JP4375262B2 - Screen printing device - Google Patents

Description

  The present invention relates to a screen printing apparatus that prints paste such as cream solder or conductive paste on a substrate.

  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 part (generally, an electrode of a circuit pattern) is set on the substrate, and paste is applied to the substrate through the pattern hole of the mask plate by squeezing. Is to be printed.

  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 is pushed into the pattern hole of the mask plate by pressing the paste in the squeegee head from above with the paste contact surface provided on the lower surface of the squeegee head in contact with the mask plate. Then, by sliding two front and rear sliding portions (squeegees) provided on the squeegee head on the mask plate, each pattern hole is sequentially filled with paste.

  However, the paste storage container used in the above-described conventional sealed squeegee head is a container manufactured by molding a resin into an elongated box shape, and thus has a high running cost, and remains unused inside. This is a factor that increases the cost of screen printing, such as generation of residual paste that is discarded as it is and waste of paste.

  Therefore, the present applicant has previously proposed a screen printing apparatus capable of supplying paste at a low cost (Patent Document 1). This is a replaceable cartridge by forming a paste storage container that stores paste in the squeegee head into a container shape with a flexible resin film open at the bottom, and this cartridge can be freely attached to and detached from the container holder. In this way, the paste container can be manufactured at a low cost.

  FIG. 10 is a cross-sectional view of a squeegee head of a conventional screen printing apparatus, and relates to Patent Document 1. Inside the container holding portion 101 of the squeegee head 100, an exchangeable paste storage container 102 for storing the paste P is detachably held. The paste container 102 is made of the above-described flexible resin film, and its upper surface is pressed downward by a pressure plate 103.

  A receiving part 104 is provided opposite to the container holding part 101, and the end parts of the two upper and lower perforated plates 105, 106 are sandwiched from above and below by both 101, 104. The receiving unit 104 is grounded to the upper surface of the mask plate 108 superimposed on the substrate 107, and the inside is a printing space 109. A horizontal shaft 110 as a rectifying member is disposed inside the lower receiving portion 104 with both ends thereof held by the lower receiving portion 104. Reference numeral 111 denotes a pattern hole opened in the mask plate 108.

By pressurizing the paste container 102 from above with the pressure plate 103, the paste P inside the paste container 102 descends from the holes 112, 113 formed on the entire surface of the porous plates 105, 106 to the lower print space 109. When the squeegee head 100 flows and slides in a direction perpendicular to the paper surface, the paste P passes through the pattern 111 and the substrate 107 by two slidable contact portions (squeegee) (not shown) provided before and after the squeegee head 100. Printed on.
JP 2004-17515 A

  In FIG. 10, the lateral dimension L of the substrate 107 varies in size. In the present invention, the sliding (squeegeeing) direction of the sliding contact portion (squeegee) is defined as the front-rear direction (Y direction), and the direction orthogonal thereto is defined as the lateral direction (X direction). FIG. 10 shows a case where screen printing is performed on a substrate 107 having a slightly short lateral dimension L.

  In this case, free portions D of the mask plate 108 where the substrate 107 does not contact are generated on both sides of the mask plate 108. Since the substrate 107 does not come into contact with the free portion D, the mask plate 108 hangs down slightly in the free portion D as shown in the figure. As a result, a slight gap G is generated between the lower receiving portion 104 on the side of the squeegee head 100 and the mask plate 108, and paste leakage occurs on the mask plate 108 from here. The paste P leaked onto the mask plate 108 unnecessarily stains the mask plate 108 and obstructs screen printing. The gap G becomes larger as the lateral dimension L of the substrate 107 is smaller, which adversely affects screen printing.

  Accordingly, the present invention eliminates the above-described conventional problems, ensures the sealing of the printing space regardless of the horizontal dimension of the substrate, and eliminates paste leakage to the side of the squeegee head. The purpose is to provide.

