Soldering module

Abstract

Soldering module (3) for, in particular selective, soldering of components to a circuit board (14) with a soldering nozzle (37) for generating a solder wave, wherein the soldering module (3) comprises a linear conveyor (8), in particular a belt conveyor or a chain conveyor, for applying solder to the circuit board (14) by moving the circuit board (14) in a conveying direction over the solder wave, and wherein the linear conveyor (8) is tiltable about a first tilting axis, characterized in that the first tilting axis (23) extends through the solder wave.

Description

[0001] The present invention relates to a soldering module for soldering components to a circuit board, a soldering system comprising this module, and a method for soldering components to a circuit board.

[0002] The publication DE 689 15 526 T2 relates to an automatic soldering process and a corresponding device for it.

[0003] The publication DE 83 24 290 U1 relates to a soldering machine comprising several workstations in succession and containing at least one fluxer, a preheating station, a soldering station and a washing device, and having a transport device for soldering frames, which may be subdivided, on which circuit boards to be soldered are conveyed through the workstations.

[0004] The German patent application DE 10 2005 028 196 A1 relates to a device for wave soldering of workpieces, comprising a conveying system for transporting the workpieces along a conveyor track in one conveying direction and a soldering nozzle located below the conveyor track. The soldering nozzle has several solder outlet openings, the density of which changes in the conveying direction of the workpieces.

[0005] The publication DE 10 2005 046 199 A1 concerns a soldering machine and a corresponding soldering process in which protective gas is used.

[0006] Several methods have become established for the automated soldering of components to electronic circuit boards, also known as printed circuit boards. These include reflow soldering and wave soldering. Selective soldering is a variant of wave soldering.

[0007] In selective soldering, liquid solder is forced through a soldering nozzle, creating a solder wave on the nozzle's top surface. Typically, the nozzle is immersed in a solder bath, allowing the solder exiting the nozzle to flow back into the bath. There, the solder can be reheated and pumped through the nozzle.

[0008] Depending on the board layout, the circuit board, populated with components to be soldered, is either passed over the soldering wave or the soldering wave is passed underneath the board. An example of a selective soldering system is described in DE 10 2007 002 777 A1. Typically, in wave soldering, the circuit board is moved over the soldering wave at a specific, predetermined angle to control the amount of solder that adheres to the board. The selected angle always represents a compromise with regard to the requirements of the individual components.

[0009] Based on this, the present invention addresses the problem of providing a soldering module, a soldering system and a method which enable greater consideration of the soldering properties of the individual components.

[0010] According to the invention, the above problem is solved with a soldering module according to claim 1, a soldering system according to claim 16 and a soldering method according to claim 19.

[0011] With regard to the soldering module, the above-mentioned problem is solved by a soldering module for, in particular selective, soldering components to a circuit board with a soldering nozzle for generating a solder wave, wherein the soldering module comprises a linear conveyor, in particular a belt conveyor or a chain conveyor, for applying solder to the circuit board by moving the circuit board in a conveying direction over the solder wave, and the linear conveyor is tiltable.

[0012] The soldering module according to the invention is characterized in that the first tilting axis extends through the soldering shaft. This allows the linear feeder to be tilted without having to readjust the distance between the soldering nozzle and the linear feeder.

[0013] A first embodiment of the soldering module provides that the linear conveyor is tiltable about a first tilting axis, wherein the normal of the circuit board preferably forms an angle of at least 4°, preferably at least 8°, and more preferably at least 10°, with the direction of gravity. Tilting the circuit board by an angle of at least 4° can ensure a favorable amount of solder applied to the board for most applications. An angle of at least 8° can prove advantageous if the amount of solder adhering to the component and / or the time during which hot, excess solder is in thermally conductive contact with the component is to be reduced, in order to decrease the thermal stress on the component during soldering.

