JP4805878B2 - Flux applicator - Google Patents

Description

  The present invention relates to a soldering technique, and more particularly to a flux application tool applied before soldering.

  Along with the recent shift to lead-free soldering, printed circuit boards that have been prefluxed on copper foil have become the mainstream. In such printed circuit boards, prefluxing is performed when reflow and flow soldering processes are performed. Will volatilize. Therefore, the surface of the copper foil relating to through holes for other retrofit components such as connectors and other lands is exposed after the flow / reflow and the oxidation proceeds, so that the wettability of the retrofit components during soldering deteriorates. Therefore, it is the mainstream to apply flux again when soldering retrofit components.

Such flux coating methods currently include a manual brushing method, a dripping method as described in Patent Document 1, and a spraying method as described in Patent Document 2.
JP-A-8-25031 JP-A-11-277223

  In the case of the brush coating method, since it is manual, there is a variation in the amount of flux applied to each operator, and there is a problem in quality stability. Also, especially when applying flux to the terminal protruding to the opposite side of the board through the through hole, such as in the case of a connector with pin terminals protruding in a line, it is necessary to brush from the top of the terminal. There are many problems such as flux not reaching enough and not reaching the inside of the through hole.

  In the case of the dripping method, a droplet of flux is dropped from the end of the pipe, but when the soldering parts become smaller and the amount of flux applied becomes small, the surface tension of the flux causes the tip of the pipe to The phenomenon that the droplets do not fall off frequently occurs, and the application of the flux is interrupted. In other words, in the case of the above-described connector, a flux drop does not fall and a terminal that is not applied comes out, which affects the soldering quality.

  In the case of the spray method, as the distance between other parts and wiring becomes narrower due to the miniaturization of parts, the sprayed flux scatters to other parts that dislike the adhesion of flux. Is difficult.

  As described above, in any of the current systems, there are problems such as application of a stable and appropriate amount of flux and prevention of adhesion to other materials, and a solution is desired. This invention pays attention to this point, and proposes a flux applicator devised so that an appropriate amount of flux can be stably applied and scattering to other parts can also be prevented.

Flux applicator according to the present invention includes two or more side wall portion disposed on both sides of each row of pins which are arranged one or more rows protruding from the through hole (soldering sites), the upper end of the side wall portion And a flux supply hole that passes through the ceiling portion and communicates with the space sandwiched between the side wall portions, and the flux fed into the space from the supply hole It is held in the space by surface tension.

  According to the flux applicator of the present invention, for example, when the side wall portions are arranged on both sides of the soldering site such as a row of pin terminals protruding through the through holes, the side wall portion and the ceiling portion surround the soldering site ( Tunnel) is formed. And if a flux is sent into the space through a supply hole, the said flux will contact and adhere to a soldering site | part directly. Therefore, scattering can be prevented and the flux can be reliably applied to the soldering site.

  That is, instead of dropping the flux as in the dropping method, the flux is supplied into the space and directly touches the soldering site, so even if the flux is small, it adheres to the soldering site without interruption. . In addition, since the flux supplied into the space is held in the space by surface tension, the soldering part that enters the space is in a state of being bumped, and the flux should be applied evenly throughout. Can do. Furthermore, since the flux held in the space is also sucked into the through hole by capillary action, the flux spreads as a whole including the inside of the through hole. Therefore, an appropriate amount can be stably distributed over the entire soldering site as compared with the manual brushing method.

  In addition, the side wall portion set up beside the soldering part prevents the flux from scattering or flowing out of the part other than the part, so that it does not affect other parts as in the spray method.

  A preferred embodiment is illustrated in FIGS.

  The flux applicator of this example shows an example of an optimal shape when soldering the pin terminal of a connector which is a retrofit component. The connector C is mounted on the opposite surface of the printed circuit board PCB, and the pin terminals CP aligned in a row protrude through the through hole TH. The pin terminal CP and the through hole TH are the soldering parts in this example.

  The flux applicator has rectangular parallelepiped side wall portions 1 and 1 disposed on both sides with a pin terminal CP and a through hole TH as soldering portions in between. The side wall portions 1 and 1 are formed higher than the protruding length of the pin terminal CP, and a rectangular parallelepiped ceiling portion 2 is bridged over the upper ends of the side wall portions 1 and 1. Therefore, the flux applicator in the illustrated example has a U-shaped cross section that opens downward, and can be integrally formed with a metal material or a resin material. A flux supply hole 4 that penetrates the ceiling portion 2 and communicates with a space 3 sandwiched between the side wall portions 1 and 1 is formed.