Screen printing apparatus according to claim 1 wherein the paste comprises a squeegee head, a horizontally moving means for moving horizontally the squeegee head with respect to the mask plate, and a lifting means for raising and lowering the squeegee head with respect to the mask plate A paste screen printing apparatus, wherein the squeegee head includes a paste container for storing the paste, a container holding unit for detachably holding the paste container, and a pressure for pressing the paste in the paste container from above. Means, a printing space for storing the paste that has been pressed by the pressing means and flowing downward, and brought into contact with the surface of the mask plate through an opening formed in the lower surface, and between the paste container and the printing space disposed of at the bottom of the paste passing member in accordance with the paste passing member interposed, the lateral dimension of the substrate size to Yes and the partition member a lateral position is set in the printing space, and said squeezing direction of the front and rear walls of the printing space to form the upper surface of the mask plate before and after facing sliding contact with the two sliding portions Te The paste container is made of a flexible film-like material, and a plurality of container parts having openings at the bottom are formed in the plate body with a pitch in the lateral direction, and a connecting part between the container part and the projecting part. The horizontal dimension of the paste container is adjusted to the horizontal dimension of the printing space by cutting the number of the container parts, and the partition member is positioned immediately above both sides of the substrate .

  The paste screen printing apparatus according to claim 2 is the paste screen printing apparatus according to claim 1, wherein the container portion is a trapezoidal box portion that spreads downward toward the bottom.

The claims 3 paste screen printing apparatus according to a screen printing apparatus according to claim 1 or 2 wherein the paste is provided a horizontal shaft below the paste passing member, transverse the partition member to the shaft Was slidably provided.

5. The paste screen printing apparatus according to claim 4, wherein the paste screen printing apparatus according to claim 3 is provided with a receiving portion facing the container holding portion below the container holding portion, and both ends of the shaft. The part was held by this receiving part.

  According to the present invention, the connecting portion of the paste container is cut according to the size of the horizontal dimension of the substrate to reduce the number of container portions, and the horizontal position of the partition member is adjusted and set. By defining the width of the printing space in the lateral direction, it is possible to eliminate paste leakage to the side of the squeegee head caused by the downward sag of the mask plate.

  Next, embodiments of the present invention will be described with reference to the drawings. 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 FIG. 3 is a screen printing apparatus according to an embodiment of the present invention. 4 is a front sectional view of the squeegee head, FIG. 4 is an internal plan view of the squeegee head of the screen printing apparatus in one embodiment of the present invention, and FIG. 5A is a perspective view of a paste container in one embodiment of the present invention. FIG. 5 (b) is an upside down perspective view of the paste container in one embodiment of the present invention, FIG. 6 is an explanatory view of a partition member of the squeegee head of the screen printing apparatus in one embodiment of the present invention, and FIG. It is a top view of the perforated plate of the screen printing apparatus in one embodiment of the invention.

  First, the overall structure of the screen printing apparatus will be described with reference to FIGS. 1 and 2, the substrate positioning unit 1 includes a Y table 2, an X table 3, a θ table 4, a backup unit 5, and the like stacked in order from the bottom. The backup table 5 includes an entire lifting motor 51 of the backup unit 5, a lifting motor 53 of the backup plate 52, and the like, and supports the substrate 6 from below by support pins (not shown) erected on the backup plate 52. To do. The board | substrate 6 is carried in to the guide rail part 8 above the positioning part 1 by the carrying-in part 7, and is positioned in a predetermined position there by the positioning part 1, and screen printing of the paste is made on the upper surface. The substrate 6 for which printing has been completed is carried out to the next step by the carry-out unit 9.

  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 (see FIG. 3) corresponding to a printing portion of a substrate 6 to be printed is opened in the mask plate 12.

  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 long plate-like base 21, and a squeegee head 13 is coupled to a lower end portion of a rod 22 a of the cylinder 22 via a plate-shaped coupling member 15. Has been. The squeegee head 13 moves up and down with respect to the mask plate 12 by driving the cylinder 22 to project and retract the rod 22a. Therefore, the head lifting / lowering unit 20 is a lifting / lowering unit that lifts / lowers the squeegee head 13 relative to the mask plate 12.

