Moving unit for moving two soldering assemblies for processing printed circuit boards and soldering system for selective wave soldering with one moving unit

Abstract

A traversing unit (17) for moving two soldering assemblies (18, 20) arranged to be movable along an x-axis and a y-axis extending perpendicular thereto for processing printed circuit boards (14), with axis drives (32, 50) for moving the soldering assemblies (18, 20) along the x-axis and / or the y-axis, wherein for each of the at least two soldering assemblies (18, 20) a separate carriage (22, 24) is provided, on which the respective soldering assembly (18, 20) can be arranged, wherein the at least two carriages (22, 24) are arranged to be movable along the x-axis or the y-axis on a common linear guide (26), that the at least two carriages (22, 24) are connected to one another by means of a coupling device (40) in such a way that when one of the carriages (22, 24) is moved by means of the axle drive (32, 50), the at least other carriage (24, 22) is moved along, characterized in that that the coupling device (40) is designed to adjust a distance (38) between the at least two carriages (22, 24)

Description

[0001] The invention relates to a traversing unit for moving two soldering assemblies arranged to be movable along an x-axis and a y-axis extending perpendicular thereto for processing printed circuit boards. For processing the printed circuit boards, the soldering assemblies can each comprise or be formed by a soldering device, in particular a solder pot with a soldering nozzle, a spray unit (fluxer), a camera, and / or a cleaning unit. Furthermore, axis drives are provided for moving the soldering assemblies along the x-axis and / or the y-axis. The invention also relates to a soldering system with such a traversing unit.

[0002] In the area of ​​contacting electronic components, which are attached, for example, using through-hole technology (THT) from the top side of a circuit board through a hole in the circuit board, it is known to contact the components from the bottom side of the circuit board.

[0003] For contacting individual pins or rows of pins by soldering, so-called selective wave soldering is known. In this process, a circuit board or a pin to be contacted is positioned precisely over a solder assembly using a soldering device that includes a standing wave of liquid solder. It is also known to first spray flux onto the pins / rows of pins to be soldered using a spray unit to improve the wetting of the solder, known as fluxing. Individual pins or rows of pins are then soldered by spot soldering.

[0004] EP 3 153 270 B1 discloses providing two soldering assemblies that can be moved independently of each other along the x-axis, y-axis, and z-axis by means of controllable actuators. While such a setup enables very flexible processing of the printed circuit boards, it is very complex to implement. In particular, absolutely synchronous processing of the soldering assemblies is technically very complex to achieve.

[0005] A traversing unit for a soldering system is known from DE 10 2004 063 488 A1 and DE 10 2004 062 866 A1. The traversing unit comprises a support that can be moved along the x-axis, on which a bridge that can be moved along the y-axis is mounted. Two soldering assemblies are located on the bridge, allowing them to be freely positioned along the x- and y-axes. The soldering assemblies can also be moved in the z-direction via adjusting devices.

[0006] Another traversing unit with axis drives for selective soldering with features of the preamble of patent claim 1 is known from US 2015 / 0 298 233 A1 or DE 10 2012 111 946 A1.

[0007] DE 10 2015 219 611 A1 discloses a soldering module for a soldering system for selective wave soldering, comprising at least a first and a second solder pot. The solder pots can be displaced along an X-axis by means of an X-axis drive, along a Y-axis by means of a Y-axis drive, and along a Z-axis by means of a Z-axis drive. The axes are each arranged orthogonally to one another. Two Y-axis drives and two displacement devices are provided, on which the solder pots can be displaced along the Y-axis by means of the Y-axis drives. A first displacement device is assigned to the first solder pot, and a second displacement device, which is different from the first displacement device, is assigned to the second solder pot.

[0008] The object of the present invention is to further develop the initially described movement unit in such a way that the printed circuit boards can be processed flexibly, while also enabling a synchronous movement of the soldering assemblies in a simple manner.

[0009] This object is achieved by a traversing unit having the features of patent claim 1.

