JP3622709B2 - Screen printing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screen printing apparatus that prints paste such as cream solder or conductive paste on a substrate.
[0002]
[Prior art]
In an electronic component mounting process, screen printing is used as a method for printing paste such as cream solder or conductive paste on a substrate. In this method, a mask plate in which pattern holes are formed according to a printing target portion is set on a substrate, and paste is printed on the substrate through the pattern holes of the mask plate by squeezing.
[0003]
As a screen printing squeezing method, a method using a sealed squeegee head is known. Unlike normal screen printing, this method uses a squeegee head in which the paste is stored, instead of supplying the paste directly onto the mask plate. In this method, the paste contact surface provided on the lower surface of the squeegee head is in contact with the mask plate, and the squeegee head is moved to sequentially fill the pattern holes of the mask plate with the paste via the paste contact surface. Let
[0004]
[Problems to be solved by the invention]
However, screen printing using the above-described conventional sealed squeegee head has the following problems. In squeegeeing, the paste is filled into the pattern holes while pushing the paste in the squeegeeing direction on the mask plate surface with a squeegee. In this filling operation, fluidity in the rotational direction is imparted to the paste by the progress of the squeegee. The paste is caused to enter the pattern hole using the rolling action.
[0005]
However, in a sealed squeegee head, since the paste is contained in a large amount in the printing space where the paste is brought into contact with the mask plate, the aforementioned rolling is unlikely to occur and it is difficult to ensure good filling properties. There was a problem that there was.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a screen printing apparatus that can ensure good filling in a sealed squeegee head.
[0008]
[Means for Solving the Problems]
The screen printing apparatus according to claim 1 , wherein the screen printing apparatus prints a paste on a substrate through a pattern hole of the mask plate by moving the squeegee head on the mask plate, and the squeegee head is applied to the mask plate. In contrast, each of the squeegee heads is provided on the lower surface for containing the paste. A printing space that is brought into contact with the surface of the mask plate through the opening, and two opposing sliding contact members that form front and rear wall surfaces in the squeezing direction of the printing space and whose lower ends are in sliding contact with the surface of the mask plate; On the mask plate, paste is placed between the two sliding members and flows in the printing space. And a flow control plate to impart the direction of flow component directed in the flow control plate is rotatably supported on a horizontal rotational axis in the printing space, the rotation by the flow of the squeezing direction of said paste By rotationally displacing around the axis, the filling angle of the flow control plate with respect to the upper surface of the mask plate changes.
[0009]
3. The screen printing apparatus according to claim 2, wherein the squeegee head is moved on the mask plate to print the paste on the substrate through the pattern hole of the mask plate, and the squeegee head is applied to the mask plate. In contrast, each of the squeegee heads is provided on the lower surface for containing the paste. A printing space that is brought into contact with the surface of the mask plate through the opening, and two opposing sliding contact members that form front and rear wall surfaces in the squeezing direction of the printing space and whose lower ends are in sliding contact with the surface of the mask plate; On the mask plate, paste is placed between the two sliding members and flows in the printing space. And a flow control plate to impart the direction of flow component directed in the flow control plate is a flexible plate member supported to the upper end by a horizontal fixed support shaft in the printing space, printing of the paste When the plate member is bent by the flow in the direction, the filling angle of the flow control plate with respect to the upper surface of the mask plate changes.
[0010]
According to the present invention, by providing a flow control plate that applies a flow component in the direction toward the upper surface of the mask plate to the paste flowing in the printing space, the rolling effect is superimposed to improve the filling property of the paste into the pattern hole. Can be made.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a screen printing apparatus according to an embodiment of the present invention, FIG. 2 is a side view of the screen printing apparatus according to an embodiment of the present invention, and FIGS. 5 is a partial sectional view of the squeegee head of the screen printing apparatus, FIG. 5 is a diagram for explaining the operation of the squeegee head in screen printing according to an embodiment of the present invention, and FIG. 6 is a flow control plate of the screen printing apparatus according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of the flow control plate of the screen printing apparatus according to the embodiment of the present invention.
[0012]
First, the structure of the screen printing apparatus will be described with reference to FIGS. 1 and 2, the substrate positioning unit 1 is configured by disposing a substrate holding unit 2 on a moving table (not shown). The substrate 3 to be screen-printed is held by a clamper 4 of the substrate holder 2, and the substrate 3 held by the substrate holder 2 is positioned in the horizontal direction and the vertical direction by driving the moving table.
[0013]
A screen mask 10 is disposed above the positioning unit 1. The screen mask 10 is configured by mounting a mask plate 12 on a holder 11, and a pattern hole 12 a corresponding to a printing portion of a substrate 3 to be printed is opened in the mask plate 12.
[0014]
A squeegee head 13 is disposed on the screen mask 10 so as to be movable up and down by a head lifting unit 20. The head lifting / lowering unit 20 includes a cylinder 22 erected on a base member 21. The squeegee head 13 is coupled to the lower end portion of the rod 22 a of the cylinder 22 via the coupling member 15.
