0033] The tools, for example, punches, for exerting the compressive force in step b) are preferably also used to heat the first and / or second component. For this purpose, the tools are subjected to a temperature. Particularly preferably, the tools for heating the first component and the second component are subjected to different temperatures. For example, a tool with a substantially flat pressure surface can be subjected to a lower temperature, while a tool with a curved, for example, convex, pressure surface can be subjected to a higher temperature.

[0034] Preferably, in step d), the second component is connected in the region of the joint of the first component by welding, for example by resistance spot welding, arc stud welding, or resistance projection welding. The second component can be flat, i.e., sheet-metal-shaped. Furthermore, it is preferably provided that the second component is designed as a functional element, for example as a connecting means for connecting to another component or element. For example, the connecting means can be a nut, projection nut, or bolt. Another component or element can be attached, for example screwed or clamped, to such a functional element or connecting means. In order to screw another component or element onto the connecting means, the connecting means, for example the nut, can have an internal thread or an external thread.Further components or elements that are attached to the connecting means can be, for example, electrical cables, for example ground cables, or also trim parts, for example interior trim, fittings or the like. In vehicle construction, for example, ground cables can thus be avoided or reduced. By connecting a ground connection, for example of a vehicle headlight, to a connecting means that is connected to the first component according to the method according to the invention and thus has an electrical connection to the first component, additional ground cables can be eliminated. The ground connection can thus be established via the first component or the surface of the first component.

[0035] Furthermore, it is preferably provided that, prior to connecting or joining the first component to the second component in step d), a hole is drilled through the first component in the region of the joint. This allows for a subsequent screw connection to be prepared in the region of the joint between the first component and another component. Alternatively, the hole can be punched through the first component in the region of the joint. The punching or drilling process can take place in a separate operation or be integrated into the tool for steps a), b), and / or c).

[0036] A second component, such as a connecting element, can be arranged in the hole through the first component in the area of ​​the joint and mechanically connected to the first component. For example, a connecting element can be inserted through the hole in the first component and clamped, glued, or welded. The connecting element arranged in the hole and connected to the first component preferably has an internal thread for receiving a screw connection.

[0037] The second component, like the first component, can be designed with a large surface area, for example, in the form of a sheet. Furthermore, the second component can also be designed in multiple layers, in particular as a composite sheet. The first and / or second component can also be designed as a multi-layered sheet. For example, a multi-layered sheet consisting of two or more composite sheets can be provided for this purpose.

[0038] An adhesive layer is preferably arranged at least in some areas between the first component and the second component.

[0039] The second component is preferably designed as a functional element, for example as a connecting means such as a nut, projection nut or bolt. The functional element or the connecting element can be placed on the first component in the region of the joint and connected to the first component. Alternatively, the second component can be inserted through a hole arranged in the first component in the region of the joint and connected to the first component. The connecting means, for example the nut, projection nut or bolt, can be connected to the first component by means of a mechanical or thermal process. For example, the connecting means can be connected to the first component by means of arc stud welding, resistance projection welding or similar welding processes.Furthermore, the connecting element could be connected to the first component by a clamping connection, in particular when the connecting means is arranged in a hole, in the region of the joint with the first component.

[0040] It is also preferably provided that a maximum width of the connecting element is smaller than the maximum width or the diameter of the joint. Particularly preferably, the maximum width of the connecting element is smaller than half the maximum width or half the diameter of the joint. The maximum width of the connecting element can, for example, be an outer diameter of the connecting element.

[0041] Furthermore, a device for preparing a joint on a first component for joining the first component to a second component at the joint of the first component is provided. The device is designed for joint preparation for carrying out a method according to claims 1 to 8.

