JPH05161964A - Device for coating flux - Google Patents

Abstract

PURPOSE:To constantly make the air pressure jetted from the air nozzles and to uniformly and high precisely coat the surface to be coated with the prescribed film pressure by arranging air nozzles in a line to the axial direction of the peripheral surface of the outer tube body and stagnating the feeding air of high pressure in the outer tube body through the inner tube body. CONSTITUTION:The air of high pressure carried from an air feeding device to an air tank 21 is flowed in the inside of outer tube air tank 28 having the prescribed capacity from the blow-off nozzle 30 through an inner tube feeding tube 24, and once stagnate here. Therefore, the air pressure jetted from the air nozzles 32 set at the peripheral surface of the outer air tank 28 is made constant by constantly keeping the air pressure of the neighborhood of inner circumference of the outer tube air tank 28 from the air flow due to the feeding pressure of high pressure air of the jetting pressure from the jetting hole 30 of the inner tube air feeding tube 24, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux applicator, and more particularly to a flux applicator for applying a flux to a coated surface of a printed circuit board in a uniform thickness.

[0002]

2. Description of the Related Art In order to attach various electronic components to a printed circuit board by soldering, the soldering work should be carried out effectively and accurately, and at the same time, the erroneous judgment rate of the in-circuit test performed after the soldering should be reduced. Prior to the above, it is necessary to uniformly apply the flux to the back surface of the printed board with a predetermined film thickness. A coating device for uniformly coating the flux is disclosed in, for example, Japanese Patent Laid-Open No.
There is a flux coating device described in Japanese Patent Publication No. 139070.

This conventional flux applicator 50 is
As shown in FIG. 4, the flux drum is rotatably mounted on the flux tank 51, and the lower portion thereof penetrates the mesh drum cylindrical drum 53 and the center of the drum drum 53. The high pressure air pipe 54 is fixed to the tank 51 by a shaft, and the connecting pipe 56 is attached to the high pressure air pipe 54 and has an air nozzle 55 arranged to face the inner surface of the cylindrical drum 53. Then, the cylindrical drum 53 is rotationally driven by the drive motor 58 via the gear 57 and the like,
The flux liquid that has adhered in a film shape to the mesh of the cylindrical drum 53 is conveyed upward. Then, the conveyed flux liquid is applied to the back surface of the printed circuit board 59 passing above the connecting pipe 56 by the air blown from the air nozzle 55.

[0004]

However, the above-mentioned conventional flux applicator 50 has a high-pressure air pipe 60.
Since the air sent from the high pressure air pipe 54 does not have a constant pressure, that is, the pressure is low near the inlet of the high pressure air pipe 54 and increases as the distance from the high pressure air pipe 54 increases, the pressure in the connecting pipe 56 also does not become constant. ,
Therefore, since the pressure of the air ejected from the air nozzle 55 is different, the flux liquid is transferred to the printed circuit board 59.
It becomes difficult to apply a uniform film thickness on the back surface of the with high precision. In such a case, the flux film thickness can be set to be constant by changing the arrangement pitch of the air nozzles 55, but it is easy to change the film thickness to be applied or the shape of the printed circuit board. There was a problem that could not be dealt with.

Therefore, the present invention has been made to solve the above-mentioned problems, in which the pressure of the air ejected from the air nozzle is always kept constant, and the flux is evenly distributed on the coated surface of the printed circuit board at a predetermined film thickness. Also, it is intended to provide a flux applicator that can be easily and accurately applied.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above object, and its gist is to rotatably mount a shaft in a flux tank while partially immersing it in the flux liquid contained in the flux tank. A mesh-shaped cylindrical drum and a flux liquid, which is disposed so as to face the inner surface of the cylindrical drum, is film-like adhered to the mesh of the cylindrical drum and is conveyed upward by the rotation of the cylindrical drum by pressure air to a printed circuit board. In an apparatus for applying a flux, which comprises an air nozzle for spraying on the surface to be coated, an outer cylinder body is provided inside the cylindrical drum, and an inner cylinder body for supplying air from an outlet provided on the outer periphery of the outer cylinder body. The flux coating apparatus includes a double-structured air tank and has a large number of the air nozzles arranged in a line in the axial direction of the outer peripheral surface of the outer cylindrical body.

[0007]

In the flux coating apparatus of the present invention, the high-pressure air sent from the air supply apparatus to the air tank flows from the outlet of the inner cylinder into the outer cylinder having a predetermined capacity. Stay once. Therefore, the air flow due to the supply pressure of the high-pressure air and the injection pressure from the blowout port of the inner cylinder is relaxed in the space inside the outer cylinder, and the air pressure near the inner circumference of the outer cylinder is kept constant to keep the outer circumference of the outer cylinder. The pressure of the air ejected from the air nozzle provided on the surface is made constant.

[0008]

An embodiment of the present invention will now be described in more detail with reference to the accompanying drawings.

The flux coating apparatus 10 of this embodiment is
It is used by incorporating it into the coating system 50 shown in FIG.
That is, the coating system 50 includes a coating device 10 and a carrier chain 12 arranged above the coating device 10 and moving along a conveyor rare rail 11 to apply a printed circuit board to which flux is to be applied, to an air nozzle of the coating device 10. A transport device 14 for passing in the X direction above the opening 13,
Further, a primary filter device 15 arranged above this
And a secondary filter 16 and a housing 17 that covers them. Reference numeral 18 is a duct for ventilating the inside of the housing 17.

