JP2017098313A - Anti-warp fitting and dip soldering machine using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an anti-warp fitting and a dip soldering machine capable of achieving high quality soldering, by suppressing occurrence of red eyes in the vicinity of the anti-warp fitting.SOLUTION: An anti-warp fitting for suppressing warpage of a printed board to be soldered has a structure not obstructing the flowability of molten solder, at a part facing the soldering surface of the printed board to be soldered, or has a structure formed in tabular form, and suppressing harmful effect due to surface tension of the molten solder on the principal surface thereof. A dip soldering machine uses the same, and high quality soldering can be achieved by suppressing occurrence of red eyes in the vicinity of the anti-warp fitting.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a dip soldering apparatus for joining a copper foil portion for connecting an electronic component on a printed circuit board that requires dip soldering and a lead terminal of the electronic component mounted on the printed circuit board with solder in a molten solder bath, and The present invention relates to a warp stopper that suppresses warping of a printed board.

  Conventionally, for soldering a printed circuit board on which an electronic component is mounted, a production method is known in which an electronic component lead terminal and a printed circuit board are soldered using a dip soldering apparatus having excellent mass productivity (for example, Patent Document 1). reference).

  FIG. 5 is a side sectional view showing an internal configuration of a conventional dip soldering apparatus. The configuration and operation will be described below. The printed circuit board P on which electronic components are mounted is placed on the transport rail of the dip soldering apparatus from the printed circuit board carry-in port 101, and the inside of the dip soldering apparatus is automatically moved in the dip soldering apparatus 102 by the arrow X In this order, a flux application process 103, a preheating process 104 (flux activation), a soldering process 105 (bonding the land portion of the printed circuit board and the electronic component terminal section), and a printed circuit board cooling process 106 are sequentially performed. After the process is completed, the printed circuit board P is unloaded from the printed circuit board unloading port 107.

  In the soldering process 105, the solder 108 is vigorously jetted to the soldering place by the primary solder jet port 110 installed in the solder bath 109 in which the solder 108 melted at 255 ± 5 ° C. is placed. At the secondary solder jet port 111, the solder 108 that has been coarsely adhered in the previous step is removed by solder flow of the soft wave at a bridge portion or a portion where the copper foil surface is not exposed. In the solder bath 109 of such a dip soldering apparatus, as shown in FIG. 6, a motor as a stirring device is used to keep the temperature of the molten solder 108 inside the solder bath 109 uniform and a stable metal composition. 114 is provided.

  In addition, depending on the size, thickness, and material of the printed circuit board P, the printed circuit board P may be warped due to heat from the solder bath 109. In order to suppress this warpage, the transporting rail of the printed circuit board transporting conveyor 102 is used. A flat-plate-shaped warp-fixing metal 112 as shown in FIG.

JP 2011-177773 A

  As described above, the material of the printed circuit board P conveyed by the dip solder bath apparatus exceeds the glass transition point (Tg) of the printed circuit board P at the molten solder temperature in the solder tank 109, and the printed circuit board P is warped. There is a problem to do. As a countermeasure, the above-described warp stopper 112 is installed to suppress warping of the printed circuit board P due to heat from the solder bath 109.

However, in such a conventional warp stopper and a dip soldering apparatus using the same, the warp stopper 112 is soaked in the solder bath 109, and therefore, when the printed circuit board P and the electronic component are joined. When the printed circuit board P is immersed in the solder 108 in the solder bath 109, there is a problem that the solder 108 does not adhere to the electronic component terminals and land portions in the vicinity of the warp stopper 112.

  That is, the conventional anti-warp metal fitting 112 has a simple flat plate shape as shown in FIG. 7, and therefore the anti-warp metal fitting 112 and the printed circuit board P in the solder tank 109 and the molten solder 108 are in a state. Is analyzed, the contact portion between the warp stopper 112 and the printed circuit board P has a wide gap S where the solder 108 melted by the surface tension of the solder 108 does not touch the printed circuit board P (FIG. 4 ( c)). This causes a decrease in soldering quality such as generation of red eyes.

  In order to solve such a problem, the present invention reduces defects such as red eyes that occur when soldering between the electronic component terminal mounted on the printed circuit board and the copper foil portion of the printed circuit board, and during dip soldering. It is an object of the present invention to provide a warp stopper and a dip soldering apparatus using the same.

  In order to achieve the above-mentioned object, the warp fixing metal fitting and the dip soldering apparatus using the same according to the present invention have a structure that does not block the fluidity of the melted solder at the portion facing the soldering surface of the printed circuit board to be soldered. An anti-warping metal fitting for suppressing warpage of a printed circuit board to be soldered, characterized in that it has a structure that has a structure that suppresses adverse effects due to the surface tension of solder melted on its main surface, or has a plate shape, and this It is a dip soldering device using

  As a result, while maintaining the original function of suppressing warping of the printed circuit board due to heat from the solder bath, the printed circuit board and the melted solder can be surely brought into contact with each other, or the adverse effects of surface tension can be reduced. As a result, the melted solder in the vicinity of the contact between the warp stopper and the printed board can be reliably attached to the printed board, so that the occurrence of red eyes in the vicinity of the warp stopper can be suppressed.

