DE112009002278T5 - Reflow soldering device with a process chamber having a partition wall Method for fill-soldering using such a reflow soldering device - Google Patents

Abstract

Reflow soldering device comprising
A process chamber having a conveyor for conveying assemblies to be subjected to a heat treatment,
Blower means (28) for supplying an air flow to the printed circuit boards,
Heating means (35) for heating the air flow,
characterized,
in that a separating wall (10) is arranged in the process chamber, which subdivides the process chamber in the transverse direction into two process chambers (11, 12), wherein the blower devices (28) and heaters (35) of the two process chambers (11, 12) are independently controllable , so that different temperatures can be set in the process sub-chambers (11, 12).

Description

The present invention relates to a reflow soldering apparatus and a reflow soldering method.

From the EP 1 525 067 B1 is a process chamber for a reflow soldering known. In this process chamber, a conveyor for conveying assemblies is provided. The assemblies are printed circuit boards with electronic components, wherein the electronic components are soldered to the circuit board. For this purpose, a heated air flow is generated by means of fan rollers, which is supplied to the modules. Above and below the conveyor track of the assemblies, two sets of fan rollers are arranged. The fan rollers extend over the entire width of the conveyor track, whereby a homogeneous, band-shaped air flow is achieved. As a result, a uniform over the entire width of the conveyor track temperature distribution is achieved, which is very precisely adjustable.

This known reflow soldering apparatus has proven very successful in practice, since it can reliably and very accurately predetermined temperature profiles are applied to the modules with her.

From the DE 100 31 071 C2 is a plant for the thermal treatment of workpieces, in particular for soldering, in which in each process or heating level in each case at least two transport devices are arranged side by side. The transport devices can be designed in the manner of a chain conveyor and arranged side by side.

From the EP 1 116 147 A1 shows a further device for heating printed circuit boards, in which in a horizontal transport plane two heating streets are arranged side by side and parallel to each other. It is also possible to arrange several heating streets above each other.

The DE 102 26 593 A1 is your patent application, which relates to a reflow device with a fan roller, which is open at its two end faces, wherein the fan roller is arranged with its axis of rotation transverse to the transport direction of the printed circuit boards to be soldered. The air is drawn in via the end faces of the fan roller and discharged radially from the roller to the printed circuit boards to be soldered.

In the US 36,941 E a furnace is described for cooking, which has two conveyors and a circulating air blower to apply hot air to the object to be heated.

The invention has the object of providing such a reflow soldering device and a method for reflow soldering educate so that a temperature profile can be generated with essentially the same quality and reliability, with a more cost effective design of the reflow soldering a higher throughput of processing assemblies to be achieved.

The object is achieved by a reflow soldering device having the features of claim 1 and by a method having the features of claim 12. Advantageous embodiments are specified in the respective subclaims.

• – eine Prozesskammer mit einer Fördereinrichtung zum Befördern von einer Wärmebehandlung zu unterziehenden Leiterplatten,
• – einer Gebläseeinrichtung zum Zuführen eines Luftstroms zu den Leiterplatten,
• – einer Heizeinrichtung zum Erwärmen des Luftstroms.

The reflow soldering device comprises

• A process chamber having a conveyor for conveying printed circuit boards to be heat treated,
• A blower device for supplying an air flow to the printed circuit boards,
• - A heater for heating the air flow.

The reflow soldering device according to the invention is characterized in that a partition wall is arranged in the process chamber, which subdivides the process chamber in the transverse direction into two process sub-chambers, whereby blower devices and heating devices are provided in each process sub-chamber. The blower devices and heating devices of the two process subchambers can be controlled independently of one another by means of a control device, so that different temperatures can be set in the process subchambers.

In the two process sub-chambers thus different products or different modules can be processed with different temperature profiles. By integrating two process chambers with a different temperature profile in a reflow soldering a twice as high throughput is achieved as with a conventional reflow soldering. By providing two process subchambers, it is not necessary that all components of the soldering device be duplicated. Thus, the two process sub-chambers are arranged in a common housing. The control device for controlling the individual components of the soldering device comprises a hardware module (processor unit, keyboard, screen, etc.), which substantially corresponds to the hardware module of the reflow soldering device mentioned above. Only the control software used for independent control of the two process sub-chambers is formed.

