SOLDERING TIP FOR A SOLDERING IRON

Description

[0001] The invention relates to a method for manufacturing a disc with an electrical connection element using a soldering iron with a soldering tip.

[0002] Window panes, especially vehicle windows, are often equipped with electrically conductive structures. Examples of such conductive structures include printed heating elements or antennas. To connect to the required voltage source or transmitting or receiving unit, electrical connection elements are typically soldered onto an area of ​​the conductive structure, which are connected or connectable to an electrical connection cable.

[0003] A variety of different types of terminal elements are known. US 6249966 B1, US 2007 / 0224842 A1, and WO2013 / 182394 A1 disclose terminal elements designed as push buttons. These terminal elements have the advantage of a convenient and reversible connection to the connecting cable. Typically, the male push button is soldered to the disk, and the female push button is provided with the connecting cable. The male and female push buttons can be easily connected to each other as intended to establish the electrical contact. WO2013 / 182394 A1 also discloses a method for manufacturing a disk with an electrical terminal element, wherein an electrically conductive structure is applied to a substrate, a terminal element is placed on the electrically conductive structure with a solder compound, and the terminal element is soldered to the electrically conductive structure.The preamble of claim 1 is based on WO2013 / 182394 A1.

[0004] WO 2014 / 040773 A1 discloses a terminal element crimped around the connecting cable, wherein the crimp is soldered directly onto the conductive structure.

[0005] Soldering the connection elements can be automated using soldering robots. Alternatively, the connection elements can also be soldered manually, which is particularly economical in low-wage countries and for smaller production runs. Manual soldering uses adjustable or non-adjustable soldering irons, typically equipped with interchangeable tips. The soldering tip is brought into contact with the connection element, whereupon it transfers the heat generated by the soldering iron through the connection element to the solder, which is thereby melted. Soldering tips must have high thermal conductivity and are typically made of copper. Common soldering tips are chisel-shaped with an elongated, tapered end for contacting the connection element. Stick electrodes with a flat end for contacting the connection element are also commonly used as soldering tips.

[0006] When hand soldering, it is essential to ensure that the soldering tip maintains good and, if possible, large-area contact with the connection element to guarantee efficient energy transfer. This places high demands on the technician's meticulous work. Furthermore, hand soldering often requires the connection element to be manually fixed to ensure its stable positioning. This is due to the very limited energy input with conventional soldering tips, which require a very high energy input to melt all the solder. The solder mass must therefore be heated intensely and subsequently solidifies only rather slowly, so that the connection element essentially floats on the solder and can shift its position.

[0007] The present invention is based on the objective of providing an improved method for manufacturing a disc with an electrical connection element, carried out with an improved soldering tip for a soldering iron, in particular a hand-held soldering iron. The soldering tip is intended, in particular, to ensure a more homogeneous energy input, to enable more convenient soldering, and to eliminate the need for separate fixing of the connection element during the soldering process.

[0008] The problem is solved according to the invention by a method according to independent claim 1. Preferred embodiments are described in the dependent claims.

[0009] The improved soldering tip for a soldering iron is designed for soldering an electrical connection element to an electrically conductive structure on a substrate, particularly a glass window pane. The soldering tip includes an end section at the end furthest from the soldering iron, which is intended for contact with the material being soldered, especially the connection element, during the soldering process.

[0010] According to the invention, the end section is essentially hemispherical. This enables efficient and simplified manual soldering of suitable connection elements, particularly those with a central recess. The hemispherical end section can be inserted into the recess, ensuring that a large area of ​​the connection element—namely, the area surrounding the recess—is reproducibly brought into contact with the soldering tip. This results in efficient and homogeneous energy input, leading to uniform melting of the solder. The hemispherical shape of the soldering tip's end section also simplifies soldering because less care is required regarding the soldering iron's position. The soldering iron can be held perpendicular to the substrate or at an angle—the hemispherical shape guarantees a reproducible contact area between the soldering tip and the connection element.

[0011] The soldering iron is equipped with heating elements to heat the soldering tip. The temperature is transferred from the soldering tip to the solder, which is thereby melted. This type of soldering iron is also known in technical jargon as a "hot iron".