  In other words, the flux applicator of the present embodiment has a straight groove (space 3) formed in the lower surface 1a of the rectangular parallelepiped as an optimal shape for flux application to the pin terminals CP and the through holes TH arranged in a row. A surface other than the lower surface 1a, in the case of this example, is formed with a supply hole 4 penetrating from the upper surface 2a into the groove (space 3) and supplying flux into the groove (space 3).

  In addition, when the pin terminals are arranged in two or more rows, a plurality of grooves (spaces 3) can be formed in parallel (three or more side wall portions 1 are formed). In addition, a rectangular parallelepiped is suitable for a board on which components are mounted at a narrow pitch, but a groove is provided on the bottom surface of a triangular pyramid, or a cylinder is laid and a groove is recessed on its peripheral surface. It is also possible to use other three-dimensional shapes such as those provided. Furthermore, even in the case of a rectangular parallelepiped, an example in which the lower surface 1a (the lower surface of the side wall portion 1) and the upper surface 2a (the upper surface of the ceiling portion) are formed in an arc shape in consideration of the shape of the soldering part is possible.

  For such a flux applicator, the flux sucked out by the pump 11 from the flux container 10 is supplied through the resin tube 12. That is, the tip of the tube 12 is connected to the supply hole 4 of the flux applicator, and an appropriate amount of flux is supplied by the control of the pump 11. Then, the flux applicator is moved along the pin terminal CP which is a soldering site, and the flux is applied from the space 3 into the pin terminal CP and the through hole TH.

  The flux applicator can be used, for example, in the vicinity of a soldering iron of an automatic soldering apparatus, and the flux applicator is applied with flux to the soldering site immediately before soldering with the soldering iron, It is possible to realize an apparatus that automatically executes soldering following flux application (FIG. 1). In such a case, by incorporating a heating means (heater, hot air heater) for heating the flux applicator and controlling the temperature, the heated flux can be supplied, so that the activity of the flux can be improved and preheating before soldering can be performed. And it looks good.

  The flux supplied to the flux applicator is fed into the space 3 through the supply hole 4. In the space 3 having a tunnel shape formed by the side wall portions 1 and 1 and the ceiling portion 2, the fed flux is held by surface tension. When the flux is held in the space 3, the pin terminal CP and the through hole TH entering here are in a bumped state, and in particular, the pin terminal CP is totally immersed in the flux. Accordingly, even when the flux is supplied little by little, it adheres to the soldering site without interruption, and the flux is applied evenly as a whole. Further, the flux held in the space 3 is also sucked into the through hole TH by the capillary phenomenon, and the flux spreads as a whole including the inside of the through hole TH.

  In addition, the side wall portions 1, 1 standing beside the pin terminal CP and the through hole TH prevent the flux from scattering or flowing out to the part other than the soldering portion surrounded by the side wall portions 1, 1.

The figure which shows embodiment of the flux applicator which concerns on this invention incorporated in the soldering iron vicinity. The perspective view of the flux applicator which concerns on this invention. Sectional drawing of the flux applicator which concerns on this invention. The figure explaining the flux supply path | route to the flux applicator which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Side wall part 1a Lower surface 2 Ceiling part 2a Upper surface 3 Space (groove)
4 Supply hole

Claims (3)

And two or more side wall portion disposed on both sides of each row of pins which are arranged one or more rows protruding from the through hole,
A ceiling portion spanning the upper end of the side wall portion;
A flux supply hole that penetrates through the ceiling portion and communicates with a space sandwiched between the side wall portions.
The flux applicator, wherein the flux fed into the space from the supply hole is held in the space by surface tension. A groove having one or more stripes is provided in the lower surface of the rectangular parallelepiped, and a supply hole for supplying flux into the groove penetrating from the upper surface of the rectangular parallelepiped into the groove is formed.
The flux is fed from the supply hole to the groove is held in the groove by surface tension, applying a flux through each column of pins which are arranged one or more rows to protrude from the through holes in each said groove Features a flux applicator. The flux applicator according to claim 1 or 2,
Flux is supplied from the pump through the supply hole while being installed near the soldering iron and heated,
A flux applicator, wherein flux is applied from the space or the groove to pin terminals protruding from the through holes before soldering by the soldering iron and arranged in one or more rows .

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