JPS60257970A - Soldering device and method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to an apparatus and method for soldering, and more particularly, the present invention relates to an apparatus and method for soldering, and more particularly, to heating an article in a vapor phase and separately applying solder to the heated article. Relates to coating equipment and methods.

1 US 1 branch and its heel point soldering are used for a large number of different items, especially items in the electronic field,
It is especially widely used in the production of printed circuit boards. Wave soldering equipment has been widely employed in the manufacture of printed circuit boards and similar articles. These devices include a reservoir of molten solder, into which the solder is pumped in waves and the circuit board is conveyed in contact with the waves so as to cover the desired area. The wave of solder is
It functions as a heat source for heating the circuit board and also functions as a solder source for applying solder to the board.

Wave soldering equipment is relatively complex and must be carefully designed and manufactured to form appropriately sized solder waves and provide the heating and solder application characteristics required for the particular article being processed. No. The wavelength of the waves must be sufficient to provide sufficient contact time to heat the surfaces to be soldered. Wave design is critical in relation to the article and the speed of the article in the wave. There is a maximum speed above which the article cannot be transported through a particular solder wave, but still provides sufficient heating. For higher speeds the wave shape would have to be reconfigured, which would also require a complete redesign of the system.

Solder wave height is also a critical factor and can be a limiting factor on the size of the article being processed. For example, on a printed circuit board where a component with leads is inserted, the length of the leads cannot be longer than the depth of the solder wave, otherwise the board will interfere with the long leads of the component. Therefore, it cannot be accommodated in a specific wave soldering device. Thus, when assembling components onto a circuit board, care must be taken to ensure that the length of the lead wires is smaller than the depth of the solder waves for the four-beam specific soldering equipment employed. No. Since the solder wave serves as both a solder source and a heating source, the dynamics of the system are complicated when the Abe solder equipment is designed for a specific purpose. These dynamics also make it difficult to change the characteristics of the solder wave to accommodate different types of articles.

Another type of soldering apparatus is a dowel-knob soldering apparatus that is provided with a solder reservoir for partially or completely dipping and immersing an article in order to apply solder to the article. Again, the molten solder acts as both a heat source and a solder applicator to heat the article to a soldering temperature.

U.S. Pat. No. 3, Reissue No. 3,999 shows a wave flow soldering apparatus in which a solder wave is formed at the bottom of a container containing heated saturated steam. The articles are conveyed through a vapor chamber, heated by immersion in the vapor phase, and soldered by passage through a solder wave. Although the solder is applied in an anaerobic atmosphere provided by a gas phase, locating the solder wave device within the chamber provides little improvement in the control or performance of the soldering operation. The criticality and relative complexity of the solder wave is exactly the same as above, and the presence of the solder wave in the heated steam does not change the critical design issues of the wave device.

Brazing & Soldering
An article entitled "The New Soldering Is a Method" by W. R. George (R. George) in August 1983 issue 5 of ``Soldering'' describes how articles were initially heated before being immersed in a molten solder bath. Drag soldering shows the device placed in an inert gas phase.

U.S. Pat. No. 3,825,164 discloses a soldering device having a tank containing a puddle of molten solder at the bottom and covered by a liquid fluxing bath, and a solder spraying device disposed within the flushing bath. indicates the device. The printed circuit board is subjected to a normal force c'=l'l'/'-ah in the fluxing bath for preheating.
sg a1. A, □, waka4. 6'1'5 Solder is sprayed onto one or both surfaces of the printed circuit board when it is removed.

The present invention is an apparatus for soldering circuit boards and other articles in which the articles are heated by an independently controlled gas phase system and the solder is controlled and controlled. The present invention provides an apparatus for applying solder by a separately controlled nozzle application system that acts to direct the applied flow toward the article. A container is provided for containing heated saturated inert vapor, and the article is introduced into the heated saturated inert vapor prior to application of the solder and is heated to a soldering temperature by the heated saturated inert vapor. Ru. One or more nozzles are provided within the container for directing one or more streams of molten solder onto a heated article, the impinging solder being retained by areas on the surface of the article. It will stick there.

In the case of a circuit board, solder is applied to the conductive paths of the circuit, through-holes that may be present in the circuit board, and to the leads or connection pads of components assembled or inserted onto the board. Ru.