[0015]
By driving the cylinder 22, the squeegee head 13 moves up and down relative to the mask plate 12 and presses the squeegee head 13 against the mask plate 12. The head elevating unit 20 is an elevating unit that elevates and lowers the squeegee head 13 with respect to the screen mask 10. The cylinder 22 is a pressing unit that presses the squeegee head 13 against the mask plate 12.
[0016]
Sliders 23 are fixed to both ends of the lower surface of the base member 21 of the head elevating unit 20, and the sliders 23 are slidably fitted to guide rails 24 disposed on the upper surface of the frame 25. A nut member 26 is coupled to the lower surface of the base member 21, and a feed screw 27 screwed into the nut member 26 is driven to rotate by a motor 28.
[0017]
By driving the motor 28, the base member 21 moves horizontally, and thus the squeegee head 13 coupled to the head lifting / lowering unit 20 also moves horizontally. By driving the motor 28 with the squeegee head 13 lowered, the squeegee head 13 moves horizontally on the mask plate 12. That is, the motor 28, the feed screw 27, and the nut member 26 serve as a horizontal movement unit that horizontally moves the squeegee head 13 on the mask plate 12.
[0018]
Below the squeegee head 13, there is provided a printing unit 14 that contacts the surface of the mask plate 12 and fills the pattern holes 12 a with cream solder 5 that is a paste. The structure of the printing unit 14 will be described with reference to FIG. In FIG. 3, reference numeral 30 denotes a main body, which is a block-like member that is elongated in the width direction of the mask plate 12. The length of the main body 30 is set so as to cover the width of the substrate 3 to be printed as shown in FIG. The main body 30 is formed with a recess 30a in which the cartridge 31 storing the cream solder 5 is detachably mounted.
[0019]
The cartridge 31 is a cream solder storage part (paste storage part) in which a predetermined amount of cream solder is stored in advance, and is attached to the main body 30 during printing. A pressurizing plate 33 that pressurizes the internal cream solder 5 is fitted into the opening on the upper surface of the cartridge 31. The pressure plate 33 is in contact with a push-down member 32 coupled to the rod 16 a of the cylinder 16 disposed above, and the pressure plate 33 moves up and down within the cartridge 31 by the push-down member 32 by driving the cylinder 16. It is like that.
[0020]
The bottom surface of the cartridge 31 is a cream solder extrusion plate 31a, and the extrusion plate 31a has a large number of openings 31b. By pressing the pressure plate 33 downward by the cylinder 16, the cream solder 5 in the cartridge 31 is pressurized and pushed downward through the opening 31b of the extrusion plate 31a. The cylinder 16 and the pressure plate 33 serve as paste pressing means for pressing the cream solder 5 that is a paste.
[0021]
Next, the squeezing unit 36 and the print space 35 will be described. The squeezing part 36 is composed of four-direction wall surfaces that surround the periphery below the main body part 30, and a printing space 35 is formed inside these wall surfaces. Two opposing sliding members 37A and 37B that form front and rear wall surfaces of the printing space 35 are disposed at both ends of the squeezing portion 36 in the squeezing direction (arrow a direction). During the printing operation, the printing space 35 accommodates the pressurized cream solder 5, and the cream solder 5 is applied to the mask plate 12 via the lower surface of the printing space 35, that is, the opening between the two sliding contact members 37 </ b> A and 37 </ b> B. Touch the surface.
[0022]
An elongated flow control plate 40 that is continuous over the entire width of the main body 30 is disposed in the printing space 35 between the two sliding members 37A and 37B. As will be described later, the flow control plate 40 imparts a flow component in the direction toward the upper surface of the mask plate 12 to the cream solder 5 that flows in the printing space 35 during squeezing. FIG. 3B shows the shape of the flow control plate 40 in the longitudinal direction, and the flow control plate 40 is supported so as to be rotatable around a rotation shaft 40 a supported in the horizontal direction in the printing space 35.
[0023]
In the squeezing operation, the flow control plate 40 is rotationally displaced about the rotation axis 40a by the flow of the cream solder 5 in the squeezing direction. Thus, as described below, the filling angle of the flow control plate 40 with respect to the upper surface of the mask plate 12 (the angle between the lower surface of the flow control plate 40 on the squeezing direction side and the upper surface of the mask plate 12 (shown in FIGS. 4 and 5). The angles α, β)) change.
[0024]
A screen printing operation by the squeegee head 13 will be described. When the squeegee head 13 is moved in the direction of arrow a in a state where the cream solder 5 is pushed and filled from above into the print space 35 as shown in FIG. 4A, the cream solder 5 in the print space 35 is A drag force in a direction opposite to the squeezing direction is applied to the flow control plate 40, and the flow control plate 40 is rotationally displaced about the rotation axis 40a. As a result, the angle of the flow control plate 40 with respect to the upper surface of the mask plate 12 becomes an acute filling angle α. In this state, the squeegee head 13 moves in the direction of arrow a, so that the cream solder 5 moves toward the upper surface of the mask plate 12. Flow in the direction of arrow b is provided.
