JPH03270937A - Screen printing machine - Google Patents

Abstract

PURPOSE:To improve a snap off of a green sheet and a screen by avoiding sticking of both by a method wherein a processing part composed of a printing base on which the green sheet is put fixedly and a plate frame to which the screen is disposed in tension is provided, and a pushing member having elasticity is provided to the plate frame. CONSTITUTION:A processing part 23 composed of a printing base 22 on which a green sheet 40 is fixedly put and a plate frame 24 to which a screen 26 for pattern printing arranged above the printing base is disposed in tension is established, and pushing members 28a, 28b having elasticity are arranged to the frame. Therefore, in the case where a squeegee 60 is displaced, since the pushing members 28a, 28b push an end part of the green sheet 40, the green sheet 40 is never transferred to the screen 26 side by adhesion of a paste 50. Further, a snap off property can be steeply improved because of a clearance to be generated by a thickness of the pushing member and its elasticity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a screen printing device.More specifically, when forming an electronic circuit or the like by screen printing a desired paste pattern on a substrate, The present invention relates to a screen printing device that improves the performance between the board and the screen, thereby making it possible to provide a circuit board of excellent quality.

[Prior Art] Generally, when creating an electronic circuit or the like in a multilayer wiring circuit board or the like, there is a method of screen printing a desired pattern on the board.

This type of prior art is shown in FIGS. 6a and 6b.

That is, in FIG. 6a, first, a substrate to be printed, for example, a green sheet 4, is placed at a predetermined position on the printing table 2. As shown in FIG. Next, the hole 6 formed in the printing table 2
Vacuuming is performed through the holes 6f to press and displace the squeegee 10 on the screen 8 while preventing the green sheet 4 from shifting. That is, the screen 8 is pressed against the green sheet 4, and at the same time, the paste 1 is applied to the holes defining the desired pattern previously formed on the screen 8.
Let it pass by embedding 2. As a result, the paste 12 in a desired pattern is applied onto the green sheet 4.

Then, if the squeegee 10 is displaced on the screen 8,
The screen 8 in the area where the pattern has already been applied is separated from the green sheet 4 due to its elastic force.

[Problems to be Solved by the Invention] However, when the circuit board on which the desired paste pattern is printed is relatively thin, that is, the green sheet 4
If the paste is thin, as shown in Figure 6, the paste 12
After the paste 12 is applied, the adhesive force of the paste 12 exceeds the suction force caused by vacuuming and the gravity generated by the weight of the green sheet 4, so that the paste 12 separates from the printing table 2 and transfers to the screen 8. Therefore, when trying to peel off the green sheet 4 attached to the screen 8 from the screen 8, the green sheet 4 is damaged and cannot be put to practical use.

Moreover, when the green sheet 4 adheres to the screen 8 side, the paste 12 applied to the green sheet 4
A portion of the paste 12 is diffused onto the screen 8, causing variations in the coating thickness and bleeding of the paste 12. This means that in some cases, there is a possibility that problems such as poor electrical insulation may occur after the product is completed.

Therefore, in order to overcome the above-mentioned disadvantages, when screen printing a desired pattern on the relatively thin green sheet 4, a method may be considered in which the suction force of vacuuming performed through the holes 6a to 6f is increased. However, if the suction force of the vacuum exceeds the material strength of the green sheet 4, the holes 6 in the soft green sheet 4
This causes depressions due to the suction force at the portions a to 6f that come into contact with each other. The presence of these depressions has the disadvantage that when screen printing is attempted to be performed on the green sheet 4 again in the same process or in the next process, a circuit pattern etc. sufficient for practical use will not be formed.

Therefore, an object of the present invention is to avoid the adhesion of the green sheet and the screen, and also to improve the performance of the green sheet and the screen so that the green sheet is not damaged and the thickness of the applied paste is reduced. It is an object of the present invention to provide a screen printing apparatus that can make circuit boards uniform in quality and form circuit boards of excellent quality.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a printing table on which a green sheet is placed, and a plate frame arranged above the printing table and having a screen for pattern printing stretched thereon. It is characterized in that it has a plate-making section consisting of a plate-making section, and a pressing member with elasticity is disposed on the plate frame.

[Function] In the screen printing apparatus according to the present invention configured as described above, the substrate can be pressed during printing by the pressing member having elastic force. Therefore, it is possible to avoid the substrate from being transferred to the plate frame side due to the displacement of the squeegee. Furthermore, since the pressing member has a resilient force, it lifts the printing frame on the one hand, thereby further promoting the processing of the green sheet. Moreover, since the end of the green sheet is positioned using a pressing member with elastic force, damage to the green sheet is avoided, and there is no need to increase the vacuum suction force.
A circuit board with excellent quality can be obtained.

[Embodiments] Next, preferred embodiments of the screen printing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

1 to 3, reference numeral 20 indicates a screen printing apparatus according to the present invention, and the screen printing apparatus 20 basically includes a printing table 22 and a plate-making section 23. As shown in FIG.

The plate making section 23 has a rectangular plate frame 24 which is a combination of four plate frame members each having a side of, for example, 450 mm. Print frame 2
A screen 26 made of, for example, a 200 to 250 mesh stainless steel mesh is attached to the inner peripheral portion of the screen 4 . The screen 26 has coarse portions that match the desired pattern in order to apply the desired pattern by communicating the paste. Next, the lower surface of the printing frame 24 has a thickness of, for example, 2 mm.

Pressing members 28a and 28b made of silicone rubber having a hardness of 20° to 40° are fixed with double-sided tape or the like.

The pressing members 28a and 28b are arranged parallel to each other and in accordance with the displacement direction of a squeegee, which will be described later. On the other hand, the printing table 22 is defined with a large number of vacuum suction holes 32a to 32f.