  In FIG. 1, sliders 23 are mounted on the lower surfaces of both ends of the base portion 21 of the head elevating unit 20, and the sliders 23 slide on guide rails 24 that are horizontally disposed in the Y direction on the upper surface of the standing frame 25. Fits freely. Further, a nut member 26 is coupled to the lower surface of the side portion of the base portion 21, and a feed screw 27 screwed into the nut 26 is rotationally driven by a motor 28 (see also FIG. 2).

  In FIG. 2, by driving the motor 28, the base 21 moves horizontally in the Y direction (front-rear direction). Therefore, by driving the motor 28 with the squeegee head 13 lowered, the squeegee head 13 moves horizontally on the mask plate 12 in the Y direction. That is, the motor 28, the feed screw 27, and the nut 26 serve as a horizontal movement unit that horizontally moves the squeegee head 13 on the mask plate 12 in the X direction.

  1 and 2, the squeegee head 13 is provided with a printing unit 14 that contacts the surface of the mask plate 12 and fills the pattern holes 12a with cream solder P that is a paste. The printing unit 14 is divided into an upper part 14A and a lower part 14B, and the upper part 14A and the lower part 14B are provided with a main body upper part 30A and a main body lower part 30B which are frame-like members elongated in the horizontal direction.

  The length dimension (lateral dimension) of the main body upper part 30A and the main body lower part 30B is set to a length that covers the width dimension of the large substrate 6. The main body upper part 30A and the main body lower part 30B are coupled to each other via a hinge part (not shown) in the same manner as in Patent Document 1, so that the main body upper part 30A and the main body lower part 30B can be rotated or separated around the hinge part. Thus, it is possible to open the two.

  As shown in FIGS. 1 to 3, a cartridge 31 as a paste container in which cream solder P is stored is replaceably mounted and held in the main body upper part 30 </ b> A. The cartridge 31 is an exchangeable paste container formed of a film material made of a flexible resin, and has a shape in which the lower part is opened in the mounting posture. In FIG. 3, a cartridge 31 is supported from below by perforated plates 32, 33 as paste passage plates having a large number of apertures 32a, 33a, and is detachably housed and held inside the upper body 30A. The The main body upper portion 30A and the cartridge 31 mounted in the main body upper portion 30A constitute a paste reservoir. The cartridge 31 can be easily and inexpensively manufactured by pressing a resin film or the like.

5 (a) and 5 (b), the cartridge 31 is formed by forming a plurality of (four in this example) box portions 31a as a container portion on a horizontally long plate body 31b with a pitch in the horizontal direction by pressing or the like. It is made up of. The box portion 31a has a thin trapezoidal shape extending downward. The box portion 31a and the connecting portion 31c of the box portion 31a can be cut freely. By cutting the box portion 31c with scissors or a cutter, the number of the box portions 31a is set to an arbitrary number. It can be freely determined according to the horizontal dimension of 6. In other words, the horizontal dimension of the cartridge 31 can be adjusted to the horizontal dimension of the printing space 35 by cutting the connecting part 31c between the box part 31a and the box part 31a to change the number of the box parts 31a ( (See also FIG. 3). N is a cutting line of the connecting portion 31c, and K1 to K4 are horizontal dimensions when the number of the box portions 31a is 1 to 4, respectively. Further, the outer edge portion in the horizontal direction is sandwiched from above and below by a plate-shaped sandwiching member 39, and the sandwiching member 39 is firmly sandwiched between the main body upper part 30A, the perforated plates 32 and 33, and the main body lower part 30B (see also FIG. 3).