[0012] The soldering iron in question is advantageously a handheld model. The improved soldering tip demonstrates its benefits particularly in manual soldering. In this case, the precise angle of the soldering iron is not entirely reproducible, which is compensated for by the contact area between the soldering tip and the terminal, independent of the angle of attack. However, the soldering tip requires very precise local positioning relative to the terminal to ensure complete contact. Tolerances regarding the positioning of the terminal can be easily compensated for in manual soldering, allowing the soldering tip to be positioned with the required accuracy relative to the terminal. In automated soldering, the position of the soldering tip is generally fixed, making the necessary adjustment to the exact position of the terminal within the limits of manufacturing tolerances more difficult.

[0013] The soldering tip is preferably a replaceable soldering tip for a soldering iron. Such a soldering tip can be conceptually divided into three sections: an end section for contacting the soldering material, a connection section for connecting the soldering tip to the soldering iron, a middle section extending between the end section and the connection section.

[0014] The design of the connection section is essentially determined by the type of soldering iron with which the soldering tip is to be used and therefore must be compatible. In principle, many connection systems are conceivable. Examples include plug connections, where the end section is inserted into a hole in the soldering iron and held in place, for example, by a magnet; bayonet connections; and screw connections, where the end section is threaded or has holes through which fastening screws can be inserted.

[0015] In a preferred embodiment, the connection section is wider than the central section, allowing the soldering tip to be attached to the soldering iron by means of a locking nut. The locking nut is screwed onto the soldering iron, which must, of course, be threaded, and presses the widened connection section against the soldering iron, thus securely fixing the soldering tip. The connection section preferably has a flat contact surface on the side facing away from the central section, which is brought into contact with a corresponding flat contact surface on the soldering iron. The contact surfaces of the soldering tip connection section and the soldering iron connection section are preferably congruent and aligned. However, with the use of a suitable locking nut, it is also possible to make the contact surface of the soldering tip smaller than the contact surface of the soldering iron.The widening of the connection section compared to the central section is preferably at least 1 mm, particularly preferably at least 2 mm, to ensure a stable connection to the soldering iron.

[0016] In a further preferred embodiment, the end section of the soldering tip is suitable for insertion (plugging into) the soldering iron. The soldering tip can be fixed in the soldering iron, for example, with a screw inserted laterally. In a preferred embodiment, the end section has the same width as the middle section.

[0017] The central section is preferably designed in the form of a vertical circular cylinder because this shape is common for soldering tips and because the cross-section of the central section corresponds to the cross-section of the hemispherical end section, thus ensuring optimal matching of the shapes, especially if the circular cylinder has the same radius as the hemispherical end section. In principle, however, other shapes for the central section are also conceivable, for example, with a square, rectangular, triangular, or polygonal cross-section.

[0018] The middle section can be straight or angled.

[0019] The soldering tip should have high thermal conductivity. It preferably contains copper and is ideally made of copper or a copper-containing alloy, such as brass or bronze alloys, for example, nickel silver or constantan. Copper has high conductivity and is relatively inexpensive. However, other metals or alloys are also suitable materials for the soldering tip.

[0020] The soldering tip can be coated to optimize its properties. This means that the core material of the soldering tip, preferably copper, does not come into contact with the solder, but rather the coating, which can therefore also be called the contact layer or wetting layer. The contact layer forms the outer surface of the soldering tip.

[0021] In an advantageous embodiment, the soldering tip is nickel-plated, meaning it has a nickel-based contact layer, preferably consisting entirely of nickel. The nickel contact coating slows down the heat transfer from the soldering tip to the workpiece. This prevents scaling of the soldering tip, which can occur particularly when using copper. The thickness of the nickel layer is preferably from 5 µm to 30 µm, and more preferably from 10 µm to 15 µm.

[0022] In an alternative embodiment, the soldering tip is hard-chrome plated. For the purposes of this invention, hard-chrome plating refers to a contact layer based on chromium, preferably chromium, with a thickness of at least 1 µm. The chromium contact layer preferably has a thickness of 10 µm to 80 µm, and particularly preferably 20 µm to 50 µm. A further layer, for example a nickel layer with a thickness of 5 µm to 15 µm, can be arranged below the chromium contact layer. The hard-chrome plating increases the surface hardness and, in particular, the surface tension of the soldering tip, thus preventing unwanted wetting of the soldering tip by uncontrolled solder flow.

[0023] The geometric dimensions of the soldering tip depend in particular on the design of the soldering iron used and the desired soldering tip temperature, and can be selected by a skilled person according to the requirements of the intended application. The overall length of the soldering tip is, for example, from 10 mm to 120 mm, preferably from 15 mm to 90 mm, and particularly from 15 mm to 60 mm. Such a soldering tip is easy to handle and heats up sufficiently quickly and efficiently, even at the end.

