KR20090064306A - Screen printer - Google Patents

Abstract

A screen printing machine is provided to improve adhesiveness of a substrate and a mask in printing, and to print a pattern precisely without positional deviation of the pattern of a fine pitch due to deformation of the mask. A method for operating a screen printing machine comprises the followings steps of: contacting a mask(20) with a surface of a substrate absorbed on a printing table(10); pushing solder paste or flux with a squeegee in an opening installed at a mask surface; performing a transcription process; installing a holding member of the mask surface; moving the squeeze in a state maintaining the mask; and supplying the solder paste or the flux into an mask opening.

Description

Screen Printing Machine {SCREEN PRINTER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen printing apparatus, and more particularly, to a screen printing apparatus that is optimal for pattern formation of openings of fine pitch.

In the conventional screen printing apparatus, as described in Patent Literature 1, a printing machine having a good plate separation method has been developed at the time of printing and at the time of printing the solder paste with a squeegee.

[Patent Document 1]

Japanese Patent Application Laid-Open No. 2007-21882

In the above prior art, it is necessary to provide a certain gap between the screen and the substrate, and the solder paste is printed on the substrate by pressing the mask onto the substrate with a squeegee. However, in recent years, the printing pattern to be printed is miniaturized and the demand for printing a large substrate is increasing. In the case of printing a fine pattern, as a problem of the prior art, a position shift occurs due to the elongation of the mask due to the frictional resistance between the squeegee and the mask when the mask is pressed onto the substrate with a squeegee and moved on the mask surface. There is a case. For this reason, it is necessary to improve the adhesiveness of the board | substrate which is a printing object, and a mask, and to print in the state without position shift. Therefore, unlike the related art, it is necessary to improve the adhesiveness between the substrate and the mask and to prevent the extra paste from adhering to the substrate even when the plate is separated. Moreover, the printing table which holds a board | substrate is restrict | limited to the magnitude | size which can hold | maintain a board | substrate for size reduction of an apparatus. In general, the size of the mask used for printing is to use a large mask for the substrate area, so that the mask itself is deformed because the mask is pushed out of the substrate and the portion thereof is maintained without support. In some cases, it may adversely affect printing.

Accordingly, an object of the present invention is to provide a screen printing apparatus which can improve the adhesion between the substrate and the mask during printing, and can easily perform plate separation, and can print on a large substrate with a fine pitch. Is in.

In the screen printing machine which pushes solder paste or flux and transfers to a board | substrate surface, the mask surface holding member which maintains the mask surface of the board | substrate periphery held by the printing table at the board | substrate side is provided, and a mask is provided with a board surface and a mask surface holding member The squeegee is moved on the mask surface in the state of holding, so that solder paste or flux is supplied to the mask opening.

In addition, by providing the adsorption mechanism on the mask surface holding member, the mask can be reliably held by attracting and holding the mask around the substrate surface.

Since the deformation of the mask can be prevented, it is possible to reliably print even a fine pitch pattern without causing misalignment. In addition, since the mask surface is always in contact with the substrate and the mask surface support member during printing, the solder paste or flux to the mask back surface does not drift, and a stable printing shape can be realized. For this reason, although the back surface of the mask was normally needed every time a plurality of printings have been performed, the number of times of cleaning can be reduced, and the productivity of printing can be improved.

In addition, since the mask surface can be reliably held, drift of the solder paste or the flux to the back surface of the mask can be prevented as described in the above embodiment. In addition, by firmly fixing the mask around the substrate, the adhesion between the mask and the substrate at the boundary portion around the substrate is improved. As a result, the transfer shape and transfer amount of the solder paste at the print start and end portions and the center portion of the substrate can be made uniform.

The outline of the whole structure of a screen printing apparatus is shown in FIG.

The plate frame holder which is not shown in figure is provided in the main body frame, and the mask frame which attached the screen 21 which has a printing pattern as an opening part is comprised in the plate frame holder. A squeegee head 2 is disposed above the mask 20, and a squeegee 3 is attached to the squeegee head 2. The squeegee head 2 is movable in the horizontal direction by the squeegee moving mechanism 6, and the squeegee 3 can be moved in the vertical direction by the squeegee lifting mechanism 4. Below the mask 20, the printing table 10 which mounts and hold | maintains the board | substrate 21 which is a printing object so as to face a mask is provided. This printing table 10 receives the XYθ table 11 which moves the board | substrate 21 in a horizontal direction, and performs alignment with the mask 20, and receives the board | substrate 21 from the receiving conveyor 26, and also the board | substrate. A table elevating mechanism 12 is provided for bringing (21) close to or in contact with the mask 20 surface. The substrate receiving conveyor 26 is provided in the upper surface of the printing table 10, the board | substrate 21 carried in by the board | substrate loading conveyor 25 is received on the printing table 10, and a board is carried out when printing is complete | finished. The substrate 21 is discharged to the conveyor 27.

