Jet soldering equipment

Abstract

To provide jet soldering equipment that can solder to a substrate more reliably.SOLUTION: Jet soldering equipment has a reservoir 110 for storing molten solder S and a supply section 125 with a plurality of nozzles 127 for supplying the molten solder S. The height of the nozzle 127 is equal to or more than 3 mm and equal to or less than 10 mm.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a jet soldering apparatus that supplies molten solder to a substrate.

Background Art

[0002] Conventionally, a jet soldering apparatus for supplying molten solder to a substrate has been known. For example, Patent Document 1 discloses a jet solder bath that performs soldering by jetting molten solder and bringing it into contact with a substrate. The jet solder bath includes a first jet nozzle that jets molten solder by a first jet pump, and a second jet nozzle that is disposed downstream of the first jet nozzle with respect to the conveyance direction of the substrate and jets molten solder by a second jet pump.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional jet soldering apparatus, soldering to a substrate may not be performed reliably.

[0005] The present invention provides a jet soldering apparatus that can perform soldering to a substrate more reliably.

Means for Solving the Problems

[0006] [Concept 1] The jet soldering apparatus according to the present invention includes a storage tank that stores molten solder, a supply unit having a plurality of nozzles for supplying the molten solder, and The height of the nozzle may be 3 mm or more and 10 mm or less.

[0007] [Concept 2] In the jet soldering apparatus according to Concept 1, The center-to-center distance between the nozzles in the substrate conveyance direction may be longer than the center-to-center distance between the nozzles in the direction orthogonal to the substrate conveyance direction.

[0008] [Concept 3] In the jet soldering apparatus according to Concept 1 or 2, The plurality of nozzles may be arranged in three rows in the substrate conveyance direction.

[0009] [Concept 4] In the jet soldering apparatus according to any one of Concepts 1 to 3, The height of the nozzle may be 5 mm or more.

[0010] [Concept 5] In the jet soldering apparatus according to any one of Concepts 1 to 4, The height of the nozzle may be 7 mm or less.

[0011] [Concept 6] In the jet soldering apparatus according to any one of Concepts 1 to 5, The center-to-center distance between the plurality of nozzles may be 9 mm or more and 20 mm or less.

[0012] [Concept 7] In the jet soldering apparatus according to any one of Concepts 1 to 6, The plurality of nozzles are arranged in a plurality of rows in the substrate conveyance direction, and the height of the nozzles in the last row in the substrate conveyance direction may be lower than the height of the nozzles in the other rows.

[0013] [Concept 8] In the jet soldering apparatus according to any one of Concepts 1 to 7, The molten solder may contain 35 mass% or more of Bi.

[0014] [Concept 9] In the jet soldering apparatus according to any one of Concepts 1 to 8, the heights of the plurality of nozzles may be adjustable.

Advantages of the Invention

[0015] In the present invention, by adopting the aspect of setting the height of the nozzle to 3 mm or more, soldering to the substrate can be performed more reliably. Further, by setting the height of the nozzle to 10 mm or less, oxidation of the solder can be prevented.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0017] Embodiment "Configuration" The soldering apparatus shown in Fig. 1 is, for example, an apparatus for performing soldering on a substrate 200 on which electronic components such as semiconductor elements, resistors, and capacitors are mounted on a circuit board. Typically, the electronic components and the like are positioned below the substrate 200. The soldering apparatus has a main body 1 and a conveying unit 5 for conveying the substrate 200. The main body 1 has a loading port 2 for loading the substrate 200 and an unloading port 3 for unloading the substrate 200. The conveyance of the substrate 200 may be performed with a predetermined angle, for example, an inclination of about 3 to 6 degrees as viewed from the side (see Fig. 2). In this case, the downstream side is positioned higher than the upstream side in the substrate conveyance direction A. However, it is not limited to this, and the conveyance of the substrate 200 may be performed horizontally, for example. The conveying unit 5 may have a conveying drive unit (not shown) for applying a driving force for conveying the substrate 200 and a conveying rail 6 for guiding the substrate 200.

[0018] As shown in Fig. 1, the main body 1 may be provided with a fluxer 10 for applying flux to the substrate 200, a preheater unit 15 for preheating the substrate 200 to which the flux has been applied, a jet soldering apparatus 100 for jetting molten solder and bringing it into contact with the substrate 200, and a cooler 20 for cooling the soldered substrate 200. The substrate 200 conveyed along the conveying rail 6 of the conveying unit 5 passes through the fluxer 10, the preheater unit 15, the jet soldering apparatus 100, and the cooler 20 in this order. The jet soldering apparatus 100 may have a control unit 50 for giving commands to and controlling each component, a storage unit 60 for storing various information, and an operation unit 70 for operating the soldering apparatus by an operator inputting various information. In Fig. 1, except for the control unit 50, the storage unit 60, and the operation unit 70, the soldering apparatus is shown in an upper plan view.

