JPH06234204A - Screen printing device for cream solder - Google Patents

Abstract

PURPOSE:To provide a screen printing device for cream solder, which is capable of transferring the cream solder on a print substrate while kneading the cream solder sufficiently and filling the same into the pattern hole of a mask plate. CONSTITUTION:A squeegee 44, sliding on a mask plate 13, is provided with a cylindrical shape to reserve cream solder 10 in the cylinder and the squeegee 44 is moved into X-direction and/or Y-direction while rotating it into horizontal direction by a rotating motor 41 to transfer the cream solder 10, filled into the pattern hole 14 of the mask plate 13, onto a print substrate 15. According to this method, the squeegee 44 is rotated in the horizontal direction whereby the cream solder 10 is kneaded sufficiently and is filled into the pattern hole 14 of the mask plate 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cream solder screen printing apparatus for applying cream solder to electrodes of a circuit pattern on a printed circuit board.

[0002]

Prior to the surface mounting of electronic parts on a printed circuit board, cream solder is applied to the electrodes of the circuit pattern of the printed circuit board by a screen printing device.

A conventional screen printing device for cream solder is disclosed in, for example, JP-A-3-154809 or JP-A-4-10.
No. 7147, a printed circuit board is arranged below a mask plate of a screen mask having a pattern hole, and a squeegee is slid on the mask plate to form a circuit pattern of the printed circuit board through the pattern hole. It is designed to apply cream solder to the electrodes.

FIG. 4, FIG. 5, and FIG. 6 are a side view, a front view, and a plan view of a main part during application of the cream solder by the conventional screen printing apparatus for cream solder. A printed circuit board 2 is arranged below the mask plate 1. 3 is a pattern hole formed in the mask plate 1 and 4 is a table on which the printed circuit board 2 is placed.

The squeegee 5 is in the shape of a horizontally long plate, and its upper edge is held by the holder 6. Two squeegees 5 are arranged at an interval from each other, and cream solder 10 is stored between them. Side plates 7 are fixed to both sides of the squeegee 5 with screws 8. The side plate 7 prevents the cream solder 10 on the mask plate 1 from flowing out to both sides of the squeegee 5. Therefore, when the squeegee 5 is reciprocated in the arrow N1 direction or the arrow N2 direction and slid on the mask plate 1, the cream solder 10 is applied to the electrodes of the circuit pattern of the printed board 2 through the pattern holes 3. Next, when the printed board 2 is lowered and separated from the mask plate 1, the cream solder 10 in the pattern holes 3 is transferred onto the electrodes.

[0006]

In order to make the composition of the cream solder 10 uniform and to densely fill the inside of the pattern holes 3 with the cream solder 10, the cream solder 10 rolls when the squeegee 5 slides. It is desirable to let them knead together. Since the conventional squeegee 5 has a long plate-like shape and slides linearly in the directions of the arrows N1 and N2, as shown by the arrow in FIG.
0 is kneaded while rolling. However, the kneading by the rolling is insufficient and the composition cannot be sufficiently homogenized. Particularly, the vicinity of the surface of the cream solder 10 is oxidized by being exposed to air, and the ratio of the deteriorated material becomes high, and the pattern holes 3 There is a problem that the cream solder 10 is hard to be densely filled therein.

Further, it is extremely difficult to completely bring the side plate 7 into close contact with the side surface of the squeegee 5, and it is unavoidable that a slight gap is formed between the side plate 7 and the side plate 7, and therefore the squeegee 5 is attached. During repeated sliding in the directions of the arrows N1 and N2, part of the cream solder 10 leaks from this gap (see the cream solder indicated by reference numeral 10A in FIG. 6), and the mask plate 1 is soiled. There was a problem that the leaked cream solder 10A had to be removed by cleaning, which required maintenance.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide a screen printing apparatus for cream solder which can be applied to a printed circuit board while sufficiently kneading the cream solder.

[0009]

To this end, according to the present invention, there is provided a movable table arranged above a mask plate of a screen mask having pattern holes, and an X direction for horizontally moving the movable table in the X direction. A moving means, and a Y-direction moving means for horizontally moving the moving base in a Y direction orthogonal to the X direction,
Screen printing device for cream solder, comprising rotating means integrally provided on the moving table and a cylindrical squeegee that stores cream solder inside and is driven by this rotating means to rotate horizontally on the mask plate. Is configured.