[0024] The radius of the hemispherical end section (which also corresponds to the length and width of the end section) is, for example, from 1 mm to 20 mm, preferably from 3 mm to 15 mm, and particularly preferably from 4 mm to 10 mm. The width of the middle section is preferably in the same range and is particularly preferably equal to the radius of the end section. The length of the middle section is generally limited only by handling and the thermal conductivity of the soldering tip material. It is, for example, from 1 mm to 100 mm, preferably from 5 mm to 80 mm. The width of the connection section depends on the soldering iron used and is, for example, from 1 mm to 30 mm, preferably from 4 mm to 20 mm. In an advantageous embodiment, the width of the connection section corresponds to the width of the connection surface of the soldering iron.The length of the connection section is preferably from 1 mm to 10 mm, particularly from 1 mm to 5 mm in the flange-type connection variant with a widened connection section. The length of the connection section is preferably from 10 mm to 100 mm, particularly from 20 mm to 80 mm in the connection variant with a plug-in connection section.

[0025] The improved soldering tip is suitable for a soldering iron, especially a handheld soldering iron, that can be connected to a power source. The improved soldering tip is also particularly suitable for a soldering station, comprising a soldering iron equipped with the improved soldering tip and a control unit connected to it via a cable and connectable to a power source.

[0026] The inventive method for manufacturing a disk with an electrical connection element comprises the following steps (a) Providing a substrate, (b) Applying an electrically conductive structure to an area of ​​the substrate, (c) Arranging a solder mass on an area of ​​the electrically conductive structure and an electrical connection element on the solder mass, (d) Soldering the connection element using a soldering iron with the improved soldering tip.

[0027] The soldering iron is specifically a hand-held soldering iron, used to manually solder the connecting element.

[0028] A major advantage of the improved soldering tip lies in its highly homogeneous energy input, ensured by the reliable contact of the areas surrounding the recess of the connection element. This results in a lower overall energy input required to melt the entire solder mass. Consequently, the solder mass operates at a lower temperature and cools more quickly to its solidification temperature. This prevents the connection element from shifting on the molten solder, eliminating the need for additional fixation measures required in conventional soldering processes, such as clamping or gluing. In a preferred embodiment, such additional fixation measures are omitted entirely, and no measures other than the contact pressure of the soldering tip are used to secure the connection element.This significantly simplifies the soldering process and makes it more economical. Furthermore, so-called "cold solder joints" can be avoided, as these occur when there is insufficient bonding between the materials.

[0029] The manufactured disc is preferably a glass disc, especially preferably a window disc, in particular a vehicle disc.

[0030] The connecting element must also be connected to a connecting cable, which can be done before, during, or after the method according to the invention. The connecting cable is designed to electrically connect the electrically conductive structure to an external functional element, for example, a power supply or a receiving device. For this purpose, the connecting cable is preferably routed away from the disc, starting from the connecting element and extending over the side edges of the disc. In principle, the connecting cable can be any type of connecting cable known to those skilled in the art for electrically contacting an electrically conductive structure. In addition to an electrically conductive core (inner conductor), the connecting cable can comprise an insulating, preferably polymeric, sheathing, wherein the insulating sheathing is preferably removed at the end of the connecting cable to allow an electrically conductive connection between the connecting element and the inner conductor.

[0031] The substrate preferably contains glass, particularly soda-lime glass, as is common for window panes. However, the substrate can also contain other types of glass, such as quartz glass or borosilicate glass, or polymers, especially transparent polymers, such as polycarbonate or polymethyl methacrylate.

[0032] The substrate is preferably transparent or translucent. The substrate preferably has a thickness of 0.5 mm to 25 mm, particularly preferably 1 mm to 10 mm, and most preferably 1.5 mm to 5 mm.

[0033] In a preferred embodiment, the electrically conductive structure is formed as a baked-on printing paste. The printing paste preferably contains metallic particles, in particular silver particles, and glass frits. The printing paste can be applied to the substrate in the desired shape by various printing processes, preferably screen printing, and then baked on. Printed conductive structures are common in the field of vehicle glazing, for example as heating elements, antennas, or busbars ( Busbars A current busbar is in contact with another conductive structure, for example, a transparent heating coating, heating conductors, or thin-film electrodes, and is designed to supply it with electrical current or to draw current from it. The layer thickness of the printed structure is preferably from 5 µm to 40 µm.