  As shown in FIGS. 1 to 3, a pressure plate 29 that pressurizes the cream solder P is disposed on the upper surface side of the cartridge 31 mounted in the main body upper portion 30 </ b> A. The pressure plate 29 is attached to the lower end portion of the rod 16a of the cylinder 16 disposed above. When the cylinder 16 is driven and the rod 16a protrudes and retracts, the pressure plate 29 presses the cartridge 31 downward, Also, the pressing is released. By pressing the cartridge 31 with the pressure plate 29 in this way, the cartridge 31 made of a flexible film material is easily bent and deformed, and the cream solder P in the cartridge 31 is pressurized to open the porous plate 32. The fluid flows downward through the hole 32a and is pushed out. The cylinder 16 and the pressure plate 29 serve as pressure means for pressing the cream solder 9.

A porous plate 33 that contacts the lower surface of the porous plate 32 is provided on the lower body portion 30B. The perforated plate 33 is provided with a large number of apertures 33 a at positions corresponding to the apertures 32 a of the perforated plate 32. As shown in FIG. 5, the perforated plate of Patent Document 1 has a wide opening formed on the entire surface thereof. The perforated portions 32 a and 33 a of the perforated plate are formed as shown in FIG. 7. Are formed only in the vicinity of the central portion K in the lateral direction (X direction), and are not formed on both side portions. That is, both side portions of the perforated plates 32 and 33 are blind portions S in which the opening portions 32a and 33a are not formed, and the reason will be described later. As described above, the main body upper portion 30A serves as a container holding portion that houses the cartridge 31, and the main body lower portion 30B serves as a receiving portion that faces the container holding portion 30A.

  In FIG. 2, two sliding contact portions (squeegees) 36A and 36B opposite to each other in the Y (squeezing) direction are obliquely provided on the bottom portion of the lower body portion 30B with a downward slope toward the inside. The inside is a printing space 35 filled with cream solder P. The sliding contact portions 36 </ b> A and 36 </ b> B form front and rear walls of the printing space 35, and the lower end portions of the sliding contact portions 36 </ b> A and 36 </ b> B are in contact with the surface of the mask plate 12 in a state where the squeegee head 13 is lowered. The printing space 35 accommodates the pressurized cream solder P, and the cream solder P is applied to the surface of the mask plate 12 through an opening (an opening between the sliding contact portion 36A and the sliding contact portion 36B) formed on the lower surface. Contact. During the printing operation, the sliding contact portions 36A and 36B slide on the upper surface of the mask plate 12 by the movement of the squeegee head 13 in the front-rear direction, and perform squeezing that scrapes the cream solder P in the printing space 35.

  1 to 4 and 6, a shaft 40 is provided in the printing space 35 below the perforated plates 32 and 33. The shaft 40 is horizontal, and both end portions in the lateral direction are held by being coupled to the main body lower portion 30B. Two partition members 41 are mounted on the shaft 40 on the left and right sides. The partition member 41 is slid in the horizontal direction (Y direction) along the shaft 40 to adjust and set the mounting position, that is, the distance W (W1, W2) between the two, thereby defining the horizontal width of the printing space 35. (Refer to the partition member 41 shown by the arrow a and the chain line in FIG. 6). In FIG. 6, the interval W between the partition members 41 is changed to intervals W1 and W2 corresponding to the lateral dimensions L1 and L2 of the substrate 6. Further, the shaft 40 also has a rectifying action of the cream solder P pushed out from the perforated plates 32 and 33 into the printing space 35 below.

  As shown in FIG. 3, the upper surface of the partition member 41 is in contact with the lower surface of the porous plate 33, and the squeegee head 13 is lowered so that the sliding contact portions 36 </ b> A and 36 </ b> B are grounded on the mask plate 12. The lower surface of 41 is grounded to the upper surface of the mask plate 12 to form a printing space 35 surrounded by the sliding contact portions 36A and 36B and the left and right partition members 41. The partition member 41 is preferably formed of an elastic body so as to be in close contact with the lower surface of the porous plate 33 and the upper surface of the mask plate 12.

