Selective soldering system heating module having a reflector bulkhead, selective soldering system, and associated method

Abstract

The invention relates to a heating module for a selective soldering system having a reflector bulkhead, to a selective soldering system, and to an associated method.

Description

[0001] Title: Selective soldering system heating module with a

[0002] Reflector bulkhead, selective soldering system and associated process

[0003] Description

[0004] The invention relates to a selective soldering system heating module, i.e. a heating module for a selective soldering system, a selective soldering system and an associated method.

[0005] In selective soldering systems, printed circuit boards equipped with electrical or electronic components are processed in different or mixed processing modules. The modules form different zones of the selective soldering system, which can be implemented as separate assemblies. The printed circuit boards can also be designed as printed circuit boards, which contain multiple printed circuit boards that are separated into individual boards after soldering.

[0006] During selective soldering, the first step is fluxing, during which the areas of the circuit board that are to be exposed to liquid solder during the soldering process are wetted. This is followed by preheating in heating modules. The aim of preheating is to heat the circuit board homogeneously before it is transported to the soldering module, where the actual soldering process takes place. During preheating, it is advantageous to introduce up to 50 percent of the heat energy into the circuit board using infrared heat radiators, so that the circuit board and components in the soldering module are not heated up suddenly when they come into contact with the liquid solder. To solder the components, the soldering modules are equipped with solder pots that can be moved independently of one another and each generate a soldering wave. During the soldering process, the solder pot or the soldering wave is moved to the position on the circuit board where the component is ultimately to be soldered.After the soldering process, the soldered circuit board is fed to an output, whereby the output can also be the input.

[0007] Known heating modules of selective soldering systems, which are arranged between flux modules and soldering modules, have a base, a module inlet and a module outlet, wherein during operation the respective circuit board is transported along a transport direction (x-direction) from the module inlet to a heating position and from the heating position to the module outlet. The heating modules also generally have side walls running parallel to the transport direction, wherein heat radiators, in particular infrared heat radiators, are provided in or on the base. The base with the

[0008] The side walls can form a heating cassette.

[0009] Newer selective soldering systems, in particular, require a throughput height of 60 mm to 100 mm, or greater, above and below the transport level, as the size and height of the components to be soldered or those already on the circuit board are increasing—also with regard to the power electronics of electric vehicles. The throughput height is the height at which the circuit boards, with the components arranged on them, can be transported collision-free through the soldering system or heating module. The throughput height is therefore specific to the soldering system or heating module.

[0010] It has been shown that when the throughput height of a machine is, for example, 100 mm, the heating of the circuit boards in the heating position is relatively uneven and inhomogeneous due to the comparatively large distance to the heat radiators. In particular, the edge areas of the circuit boards receive less radiant energy than the central areas, which has a negative impact on the subsequent soldering behavior and thus on the overall process result.

[0011] JP H04-274 867 A discloses a reflow soldering system in which, to reduce the consumption of protective gas, lower operating costs, and easily adjust a temperature profile inside a reflow passage, adjustable partition walls are provided along a conveyor to form several chambers arranged one behind the other. Heating elements can be provided in the chambers. DE 37 24 005 C2, among other things, discloses a reflow soldering system which has heating elements and in which adjustable, elliptical reflectors are provided around the heating elements.

[0012] From DE 37 15 940 C2 an infrared soldering oven with a sliding drawer with a sliding drawer wall and a for sliding circuit boards in and out is known.

[0013] DE 10 2011 087 704 A1 discloses a reflux soldering system for flexible printed circuit boards, which features top-side openings. Several adjustable IR apertures are located at or above the opening to shade the near-infrared radiation emerging upward from the opening. The apertures define a soldering field from which the near-infrared radiation emerges to heat the flexible printed circuit board.

[0014] DE 10 2011 087 704 A1 discloses a soldering system comprising a preheating chamber and pressure chambers. The pressure chambers are sealed by means of bulkheads to generate pressure and may have their own heating device. The pressure chambers may be designed as a sintering device or a diffusion soldering device.

[0015] The present invention is based on the object of providing a heating module of a selective soldering system and a selective soldering system with a heating module, which lead to an optimized process result even with large throughput heights.

