JP2001009346A - Viscous material coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the component separation and component precipitation of a viscous material and improve a coating performance, by arranging a scraping means for the viscous material at a delivery opening which communicates with a storage chamber of the viscous material in a device body and faces a coating surface, and arranging a stirring means for the viscous material in a passage between the storage chamber and the discharge opening. SOLUTION: When coating operation is carried out, a direct-acting unit 8 is moved by a control part 10 through a driving part 9 and a chamber 5 connected to the direct-acting unit 8 is moved while a squeegee 1 comes into contact with a mask 3 which is a coating surface. A viscous material 2 in the chamber 5 is pressured by a pressure means 6 to fill the opening part of the mask 3. When production is stopped, the chamber 5 is reciprocatingly moved within a prescribed range excluding the opening part of the mask 3. The reciprocating movement scrapes the viscous material 2 separated in the vicinity of a discharge opening 20 of the chamber 5, and the rotation of a stirring shaft stirs the viscous material 2 in the chamber 5, surely preventing the component separation and the component precipitation respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for applying a viscous material, such as a solder paste or a conductive paste, from which a composition component is easily separated.

[0002]

2. Description of the Related Art A conventional viscous material coating apparatus will be described with reference to a schematic diagram of FIG. 2. Description of the Related Art Conventionally, in the field of surface mounting technology for mounting an electronic component on a substrate, a squeegee method as shown in FIGS. Has been used. In the squeegee method, a squeegee 1 in which urethane rubber, a metal plate or the like is attached so as to be in contact with the mask 3 in parallel with the mask 3 is used as the squeegee 1 and a viscous material 2 such as a solder paste or a conductive paste is supplied in the traveling direction. The material is advanced while pressing the material against the surface of the mask 3 by the squeegee 1 (FIG. 5A). An opening 3a is provided at a predetermined location of the mask 3, and the opening 3a of the mask 3 is filled with the viscous material 2 (FIG. 5B). Thereafter, when the squeegee 1 passes through the opening 3a of the mask 3, the excess viscous material 2
After the squeegee 1 has passed through all the openings 3a, the printed circuit board 4 disposed on the lower surface of the mask 3 is separated from the mask 3 (FIG. 5 (c)). In this method, the viscous material 2 filled in the opening 3a is transferred and applied onto the printed circuit board 4.

In the squeegee method, the filling pressure required for filling the mask opening with a viscous material is changed by changing factors such as the moving speed of the squeegee and the mounting angle of the squeegee. It is generally known that filling pressure increases as the mounting angle of the squeegee decreases. However, in practice, when the mounting angle of the squeegee is reduced, the scraping of the surplus viscous material becomes insufficient and is not practical. Therefore, the change width of the mounting angle is necessarily limited, and the filling pressure within this practical mounting angle range hardly changes, and only a limited value can be obtained.

[0006] According to the measurement results shown in FIG. 6, it can be seen that the peak value of the filling pressure of the measured value is constant without change even when the squeegee mounting angle is changed. In general, in the case of a filling operation, when the area of the opening of the mask is reduced, it becomes difficult to fill the opening with the viscous material, and a higher filling pressure is required. In this case, the filling pressure by the above-described squeegee method may not be able to sufficiently fill the entire mask opening with the viscous material, and there is a limit minimum area of the opening area that can be filled.

Therefore, in order to make up for the disadvantage, a chamber type viscous material coating method capable of forcibly applying a filling force as shown in FIG. 7 has been used in recent years. As shown in FIG. 7, the viscous material 2 filled in the chamber 5 is formed between the pair of squeegees 1 provided in the chamber 5 by forcibly applying pressure by the pressing means 6. A force for pushing out the viscous material 2 from the discharge port acts to forcibly fill the opening 3a on the mask 3 with the viscous material 2. That is, the pressing force forcibly applied to the viscous material 2 is:
Since the filling pressure of the viscous material 2 into the opening 3a is obtained, the filling pressure can be increased as needed depending on the area of the opening 3a.

When using these conventional coating methods (squeegee method and chamber method), if the coating operation is interrupted, it is necessary to stand by at a standby position without an opening on the mask and to stand by until the coating operation is resumed. become.

[0007]

However, in the above-described conventional viscous material application method using the chamber method, the viscous material stored inside has a separability, and the chamber is left in a state filled with the viscous material. In this case, separation occurs in the chamber, and depending on the material, if the material is used for a long time, there is a possibility that components may precipitate on the mask surface near the mask at the discharge port of the chamber. This is because even when the chamber is moving during the application of the viscous material, in the case of the chamber method, only a small amount of the viscous material near the discharge port, that is, near the mask, flows due to friction from the mask, and the flow in the chamber is reduced. This is because the entire viscous material is in an environment where it is difficult to flow. That is,
The component separation of the viscous material having separability proceeds even in the state where the coating operation is continuously performed, and when the coating operation is stopped, the component separation particularly in the vicinity of the discharge port of the chamber proceeds, Depending on the material, the components may have precipitated.