[0014] A first embodiment of the soldering module provides that the linear conveyor is tiltable about a first tilting axis, wherein the normal of the circuit board preferably forms an angle of at least 4°, preferably at least 8°, and more preferably at least 10°, with the direction of gravity. Tilting the circuit board by an angle of at least 4° can ensure a fair amount of solder applied to the board, which is advantageous in most applications. An angle of at least 8° can prove advantageous if the amount of solder adhering to the component and / or the time during which hot, excess solder is in thermally conductive contact with the component is to be reduced, in order to decrease the thermal stress on the component during soldering.

[0015] In another embodiment, the first tilting axis is oriented essentially perpendicular to the conveying direction or essentially parallel to the conveying direction. Orienting the first tilting axis essentially perpendicular to or parallel to the conveying direction can simplify the design of the soldering module.

[0016] Furthermore, according to a further development of the soldering module, the linear conveyor can be tilted about a second tilting axis, whereby the second tilting axis is essentially perpendicular to the direction of gravity. By providing a second tilting axis that is essentially perpendicular to the direction of gravity, the soldering result can be better adapted to the specified circuit board layout.

[0017] Another design provides that the second tilting axis extends through the soldering wave.

[0018] In another embodiment of the soldering module, the linear conveyor can be tilted while the circuit board is moving over the soldering wave. This tilting capability can reduce the circuit board's throughput time through the soldering module.

[0019] Furthermore, after further development of the soldering module, the soldering nozzle is movable in a plane essentially perpendicular to the direction of gravity. This mobility of the soldering nozzle in a plane essentially perpendicular to the direction of gravity allows components to be selectively soldered to the circuit board at different locations. The travel distance parallel and / or perpendicular to the conveying direction can be, in particular, 400 mm to 450 mm.

[0020] Another design of the soldering module allows the distance between the soldering nozzle and the circuit board to be adjusted by moving the nozzle. This adjustable distance between the nozzle and the circuit board makes it particularly possible to solder components of varying heights that are attached to the underside of the board.

[0021] In another embodiment of the soldering module, the soldering nozzle is rotatable. A rotatable, and in particular non-rotationally symmetrical, soldering nozzle can, for example, be adapted to the orientation of the tilting axis. Furthermore, continuous rotation of the soldering nozzle can reduce the risk of solder deposits on the nozzle.

[0022] Furthermore, after further training, the soldering nozzle can be wetted with solder, especially when made of steel. When using a wettable soldering nozzle, the process conditions at the soldering point can be independent of the transport direction of the components to be soldered towards the nozzle. Soldering nozzles made of simple steel are also particularly inexpensive on the market.

[0023] Another embodiment of the soldering module provides that the soldering nozzle is not wettable by solder, and is made of stainless steel, particularly coated steel. If a soldering nozzle that is not wettable by solder is used, the solder can flow off the back of the component. A soldering nozzle that is not wettable can be made of coated stainless steel.

[0024] In another embodiment, the soldering module incorporates a protective gas system. When the solder heats up, dross formation can occur. The use of a protective gas reduces the extent of oxidation on the surface of the solder pool and thus the formation of dross.

[0025] Furthermore, a solder joint preparation device is provided following a further development of the soldering module. This device includes a gas nozzle. The gas nozzle allows gas, particularly a protective gas such as nitrogen, to be blown onto the solder joint, thus better defining the solder flow direction. This prevents the formation of unwanted solder bridges between solder joints.

[0026] Another design of the soldering module includes a second soldering nozzle for generating a second soldering wave. This second nozzle can significantly reduce the circuit board's throughput time, as components can be soldered simultaneously at multiple points on the board. Alternatively, the second nozzle can be used to dispense a different solder, one specifically suited to the components being soldered. It is also conceivable to use a wettable nozzle as the first and a non-wettable nozzle as the second.

[0027] With regard to the soldering system, the aforementioned problem has been solved by the soldering system comprising a first soldering module, as described above, and a flux module. The combination of a flux module and a soldering module can reduce processing time. In particular, the flux module and the soldering module can be configured for the automatic transfer of the assembled circuit boards.

