Pen for transferring solder paste from a reservoir to contact points on a circuit board, method for producing such a pen and use of such a pen in a method for repairing circuit boards

Abstract

The invention relates to a pen (2) for transferring solder paste from a reservoir to a contact point of a circuit board, wherein the pen (2) comprises: a rod-shaped element (210) having a rotation axis (RA) in the longitudinal direction; a solder application punch (220) which is composed of a base body (221) having an end face and a pin (222) protruding from the end face, wherein the solder application punch (220) has a longitudinal axis (LAI) and is arranged on the end area of ​​the rod-shaped element (210) so that the longitudinal axis (LAI) of the base body (221) is located on the extension of the rotation axis (RA) of the rod-shaped element (210), wherein the pin (222) has a longitudinal axis (LAI) and a longitudinal axis (LAI) of the base body (221). The invention relates to a stylus (2) having a first end region and a second end region, wherein the stylus (222) has a first end region and a second end region, wherein the stylus (222) has a first end region and a second end region, wherein the stylus (222) has a second end region and a second end region, wherein the second end region ..., wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region, wherein the second end region has a second end region,

Description

Technical Field

[0001] The invention relates to a pen for transferring solder paste from a reservoir to a contact point of a circuit board. The invention also includes a method for producing the pen according to the invention and the use of the pen in a method for repairing a circuit board having at least one defective component. Background Art

[0002] Different methods for assembling circuit boards are known from circuit board manufacturing. For example, so-called SMD components (surface mounted devices) are mounted on contact surfaces on the front side of the circuit board. THT components (through-hole technology) have connecting metal wires that pass through openings in the circuit board and are fastened to the opposite sides of the circuit board. Mixed assembly with SMD and THT components is also possible here. The soldering of SMD components is usually achieved with a reflow process. In order to prepare for this, the circuit board is provided with solder paste that forms a solder paste mass at the location to be assembled. Then, the component is positioned on the corresponding solder mass. The circuit board assembled in this way is subjected to a heat source, for example, it is placed on a heating plate or conveyed to a soldering furnace, wherein the solder paste is melted and thereby a connection is established between the component and the circuit board.

[0003] It may happen that a component is defective or fails during operation. In particular, in the case of expensive components or assemblies with a large number of components, the entire assembly is not discarded, but the defective or defective component is replaced. Previously, defective components mounted on a circuit board were desoldered by a thermal process. Replacement or resoldering is also carried out by means of a thermal process.

[0004] The company "ZEVAC" sells a machine that can remove components by means of a process called "milling". This process offers the possibility of removing electronic components from circuit boards by means of a milling process, thereby avoiding thermal processes. In this process, the milling head is lowered to the height of the component and then moves the milling head in the xy direction until the entire component has been milled away. As a result, the circuit board is subjected to less thermal stress, thereby preventing artificial aging.

[0005] The disadvantages of milling in the xy feed direction, such as tearing off the contact pads of the circuit board or smearing of solder, are eliminated by the method disclosed in the patent application of the applicant, entitled "Method for removing a component applied to a circuit board", filed on the same filing date. This application describes the milling of solder connections through the component in the z direction, whereby the contact pads of the circuit board are not subjected to load.

[0006] After the component is removed, a new component is applied to the exposed solder joint. In addition to the conventional methods known for this purpose, the method known from patent application DE 10 2013 112 348 A1 has proven to be particularly advantageous. In this case, a pen with a solder application punch is used. The solder paste is transferred to the contact point of the circuit board by the solder application punch so that a solder paste spot with a diameter of 10 μm to 300 μm can be produced.

[0007] However, it has been found that when using such solder application punches, volume fluctuations of the delivered solder paste volume occur, ie the delivered solder paste volume fluctuates to a greater or lesser extent. Summary of the invention

[0008] It is therefore an object of the present invention to specify a solder application pen having a solder application punch which is able to transfer solder paste with greater repetition accuracy.

[0009] This object is achieved by a pen according to the invention for transferring solder paste from a reservoir to a contact point of a circuit board. In addition, this object is achieved by a method for producing a pen according to the invention and by using a pen according to the invention in a method for repairing a circuit board having at least one defective component.