Heating of the article is substantially effected by a heated gaseous atmosphere within the container, and the formation and control of this gaseous atmosphere is performed separately by a gaseous device. Solder application is accomplished by a dispensing nozzle that, in conjunction with an associated solder source and pump, independently forms the desired solder flow for a particular article. Thus, heating the article and applying solder to the article are separately controlled operations, and these operations are substantially independent of each other. Articles may be introduced into and removed from the processing vessel in any suitable manner appropriate for the particular application. Typically, for continuous manufacturing methods, articles are carried on a conveyor into a processing vessel for heating and soldering, and from the vessel by the conveyor.

Figure 1 shows a preferred embodiment of the soldering apparatus according to the invention, which is particularly suitable for soldering electronic circuit boards. The sealed container 10 defines therein a gas phase chamber 8 in which inert saturated steam heated to a predetermined temperature is heated to heat the article to be soldered. It is accommodated. At the bottom of the container 10,
A liquid 14 in the gas phase, typically Fluorinert F
A heater 12 is disposed within the chamber to heat the C-70 to a temperature sufficient to heat it to saturated steam. Cooling coils can be placed around the vessel wall at positions that define the upper limit of the vapor zone within the chamber. Objects such as circuit boards 27 enter the entrance throat 18
is carried into the chamber via the outlet throat 20, and is carried out from the chamber via the outlet throat 20.

These throats extend outwardly from opposite side walls of the container 10. A conveyor 22 for carrying circuit boards into and out of the gas phase chamber includes the inlet throat 18;
It extends through the interior chamber of the container 10 and the outlet throat 20 . The conveyor may be of any shape suitable to accommodate the particular articles being processed. For circuit boards, the conveyor may include a frame that holds the edges of the board with the board surface exposed for soldering. A pair of solder nozzles 24 and 26 are disposed within the chamber, each nozzle applying solder to opposite surfaces of a circuit board being conveyed past the nozzle along an article travel path within the chamber. It is placed in a position to apply the flow of water.

A solder pump 28, which supplies nozzles 24 and 26, is located within container 10 within a reservoir 30 containing melted solder. Reservoir 30 collects excess solder that runs off the board after the solder has been applied by the nozzle. Tame 3
0 also acts as a solder source for pump 28. Alternatively, a separate solder supply source may be provided.

Further, the solder pump may be placed outside the container.

The inlet and outlet throats are preferably shaped in relation to the container to minimize the escape of vapor from the container to the atmosphere. Such a shape is disclosed in commonly assigned U.S. Pat. No. 4,389,797! ,:rA,,
, 7 Ioyoua. . 7 Good. Although not limited to use with inlet and outlet throats such as This is because a large number of different types of goods can be provided. For continuous processing, it is preferable to provide a direct current or near direct current system for soldering, through which the items can be continuously transported through the soldering process.

The inlet throat 18 and the outlet throat 20 can be arranged in a more or less horizontal position, but in an upward or downward direction to provide the desired conveyance path and the essential reduction of vapor loss from their throats to the atmosphere. It can also be tilted.

The heating of the articles entering the chamber of the container and the application of solder to the heated articles are individually controllable and each substantially independent of the control of the other. Articles entering the chamber are heated by the gaseous atmosphere within the chamber. The formation and control of the gas phase atmosphere is performed by a gas phase device including a heater 12 and a gas phase liquid 14 and an associated heater control device. The solder application is carried out using application nozzles 24 and 26, which are configured to form the desired solder flow for the article which is heated to the desired temperature by the vapor phase device of the solder application prior to the solder application. and adjusted solder source 3 associated with the dispensing nozzle.
0 and pump 28. Solder leveling is accomplished by a solder leveling nozzle that is configured and adjusted to separately perform the desired leveling or removal function.

When processing only one side of the circuit board 27, the main soldering apparatus may be configured with only the lower nozzle 26 as shown in FIG. 2, or with the lower nozzle 24 as shown in FIG. It can be configured by

The apparatus of FIG. 1 is illustrated in representative configurations in FIGS. 4 and 5. A pair of conveyor chains 31 and 3
2 are separated from each other along the chain 3
4 is combined. These frames 34
0 for transport in 2 Acts to hold the printed circuit board. The frame 34 is each connected at its front end to the drive chains 31 and 32 by a coupling member 35 and includes side members or skids 36 that slide along a guide surface 38 within the container 10. The guiding surface within the container follows a downward path at the inlet of the container, indicated by the reference numeral 40, and then a uniform upward path through the container substantially co-linear with the outlet throat 20. .

