Wave soldering equipment

Abstract

To provide a jet soldering device capable of more reliably soldering a substrate. The jet soldering device has a storage tank 110 for storing molten solder S, and a supply unit 125 having a plurality of nozzles 127 for supplying the molten solder S. The height of the nozzles 127 is 3 mm or more and 10 mm or less.

Description

[Technical field]

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

[0002] A jet soldering apparatus for supplying molten solder to a board has been known for some time. For example, Patent Document 1 discloses a jet soldering tank that performs soldering by jetting molten solder to contact the board, and shows that the jet soldering tank 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 in the board transport direction and jets molten solder by a second jet pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-114718 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional jet soldering devices, there are cases where soldering to a board cannot be performed reliably.

[0005] The present invention provides a jet soldering apparatus that can perform soldering on a board more reliably. [Means for solving the problem]

[0006] [Concept 1] The wave soldering apparatus according to the present invention comprises: a storage tank for storing molten solder; a supply unit having a plurality of nozzles for supplying the molten solder; Equipped with The height of the nozzle may be between 3 mm and 10 mm.

[0007] [Concept 2] In the wave soldering apparatus according to concept 1, A centre-to-centre spacing between the nozzles in a substrate transport direction may be greater than a centre-to-centre spacing between the nozzles in a direction perpendicular to the substrate transport direction.

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

[0009] [Concept 4] A wave soldering apparatus according to any one of claims 1 to 3, The nozzle may have a height of 5mm or more.

[0010] [Concept 5] A wave soldering apparatus according to any one of claims 1 to 4, The nozzle may have a height of 7mm or less.

[0011] [Concept 6] A wave soldering apparatus according to any one of claims 1 to 5, The center-to-center spacing between the plurality of nozzles may be between 9 mm and 20 mm.

[0012] [Concept 7] A wave soldering apparatus according to any one of claims 1 to 6, The plurality of nozzles may be arranged in a plurality of rows in the substrate transport direction, and the height of the nozzles in the final row in the substrate transport direction may be lower than the height of the nozzles in the other rows.

[0013] [Concept 8] A wave soldering apparatus according to any one of claims 1 to 7, The molten solder may contain 35 mass % or more of Bi.

[0014] [Concept 9] A wave soldering apparatus according to any one of claims 1 to 8, The height positions of the plurality of nozzles may be adjustable. Effect of the Invention

[0015] In the present invention, by adopting an embodiment in which the nozzle height is 3 mm or more, soldering to the board can be performed more reliably, and by setting the nozzle height to 10 mm or less, oxidation of the solder can be prevented. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing a soldering apparatus according to the present embodiment. [Diagram 2] FIG. 2 is a side cross-sectional view showing an embodiment in which the nozzles in the first supply section are all at the same height in the jet soldering apparatus according to the present embodiment. [Diagram 3] FIG. 3 is a plan view showing an example of the jet soldering apparatus according to the present embodiment. [Figure 4] FIG. 4 is a perspective view showing a plurality of nozzles in the first supply section according to the present embodiment. [Diagram 5] FIG. 5 is a side cross-sectional view showing one nozzle according to this embodiment. [Figure 6] FIG. 6 is a diagram showing a plurality of nozzles in the first supply section according to the present embodiment as viewed from the bottom side. [Figure 7] Figure 7 is a side cross-sectional view showing an embodiment of the jet soldering apparatus in which the height of the nozzles in the final row (third row) of nozzles in the first supply section is lower than the heights of the nozzles in the first and second rows. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Embodiment "composition" The soldering device shown in FIG. 1 is a device that performs a soldering process on a board 200 on which electronic components such as semiconductor elements, resistors, and capacitors are mounted on a circuit. Typically, the electronic components are positioned below the board 200. The soldering device has a main body 1 and a conveying section 5 that conveys the board 200. The main body 1 has an inlet 2 for conveying the board 200 and an outlet 3 for conveying the board 200. The board 200 may be conveyed at 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 of the board conveying direction A is positioned higher than the upstream side. However, this is not limited to this, and the board 200 may be conveyed horizontally, for example. The conveying section 5 may have a conveying drive section (not shown) that imparts a driving force for conveying the board 200, and a conveying rail 6 that guides the board 200.