[0016] This object is achieved by a selective soldering system heating module with the features of claim 1. By adjusting the at least one reflector bulkhead to the operating position, the module inlet and / or module outlet can be closed at least in sections. The reflector bulkhead is adjustable in particular independently of any movement or transport of the circuit board. The module inlet can in particular be provided at a different location than the module outlet; however, it is also conceivable for the module inlet to also take on the function of the module outlet, i.e. for the circuit board to be transported out of the module through the module inlet, which then functions as the module outlet. By providing the at least one reflector bulkhead, the throughput height is at least temporarily reduced, which can occur in particular depending on the components to be soldered or already present on the circuit board.This ensures that, in the heating position of the circuit board, less radiant energy generated by the heat rays leaves the respective heating module. Furthermore, it can ensure that the edge areas of the circuit boards are sufficiently exposed to radiant energy, and the temperature profile in the circuit board plane becomes more homogeneous.

[0017] For example, if a soldering system or a heating module has a throughput height of 100 mm, this can be reduced to 50 mm or less by means of the at least one adjustable reflector bulkhead - if the components on the circuit board or their installation height permit it - which leads to more even heating of the circuit board and noticeable energy savings. Therefore, if components are present whose installation height is lower than the maximum permissible throughput height of the soldering system, a better soldering result can be achieved by adjusting the at least one reflector bulkhead to the operating position; even if this reduces the throughput height of the soldering system.

[0018] Preferably, the radiation emitted by the heat radiators is at least largely reflected by the at least one reflector bulkhead, so that it remains in the heating module and contributes to preheating the circuit board. Furthermore, significant energy savings can be achieved because less radiation energy leaves the heating module. Ideally, the material and surface of the reflector bulkhead are designed such that the emitted wavelengths of the radiators are optimally reflected.

[0019] It is advantageous if at least one reflector bulkhead is adjustable in a z-direction perpendicular to the ground. This has the advantage that at least the movement in the direction of gravity can be realized with little or no force input.

[0020] Furthermore, it may be advantageous if the at least one reflector bulkhead is adjustable in a y-direction running parallel to the floor. This has the advantage that the at least one reflector bulkhead can be adjusted from the side, thus requiring no vertical space above or below. In particular, this ensures that other components (heating elements, fans, filters, etc.) above and / or below the transport level are not affected.

[0021] In order to be able to move the reflector bulkhead into the operating position despite the presence of transport means that transport the respective circuit board through the soldering system, it is advantageous if at least one reflector bulkhead has, in particular, open-edged recesses for transport means running in the transport direction. This allows the module entrance and / or module exit to be at least largely closed despite the presence of the transport means.

[0022] It is also advantageous to provide two reflector bulkheads at the module inlet and / or outlet, each of which can be moved toward and away from each other. This allows the module inlet and / or outlet to be closed relatively quickly, since each of the two reflector bulkheads only has to travel half the distance compared to a single reflector bulkhead.

[0023] It has also proven advantageous to provide a drive for adjusting the at least one reflector bulkhead. The drive can be designed to be manually operated, for example, via a crank. Furthermore, the drive can be designed to be motorized, in particular via an electric motor, pneumatic motor, or pneumatic cylinder.

[0024] In the case where the drive is motorized, it is advantageous if a control system is provided which activates the drive and is set up in such a way that at least one reflector bulkhead is adjusted to the operating position depending on the installation height of the respective circuit board including the components arranged on it. This reduces the throughput height depending on the installation height of the circuit board, specifically to a value such that the circuit board including components can still be transported through the heating module or soldering system without collision. If comparatively tall components are arranged on the circuit board, a greater throughput height can be maintained; if only comparatively flat components are provided, the throughput height can be reduced to achieve better heating of the circuit boards.

[0025] It is advantageous if the control system is further configured such that the adjustment is such that, in a first operating position, the distance between at least the reflector bulkhead and the transport plane is equal to or slightly greater than the installation height of the respective circuit board. This ensures that as little heat radiation as possible escapes from the heating module.

[0026] It is particularly advantageous if the control system is further configured such that the adjustment is such that, after the respective circuit board reaches the heating position, the at least one reflector bulkhead is adjusted to a second operating position in which the module inlet and / or the module outlet is at least largely closed. Consequently, after each entry of a circuit board into the heating module, the latter can preferably be closed as largely as possible, so that as little radiation as possible escapes from the heating module during the heating phase. After preheating has ended, the at least one reflector bulkhead is adjusted to an open position so that the heated circuit board can exit the heating module and / or a circuit board to be heated can enter the heating module. The object stated at the outset is also achieved by a soldering system for soldering components present on a circuit board, comprising a heating module according to the invention.

