JP3001552B1 - Cream solder printing method and apparatus - Google Patents

Abstract

A cream solder printing method and apparatus include:
Improve the removability of cream solder and reduce soldering defects. A method of printing a cream solder on a substrate by bringing a metal mask 1 into close contact with a substrate 16 and filling cream openings 14 into openings 17 of the metal mask,
After the cream solder is filled, a higher tension is applied to the metal mask than at the time of filling to expand the opening, and thereafter, the metal mask is separated from the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cream solder printing method and apparatus for printing cream solder on a substrate on a printed wiring board or the like using a metal mask.

[0002]

2. Description of the Related Art Conventionally, when printing cream solder on a printed wiring board or the like, first, a metal mask is brought into close contact with the printed wiring board, and the squeegee slides the cream solder into a mask opening formed at a predetermined position of the metal mask. And transferring the solder to the printed wiring board by separating the metal mask and the printed wiring board.

[0003]

However, the above-mentioned conventional cream solder printing means has the following problems. That is, the transfer of the cream solder to the printed wiring board is performed when the metal mask is released from the plate, but the transfer rate at that time is poor. The deterioration of the transfer rate of the cream solder causes a soldering failure such as a solder bridge or unsolder. Further, the cream solder remaining in the mask opening after the transfer deteriorates the transfer rate of the next print, so that the mask must be cleaned frequently. The reason is that the cream solder filled in the mask opening comes into close contact with the wall surface of the mask opening.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a cream solder printing method and apparatus capable of improving the removability of cream solder and reducing soldering defects. .

[0005]

The present invention has the following features to attain the object mentioned above. In other words, the cream solder printing method according to claim 1 is a method of printing a cream solder on a substrate by bringing a metal mask into close contact with the substrate and filling the opening of the metal mask with the cream solder. A technique is employed in which after the solder is filled, a higher tension is applied to the metal mask than at the time of filling to expand the opening, and thereafter, the metal mask is separated from the substrate.

According to a second aspect of the present invention, there is provided a cream solder printing apparatus for printing a cream solder on a substrate by placing a metal mask on the substrate and filling the opening of the metal mask with the cream solder. A tension mechanism for applying arbitrary tension to the metal mask is provided, and the tension mechanism includes:
A technique is employed in which, when the metal mask is separated from the substrate after filling the cream solder, a higher tension is applied to the metal mask than at the time of filling.

According to a third aspect of the present invention, in the cream solder printing apparatus according to the second aspect, the pulling mechanism includes a ball screw having a tip connected to a peripheral portion of the metal mask; A technique including a pulse motor that rotates and advances and retracts the metal mask is employed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a cream solder printing method and apparatus according to the present invention will be described with reference to FIGS.
This will be described with reference to FIG. In these figures, reference numeral 1
Is a metal mask, 2 to 5 are mesh portions, 6 to 9 are frames, and 10 to 13 are printing apparatus side cylinders.

In the cream solder printing apparatus according to the present embodiment, as shown in FIG. 1, a metal mask 1 is connected to frames (mask frames) 6 to 9 via mesh portions 2 to 5, and mesh portions 2 to 5 The frames 6 to 9 are divided in four directions of the metal mask 1. The metal mask 1 has a transfer mask opening 17 in which cream solder is filled at a predetermined position.

The frames 6 to 9 can be fixed to the ends of the pistons of the printing apparatus cylinders 10 to 13 (pulling mechanisms), and connect the frames 6 to 9 to the printing apparatus cylinders 10 to 13. Thus, the metal mask 1 is fixed to the printing device. Further, the printing apparatus side cylinders 10 to 13 are connected to the control unit C, respectively, and driven by the control unit C to pull the metal mask 1 with a predetermined tension via the frames 6 to 9.
That is, the metal mask 1 is configured so that an arbitrary tension is applied in an arbitrary direction by the printing apparatus side cylinders 10 to 13 arranged in all directions.

Next, the cream solder printing method according to the present embodiment will be described with reference to FIG.

First, as shown in FIG. 2A, a cream solder 14 is applied on the metal mask 1 and filled in the mask opening 17 while being pressed by a squeegee 15 to form a printed wiring board (substrate) 16. Supply on top. At this time, the metal mask 1 is not moved by the movement of the squeegee 15 on the frames 6 to 9 connected in each direction of the metal mask 1 by the printing apparatus side cylinders 10 to 13 driven by the control unit C. Only tension is applied.

When the movement of the squeegee 15 is completed, as shown in FIG. 2B, the control unit C drives the printing apparatus side cylinders 10 to 13 to print the frames 6 to 9 (at the time of filling). An even stronger tension is applied, and the metal mask 1 is pulled from each direction (square). As a result, the mask opening 17 has a shape wider than that at the time of printing, and the cream solder 14 adhered to the wall surface of the mask opening 17.
Moves away from the wall.