A pair of idler wheels 42 and 44 are provided within the container for each chain 31 and 32 to vary the direction of chain movement as shown. Once the frame and the circuit board carried thereby are within the container, the frame and circuit board follow the path of the guide surface 38 and are shown in FIG. 4 for linear upward movement through the processing chamber. Take an upwardly sloping direction. By this means, the circuit board is conveyed in the desired direction for uniform movement past the solder nozzle, thereby minimizing the length of time that the circuit board is exposed to the high temperatures of the processing zone within the container. The desired relative position between the substrate surface and the opposing nozzle can then be maintained within the shortest convenient container length.

A pair of hold-down plates 64 are positioned on the conveyor to resiliently bias the lateral skids 36 of the conveyor frame into engagement with the grisso surface 38 and to hold the frame and the circuit boards housed thereby against the guide surface. has been done. The circuit board is thus maintained in a precisely guided position and orientation along its path past the solder nozzle.

Solder nozzles 24 and 26 are provided on opposite sides of the board being transported across a path of travel between them, each nozzle having an angular orientation of the nozzle orifice relative to the circuit board and a surface of the board opposite that of the nozzle. The offset, or spacing, from Typically, the nozzles are 45 mm on either side of an axis perpendicular to the substrate surface.
It is angularly adjustable over a range of degrees, and is also adjustable from the substrate surface. 4 minutes, )1 or
1.3 It is said that it can be adjusted within the range of 1 inch (0.64 to 2.54 cm). The lower nozzle 26 is also illustrated in FIG. 6 and has an elongated generally cylindrical shape with a linear orifice 52 extending along its length and a length sufficient to provide solder flow across the entire width of the circuit board. A cylindrical member 50 is provided.

Member 50 includes a lip 54 that is adjustable relative to lip 56 to form an adjustable orifice. The orifices are typically 10 to 30.
It has a gap in the mil range. The cylindrical member 50 is rotatable about its axis to select the desired angle of incidence of the solder stream applied to the opposing substrate surface with the precision of the orifice 52. This member 50 includes a linkage mechanism 58 for vertically adjusting the member 50 to select the spacing between the nozzle and the substrate surface facing it.
are combined. The upper nozzle 24 is similarly adjustable in its offset and angular direction from the opposing substrate surface. These nozzles are supplied with molten solder by a pump via piping 70 which is connected to a supply manifold 62 which is connected to a molten solder source 5 4 or reservoir.

Each solder nozzle is adjustable to select the angular position relative to the opposing substrate surface and to select the gap or spacing between the nozzle and the opposing substrate surface. The angular adjustability of each nozzle provides an angle of incidence for the impinging solder flow that can be perpendicular to the substrate surface or at an angle to the direction of substrate movement. The angular position of each nozzle and the spacing between the nozzle and the substrate surface are determined to provide the desired amount of solder and definition of the desired solder flow for the particular article being processed. The solder flow is individually controlled to provide the desired application of solder.

Since the article has been heated to the soldering temperature by the gas phase in the container before the solder is applied, the solder application nozzle need only be limited to applying the desired solder, and is not required to heat the article. There is no need to control it.

6 This device is effective for soldering various types of circuit boards.This device is effective for soldering various types of circuit boards. The device can also be used for so-called bare circuit boards, which have through-holes that connect circuit patterns to each other. It may also be employed for circuit board applications that accommodate leaded components having leads extending from the top or a mixture of leaded components and surface mount components. For this purpose, one or both solder nozzles can be employed.In some cases, solder needs to be applied to only one substrate surface;
The other solder nozzle can be rendered inactive by appropriately controlling the supply of solder to the nozzle.

The apparatus can also be employed for applying solder to one surface of a substrate by means of a nozzle, such that reflow soldering is performed on the opposite surface of the substrate. In some circuit boards, for example, after a solder paste is applied to the board, the board is heated to reflow the solder paste and form a bond between the associated component and the conductive areas on the board surface. Preferably, the components are attached to the substrate surface by soldering or flow soldering techniques. According to the device, reflow soldering can be carried out in a known manner by introducing the circuit board into heated saturated steam in a container. The opposite substrate surface can be soldered by a stream of solder from an associated nozzle. The device is therefore very flexible in providing the possibility of solder flow and reflow soldering all in a heated gas phase atmosphere within a single device.