[0027] Furthermore, the object mentioned above is also achieved by a method for operating a selective soldering system, wherein the selective soldering system comprises a heating module, wherein, when a printed circuit board is in a heating position in the heating module, the heating module is closed with an adjustable reflector bulkhead. The closing takes place at least slightly and preferably to the greatest possible extent. The heating module is preferably a heating module according to the invention.

[0028] Further advantages and advantageous embodiments of the invention can be found in the following description, which describes and explains various embodiments of the invention in more detail. In the drawings:

[0029] It shows :

[0030] Figure 1 shows a selective soldering system according to the invention in side view,

[0031] Figure 2 is an isometric view of a first heating module according to the invention,

[0032] Figure 3 shows a longitudinal section through the heating module according to Figure 3,

[0033] Figure 4 is an isometric view of a second heating module according to the invention; and Figure 5 is an isometric view of a third heating module according to the invention.

[0034] Figure 1 shows a selective soldering system 10 for the selective soldering of components present on a printed circuit board 16. The soldering system 10 has an inlet 12 and an outlet 14. Printed circuit boards, as shown in Figures 2 to 5 and identified by the reference symbol 16, are fed to the soldering system 10 through the inlet 12. Via a transport system, which is identified by the reference symbol 18 in Figures 2, 4 and 5, the printed circuit boards 16 are transported in the transport direction 20 along an x-axis through the soldering system 10 to the outlet 14. The transport system 18 can have two rails running parallel to one another, in which transport chains, belts or rollers, on which the printed circuit boards 16 rest or which carry the respective printed circuit board 16, are provided.

[0035] The soldering system 10 comprises various modules, although mixed modules with mixed processing functions are also possible. Downstream of the inlet 12 is a flux module 22, in which the areas of the circuit board 16 that are exposed to liquid solder during the soldering process are wetted with flux. Downstream of the flux module 22 is a heating module 24, in which the circuit boards 16 are preheated. Downstream of the heating module 24 are two soldering modules 26 and 28, in which circuit boards can be soldered independently of one another. For this purpose, independently movable solder pots (not shown) are arranged in the soldering modules 26 and 28, each of which generates a soldering wave. During the soldering process, the solder pot or the soldering wave is moved to the location on the circuit board 16 where the component is ultimately to be soldered. After the soldering process, the soldered circuit board is fed to the output 14, whereby the output can also be the input.

[0036] Figures 2 and 3 show a simplified representation of the heating module 24 and its key components. First, the transport system 18 extending through the soldering system 10 can be seen, with which the printed circuit boards 16 can be transported along the transport direction 20 in a transport plane E into and out of the heating module 24.

[0037] As is clear from Figure 3, electrical or electronic components 25 are provided on the top side of the circuit board 16 and are to be soldered in the soldering system 10. The components 25 have feet that extend through the circuit board 16 and are soldered to the circuit board 16 from below in the soldering module 28 (through-hole technology). Electrical or electronic components 27 can also be provided on the underside of the circuit board which are not soldered in the soldering system 10, but are already attached or pre-assembled on the circuit board 16 in some other way before the circuit board 16 is transported to the soldering system 10, for example by means of pressing or by means of another soldering process.

[0038] The heating module 24 comprises a module inlet 30 and a module outlet 32, wherein the module inlet and the module outlet can also be identical or at the same location. The circuit board 16 can be moved via the module inlet 30 into the heating module 24 and there into a heating position, as shown in Figure 2, in which the actual heating process takes place. Once the preheating of the circuit board 16 is completed, the circuit board 16 can be transported from the heating position shown in Figures 2 and 3 through the module outlet 32 ​​along the transport direction 20 out of the heating module 24 into the adjoining soldering module 26, 28. A reversal of the transport direction or a different transport direction is also conceivable.

[0039] 2 and 3, the heating module 34 has a base 34 in or on which heat radiators 36 are provided, which may be tubular. In the exemplary embodiment shown in Figures 2 and 3, the heat radiators run transversely to the transport direction 20, in the direction of a y-axis. It is also conceivable for the radiators to be positioned parallel to or differently from the transport direction. During operation, the heat radiators 36 radiate, in particular, infrared radiation towards the circuit board 16, so that the latter is heated by means of the radiation. In order to heat the circuit board not only superficially, it is advantageous to introduce heat energy into the circuit board by means of infrared radiators.