[0010] Consequently, it is provided that a carriage is provided for each of the at least two soldering assemblies. Thus, the at least two soldering assemblies can each be arranged on a separate carriage. For processing the circuit boards, the soldering assemblies can each have or be formed by a soldering device, in particular a solder pot with a soldering nozzle, a spray unit (fluxer), a camera and / or a cleaning unit. Furthermore, the at least two carriages are arranged so as to be movable along the x-axis or the y-axis on a common linear guide, wherein the at least two carriages are connected to one another by means of a coupling device such that when one of the carriages is moved by means of an axis drive, the at least other carriage is moved along with it.By providing the coupling device, which enables a rigid connection between the two carriages, synchronous movement of the carriages along the x-axis or the y-axis is possible. This specifically ensures that only one of the carriages is directly driven by the axis drive; the other carriage is moved exclusively via the coupling device. Consequently, only one axis drive can be provided, with which both soldering assemblies—due to their coupling with the coupling device—can be moved along the x-axis or the y-axis.

[0011] The coupling device, which is provided between the two carriages, is designed to adjust the distance between the at least two carriages. Depending on the circuit boards to be processed, the two carriages, and thus the two solder assemblies, can have different distances in the x-direction and / or y-direction.

[0012] The adjustment of the coupling device can be done manually or via a drive on the coupling device side.

[0013] It is conceivable that the coupling device is designed such that the distance between the at least two carriages is adjustable during operation of the traversing unit. The coupling device can provide a controllable drive, such as an electric motor, to adjust the distance. If circuit boards of different sizes are processed consecutively during operation, the distance between the carriages, and thus the distance between the soldering assemblies, can be varied depending on the circuit board being processed.

[0014] The drive control can also be configured such that the two carriages are not moved synchronously during machining, which can be achieved by appropriately adjusting the coupling device. According to this configuration, the two carriages can be moved independently and differently in the x-direction or y-direction due to the superimposed movement of the axis drive and the drive of the coupling device.

[0015] The coupling device can comprise a rotatable spindle rod which cooperates with at least one spindle nut provided on at least one of the two carriages for adjusting the distance between the at least two carriages. By rotating the spindle rod, which can be driven, for example, by an electric motor, the distance between the two carriages then changes. The spindle rod can, for example, be rotatably mounted at one end on one carriage and at the other end on another carriage in the spindle nut; it is conceivable for the spindle rod to be mounted on both carriages by means of spindle nuts, wherein the spindle rod then provides a right-hand thread which cooperates with one nut and a left-hand thread which cooperates with the other nut.

[0016] In another embodiment, the coupling device can comprise a rack that interacts with at least one adjusting pinion provided on at least one of the two carriages to adjust the distance between the at least two carriages. The rack can, for example, be firmly attached to a carriage at one end and interact with the pinion at the other end. By rotating the pinion, which can be motor-driven, the distance between the two carriages changes.

[0017] In a further embodiment, the coupling device comprises a drivable, preferably closed, belt that interacts with the at least two carriages to adjust the distance between the at least two carriages. It is conceivable that the belt is driven via a motor-driven belt drive, so that when the belt drive is actuated, the at least two carriages are moved toward or away from each other.

[0018] It is also conceivable to provide a distance measuring device that can determine the distance between the two carriages, and thus the distance between the two soldering assemblies. Especially when a motor drive is provided to adjust the distance between the carriages, a defined distance between the two carriages can be specified via a control loop.

[0019] It is further advantageous if the coupling device comprises at least one spring element that urges one slide toward or away from at least the other slide, so that the distance between the at least two slides is adjusted against a preload of the at least one spring element. This allows for precise positioning of the two slides relative to one another.

[0020] The linear guide can be designed to include one, two, or more parallel guide rails. The rails can be spaced apart so that even larger or heavier solder assemblies can be moved safely in the x- or y-direction.

[0021] It is also advantageous if the axis drive for moving the at least one carriage is provided at the free end of the linear guide or at the free end of at least one guide rail. The drive can comprise a belt that runs within the linear guide and preferably within the guide rail and is motion-coupled to at least one carriage.