  The opening portions 32a and 33a are not opened on the entire surface of the perforated plates 32 and 33, but are intensively opened only in the central portion K as shown by the chain line in FIG. This is to prevent the paste P in the cartridge 31 from leaking downward from the side (outside) of the partition member 41 when the partition member 41 is set at a small interval W2 to cope with this. That is, the distribution width K of the opening portions 32a and 33a shown in FIG. 7 is determined by the size of the box portion 31a of the cartridge 31 and the number of box portions, and a plurality of perforated plates 32 and 33 are prepared in advance. It is configured to be exchangeable corresponding to the horizontal dimension. Of course, when the lateral dimension of the substrate is large, as in Patent Document 1, it may be replaced with a perforated plate having an opening portion on the entire surface.

Next, the screen printing operation will be described. 1 to 4 show printing when the horizontal dimension of the substrate 6 is long. In this case, a cartridge 31 having four box portions 31a shown in FIGS. 5A and 5B is used. To execute screen printing, the squeegee head 13 is lowered to bring the sliding contact portions 36A and 36B and the partition member 41 into contact with the upper surface of the mask plate 12, as shown in FIG. Then, the cartridge 31 is pressed from above by the pressure plate 29. As a result, the cream solder P flows and is pushed out from the cartridge 31 through the openings 32a and 33a into the lower printing space 35. Therefore, the squeegee head 13 is slid on the mask plate 12. As a result, the cream solder P is rolled by the sliding contact portions 36A and 36B in the printing space 35, thereby causing the rolling flow of the cream solder P, and the cream solder P sequentially into the pattern holes 12a by the sliding contact portions 36A and 36B. P is filled.

As shown in FIG. 3, the horizontal position of the partition member 41 is adjusted and set according to the size of the horizontal dimension L of the substrate 6, and the two left and right partition members 41 are located on both sides of the substrate 6. Located on the top. The upper surface of the partition member 41 is firmly in contact with the lower surface of the perforated plate 33, and the lower surface of the partition member 41 is firmly in contact with the upper surface of the mask plate 12, so that the gap G shown in FIG. Accordingly, the width of the printing space 35 in the lateral direction is defined by the partition member 41 so that the sealing property of the printing space 35 is sufficiently secured, and the cream solder P is applied to both sides of the squeegee head 13 due to the drooping of the mask plate 12. There is no leakage. As described with reference to FIG. 6, by adjusting the position of the partition member 41 according to the size of the horizontal dimension of the substrate 6, it is possible to eliminate the generation of the gap G regardless of the size of the substrate and to print space. Can be secured. When the cream solder P in the cartridge 31 is consumed by repeatedly executing the above squeezing operation, and finally the cartridge 31 is crushed by the pressure plate 21 and the cream solder P is consumed, the cartridge 31 is replaced. I do.

  What is necessary is just to set the partition member 41 in the position which can prevent that the clearance gap G generate | occur | produces in the side of the printing space 35 in short. Therefore, as shown in FIG. 3, the partition member 41 does not have to be directly above both sides of the substrate 6, and may be a position that can prevent the generation of the gap G even if the position is slightly shifted in the lateral direction. .

  FIG. 8 is a front sectional view of another usage mode of the squeegee head in one embodiment of the present invention, and FIG. 9 is an internal plan view of another usage mode of the squeegee head in one embodiment of the present invention. Shows a case where screen printing is performed on a substrate 6 having a small lateral dimension L. In this case, the cartridge 31 is cut along the cutting line N shown in FIGS. 5A and 5B, and the number of box portions 31a is reduced to one. Further, the partition members 41 are made closer to each other toward the center, so that the distance between the partition members 41 is made smaller according to the length L of the substrate 6. Of course, the number of box portions 31a can be set to an arbitrary number such as two or three according to the horizontal dimension of the substrate 6.