  According to the warp fitting and the dip soldering apparatus using the same according to the present invention, high-quality soldering can be realized by suppressing the occurrence of red eyes near the warp fitting, and the management man-hour is greatly reduced in terms of management. It becomes possible. Furthermore, by improving the quality of the soldered printed circuit board, the visual inspection after dip soldering and the number of correction personnel using soldering iron can be greatly reduced, and at the same time, the occurrence of secondary defects due to manual solder correction is suppressed. It becomes possible to realize a high-quality product with excellent productivity and cost.

Sectional side view which shows the internal structure of the dip soldering apparatus in Embodiment 1 of this invention The top view which shows the internal structure of the solder tank of the dip soldering apparatus in Embodiment 1 of this invention The perspective view of the curvature stop metal fitting in Embodiment 1 of this invention Explanatory drawing which shows the state of the curvature metal fitting, a printed circuit board, and the melted solder in the solder tank of the dip soldering apparatus in Embodiment 1 of this invention. Side sectional view showing the internal structure of a conventional dip soldering device Top view showing the internal structure of the solder bath of a conventional dip soldering device Perspective view of conventional warp stopper

  The warp fitting of the first invention has a structure that does not block the fluidity of the melted solder at the portion facing the soldering surface of the printed circuit board to be soldered, thereby preventing red eyes near the warp fitting. By suppressing, high-quality soldering can be realized, and management man-hours can be greatly reduced in terms of management. Furthermore, by improving the quality of the soldered printed circuit board, the visual inspection after dip soldering and the number of correction personnel using soldering iron can be greatly reduced, and at the same time, the occurrence of secondary defects due to manual solder correction is suppressed. It becomes possible to realize a high-quality product with excellent productivity and cost.

  A warp stopper according to a second aspect of the present invention is the structure according to the first aspect, wherein a plurality of recesses are provided in a portion facing the soldering surface of the printed circuit board so that the fluidity is not obstructed by a relatively simple configuration. It is possible to suppress the occurrence of red eyes near the warp stopper.

  The warp stop fitting of the third invention is formed in a plate shape and has a structure that suppresses the adverse effect due to the surface tension of the melted solder on its main surface, thereby suppressing the occurrence of red eyes near the warp stop fitting. Thus, high-quality soldering can be realized, and management man-hours can be greatly reduced in terms of management. Furthermore, by improving the quality of the soldered printed circuit board, the visual inspection after dip soldering and the number of correction personnel using soldering iron can be greatly reduced, and at the same time, the occurrence of secondary defects due to manual solder correction is suppressed. It becomes possible to realize a high-quality product with excellent productivity and cost.

  According to the fourth aspect of the present invention, in the third aspect of the present invention, since the shape viewed from the thickness direction is formed in a reverse convex shape, the configuration for suppressing the adverse effect due to the surface tension of the melted solder is simplified. It can be realized by the shape, and it is possible to suppress the occurrence of red eyes near the warp fitting.

  According to a fifth aspect of the present invention, in the third invention, the main surface is formed in a concavo-convex shape, so that adverse effects due to the surface tension of the melted solder can be suppressed from the lower portion of the anti-warping metal fitting. It is possible to suppress the occurrence of red eyes near the warp fitting.

  A dip soldering apparatus according to a sixth aspect of the present invention is provided in a solder bath for storing solder melted by heating means, a conveyor for transporting a printed circuit board on which electronic components are mounted, and stored in the solder bath. By providing at least one solder jet port for ejecting the melted solder toward the printed circuit board and the warp-preventing metal fitting according to any one of the first to fifth inventions, By suppressing the occurrence of red eyes, high-quality soldering can be realized, and management man-hours can be greatly reduced in terms of management. Furthermore, by improving the quality of the soldered printed circuit board, the visual inspection after dip soldering and the number of correction personnel using soldering iron can be greatly reduced, and at the same time, the occurrence of secondary defects due to manual solder correction is suppressed. It becomes possible to realize a high-quality product with excellent productivity and cost.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 is a side sectional view showing an outline of the structure inside a dip soldering apparatus according to Embodiment 1 of the present invention. In FIG. 1, a printed circuit board carry-in port 1 provided at the left end of the dip soldering apparatus is an entrance for a printed circuit board P on which components are mounted. The printed circuit board P transported from the printed circuit board carry-in port 1 is transported on the printed circuit board transport conveyor 2 (conveyor) and transported in the dip soldering apparatus in the direction of the arrow X.