Next, as shown in FIG. 2 (c), the plate is separated from the printed wiring board 16 and the metal mask 1 in a state where the above tension is applied. The cream solder 14 having the same shape as 17 is printed. That is, the metal mask 1 filled with the cream solder 14 by the squeegee 15 is applied with an arbitrary higher tension in each direction when the printed wiring board 16 is separated. Therefore, in the present embodiment, the transfer rate of the cream solder 14 to the printed wiring board 16 is increased by changing the tension of the metal mask 1 at the time of separation of the plate, and higher quality solder printing can be performed.

Next, a second embodiment of a cream solder printing method and apparatus according to the present invention will be described with reference to FIG.

The difference between the second embodiment and the first embodiment is that, in the first embodiment, the printing apparatus side cylinders 10 to 13 serve as a pulling mechanism for applying an arbitrary tension to the metal mask 1.
On the other hand, in the second embodiment, as shown in FIG. 3, ball screws 22 to 25 whose distal ends are connected to the peripheral portion of the metal mask 1, as shown in FIG. Pulse motors 18 to 21 that rotate the metal mask 1 by rotating the metal mask 1 by rotating the metal mask 1.

That is, in the cream solder printing apparatus of the second embodiment, the tips of the ball screws 22 to 25 are fixed to the frames 6 to 9, respectively, so that they are connected to the peripheral edge of the metal mask 1 and the pulse motors 18 to Reference numerals 21 are respectively connected to the control unit C, and drive control is performed by the control unit C. Arbitrary tension is applied to the metal mask 1 attached to the printing apparatus by pulse motors 18 to 21 and ball screws 22 to 25 via frames 6 to 9. Adjustment of the tension applied to the metal mask 1 is performed by the pulse motors 18 to 21 and the ball screw 22 controlled by the control unit C.
To 25, the amount of movement of frames 6 to 9 is set.

In the cream solder printing apparatus according to the present embodiment, similarly to the first embodiment, after the cream solder is filled,
When the printed wiring board and the metal mask 1 are separated from each other,
Drives the pulse motors 18 to 21 to pull the metal frame 1 with a higher tension than at the time of filling to print cream solder. In this embodiment, the frame 6
9 can be finely adjusted, so that the metal mask 1 can be finely aligned with the printed wiring board. Also,
Since the tension of the metal mask 1 can be arbitrarily set, a soft material such as resin can be used.

[0019]

According to the present invention, the following effects can be obtained. (1) According to the cream solder printing method of the first aspect and the cream solder printing apparatus of the second aspect, a higher tension is applied to the metal mask than at the time of filling to expand the opening and separate the metal mask from the substrate. In addition, when the plate is separated, the opening is widened, and the detachability of the solder is improved. Therefore, the amount of solder supplied to the substrate is stabilized, and soldering defects such as solder bridges and unsoldering can be reduced. Furthermore, since the amount of cream solder adhering to the opening after printing can be reduced, continuous printing can be improved, and the number of times of cleaning the mask can be reduced.

(2) According to the cream solder printing device of the third aspect, the pulling mechanism pulls the metal mask by rotating and moving the ball screw whose tip is connected to the peripheral edge of the metal mask. Since a pulse motor is provided, the amount of movement of the metal mask can be finely adjusted, and fine positioning of the metal mask with respect to the substrate can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part showing a cream solder printing method and apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part showing a printing procedure in a cream solder printing method and apparatus according to a first embodiment of the present invention.

FIG. 3 is a plan view of a main part showing a second embodiment of the cream solder printing method and apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal mask 10-13 Printer side cylinder (pulling mechanism) 14 Cream solder 16 Printed wiring board (substrate) 17 Mask opening (opening) 18-21 Pulse motor 22-25 Ball screw

Claims (3)

(57) [Claims] 1. A method of printing a cream solder on a board by filling a cream mask into an opening of the metal mask by bringing a metal mask into close contact with the board, and after filling the cream solder, A cream solder printing method, comprising applying a high tension to the metal mask to widen the opening, and thereafter separating the metal mask from the substrate. 2. An apparatus for printing a cream solder on a substrate by filling the opening of the metal mask with the cream solder by bringing the metal mask into close contact with the substrate, and applying an arbitrary tension to the metal mask. A cream mechanism, wherein the tensioning mechanism is set so as to apply a higher tension to the metal mask when the cream mask is filled and the metal mask is separated from the substrate after the cream solder is filled. Printing device. 3. The cream solder printing apparatus according to claim 2, wherein the pulling mechanism comprises: a ball screw having a tip connected to a peripheral portion of the metal mask; and rotating the ball screw to advance and retract the metal mask. A cream solder printing device comprising a pulling pulse motor.