Preferably, in each case a conveyor is arranged in the Prozessteilkammern, which are controlled differently, so that the temperature profiles can be traversed at different speeds.

The reflow soldering device has a housing in which the two process sub-chambers are formed, and it is preferably a single electrical control unit for driving both Prozessteilkammern provided.

The reflow soldering device is preferably formed with a single cooling device for cooling the printed circuit boards in both Prozessteilkammern.

The reflow soldering device has as fan devices preferably radial fans, which are arranged laterally from a conveyor track for the printed circuit boards.

By using a centrifugal fan arranged laterally of the conveyor track, a centrifugal fan replaces two fan rollers of the reflow soldering device explained in the introduction. This allows despite the provision of two process chambers, the number of fans or blowers compared to the above-mentioned reflow soldering device to keep approximately constant.

The partition between the two isolation sub-chambers is preferably provided with a thermal insulation layer.

• – Geringere Stellfläche
• – Weniger Bedarf an Medien (Strom, Stickstoff, etc.)
• – Geringerer Verschleiß
• – Verminderter Wartungsaufwand
• – Höhere Flexibilität
• – Geringere Personalkosten
• – Höhere Wirtschaftlichkeit

The advantages achieved with the reflow soldering device according to the invention over two conventional soldering devices, with which the same throughput is achieved, are:

• - Lower footprint
• - Less need for media (electricity, nitrogen, etc.)
• - Less wear
• - Reduced maintenance
• - Higher flexibility
• - Lower staff costs
• - Higher economic efficiency

The invention is explained below by way of example with reference to an embodiment shown in the drawings. The drawings show:

1 a reflow soldering device according to the invention with opened lid in a perspective view,

2 the soldering device after 1 in cross section,

3 the cross-sectional view after 2 in a schematically simplified representation, wherein in one half of the soldering device, the flow directions of the air flow are shown, and

4 one half of the soldering device with a section in the longitudinal direction and in the transverse direction schematically simplified, the flow directions are shown by arrows.

The reflow soldering device according to the invention 1 has a housing 2 on top of that, from a lower shell 3 and a lid pivotally mounted on the housing pan 4 consists. The housing pan has two end walls 5 , two side walls 6 and a bottom wall 7 on. In the end walls 5 are horizontal slots 5a formed by which electronic assemblies can be added or removed. Between the slots 5a are conveyors (not shown) for transporting the assemblies 8th intended. These conveyors are conventionally formed by, for example, narrow conveyor belts on which the assemblies are placed. The conveying speed is individually adjustable. The modules are in the conveying direction 9 transported along a conveyor track through the housing. The horizontal plane in which the conveyor track lies forms a plane of symmetry for the essential components of the reflow soldering device 1 ,

According to the invention, the housing 2 by a longitudinal partition wall 10 divided so that two process sub-chambers 11 . 12 are formed. The process chambers 11 . 12 are symmetrical to the partition 10 arranged and substantially symmetrical to the partition wall 10 educated.

The partition 10 is formed in the present embodiment of a metal sheet. In the context of the invention, it can also be unilaterally or bilaterally with an insulating layer for thermal insulation of the two process sub-chambers 11 . 12 be provided. It can also be formed of a different material than metal.

Above and below the conveyor tracks are baffles 13 educated. The air ducts 13 have a base wall 14 on, which is rectangular in plan view and arranged parallel to the plane of the conveyor track. The base wall 14 is at its edge with a peripheral peripheral wall 15 provided, extending from the base wall 14 extending away from the plane of the conveyor track.

In the base wall 14 are nozzle slots 16 educated. The nozzle slots 16 can have a beaded in the direction of the conveyor track edge. The nozzle slots 16 are in the present embodiment, transverse to the conveying direction 9 running trained.

In the transverse direction to the conveying direction 9 run return pipes 17 extending between two opposite sides of the perimeter wall 15 extend and at this each with an opening 18 lead. In 4 are the peripheral walls 15 at the height of the openings 18 shown with a dashed line.