  The printed circuit board P transported from the printed circuit board carry-in port 1 is applied with flux in order to remove the surface contamination by the flux application unit 3 and improve the wettability of the solder. Then, after the electronic component is preheated to about 100 ° C. to 120 ° C. in the preheating unit 4, the electronic component is installed facing the opening 5 opened upward in the solder tank 9 in which the melted solder 8 is put. The electronic component lead terminal and the copper foil portion of the printed circuit board P are soldered by the solder 8 of about 250 ° C. to 260 ° C. ejected from the primary solder jet port 10 and the secondary solder jet port 11. And it passes through the printed circuit board cooling part 6, and is carried out from the printed circuit board carrying-out port 7 provided in the right end part of the dip soldering apparatus.

  The speed of the printed circuit board conveyor 2 is such that the best soldering quality can be obtained by setting the contact time of the printed circuit board P and the solder 8 at the primary solder jet port 10 and the secondary solder jet port 11 to 3 to 5 seconds. 1.0 m / min to 1.7 m / min.

  FIG. 2 is a top view showing the configuration in the solder bath of the dip soldering apparatus according to Embodiment 1 of the present invention. The solder tank 9 is formed in a substantially rectangular parallelepiped box shape having an opening 5 opened upward, and is internally attached with heating means attached in contact with or close to the side and bottom surfaces of the solder tank 9, respectively. 300 kg to 500 kg of solder 8 melted by 13 is stored in a state of being maintained at a constant temperature at a high temperature of 250 ° C. to 255 ° C.

  A primary solder jet port 10 and a secondary solder jet port 11 for jetting the molten solder 8 stored in the solder bath 9 are arranged facing the opening 5 of the solder bath 9, and these solders are provided. By the jet of the molten solder 8 from the jet ports 10 and 11, the copper foil portion of the printed circuit board P and the lead terminal of the electronic component are connected by soldering.

  In order to keep the temperature of the melted solder 8 inside the solder bath 9 uniform and to keep a stable metal composition, the melted solder 8 is always stirred by the motor 14 provided as a stirring device, and the solder 8 is put into the solder bath 9. It is flowing in. In addition, as a stirring apparatus of the solder 8, it can also be set as the structure by an electromagnetic system other than a motor.

  The solder jets 10 and 11 installed in the solder bath 9 control the jet flow from the lower part to control the solder jet from the nozzle. At the primary solder jet port 10, the solder 8 is ejected vigorously and rough soldering is performed. At this time, since the solder 8 has a viscosity, a solder bridge in which the electronic component terminals that should not be connected may be soldered due to surface tension. In addition, there may be a problem called red-eye that does not adhere to locations where solder should adhere. Particularly for the through-hole substrate, it is important to stabilize the height of the jet at the primary solder jet port 10 and the jet flow.

  In the secondary solder jet port 11, the solder 8 is ejected more gently than in the primary solder jet port 10, and a portion soldered roughly by the primary solder jet port 10 is soldered by a secondary jet and a gentle solder flow. Finish the affixed part and suppress defects such as solder bridges and red eyes.

In the solder tank 9, in order to suppress warping of the printed circuit board P due to heat from the solder 8 in the solder tank 9, the soldering surface of the printed circuit board P is parallel to the transport rail of the printed circuit board transport conveyor 2. A plate-shaped warp stopper 12 is provided so as to face the vicinity of the center and to be disposed at a substantially right angle to the soldering surface. The warp fitting 12 is detachable with respect to the inside of the solder tank 9, and in the state where it is immersed and mounted in the molten solder 8, the lower surface (copper foil portion of the printed circuit board P on which the upper surface portion 12a is conveyed. It is set so as to be located immediately under the soldering surface). And the curvature metal fitting 12 is installed so that the center part of the printed circuit board P may be supported from the bottom, when the printed circuit board P is conveyed over the solder tank 9 from the preheating part 4 where heat is applied to the printed circuit board P. .

  FIG. 3 is a perspective view showing the structure of the warp stop fitting of the dip soldering apparatus according to Embodiment 1 of the present invention. The thing of three types of shapes shown to Fig.3 (a)-FIG.3 (c) is illustrated. FIG. 4 shows the state of the warp stopper, the printed circuit board, and the molten solder in the solder bath of the dip soldering apparatus according to Embodiment 1 of the present invention. FIG. 4 (a) is a front view. FIG. 4B shows a side view (enlarged view). For comparison, FIG. 4C shows a state viewed from the front in the case of using a conventional warp stopper.

  As shown in FIG. 3, the warp stopper 12 in the present embodiment reliably attaches the molten solder 8 in the vicinity of the contact between the warp stopper 12 and the printed board P to the copper foil portion of the printed board P, or The structure is characterized in that the surface tension of the melted solder 8 generated between the warp stopper 12 and the printed circuit board P is reduced.