[0010] Regarding the pen setup, the pen includes:

[0011] - a rod-shaped element having an axis of rotation in the longitudinal direction;

[0012] a solder application punch consisting of a base body with an end face and a pin protruding from the end face, wherein the solder application punch has a longitudinal axis and is arranged on the end region of the rod-shaped element such that the longitudinal axis of the base body is located in extension of the axis of rotation of the rod-shaped element,

[0013] wherein the pin has a longitudinal axis and is arranged such that the longitudinal axis of the pin is located in the extension of the axis of rotation of the rod-shaped element,

[0014] The end face is designed rotationally symmetrically with respect to the longitudinal axis of the pin, and

[0015] The pin has a protruding surface at the first end region, and the protruding surface is smaller than the end surface.

[0016] According to the invention, the pin is designed to be substantially cylindrical, wherein:

[0017] The end face is designed such that the angle between the longitudinal axis of the pin and the end face is less than 180°, preferably between 60° and 120°, particularly preferably substantially 90°.

[0018] The fluctuating solder volume of the pens described in the prior art is caused by the geometry of the solder application punch. Thus, due to the manufacturing process, the solder application punch has a concave shape between the pin and the end face of the base body. The solder bead contained in the solder paste cannot adhere correctly to this concave shape. Depending on the diameter of the solder bead, the solder bead adheres more or less due to adhesion forces.

[0019] According to the solution of the invention, the concave transition area or transition surface between the pin and the end face is replaced by a transition area with a defined angle between the pin and the end face. Here, the end face is more or less bent in order to establish the angle. In the case of an angle of less than 180°, the solder bead is supported at at least two points by adhesion, regardless of its diameter. This results in that, when the pen is first immersed in a solder reservoir, such as a dipping tank, the transition area is filled with a single layer of solder beads or a circle of solder beads. After the solder paste is transferred, the solder beads remain in this area. Due to the so-called squeezing effect, the first two printed solder paste balls (also called spots) sometimes still fluctuate in terms of solder paste volume. However, the volume subsequently transferred is constant.

[0020] The other geometries of the pen correspond to those known from the prior art. The pen according to the invention enables the transfer of solder paste in order to produce a solder paste ball with a diameter of 10 μm to 300 μm, depending on the size of the lead and the front region of the base body and the solder paste used.

[0021] For example, it is provided that the ratio of the end face to the projection surface corresponds at most to a factor of 10, preferably 7.5, particularly preferably 5. The maximum distance between the end face and the projection surface, i.e. the visible length of the lead, is in the range of 50 to 250 μm, preferably 80 to 150 μm. Advantageously, the projection surface has a diameter in the range of 180 to 300 μm, preferably 130 to 180 μm, particularly preferably 50 to 130 μm.

[0022] According to a preferred embodiment of the pen according to the invention, it is provided that the base body has a square cross section orthogonal to the axis of rotation of the rod-shaped element.

[0023] According to an alternative embodiment of the pen according to the invention, it is provided that the base body has a circular cross section orthogonally to the axis of rotation of the rod-shaped element.

[0024] According to an advantageous embodiment of the pen according to the invention, it is provided that the base body is coated, wherein the end faces and the pins of the base body are uncoated. Thus, the surface of the base body is coated except for the end faces. The coating is selected such that it prevents the adhesion of solder paste. Thus, after immersion in the solder reservoir, only the end faces and the pins of the base body are covered with solder paste. The coating is in particular a hydrophobic plasma coating or a nano coating.

[0025] According to a preferred embodiment of the pen according to the invention, it is provided that the rod-shaped element and the base body are a common, one-piece component.

[0026] According to an alternative preferred design of the pen according to the invention, the rod-shaped element and the base body are connected to each other in a form-locking and / or material-locking manner. The rod-shaped element and the base body are thus two independent components. They are connected to each other, for example, by welding, soldering, gluing or plugging into each other.