[0010]

According to the above structure, the rotating means is driven to rotate the cylindrical squeegee in the horizontal direction, whereby the cream solder stored in the squeegee is sufficiently kneaded and the cream solder is masked. The cream solder can be applied while densely filling the pattern holes of the.

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a perspective view of a screen printing apparatus for cream solder according to an embodiment of the present invention. A screen mask 11 is formed by holding a mask plate 13 on the lower surface of a frame-shaped holder 12, and a pattern hole 14 is formed in the mask plate 13. FIG. 2 is a partial sectional view of a screen printing apparatus for cream solder according to an embodiment of the present invention, in which a printed circuit board 15 is arranged below the mask plate 13. Reference numeral 16 is a table on which the printed circuit board 15 is placed.

In FIG. 1, reference numeral 17 is a base, and No. 4 thereof.
A pillar 18 is erected in the corner. Long base plates 19 and 20 are provided on the upper portion of the column 18. One base plate 1
A ball screw 21 in the X direction is provided on the shaft 9. Two
Reference numeral 2 is a bearing of the ball screw 21. This ball screw 21
Is driven by the X-direction motor 23 to rotate. A guide rail 24 in the X direction is provided in parallel with the ball screw 21. A guide rail 25 in the X direction is also provided on the other base plate 20.

A long plate 26 is horizontally bridged between the base plate 19 and the base plate 20. A nut 27 with which the ball screw 21 is screwed is attached to the end of the long plate 26. Further, sliders 28 slidably fitted on the guide rails 24 and 25 are provided on the lower surfaces of both sides of the long plate 26. Therefore, when the X-direction motor 23 is driven and the ball screw 21 rotates, the long plate 26 horizontally moves in the X-direction.

The ball screw 2 in the X direction is provided on the upper surface of the long plate 26.
1, a Y-direction ball screw 31 orthogonal to 1 is provided, a Y-direction motor 32 for rotating the ball screw 31, and a Y-direction guide rail 33. A moving table 35 is provided on the long plate 26. As will be described later, this moving table 35 moves above the mask plate 13. A slider 36 that is slidably fitted to the guide rail 33 is mounted on the lower surface of the moving table 35. Further, a nut 37 that is screwed into the ball screw 31 is mounted on the back surface of the moving table 35. Therefore, when the Y-direction motor 32 is driven and the ball screw 31 rotates, the moving base 35 horizontally moves in the Y-direction along the guide rail 33.

A rotation direction motor 41 is installed on the moving table 35. As shown in FIG.
A rear end portion of a rotary plate 43 is attached to the rotary shaft 42, and a squeegee 44 is attached to a front end portion of the rotary plate 43. The squeegee 44 is a cylindrical body without a bottom with a lid, and a grounding element 45 made of hard rubber or hard resin that is grounded to the mask plate 13 is integrally fixed to the lower portion of the squeegee 44. The squeegee is not limited to a cylindrical body, and may be a cylindrical body such as a polygonal cylindrical body, or may be a cylindrical body without a lid and a bottom, but as in the present embodiment, it is a cylindrical body with a lid and a bottom. If the airtightness is secured in the state of being grounded to the mask plate 13, it becomes possible to strictly control the temperature and humidity inside the squeegee 44 and prevent the deterioration of the material of the cream solder 10.

As shown in FIG. 2, the rotation shaft 42 of the rotation direction motor 41 and the center axis of the squeegee 44 are eccentric, and when the rotation direction motor 41 is driven, the squeegee 44 rotates horizontally about the rotation shaft 42. To do. When the X-direction motor 23 and the Y-direction motor 32 are driven as described above, the squeegee 44 horizontally moves in the X-direction and the Y-direction integrally with the moving table 35. Reference numeral 46 denotes a cap that is detachably attached to the upper portion of the squeegee 44. By removing the cap 46, the cream solder 10 is replenished inside the squeegee 44.