[0042] The device for joint preparation preferably has a first pressure means for exerting a compressive force on the first component of the first part, and a second pressure means for exerting a compressive force on the second component of the first part. It is preferably provided that one of the two pressure means has a substantially flat pressure surface. The other pressure means can have any suitable pressure surface. For example, the other pressure means can have a convex pressure surface. The convex pressure surface of a pressure means creates a depression in a surface of the first component when a compressive force is exerted in step b).Because the other pressure means has a substantially flat pressure surface, the opposite outer surface of the first component continues to be flat or level after the pressure force has been exerted in step b).

[0043] The pressure surface of one or both pressure means can furthermore preferably be strip-shaped. The pressure means can be designed as a stamp, for example as a press stamp, or as the electrode cap of a welding device. Furthermore, the pressure means can be roller-shaped to form a web-shaped joint. One or both pressure means can have heating elements for generating the heat for step a). Furthermore, one or both pressure means can have a detection means for detecting contact between the two components during the application of the compressive force in step b). Particularly preferably, at least one heating element in a pressure means is designed such that it has high thermal conductivity at a first end and poor thermal conductivity at a second end.This allows heat to be introduced into one of the two components in the region of the first end particularly effectively. In the region of the second end, however, no heat is introduced into the device, or only to a very small extent. Short description of the drawings

[0044] They show: Figure 1a shows the method steps a) to c) for preparing a joint on a first multi-layer component, Figure 1b shows the different zones in the area of ​​the joint, Figure 2a shows the method step d) for connecting the first component at the prepared joint to a second sheet-like component, Figure 2b shows the method step d) for connecting a first component in the area of ​​the prepared joint to a second component designed as a bolt, Figure 2c shows the method step d) for connecting the first component in the area of ​​the prepared joint to a second component designed as a nut, Figure 2d shows the method step d) for connecting the first component in the area of ​​the prepared joint to a second annular component arranged in the hole through the first component, Figures 3a - 3c show different designs of pressure means for carrying out the method steps a) to c),and Figure 4 shows a device for joint preparation. Preferred embodiments of the invention

[0045] Figure 1a shows the process steps a) to c) for preparing a joint 15 on a first component 10. The first component 10 is multi-layered and has two sheet-like components 12, 13 and an intermediate layer 14 arranged between the two components 12, 13. The intermediate layer is designed as a plastic-containing layer. In order to join the first component 10 to a second component 11 (in Figure 1a To join two components (not shown), the joining process must be designed such that a joining point 15 is prepared before the first component 10 is joined to a second component 11. It is essential that the intermediate layer 14 is displaced in the region of the joining point 15, so that contact is created between the two components 12, 13 in this area.

[0046] The pressure means 26, 27 for exerting the pressure force in step b) can be, for example, electrode caps of a welding device. Furthermore, different tools can be used for the individual process steps a) to c). As shown in Figure 1a As shown, in this example, the same tools, namely the pressure means 26, 27, are used for process steps a) to c). For this purpose, the two pressure means 26, 27 have heating elements 29 and connections for connecting an electrical voltage 17.

[0047] In a first process step, the two preheated pressure means 26, 27 are placed on the respective surface of a component 12, 13. The pressure means 26, 27 are heated to a temperature between 200°C and 500°C via the heating elements 29.

[0048] In a second step, a compressive force 16 is exerted on the components 12, 13 with the two pressure means 26, 27 until the intermediate layer 14 has been displaced in the region of the joint 15 to be prepared between the first component 12 and the second component 13 and contact is established between the two components 12, 13.

[0049] As soon as contact is established between the two components 12, 13 in this area, an electrical voltage 17 is applied to the two pressure means 26, 27. This conducts an electrical current perpendicularly through the two components 12, 13. Depending on the current intensity, the contact area between the two components 12, 13 is heated as a result of resistance heating. The electrical voltage 17 is controlled such that the temperature in the contact area between the two components 12, 13 does not exceed a predetermined temperature threshold 21. The two components 12, 13 are formed as metal sheets and have a melting point of approximately 1,530°C. To ensure that the two components 12, 13 are not welded in this area, but merely adhered to one another, the temperature threshold 21 is below the melting point of approximately 1,530°C of the two components 12, 13.This means that no welding nugget is formed in the area of ​​the contact point due to resistance heating.