[0027] According to a preferred development of the pen according to the invention, it is provided that the pen consists of two half shells in addition to the pin, which can be connected along the longitudinal axis, wherein the pin has a fastening element at a first end region, and wherein the base body has a socket for fastening the pin after the half shells have been joined together, and wherein the geometry of the socket essentially corresponds to the geometry of the fastening element. The pen consists of two half shells, more precisely regardless of whether the rod-shaped element and the base body are designed as one-piece or multi-piece. The socket is used to allow the first end region of the pin to be inserted. After the half shells have been joined together, the pin is mechanically fixed in the socket, so that no gluing or welding is required. However, this can also be performed in addition as an additional safety step.

[0028] According to an advantageous design of the pen according to the invention, the fastening element is designed in the axial direction of the pin as a wedge, a cylinder or a combination of a wedge and a cylinder. This ensures that the fastening element is clamped in the socket. Alternatively, other geometric shapes can be used. What is common to all geometric shapes is that the fastening element must have a larger cross section than the remaining radial cross section of the pin in order to ensure that the fastening element is anchored in the socket.

[0029] In relation to the manufacturing method, the method comprises:

[0030] - providing a rod-shaped element;

[0031] - placing the base body on the end region of the rod-shaped element, or machining the end region of the rod-shaped element to form the base body;

[0032] - provide pins; and

[0033] - Fasten the pins to the base.

[0034] The pens known from the prior art have a solder application punch manufactured in one piece. Here, the base body is processed by a milling tool, thereby forming the pen. Due to the geometry of the milling tool, the transition area between the pin and the end face of the base body is designed to be concave.

[0035] The pen according to the invention is provided that the pin and the matrix are separate elements which are joined together in the manufacturing method. Only in this way can an abrupt transition in an angled manner between the pin and the end face be achieved.

[0036] If necessary, a further method step is performed in which the pin is shortened to a suitable or desired length. This relates to the part of the pin that protrudes from the base body.

[0037] According to a first variant of the method according to the invention, it is provided that a hole is produced along the axis of rotation of the base body, and that the pin is inserted into the hole and bonded to the base body.

[0038] According to an advantageous embodiment of a first variant of the method according to the invention, it is provided that the hole is produced by means of laser drilling or by means of mechanical drilling. Alternatively, any other method that allows holes of the same dimensions as the pins can be used.

[0039] According to a second variant of the method according to the invention, it is provided that the fastening region of the pin is inserted into the socket and the half shells are placed one on top of the other and connected to one another in a form-fitting and / or materially bonded manner. The form-fitting connection is, for example, a screw connection.

[0040] According to an advantageous embodiment of the second variant of the method according to the invention, it is provided that the half shells are connected to one another by means of welding or soldering. Alternatively, it is provided that any other method is used which enables the half shells to be joined together.

[0041] With regard to the use, it is provided that the defective component is mechanically and / or electrically connected to the printed circuit board via at least one printed circuit board-side contact point, wherein the method in which the stylus according to the invention is used comprises at least the following steps:

[0042] - Removing defective components from circuit boards;

[0043] - Cleaning the contact points on at least one circuit board side;

[0044] - applying solder paste to the cleaned contact points on at least one circuit board side by means of a pen, wherein firstly in a wetting step a solder application punch of the pen is at least partially placed into a reservoir with solder paste for wetting with the solder paste, and then in a transfer step the wetted solder application punch is placed on the desired contact points on the circuit board side, so that the solder paste can be applied or transferred to the at least one circuit board side contact point;

[0045] - assembling the circuit board with replacement components intended for the defective component;

[0046] - Weld on replacement components.

[0047] The pen is therefore provided for use in a method as described in detail in patent application DE 10 2013 112 348 A1. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The invention is explained in more detail with reference to the following drawings, in which:

[0049] Figure 1 shows a schematic diagram of a solder application punch known from the prior art;

[0050] Figure 2 A schematic diagram showing a bottom view of a solder application punch known from the prior art;

[0051] Figure 3 Sketch showing the disadvantages resulting from solder application punches known from the prior art;

[0052] Figure 4 shows a schematic diagram of a pen according to the present invention;

[0053] Figure 5 A schematic diagram showing a bottom view of a first variant of the pen according to the invention;

[0054] Figure 6 A schematic diagram showing a bottom view of a second variant of the pen according to the invention;

