JPH03270938A - Screen printing machine - Google Patents

Abstract

PURPOSE:To enable effective screen printing to be performed even for green sheets having different dimensions and shapes by a method wherein a pushing member having elastic force to be arranged below a screen and a support member supporting the pushing member freely displaceably conforming to a size of the green sheet are established. CONSTITUTION:The screen printing machine is composed of a printing base 22 on which a green sheet 40 is put fixedly, a plate frame 25 to which a screen is disposed in tension, a processing part 23 consisting of pushing members having elastic force, and supporting members 24a, 24b which support freely displaceably the pushing member conforming to a size of the green sheet. The pushing member can be thereby brought into contact with the green sheet having a different size and a different shape also. Consequently, the green sheet 40 can be avoided from being transferred to the plate frame side following displacement of the squeegee. Further, since an end part of the green sheet is positioned with the pushing member, screen printing can be effectively performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a screen printing machine. By improving the interaction between the board and the screen, it is possible to provide a circuit board of excellent quality, and the size of the board,
The present invention relates to a screen printing machine that can perform efficient screen printing in accordance with the size etc. even if there is a difference in shape.

[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. 4a and 4b.

In other words, the 41st! In la, first, a substrate to be printed, for example, a green sheet 4 is placed at a predetermined position on the printing table 2.
Place. Next, a vacuum is drawn through the holes 6a to 6f formed in the printing table 2, and the squeegee 10 is pressed and displaced on the screen 8 while preventing the green sheet 4 from shifting. That is, screen 8
is pressed against the green sheet 4, and at the same time, the paste 12 is passed through so as to be embedded in the holes defining the desired pattern previously formed on the screen 8. As a result, the paste 12 in a desired pattern is applied onto the green sheet 4. When the squeegee 10 is displaced on the screen 8, the portion of the screen 8 on which 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 4, paste 12
After being applied, the adhesive force of the paste 12 exceeds the exhaustion force caused by vacuuming and the gravity generated by the weight of the green sheet 4, so that it 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,
The inconvenience that the green sheet 4 is damaged and cannot be put to practical use has become apparent.

When the green sheet 4 is attached to the screen 8 side for a long time, a part of the paste 12 applied to the green sheet 4 is spread to the screen 8, and the thickness of the paste 12 varies. will occur. 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 this depression has the disadvantage that when screen printing is attempted to be performed on the green sheet 4 again in this step and the next step, a sufficient circuit pattern etc. cannot 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. By making it uniform, it is possible to form circuit boards of excellent quality, and even if there are differences in the size and shape of the green sheets, efficient screen printing can be performed. Our goal is to provide a screen printing machine that can.

[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. and a pressing member with elasticity disposed below the screen in the plate frame, and a support that supports the pressing member so that it can be displaced according to the size of the green sheet. It is characterized by being composed of members.

[Operation] In the screen printing machine according to the present invention configured as described above, the substrate is pressed during printing by the pressing member having elastic force. At this time, the pressing member is held movably relative to the supporting member. Therefore, the pressing member is displaced in accordance with the size and shape of the substrate, and therefore the pressing member can be brought into contact with substrates having different sizes and shapes. As a result, it is possible to avoid the substrate from being transferred to the plate frame side due to displacement of the squeegee.

Furthermore, since the pressing member has elastic force,
This elastic force lifts the plate frame, thereby further promoting the cleanliness of the green sheet. Moreover, in order to position the end of the green sheet with this pressing member,
This avoids damage to the green sheet, eliminates the need to increase vacuum suction power, and produces circuit boards of excellent quality.
Efficient screen printing can be performed.

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

In FIGS. 1a, b to 2, reference numeral 20 indicates a screen printing machine according to the present invention, and the screen printing machine 20 basically includes a printing table 22, a plate making section 23,
It is composed of a support member 24a124b.

The plate making section 23 has a rectangular plate frame 25 that is a combination of four plate frame members each having a negative side of, for example, 450 mm. A screen 26 made of, for example, a 200 to 250 mesh stainless steel mesh is attached to the inside of the plate frame 25. The screen 26 has a coarse portion that matches the pattern in order to apply a desired pattern by passing the paste with a squeegee, which will be described later.

The columnar support members 24a and 24b are arranged parallel to each other along the outer sides of opposing parallel plate frame members of the plate frame 25. Elongated holes 28a to 28d for positioning the printing frame are formed on each support member 24a124b from above to below, and elongated holes for positioning a pressing member are formed on the side surfaces of each of the support members 24a and 24b. 30a and 30b are bored.

