JP2012201024A - Screen and screen printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of application of an applying agent onto a projection and a recess even if there is such a projection and a recess on the upper surface of a substrate.SOLUTION: A printing head 4 comes down on a screen 3 supported by a screen support means and presses the screen 3 from above, and a support base 2 is lifted up to make the upper surface of a projecting surface P1 of the printed substrate P including the projection and recess on its lower surface abut against the lower surface of a flat plate 3A of the screen 3. At this time, since an interval L2 is slightly longer than an interval L1, a slight interval L3 is generated between the lower surface of a projecting plate 3B of the screen 3 and the upper surface of a recessed surface P2 of the printed substrate P. When printing is made by moving a squeegee 1, a soldering paste HP first is in contact with a paste initial contact surface 1B and inserted into each printing pattern hole of the screen 3, and printing is performed onto the print substrate P while accumulating the soldering paste HP inside the recess 1A and rolling.

Description

  The present invention relates to a screen for applying a coating agent by moving a squeegee on a substrate and a screen printer provided with the screen.

  This type of screen printing machine is disclosed in, for example, Patent Document 1. Further, as shown in FIG. 6, when the surface (printing surface side) of the printed circuit board P as a substrate supported by the support base 2 has unevenness, the convex surface P1 of the printed circuit board P is interposed via a screen. A technique of applying the solder paste HP by moving a squeegee and applying the solder paste HP onto the concave surface P2 of the printed circuit board P by a coating nozzle 50 through a discharge hole at the tip is conceivable.

JP 2000-211108 A

  However, the combined method of the imprinting method using a screen and the dispenser method using an application nozzle is not only expensive, but in the case of the latter dispenser method, since it is applied by the application nozzle for each application position, There is a problem that the production time becomes longer and the production time becomes longer when the number of application positions is large.

  Therefore, an object of the present invention is to improve the production efficiency of the coating operation of the coating agent on the concave portion and the convex portion even when the upper surface of the substrate is uneven.

  For this reason, according to the first aspect of the screen, in the screen for applying the coating agent by moving the squeegee on the substrate, the lower surface thereof is formed in an uneven shape in accordance with the uneven shape of the upper surface of the substrate. Features.

  According to a second aspect of the screen, in the screen for applying the coating agent by moving the squeegee on the substrate, the lower surface thereof is formed as a convex portion in accordance with the concave portion of the upper surface of the substrate. .

  The invention according to the third screen printing machine is characterized by including the screen according to the first or second invention.

  In the invention according to the fourth screen printing machine, when the squeegee is pressed against the screen according to the first or second invention, the position in contact with the squeegee is more forward than the moving direction during printing. A concave portion into which the coating agent enters is formed in the squeegee.

  The present invention can improve the production efficiency of the coating operation of the coating agent on the concave and convex portions even if the upper surface of the substrate has irregularities.

It is a simplified vertical side view of the principal part of the screen printing machine in the state where the squeegee is pressed against the screen. FIG. 3 is a simplified vertical side view of a main part of the screen printing machine in a state where a support base supporting a printed circuit board is lifted with a squeegee pressed against the screen. It is a simplified vertical side view of the principal part of the screen printing machine in a state where the squeegee is moved and printing on the printed circuit board is completed. It is a simplified vertical side view of the principal part of the screen printing machine in a state where printing is finished and the support base is lowered. It is a simple vertical side view of the principal part of the screen printing machine of the state which pressed the squeegee on the screen of 2nd Embodiment. It is a simplified vertical side view of the principal part of the conventional screen printer.

  Hereinafter, a screen printing machine that applies a solder paste HP, which is a coating agent, by moving a squeegee 1 onto a printed circuit board P (specifically, an electrode pad of the printed circuit board P) as a substrate will be described with reference to FIGS. The description will be given with reference.

  First, the printed circuit board P has a back surface (supported surface) supported by the support base 2 constituting the substrate support device, but the surface (printing surface side) has irregularities, and a convex surface P1 located around the surface. And a concave surface P2 located at an intermediate position. Then, a solder paste HP is printed on the convex surface P1 and the concave surface P2 of the printed circuit board P.