[0040] In the embodiment of Figures 2 and 3, the heat radiators 36 are located below the printed circuit board 16 in order to preheat it from below. This is useful because the components 25 are soldered using a soldering wave from below the printed circuit board 16. However, it is also conceivable to provide further

[0041] Heat radiators 36 are provided to heat the circuit board 16 from above as well. In this case, it makes sense to provide additional reflector bulkheads 56, 58 above the circuit board 16, as shown in Figure 4 and described below, or bulkheads that cover the entire inlet and outlet area in height, if possible.

[0042] As is further clear from Figures 2 and 3, a reflector bulkhead 40 and 52 is provided at the module inlet 30 and at the module outlet 32, respectively, which reflector bulkhead can be adjusted along a z-axis running transversely to the x-axis and y-axis into an operating position shown in Figure 3, in which the circuit board 16 is in the heating position. As is further clear from Figure 3, a distance Di exists in the operating position between the transport plane E and the reflector bulkhead 40 or its upper edge 42. In an open position of the reflector bulkhead 40, in which the reflector bulkhead 40 completely exposes the module inlet 30, the distance between the transport plane E and the reflector bulkhead 40 or a wall 44 delimiting the module inlet 30 at the bottom is the value D2, where D2 is greater than Di. The value D2 corresponds to the maximum throughput height specified by the machine, with D2 preferably being in the range of 60 mm to 100 mm, or greater.This ensures that printed circuit boards 16 with components 27 that have a comparatively large installation height can be soldered.

[0043] The distance Di can be set so that a reduced throughput height is achieved which is only slightly greater than the maximum (here downward) installation height H of the circuit board 16 or of the components 27 thereon. This ensures that the circuit board 16 can be transported collision-free through the module inlet 30 with the reflector bulkhead 40 in the operating position into the heating module 24. If several identically equipped circuit boards 16 are transported one after the other into the heating module 24, the reflector bulkhead 40 remains in its operating position. Only when a printed circuit board 16 with components whose installation height H exceeds the distance Di is to be introduced into the heating module, the reflector bulkhead 40 is lowered so far that a collision-free transport of the printed circuit board 16 together with components into the heating module 24 is possible.

[0044] To adjust the reflector bulkhead 40, drives 48 in the form of electric motors or pneumatic motors / cylinders are provided, which can be controlled via a controller 50. The controller 50 can be set up such that, depending on the installation height of the circuit board 16, it adjusts the reflector bulkhead 40 into the operating position so that the circuit board with the components 27 arranged thereon can be transported into the heating module 24 without collision, but preferably with a small distance to the reflector bulkhead 40 or to its upper edge 42. If, therefore, comparatively flat components 27 are provided on the circuit board 16, a low passage height Di can be set; if comparatively tall components 27 are provided on the circuit board 16, the adjustment of the reflector bulkhead can be such that a greater required passage height Di results.The drives 48 can also be manually operated drives, for example by means of a crank. Furthermore, it is conceivable that the adjustment of the reflector bulkheads 40, 52 can also take place without drives. For example, it is conceivable that elongated holes extending in the z-direction are provided on the reflector bulkheads, through which fastening screws extend, which are fastened to suitable components on the heating module 24. By loosening the screws, the respective reflector bulkhead 40, 52 can be adjusted. Once it has reached the required or predetermined height, the screws can be tightened.

[0045] As is clear from Figures 2 and 3, not only is a reflector bulkhead 40 provided at the module inlet 30, but also another, corresponding reflector bulkhead 52 at the module outlet 32. The reflector bulkhead 52 is adjustable in the z-direction in accordance with the reflector bulkhead 40. For this purpose, corresponding drives (not shown in the figures) are preferably provided for the drives 48 at the module inlet, which are controlled accordingly by the controller 50.