[0025]
When the squeegee head 13 further moves, among the cream solder 5 in the printing space 35, a flow in the direction of arrow c is similarly given to the cream solder 5 by the filling member 38 of the sliding contact member 37A on the rear side in the squeegeeing direction. . As a result, in the process of moving the squeegee head 13, the rolling effect acts on one pattern hole 12a of the mask plate 12 in an overlapping manner, and the filling performance of the cream solder 5 into the pattern hole 12a is improved. Is possible.
[0026]
FIG. 5 shows a case where the squeegee head 13 is moved in the direction of the arrow d by reversing the squeezing direction. In this case as well, the rolling effect acts in an overlapping manner by the flow control plate 40 that is rotationally displaced at the filling angle β with respect to one pattern hole 12a and the filling member 38 of the sliding contact member 37B.
[0027]
In addition, as shown in FIG. 6, a plurality of comb-like protrusions 40 b protruding upward may be provided on the upper side of the rotating shaft 40 a, whereby the cream solder 5 protrudes in the printing space 35. The cream solder 5 is displaced in the directions of the arrows e and f perpendicular to the directions of the arrows c and d when passing through the gap of the portion 40b and flows in the directions of the arrows c and d, thereby reducing the viscosity of the cream solder 5. Effect can be obtained.
[0028]
Note that a fixed plate member as shown in FIG. 7 may be used as the flow control plate. That is, as shown in FIG. 7A, a fixed support shaft 40'a is provided in the printing space 35 instead of the rotation shaft 40a, and the flexible plate member 40 'is thin and easily bent on the fixed support shaft 40'a. Support the top edge. When the cream solder 5 flows by squeezing in the printing space 35, the plate member 40 'receives a drag force in the direction opposite to the squeezing direction from the cream solder 5 as shown in FIG. Due to this, bending deformation occurs according to the squeezing direction. This also changes the filling angle θ between the plate member 40 ′ and the mask plate 12, and can impart a fluid component in the direction toward the surface of the mask plate 12 to the cream solder 5 as described above.
[0029]
【The invention's effect】
According to the present invention, the flow control plate that applies the flow component in the direction toward the upper surface of the mask plate to the paste flowing in the printing space is provided, so that the rolling effect is superimposed to improve the filling property of the paste into the pattern hole. Can be made.
[Brief description of the drawings]
FIG. 1 is a front view of a screen printing apparatus according to an embodiment of the present invention. FIG. 2 is a side view of a screen printing apparatus according to an embodiment of the present invention. FIG. 4 is a partial sectional view of a squeegee head of a screen printing apparatus according to an embodiment of the present invention. FIG. 5 is an explanation of the operation of the squeegee head in screen printing according to an embodiment of the present invention. FIG. 6 is a perspective view of a flow control plate of a screen printing apparatus according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a flow control plate of a screen printing apparatus according to an embodiment of the present invention.
3 Substrate 5 Cream solder 12 Mask plate 12a Pattern hole 13 Squeegee head 20 Head elevating part 35 Printing space 36 Squeezing part 37A, 37B Sliding member 40 Flow control plate 40a Rotating shaft

Claims (2)

A screen printing apparatus for printing a paste on a substrate through a pattern hole of a mask plate by moving the squeegee head on the mask plate, and moving the squeegee head in a horizontal direction with respect to the mask plate to move up and down Horizontal movement means, lifting and lowering means, and pressing means for pressing the squeegee head against the mask plate. The squeegee head accommodates the paste on the surface of the mask plate through an opening formed in the lower surface. A printing space to be contacted, two opposed sliding members that form front and rear wall surfaces in the squeezing direction of the printing space, and whose lower end portions are in sliding contact with the surface of the mask plate, and disposed between the two sliding contact members Is applied to the paste flowing in the printing space, and a flow component in a direction toward the upper surface of the mask plate. And a control plate, the flow control plate, the rotatably supported within a horizontal rotational axis printing space, by rotational displacement to the rotational axis by the flow of the squeezing direction of the paste, the mask features and to Luz screen printing apparatus that filling angles of the flow control plate with respect to the upper surface of the plate is changed. A screen printing apparatus for printing a paste on a substrate through a pattern hole of a mask plate by moving the squeegee head on the mask plate, and moving the squeegee head in a horizontal direction with respect to the mask plate to move up and down Horizontal movement means, lifting and lowering means, and pressing means for pressing the squeegee head against the mask plate. The squeegee head accommodates the paste on the surface of the mask plate through an opening formed in the lower surface. A printing space to be contacted, two opposed sliding members that form front and rear wall surfaces in the squeezing direction of the printing space, and whose lower end portions are in sliding contact with the surface of the mask plate, and disposed between the two sliding contact members Is applied to the paste flowing in the printing space, and a flow component in a direction toward the upper surface of the mask plate. And a control plate, the flow control plate is a flexible plate member supported to the upper end by a horizontal fixed support shaft in the printing space, wherein the plate member is bent by the flow of the printing direction of the paste it allows features and to Luz screen printing apparatus that filling angles of the flow control plate with respect to the upper surface of the mask plate is changed.

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