[0028] One initial design of the soldering system includes a preheating module. This module activates the flux applied to a populated circuit board. It also heats the circuit board and its components, reducing the temperature difference between the board and components on one side and the liquid solder on the other. This improves solder adhesion to both the components and the circuit board, while simultaneously reducing the risk of component damage due to thermal stress. A flux module and a preheating module can also be combined in a single preparation module. This allows for the use of a shared linear feeder, reducing costs compared to using separate modules. Conversely, separate modules can increase flexibility.

[0029] In another embodiment, the soldering system has a second soldering module, which can, for example, increase the throughput. It is also conceivable that a different soldering nozzle and / or a different solder could be used in the second soldering module. The associated advantages are described above.

[0030] With regard to the method for soldering components to a circuit board, the above-mentioned problem has been solved according to the invention in that a populated circuit board is taken up by a linear conveyor, wherein the linear conveyor is in a take-up position, that the linear conveyor is tilted into a first processing position, that the circuit board is moved by means of the linear conveyor over a first soldering wave, wherein a partial area of ​​the circuit board is wetted with solder, that the linear conveyor is tilted into a transfer position and that the circuit board is transferred in the transfer position of the linear conveyor.

[0031] The proposed method allows for the integration of soldering modules for selective soldering and corresponding soldering systems into existing production facilities without the need for manual transfer of circuit boards. Furthermore, a higher degree of automation can be ensured even in the production of more complex, customized circuit assemblies.

[0032] In this process, a soldering module and / or a soldering system as described above can be used.

[0033] The invention is explained below with reference to figures. The drawing shows examples. Fig. 1. A proposed soldering system in a first design form in a perspective view; Fig. 2. A proposed soldering system in a second embodiment in a perspective view; Fig. 3 a preparation module of a proposed soldering system; Fig. 4 a soldering module of a proposed soldering system; Fig. 5 the soldering module according to Fig. 4 in a first tilting position of the linear conveyor; Fig. 6 the soldering module according to Fig. 4 in a second tilting position of the linear conveyor; Fig. 7 the soldering module according to Fig. 4 in a first disassembled state; and Fig. 8 the soldering module according to Fig. 4 in a second disassembled state.

[0034] The in Fig. The soldering system shown in Figure 1 comprises a preparation module 2, a first soldering module 3, and a second soldering module 4. A circuit board 14 (not shown), already populated with components, is first coated with flux in the preparation module 2. Subsequently, in the preparation module 3, the flux is activated by applying heat to the circuit board 14, simultaneously introducing sufficient thermal energy into the circuit board 14 and the components for a good soldering result. The circuit board 14 is then transferred from the preparation module 2 to the first soldering module 3. The first soldering module 3 can be used, for example, to solder an initial group of components to the circuit board 14. A second soldering module 4 is provided following the first soldering module 3. The second soldering module 4 can be used to solder another group of components to the circuit board 14. The second soldering module 4 may differ from the first soldering module 3, for example, in the type of solder used.It is also conceivable that a different soldering nozzle 37 is used in the second soldering module 4, which may differ from the soldering nozzle of the first soldering module 4, for example, in its diameter or shape, and which may therefore be better suited for smaller (or larger) components. It is also conceivable to use two identical soldering modules 3 and 4 solely to increase the cycle rate.

[0035] In contrast to soldering system 1 according to Fig. 1 is at the in Fig. In the soldering system 1 shown in Figure 2, only one soldering module 3 is provided following the preparation module 2. This allows the soldering system 1 to be provided more cost-effectively. Thanks to its modular design, additional soldering modules can be added with minimal effort. Soldering system 1 can therefore be adapted cost-effectively to specific production requirements and does not need to be completely replaced.