[0055] Figure 7 a sketch showing the advantages provided by a pen according to the invention; and

[0056] FIG. 8 shows a schematic diagram of a method for replacing a defective component on a circuit board, in which a pen according to the invention is used. DETAILED DESCRIPTION

[0057] Figure 1 A schematic diagram of a solder application punch 120 known from pens disclosed in the prior art is shown. Such a pen 1 is disclosed, for example, in patent application DE 10 2013 112 348 A1. In addition to a rod-shaped element (not shown here) on which the solder application punch is fastened, the pen also has the solder application punch 120 itself, which comprises a solder application punch having an end face A S The base 121 of the pin 122 is S Protruding, the pin has a convex surface A V The protruding surface is preferably substantially parallel to the end surface A of the base body 121. S The pin 122 is configured so that the pin is S and convex surface A VThere is an at least sectionally concave contour K in between. When the solder application punch is placed or brought into the reservoir 6 , the solder application punch 120 receives the solder paste via the concave contour K.

[0058] The protruding surface A of the pin 122 V To the end surface A of the substrate 121 S The maximum distance D is in the range of 50 to 400 μm, preferably in the range of 80 to 150 μm. A maximum distance of approximately 300 μm has proven to be particularly suitable.

[0059] The maximum distance D is selected so that when the solder application punch 5 is placed in the solder reservoir so as to protrude from the surface A S When the end surface A of the substrate 121 touches the bottom of the solder reservoir, S Wetting with solder paste 4. For example, an immersion tank having a depth in the range of 700 μm to 400 μm, preferably in the range of 400 μm to 200 μm, particularly preferably in the range of 200 μm to 40 μm, can be used as a solder reservoir.

[0060] Figure 2 A schematic diagram showing a bottom view of the solder application punch 120. End Face A S Here, the cross section is square. However, other geometric shapes, such as a circular cross section, are also conceivable. The pin 122 and thus also the raised surface A S The pins 121 are designed so that they have a circular cross section. The cross-sectional area of ​​the pins 121 is measured from the end face A to the S Towards convex surface A V In addition to a circular cross section, other geometric shapes are also conceivable, in particular rectangular or square cross-sectional shapes.

[0061] The cross-sectional area of ​​the substantially square base 121 is 0.16 mm 2 Up to 0.64mm 2 In the range of 0.64 mm, preferably 2 Up to 1mm 2 In the range of 1 mm, preferably 2 Up to 2.25mm 2 The area within the range.

[0062] Depending on the contact area to be wetted, the convex surface A V The diameter is in the range of 300 to 180 μm, preferably in the range of 180 to 130 μm, and particularly preferably in the range of 130 to 50 μm.

[0063] also, Figure 1The solder application punch 120 shown includes a hydrophobic coating B applied to at least a portion of the surface of the substrate 121. Figure 1 As can be seen in FIG. 1 , the base body, at least in the region adjacent to the projection, is provided with a hydrophobic coating B. The hydrophobic coating B can extend over the entire base body 121 further to the side of the base body 121 facing away from the end face.

[0064] Figure 3 One of the disadvantages of the pen 1 known from the prior art is summarized. When the solder application punch 120 is sunk into the magazine, solder paste accumulates on the end face A. S and pin 122. The solder paste is composed of a plurality of small solder beads LK. The solder beads LK touch the end surface A at one point on their surface. S or pin 122, and only very poorly adheres to the corresponding surface. Because the size of the solder beads is different, the solder beads sometimes adhere better and sometimes worse to the corresponding surface. In addition, the solder beads on the end surface A S The distribution on the pin 122 is different in each dipping process.

[0065] Therefore, it is different for each printing process, such as Figure 3 As shown in the graph below. The graph shows a test of different printing processes. The number of respective printings is shown on the abscissa. The diameter of the solder paste mass produced during the respective printing is shown on the ordinate. As can be seen from the graph, the diameter of the printed solder paste mass fluctuates greatly from one printing to another. Reproducible printing results cannot be achieved by using such a solder application punch 120. The manufacture of such a solder application punch 120 is also very complicated.