[0019] The fluxer 10 is used to apply flux to the conveyed substrate 200. The flux may contain a solvent, an activator, and the like. The fluxer 10 may be provided with a plurality of coating devices. The type of flux may be selectively used according to the type of solder and the type of the substrate 200.

[0020] The preheater unit 15 heats the substrate 200 to uniformly raise the temperature of the substrate 200 to a predetermined temperature. When the substrate 200 is heated in this way, solder is likely to adhere to a predetermined location on the substrate 200. As the preheater unit 15, for example, a far-infrared panel heater is used. The far-infrared panel heater can rapidly heat the substrate 200 to the set temperature. Also, heated gas (hot air) by the heater may be blown onto the substrate 200 by a fan to heat the substrate 200. Further, as the preheater unit 15, a halogen heater or the like may be used.

[0021] The cooler 20 has a cooling fan (not shown) and cools the substrate 200 that has been soldered by the jet soldering apparatus 100. The control of the cooling fan may be only ON and OFF, or the wind speed may be adjusted or the like. Further, as the cooler 20, a chiller or the like may be used to cool the substrate 200 until it reaches a predetermined temperature.

[0022] The control unit 50 shown in FIG. 1 is communicably connected to the transport unit 5 including the transport rail 6, the fluxer 10, the preheater unit 15, the jet soldering apparatus 100, the cooler 20, the operation unit 70, and the storage unit 60. The communicable connection includes both wired and wireless means. The operation unit 70 may have a liquid crystal display panel, numeric keypad, etc., and is typically a personal computer, smartphone, tablet, etc. By the operator operating the operation unit 70, the control unit 50 controls the transport speed by the transport unit 5, the timing of transporting the substrate 200, the temperature of the flux at the fluxer 10, the application amount of the flux, the temperature of the preheater unit 15, the temperature of the molten solder S of the jet soldering apparatus 100, the jet flow amount, the jet flow speed, the ON and OFF of the cooling fan of the cooler 20, etc. The storage unit 60 may store the information input by the operation unit 70, the instructions of the control unit 50, the operating time of the jet soldering apparatus 100, etc.

[0023] As shown in FIG. 2, the jet soldering apparatus 100 has a storage tank 110 for storing the molten solder S and a supply unit for supplying the molten solder S to the substrate 200. In the present embodiment, the supply unit has a first supply unit 120 and a second supply unit 130. The first supply unit 120 may have a first pump 141 which is a first driving unit. Similarly, the second supply unit 130 may have a second pump 146 which is a second driving unit. The molten solder S ejected from the first supply unit 120 and the second supply unit 130 is ejected upward from below. The molten solder S receiving the driving force from the first pump 141 is pumped through the duct, ejected toward the substrate 200, and solder adheres to a predetermined location on the substrate 200. Similarly, the molten solder S receiving the driving force from the second pump 146 is pumped through the duct, ejected toward the substrate 200, and solder adheres to a predetermined location on the substrate 200. The molten solder S is heated to a temperature of, for example, about 180°C to 250°C by a heater (not shown). The molten solder S supplied from the first supply unit 120 and the second supply unit 130 may be circulated and utilized. In this case, it may be circulated through a filter (not shown). The first pump 141 and the second pump 146 are typically each composed of one pump, but the first pump 141 and the second pump 146 may each be composed of a plurality of pumps.

[0024] The first supply unit 120 of the jet soldering apparatus 100 shown in FIG. 2 has a plurality of first openings 126 (see FIG. 3 etc.). The plurality of first openings 126 are used to supply a large amount of molten solder S to the substrate 200 vigorously. The second opening 136 of the second supply unit 130 is used to supply the molten solder S to the substrate 200 with a weaker force compared to the first supply unit 120. The jet solder supplied from the first supply unit 120 is a dynamic supply that vigorously collides the molten solder S against the substrate 200 and is a supply for spreading the molten solder S to every corner of the substrate 200. On the other hand, the jet solder supplied from the second supply unit 130 is a static supply and is a supply for neatly attaching solder to the electrodes etc. of the substrate 200 by passing through the molten solder S consisting of a gentle flow.

