JPH069750U - Structure of jet nozzle of solder bath - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the soldering quality by increasing the probability of contact of the jet with the electronic components. In the range of the jet nozzle facing the substrate to be transported, an axis along the transport direction of the substrate passing through an arbitrary point in the solder jet hole intersects with at least one other solder jet hole and A jet nozzle configured so that the central axes of the solder jet holes along the substrate transport direction do not match.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure of a jet nozzle of a solder bath.

[0002]

[Prior art]

 Immersion soldering is one of the methods for soldering electronic components mounted on a board. In this method, the flux is applied to the electronic components on the substrate, the flux-coated substrate is preheated, the electronic components on the heated substrate are immersed in the jet solder to be attached, and the substrate is cooled. The parts are soldered.

FIG. 2 is a simplified diagram showing the structure of a solder bath for performing the step of. Molten solder 72 is filled in the case 71 of the solder bath, and the solder 72 flows by the rotation of the pump 73. The drive source of the pump 73 is provided by the motor 74. The flowing solder 72 blows out as a jet (turbulent wave) 76 on the nozzle surface via a jet nozzle 75 in the form of bubbles, and makes contact with electronic components on a substrate (not shown) conveyed to the jet 76. Dip) and solder.

FIG. 3 is a top view of the jet nozzle 75 shown in FIG. The arrows in the figure indicate the substrate transfer direction. A large number of solder jet holes 78 are provided in this nozzle as two rows of solder jet hole groups 76 and 77 in the substrate transport direction, and each solder jet hole 78 in the solder jet hole groups 76 and 77 is provided. The solder spouts from it.

[0005]

[Problems to be solved by the device]

 In the case of electronic parts, especially chips (chip parts), the gas that hinders soldering (or Air) may accumulate well. Therefore, as shown by arrow A in Fig. 3, if the chip on the board passes through two solder jet holes, the gas is expelled by the jet pressure of the solder jet hole that passed first, and the next jet jet The jet flow of the holes ensures reliable soldering. However, the passage area of the chip is different, and, for example, as shown by the arrow B in FIG. 3, only the first solder jet hole passes and the next solder jet hole does not pass, that is, only one solder jet hole is passed. In this case, since the gas remains accumulated in the joint, the solder will not adhere to the joint (that is, the solder will not get wet), resulting in poor contact, resulting in poor soldering quality.

An object of the present invention is to improve the soldering quality by increasing the contact probability of a jet flow with an electronic component.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a structure of a jet nozzle of a solder bath, in which solder is jetted from a large number of solder jet holes to electronic components on a substrate to be transported, The axis line along the transfer direction of the substrate passing through an arbitrary point in each solder jet hole in the range facing each other intersects with at least one or more other solder jet holes, and It is characterized in that the central axes along the transport direction are configured so as not to coincide with each other.

[0008]

[Action]

 The present invention provides a jet hole having at least one other axis along the substrate transport direction that passes through an arbitrary point in each solder jet hole within a range facing the substrate to be transported. Therefore, the electronic component can be substantially immersed in the at least two solder jet holes (jet flows), and the contact probability of the electronic component to the jet flow is increased. However, with this configuration alone, a special case may occur in which the central axes of the solder jet holes along the carrying direction of the substrate coincide, as shown in FIG. In this case, when the electronic component passes through the gap between the solder jet holes as shown by the arrow A in the figure, the solder is not jetted to the electronic component. The central axes along the transport direction are configured so as not to coincide with each other. As described above, the electronic component can be surely immersed in the at least two solder jet holes (jet streams) regardless of where the jet nozzle in the range facing the substrate to be transported passes. Therefore, the gas can be expelled by the jet flow of the solder jet holes of the row that has passed first, and the joint portion between the board land and the electronic component can be reliably soldered by the jet flow of the solder jet holes of the row that has passed next.

[0009]

【Example】

 FIG. 1 is a top view showing the structure of a jet nozzle which is an embodiment of the present invention. The substrate 4 on which the chips 5 and the lands 6 are mounted is guided by the left and right guide rails 8 and conveyed onto the jet nozzle. The jet nozzle of the present invention is constructed within the range of the guide rail 8 (within the range of the substrate 4 to be jetted).