[0066] Figure 4 A schematic diagram of a pen 2 according to the invention is shown. The basic dimensions of the pen correspond to Figure 1 The dimensions of the pen 1 shown are known from the prior art. The pen 2 according to the invention differs essentially from the pen 1 known from the prior art with regard to the arrangement and production of the pin 222. The pin 222 is not made from the base body 221, but is a separate component added to the base body 221. For this purpose, for example, a hole is added to the base body 221. The hole axis extends along the rotation axis RA of the rod-shaped element 210 or the longitudinal axis LA1 of the base body 221, which is located in the extension of the rotation axis RA. The pin 222 is then inserted and glued. The longitudinal axis LA2 of the pin 222 is thus located in the extension of the rotation axis RA or on the longitudinal axis LA1 of the base body 221. In Figure 4 This variant is not shown in FIG.

[0067] like Figure 4As shown, another variant is that the pen 2, more precisely the rod-shaped element 210 and the base body 221 are respectively composed of two half shells HS1, HS2. Advantageously, the base body 221 and the rod-shaped element 210 are already connected to each other in a form-locking or material-locking manner, so that only two half shells HS1, HS2 are required in total.

[0068] The pin 222 is inserted into the half shells HS1, HS2, and then the half shells HS1, HS2 are fixedly connected to each other, for example by brazing or welding. The pin 222 is hooked in the half shell and thus fastened. This is achieved by providing the pin 222 with an end region in the form of a fastening element 223, which is enlarged relative to the radial cross section of the pin 222. For example, the fastening element 223 is designed in a trapezoidal or cylindrical shape, or in a mixture of the two. The half shell has a bracket 224 corresponding to the shape and size of the fastening element 223.

[0069] The fastening element 223 is placed in the socket 224. By closing the half shells, the fastening element is fixed in the socket 224, so that the pin 222 is fixedly arranged on the base body 221. Optionally, the fastening element 223 can also be glued in the socket 224.

[0070] Both variants are characterized in that the pin 222 and the end face A z The transition between the end face A and the end face B is abrupt, that is, an angle α is formed. In the current example, the angle is substantially 90°. However, it can also be provided that the end face A z From the transition point to the pin 222, it continuously rises or falls, that is, the end region of the base body is designed to be conical or inverted conical. Thus, the angle can also be within the range of 0<α<90° or 90°<α<180°.

[0071] Figure 5 A schematic diagram of a bottom view of a first variant of a solder application punch 120 is shown. S The cross section is square in shape here. However, other geometric shapes, such as a circular cross section, are also conceivable. The pin 122 and thus also the raised surface A S They are configured so that they have a circular cross section. In addition to a circular cross section, other geometric shapes, in particular rectangular or square cross-sectional shapes, are also conceivable. In addition, the two half shells HS1 , HS2 constituting the rod-shaped element 210 and the base body 221 can be seen.

[0072] Figure 6 A schematic diagram of a bottom view of a second variant of the solder application punch 120 is shown. SHere, the cross section of the rod-shaped element 210 is substantially square. In this variant, the cross section of the pin 222 and the base body 221 can also have different shapes, such as square or round.

[0073] The advantage of this pen 2 is the simplified manufacture of the pen 2. Another important advantage of the pen according to the invention is that Figure 7 It shows:

[0074] When the solder application punch 220 is sunk into the solder reservoir, solder paste accumulates on the end surface A. S and pin 122. The solder paste is composed of a plurality of small solder beads LK. A layer of solder beads LK touches the end surface A at each point on its surface. S and pin 122. Therefore, each solder bead of this layer has two points that touch the solder application punch. As a result, the adhesion of the solder bead LK of this layer is relatively high. The solder bead of this layer only appears in the pen 2 according to the present invention, which has pin 222 and end face A. z An angle α is formed between them. After printing the solder paste, the solder beads LK of this layer still exist. Due to this single layer of solder beads, additional solder beads LK always accumulate on the solder application punch 220 in a similar pattern when sinking into the material magazine.

[0075] As from Figure 6 As can be seen in the graph of , the reproducibility of the printed solder paste balls in terms of diameter is significantly increased compared to the pen 1 described in the prior art. Due to the so-called squeeze effect, the first two printed solder paste balls sometimes fluctuate in terms of solder paste volume. However, the volume transferred subsequently is constant.