[0025] As shown in FIG. 2, the first supply unit 120 includes a first housing 121 and one or a plurality of first openings 126 provided on the upper surface of the first housing 121 for supplying the molten solder S. In the present embodiment, the first opening 126 has a nozzle shape protruding upward from the upper surface of the first housing 121. The second supply unit 130 includes a second housing 131 and one or a plurality of second openings 136 provided on the upper surface of the second housing 131 for supplying the molten solder S. The first housing 121 and the second housing 131 may be provided separately, or they may be provided integrally. In the present embodiment, as an example, the first opening 126 composed of a plurality of nozzles 127 and one slit-shaped second opening 136 will be described (see FIG. 3 and the like). However, it is not limited to such a mode. For example, a plurality of slit-shaped second openings 136 may be provided. In this case, the plurality of slit-shaped second openings 136 may be provided in a manner of extending in parallel. Also, the second opening 136 may be composed of a plurality of nozzles. In the present embodiment, the mode in which the first opening 126 is composed of a plurality of nozzles will be described hereinafter. When the second opening 136 is composed of a plurality of nozzles, in the nozzles, any mode described for the nozzle 127 which is the first opening 126 can be adopted. Note that the shape of the nozzle does not necessarily have to be a cylindrical shape. For example, it may be a polygonal prism shape such as a triangular prism or a quadrangular prism, or other shapes (for example, the cross section of the opening may be an elliptical shape, a cross shape, or a star shape). Also, the area of the cross section of the nozzle is 9π~25π mm 2 (about 28.26~78.5 mm 2 ) is also acceptable.

[0026] While the molten solder S is being supplied, the molten solder S supplied from the first supply unit 120 and the molten solder S supplied from the second supply unit 130 may be mixed. The molten solder S mixed in this way may be configured not to be separated from the substrate 200 conveyed by the conveying unit 5 between the first supply unit 120 and the second supply unit 130. The substrate 200 will be supported by the conveying rail 6 and conveyed, but the upper surface of the mixed molten solder S may not be positioned below the lower end of the conveying rail 6 that conveys the substrate 200 when viewed from the side in the entire length region along the substrate conveying direction A between the first supply unit 120 and the second supply unit 130. In this case, the molten solder S is configured not to be separated from the substrate 200 conveyed by the conveying unit 5 between the first supply unit 120 and the second supply unit 130.

[0027] The molten solder S supplied from the first supply unit 120 and the molten solder S supplied from the second supply unit 130 may be integrated and ejected to a position higher than the conveyance position of the substrate 200, but it is not limited to such a mode. Between the molten solder S supplied from the first supply unit 120 and the molten solder S supplied from the second supply unit 130, a location where the molten solder S does not contact the substrate 200 may be provided, and the molten solder S may be ejected in a mode clearly divided into two stages.

[0028] The temperature of the molten solder S is generally about the melting temperature of the solder + 50°C. In recent years, due to the reduction of component damage and the reduction of mechanical power consumption, the need to lower the working temperature has been increasing. Also, the prices of Sn and Ag have been soaring, and the use of solders that do not contain these has been considered. Typically, instead of Sn-3Ag-0.5Cu (melting point 217°C), Sn-58Bi (melting point 139°C) has been considered for use. Sn-58Bi is a low-temperature eutectic solder. Note that when using Sn-58Bi, soldering can be performed at a temperature of 200°C or lower. On the other hand, since Sn-58Bi has a small surface tension, the solder supplied from the nozzle 127 of the first supply unit 120 tends not to form a bead shape. Also, Sn-58Bi has the property of being easily oxidized. These tendencies are observed in solders containing Bi, and are particularly prominent in solders containing 35 mass% or more of Bi.

[0029] In the present embodiment, the height of the nozzle 127 in the first supply unit 120 is 3 mm or more and 10 mm or less (see Fig. 4). As a result of the inventors of the present application confirming that the height of the nozzle 127 is 3 mm or more, the molten solder S ejected from the nozzle 127 can form a bead shape, and the molten solder S can be firmly attached to the substrate 200. Also, since oxidation tends to occur when the molten solder S falls if the height of the nozzle 127 is too high, it is preferable that the height of the nozzle 127 is 10 mm or less. H1 in Fig. 5 is the height of the nozzle 127, and H2 is the value including the thickness of the top surface of the first supply unit 120.

[0030] In order to enhance the effect of making the ejected molten solder S into a bead shape, it is preferable that the height of the nozzle 127 is 4 mm or more, and more preferably 5 mm or more. In terms of preventing oxidation when the molten solder S falls, it is preferable that the height of the nozzle 127 is 8 mm or less, and more preferably 7 mm or less.

[0031] The nozzle 127 may be screw-type or slide-type, and its height position may be adjustable. When such an aspect is adopted, for example, the height position of the nozzle 127 can be adjusted according to the type of the substrate 200. In addition, the adjustment range at this time may be about 0.1 mm to 3 mm.