To the partition 10 opposite side of the airway corner 13 is a longitudinally extending vacuum or suction channel 20 educated. This vacuum channel 20 is from a lower and upper vacuum duct baffle 21 bounded with an edge to the edges of the partition 10 removed portion of the peripheral wall 15 of the airship corner 14 is set, from there vertically away from the vanes 13 extends into a bow 22 passes over and on the other side of the arch in a vertical outer boundary wall 25 passes, which extends to about the height of the conveyor track. From there, the vacuum duct baffle 21 again a piece towards the partition 10 for the formation of a bottom wall 23 guided. From the bottom wall 23 extends a vertical inner boundary wall 24 to which the of the partition 10 distant side of the air duct 13 borders. In the neighboring area to the base wall 14 of the baffle 13 are at the inner boundary wall openings 19 formed so that the area between the conveyor track and the base wall 14 communicating with the vacuum channel 20 connected is. The vacuum channel 20 is still with the return pipes 17 but the openings 18 in the peripheral wall 15 communicatively connected.

At the outer boundary walls 25 have the vacuum channels 20 each a semicircular opening 26 on, wherein each one above and below the conveyor track arranged vacuum channel 2 herself with her semicircular opening 26 complement so that they form a circular opening.

The outer boundary wall 25 of the vacuum channel 20 is a distance from the adjacent side wall 6 of the housing 2 the reflow soldering device 1 arranged. The bows 22 the vacuum channels 20 are a distance from the bottom wall 7 or to the lid 4 of the housing 2 arranged. The intermediate area between the vacuum duct baffle 21 and the baffle 13 on one side and the side wall 5 , the bottom wall 7 and the lid 4 of the housing 2 on the other hand limit an overpressure channel 27 , In this overpressure channel 27 is a radial fan 28 arranged. The radial fan 28 has a radial rotor 29 on, the one rotor disk 30 and with at the periphery of the rotor disk 30 radially oriented rotor blades 31 is trained. The rotor blades 31 form a rotor rim whose inside diameter is about the diameter of the through the semicircular openings 26 corresponds to limited opening, wherein the rotor ring is arranged in alignment with this opening. The rotor disk 30 has a hub in the middle 32 on, on one through the side wall 6 of the housing 2 guided wave 33 sitting. The wave 33 will be outside the case 2 from a motor 34 driven.

The radial rotor 29 is configured such that in operation, when the rotor is rotated, air from the center of the radial rotor 29 through the rotor blades 31 radially outward into the overpressure channel 27 is accelerated. The radial rotor 29 is from a radial radiator 35 Surrounded by the radial fan 28 warmed to the outside air heated.

In the longitudinal direction of the housing 2 the reflow soldering device 1 are several heating segments 36 each formed a radial fan 28 with a radial radiator 35 , an upper and a lower vacuum channel 20 and an upper and lower spoiler 13 exhibit. The heating segments 36 are separated from each other by transverse to the conveying direction 9 running segment partition walls 37 separated from each other ( 4 ). This makes it possible in the individual heating segments 36 to set different temperatures, as the individual centrifugal fans 28 and radiators 35 by means of a control device (not shown) are independently controllable.

The of the centrifugal fans 28 in the overpressure channel 27 Promoted air is first from the radial radiator 35 heated. The heated air flows along the arches 22 to the baffles 13 , The air from the overpressure channel 27 happens the nozzle slots 16 The heated air emerges from the nozzle slots 16 from and meets the transported along the conveyor assembly 8th , The assemblies 8th are heated by the heated air to a predetermined temperature. The conveyor is supplied with heated air both from below and from above. The air streams turn in the region of the conveyor track to the base wall 14 diverted. The base wall 14 and those from the nozzle slots 16 leaking air pushes the air reflected from the assemblies aside, ie transverse to the conveying direction 9 from. As a result, the air flow is transverse to the conveying direction 9 partly towards the partition 10 and the other part towards the vacuum channel 20 derived The part of the air flow derived from the vacuum channel flows directly through the openings 19 in the vacuum channel 20 ( 4 ). The other part flows towards the partition 10 , in the area between the partition 10 and the peripheral wall 15 of the baffle 13 and from there through the return pipes 17 in the vacuum channel 20 ,

In the vacuum channel 20 is the used or cooled air collected and through the openings 26 the centrifugal fan 28 fed again. The air is thus circulated in the individual heating segments in the circuit. The circulation speed can be determined by the rotational speed of the centrifugal fan 28 be set. The heat supplied can be to the radiators 35 be set individually.