[0036] In the Fig. 3 shows a preparation module 2 as it is used in a soldering system according to Fig. 1 or Fig. Preparation module 2 can be used. The preparation module 2 comprises a linear conveyor 8 with which a circuit board 14 can be transported through the preparation module. A flux module 9 is also provided, with which flux can be applied to the areas of the assembled circuit board to be wetted with solder. A preheating module 10 is connected to the flux module 9. The preheating module 10 can be used to activate the flux applied to the assembled circuit board 14. Furthermore, the circuit board 14 and the components can be heated to a temperature that enables a particularly good mechanical and electrical bond with the solder to be applied. The preparation module 2 can also include a control unit 11 with which the linear conveyor 8, the flux module 9, and the preheating module 10 can be controlled.Furthermore, it may be provided that the control unit 11 also controls further modules connected to the preparation module 10, in particular soldering modules.

[0037] The one in Fig. The soldering module 3 shown in section 4 has a soldering module frame 12 in which a soldering unit 13 and a linear conveyor 8 are mounted. A circuit board 14 can be moved by the linear conveyor 8 via a [missing information - likely a reference to a specific component or component] in the Fig. The soldering wave generated by the soldering unit 13 is not visible and is concealed by the soldering module frame 12. The linear conveyor 8 has two guides 15 and 16 which guide the circuit board 14 laterally. Two drives 27 and 28 are provided for moving the circuit board 14. The distance 17 between the two guides 15 and 16 can be changed by means of a motor 18 to accommodate different circuit board sizes. The linear conveyor 8 is gimbal-mounted in the soldering module frame 12 via two linear conveyor frames 19 and 20 and suspended by bearings 21 and 22.

[0038] About in the Fig. The linear conveyor 8 can be tilted about a first tilting axis 23 and a second tilting axis 24 by means of four motors (not shown). The first tilting axis 23 and the second tilting axis 24 are each oriented perpendicular to the direction of gravity. Furthermore, the first tilting axis 23 is parallel to the conveying direction 26 and the second tilting axis 24 is perpendicular to the conveying direction 26 in which the circuit board 14 is moved.

[0039] In the Fig. 5 is also the soldering module 3 according to Fig. 4 shown. As in Fig. 4 The soldering module 3 comprises a soldering module frame 12, a soldering unit 13 and a linear conveyor 8. In contrast to the one in Fig. In the soldering module 3 shown in Figure 4, the linear conveyor 8 is tilted about a first tilting axis 23 by an angle 29, such that the normal of the circuit board 14 and the direction of gravity form an angle of 7°. The first tilting axis 23 is oriented perpendicular to the direction of gravity 25 and parallel to the conveying direction 26.

[0040] Unlike the one in the Fig. Soldering module 3, shown in 5, is located in the one described in Fig. The soldering module 3 of the linear conveyor 8 shown in Figure 6 is tilted about a second tilting axis 24. The second tilting axis 24 extends perpendicular to the direction of gravity 25 and the conveying direction 26. Due to the tilting, the normal of the circuit board 14 forms an angle of 11° with the direction of gravity.

[0041] Fig. Figure 7 shows a soldering unit 13 of the soldering module 3 according to Fig. 4. The soldering unit 13 has a table 29. The table 29 is movable in a plane perpendicular to the direction of gravity 25 via rails 30, 31 or 32, 33 and motors 34, 35. A solder container 36 with a soldering nozzle 37 is provided on the table 29.

[0042] In the Fig.Figure 8 shows only the table 29 with solder container 36 of the soldering module 3. A soldering nozzle 37 is arranged in the center of the solder container 65. The solder liquefied in the solder container 36 can be pumped through the soldering nozzle 66 by means of a pump 38, so that a solder wave forms at its tip. A motor 39 is also provided, with which the solder container 65 (and the soldering nozzle 66) can be rotated about an axis aligned parallel to the direction of gravity 25. The solder container 65 (and the soldering nozzle 66) can be raised or lowered in the direction of gravity 25 by means of three spindles, of which only two spindles 40, 41 are visible. The solder container 65 can be guided by two guides 42, 43. A heating element 44 is provided above the solder container 65, which covers the solder container 65 like a lid, leaving an opening in the center for the soldering nozzle 66. The heating element 44 has two electrical connections 45.Furthermore, a solder joint preparation device is equipped with a gas nozzle 46. A protective gas, in particular nitrogen, can be supplied via a connection 47. The protective gas can be heated by the heating element 44 and blown onto the solder joint via the gas nozzle 46, thus enabling more precise solder application. The gas nozzle 46 can also be used to ensure that the solder conveyed through the soldering nozzle flows off in a controlled manner on the side opposite the gas nozzle 46. Preferably, the gas nozzle 46 is oriented against the conveying direction of a linear feeder for a circuit board.