In FIG. 2, nuts 51a and 51b are mounted on both sides of the table 16.
Vertical ball screws 52a and 52b are screwed into the shaft 1. One ball screw 52a is driven by the Z-direction motor 53 to rotate. Ball screw 52a and ball screw 52b
Timing pulleys 54a and 54b are attached to the timing pulleys 54a and 54b, and a timing belt 55 is attached to the timing pulleys 54a and 54b. Therefore, the Z-direction motor 5
When 3 is driven, the ball screws 52a and 52b rotate simultaneously, and the table 16 on which the printed circuit board 15 is placed moves up and down.

This cream solder screen printing apparatus has the above-mentioned structure, and the overall operation will be described below.

As shown in FIG. 2, the Z-direction motor 53 is driven to raise the printed circuit board 15, and the upper surface thereof is brought close to the lower surface of the mask plate 13. Then, the X-direction motor 23 is driven to move the long plate 26 and the moving base 35 in the X-direction, while the rotation direction motor 41 is driven to drive the squeegee 44.
If the squeegee 44 is rotated horizontally about the rotary shaft 42,
The cream solder 10 stored inside is kneaded while rolling as shown by the arrow in FIG. 4, and densely filled in the pattern holes 14.

FIG. 3 shows the locus Q of the squeegee 44. The squeegee 4 is driven by driving the X-direction motor 23.
4 moves in the X1 direction, and when it has moved to the end of the printed circuit board 15, the driving of the X direction motor 23 is stopped, the Y direction motor 32 is driven, and the squeegee 44 is slightly moved in the Y1 direction. Next, by driving the rotation direction motor 41 while driving the X direction motor 23 in the reverse direction, the squeegee 44 is moved in the X2 direction while being horizontally rotated. Thereafter, by moving the squeegee 44 in the Y2 direction and the X1 direction in the same manner, the squeegee 44 is moved to the printed circuit board 15
All the pattern holes 14 can be filled with the cream solder 10 by sliding so as to cover the entire surface of the cream solder 10.

Next, in FIG. 2, when the Z-direction motor 53 is driven in the opposite direction, the table 16 descends, the printed circuit board 15 is separated from the mask plate 13, and the cream solder 10 in the pattern 14 is transferred to the printed circuit board 15. After being transferred to the electrodes of the circuit pattern, the application process of the cream solder 10 is completed.

[0023]

As described above, according to the present invention, it is possible to densely fill the pattern holes of the mask plate while sufficiently kneading the cream solder, so that the cream solder having a good shape can be applied to the printed board. In addition, if the squeegee has a closed-bottomed tubular shape to ensure airtightness, it is possible to control the temperature and humidity inside the squeegee and prevent the deterioration of the material of the cream solder stored inside the squeegee. Further, by limiting the moving range of the squeegee, it is possible to limit the application range of the cream solder, and thus it is possible to apply the cream solder only to a desired area of the printed board.

[Brief description of drawings]

FIG. 1 is a perspective view of a screen printing apparatus for cream solder according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of a screen printing apparatus for cream solder according to an embodiment of the present invention.

FIG. 3 is a plan view of a screen mask of a screen printing apparatus for cream solder according to an embodiment of the present invention.

FIG. 4 is a side view of a main part of the conventional cream solder screen printing apparatus during cream solder application.

FIG. 5 is a front view of a main part of the conventional cream solder screen printing apparatus during cream solder application.

FIG. 6 is a plan view of a main part of the conventional cream solder screen printing apparatus during cream solder application.

[Explanation of symbols]

 10 Cream Solder 11 Screen Mask 13 Mask Plate 14 Pattern Hole 21, 31 Ball Screw 23 X Direction Motor 27, 37 Nut 32 Y Direction Motor 35 Moving Base 41 Rotation Direction Motor 42 Rotation Shaft 44 Squeegee

Claims (2)

[Claims] 1. A moving table arranged above a mask plate of a screen mask having pattern holes, X-direction moving means for horizontally moving the moving table in the X direction, and the moving table in the X direction. Y-direction moving means for horizontally moving in a Y-direction orthogonal to the moving direction, rotating means integrally provided on the moving base, and cream solder stored inside and driven by the rotating means to horizontally move on the mask plate. A screen printing device for cream solder, comprising: a cylindrical squeegee that rotates in a direction. 2. The screen printing apparatus for cream solder according to claim 1, wherein the squeegee is a cylindrical body with a lid and a bottom.