Furthermore, in the process sub-chambers 11 . 12 the conveying speed can be set independently. Thus, completely independent temperature profiles can be generated in the two process chambers.

When using a metal plate as a partition 10 can be in adjacent sections of the two process sub-chambers 11 . 12 Set temperature differences of approx. 40 ° C. If the partition provided with a thermal insulation layer, so much higher temperature differences can be set, the z. B. 80 ° C or more.

The reflow soldering device has at its in the direction of conveyance 9 rear end region a cooling device (not shown) to the assemblies 8th cool. It is a single cooling device for both Prozessteilkammern 11 . 12 intended. In the context of the invention can also be two cooling devices for each one of the two process sub-chambers 11 . 12 be provided.

Below are two groups of applications, each requiring a different soldering profile. These different soldering profiles can be performed simultaneously in the reflow soldering device according to the invention. The conveyor paths in the two process chambers 11 . 12 are referred to as track 1 and track 2, respectively:

Trace1:

• – Thermisch sensitive Baugruppen
• – Dünne Leiterplatten
• – Einfache Cu-Lagen
• – Geringe Bestückdichte mit homogener Struktur Wenig massereiche Bauteile
• – Thermisch gering anspruchsvoll
• – Bleihaltige Legierung (SN63 Pb37; Schmelzpunkt 183°C)
• – Delta-Temp. >/= 0

Soldering profile with low peak temperature of approx. 200 ° C-220 ° C → peak, for simple assemblies

• - Thermally sensitive assemblies
• - Thin circuit boards
• - Simple Cu layers
• - Low assembly density with homogeneous structure Low-mass components
• - Thermally low demanding
• - Leaded alloy (SN63 Pb37, melting point 183 ° C)
• - delta temp. > / = 0

TRACK 2:

• – Thermisch anspruchsvolle Baugruppen
• – Dicke Leiterplatten
• – Starke Cu-Lagen
• – Dichte Bestückung mit inhomogener Struktur.
• – Viele Massereiche und Großflächige Bauteile
• – Thermisch sehr anspruchsvoll
• – Bleifreie Legierung (SnAg3, 8Cu0,7; Schmelzpunkt 217°C)
• – Delta-Temp. > 0

Soldering profile with increased peak temperature of approx. 290 ° C-300 ° C → peak, for complex assemblies.

• - Thermally demanding assemblies
• - Thick printed circuit boards
• - Strong Cu layers
• - Dense assembly with inhomogeneous structure.
• - Many high-mass and large-area components
• - Thermally very demanding
• - Lead-free alloy (SnAg3, 8Cu0.7, melting point 217 ° C)
• - delta temp. > 0

The reflow soldering device according to the invention is also suitable for automatically carrying out an adhesive bonding process. Here, in parallel, two different adhesive profiles can be driven.

With the soldering device according to the invention, a very wide variety of thermal processes can be carried out, with fundamentally other products than printed circuit boards also being able to be processed herewith. However, the reflow soldering device according to the invention is designed primarily for the processing of printed circuit boards or printed circuit boards containing assemblies.

The invention has been explained above with reference to an embodiment in which a baffle is used. Within the scope of the invention, instead of an air-guiding basin, another suitable air-guiding device may also be provided, as long as it controls the airflow from the overpressure channel 27 to the modules 8th and from there the derivative to the vacuum channel 20 allowed. Preferably, the recirculated air flow is divided and a part by means of the return tubes 17 headed back. In the context of the invention, it is also possible to form the nozzles for supplying the heated air to the modules directly to the return tubes by, for example. The side walls are slightly extended in the direction of the conveyor track in each case by a projection. These projections then limit the nozzles.