[0018] As shown in FIG. 1, the main body 1 may be provided with a fluxer 10 for applying flux to the board 200, a preheater section 15 for preheating the board 200 to which the flux has been applied, a jet soldering device 100 for jetting molten solder to contact the board 200, and a cooler 20 for cooling the soldered board 200. The board 200 transported along the transport rail 6 of the transport section 5 passes through the fluxer 10, the preheater section 15, the jet soldering device 100, and the cooler 20 in order. The jet soldering device 100 may have a control section 50 for giving commands to each component to control them, a storage section 60 for storing various information, and an operation section 70 for an operator to input various information to operate the soldering device. In FIG. 1, the soldering device is shown in a top plan view except for the control section 50, the storage section 60, and the operation section 70.

[0019] The fluxer 10 is used to apply flux to the transported substrate 200. The flux may contain a solvent, an activator, and the like. The fluxer 10 may be provided with a plurality of application devices. Different types of flux may be used depending on the type of solder and the type of substrate 200.

[0020] The preheater section 15 heats the substrate 200, thereby raising the temperature of the substrate 200 uniformly to a predetermined temperature. By heating the substrate 200 in this manner, solder is more likely to adhere to predetermined locations of the substrate 200. For example, a far-infrared panel heater is used as the preheater section 15. The far-infrared panel heater can rapidly heat the substrate 200 to a set temperature. Also, the substrate 200 may be heated by blowing gas (hot air) heated by the heater onto the substrate 200 using a fan. Also, a halogen heater or the like may be used as the preheater section 15.

[0021] The cooler 20 has a cooling fan (not shown) and cools the board 200 that has been soldered by the jet soldering apparatus 100. The cooling fan may be controlled only by turning it on and off, or the air speed may be adjusted. The cooler 20 may be a chiller or the like that cools the board 200 to a predetermined temperature.

[0022] The control unit 50 shown in FIG. 1 is communicatively connected to the transport unit 5 including the transport rail 6, the fluxer 10, the preheater unit 15, the jet soldering device 100, the cooler 20, the operation unit 70, and the memory unit 60. The communicative connections include both wired and wireless connections. The operation unit 70 may have a liquid crystal display panel or a numeric keypad, and is typically a personal computer, a smartphone, a tablet, or the like. When an operator operates the operation unit 70, the control unit 50 may control the transport speed of the transport unit 5, the timing of transporting the board 200, the temperature of the flux in the fluxer 10, the amount of flux applied, the temperature of the preheater unit 15, the temperature of the molten solder S of the jet soldering device 100, the jet flow rate, the jet speed, ON / OFF of the cooling fan of the cooler 20, and the like. The memory unit 60 may store information inputted by the operation unit 70, instructions from the control unit 50, the operating time of the jet soldering device 100, and the like.

[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 this 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 jetted from the first supply unit 120 and the second supply unit 130 is jetted from below to above. The molten solder S that has received the driving force from the first pump 141 is pumped through the duct and jetted toward the substrate 200, and the solder adheres to a predetermined location on the substrate 200. Similarly, the molten solder S that has received the driving force from the second pump 146 is pumped through the duct and jetted toward the substrate 200, and the 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 for use. In this case, the molten solder S may be circulated through a filter (not shown). Although the first pump 141 and the second pump 146 are typically each composed of one pump, 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 board 200 with force. The second openings 136 of the second supply unit 130 are used to supply the molten solder S to the board 200 with a weaker force than the first supply unit 120. The jet solder supplied from the first supply unit 120 is a dynamic supply that causes the molten solder S to collide with the board 200 with force, and is a supply for spreading the molten solder S to every corner of the board 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 the solder to the electrodes of the board 200 by passing through the molten solder S consisting of a gentle flow.