Claims

[1] Soldering module (3) for, in particular selective, soldering of components to a circuit board (14) with a soldering nozzle (37) for generating a solder wave, wherein the soldering module (3) comprises a linear conveyor (8), in particular a belt conveyor or a chain conveyor, for applying solder to the circuit board (14) by moving the circuit board (14) in a conveying direction over the solder wave, and wherein the linear conveyor (8) is tiltable about a first tilting axis, characterized by , that the first tilting axis (23) extends through the soldering wave. [2] Soldering module (3) according to claim 1, wherein the first tilting axis (23) is oriented substantially perpendicular to the direction of gravity (25). [3] Soldering module (3) according to claim 1 or 2, wherein the linear conveyor (8) is tiltable about the first tilting axis (23) such that the normal of the circuit board (14) forms an angle of at least 4°, preferably at least 8°, more preferably at least 10°, with the direction of gravity (25). [4] Soldering module (3) according to one of the preceding claims, wherein the first tilting axis (23) is oriented substantially perpendicular to the conveying direction (26) or substantially parallel to the conveying direction (26). [5] Soldering module (3) according to one of the preceding claims, wherein the linear conveyor (8) is tiltable about a second tilting axis (24), wherein the second tilting axis (24) is oriented substantially normal to the direction of gravity (25). [6] Soldering module (3) according to claim 5, wherein the second tilting axis (24) extends through the soldering wave. [7] Soldering module (3) according to one of the preceding claims, wherein the linear conveyor (8) is tiltable during the movement of the circuit board (14) over the soldering wave. [8] Soldering module (3) according to one of the preceding claims, wherein the soldering nozzle (37) is movable in a plane oriented substantially normal to the direction of gravity (25). [9] Soldering module (3) according to one of the preceding claims, wherein the distance between the soldering nozzle (37) and the circuit board (14) is adjustable by moving the soldering nozzle (37). [10] Soldering module (3) according to one of the preceding claims, wherein the soldering nozzle (37) is rotatable. [11] Soldering module (3) according to one of the preceding claims wherein the soldering nozzle (37) is wettable by solder, in particular made of steel. [12] Soldering module (3) according to one of claims 1 to 10, wherein the soldering nozzle (37) is not wettable by solder and is in particular made of a non-rusting, coated steel. [13] Soldering module (3) according to one of the preceding claims, wherein the soldering module (3) has a protective gas device. [14] Soldering module (3) according to one of the preceding claims, wherein a solder joint preparation device is provided, the solder joint preparation device comprising a gas nozzle (46). [15] Soldering module (3) according to one of the preceding claims, wherein the soldering module (3) has a second soldering nozzle (37) for generating a second soldering wave. [16] Soldering system comprising a first soldering module (3) according to one of claims 1 to 14 and a flux module (9). [17] Soldering system according to claim 16, wherein the soldering system has a preheating module (10). [18] Soldering system according to one of claims 16 or 17, wherein the soldering system comprises a second soldering module (3) according to one of claims 1 to 14. [19] Method for soldering components to a circuit board (14) using a soldering module (3) according to one of claims 1 to 14 and / or a soldering system according to one of claims 16 to 18, characterized by, that a populated circuit board (14) is taken up by a linear conveyor (8), wherein the linear conveyor (8) is in a take-up position, that the linear conveyor (8) is tilted into a first processing position, that the circuit board (14) is moved by means of the linear conveyor (8) over a first soldering wave, wherein a partial area of ​​the circuit board (14) is wetted with solder, that the linear conveyor (8) is tilted into a transfer position and that the circuit board (14) is transferred in the transfer position of the linear conveyor (8).

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