The screen printing apparatus according to the present invention is basically constructed as described above, and its operation and effects will be explained next.

First, as shown in FIG. 2a, a green sheet 40, which is a printing material, is placed and positioned at a predetermined position on the printing table 22. In this example, a green sheet 40 with a thickness of 0.13 mm was used. Then, the plate making unit 23 is brought close to the printing table 22 on which the green sheet 40 is placed,
The pressing members 28a and 28b bring the green sheet 40 close to each other to a distance where they can sufficiently press it.

On the other hand, a vacuum suction source (not shown) is activated to apply negative pressure to the green sheet 40 through the vacuum suction holes 32a to 32f to attract it. Note that at this time, pressing members 28a and 28 are provided between the surface of the green sheet 40 and the screen 26.
A gap having a height obtained by subtracting the thickness of the green sheet 40 from the thickness b is created. The height of the gap at this time is preferably 1 mm to 2 m.

After fixing the green sheet 40 to the printing table 22 in this manner and bringing the plate making section 23 close to it, the paste 50 is applied.

First, a film with a viscosity of 7,000 to 14,000 is placed on the screen 26.
A CPS paste 50 is placed on top with a width sufficient to cover the entire green sheet 40.

Next, using a squeegee 60 made of hard rubber, apply a force of 1.5 to 3 kg/cm2 to this squeegee 60, and
It is displaced on the screen 26 at a speed of from mm/sec to 150 mm/sec. As a result, the paste 50 is passed through the coarse portion of the screen 26 and applied onto the green sheet 40 in a desired paste pattern. At this time, as shown in FIGS. 2a to 2d, both ends of the green sheet 40 are pressed by the pressing members 28a and 28b, and the many vacuum holes 32a of the printing table 22 are pressed.
It is fixed to this printing table 22 because negative pressure is suctioned through 32f to 32f.

Therefore, when the squeegee 60 is displaced in the six directions of arrows,
Since the pressing members 28a and 28b press the ends of the green sheet 40, the green sheet 40 will not be transferred to the screen 26 side due to the adhesive force of the paste 50.

Moreover, since the pressing members 28a and 28b are made of silicone rubber with high elasticity, the ends of the green sheet 40 are not deformed.

FIG. 4 shows yet another embodiment of the invention.

In this embodiment, the same components as those in the previous embodiment are given the same reference numerals, detailed explanations thereof are omitted, and the same applies hereinafter. In this embodiment, the squeegee 6 is moved in the direction of arrow A.
When the squeegee 60 is displaced, the pressing members 28a and 28b are arranged parallel to the moving direction of the squeegee 60. Note that the pressing members 28a and 28b may be provided in a rectangular shape so as to press the four circumferences of the green sheet 40.

FIG. 5 shows another embodiment of the present invention.

In this embodiment, three female screw portions 70a to 70c are formed in a part of the printing frame 24 in the width direction, and a long hole 7 is formed in the printing frame 24.
A bracket 74 that defines a portion 2 is fitted therein. Pressing members 28a and 28b are fixed to the lower surface of this bracket 74. Note that the bracket 74 is secured to the plate frame 24 via bolts 76.

Therefore, if the bolt 76 is selectively screwed into any of the female threaded portions 70a to 70c, the pressing member 28a is substantially
It is also possible to adjust the width of 128b.

According to the present invention, the green sheet 40 is prevented from adhering to the screen 26 by the paste, and the separation property between the screen 26 and the green sheet 40 is significantly improved. This makes it possible to make the thickness of the paste uniform without damaging the green sheet 40, and as a result, it is possible to obtain a circuit board of excellent quality.

[Effects of the Invention] As described above, according to the screen printing apparatus according to the present invention, by fixing the pressing member to the lower side of the plate frame member, adhesion between the screen and the printing material during squeezing can be prevented. Furthermore, the plate release property can be significantly improved due to the gap created by the thickness of the pressing member and its elastic force. Therefore, it is possible to obtain a circuit board of excellent quality without damaging the printing material and by keeping the thickness of the paste constant.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a screen printing device according to the present invention, FIG. 2 is a schematic vertical cross-sectional view showing the operating state of the screen printing device according to the present invention, and FIG. 3 is a screen according to the present invention. FIG. 4 is a resolution perspective view of a printing device; FIG. 4 is a resolution perspective view of another embodiment of the present invention; FIG. 5 is a schematic partial vertical cross-sectional view of another embodiment of the present invention; FIG. FIG. 2 is a schematic vertical cross-sectional view of such a screen printing device. 20... Screen printing device 22... Printing stand 23... Plate making section 24... Plate frame 26... Screens 28a, 28b... Pressing member 40... Green sheet 50... Paste 60...Squeegee 70~70c...Female thread part 72...Long hole 74...Bracket 76...Bolt 3AQ Also b ZCI jZ↑ A--1-CH FIG, 2c FIG, 2d FIG, 6a 10 FIG, 6b

Claims (4)

[Claims] (1) It has a plate-making section consisting of a printing table on which a green sheet is placed, and a plate frame arranged above the printing plate and having a screen for pattern printing stretched over it, and the plate frame has elasticity. A screen printing device characterized in that a pressing member is provided. (2) The screen printing device according to claim 1, wherein the pressing member is provided parallel to a direction orthogonal to the moving direction of the squeegee. (3) The screen printing apparatus according to claim 1, wherein one set of pressing members is provided in a direction parallel to the direction of movement of the squeegee. (4) The screen printing device according to any one of claims 1 to 3, wherein the pressing member is configured to be freely displaceable with respect to the plate frame.