[0025] As shown in FIG. 2, the first supply unit 120 has a first housing 121 and one or more first openings 126 that are provided on the upper surface of the first housing 121 and supply the molten solder S. In this embodiment, the first opening 126 has a nozzle shape that protrudes upward from the upper surface of the first housing 121. The second supply unit 130 has a second housing 131 and one or more second openings 136 that are provided on the upper surface of the second housing 131 and supply the molten solder S. The first housing 121 and the second housing 131 may be provided separately, or may be provided integrally. In this embodiment, as an example, the first opening 126 consisting of a plurality of nozzles 127 and one slit-shaped second opening 136 will be described (see FIG. 3, etc.). However, the present invention is not limited to this embodiment, and for example, a plurality of slit-shaped second openings 136 may be provided, and in this case, a plurality of slit-shaped second openings 136 may be provided in a manner extending in parallel. The second opening 136 may also be made of a plurality of nozzles. In the present embodiment, the following description will be given using an embodiment in which the first opening 126 is made up of a plurality of nozzles, but when the second opening 136 is made up of a plurality of nozzles, any embodiment described for the nozzle 127 which is the first opening 126 can be adopted for the nozzle. The shape of the nozzle does not have to be cylindrical, and may be, for example, a polygonal prism such as a triangular prism or a square prism, or may be another shape (for example, the cross section of the opening may be elliptical, cross, or star-shaped). The cross-sectional area of ​​the nozzle is 9π to 25π mm 2 (approx. 28.26~78.5mm 2 ) can also be used.

[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 manner may be configured not to be separated from the substrate 200 transported by the transport unit 5 between the first supply unit 120 and the second supply unit 130. The substrate 200 is supported and transported by the transport rail 6, and the upper surface of the mixed molten solder S may not be positioned lower than the lower end of the transport rail 6 transporting the substrate 200 when viewed from the side in the entire length region along the substrate transport 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 transported by the transport 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 sprayed to a position higher than the transport position of the substrate 200, but this is not limited to such an embodiment. 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 come into contact with the substrate 200 may be provided, and the molten solder S may be sprayed in two clearly separated stages.

[0028] The temperature of the molten solder S is generally about the melting temperature of the solder + 50°C. In recent years, there has been an increasing need to lower the working temperature in order to reduce damage to components and reduce machine power consumption. In addition, the market prices of Sn and Ag have risen sharply, and the use of solder that does not use these metals has also been considered. Typically, the use of Sn-58Bi (melting point 139°C) instead of Sn-3Ag-0.5Cu (melting point 217°C) has been considered. Sn-58Bi is a low-temperature eutectic solder. Note that, when Sn-58Bi is used, soldering can be performed at a temperature of 200°C or less. 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. Sn-58Bi also has the property of being easily oxidized. These tendencies are seen in solders containing Bi, and are particularly noticeable in solders containing 35 mass% or more of Bi.

[0029] In this embodiment, the height of nozzle 127 in first supply unit 120 is 3 mm or more and 10 mm or less (see FIG. 4). The inventors of the present application confirmed that by setting the height of nozzle 127 to 3 mm or more, the molten solder S ejected from nozzle 127 can be formed into a bead shape, and the molten solder S can be firmly attached to substrate 200. Furthermore, if the height of nozzle 127 is too high, oxidation tends to occur when the molten solder S falls, so it is preferable to set the height of nozzle 127 to 10 mm or less. In FIG. 5, H1 is the height of nozzle 127, and H2 is a value including the thickness of the top surface of first supply unit 120.

[0030] In order to improve the effect of forming the ejected molten solder S into a bead shape, the height of the nozzle 127 is preferably 4 mm or more, and more preferably 5 mm or more. In order to prevent the molten solder S from being oxidized when it falls, the height of the nozzle 127 is preferably 8 mm or less, and more preferably 7 mm or less.