  3 (a) to 3 (c) all have a plurality of recesses 12b on the upper surface part 12a, and the plurality of recesses 12b are transported in the direction of the printed circuit board P (in the direction of the arrow X). Are arranged side by side, and the longitudinal direction (the direction of conveyance of the printed circuit board P) is uneven, so that when the printed circuit board P is warped by heat, it is conveyed when the warpage prevention metal fitting 12 suppresses the warpage. A portion (a plurality of recesses 12b) where the printed printed circuit board P and the warp stopper 12 are not in contact is provided so that the printed circuit board P and the melted solder 8 are reliably in contact with each other.

  In the conventional configuration, as shown in FIG. 4C, the area where the solder 8 is not sufficiently spread (gap S) is widened near the upper surface of the printed circuit board P and the warp fitting 12 due to the surface tension of the molten solder 8. The melted solder 8 could not be completely attached to the printed circuit board P.

  On the other hand, according to the configuration of the present invention, since the upper surface portion 12a of the warp stopper 12 has a plurality of recesses 12b, as shown in FIGS. 4 (a) and 4 (b), the printed board P and the warp stopper The range (gap S) in which the solder 8 in the vicinity of the upper surface portion 12a of 12 does not spread can be reduced, and the molten solder 8 can be reliably attached to the printed circuit board P. Therefore, according to the warp stop fitting of the present invention and the dip soldering apparatus using the same, it is possible to attach the melted solder 8 also to the vicinity of the warp stop fitting to which the melted solder has not been attached. Generation | occurrence | production of soldering defects, such as generation | occurrence | production of the red eye of the fastener 12 vicinity, can be suppressed, and soldering quality can be improved.

  Moreover, as shown in FIG.3 (b), it is made into the front view reverse convex shape seen from the thickness direction, or as shown in FIG.3 (c), several recessed part 12c is arranged in both sides of the substantially plane part which is a main surface. By arranging and making it uneven, the shape is less affected by the surface tension, and the area (gap S) where the solder 8 due to the surface tension in the vicinity of the printed circuit board P and the upper surface portion 12a of the warp stopper 12 is not spread is reduced. By doing so, the same effect can be obtained.

  Further, by using the configuration of FIG. 3 (a) in combination with the configuration of FIG. 3 (b) or FIG. 3 (c), it is possible to suppress the occurrence of soldering defects such as the occurrence of red eyes in the vicinity of the warp stopper 12. The effect of improving the soldering quality can be further enhanced.

  In addition, the configuration of the concavo-convex shape of the flat portion of the warp fitting 12 of the present embodiment is not limited to a configuration in which a plurality of groove-shaped recesses 12c as shown in FIG. A plurality of recesses that are independent from each other may be arranged in a straight line or in a lattice shape, and the same effect can be obtained.

  As described above, the warp fitting according to the present invention and the dip soldering apparatus using the same can achieve high-quality soldering when soldering a printed circuit board on which electronic components are mounted. It is useful as a dip soldering apparatus or the like that conveys a printed board on which components are mounted and conveys molten solder from a solder jet port to join an electronic component terminal and a printed board copper foil portion.

1 Printed Circuit Board Carriage 2 Printed Circuit Board Conveyor (Conveyor)
DESCRIPTION OF SYMBOLS 3 Flux application part 4 Preheating part 5 Opening part 6 Printed circuit board cooling part 7 Printed circuit board carry-out port 8 Solder 9 Solder tank 10 Primary solder jet port 11 Secondary solder jet port 12 Warpage prevention metal fitting 12a Upper surface part 12b, 12c Recessed part 13 Heating means 14 Motor

Claims (6)

A warpage-preventing metal fitting for suppressing warpage of a printed circuit board to be soldered, characterized by having a structure that does not block the fluidity of molten solder at a portion facing a soldering surface of the printed circuit board to be soldered. The warp stop fitting according to claim 1, wherein a plurality of recesses are provided in a portion facing the soldering surface of the printed circuit board. A warpage-preventing metal fitting for suppressing warpage of a printed circuit board to be soldered, characterized in that it has a structure which is formed in a plate shape and suppresses adverse effects due to the surface tension of the melted solder on its main surface. The warp fitting according to claim 3, wherein the shape viewed from the thickness direction is formed in a reverse convex shape. The warp stop fitting according to claim 3, wherein the main surface is formed in an uneven shape. A solder bath for storing solder melted by the heating means; a conveyor for transporting a printed circuit board on which electronic components are mounted; and the molten solder provided in the solder bath and stored in the solder bath. A dip soldering device comprising: at least one solder jet port that is ejected toward the head and the anti-warping metal fitting according to any one of claims 1 to 5.

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