  The screen printing machine is disposed on a base and includes a substrate support device including a support base 2, screen support means disposed above the substrate support device, and disposed between the substrate support device and the screen support means. The first image pickup means for picking up an image of the board recognition mark attached to the printed circuit board P supported by the board support device, and the second image pickup means for picking up the screen recognition mark attached to the screen 3 supported by the screen support means. An imaging unit and a print head 4 disposed above the screen 3 are provided.

  In the substrate support apparatus, the support base 2 is moved in the XY direction (planar direction) by the X direction movement drive mechanism and the Y direction movement drive mechanism, in the rotation direction by the rotation drive mechanism, and further in the Z direction (vertical direction by the vertical movement mechanism). (Direction).

  The squeegee 1 is attached to the lower end of the print head 4 and moves in the Y-axis direction (front-rear direction of the screen printing machine) by the Y-direction moving mechanism and moves in the Z-axis direction (up-down direction) by the vertical movement mechanism. To do. When the print head 4 moves to the right in FIG. 1, the print head 4 descends and the squeegee 1 slides on the screen 3 supported by the screen support means, and a printing operation is performed.

  The upper surface of the screen 3 is a horizontal plane, and the lower surface is formed following the upper surface of the printed board P. That is, the lower surface shape of the screen 3 composed of the flat plate 3A and the convex plate 3B bonded to the lower surface of the flat plate 3A is uneven according to the upper surface shape of the printed board P. That is, the lower surface of the convex plate 3B forms a convex surface of the lower surface of the screen 3, and the lower surface of the flat plate 3A on which the convex plate 3B is not bonded forms the concave surface of the lower surface of the screen 3 as well. It is formed to be uneven according to the unevenness of the upper surface of the substrate P.

  And in the state which bonded the said convex plate 3B to the said flat plate 3A, a hole is processed and the printing pattern hole 3C1 is formed in the said flat plate 3A, and the printing pattern hole 3D is formed in the said convex plate 3B. Accordingly, the depth of the printed pattern hole in the portion where the convex plate 3B is bonded (the depth of the printed pattern hole 3C1 and the depth of 3D) is determined by the depth of the printed pattern hole 3C2 of the flat plate 3A to which the convex plate 3B is not bonded. The total depth) is constructed deeper.

  In this case, in the state where the screen 3 is supported by the screen support means and the support base 2 supporting the printed circuit board P is lowered, the flat plate 3A on which the convex plate 3B of the supported screen 3 is not bonded. The distance L1 between the lower surface of the printed circuit board P and the upper surface of the convex surface P1 of the printed circuit board P is the same as the distance L2 between the lower surface of the convex plate 3B bonded to the flat plate 3A of the screen 3 supported and the upper surface of the concave surface P2 of the printed circuit board P. Alternatively, the interval L2 is formed to be slightly longer than the interval L1.

  That is, when the support base 2 supporting the printed circuit board P is raised to perform printing, if the distances L1 and L2 as in the former are formed with the same dimensions, the lower surface of the flat plate 3A of the screen 3 and the print The upper surface of the convex surface P1 of the substrate P abuts and the lower surface of the convex plate 3B of the screen 3 and the upper surface of the concave surface P2 of the printed circuit board P abut. If the distance L2 is slightly longer than the distance L1 as in the latter case, the lower surface of the flat plate 3A of the screen 3 and the upper surface of the convex surface P1 of the printed circuit board P come into contact with each other, but the lower surface of the convex plate 3B of the screen 3 and the printed circuit board P A slight gap L3 occurs between the upper surface of the concave surface P2 (see FIG. 2).