[0034] The electrically conductive structure is alternatively configured as an electrically conductive film, preferably copper foil or copper-containing foil. Conductive structures in the form of foil strips are common in the field of vehicle and architectural glazing, as well as in photovoltaics, particularly as busbars, or as so-called foil conductors or flat conductors. Typically, heating wires, transparent heating coatings, or thin-film surface electrodes are electrically contacted by means of these films. The film can be provided with a coating, for example, silver-plated or tin-plated. The film preferably has a thickness of 10 µm to 500 µm, and particularly preferably a thickness of 30 µm to 200 µm.

[0035] The improved soldering tip is particularly advantageous when soldering certain connection elements. These connection elements all have a central depression. This refers to a depression on the side of the connection element facing away from the substrate, which is located approximately in the center when viewed from above. The depression can also extend from the center to side edges, for example, two opposing side edges, of the connection element.

[0036] The recess is surrounded by raised areas of the connector, either completely or partially, with the raised parts, for example, bordering two opposite sides of the recess. In any case, raised parts, sections, or areas of the connector border the central recess. The hemispherical end section can be partially inserted into the recess. This means that a portion of the end section is inserted into the recess, while the remaining portion stays outside. The soldering tip is thus brought into contact with the raised parts of the connector surrounding the recess. For this to occur, the width of the soldering tip must, of course, be greater than the lateral dimensions of the recess to be able to contact the surrounding parts.Furthermore, the recess must have a minimum depth to allow the end section to be inserted sufficiently into the recess and not to touch the bottom of the recess before contacting the raised areas of the connection element. The minimum depth depends on the radius of the soldering tip's end section. The required minimum depth can be easily determined by a person skilled in the art, in accordance with the invention. The person skilled in the art can then select the soldering tip accordingly, based on the connection elements to be soldered, or conversely, design the connection elements based on the soldering tip.

[0037] The hemispherical shape of the soldering tip's end ensures reliable contact with the surrounding parts of the connection element, regardless of the angle at which the soldering iron is held to the substrate. This is particularly advantageous for hand soldering, where significant tolerances regarding this angle are inherently present.

[0038] In a preferred embodiment, the connecting element is designed as a male push button. Such a male push button has a central recess that is surrounded, typically completely, by a raised area. The recess and the surrounding area are typically round in plan view, but other shapes are also conceivable. It is also possible for the surrounding raised area to be interrupted.

[0039] The design of the connection element as a push button allows for convenient connection of the conductive structure to the electrical system at the point of use: the required connecting cable can be connected to the complementary female push button, which can then simply be plugged onto the male push button at the point of use.

[0040] In another preferred embodiment, the connection element is formed as a B-crimp around the connecting cable. The connection element is typically a metal strip or plate crimped around the connecting cable. A crimp connection is simple, cost-effective, and quick to produce and is easily automated. Complex additional process steps, such as soldering or welding the connection element to the connecting cable, can be avoided. At the same time, a very stable connection between the connection element and the connecting cable is provided.

[0041] The crimped section of the connector (the so-called crimp, i.e., the area deformed by the crimping process) is soldered directly to the electrically conductive structure. This distinguishes the connector from those that are also crimped to the connecting cable but, in addition to the crimp, include a further section specifically designed for soldering. By designing the entire connector as a crimp, it can be manufactured with advantageously small dimensions, thus reducing the space required for the electrical contact.

[0042] In an advantageous embodiment, the connection element is crimped around the electrically conductive core of the connecting cable along its entire length. The connection element is then designed entirely as a crimp and consists only of the crimped section, which is advantageous in terms of material savings. However, in addition to the section crimped around the electrically conductive core (the so-called wire crimp or conductor crimp), the connection element can have one or more further sections. Such an additional section can, for example, be crimped around the insulating sheath of the connecting cable (insulation crimp), thereby achieving a more stable connection between the connection element and the connecting cable. The connection element can also, for example, have short end sections that are not crimped.

[0043] The crimped area of ​​the connector is connected to the electrically conductive structure via the solder. This refers to a direct, mechanical connection between the crimped area of ​​the connector and the electrically conductive structure via the solder. This means that solder is placed between the crimp and the electrically conductive structure, thereby permanently and securely fixing the crimp to the conductive structure.