LIST OF REFERENCE NUMBERS

1

Reflow soldering

2

casing

3

housing trough

4

cover

5

end wall

5a

slot

6

sidewall

7

bottom wall

8th

module

9

conveying direction

10

partition wall

11

Process sub-chamber

12

Process sub-chamber

13

Luftleitbecken,

14

base wall

15

peripheral

16

nozzle slot

17

return pipe

18

opening

19

opening

20

Vacuum or suction channel

21

Unterdruckkanalleitblech

22

bow

23

bottom wall

24

inner boundary wall

25

outer boundary wall

26

semicircular opening

27

Overpressure channel

28

centrifugal fan

29

radial rotor

30

rotor

31

rotor blades

32

hub

33

wave

34

engine

35

radial radiators

36

heating segment

37

segment partition

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1525067 B1 [0002]
• DE 10031071 C2 [0004]
• EP 1116147 A1 [0005]
• DE 10226593 A1 [0006]
• US 36941 E [0007]

Claims (13)

Reflow soldering apparatus comprising - a process chamber with a conveying device for conveying components to be subjected to a heat treatment, - blower devices ( 28 ) for supplying an air flow to the printed circuit boards, heaters ( 35 ) for heating the air stream, characterized in that in the process chamber a partition wall ( 10 ) is arranged, which the process chamber in the transverse direction in two process sub-chambers ( 11 . 12 ), wherein the blower devices ( 28 ) and heaters ( 35 ) of the two process sub-chambers ( 11 . 12 ) are independently controllable, so that in the process sub-chambers ( 11 . 12 ) different temperatures are adjustable. Reflow soldering apparatus according to claim 1, characterized in that in the process sub-chambers ( 11 . 12 ) in each case a conveyor is arranged, which can be controlled differently. Reflow soldering device according to claim 1 or 2, characterized in that the reflow soldering device comprises a housing ( 2 ), in which the two process sub-chambers ( 11 . 12 ) are formed, and an electrical control unit for controlling in the two process sub-chambers ( 11 . 12 ) contained components. Reflow soldering apparatus according to one of claims 1 to 3, characterized in that a single cooling device for cooling the assemblies in both process sub-chambers ( 11 . 12 ) is provided. Reflow soldering device according to one of claims 1 to 4, characterized in that the blower devices ( 28 ) each at least one radial rotor ( 29 ) laterally from a conveyor track for the assemblies ( 8th ) is arranged. Reflow soldering device according to claim 5, characterized in that the radial rotor ( 29 ) at the peripheral region has a blade ring, which is designed such that air from the center of the radial rotor ( 29 ) is blown radially outward. Reflow soldering apparatus according to claim 5 or 6, characterized in that adjacent to the conveyor track of the assemblies ( 8th ) transverse to the conveying direction ( 9 ) extending nozzle slots ( 16 ) provided in a base wall ( 14 ) are formed. Reflow soldering apparatus according to claim 7, characterized in that with respect to the conveying path of the base wall ( 14 ) opposite side return tubes ( 17 ), which extend from the region adjacent to the dividing wall (FIG. 10 ) over the base wall ( 14 ) to allow air from the dividing wall to the blower device (FIG. 28 ). Reflow soldering device according to one of claims 1 to 8, characterized in that the partition wall ( 10 ) is provided with a thermal insulation layer. Reflow soldering device according to one of claims 1 to 9, characterized in that a control unit is provided, which is designed to control a soldering process. Reflow soldering device according to one of claims 1 to 10, characterized in that a control unit is provided, which is designed to control a bonding process. Method for reflow soldering assemblies, in which a reflow soldering apparatus, in particular according to one of claims 1 to 11, comprising - a process chamber with a conveying device for conveying components to be subjected to a heat treatment, - blower devices ( 28 ) for supplying an air flow to the printed circuit boards, heaters ( 35 ) for heating the air stream, wherein in the process chamber a partition wall ( 10 ) is arranged, which the process chamber in the transverse direction in two process sub-chambers ( 11 . 12 ), wherein the blower devices ( 28 ) and heaters ( 35 ) of the two process sub-chambers ( 11 . 12 ) are independently controllable, so that in the process sub-chambers ( 11 . 12 ) different temperatures are used, and assemblies simultaneously with different temperature profiles in the process sub-chambers ( 11 . 12 ) are soldered. A method according to claim 12, characterized in that the assemblies in the process sub-chambers ( 11 . 12 ) are each conveyed by means of a separate Födereinrichtung at different speeds.

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