[0031] Nozzle 127 may be of a screw type or a slide type, and its height position may be adjustable. When such an embodiment is adopted, the height position of nozzle 127 can be adjusted according to, for example, the type of substrate 200. Note that the adjustment range in this case may be about 0.1 mm to 3 mm.

[0032] As described above, solder containing Bi tends to have a weak surface tension, so an embodiment in which the height of the nozzle 127 is 3 mm or more is particularly beneficial when using solder containing Bi. Also, solder containing Bi has a high tendency to oxidize, so an embodiment in which the height of the nozzle 127 is 10 mm or less is particularly beneficial when using solder containing Bi. Also, this tendency is stronger in solder containing 35 mass % or more of Bi, so it is very beneficial to use this embodiment in solder containing 35 mass % or more of Bi, such as Sn-58Bi.

[0033] 3, 4, and 6, the multiple nozzles 127 may be arranged in three rows in the substrate transport direction A. When arranged in four or more rows, if the nozzles 127 are spaced apart to a certain extent, the length (length in the short direction) of the first supply section 120 in the substrate transport direction A becomes long. However, when arranged in three rows, the nozzles 127 can be spaced apart to a certain extent while preventing the length of the first supply section 120 in the substrate transport direction A from becoming too long.

[0034] The center-to-center spacing between the multiple nozzles 127 is preferably 9 mm or more and 20 mm or less. If the center-to-center spacing is less than 9 mm, the distance of the molten solder S ejected from the nozzle 127 becomes shorter, and the bead shape of the molten solder S may become distorted. If the bead shape of the molten solder S becomes distorted in this manner, the effect of the molten solder S adhering to the substrate 200 is reduced. On the other hand, if the center-to-center spacing exceeds 20 mm, the amount of molten solder S supplied per unit area becomes smaller, 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 conveying 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 perpendicular to the substrate conveying direction A (the longitudinal 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 longer than the center-to-center distance D1 between the nozzles 127 in the longitudinal direction. The center-to-center distance D2 between the nozzles 127 in the short side direction may be 1.1 times or more, or may be 1.2 times or more, the center-to-center distance D1 between the nozzles 127 in the longitudinal direction. By adopting such an embodiment, it is expected that the amount of solder supplied by the multiple nozzles 127 arranged in the longitudinal direction (the direction perpendicular to the substrate conveying direction A) can be maintained, while preventing the bead shape of the solder supplied from the nozzles 127 from being destroyed by the solder from the nozzles 127 adjacent in the short side direction as much as possible.

[0036] It is also possible to adopt a mode in which the height of the nozzle 127 in the final row in the substrate transport direction A (the nozzle 127 at the right end in FIG. 7) is lower than the height of the nozzles 127 in the other rows. The inventors of the present application have confirmed that if bead-shaped solder can be supplied to the substrate 200 on the upstream side of the substrate transport direction A, the solder can be efficiently attached to the substrate 200. On the other hand, even if the height of the nozzle 127 in the final row in the substrate transport direction A is increased, it may not be possible to supply bead-shaped solder due to the molten solder S supplied from the second supply unit. Therefore, it may be beneficial to reduce the height of the nozzle 127 in the final row in the substrate transport direction A to avoid inconvenience caused by oxidation of the molten solder S.

[0037] In addition, in order to promote the separation of dross generated by the oxidation of the solder, it is possible to provide the molten solder S with an oxidation separating agent such as rice bran, wheat bran, beans, sesame, sunflower, palm, rapeseed, vegetable oil, sugars such as wood flour, pine resin, ammonium chloride, amine halides, etc.