[0044] Preferably, the solder mass is not in direct contact with the electrically conductive core of the connecting cable.

[0045] Crimp connections are typically characterized by their cross-section perpendicular to the direction of expansion of the connecting cable. The crimp shape is determined by the choice of crimping tool. One of the crimping tool's working points can create a characteristic crimp structure, with the so-called crimp base typically located opposite this structure. The crimp shape is named according to this characteristic crimp structure. The preferred crimp shape within the scope of the present invention is the so-called B-crimp. The two bent side edges are inserted into the connecting cable, resulting in the shape of two arcs opposite a preferably flat crimp base, thus forming the eponymous "B" shape.

[0046] The geometric dimensions of the crimp (crimp height, crimp width, crimp length) can be appropriately selected taking into account the diameter of the connecting cable and common standards.

[0047] The terminal element is soldered to the electrically conductive structure via the crimp base, with the characteristic crimp pattern facing away from the substrate and solder. The required central recess is formed by the terminal element's side edges, which are inserted into the connecting cable. The soldering tip can be partially inserted into this recess. The B-shaped curves form the surrounding raised areas that come into contact with the soldering tip. In this case, the central recess extends the entire crimp length between two opposing side edges of the terminal element, while being surrounded on both sides by the adjacent raised areas.

[0048] The invention is not limited to specific materials for the connection element. Typical connection elements are made of copper, which ensures high electrical conductivity. However, the connection element can also be made of other materials whose coefficient of thermal expansion is better suited to the substrate, for example, titanium or stainless steel if the substrate is made of glass. This reduces thermal stresses during soldering. In a preferred embodiment, the difference in the coefficients of thermal expansion between the substrate and the connection element is less than 5 x 10⁻⁶ / °C.

[0049] Typical material thicknesses of the connecting element range from 0.1 mm to 4 mm, preferably from 0.3 mm to 1 mm. The length and width of the connecting element range, for example, from 5 mm to 30 mm.

[0050] The invention is not limited to the use of a specific solder compound, but can be implemented with all solder compounds. The invention is equally suitable for conventional lead-based solder compounds as well as for lead-free solder compounds, which are gaining increasing importance, particularly in the automotive sector. The solder layer thickness is preferably less than or equal to 0.6 mm.

[0051] The solder compound can be placed on the conductive structure, and then the connection element can be arranged on the solder compound. In a preferred embodiment, however, the connection element is first coated with the solder compound and then arranged on the conductive structure together with the solder compound. This offers process advantages because the connection elements can be prepared in large quantities with the portioned solder compound. The solder compound is preferably applied to the connection element as a platelet or flattened droplet with a defined layer thickness, volume, and shape. The layer thickness of the solder compound platelet is preferably less than or equal to 0.6 mm. The shape of the solder compound platelet is preferably determined by the shape of the contact surface of the connection element.

[0052] The improved soldering tip is particularly useful for soldering an electrical connection element onto an electrically conductive structure on a substrate, preferably a window pane, especially a vehicle window with heating or antenna function.

[0053] A disc manufactured according to the invention is used in buildings or in means of transport for traffic on land, in the air or on water, in particular in rail vehicles or motor vehicles, preferably as a windshield, rear window, side window and / or roof window, in particular as a heated disc or as a disc with antenna function.

[0054] The invention is explained in more detail with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way. It shows: Fig. 1 a perspective view of one embodiment of the improved soldering tip, Fig. 2 a cross-section through the soldering tip according to Figure 1 Fig. 3 shows a cross-section through the further development of the improved soldering tip, Fig. 4 shows a soldering station using the soldering tip according to Figure 1 Fig. 5 shows a cross-section through a preferred connection element for soldering with the improved soldering tip, Fig. 6 shows a cross-section through a disk with the connection element according to Figure 5 during the method according to the invention, Fig. 7 shows a cross-section through a disk with a further preferred connecting element during the method according to the invention and Fig. 8 shows a flow diagram of an embodiment of the method according to the invention.

[0055] Fig. 1 and Fig. 2Each figure shows a detail of an improved soldering tip 1 for a soldering iron, in particular a hand-held soldering iron. The soldering tip is formed in one piece, but can be conceptually divided into three sections: an end section 2, a middle section 3, and a connecting section 4.

[0056] The end section 2 serves to make contact with the solder joint during soldering. According to the invention, the end section 2 is designed in the form of a hemisphere.