[0076] The application of the pen according to the present invention is described below:

[0077] In a first step, a defective component 6 mechanically and / or electrically fastened to a circuit board 5 via contact points 3 is removed. For example, the method disclosed in a patent application entitled "Method for removing a component applied to a circuit board" filed on the same filing date is suitable for this.

[0078] In a second step, all circuit board-side contacts 3 for connecting the defective component 6 to the circuit board 5 are cleaned. This cleaning is preferably carried out contactlessly. For this purpose, the automation system is equipped with a multi-channel cleaning nozzle. The multi-channel cleaning nozzle is in turn designed so that it can output hot air on the one hand and vacuum or air on the other hand, wherein the sucked air is guided to the filter via a bypass. The contact points 3 are traversed by means of the multi-channel cleaning nozzle, wherein the residual solder still present after the defective component 5 is removed is heated by the hot air so that it can be removed later.

[0079] In a third step, solder paste 4 is applied to the contact points 3 on the cleaned circuit board side. For this purpose, the automation system is equipped with a solder application punch 2 according to the invention, which is used to transfer or transfer the solder paste 4 from the reservoir to the contact points 3. The solder application punch 2 is then moved above the reservoir by a positioning unit of the automation system and at least partially placed in the reservoir, thereby wetting the solder application punch 2. Here, the solder application punch 2 is placed into the reservoir only with a maximum predefined first force, for example 1N.

[0080] Subsequently, the solder application punch 2 soaked with the solder paste 4 is moved from the reservoir to the previously determined position on the circuit board 5 for setting the replacement component 7. At the determined or predefined position, the solder application punch 2 is placed on the contact part 3 on the circuit board side, such as a copper pad, so that the solder paste 4 is applied or transferred to the contact part 3. Here, the solder application punch 2 is placed on the contact part 3 with a predefined second force, such as 0.7N. The positioning unit of the automation facility moves the solder application punch 2 in a force-controlled manner, that is, the force applied when the solder application punch 52 is placed or pressed onto the contact part 3 is controlled by the positioning unit, and when the applied force exceeds the predefined (first and / or second) force, the placement process is paused or stopped.

[0081] For example, a dipping tank with a defined depth can be used as a reservoir. The solder paste 4 is introduced into the dipping tank and then the excess solder paste 4 is removed by a scraper. In this way, a reproducible amount of solder paste 4 can be achieved in the reservoir or dipping tank. In addition, the reservoir or dipping tank can have a nano coating, so as to enable easier separation of the solder paste 4.

[0082] If a plurality of contact locations 3 are to be provided with solder paste 4 , the third step is repeated accordingly a plurality of times.

[0083] In a fourth step, a replacement component 7 is provided for the defective component 6 for assembly of the printed circuit board 5 . In this case, a multi-channel annular nozzle is used, for example, to separate the replacement component 7 from a component strip and to transport it to the desired position on the printed circuit board 5 .

[0084] In the fifth step, the replacement component 7 previously placed on the circuit board 5 is soldered on. Here, the replacement component 7 placed on the preheated circuit board 5 is soldered on the circuit board 5 by the hot air function of the multi-channel annular nozzle.

[0085] FIG8 shows a schematic diagram for illustrating the method flow. Figure 8a ) shows a circuit board 5 having three components, wherein the component 6 on the left is defective. The defective component 6 is removed according to the first step described above. Figure 8b) shows a circuit board 5, wherein defective components 6 have been removed and the contact points 3 on the circuit board side have been cleaned. Figure 8c ) shows a circuit board 5 , wherein solder paste 4 has been applied to the contact locations 3 . Figure 8d ) shows a circuit board 1 with a soldered replacement component 7.