[0022] It is also conceivable for the linear guide to be mounted on a transverse guide running perpendicular to the linear guide by means of bearing elements. In particular, when the linear guide runs along the x-axis, the transverse guide runs along the y-axis. Conversely, it is conceivable that when the linear guide runs along the y-axis, the transverse guide runs along the x-axis. By superimposing the movements in the x-direction and y-direction, the two soldering assemblies can be freely positioned, particularly synchronously. If the coupling device has its own drive, at least one of the two carriages can perform a superimposed movement in the x-direction or y-direction by appropriately controlling the drive.

[0023] Depending on the linear guide, the transverse guide can comprise one, two, or more guide rails running parallel to one another. It has proven advantageous to provide three guide rails and to provide a corresponding axle drive on the central guide rail to move the linear guide along the transverse direction. The axle drive can comprise an electric motor and a closed belt driven by the electric motor, which is preferably arranged within the transverse guide or a guide rail of the transverse guide.

[0024] It is also advantageous if the soldering assemblies are each arranged on the respective carriages so that they can be moved independently of one another along a z-axis running perpendicular to the x-axis and the y-axis, and if a separately controllable z-axis drive is provided on each carriage. This allows at least two soldering assemblies to be raised or lowered independently of one another in the z-direction, i.e., in the vertical direction.

[0025] The object mentioned at the outset is also achieved by a soldering system for the selective wave soldering of printed circuit boards, wherein the printed circuit boards can be transported through the soldering device along a direction of movement running along the x-axis, and wherein the soldering system has a travel unit according to the invention for moving at least two soldering assemblies.

[0026] The object mentioned at the outset is also achieved by a method for operating a travel unit according to the invention or a soldering system according to the invention, wherein the at least two carriages with the two soldering assemblies are moved on a common linear guide along the x-axis or the y-axis and wherein the individual circuit boards are processed simultaneously by means of the two soldering assemblies.

[0027] Further details and advantageous embodiments of the invention can be found in the following description, on the basis of which an embodiment of the invention is described and explained in more detail.

[0028] They show: Fig. 1 a schematic representation of a soldering system for selective wave soldering in side view; Fig. 2 a movement unit for the wave soldering system according to Fig. 1 in isometric view; Fig. 3 the traversing unit according to Fig. 2 in a different operating position; and Fig. 4 a longitudinal section through a coupling device as shown in Fig. 2 or Fig. 3 is shown.

[0029] The Fig. The wave soldering system 10 schematically illustrated in Figure 1 comprises a device 12 for transporting a circuit board 14 populated with electronic components along a transport direction 16 extending in the direction of an x-axis. A y-axis extends perpendicular to the x-axis and perpendicular to the plane of the page. A z-axis extends perpendicular to the x-axis and the y-axis. For simplicity of illustration, the electronic components on the circuit board 14 are not shown.

[0030] The transport device 12 can, for example, comprise a chain conveyor which rotates endlessly and on which the printed circuit boards 14 are mounted and guided in the region of their longitudinal side edges in such a way that the underside of the printed circuit boards 14 is essentially freely accessible.

[0031] Below the transport device 14, a movement unit 17 is provided, which comprises two soldering assemblies 18, 20, which are arranged one behind the other in the y-direction, so that in the Fig. 1 only one of the soldering assemblies 18, 20 is visible; the rear soldering assembly 20 is covered by the front soldering assembly 18. The soldering assemblies 18, 20 are in particular soldering devices with solder pot and soldering nozzle, as shown in the Fig. 2 and Fig. 3 are shown.

[0032] The soldering assemblies 18, 20 are each arranged on their own carriage 22, with the carriages 22, 24 being movable along the y-axis on a common linear guide 26. The linear guide 26, in turn, is arranged on a transverse guide 28 for movement along the x-axis.

[0033] While the traversing unit 17 in Fig. 1 is only shown schematically, the Fig. 2 and Fig. 3 the traversing unit 17 in two different operating states.

[0034] As in the Fig. 2 and Fig. 3, the travel unit 17 comprises the transverse guide 28 with two guide rails 30 running parallel to each other. Perpendicular to the transverse guide 28, along the y-axis, the linear guide 26 is provided, which in turn has two guide rails 31.