  As in the former case, it is difficult to realistically manufacture the gaps L1 and L2 with the same dimension, and the gap L1 is mistakenly set to make the gaps L1 and L2 the same dimension. When manufactured so as to be slightly longer than L2, the coating pressure by the squeegee 1 (pressure of the solder paste HP discharged from the lower surface outlet of the print pattern hole) is larger when the depth of the print pattern hole is shallower than that of the deeper one. The flat plate 3A of the screen 3 is larger than the convex plate 3B. Especially when the total depth of the print pattern hole 3C1 and the depth of 3D is considerably long, the printing pressure is higher than that of the print pattern hole 3D. More solder paste HP from the pattern hole 3C2 leaks and spreads laterally from the opening exit of the printed pattern hole 3D, which is not preferable. Is et al.

  In the latter case, even if the distance L2 is slightly longer than the distance L1, the coating pressure by the squeegee 1 is smaller on the convex plate 3B of the screen 3 than the flat plate 3A. When the total depth is considerably long, the application amount of the solder paste HP through the print pattern holes 3D and the application amount of the solder paste HP through the print pattern holes 3C1 and 3C2 are applied units. Although there are fewer through the printed pattern holes 3C1 and 3C2 per area, the amount approaches the same amount as in the former case, and leakage does not spread from the opening exit of the printed pattern hole 3D.

  As shown in FIG. 1, when the squeegee 1 is pressed against the screen 3, the arc-shaped recess 1 </ b> A into which the solder paste HP enters in front of the moving direction at the time of printing from the position in contact with the squeegee 1. A paste initial contact surface 1B (formed in communication with the upper portion of the recess 1A) perpendicular to the attachment surface of the squeegee 1 is formed at the lower end of the squeegee 1.

  Accordingly, when printing is performed by moving the squeegee 1, the solder paste HP first contacts the paste initial contact surface 1B and is inserted into each print pattern hole of the screen 3, and further soldered into the recess 1A. It is configured to print on the printed circuit board P while accumulating and rolling the paste HP. That is, the recess 1A formed in the squeegee 1 and the initial paste contact surface 1B promote the rolling of the solder paste HP, promote the filling of the solder paste HP into each print pattern hole of the screen 3, and the printed circuit board P. Transfer printing of the solder paste HP to the substrate becomes good.

  Next, the screen printing operation will be described with reference to FIGS. First, the print head 4 is lowered onto the screen 3 supported by the screen support means by a vertical movement mechanism and presses the screen 3 from above (see FIG. 1).

  Then, the support base 2 is raised by the vertical movement mechanism of the substrate support device, and the upper surface of the convex surface P1 of the printed circuit board P is brought into contact with the lower surface of the flat plate 3A of the screen 3 (see FIG. 2). At this time, since the distance L2 is slightly longer than the distance L1, a slight distance L3 is generated between the lower surface of the convex plate 3B of the screen 3 and the upper surface of the concave surface P2 of the printed board P.

  Then, as shown in FIG. 3, the print head 4 is moved rightward, the squeegee 1 slides on the screen 3, and the printing operation is performed. When printing is performed by moving the squeegee 1, first, the solder paste HP contacts the paste initial contact surface 1B and is inserted into each print pattern hole of the screen 3, and further, the solder paste HP is placed inside the recess 1A. Is printed on the printed circuit board P while accumulating and rolling. Therefore, the recess 1A formed in the squeegee 1 and the paste initial contact surface 1B promote the rolling of the solder paste HP, and the filling of the solder paste HP into each print pattern hole of the screen 3 is promoted. Transfer printing of the solder paste HP to the substrate becomes good.

Further, since the bottom surface shape of the screen 3 is uneven according to the top surface shape of the printed board P, the printed pattern holes formed in the flat plate 3A in the region where the convex plate 3B of the screen 3 is not bonded. Solder paste HP is applied onto the convex surface P1 of the printed circuit board P through 3C2, and in the region where the convex plate 3B is bonded to the flat plate 3A of the screen 3, the printed circuit board P is disposed through the print pattern holes 3C1 and 3D. Therefore, the solder paste HP is applied onto the concave surface P2 of the printed circuit board P. Therefore, even if the upper surface which is the printing surface of the printed circuit board P is uneven, the solder paste HP is surely applied to the convex surface P1 and the concave surface P2 of the printed circuit board P. HP can be applied.