On the other hand, in the above-mentioned squeegee coating method, as shown in FIG. 8, during continuous coating operation, the operation itself is a function of stirring the viscous material 2, and the whole operation is always performed. It can be said that this is the same as when the stirring is performed. However, even in this case, when the coating operation is stopped and left for a long time, the mask 3 in the viscous material 2
There is a possibility that component separation has occurred near the surface, and in some cases, component precipitation has occurred.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. Even when a coating operation is performed using such a viscous material having component separation properties, component separation and precipitation of components can be achieved. It is an object of the present invention to improve the workability of applying a viscous material having separability and improve the quality by preventing the separation.

[0010]

According to the present invention, there is provided a viscous material coating apparatus according to the present invention, comprising: an apparatus main body having a storage chamber for storing a viscous material; The discharge port facing the surface has a means for scraping the viscous material, and a means for stirring the viscous material in the storage chamber and in the path from the storage chamber to the discharge port.

As a scraping means, a pair of squeegee portions disposed on both sides in the front-rear direction of the discharge port and facing the application surface and in contact with the application surface, and a drive for reciprocating the squeegee portion in a straight line while in contact with the application surface. It is preferable to use one composed of the first and second parts.

The scraping means is disposed on both sides in the front-rear direction of the discharge port, and is disposed between the pair of squeegee portions facing the coating surface and in contact with the coating surface, and between the squeegee portions so as to contact the coating surface. It is preferable to use a plate composed of a plate and a drive unit for performing an operation of scraping the viscous material in the entire contact area between the discharge port and the coating surface in parallel with the coating surface.

Further, it is preferable that the above-mentioned viscous material coating apparatus be provided with a pressurizing means for applying pressure to the viscous material in the storage chamber.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A viscous material coating apparatus according to an embodiment of the present invention will be described below.

FIGS. 1A and 1B show the entire structure. A pair of squeegees 1 and 1 are attached to the chamber (apparatus main body) 5 on both sides in the direction in which the chamber 5 moves linearly, that is, in the front-rear direction.
An ejection port 20 facing the application surface is formed therebetween. The storage chamber inside the chamber 5 is filled with the viscous material 2 without gaps. The viscous material 2 pressurized by the pressurizing means 6 disposed in the storage chamber is supplied from the discharge port 20 to the coating surface of the mask 3.

The pressurizing means 6 is constituted by a tube 6a made of nylon or rubber whose volume increases or decreases when compressed air is supplied or discharged, and the tube 6a is pressurized and controlled through connectors 6b and 6b. It communicates with the part 7.

The chamber 5 is connected to a linear motion unit 8. The operation of the linear motion unit 8 such as a moving speed and a moving range is controlled by a drive unit 9 and a drive control unit 10.

Further, plate-shaped stirring shafts (stirring means) 11 for stirring the viscous material 2 are provided on both sides of the chamber 5 at positions below the pressurizing means 6 in the storage chamber. The bearings 11a are rotatably supported by the bearings 11a. A pulley 11b is fixed to one end of the stirring shaft 11, and the stirring shaft 11 is driven by a motor (not shown).
b is driven to rotate.

Next, the operation will be described. First, in a normal coating operation, the chamber 5 connected thereto is moved in parallel with the squeegee 1 in contact with the mask 3, which is the coating surface, by the linear motion unit 8 whose operation is controlled by the drive unit 9. At this time, the viscous material 2 inside the chamber 5 is pressurized by the pressurizing means 6. Thus, when the chamber 5 moves over the mask 3 and approaches the opening of the mask 3, the internal pressure of the pressurized viscous material 2 inside the chamber 5 becomes the filling pressure to the opening of the mask 3 and fills. Is done. This operation is repeated in the usual work of applying a viscous material to a printed board, but when the production is stopped, the chamber 5 stands by at a position where there is no opening on the mask 3.

At this time, if the viscous material 2 inside the chamber 5 has a separability if the same material on the mask 3 is stopped for a long time, there is a possibility that component separation or component precipitation may occur. is there.

Therefore, while the production is stopped, the chamber 5 is moved to a position where there is no opening on the mask 3.
By reciprocating a given distance reciprocally and linearly by an operation control of the drive unit 9 via the linear motion unit 8 (this operation may be referred to as a swing operation), the chamber 5 is separated into the vicinity of the discharge port 20 of the chamber 5. Scraping the viscous material 2,
Further, the rotation of the stirring shaft 11 causes the chamber 5
The viscous material 2 inside is stirred to prevent component separation or precipitation of components.