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

[0039] When an operator places the substrate 200 on the transport rail 6, the transport section 5 transports the substrate 200, and the substrate 200 is carried into the main body section 1 through the carry-in entrance 2. When the substrate 200 reaches above the fluxer 10, the fluxer 10 applies flux to a predetermined location of the substrate 200.

[0040] The transport section 5 transports the substrate 200, on which the flux has been applied by the fluxer 10, to the preheater section 15. The preheater section 15 heats the substrate 200 to a predetermined temperature.

[0041] Next, the conveying section 5 conveys the board 200 heated to a predetermined temperature by the preheater section 15 to the jet soldering device 100. The jet soldering device 100 solders a predetermined portion of the board 200. While the jet soldering device 100 supplies the molten solder S, the molten solder S supplied from the first supply section 120 and the molten solder S supplied from the second supply section 130 are mixed together, and the molten solder S is supplied above the conveying rail 6. At this time, the height of the nozzle 127 in the first supply section 120 is 3 mm or more, so that the molten solder S sprayed from the nozzle 127 can form a bead shape, and the molten solder S can be firmly attached to the board 200. In addition, by setting the height of the nozzle 127 to 10 mm or less, the molten solder S can be prevented from being oxidized. As mentioned above, solder containing Bi (especially solder containing 35% or more by mass of Bi, such as Sn-58Bi) has a small surface tension, so the solder supplied from first supply section 120 is unlikely to form a bead shape and is easily oxidized, making it extremely beneficial to adopt the aspect of this embodiment.

[0042] Next, the conveying unit 5 conveys the soldered board 200 to the cooler 20. For example, a cooling fan of the cooler 20 cools the soldered board 200 for a predetermined time. After the board 200 has been cooled, the conveying unit 5 ejects the board 200 from the discharge port 3, and the soldering process on the board 200 is completed. EXAMPLES

[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 locations where solder was not attached. In Comparative Example 2, the amount of dross generated in the molten solder S was significantly increased.

[0047] The above-mentioned description of each embodiment and the disclosure of 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 description of each embodiment or the disclosure of the drawings. In addition, the description of the claims at the time of filing is merely an example, and the description of the claims may be appropriately changed based on the description of the specification, drawings, etc. [Explanation of symbols]

[0048] 110 Reservoir 120 First supply section (supply section) 127 Nozzle 130 Second supply section (supply section) 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; Equipped with The height of all of the plurality of nozzles is equal to or greater than 3 mm and equal to or less than 8 mm; A jet soldering apparatus, wherein the center-to-center spacing between the plurality of nozzles is 9 mm or greater but less than 20 mm.

2. a storage tank for storing molten solder; a supply unit having a plurality of nozzles for supplying the molten solder; Equipped with The height of the nozzle is 3 mm or more and 10 mm or less, all of said plurality of nozzles have the same height; A jet soldering apparatus, wherein the center-to-center spacing between the plurality of nozzles is 9 mm or greater but less than 20 mm.

3. a storage tank for storing molten solder; a supply unit having a plurality of nozzles for supplying the molten solder; Equipped with The height of the nozzle is 3 mm or more and 10 mm or less, The plurality of nozzles are arranged in a plurality of rows in a board transport direction, and the height of the nozzles in the final row in the board transport direction is lower than the height of the nozzles in the other rows.

4. 4. The jet soldering apparatus according to claim 1, wherein the plurality of nozzles are arranged in three rows in a board transport direction.

5. 4. The jet soldering apparatus according to claim 1, wherein the nozzle has a height of 5 mm or more.

6. 4. The jet soldering apparatus according to claim 1, wherein the nozzle has a height of 7 mm or less.

7. 4. The jet soldering apparatus according to claim 1, wherein the center-to-center spacing between the plurality of nozzles is 9 mm or more and 20 mm or less.

8. 4. The jet soldering apparatus according to claim 1, wherein the molten solder contains 35 mass % or more of Bi.

9. 4. The jet soldering device according to claim 1, wherein the height positions of said plurality of nozzles are adjustable.

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