The gas phase atmosphere within the container 10 is typically 415 to 4
It is heated to a temperature in the range of 50 degrees F (213 to 232 degrees C). The solder source is typically maintained in the same range. The solder in reservoir 30 is maintained in a molten state by the heated atmosphere within the container. '7 Alternatively, a separate IW heater can be installed in or around the reservoir to keep the half H1 at the desired temperature. Therefore, the gas phase atmosphere is 1. Before applying the semi-111 nozzle, the article is heated to a temperature of 1%, 1%.
The temperature is sufficient to reduce JK to l'-1 (J temperature).The half-rTI flow of each "i' In order to form the desired 7.!L curved shape in order to make the half-ITI suitable for (,1, melt +-, viscosity of half-111, Ij-elasticity 1.1 by pump 28). The article is determined in relation to the force and the size of the orifice of the nozzle.
It is pumped through the apparatus at a speed sufficient to heat the article and apply the appropriate amount of ζ to the heated article. In a typical configuration, if the circuit board moves through the container at a rate of 4 to 1 min.
It is transported at a speed of 0 feet (1.20 to 3.05 meters per minute).

On, the present invention ε3t ljl↓
Of course, it is not fixed.

4.1'2.1 i::i Explanation 9 8 Fig. 1 is a schematic side view of the IQ soldering device according to the present invention Fig. 2 is the device of Fig. 1 with the nozzle disposed below the article Schematic side view of a further embodiment of the apparatus of FIG. 1 in which a single nozzle is disposed on one side of the article, FIG. Figure 4 (1) is a schematic side view of the device in the desired configuration; Figure 5 (2) is a partially cutaway top view of the device of Figure 4; .: It is a perspective view with JJ missing.

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Claims (1)