FIGS. 2A to 2C show the swing stirring operation using the above-described chamber configuration. The chamber 5
During production standby, the squeegees 1 and 1 are moved in the printing direction by the distance of 10 mm within the range where there is no opening on the mask 3 and then moved again by 10 mm in the opposite direction and returned. The moving speed of the chamber 5 is 5 mm / sec. By this operation, the viscous material 2 separated in the vicinity of the discharge port 20 of the chamber 5 is scraped off, and the viscous material 2 inside the chamber 5 is rotated by rotating the stirring shaft 11 at a constant speed.
Is stirred. This operation is repeatedly performed during production standby.

The graph shown in FIG. 3 is the result of examining the change in viscosity of the internal viscous material in the following two conditions of the chamber standby state when the production is assumed to be stopped for 2 hours. The viscous material in this case is about 90% by weight of copper powder in the component.
It is a conductive paste containing. As a material characteristic, the copper powder kneaded in the solvent is easily separated by leaving at room temperature, and if left for a long time (about 30 minutes), the solvent and the copper powder are partially separated completely and the copper powder is separated. Powder precipitation occurs.

<Condition 1> A state in which the chamber stands still for 2 hours within a range where there is no opening on the mask <
Condition 2> From the measurement result of the state in which the chamber is kept waiting while swinging the chamber with a stroke longer than the interval between the two squeegees attached to the chamber, the chamber discharge port It can be seen that the viscosity of the viscous material existing in the vicinity of contacting the mask is higher than the initial viscosity. On the other hand, when the chamber is continuously oscillated as in condition 2, even after 2 hours of standing, there is no increase in the viscosity of the viscous material near the discharge port at the tip of the chamber with respect to the initial viscosity. This can be said to have the effect of preventing the separation of the components of the viscous material and the precipitation of the components.

As shown in FIG. 4, between two opposing squeegees 1, 1 installed in a chamber 5,
Plate 1 having a surface in contact with mask 3 which is a coating surface
Place 3. This plate 13 is used for two squeegees 1,
By reciprocating between the two, the operation of scraping the components of the viscous material 2 that separates and precipitates on the upper surface of the mask 3 at the discharge port of the chamber 5 is performed. If this condition is condition 3,
As for the viscosity change measurement result of the viscous material 2 after being left for 2 hours under the operation of the condition 3, the viscosity of the viscous material 2 at the chamber outlet does not change from the initial viscosity, as in the case of the condition 2 described above. It can be said that there is an effect of separating components and preventing precipitation of components.

[0026]

According to the present invention, in the application of a viscous material having separability, it is possible to prevent the separation of the components of the viscous material and the precipitation of the components even when production is interrupted for a long time. Therefore, it is possible to always obtain the coating workability with stable quality.

[Brief description of the drawings]

FIGS. 1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a transverse sectional view, and FIG.

FIG. 2 shows the operation of the first embodiment of the present invention (a).
It is explanatory drawing shown to (b) and (c).

FIG. 3 is a comparative diagram comparing the effect of the first embodiment of the present invention with a conventional example.

FIG. 4 is a transverse sectional view showing a second embodiment of the present invention.

FIGS. 5A to 5C are side views showing the operation of a conventional example.

FIG. 6 is a graph showing a result of measuring a filling pressure in a conventional example.

FIG. 7 is a side view of an apparatus showing a modification of the conventional example.

FIG. 8 is an operation explanatory diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Squeegee (squeegee part) 2 Viscous material 3 Mask (coating surface) 5 Chamber (apparatus main body) 6 Pressurizing means 9 Drive part 11 Stirring shaft (stirring means) 13 Plate 20 Discharge port

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/12 610 H05K 3/12 610Q 3/34 505 3/34 505D (72) Inventor Toshinori Mimura Osaka 1006 Kadoma Kadoma Matsushita Electric Industrial Co., Ltd. BB72 DD03 FF02 FF04 GG06

Claims (4)

[Claims] 1. An apparatus main body having a storage chamber for storing a viscous material, and a means for scraping the viscous material at a discharge port disposed in communication with the storage chamber and facing an application surface, and A viscous material application device comprising means for agitating a viscous material in a room and in a path from a storage chamber to a discharge port. And a pair of squeegee sections disposed on both sides in the front-rear direction of the discharge port and facing the application surface and in contact with the application surface, and reciprocatingly moving the squeegee portion in contact with the application surface. The viscous material coating device according to claim 1, comprising a driving unit. 3. A scraping means is disposed on both sides in the front-rear direction of the discharge port, a pair of squeegee portions facing the application surface and in contact with the application surface, and disposed between the squeegee portions so as to contact the application surface. 2. The viscous material coating apparatus according to claim 1, further comprising a plate, and a drive unit for performing an operation of scraping the viscous material in the entire contact area between the discharge port and the coating surface in parallel with the coating surface. 4. The viscous material coating apparatus according to claim 1, further comprising a pressurizing means for applying pressure to the viscous material in the storage chamber.