[0035] To ensure the lowest possible friction displacement of the linear guide 26 on the transverse guide 28, bearing elements 33 can be provided between the guide rails 30 and 31. Accordingly, bearing elements 33 can be provided between the carriages 22 and 24 and the guide rails 31 of the linear guide 26. The bearing elements can, in particular, comprise rolling elements to ensure play-free yet low-friction movement of the individual components.

[0036] The guide rails 30 of the transverse guide 28, which extend along the x-axis, are preferably arranged in a stationary manner. The transverse guide 28 has two synchronously controllable axis drives 32, which are provided at the free ends of the guide rails 30 of the transverse guide 28. The axis drives 32 can provide circulating belts that run within the guide rails 30 and are coupled to the linear guide 26 or its guide rails 31, so that the linear guide 26 can be moved along the x-axis as such.

[0037] The two carriages 22, 24 are arranged on the linear guide 26 or the associated guide rails 31 so that they can move along the y-axis.

[0038] For coupling the movement of the two carriages 22, 24, a coupling device 40 is provided, which engages on the one hand on the carriage 22 and on the other hand on the carriage 24. The coupling device 40 is designed such that a distance 38 between the two carriages 22, 24 can be adjusted with it (see Fig. 4 with accompanying description). In Fig. 2, the distance 38 is set so that it is minimal or equal to zero; in Fig. 3 there is a comparatively large distance 38 of several centimeters between the two carriages 22, 24.

[0039] On each of the two carriages 22, 24, a soldering assembly 18 is provided, each comprising a solder pot 44 and a soldering nozzle 46 provided on the solder pot 44. The soldering assemblies 18 are designed such that they can be used to solder electronic components onto the circuit board 14 from below. During operation, a standing wave of liquid solder emerges from the solder nozzles 46, which is positioned by the traversing unit 17 such that the assemblies to be soldered, or the pins or pin rows to be contacted, are soldered by means of the soldering wave.

[0040] In the Fig. 1, Fig. 2 and Fig. 3, the soldering assemblies 18 comprise the respective solder pot 44 with the solder nozzle 46. It is conceivable that, in addition to or instead of the solder pot 44, spray units (fluxers) for spraying flux onto the circuit boards 14, cameras for capturing the underside of the circuit board and / or cleaning units for cleaning the underside of the circuit board before and / or after the soldering process are provided.

[0041] The arrangement of the soldering assemblies 18 on the carriages 22, 24 is such that the soldering assemblies can be moved independently of one another on the respective carriages 22, 24 along a z-axis arranged perpendicular to the y-axis and x-axis. For this purpose, suitable z-axis drives 48 are provided on the carriages 22, 24.

[0042] To move the carriages 22, 24 along the y-axis, a y-axis drive 50 is provided on at least one of the guide rails 31 of the linear guide 26. The axis drive 50 can, like the axis drives 32, have an electric motor and a closed belt that runs within the corresponding guide rail 31 and is motion-coupled to one of the two carriages 22, 24. Consequently, if the y-axis drive 50 is activated, the carriage 22, which is directly coupled to the y-axis drive 50, is driven. Due to the coupling device 40, the carriage 24 is moved synchronously when the carriage 22 is moved.

[0043] The movement of the two carriages 22, 24 in the y-direction is generally synchronous. However, it is conceivable that during the movement of one carriage 22, the distance 38 between the two carriages 22, 24 is adjusted by means of the coupling device 40, so that the carriage 24 is moved relative to the carriage 22.

[0044] In the Fig. 4 shows a conceivable coupling device 40 in longitudinal section along the y-axis with the two carriages 22, 24. In the y-direction, the two carriages 22, 24 are spaced apart by a distance of 38. The coupling device 40 has a spindle rod 54 that can be rotated by means of an electric motor 52. The spindle rod 54 has a left-hand threaded section 56 and a right-hand threaded section 58, each of which cooperates with a spindle nut 60 arranged on the respective carriage 22, 24. When the electric motor 52 is controlled, the two carriages 22 and 24 are moved towards or away from each other, depending on the direction of rotation of the electric motor 52. In order to compensate for any possible play of the components of the coupling device 40 in the y-direction, as shown in Fig. 4, a spring element 62 may be provided which urges the two carriages 22, 24 away from each other.