[0046] Figure 3 shows how the heat radiators 36 also radiate heat in the direction of the module inlet 30 or module outlet 32. The heat radiation is indicated by the arrows 54. Because the reflector bulkhead 40 or 52 is in its operating position, the radiation 54 directed towards the module inlet 30 or module outlet 32 ​​is reflected at the reflector bulkhead 40, 52 towards the printed circuit board 16 or the inner region of the heating module. Heat radiation which, without the reflector bulkheads 40, 52, would emerge from the heating module 24 through the opening with the passage height D2, is held in the heating module 24 due to the reflection 40, 52 at the respective reflector bulkhead 40, 52 and thus contributes to the uniform heating of the printed circuit board 16. The circuit board 16 can be heated sufficiently well, particularly in its edge regions 53, due to the reflection of the heat radiation 54 by the reflector bulkhead 40, 52.Furthermore, the provision of reflector bulkheads 40, 52 ensures that less heat radiation escapes the heating module 24. This prevents unwanted heating of components located outside the heating module 24. Furthermore, the soldering system 10 or the heating module 24 can be operated more energy-efficiently.

[0047] Figure 4 shows a heating element 124 with top and bottom heating, in which components corresponding to the heating element 24 according to Figures 2 and 3 are provided with corresponding reference numerals. While in the embodiment according to Figures 2 and 3 the reflector bulkheads 40, 52 are each provided only below the transport plane E or the respective circuit board 16, the heating module 124 also has upper reflector bulkheads 56 and 58. A reflector bulkhead 56, 58 provided above the transport plane E is particularly advantageous when heat radiators are provided not only on the base 34, but also in or on the cover element 38 above the circuit board 16. The reflector bulkheads 56, 58 provided above the transport plane ensure that heat radiation from the heat radiators provided above the transport plane remains in the respective heating module.In addition, heated air is better enclosed in the heating area, which is beneficial for heat transfer. The arrangement is such that the reflector bulkheads 40, 56 can be moved toward and away from each other in the z-direction. Correspondingly, the reflector bulkheads 42, 58 can also be moved toward and away from each other in the z-direction.

[0048] In the heating module 124 shown in Figure 4, the bulkheads are set to the smallest distance so that the products can still enter the heater. Alternatively, to transport the respective circuit board 16 into the heating module 124, the two reflector bulkheads 40, 56 are adjusted to an open position. After the circuit board 16 has reached its heating position, the two reflector bulkheads 40, 56 are moved toward each other so that the module entrance 30 is at least largely closed.

[0049] The two reflector bulkheads 40, 56 have open-edged recesses 60 which are arranged such that when the module entrance is closed, i.e. when the two reflector bulkheads 40, 56 reach their operating position, the transport means 18 are located within the recesses 60.

[0050] This has the advantage that, despite the provision of the transport means 18, the module entrance 30 can be largely closed. Additional cutouts, for example, due to special product geometries, are also possible.

[0051] Corresponding to the reflector bulkheads 40, 56, the reflector bulkheads 52, 58 at the module outlet 32 ​​can also have such recesses 60. This has the advantage that not only the module inlet 30, but also the module outlet 32 ​​can be at least largely closed in the operating position of the reflector bulkheads 52, 58. The heating module 124 can, corresponding to the heating module 24, have drives 48 and a controller 50 (not shown in Figure 4) which is configured to move the reflector bulkheads 40, 56 into an open position during the transport of the respective circuit board 16 into the heating module 24 and, after the respective circuit board 16 has reached its heating position, to move the reflector bulkheads 40, 56 into the operating position closing the module inlet 30.Accordingly, drives can drive the reflector bulkheads 52, 58 at the module output in such a way that they move from their closed operating position into an open position when the respective printed circuit board 16 is moved from the heating module 24 into the adjoining soldering module 26.

[0052] Figure 5 shows a further embodiment of a heating module 224, wherein corresponding components in the heating module 124 are provided with corresponding reference numerals. The heating module 224 differs from the heating module 124 in that reflector bulkheads 62, 64 are provided which are not arranged to be adjustable toward and away from one another in the vertical z-direction, but rather in the y-direction. In the open position of the reflector bulkheads 62, 64 shown in Figure 5, the circuit board 16 can be transported along the transport direction 20 into the heating module 224. After it has reached the heating position, the reflector bulkheads 62 and 64 are moved toward one another, whereby the module inlet 30 is at least largely completely closed. During the heating of the circuit board 16, no noticeable heat radiation escapes from the heating module 224.Even if reflector bulkheads 62, 64 are shown only at the module inlet in Figure 5, it is conceivable within the scope of the invention to also provide corresponding reflector bulkheads at the module outlet 32.