[0032] As described above, in the solder containing Bi, since the surface tension tends to be weak, the aspect of setting the height of the nozzle 127 to 3 mm or more is particularly beneficial when using the solder containing Bi. Further, in the solder containing Bi, since the tendency to oxidize increases, the aspect of setting the height of the nozzle 127 to 10 mm or less is particularly beneficial when using the solder containing Bi. Further, since such a tendency becomes stronger in the solder containing 35 mass% or more of Bi, it is very beneficial to use the present embodiment in Sn-58Bi etc. containing 35 mass% or more of Bi.

[0033] As shown in FIGS. 3, 4, and 6, the plurality of nozzles 127 may be arranged in three rows in the substrate conveyance direction A. When arranging in four rows or more, if the distance between the nozzles 127 is separated to some extent, the length of the first supply unit 120 in the substrate conveyance direction A (the length in the short side direction) becomes long. However, when arranging in three rows, it is possible to prevent the length of the first supply unit 120 in the substrate conveyance direction A from becoming too long and to separate the distance between the nozzles 127 to some extent.

[0034] The center-to-center distance between the plurality of nozzles 127 is preferably 9 mm or more and 20 mm or less. When the center-to-center distance is less than 9 mm, the distance of the molten solder S ejected from the nozzle 127 becomes short, and the bead shape of the molten solder S may collapse. When the bead shape of the molten solder S collapses in this way, the effect of adhesion of the molten solder S to the substrate 200 is reduced. On the other hand, when the center-to-center distance exceeds 20 mm, the supply amount of the molten solder S per unit area becomes small, and there is a possibility that the molten solder S cannot be efficiently supplied to the substrate 200.

[0035] The center-to-center distance D2 between the nozzles 127 in the substrate transfer direction A (the short side direction of the first supply unit 120) may be different from the center-to-center distance D1 between the nozzles 127 in the direction orthogonal to the substrate transfer direction A (the long side direction of the first supply unit 120), and the center-to-center distance D2 between the nozzles 127 in the short side direction may be made longer than the center-to-center distance D1 between the nozzles 127 in the long side direction. The center-to-center distance D2 between the nozzles 127 in the short side direction may be made 1.1 times or more, or 1.2 times or more, the center-to-center distance D1 between the nozzles 127 in the long side direction. By adopting such an aspect, while maintaining the solder supply amount by the plurality of nozzles 127 arranged in the long side direction (the direction orthogonal to the substrate transfer direction A), it can be expected to prevent as much as possible the spherical shape of the solder supplied from the nozzles 127 from being disrupted by the solder from the nozzles 127 adjacent in the short side direction.

[0036] It is also possible to adopt an aspect in which the height of the nozzles 127 in the final row in the substrate transfer direction A (the rightmost nozzles 127 in FIG. 7) is lower than the height of the nozzles 127 in the other rows. As a result of confirmation by the inventors of the present application, if spherical solder can be supplied to the substrate 200 on the upstream side in the substrate transfer direction A, the solder can be efficiently adhered to the substrate 200. On the other hand, even if the height of the nozzles 127 in the final row in the substrate transfer direction A is increased, the spherical solder may not be supplied by the molten solder S supplied from the second supply unit. Therefore, it may be beneficial to lower the height of the nozzles 127 in the final row in the substrate transfer direction A to avoid the inconvenience caused by the oxidation of the molten solder S.

[0037] In addition, in order to promote the separation of dross generated by the oxidation of the solder, as an oxidation separating agent, saccharides such as rice bran, bran, wheat bran, beans, sesame, sunflower, coconut, rapeseed, vegetable oil, wood powder, etc., or rosin, ammonium chloride, halides of amines, etc. may be provided to the molten solder S.

[0038] Next, an example of the method for processing the substrate 200 will be described mainly with reference to FIG. 1.

[0039] When an operator places the substrate 200 on the transfer rail 6, the transfer unit 5 transfers the substrate 200, and the substrate 200 is carried into the main body 1 from the carry-in port 2. When the substrate 200 reaches the fluxer 10, the fluxer 10 applies flux to a predetermined location on the substrate 200.

[0040] The transfer unit 5 transfers the substrate 200 coated with flux by the fluxer 10 to the preheater unit 15. The preheater unit 15 heats the substrate 200 to a predetermined temperature.