[0050] Due to the resistance heating, a heat flow occurs in the intermediate layer 14. Due to this heat flow, the material of the displaced intermediate layer 14 is thermally destroyed in a first region 18 of the displaced intermediate layer 14, namely in the region directly adjacent to the joint 15, to such an extent that the material in this region loses its flowability. Therefore, even after the pressing tool is opened or the compressive force 16 is released, there is no undesired backflow of the intermediate layer 14 in the region of the joint 15.

[0051] Figure 1b shows the area of ​​joint 15. Figure 1bAbove, the various regions 18, 19, 20 of the displaced intermediate layer 14 around the joint 15 are shown. In the region of the joint 15, the material of the intermediate layer 14 is completely displaced. Due to the resistance heating and the resulting heat flow through the material of the displaced intermediate layer 14, this material is thermally destroyed in a first region 18 to such an extent that it has lost its flowability. The second region 19 of the displaced intermediate layer 14 adjoins the first region 18. In this region, the material of the intermediate layer 14 is only thermally influenced. In the remaining region, the third region 20 of the displaced intermediate layer 14, as well as in the region of the non-displaced intermediate layer 14, the material of the intermediate layer 14 is not damaged or influenced.

[0052] In the Figure 1bIn the example shown, pressure means 26, 27 were used to prepare the joints such that only one recess 25 is arranged in the second component 13. In this area, for example, the second component 11 can be arranged and connected, for example, welded, to the first component 10. In Figure 1b a bolt 23 connected to the first component 10 is shown as the second component 11. The bolt 23 is thus arranged in the recess 25. On the opposite outer surface of the first component 10, namely in the area of ​​the surface of the second component 13, a suitable pressure means 26 (not shown) was used for this purpose. Figure 1b shown) maintain a flat outer surface of the first component 10.

[0053] The maximum width 42 of the joint 15 is greater than the maximum width 43 of the second component 11, namely the bolt 23.

[0054] In the Figures 2a to 2dthe process step d) for connecting the first component 10 with a second component 11 in the area of ​​the prepared joint 15 is shown. In Figure 2a It shows how a flat, second component 11 in the form of a sheet metal is welded to the first component 10 in the region of the joint 15. A weld nugget 30 is formed in the region of the contact point between the first component 10 and the second component 11. An adhesive layer 31 is arranged between the two flat components 10, 11. The adhesive layer 31 can, for example, be applied in a bead-like or band-like manner to one or both surfaces of the component(s) 10, 11.

[0055] With arc stud welding, pin-shaped parts, for example, studs 23, can be joined or connected to the flat first component 10 at the prepared joint 15. The arc can be ignited by a capacitance ignition or a drawn arc ignition. A welding rectifier or converter, welding transformer, or capacitor can be used as the energy source. The welding current ranges from 100 A to 10,000 A. The welding time can be from 10 ms to 2,000 ms. The material of the pin-shaped second component 11, for example, the stud 23, can be steel or chromium-nickel steel. The second component 11 can be bare metal, galvanized, or have similar corrosion-inhibiting coatings. Furthermore, depending on the application, the second component 11 can be oiled or have an applied layer of oil.A pin-shaped second component 11, for example, a bolt 23, typically has a diameter between 1 mm and 14 mm. This diameter typically ranges between 3 mm and 8 mm. The length of a pin-shaped second component 11, for example, a bolt 23, can be between 1 mm and 100 mm. The pin-shaped second component 11, for example, the bolt 23, can have an external thread and / or an internal thread in certain regions or over its entire length.

[0056] In Figures 2b to 2d the second component 11 is designed as a functional element, in particular as a connecting element. Figure 2bThe second component 11, namely the connecting means, is designed as a bolt 23. The bolt 23 is welded to the surface of the first component 10 in the area of ​​the prepared joint 15 by means of arc welding. The welding process can be carried out under a protective gas atmosphere 32 by providing a ceramic ring 33 around the bolt 23.