Claims

Patent claims 1. Selective soldering system heating module (24, 124, 224) for preheating printed circuit boards (16) populated with components (25, 27), with a base (34), with a module inlet (30) and a module outlet (32), wherein during operation the respective printed circuit boards (16) are transported along a transport direction (20) from the module inlet (30) into a heating position and from the heating position to the module outlet (32), and with heat radiators (36) arranged in or on the base (34), characterized in that at the module inlet (30) and / or at the module outlet (32) at least one reflector bulkhead (40, 52, 56, 58, 62, 64) is provided, wherein the at least one reflector bulkhead (40, 52, 56, 58, 62, 64) is designed such thatthat in the operating position it reflects the radiation emitted by the heat radiators (36) in such a way that it remains in the heating module (24, 124) and contributes to the preheating of the respective printed circuit board (16).

2. Heating module (24, 124) according to claim 1, wherein the at least one reflector bulkhead (40, 52, 56, 58) is adjustable in a z-direction perpendicular to the floor.

3. Heating module (224) according to claim 1 or 2, wherein the at least one reflector bulkhead (62, 64) is arranged in a adjustable in the y-direction parallel to the ground.

4. Heating module (24, 124, 224) according to claim 1, 2 or 3, wherein the at least one reflector bulkhead (40, 52, 56, 58, 62, 64) has open-edged recesses (60) for transport means (18) running in the transport direction, so that in the operating position the transport means (18) are in the recesses (60) and the module inlet (30) and / or the module outlet (32) is at least largely closed.

5. Heating module (24, 124, 224) according to one of the preceding claims, wherein at least two reflector bulkheads (56, 58, 62, 64) are provided at the module inlet (30) and / or at the module outlet (32), which reflector bulkheads can be adjusted towards and away from each other.

6. Heating module (24, 124, 224) according to one of the preceding claims, wherein at least one drive (48) is provided for adjusting the at least one reflector bulkhead (40, 52, 56, 58, 62, 64).

7. Heating module (24, 124, 224) according to claim 6, wherein a control (50) controlling the drive (48) is provided, which is configured such that the at least one reflector bulkhead (40, 52, 56, 58, 62, 64) is adjusted to the operating position depending on a construction height (H) of the respective circuit board (16).

8. Heating module (24, 124, 224) according to claim 7, wherein the control (50) is further configured such that the adjustment is such that in a first operating position the distance (Di) between the at least Reflector bulkhead (40, 52, 56, 58) and transport plane (E) is equal to or slightly greater than the installation height (H) of the respective circuit board (16).

9. Heating module (24, 124, 224) according to claim 7 or 8, wherein the controller (50) is further configured such that the adjustment is such that after the respective circuit board (16) reaches the heating position, the at least one reflector bulkhead (40, 52, 56, 58, 62, 64) is adjusted to a second operating position in which the module inlet (30) and / or the module outlet (32) is at least largely closed.

10. Selective soldering system (10) for soldering components present on a printed circuit board (16), comprising a flux module (22), a soldering module (28) and a heating module (24, 124, 224) according to one of the preceding claims, provided between the flux module (22) and the soldering module (28).

11. A method for operating a selective soldering system (10), wherein the selective soldering system (10) comprises a heating module (24, 124, 224) and heat radiators (36) arranged in the heating module (24, 124, 224), characterized in that when a printed circuit board (16) is in a heating position in the heating module (24, 124, 224), the heating module (24, 124, 224) is at least slightly closed in an operating position with an adjustable reflector bulkhead (40, 52, 56, 58, 62, 64) so ​​that in the operating position it reflects the radiation emitted by the heat radiators (36) in such a way that it remains in the heating module (24, 124) and contributes to the preheating of the respective printed circuit board (16).

12. The method according to claim 11, wherein the at least one reflector bulkhead (40, 52, 56, 58, 62, 64) is adjusted to the operating position depending on a construction height (H) of the respective circuit board (16).

13. The method according to claim 12, wherein in a first In the operating position, the distance (Di) between the at least one reflector bulkhead (40, 52, 56, 58) and the transport plane (E) is equal to or slightly greater than the installation height (H) of the respective circuit board (16), and wherein the adjustment is further such that, after the respective circuit board (16) reaches the heating position, the at least one reflector bulkhead (40, 52, 56, 58, 62, 64) is adjusted to a second operating position in which the module inlet (30) and / or the module outlet (32) is at least largely closed.

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