[0057] The middle section 3 connects to the end section 2. The middle section 3 is formed in the form of a vertical circular cylinder with the same radius as the hemispherical shape of the end section 2.

[0058] The connecting section 4 adjoins the central section 3. Connecting section 4 is also shaped like a vertical circular cylinder. However, connecting section 4 is wider than central section 3, meaning it has a larger radius. Connecting section 4 thus forms a kind of projection. The end section 4 serves to connect the soldering tip 1 to the intended...

[0059] Soldering iron. The surface of the connecting section 4 facing away from the central section 3 is flat and circular and can be flange-mounted to a corresponding connecting surface of the soldering iron. The connecting surface of the soldering iron preferably has the same shape and size as the surface of the connecting section 4, i.e., it is essentially congruent. The connection is preferably made with a cap nut that presses the end section 4 against the soldering iron and is secured there by means of a thread. Alternatively, it is also possible, for example, to fasten the end section 4 to the soldering iron using screws that pass through the projection.

[0060] In this embodiment, the length of the central section 3 is preferably from 5 mm to 80 mm, particularly from 10 mm to 50 mm. The length of the connecting section 4 is preferably from 1 mm to 10 mm, particularly from 1 mm to 5 mm.

[0061] The hemispherical shape of end section 2, for example, has a radius of 4 mm, as does the cylindrical shape of middle section 3. Middle section 3 has a length of 43 mm. Connecting section 4 has a length of 3 mm, and its cylindrical shape has a radius of 6 mm. This results in a total length of soldering tip 1 of 50 mm.

[0062] Soldering tip 1 is made of copper, ensuring good thermal conductivity. It is hard-chrome plated – coated with a single layer of chromium approximately 30 µm thick. This increases surface hardness and reduces wear. Furthermore, solder cannot adhere to the tip, as is undesirably the case when using non-hard-chrome plated copper. This reduces the risk of damage to the solder joint from adhering solder when removing the tip after soldering.

[0063] The soldering tip 1 can alternatively be nickel-plated or have other coatings. This affects its adhesive properties.

[0064] Fig. 3Figure 1 shows a further embodiment of the improved soldering tip 1, which is connected to the soldering iron via a plug connection. For this purpose, the connecting section 4 is inserted into a corresponding receptacle on the soldering iron and secured, for example, with a screw inserted from the side. The connecting section 4 and the central section 3 have the same dimensions and the same cross-section. Central section 3 and connecting section 4 thus form a continuous, cylindrical extension onto the hemispherical end section 2, which is only conceptually divided into central section 3 and connecting section 4 by the fact that the connecting section is inserted into the soldering iron and the central section protrudes from the soldering iron when assembled.

[0065] In this embodiment, the length of the central section 3 is preferably from 1 mm to 50 mm, particularly from 3 mm to 20 mm. The length of the connecting section 4 is preferably from 10 mm to 100 mm, particularly from 20 mm to 80 mm.

[0066] Fig. 4Figure 1 shows a soldering station using the improved soldering tip 1. The soldering tip 1 is mounted on a conventional hand soldering iron 5. For this purpose, the connection section 4 is positioned on a congruent connection surface of the soldering iron 5. The soldering tip 1 is fixed there by means of a cap nut 6, which is screwed onto a thread of the soldering iron 5. The soldering iron 5 is equipped with a heating cartridge to heat the soldering tip 1 to the temperature required for soldering. The soldering iron 4 is connected via an electrical cable 8 to a control unit 7, which can be used to activate and deactivate the heating function and to regulate the heating power. The control unit 7 is in turn connected to a power source via a cable (not shown).

[0067] The improved soldering tip 1 can, in principle, be used with any available soldering iron 5. Only the connection area 4 of the soldering tip 1 needs to be adapted to the respective soldering iron 5 so that the soldering tip 1 can be mounted on the soldering iron 5.

[0068] As an alternative to the adjustable soldering station shown, it is also possible to use the soldering tip 1 on a non-adjustable soldering iron whose heating power cannot be adjusted by the user.

[0069] Fig. 5 Figure 1 shows a cross-section through an electrical connection element, preferably to be soldered with the improved soldering tip 1, in a perspective view. The connection element is designed as a male push button. The push button is essentially designed in the form of a hollow cylinder, i.e., it has a central recess in plan view, which is surrounded by a raised, round area.