[0057] Figure 2cshows a second component 11, wherein the second component 11 is designed as a nut 22, namely as a projection nut. The nut 22 is placed onto the surface of the first component 10 in the region of the joint 15 with a circumferential projection 22a arranged on the end face. The projection 22a can be designed as a ring or segment projection. Using a suitable welding device, the nut 22 is welded onto the surface of the first component 10 in the region of the joint 15. For this purpose, a welding electrode 35 can, for example, have a centering pin 37. A recess can be provided in the region of the joint 15 to accommodate the centering pin 37.

[0058] In Figure 2d the second component 11 is designed as an annular connecting element, for example an annular nut 22. In contrast to the arrangements in Figures 2a to 2c will be in Figure 2dThe second component 11 is connected to the first component 10 not by means of a thermal joining process, but by means of a mechanical joining process. Before connecting the first component 10 to the second component 11, a hole 24 is formed through the first component 10 in the region of the joint 15. The hole 24 can be formed by drilling or punching. The second component 11 is inserted into the hole 24 in the region of the joint 15 and clamped to the first component 10 by means of suitable pressure means 26, 27.

[0059] In Figures 3a to 3c Different forms of pressure means 26, 27 are shown for carrying out the process steps a) to c). The pressure means 26, 27 can in particular have different pressure surfaces 28. In Figure 3aBoth pressure means 26, 27 have convex pressure surfaces 28. As a result, both surfaces of the first component 10 are pressed in during preparation of the joint 15, so that recesses 25 are created.

[0060] In Figure 3b a pressure means 26 has a flat or level pressure surface 28. This ensures that a surface of the first component 10 continues to maintain a flat or level surface after preparation of the joint 15. Alternatively, both pressure means 26, 27 could also have flat pressure surfaces 28. This could result in a joint, as in Figure 2c shown, are generated.

[0061] In Figure 3c Roller-shaped pressure means 26, 27 are shown. Using such roller-shaped pressure means 26, 27, a web-like joint 15 can be arranged or prepared on the first component 10.

[0062] Figure 4shows a device 200 for joint preparation. The method steps a) to c) for preparing the joint 15 can be carried out with one device 200 or several or different devices. For this purpose, the device 200 has pressing tools, for example pressure means 26, 27, for heating and displacing the intermediate layer 14. For example, a welding system can be equipped with heating elements 29 in the electrodes 35, 36 for this purpose. The desired temperature at the pressure means 26, 27 can be regulated by means of thermocouples 39 that are also provided. The temperature-controlled pressure means 26, 27 are possible with all designs of conventional resistance welding systems, for example C-shaped tongs, X-shaped tongs, machine tongs, stationary and gantry systems. Water cooling of the electrodes can be dispensed with.By providing short process times, particularly for step c) when applying the electrical voltage 17 to adhere the two components 12, 13 to one another, the service life of the pressure means 26, 27 designed as electrode caps can be increased. Furthermore, the device 200 can have cooling holes 41 for heat dissipation. Temperature signals can be processed by means of a controller 38. Independent of welding parameters, environmental influences, cycle times, and operating conditions, the desired temperature can be set by controlling compressed air valves 40 and heating elements 29.

[0063] When designing the device 200, for example, a resistance spot welding gun, the temperature profile between the pressure means 26, 27 and the base body, for example, the gun base body, can be influenced by the targeted use of copper alloys and chromium-nickel steels. The heat flow from a heating element 29 to the pressure means 26, 27, for example, the electrode cap, is promoted by components made of copper alloys (e.g., CuCr1Zr or CuNiSiCr). The heat flow from the heating element 29 into the base body of the device 200 and into other temperature-sensitive components of the device 200 can be reduced by components (e.g., the electrode arms of a resistance spot welding gun) made of a relatively poorly heat-conducting chromium-nickel steel. Furthermore, the use of ceramic insulating plates in this area is conceivable in order to conduct as little heat as possible from the pressure means 26, 27 to the base body of the device 200.For example, an insulating plate can be arranged between the pressure means 26, 27 and the base body of the device 200.