[0041] Next, the transfer unit 5 transfers the substrate 200 heated to a predetermined temperature by the preheater unit 15 to the jet soldering device 100. The jet soldering device 100 performs soldering on a predetermined location of the substrate 200. While the jet soldering device 100 is supplying the molten solder S, the molten solder S supplied from the first supply unit 120 and the molten solder S supplied from the second supply unit 130 are in a mixed state, and the molten solder S is supplied above the transfer rail 6. At this time, since the height of the nozzle 127 in the first supply unit 120 is 3 mm or more, the molten solder S ejected from the nozzle 127 can form a bead shape, and the molten solder S can be firmly attached to the substrate 200. Also, by setting the height of the nozzle 127 to 10 mm or less, oxidation of the molten solder S can be prevented. As described above, in the solder containing Bi (especially the solder containing 35 mass% or more of Bi such as Sn-58Bi), since the surface tension is small, the solder supplied from the first supply unit 120 is difficult to form a bead shape and has a property of being easily oxidized. Therefore, it is extremely beneficial to adopt the mode of this embodiment.

[0042] Next, the transfer unit 5 transfers the soldered substrate 200 to the cooler 20. For example, the cooling fan of the cooler 20 cools the substrate 200 that has undergone the soldering process for a predetermined time. After the substrate 200 is cooled, when the transfer unit 5 discharges the substrate 200 from the carry-out port 3, the soldering process on the substrate 200 is completed.

Example

[0043] In order to confirm the effect of this embodiment, the results of an experiment (evaluation of performance in preventing unsoldered portions) conducted by the inventors of the present application will be described.

[0044] Fifteen evaluation boards (glass epoxy board (FR-4, size 215.4X140.3mm, thickness 1mm, Cu-OSP), number of soldering points: 498) were attached to a pallet mask with openings where soldering was to be performed. After that, soldering was performed on the evaluation boards attached to the pallet mask using nozzle 127 shown in Table 1 under the following soldering conditions. (Soldering conditions) Soldering device: Senju Metal "BITHUS-Wave MTF-300" Flux application device: Spray fluxer (Senju Metal "SSF-400") Flux application amount: 70 mL / m 2 Conveyor speed (conveying speed of conveying section 5): 1.2 m / min Substrate temperature (average temperature): 120℃ Solder bath temperature: 199℃ Solder alloy composition: Sn-58Bi

[0045] The evaluation board after soldering was visually observed and the solderability was evaluated according to the following criteria. In each of the examples and comparative examples, the cross section was circular and the diameter was 6 mm (cross-sectional area was 9π mm 2 ) nozzle was used. [Unsoldered evaluation] ○: No unsoldered spots (1 or less) ×: Unsoldered areas (2 or more) [Dross Increase] 〇: Dross increase within the normally acceptable range ×: Significant increase in dross [Table 1]

[0046] As shown in Comparative Example 1, when the height of the nozzle 127 was 2 mm, there were 45 locations out of 498 where no solder was attached. In Comparative Example 2, the amount of dross generated in the molten solder S was significantly increased.

[0047] The descriptions of the above-described embodiments and the disclosures in the drawings are merely examples for explaining the invention described in the claims, and the invention described in the claims is not limited by the descriptions of the above-described embodiments or the disclosures in the drawings. Also, the descriptions of the claims at the time of filing are merely examples, and based on the descriptions in the specification, drawings, etc., the descriptions of the claims can be appropriately changed.

Explanation of Signs

[0048] 110 Reservoir tank 120 First supply unit (supply unit) 127 Nozzle 130 Second supply unit (supply unit) S Molten solder

Claims

1. A storage tank for storing molten solder, A supply unit having a plurality of nozzles for supplying the molten solder, Comprising, A jet soldering apparatus wherein the height of the nozzle is 3 mm or more and 10 mm or less.

2. The jet soldering apparatus according to Claim 1, wherein the plurality of nozzles are arranged in three rows in the substrate conveyance direction.

3. The jet soldering apparatus according to Claim 1 or 2, wherein the height of the nozzle is 5 mm or more.

4. The jet soldering apparatus according to Claim 1 or 2, wherein the height of the nozzle is 7 mm or less.

5. The jet soldering apparatus according to Claim 1 or 2, wherein the center-to-center distance between the plurality of nozzles is 9 mm or more and 20 mm or less.

6. The jet soldering apparatus according to Claim 1 or 2, wherein the plurality of nozzles are arranged in a plurality of rows in the substrate conveyance direction, and the height of the nozzles in the last row in the substrate conveyance direction is lower than the height of the nozzles in the other rows.

7. The jet soldering apparatus according to Claim 1 or 2, wherein the molten solder contains 35 mass% or more of Bi.

8. The jet soldering apparatus according to Claim 1 or 2, wherein the height position of the plurality of nozzles is adjustable.

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