[0045] According to another embodiment, instead of the spindle shaft 56, the coupling device can comprise a rack that is attached to at least one of the two carriages 22, 24, wherein the rack cooperates with an adjusting pinion for adjusting the distance between the two carriages 22, 24. Furthermore, it is conceivable for the coupling device 40 to comprise a drivable belt that cooperates with the two carriages 22, 24 for their adjustment. The coupling device can also provide entirely different drive means that effect a possible adjustment.

Claims

[1] Moving unit (17) for moving two soldering assemblies (18, 20) arranged to be movable along an x-axis and a y-axis extending perpendicular thereto for processing printed circuit boards (14), with axis drives (32, 50) for moving the soldering assemblies (18, 20) along the x-axis and / or the y-axis, wherein for each of the at least two soldering assemblies (18, 20) a separate carriage (22, 24) is provided, on which the respective soldering assembly (18, 20) can be arranged, wherein the at least two carriages (22, 24) are arranged to be movable along the x-axis or the y-axis on a common linear guide (26), that the at least two carriages (22, 24) are connected to one another by means of a coupling device (40) in such a way that when one of the carriages (22, 24) is moved by means of the axle drive (32, 50), the at least other carriage (24, 22) is moved along, characterized by , that the coupling device (40) is designed to adjust a distance (38) between the at least two carriages (22, 24) [2] Moving unit (17) according to claim 1, characterized by that the coupling device (40) is arranged such that the distance (38) between the at least two carriages (22, 24) is adjustable during operation of the travel unit (17). [3] Moving unit (17) according to one of the preceding claims, characterized by that the coupling device (40) comprises a rotatable spindle rod (56) which cooperates with at least one spindle nut (60) provided on at least one of the two carriages (22, 24) for adjusting the distance (38) between the at least two carriages (22, 24). [4] Moving unit (17) according to one of claims 1 to 2, characterized bythat the coupling device (40) comprises a toothed rack which cooperates with at least one adjusting pinion provided on at least one of the two carriages (22, 24) for adjusting the distance (38) between the at least two carriages (22, 24). [5] Moving unit (17) according to one of claims 1 to 2, characterized by that the coupling device (40) comprises a drivable belt which cooperates with the at least two carriages (22, 24) for adjusting the distance (38) between the at least two carriages (22, 24). [6] Moving unit (17) according to one of the preceding claims, characterized by that the coupling device (40) comprises at least one spring element (62) which urges one carriage (22, 24) towards or away from at least the other carriage (24, 22). [7] Moving unit (17) according to one of the preceding claims, characterized bythat the linear guide (26) comprises one, two or more guide rails (31) running parallel to one another. [8] Moving unit (17) according to one of the preceding claims, characterized by that the axle drive (50) for moving the at least one carriage (22, 24) is provided at the free end of the linear guide (26). [9] Moving unit (17) according to one of the preceding claims, characterized by that the linear guide (26) is in turn mounted by means of bearing elements (33) on a transverse guide (28) running perpendicular to the linear guide (26). [10] Moving unit (17) according to claim 9, characterized by that the transverse guide (28) comprises one, two or more guide rails (30) running parallel to one another. [11] Moving unit (17) according to one of the preceding claims, characterized bythat the soldering assemblies (18, 20) are each arranged to be movable independently of one another along a z-axis running perpendicular to the x-axis and the y-axis on the respective carriages (22, 24) and that a z-axis drive (48) is provided on each carriage (22, 24). [12] Soldering system (10) for the selective wave soldering of printed circuit boards (14), wherein the printed circuit boards (14) can be transported through the soldering device along a direction of movement (16) running along the x-axis, comprising a displacement unit (17) according to one of the preceding claims. [13] Method for operating a travel unit (17) for a soldering system (10) for selective wave soldering according to claim 12, wherein the at least two carriages (22, 24) with the two soldering assemblies (18, 20) are moved on a common linear guide (26) along the x-axis or the y-axis and the individual printed circuit boards (14) are processed simultaneously by means of the two soldering assemblies (18, 20).

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