[0070] The connector is made of copper or stainless steel, for example. It may have coatings, such as a silver plating to improve electrical conductivity. The material thickness is approximately 0.3 mm. The round solder pad on the underside of the connector has a diameter of approximately 8 mm. The hollow cylinder forming the actual push button has an inner diameter of approximately 3 mm, an outer diameter of approximately 5.7 mm, and a height of approximately 3.5 mm.

[0071] The connector is designed and suitable for connection to a female push button (not shown) by simply pushing it onto the button. A connecting cable is attached to the female push button. This allows for a very simple and convenient electrical connection between the connector and an external power source at the point of use.

[0072] Fig. 6 shows a cross-section through a disk with the electrical connection element 12 made of Figure 5during the soldering process according to the invention. The pane is, for example, a rear window of a passenger car and comprises a substrate 1, which is a 3 mm thick thermally tempered single-pane safety glass made of soda-lime glass. An electrically conductive structure 11 in the form of a heating conductor structure is printed onto the substrate 10. The electrically conductive structure 11 contains silver particles and glass frits. In the edge region of the pane, the electrically conductive structure 11 is widened to a width of approximately 10 mm and forms a contact surface for the electrical connection element 12. The connection element 12 serves to electrically connect the electrically conductive structure 11 to an external power supply via a connecting cable (not shown). The electrical contact is concealed from an observer outside the passenger car by a screen-printed cover between the electrically conductive structure 11 and the substrate 10.

[0073] The connecting element 12 is to be connected to the electrically conductive structure 11 via a solder compound 13. For this purpose, the solder compound 13 is placed between the conductive structure 11 and the connecting element 12 and melted using the soldering tip 1. The soldering tip 1 is brought into contact with the connecting element 12, through which the necessary heat energy is introduced into the solder compound 13. The end section 2 of the soldering tip 1 is partially inserted into the central recess of the connecting element 12. Since the soldering tip 1 has a larger diameter than the recess, it is not fully inserted into the recess. Instead, the edge region of the end section 2 of the soldering tip 1 is in contact with the areas of the connecting element surrounding the recess, i.e., in this case, the upper edge of the hollow cylinder forming the push button.Naturally, the recess must have a minimum depth that depends on the radius of the end section of the soldering tip 1, so that the soldering tip can be lowered sufficiently to establish the desired contact between soldering tip 1 and connection element 12.

[0074] The advantage of the improved soldering tip 1 is immediately apparent from the illustration. Due to the hemispherical shape of the end section 2, the illustrated contact between the soldering tip 1 and the connection element 12 is always achieved, regardless of the angle of the soldering tip 1 relative to the substrate 10. When soldering by hand, the technician does not need to maintain a precise angle of attack or, for example, hold the soldering iron exactly perpendicular to the substrate 10. This significantly simplifies the process. Furthermore, the energy is transferred very homogeneously into the solder mass 13 via the circular contact surface, meaning that less energy is required to melt it than with a localized, decentralized energy input.The solder mass 13 is therefore heated to a lesser degree overall and solidifies more quickly after the energy supply ceases, so that unwanted displacement of the connecting element 12 on the still liquid solder mass 13 can be avoided even without further fixing measures. The positional accuracy of the connecting element 12 on the substrate 10 can thus be increased, and manufacturing tolerances reduced. These are significant advantages of the present invention.

[0075] Fig. 7Figure 1 shows a cross-section through a disk with an alternative preferred embodiment of the electrical connection element 12 during the soldering process according to the invention. The connection element 12 is designed as a so-called B-crimp – it consists of a metal plate with a material thickness of, for example, 0.4 mm, such as a copper or stainless steel plate, which is bent around an end section of a connecting cable 14 and permanently and stably connected to the connecting cable 14 by crimping. The designation "B-crimp" results from the characteristic shape of the connection element 12, which is formed by inserting the bent side edges of the connection element 12 into the connecting cable 14.The characteristic crimp shape shows two rounded structures (arcs) in profile, resembling the letter "B". The connecting cable 14 is designed as a stranded wire conductor, the individual strands of which extend evenly to both sides of the contact interior, resulting in advantageous stability and gas tightness of the crimp contact. The crimp base forms the contact surface with the solder 13, while the characteristic crimp structure, in the form of a double arc, faces away from the substrate 10. The characteristic crimp structure forms a central recess into which the end section 2 of the soldering tip 1 is partially inserted. The soldering tip 1 thus comes into contact with the areas surrounding the recess on the two arcs.