[0086] Reference numerals list

[0087] 1, 2 pens

[0088] 210 Rod-shaped element

[0089] 120, 220 Solder application punch

[0090] 121, 221 matrix

[0091] 122, 222 pins

[0092] 223 Fastening elements

[0093] 224 Bracket

[0094] 3 Contact points

[0095] 4 Solder Paste

[0096] 5 Circuit Board

[0097] 6 Defective components

[0098] 7 Alternative components

[0099] A S End face

[0100] A V Raised Face

[0101] B coating

[0102] D pin length or A S To A V Maximum spacing

[0103] HS1, HS2 half shell

[0104] K Profile

[0105] LA1 Longitudinal axis of the base body

[0106] LA2 pen longitudinal axis

[0107] LK Solder Beads

[0108] RA Rotation axis

[0109] α Angle

Claims

1. Use of a pen (2) in a method for repairing a circuit board having at least one defective component, wherein: The defective component is mechanically and / or electrically connected to the circuit board via at least one circuit board-side contact point, wherein the pen (2) comprises: - a rod-shaped element (210) having an axis of rotation (RA) in the longitudinal direction; - a solder applying punch (220) having an end surface (A S ) of the base (221) and from the end surface (A S ), wherein the solder application punch (220) has a longitudinal axis (LA1) and is arranged on the end region of the rod-shaped element (210) so that the longitudinal axis (LA1) of the base body (221) is located in the extension of the rotation axis (RA) of the rod-shaped element (210), wherein the pin (222) has a longitudinal axis (LA2) and is arranged such that the longitudinal axis (LA2) of the pin (222) is located in the extension of the rotation axis (RA) of the rod-shaped element (210), Wherein, the end surface (A S ) is designed rotationally symmetrically with respect to the longitudinal axis (LA2) of the pin (222), and The pin (222) has a convex surface (A) on the first end region. V ), and wherein the convex surface is smaller than the end surface (A S ); It is characterized in that the pin (222) is designed to be basically cylindrical, and the end surface (A S ) is designed so that the longitudinal axis (LA2) of the pin (222) and the end surface (A S ) is less than 180°, Wherein, the method at least comprises the following steps: - removing the defective component from the circuit board; - cleaning the contact points on the at least one circuit board side; - applying solder paste to the cleaned contact points on the at least one circuit board side by means of a pen (2), wherein firstly, in a wetting step, a solder application punch (220) of the pen (2) is at least partially placed in a reservoir containing solder paste for wetting with the solder paste, and then in a transfer step, the wetted solder application punch (220) is placed on the desired contact points on the circuit board side, so that the solder paste can be applied or transferred to the contact points on the at least one circuit board side; - assembling the circuit board with a replacement component intended for the defective component; - Welding on the replacement component.

2. The use according to claim 1, wherein: The base body (221) has a square cross section orthogonal to the rotation axis (RA) of the rod-shaped element (210).

3. The use according to claim 1, wherein: The base body (221) has a circular cross section orthogonal to the rotation axis (RA) of the rod-shaped element (210).

4. The use according to any one of claims 1 to 3, wherein: The substrate (221) is coated, and wherein the end surface (A) of the substrate (221) S ) and the pin (222) are uncoated.

5. The use according to any one of claims 1 to 3, wherein: The rod-shaped element (210) and the base body (221) are a common one-piece component.

6. The use according to any one of claims 1 to 3, wherein: The rod-shaped element (210) and the base body (221) are connected to one another in a form-fitting and / or materially bonded manner.

7. The use according to any one of claims 1 to 3, wherein: The pen (2) consists of two half shells (HS1, HS2) in addition to the pin (222), which can be connected along the rotation axis (RA), wherein the pin (222) has a fastening element (223) on the second end area, and wherein the base (221) has a bracket (224) for fastening the pin (222) after the half shells (HS1, HS2) are joined together, and wherein the geometry of the bracket (224) substantially corresponds to the geometry of the fastening element (223).

8. The use according to claim 7, wherein: The fastening element (223) is designed to be wedge-shaped, cylindrical, or a combination of wedge-shaped and cylindrical in the axial direction of the pin (222).

9. The use according to any one of claims 1 to 3, wherein: The end surface (A S ) is designed so that the longitudinal axis (LA2) of the pin (222) and the end surface (A S ) is between 60° and 120°.

10. The use according to any one of claims 1 to 3, wherein: The end surface (A S ) is designed so that the longitudinal axis (LA2) of the pin (222) and the end surface (A S ) is substantially 90°.

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