[0064] The device 200 can also be used for method step d) for connecting the first component to a second component in the region of the joint 15 prepared in steps a) to c). List of reference symbols

[0065] 100Component assembly 200Device for joint preparation 10First component 11Second component 12First component of the first component 13Second component of the first component 14Intermediate layer 15Joint 16Compressive force 17Electrical voltage 18First area of ​​the displaced intermediary layer 19Second area of ​​the displaced intermediary layer 20Third area of ​​the displaced intermediary layer 21Temperature threshold 22Nut 22aProtrusion 23Bolt 24Hole 25Recess 26First pressure element 27Second pressure element 28Pressure surface 29Heating element 30Welding nugget 31Adhesive layer 32Shielding gas 33Ceramic ring 34Arc 35First welding electrode 36Second welding electrode 37Centering pin 38Regulator 39Thermocouple 40Compressed air valve 41Cooling hole 42Maximum width of the joining area 43Maximum width of the second component

Claims

1. Method for joining a first component (10) to a second component (11) at a joint (15) of the first component (10), the first component (10) having at least a flat first component (12), a flat second component (13) and a plastics-material-containing intermediate layer (14) arranged at least in regions between the two components (12, 13), the method comprising the following steps: a) heating the first component (12) and / or the second component (13) in the region of the joint (15); and b) exerting a compressive force (16) on the first component (12) and / or the second component (13) in the region of the joint (15) until the intermediate layer (14) has been displaced in the region of the joint (15) between the first component (12) and the second component (13) and contact is established between the first component (12) and the second component (13) in the region of the joint (15); and c) applying an electrical voltage (17) to the first component (12) and the second component (13) in the region of the joint (15) until the first component (12) and the second component adhere to one another in the region of the joint (15); and d) connecting the first component (10) to the second component (11) in the region of the joint (15); characterized in that during step c) a temperature in the contact region between the first component (12) and the second component (13) does not rise above a predetermined temperature threshold (21), the temperature threshold (21) being less than the melting point of a material of the first component (12) and less than the melting point of a material of the second component (13), method steps a) to c) being referred to as method steps for joint preparation, step d) comprising a subsequent joining process between the first multilayer component (10) and a further component, namely the second component (11).

2. Method according to claim 1, characterized in that the predetermined temperature threshold (21) is less than 1600°C, preferably less than 1530°C, particularly preferably less than 1500°C.

3. Method according to either claim 1 or claim 2, characterized in that in step c) the electrical voltage (17) is applied until the intermediate layer (14) is thermally destroyed due to heating in a first region (18) adjacent to the joint (15) caused by an electrical current flow, such that the intermediate layer (14) is no longer flowable even after cooling in this first region (18).

4. Method according to any of the preceding claims, characterized in that in step b) it is detected when the contact between the first component (12) and the second component (13) in the region of the joint (15) is established in order to apply the electrical voltage (17) in step c).

5. Method according to claim 4, characterized in that the detection of the contact between the first component (12) and the second component (13) is carried out by means of a test voltage applied to the two components (12, 13) and / or by means of distance measurement.

6. Method according to any of the preceding claims, characterized in that steps a) to c) are carried out continuously along a predetermined line of the first component (10) in order to form the joint (15) in a web shape.

7. Method according to any of the preceding claims, characterized in that in step b) the compressive force (16) is exerted on the first component (12) such that on a surface of the first component (12) in the region of the joint (15) a recess (25) is created, and the compressive force (16) is exerted on the second component (13) such that a flat face remains on a surface of the second component (13) in the region of the joint (15).

8. Method according to any of the preceding claims, characterized in that in step d) the second component (11) is connected to the first component (10) by welding in the region of the joint (15) of the first component (10).