  In the present embodiment, the partition member 41 is slidably mounted on the shaft 40 so as to adjust its position. However, in FIG. 6, the left and right partition members 41 are fixed to the shaft 40 so that the left and right partition members are fixed. The position of the partition member may be changed and set by preparing a plurality of types of shafts 40 having different intervals W between the members 41 and exchanging the shafts 40 according to the dimensions of the substrate 6. In this case, only the shaft 40 to which the partition member 41 is fixed may be attached to and detached from the main body lower portion 30B, or the main body lower portion 30B to which the shaft 40 is attached may be replaced.

  According to the present invention, the connecting portion of the paste container is cut in accordance with the size of the horizontal dimension of the substrate to reduce the number of container portions, and the horizontal position of the partition member is adjusted and set. The width of the printing space in the horizontal direction is defined by this, thereby eliminating the leakage of paste to the side of the squeegee head due to the gap caused by the downward sag of the mask plate, and stable screen printing can be performed. In particular, it is useful as a screen printing apparatus for printing cream solder on a substrate.

The front view of the screen printing apparatus in one embodiment of this invention The side view of the screen printing apparatus in one embodiment of this invention 1 is a front sectional view of a squeegee head of a screen printing apparatus according to an embodiment of the present invention. The internal top view of the squeegee head of the screen printing apparatus in one embodiment of this invention (A) Perspective view of paste container in one embodiment of the present invention (b) Upside down perspective view of paste container in one embodiment of the present invention Explanatory drawing of the partition member of the squeegee head of the screen printing apparatus in one embodiment of this invention The top view of the perforated plate of the screen printing apparatus in one embodiment of this invention Front sectional view of other usage mode of squeegee head in one embodiment of the present invention The internal top view of the other usage condition of the squeegee head in one embodiment of this invention Sectional drawing of the other usage condition of the squeegee head of the conventional screen printing apparatus.

Explanation of symbols

6 Substrate 12 Mask plate 12a Pattern hole 13 Squeegee head 16 Cylinder 20 Head lifting part (lifting means)
29 Pressure plate 30A Upper part of main body 30B Lower part of main body 31 Cartridge 31a Box part (container part)
31b Plate body 31c Connecting portion 32, 33 Perforated plate (paste passage member)
35 Printing space 36A, 36B Sliding part 40 Shaft 41 Partition member P Cream solder (paste)
N cutting line

Claims (4)

And a squeegee head, a screen printing apparatus of a paste comprising a horizontal moving means for moving in a horizontal direction, an elevating means for elevating the squeegee head with respect to the mask plate the squeegee head with respect to the mask plate, said ski The dihead includes a paste container for containing a paste, a container holding unit for detachably holding the paste container, a pressurizing unit that pressurizes the paste in the paste container from above, and a pressure applied by the pressurizing unit. A printing space for storing the paste flowing downward and contacting the surface of the mask plate through an opening formed in the lower surface; a paste passage member interposed between the paste container and the printing space ; A partition that is arranged at a lower portion of the paste passage member according to the size of the horizontal dimension and sets a horizontal position of the printing space. Member and the squeezing direction of the front and rear wall of the print space is formed and a sliding upper surface two before and after facing sliding contact with the said mask plate, the paste container a flexible membrane-like material Formed by forming a plurality of container parts with a pitch in the lateral direction, and cutting the connecting part between the container part and the projecting part to change the number of container parts, While adjusting the horizontal dimension of the paste container to the horizontal dimension of the printing space,
The screen printing apparatus , wherein the partition member is located directly above both sides of the substrate .   The screen printing apparatus according to claim 1, wherein the container portion is a trapezoidal box portion having a divergent shape extending downward. 3. The paste screen printing apparatus according to claim 1, wherein a horizontal shaft is provided below the paste passage member, and the partition member is slidably provided on the shaft in a lateral direction. 4. The paste screen printing apparatus according to claim 3 , wherein a receiving portion facing the container holding portion is provided below the container holding portion, and both end portions of the shaft are held by the receiving portion.

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