[Scope of Claims] 1. Means (12) for generating heated saturated inert vapor in the chamber (10) at a temperature sufficient to heat the article (27) prior to solder application. ,14),
and means (22) for loading and unloading articles into and out of said gas phase chamber.
The heated article (27) is opposite to the passageway of the heated article (27) and directs the solder flow as the article is transported through the vapor phase chamber.
7) At least one element that acts to direct the
a continuous soldering device comprising: at least one nozzle (24, 26); and a solder source (30) coupled to the at least one nozzle (24, 26); a container (10) defining a phase chamber, means (12, 14), and means (22) for transporting the circuit board in said gas phase chamber. An apparatus for soldering a circuit board (27), comprising: solder m (30); and said solder source (30). at least one solder application nozzle (24, 26) coupled to and disposed within the vapor chamber for directing a flow of molten solder toward the heated circuit board (27); 3. A container (10) defining a gas phase chamber, heating the article (27) at a controlled temperature to saturation within the nayanha prior to solder application. Means for generating inert steam (12
, 14), in an apparatus for soldering an article (27), comprising: a source of molten solder (30); and a means for transporting the article (27) in said gas phase chamber; one or more nozzles (24, 26); A device characterized by comprising: 4. Device according to claim 3, characterized in that the solder source (30) is arranged in the gas phase chamber. 5. The container (10) comprises an inlet throat (18) and an outlet throat (20), each extending outwardly from opposite side walls of the container (10); 4. Apparatus according to claim 3, characterized in that the article (27) is adapted to be introduced into the gas phase chamber via it for heating and soldering. 6. The at least one nozzle (24, 26) can adjust the distance from the opposing surface of the article (27) conveyed in the gas phase chamber and the angle of the solder flow injected onto the article surface. The device according to claim 1, characterized in that: 7. The means (12, 14) for generating steam comprises a means for controlling the temperature of the steam for heating the article (27) to a certain temperature at least to a temperature at which the article is soldered before soldering. A soldering device according to claim 3, characterized in that: 8. Further comprising means (38, 64) for maintaining the article (27) in a predetermined orientation as it moves past said one or more nozzles (24, 26). Apparatus according to claim 3, characterized in that: 7.9. Said means for maintaining comprises a guiding means (38) arranged in said container (10) and a double guiding means ( 9. Device according to claim 8, characterized in that it comprises means (64) for biasing into engagement with (38). 10. Said retaining means are arranged in said container (10) and include a downwardly inclined passageway (40) at the inlet of said container (10) and a straight line in the remainder of said container (10). said one or more solder nozzles (24,
9. Apparatus according to claim 8, characterized in that 26) are arranged along said straight upward 1ill path. 11. The conveying means (22) includes a pair of conveyor chains (31, 32) arranged along the conveyor path in the container (10) and frames (34) that are adjacent to each other.
The conveyor chain (31, 3
4. Device according to claim 3, characterized in that it comprises a plurality of frames (34) connected to 2) and holding articles (27) therein. 12. One or more of the above nozzles (24, 26
) are each transported through the gas phase chamber (2).
7) The mounting M2 13 according to claim 3, wherein the distance from the opposing surface and the angle of the solder flow injected onto the surface of the article can be adjusted. or more nozzles (24, 26
) are each transported through the gas phase chamber (2).
7) The device according to claim 3, wherein the distance from the opposing surface is adjustable. 146 one or more nozzles (24, 26
4. The apparatus according to claim 3, wherein the angle of the solder flow injected onto the surface of the article can be adjusted. 15. A container (10) defining a gas phase chamber, means for generating heated saturated inert vapor in said chamber at a temperature for heating the circuit board (27) at a temperature prior to solder application ( 12, 14), an inlet throat (18) and an outlet throat (20) each extending outwardly from opposite side walls of said container (10);
, a circuit board (27) comprising means (22) for conveying a circuit board Fi (27) through the inlet throat (18), the gas phase chamber of the container (10) and the outlet throat (20); an apparatus for soldering, comprising: molten solder 1 (30); coupled to the solder source (30) and disposed within the gas phase chamber; one or more nozzles (24, 2) acting to direct the circuit board (27);
6), and the inlet and outlet throats (18, 20) are connected to the container (IO) and the inlet and outlet throats for heating and soldering the circuit board (27) in the gas phase chamber. A device characterized in that it forms a substantially direct current conveying path through (18, 20). 16. The vapor generating means includes a heater (12) at the bottom of the container (10) for heating the vapor phase liquid (14) to generate saturated inert vapor within the vapor phase chamber.
16. The device according to claim 15, characterized in that it comprises: 17. The container (10) is arranged around the container wall,
17. Device according to claim 16, characterized in that it comprises a cooling coil (16) located at a position defining the upper limit of vapor in the vapor chamber. 18. an elongated cylindrical member (50) in which each nozzle (24, 26) has an elongated linear orifice (52) of sufficient length to supply solder flow across the entire width of the circuit board (27); , 1! . piping means (60, 62) for coupling the cylindrical member (50) to the solder source (30) and supplying molten solder to the cylindrical member (50) and the orifice (52); 16. The device according to claim 15, characterized in that it comprises: 19. Claim 1, characterized in that each elongated linear orifice (52) is adjustable in a direction perpendicular to its length to further control solder flow.
The device according to item 9. 20, a container (10) defining a gas phase chamber, and providing a zone of saturated inert vapor within said chamber at an elevated temperature selected to heat the article (27) to a predetermined temperature prior to solder application. In an apparatus for soldering articles (27) comprising means for forming (12, 14) and means for transporting articles (27) into and out of said vapor zone along a travel path, a source of molten solder ( 30) coupled to the solder source (30) and disposed within the vapor zone and each directing a flow of molten solder onto the heated article (27); Apparatus characterized in that it comprises one or more solder nozzles (24, 26) operative to apply solder to the article. 21, at least one pair of the nozzles (24, 26),
21. Apparatus according to claim 20, characterized in that it is arranged astride the article movement path so as to direct the flow of molten solder to opposite surfaces of the heated article (27). 22. Claim No. 2, characterized in that the heating of the article (27) before solder application and the application of solder are individually controllable and substantially independent of other controls. The device according to paragraph 20. 23. Device according to claim 20, characterized in that the nozzles (24, 26) are individually controllable to effect the desired application of solder. 0 24. The apparatus according to claim 20, further comprising means for returning excess solder not attached to the article (27) to the solder a (30). 25. Device according to claim 20, characterized in that the solder source (30) is arranged in the vapor zone. 26. Device according to claim 20, characterized in that the path of movement of the article (27) is a continuous, substantially direct current path. 27. forming a zone of saturated inert steam at a selected elevated temperature; transporting articles into and out of the steam zone along a path of movement; and introducing steam articles into the steam of the steam zone. Soldering an article by heating the article to a predetermined temperature by exposing the article to the predetermined temperature, after heating the article to the predetermined temperature and before removing the article from the steam zone, the heated article is heated to a predetermined temperature. 1 of solder dissolved in
or (1) applying solder to the article by directing one or more flows. 28. The method of claim 27, wherein the path of movement is a continuous, substantially direct current path. 29. The predetermined temperature at which the article is heated is at or above the temperature of the solder paste applied to the article when the article is brought into the steam zone, and 28. The method of claim 27, further comprising the step of exposing the solder to the vapor of the vapor zone, thereby reflowing the solder. 30. The method of claim 33, further comprising the step of individually controlling each solder stream to provide the desired application of solder. )