[0076] In this embodiment, the recess of the connecting element 12 is not surrounded by adjacent areas, but extends over the entire length of the connecting element 12. The recess is bounded on two sides by the raised arches.

[0077] The length of the connecting element 12 is, for example, 4.5 mm (crimp length), the width (crimp width) is about 2.5 mm and the height is about 1.5 mm (crimp height).

[0078] Fig. 8 Figure 1 shows an embodiment of the inventive method for producing a disc with an electrical connection element 12 using the improved soldering tip 1. Examples

[0079] Connection elements in the form of snap fasteners were used ( Fig. 5 , Fig. 6The terminal elements were soldered to a glass plate using a hand-held soldering iron, firstly using an improved soldering tip and secondly using a conventional soldering chisel. The terminal elements soldered according to the invention exhibited a 100% stable solder joint, whereas the conventionally soldered terminal elements did not adhere to the silver print (0% stable solder joint). This is due to the small contact area between the conventional chisel shape and the push button, resulting in low energy input. In contrast, the improved hemispherical soldering tip provides efficient energy input, effectively melting the solder and stably soldering the terminal element.

[0080] Furthermore, connection elements in the form of a B-crimp ( Fig. 7The terminals were soldered using a hand-held soldering iron with a silver print on a glass plate, firstly using an improved soldering tip and secondly using a conventional soldering chisel. The terminals soldered according to the invention exhibited a 100% clean solder joint. In contrast, uncontrolled flow of solder was observed in approximately 50% of the conventionally soldered terminals, causing the solder to come into undesirable contact with the conductive core of the connecting cable within the crimp. This is due to the significantly more homogeneous energy input from the improved soldering tip, which melts the solder in a more controlled manner. Reference symbol list

[0081] (1) Soldering tip (2) End section of soldering tip 1 (3) Middle section of soldering tip 1 (4) Connection section of soldering tip 1 (5) Hand soldering iron (6) Union nut (7) Control unit (8) Cable between hand soldering iron 5 and control unit 6 (10) Substrate (11) Electrically conductive structure (12) Electrical connection element (13) Solder compound (14) Connection cable of connection element 12

Claims

1. Method for producing a pane with an electrical connection element, comprising (a) providing a substrate (10), (b) applying an electrically conductive structure (11) on a region of the substrate (10), (c) arranging a soldering compound (13) on a region of the electrically conductive structure (11) and an electrical connection element (12) on the soldering compound (13), (d) soldering the connection element (12) with a soldering iron (5) having a soldering tip (1), characterized in that, the soldering tip comprises a substantially hemispherical end portion (2).

2. Method according to claim 1, wherein the soldering iron (5) is a hand-held soldering iron, with which the connection element (12) is hand soldered.

3. Method according to claim 1 or 2, wherein the substrate (10) contains glass, preferably soda lime glass, and wherein the electrically conductive structure (11) is implemented as a fired printing paste containing silver particles or as an electrically conductive foil.

4. Method according to one of claims 1 through 3, wherein the connection element (12) has a central depression, into which the end portion (2) of the soldering tip (1) is partially inserted in order to bring the soldering tip (1) into contact with the areas of the connection element (12) surrounding the depression.

5. Method according to claim 4, wherein the connection element (12) is implemented as a male snap.

6. Method according to claim 4, wherein the connection element (12) is implemented as a B crimp around a connection cable (14).

7. Method according to one of claims 1 through 6, wherein other than the contact pressure of the soldering tip (1), no further measures are taken for securing the connection element (12).

8. Method according to one of claims 1 through 7, wherein the soldering tip comprises the end portion (2), a connection portion (4), and, extending therebetween, a substantially cylindrical middle portion (3), wherein the connection portion (4) is widened compared to the middle portion (3) for securing on the soldering iron (5) by means of a union nut (6).

9. Method according to one of claims 1 through 7, wherein the soldering tip comprises the end portion (2), a connection portion (4), and, extending therebetween, a substantially cylindrical middle portion (3), wherein the connection portion (4) is suitable for being inserted for securing in the soldering iron (5).

10. Method according to one of claims 1 through 9, wherein the soldering tip contains copper.

11. Method according to one of claims 1 through 10, wherein the soldering tip is nickel plated.

12. Method according to one of claims 1 through 10, wherein the soldering tip is hard chrome plated.

13. Method according to one of claims 1 through 12, wherein the substrate (10) is a window pane, in particular a vehicle pane with a heating or antenna function.