  After this application printing, the support base 2 is lowered by the vertical movement mechanism of the substrate support device (see FIG. 4), and the printed board P is lowered. Then, the squeegee is raised, and the printed circuit board P on the support base 2 is transported to a downstream device by a transport mechanism (not shown) to prepare for printing of the next printed circuit board P.

  The structure in which the bottom surface shape of the screen 3 is formed to be uneven according to the uneven top surface shape of the printed circuit board P is affixed to the flat plate 3A and the bottom surface of the flat plate 3A as in the previous embodiment. The embodiment is not limited to the case where the convex plates 3B are combined, and other embodiments as shown in FIG. 5 may be used.

  That is, it is not limited to the structure to be bonded, for example, in photoetching, it is not etched by chemically corroding the same pattern shape from both surfaces of the material plate, but by arbitrarily controlling the etching balance of each surface, any shape Or a half-etching method in which only one side of the material plate is etched halfway through the thickness, or the like. In this case, the thickness of the screen 3 is reduced to a thin portion 3E and a thick portion 3F. As a result, irregularities are formed. Various methods for manufacturing the screen 3 are conceivable, and the method is not limited.

  In this case, a shallow print pattern hole 3H1 is formed in the thin portion 3E, and a deep print pattern hole 3H2 is formed in the thick portion 3F.

  The concave and convex shape on the lower surface of the screen 3 of the present invention is formed in accordance with the concave and convex shape on the upper surface of the printed circuit board P. In any of the above embodiments, the convex surface P1 of the printed circuit board P is one and the concave surface P2 is one. The areas where the thicknesses of the screens 3 differ correspondingly to each other are the thin area and the thick area, but the convex surface P1 of the printed circuit board P, the concave surface P2 and the area where the screen 3 is thin, the thick area. However, the present invention is not limited to one, but can be applied to a plurality. That is, when there are a plurality of concave surfaces P2 or convex surfaces P1 on the printed circuit board P, the regions corresponding to the thick or thin regions of the screen 3 are positioned corresponding to the plurality of concave surfaces P2 or convex surfaces P1. It is possible to cope with this by forming a plurality.

  Further, the positions of the concave and convex areas on the upper surface of the printed circuit board P and the corresponding convex and concave areas on the lower surface of the screen 3 may be the respective peripheral edge portions and intermediate portions, and the positions thereof are not limited. .

  As in the conventional case, the combined method of the imprinting method using a screen and the dispenser method using a coating nozzle is not only expensive, but in the case of the latter dispenser method, the production time is long. However, according to the present invention, even if the upper surface of the substrate has irregularities, it is possible to improve the production efficiency of the coating operation of the coating agent on the concave and convex portions.

  Although the embodiments of the present invention have been described above, various alternatives, modifications, and variations can be made by those skilled in the art based on the above description, and the present invention is not limited to the various embodiments described above without departing from the spirit of the present invention. It encompasses alternatives, modifications or variations.

DESCRIPTION OF SYMBOLS 1 Squeegee 1A Concave part 2 Support base 3 Screen 3A Screen flat plate 3B Convex board P Printed board P1 Convex surface P2 Concave surface HP

Claims (4)

  A screen for applying a coating agent by moving a squeegee on a substrate, wherein the lower surface of the screen is formed in an uneven shape in accordance with the uneven shape of the upper surface of the substrate.   A screen for applying a coating agent by moving a squeegee on a substrate, wherein the lower surface of the screen is formed into a convex portion in accordance with the concave portion of the upper surface of the substrate.   A screen printing machine comprising the screen according to claim 1.   When the squeegee is pressed against the screen according to claim 1 or 2, a concave portion is formed in the squeegee into which the coating agent enters in front of a moving direction during printing from a position in contact with the squeegee. A screen printer characterized by that.

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