In the fully automatic screen printing apparatus, the mask 20 and the substrate 21 are automatically aligned. That is, the CCD camera 15 picks up the alignment mark provided on each of the mask 20 and the board | substrate 21, image-processes, calculates the position shift amount, and corrects the shift amount. The positioning is performed by driving the XYθ table 11 based on the command from the control unit 35.

In addition, the printer control unit 30 including the print control unit 36 for driving each unit and the image input unit 37 for processing the image signal from the CCD camera 15 is provided inside the main body frame of the printer. A data input unit 50 for re-input of data, a change in printing conditions, and the like, and a display unit 40 for monitoring the printing status or the like and introduced recognition marks are disposed outside the printing press.

The board | substrate 21 to which solder paste or a flux is printed is supplied to the board | substrate receiving conveyor 26 by the board | substrate loading conveyor 25, and is fixed to the predetermined position on the printing table 10. FIG. After fixing the board | substrate 21 to the printing table 10, the CCD camera 15 is moved to the board | substrate mark position previously registered. Subsequently, the CCD camera 15 picks up the position recognition mark (not shown) provided in the board | substrate 21 and the mask 20, and transmits it to the printer control part 30. FIG. In the image input unit 37 in the control unit, the positional shift amount between the mask 20 and the substrate 21 is obtained from the image data. Based on the result, the printer control unit 30 sends a drive signal from the XYθ table control unit 35 to the XYθ table 11 and operates the XYθ table 11 based on the signal to operate the substrate on the mask 20. Correct the position of (21) and align it. After completion of the alignment operation, the CCD camera 15 retracts the predetermined amount to a position where it does not interfere with the print table 10. After completion of camera retraction, the print table 10 is raised to bring the substrate 21 and the mask 20 into contact with each other. Thereafter, the squeegee lifting cylinder 4 lowers the squeegee 3 until it comes into contact with the mask 20 surface, and the solder paste or flux supplied on the mask by the movement of the squeegee head 2 is removed. The opening of the mask 20 is filled and transferred to the substrate. The squeegee 3 ascends after a predetermined distance stroke in the horizontal direction. Then, the printing table 10 is lowered, the mask 20 and the substrate 21 are separated, and the solder paste or flux filled in the opening of the mask 20 is transferred to the substrate 21.

Subsequently, the substrate 21 on which the solder paste or the flux is printed is sent to the next step via the substrate transport conveyor 27.

In addition, two or more recognition mark alignment marks are provided on the substrate 21 and the mask 20 at relatively the same portions, and each of the marks is placed on a special CCD camera 15 having two views in the vertical direction. By this, the mark of the mask 20 is recognized from the bottom, the mark of the substrate 21 is recognized from the top, the position coordinates of the entire mark of the predetermined part are read out, and the mark of the substrate 21 with respect to the mask 20 is read. The displacement amount is calculated and corrected, and the substrate 21 is positioned with respect to the mask 20.

In the printer control unit 30 shown in FIG. 1B, the arbitrary pattern picked up by the CCD camera 15 is introduced from the image input unit 37, even if a similar pattern exists around the arbitrary pattern. The correlation value between the model prepared in advance and the arbitrary pattern picked up by the CCD camera 15 is calculated by the correlation value calculation unit 31. On the basis of the correlation value obtained by the correlation value calculation unit 31, the shape estimation unit 32 estimates the shape of the model. The estimated shape is stored and stored as a plurality of temporary reference patterns. And the pattern position coordinate calculating part 33 compares with the distance between target reference patterns, and obtains the shape dimension in the dimension calculating part 34, and registers the mark of the combination with the smallest difference as a reference pattern in the dictionary 38 as a reference pattern. Means are provided.

In addition, the printer controller 30 includes a print controller 36 for controlling the operation of the squeegee head 2 and the like.