As shown in the horizontal sectional view of FIG. 2 and the vertical sectional view of FIG.
And a cylindrical drum 20 rotatably mounted in the flux tank 19, and an air tank 21 fixedly arranged inside the cylindrical drum 20.

The flux tank 19 has a lower portion with the flux liquid 2
2 is a box that houses the cylindrical drum 20 and the air tank 21, and has an air nozzle 32, which will be described later, on the upper end surface.
An air nozzle opening 13 is provided at a position opposed to.

The cylindrical drum 20 is composed of a mesh plate, a punch plate, etc., and the size of these meshes or holes is designed so that a flux liquid film is surely formed on them in relation to the flux concentration. Has been done. Then, the cylindrical drum 20 slowly rotates around the inner cylinder air supply pipe 24, which will be described later, as an axis.
It should be noted that this rotation drive is performed by the drive shaft 2 driven by the drive motor 25.
The rotation of 5'is performed via the drive gear 26 and the rotary gear 27 on the outer circumference of the cylindrical drum 20. The lower portion of the cylindrical drum 20 is immersed in the flux liquid 22, and the flux liquid 22 is attached to the mesh of the cylindrical drum 20 in a film shape as the cylindrical drum 20 rotates and is conveyed upward.

On the other hand, the air tank 21 has a double structure consisting of an inner cylinder air supply pipe 24 and an outer cylinder air tank 28. The inner cylinder air supply pipe 24 is axially fixed to a support wall 29 installed in the flux tank 19, serves as the rotating shaft of the cylindrical drum 20 as described above, and has an outer cylinder air tank 28 at both ends on its outer periphery. Fix tightly. In addition, air outlet holes 30 opening downward are formed in the inner cylinder air supply pipe 24 at predetermined intervals in a row in the axial direction, and the outer peripheral surface of the outer cylinder air tank 28 is axially formed in the axial direction. A linear notch 31 having a substantially V-shaped cross-section that does not penetrate the inside is provided, and a large number of air nozzles 32 that penetrate the inside of the outer cylinder air tank 28 are provided along the notch 31.

If the flux coating device 10 having such a structure is used, the above-mentioned transfer device 14 (see FIG. 1) is used.
It is possible to apply the flux evenly with a predetermined film thickness to the back surface of the printed circuit board 33 that is conveyed by the reference nozzle) and passes above the air nozzle 29. That is, when the sensor attached to the transfer device 14 detects that the printed circuit board 33 is transferred above the air nozzle 29, the air is supplied from the high pressure air supply pipe 60 to the air tank 21.
The air is blown from the air nozzle 32 and is blown from the air nozzle 32 to spray the flux liquid deposited on the mesh of the cylindrical drum 20 in a film shape onto the back surface of the printed board 33 through the air nozzle opening 23. Here, the high-pressure air is fed into the outer cylinder air tank 28 of the air tank 21 through the inner cylinder air supply pipe 24 and the air outlet holes 30 below the inner cylinder air supply pipe 24. Therefore, the high pressure air is supplied to the outer cylinder air tank 28 having a large capacity. The air flow generated by the air supply pressure and the injection pressure from the air outlet 30 is relaxed, and the air pressure near the air nozzle 32 is kept constant without changing in the axial direction of the air tank 21, so that the air is blown from the air nozzle 32. The air pressure is also constant, and as a result, the flux is applied to the back surface of the printed circuit board 33 with a uniform thickness. Then, when the printed circuit board 33 has finished passing above the air nozzle 29, it is sensed by the sensor again, the air supply is stopped, and the flux application is completed.

In this embodiment, the air outlet holes 30 of the inner cylinder air supply pipe 24 are opened downward and are arranged in rows at a predetermined interval. The direction of the opening and the like are not limited to this as long as the atmospheric pressure near the air nozzle 32 can be kept constant.

Further, the flux coating apparatus of the present invention can be applied to various coating techniques.

[0017]

As described above, the flux applicator of the present invention is provided with an air tank having a double structure consisting of an outer cylinder and an inner cylinder inside the cylindrical drum, and the outer peripheral surface of the outer cylinder. Air nozzles are arranged in rows in the axial direction, and high-pressure air is fed and retained in the outer cylinder via the inner cylinder, so the pressure of the air ejected from the air nozzles is kept constant near the inner circumference of the outer cylinder. By keeping constant, the flux can be applied to the surface to be coated of the printed circuit board uniformly at a predetermined film pressure and easily with high accuracy.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a coating system using a flux coating apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an embodiment of the flux coating apparatus of the present invention.

FIG. 3 is a vertical cross-sectional view showing one embodiment of the flux coating apparatus of the present invention.

FIG. 4 is a vertical sectional view showing an example of a conventional flux coating apparatus.

[Explanation of symbols]

 10 Coating Device 20 Cylindrical Drum 21 Air Tank 22 Flux Liquid 24 Inner Cylinder Air Supply Pipe 28 Outer Cylinder Air Tank 32 Air Nozzle 33 Printed Circuit Board

Claims (1)

[Claims] 1. A mesh-shaped cylindrical drum which is partially immersed in a flux liquid in a flux tank and is rotatably mounted on the rotating drum. The cylindrical drum is disposed so as to face an inner surface of the cylindrical drum, and is formed into a film on the cylindrical drum. In a flux coating device including an air nozzle that blows the adhered flux onto a surface to be coated of a printed circuit board, inside the cylindrical drum, an outer cylinder body and an inner cylinder body that supplies air to the outer cylinder body are provided. A flux applicator comprising a double-structured air tank, wherein the air nozzles are arranged in a row in the axial direction of the outer peripheral surface of the outer cylindrical body.