In this case, the flat plates 32a to 32d are respectively projected from the corners of the frame 25 and fastened to the supporting members 24a and 24b with bolts. On the other hand, the long support members 24a and 24b
An angle member 34 is provided in each of the elongated holes 30a and 30b.
The bolts to be screwed into parts a to 34d are exposed. Screw these bolts into the angle members 34a to 34d, and
The angle member 34a is pressed against the side surfaces of the angle members 4a and 24b.
34d to 34d.

Next, the lower surface of the printing frame 25 has a thickness of, for example, 2 mm.
Pressing members 36a and 36b made of silicone rubber having a hardness of 20° to 40° are fixed with double-sided tape or the like.

The pressing members 36a and 36b 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 has a large number of vacuum intake holes 38 at both bottoms.

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

First, as shown in FIGS. 1a and 1s, the printing table 2 is
A green sheet 40, which is a printing material, is placed and positioned at a predetermined position of 2. In this example, 0.
A 13 mm green sheet 40 was used. Then, the plate making unit 23 is brought close to the printing table 22 on which the green sheet 40 is placed, and the pressing members 36a and 36b are pressed against the green sheet 40.
0 close enough to be able to press it.

On the other hand, a vacuum suction source (not shown) is energized to apply negative pressure to the green sheet 40 through the vacuum suction hole 38 to attract it. At this time, a gap is created between the surface of the green sheet 40 and the screen 26 with a height equal to the thickness of the green sheet 40 subtracted from the thickness of the pressing members 36a and 36b. The height of the gap at this time is l mm to 'l mm.
is suitable.

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/am2 to this squeegee 60, and
It is displaced on the screen 26 at a speed of 150 nm/sec to 150 nm/sec. As a result, the paste 50
The paste is passed through the coarse portion of the screen 26 and applied onto the green sea 40 in the 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 36a and 36b, and the many vacuum holes 38 of the printing table 22
Since negative pressure is suctioned through the printing table 22, it is fixed to the printing table 22.

Therefore, when the squeegee 60 is displaced in the direction of arrow A,
Since the pressing members 36a and 36b 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 36a and 36b are made of silicone rubber with high elasticity, the ends of the green sheet 40 are not deformed.

FIG. 3 shows yet another embodiment of the present 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, a plate frame holder 70 is provided to hold the plate frame 25. Elongated holes 72a and 72b are formed in a pair of frame members 71a and 71b facing each other in the frame holder 70, respectively, and angle members 74a to 74d that lock the pressing members 36a and 36b are fixed with bolts 76a and 76b. Screw together and hold.

In this way, as in the previous embodiment, any size of plate frame can be used. Of course, the plate frame holder 70
Needless to say, it is fixed to the main body of the printing press.

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 machine 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 is 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. 1a is a perspective explanatory view showing a schematic configuration of the main parts of the screen printing machine according to the present invention; FIG. 1 is a vertical cross-sectional view of the main parts of the screen printing machine shown in FIG. d is a schematic longitudinal sectional view showing the operating state of the screen printing machine according to the present invention, FIG. 3 is an exploded perspective view of another embodiment of the screen printing machine according to the present invention, and FIGS. 4a and b are conventional techniques. FIG. 2 is a schematic vertical cross-sectional view showing the operating state of the screen printing machine according to the invention. O... Screen printing machine 2... Printing table 3... Plate making section 5... Plate frame 6... Screens 6a, 36b... Pressing member 0... Green sheet 0... Paste 0...Squeegee 0...Form frame holder 1a, 71b...Frame member 2 a, 72 b-...Long hole 4a to 74d...Angle member 6a, 76b...Bolt FIG, 2c Δ FIG , 2d mu

Claims (3)

[Claims] (1) A printing table on which a green sheet is placed, a plate frame placed above the printing plate and having a screen for pattern printing stretched over it, and a bullet plate placed below the screen in the plate frame. 1. A screen printing machine comprising: a plate-making section comprising a forceful pressing member; and a supporting member movably supporting the pressing member according to the size of a green sheet. (2) The screen printing machine according to claim 1, wherein the columnar support member is a rail member provided along each outer edge of the plate frame material parallel to the moving direction of the squeegee. screen printing machine. (3) In the screen printing machine according to claim 1, the supporting member comprises a plate frame holder located above the plate making section, and the plate frame holder holds the pressing member movably through plate making fixing means. A screen printing machine featuring