In the nozzle of this example, a large number of solder jet holes 11, 12 and 13 are arranged in three rows (enclosed by dotted lines in the figure) of solder jet hole groups 1, 2 and 3 in the substrate transport direction. Further, each solder jet hole is provided so that an axis line (shown by a broken line in the figure) passing through an arbitrary point along the substrate transport direction intersects with another solder jet hole. Taking the solder jet holes 12 as an example, the point d in the solder jet holes 12 is the solder jet holes 21 in the second row solder jet hole group 2 and the solder jet holes in the third row solder jet hole group 3. The point e intersects with the solder jet hole 31 in the solder jet hole group 3 in the third row, and the point f intersects with the solder jet hole 22 in the solder jet hole group 2 in the second row. The point g intersects the solder jet holes 22 in the second row solder jet hole group 2 and the solder jet holes 32 in the third row solder jet hole group 3. The intervals between the solder jet holes in each row are equal, and the intervals between the rows are also equal. Further, in this case, the diameters of the solder jet holes are unified within the range of 4 to 5 mm in each row (the jet may not be formed if the diameter exceeds the range of 4 to 5 mm). Also, the size of the solder jet holes may be slightly different within this range for each row.

However, in this example, as described with reference to FIG. 4, the central axis (shown by the solid line) of the solder jet holes in each row is different for each row. By doing so, it is possible to prevent the solder jet holes in each row from being aligned and aligned with each other. In such a nozzle configuration, for example, when the chip 5 mounted on the substrate 4 (shown by a dotted line because it is on the back side of the substrate 4) is conveyed on the line indicated by the arrow A, the chip 5 is ejected in the first row. The gas that has passed through the solder jet holes of hole group 1 is expelled by the jet pressure at this time at the junction between chip 5 and land 6 of the substrate (shown by the dotted line because it is on the back side of substrate 4). Then, the chip 5 also passes through the solder jet holes of the solder jet hole group 2 of the second row, and at this time the joint is immersed in the jet stream of this solder jet hole, but the solder jet of the solder jet hole group 1 of the first row Since the gas in the holes is exhausted, the solder does not get wet, and the jet flow at this time ensures that the joint is firmly attached.

When the chip 5 is conveyed on the line indicated by B, the chip 5 does not pass through the solder jet holes of the solder jet hole group 1 of the first row, but the solder jet hole group 2 of the second row and the solder jet hole group 2 of the second row. Since the solder jet holes of the third row solder jet hole group 3 pass through, respectively, gas is released by the solder jet holes of the second row solder jet hole group 2, and the solder of the third row solder jet hole group 3 The jet holes ensure soldering.

Further, when the chips 5 are conveyed on the line indicated by C, the chips 5 pass through the solder jet holes of the first row 1 but not the solder jet holes of the second row 2. However, since the chip 5 passes through the solder jet holes of the next third row 3, gas is released by the solder jet hole group 1 of the first row, and soldering is surely performed by the solder jet hole group 3 of the third row. It's really done.

As described above, in this example, the chip 5 is configured to pass the jets of at least two solder jet holes regardless of where it passes, so that the jet contact probability of the chip 5 is increased. Become. In this example, the dipping time of the chip 5 in the jet is almost the same as when passing through the three rows, that is, all three solder jet holes. Don't worry.

In this example, the solder jet hole group is described as three rows, but if there is no problem with the above-mentioned heat resistance, it may be four rows or more, and the row shapes may not be arranged. Further, although only the chip has been described in this example, it is needless to say that the present invention can be applied to various electronic components such as a transistor without being limited to this.

[0016]

【effect】

 As described above, according to the present invention, it is possible to improve the soldering quality by increasing the contact probability of the jet flow with the electronic component and eliminating the soldering failure.

[Brief description of drawings]

FIG. 1 is a top view showing the structure of a jet nozzle according to an embodiment of the present invention.

FIG. 2 is a simplified diagram showing the structure of a conventional solder bath.

FIG. 3 is a top view showing a conventional jet nozzle 75.

FIG. 4 is a top view showing the structure of a special jet nozzle.

[Explanation of symbols]

 1 ... First row solder jet hole group 2 ... Second row solder jet hole group 3 ... Third row solder jet hole group

Claims (1)

[Scope of utility model registration request] 1. A structure of a jet nozzle of a solder bath, in which solder is jetted from a large number of solder jet holes to an electronic component on a substrate to be transported, each solder jet in a range facing the substrate to be transported. An axis along the carrying direction of the substrate passing through any point in the hole intersects with at least one or more other solder jet holes, and a central axis of each solder jet hole along the carrying direction of the substrate, A structure of a jet nozzle of a solder bath, which is configured so as not to coincide with each other.