Next, an embodiment of the mask support will be described with reference to FIG. 2. An example of the structure of a printing table part is shown in FIG. As shown in the figure, a mask surface support member for supporting the mask 20 surface separately from the print table 10 is provided at the periphery of the substrate 21, which is a printing object mounted on the print table 10. As for this mask surface support member, the mask surface support member 61 of one side is fixed to the base 19 which supports the printing table 10, and the mask surface support member 60 of the other side is And a structure capable of moving in the substrate direction (arrow 41 direction). That is, the ball screw 17 is provided so that the leg part of the movable side mask surface support member 60 may be similarly moved by the drive motor 16 provided in the leg part of the mask surface support member 61 on the fixed side. Moreover, the ball bearing which is not shown in figure is provided so that the leg part of the movable side mask surface support member 60 can slide on the linear rail 45 provided in the base part 46. As shown in FIG. By rotating the ball screw 17 by driving the motor 16 to the fixed side mask surface support member 61, the movable side mask surface support member 60 is pressed against the side of the other side of the substrate 21. It is. Moreover, the edge part of the fixed side mask surface support member 61 is in contact with the side surface of one side of the board | substrate 21, and it is set as the structure which can be positioned. The part which contacts the mask surface of this mask surface support member has a predetermined area. In addition, the printing table 10 is configured to fix the substrate 21 to the table surface by supplying a negative pressure (arrow 42).

In this manner, the mask surface is not only in contact with the substrate surface, but is also supported by the upper surface of the mask surface support members 60 and 61 so as to be supported around the mask surface, so that the mask 20 is the substrate when the squeegee 3 is moved. Not only the (21) surface but also the mask surface supporting members 60 and 61 are supported, and the deformation of the mask 20 can be prevented. For this reason, it is possible to reliably print even a fine pitch pattern without causing misalignment. In addition, since the mask surface is always in contact with the substrate and the mask surface support member during printing, the solder paste or flux to the back surface of the mask does not drift, and stable plate separation can be realized. For this reason, although the back surface of the mask was normally needed every time a plurality of printings have been performed, the number of times of cleaning can be reduced, and the productivity of printing can be improved.

Next, another embodiment will be described with reference to FIG. 3. 3 is different from FIG. 2 in that a suction adsorption mechanism including a plurality of suction holes is provided at a portion of the mask surface support member in contact with the mask. Also in FIG. 2, the printing table 10 has a structure in which a plurality of negative pressure supply holes (adsorption holes) are provided on the surface of the printing table 10 to fix the substrate 21. Also in this embodiment, a negative pressure supply hole is provided on the surface of the printing table 10, and a plurality of negative pressure supply holes are provided on the surface in contact with the mask 21 surface of the mask surface support members 60 and 61, and By supplying the negative pressure, the mask 21 is reliably held. As a result, since the mask 21 can be held more reliably than in the above-described embodiment, as described in the above-described embodiment, drift of the solder paste or the flux to the back surface of the mask can be prevented. In addition, by firmly fixing the mask around the substrate, the adhesion between the mask and the substrate at the boundary portion around the substrate is improved. As a result, the transfer shape and transfer amount of the solder paste at the print start and end portions and the center portion of the substrate can be made uniform.

In FIG. 3, the mask surface holding member is suction-adsorbed. However, when the mask to be used is made of magnetic metal, an electromagnet is disposed at the part in contact with the mask of the mask surface holding member to hold the mask surface. At this time, the electromagnet may be operated to maintain the adsorption.

1 is a diagram showing the overall configuration of a screen printing apparatus;

2 illustrates an embodiment of mask support;

3 shows another embodiment of mask support.

※ Explanation of code for main part of drawing

1: screen printing machine 2: squeegee head

3: squeegee 4: squeegee lifting mechanism

6: squeegee moving mechanism

60: movable side mask surface support member

61: fixed side mask surface holding member

Claims (4)

In the screen printing machine which contacts a board | substrate adsorbed-held on a printing table, pushes a solder paste or flux by the squeegee in the opening provided in the mask surface, and transfers to a board | substrate surface, The mask surface holding member for holding the mask surface on the substrate periphery held by the printing table on the substrate side is provided, and the squeegee is moved on the mask surface while the mask is held by the substrate surface and the mask surface holding member to the mask opening. A screen printing machine characterized in that it is configured to supply solder paste or flux. The method of claim 1, And said mask surface holding member is a mask surface holding member fixed at one end of the substrate, and the mask surface holding member movable at the other end of the substrate. The method of claim 2, A screen printing machine comprising: a plurality of adsorption holes provided on a surface of the mask surface holding member that is in contact with the mask, and configured to adsorb and hold the mask by supplying negative pressure to the adsorption holes. The method of claim 2, And the mask is made of a magnetic metal, and an electromagnet is disposed at a portion of the mask surface holding member in contact with the mask to hold and adsorb and hold the mask.

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