JPH0585353B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a screen printing machine, and more particularly, the present invention relates to a screen printing machine that prints a desired paste pattern on a substrate to form an electronic circuit or the like. This improves the separation between the plate and the screen, thereby making it possible to provide circuit boards of excellent quality, and even if there are differences in the size and shape of the boards, The present invention relates to a screen printing machine capable of correspondingly efficient screen printing.

[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.
That is, in FIG. 4a, 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, 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, the 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 formed in advance on the screen 8. As a result,
A 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, when the green sheet 4 is thin, the paste 12 is After being 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 it separates from the printing table 2 and transfers to the screen 8. Therefore, when attempting to peel off the green sheet 4 attached to the screen 8, the green sheet 4 is damaged and cannot be put to practical use.

Furthermore, if the time that the green sheet 4 is attached to the screen 8 side becomes longer, a part of the paste 12 applied to the green sheet 4 will be diffused to the screen 8, and the thickness of the applied paste 12 will vary. 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 turn 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 soft green sheet 4 will have depressions due to the suction force in the portions that contact the holes 6a to 6f. 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 adhesion between the green sheet and the screen, and also to improve separation between the green sheet and the screen, thereby preventing damage to the green sheet and reducing the thickness of the applied paste. By making the green sheets 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 for holding down the edge of the green sheet made of an elastic material, which is disposed under the plate frame, and the supporting member supports the green sheet. It is characterized in that the pressing member is supported so as to be able to be displaced according to the size.

[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 an elastic force, on the one hand, this elastic force lifts the plate frame, thereby further promoting separation of the green sheet from the plate. Moreover, since the end of the green sheet is positioned by this pressing member, damage to the green sheet is avoided, and there is no need to increase the vacuum suction force.
Not only can a circuit board of excellent quality be obtained, but also 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 2
0 indicates a screen printing machine according to the present invention, and the screen printing machine 20 basically includes a printing table 2.
2, a plate making section 23, and supporting members 24a and 24b.

The plate making section 23 has a rectangular plate frame 25 that is a combination of four plate frame members each having a side of, for example, 450 mm. For example, 200 to 250
A screen 26 made of mesh stainless steel is attached. The screen 26 has a coarse portion that matches the pattern in order to apply the paste in a desired pattern by passing the paste through it using 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. Each support member 24a, 24
Elongated holes 28a to 28d for positioning the plate frame are formed on the top of the plate frame b, and the holes 28a to 28d penetrate from above to below.
Elongated holes 30a, 30b for positioning the pressing member are bored in the side surfaces of the support members 24a, 24b, respectively.

In this case, the flat plates 32a to 32d are made to protrude from the corners of the frame 25, respectively, and the supporting members 24a,
24b with bolts. On the other hand, bolts to be screwed into the angle members 34a to 34d are provided in the elongated holes 30a and 30b of the long support members 24a and 24b, respectively. By screwing these bolts into the angle members 34a to 34d, the support member 24
The angle member 3 is pressed against the side surfaces of a and 24b.
Attempt to position 4a to 34d.

Next, pressing members 36a and 36b made of silicone rubber having a thickness of 2 mm and a hardness of 20° to 40° are fixed to the lower surfaces of the angle members 34a to 34d with double-sided tape or the like. The pressing members 36a and 36d 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 3.
8 is defined.

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 1b, 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 0.13 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 member 3
6a and 36b bring the green sheet 40 close enough to be able to press it sufficiently.

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, there is a gap between the surface of the green sheet 40 and the screen 26 due to the thickness of the pressing members 36a and 36b.
A gap with a height equal to the thickness is created. The height of the gap at this time is preferably 1 mm to 2 mm.

In this way, the green sheet 4 is placed on the printing table 22.
0 is fixed and the plate-making section 23 is brought closer, and then the paste 50 is applied.

First, the viscosity is 7000 on the screen 26.
14000CPS paste 50 and green sheet 40
Lay it on top with enough width to cover the whole thing.

Next, using a squeegee 60 made of hard rubber,
Apply a force of 1.5 to 3 kg/cm ² to this squeegee 60,
Screen 2 at a speed of 80mm/sec to 150mm/sec
6 Displace the top. As a result, the paste 50
is passed through the coarse portion of the screen 26 and applied onto the green sheet 40 as a desired paste pattern. At this time, as shown in FIGS. 2a to 2d, the green sheet 40 is pressed against the pressing member 36a.
It is fixed to the printing table 22 because both ends are pressed by the printing table 36b, and negative pressure is sucked through the many vacuum suction holes 38 of the printing table 22.

Therefore, when the squeegee 60 is displaced in the direction of the arrow A, the pressing members 36a and 36b press the end portions of the green sheet 40, so that the green sheet 40 moves the paste 5 toward the screen 26.
There is no transfer due to the adhesive force of 0. Moreover,
Since the pressing members 36a and 36b are made of silicone rubber with high elasticity, the green sheet 40
There is no need to deform the ends.

FIG. 3 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, a plate frame holder 70 is provided to hold the plate frame 25. This plate frame holder 7
Elongated holes 72a and 72b are formed in a pair of frame members 71a and 71b facing each other, respectively, and the pressing member 3
Angle members 74a to 74d that lock 6a and 36b are screwed together and held using bolts 76a and 76b.

In this way, as in the previous embodiment, any size of plate frame can be used. Of course,
Needless to say, the plate frame holder 70 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 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 substrate and 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 a screen printing machine according to the present invention, and FIG. 1b is a first
A longitudinal sectional view of the main parts of the screen printing machine shown in Figure a,
FIGS. 2a to 2d are schematic longitudinal sectional views 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 FIG. 4a , b are schematic vertical sectional views showing the operating state of a screen printing machine according to the prior art. 20... Screen printing machine, 22... Printing stand, 23
...Prepress department, 25...Print frame, 26...Screen, 36
a, 36b...pressing member, 40...green sheet,
50...Paste, 60...Squeegee, 70...Form frame holder, 71a, 71b...Frame member, 72a, 72b
...Long hole, 74a-74d...Angle member, 76
a, 76d...Bolt.

Claims (1)

[Scope of Claims] 1. A printing table on which a green sheet is placed, a support member arranged above the printing table and supporting a plate frame on which a screen for pattern printing is stretched, and a support member arranged on the lower side of the plate frame. a pressing member for holding down an end of the green sheet made of an elastic material, and supported by the supporting member so that the pressing member can be displaced according to the size of the green sheet. A screen printing machine characterized by: 2. The screen printing machine according to claim 1,
Screen printing characterized in that the support members are two columnar members provided along the respective outer edges of opposing frame members parallel to the moving direction of the squeegee of the plate frame. Machine. 3. The screen printing machine according to claim 1,
The support member is a plate frame holder located at the upper part of the plate making section, and the plate frame holder is capable of displacing the pressing member through elongated holes provided in a pair of opposing frame members of the plate frame holder. A screen printing machine characterized by holding.