JP2018069467A - Screen printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screen printer which reacts to a state of a substrate.SOLUTION: In a screen printer, a mask 9 formed with a print pattern is held and cream solder is printed to a substrate 10 located below the mask 9. The screen printer includes: a squeegee device 4 which applies and spreads the cream solder to the mask 9 from above; a transport device 3 which transports the substrate 10 to an area below the mask 9; a substrate holding device 5 which holds the substrate 10 in a direction perpendicular to a transport direction; a substrate supporting device 7 which includes multiple backup pins 38 having different tip heights and supports the substrate 10 from below; and a lifting device 8 which moves up or down the substrate supporting device 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a screen printer corresponding to the state of a substrate.

  In a screen printing machine, a mask having a printing pattern (printing through-hole) is held, and screen printing using cream solder is performed on a substrate disposed under the mask. The screen printing machine includes a substrate transfer device for transferring a substrate, a substrate holding device for holding the transferred substrate and positioning it at a printing location, a mask holding device for positioning and holding a mask, and a screen A squeegee device for spreading cream solder on the mask from above is provided. Then, the paste-like cream solder is pushed into the print pattern while rolling on the mask with a squeegee, and application (printing) is performed on the underlying substrate.

  At that time, the substrate is positioned at a printing position directly under the mask. That is, after the substrate is transported into the apparatus by the transport device, it is lifted by the substrate support device and further clamped by the substrate holding device. As disclosed in Patent Document 1 below, the substrate support device is configured such that a plurality of backup pins are erected on the table at a position avoiding electronic components mounted on the substrate, and the table is raised. It is configured to support the substrate from below.

JP-A-2006-043502 JP 2005-093766 A

  By the way, not all of the substrates supported by the backup pins are transported while maintaining a flat state, but those having an upward curved state, a downwardly curved downward state, or a twisted state, etc. is there. Such a state can be caused by reflow heat at the time of melting the solder, for example, because the substrate is sent through primary printing, component mounting, and reflow processes. Therefore, when the secondary surface of the substrate is printed, if the substrate is warped, the backup pin having a constant height is in a state where it is floated due to insufficient height. If the squeegee moves while applying printing pressure to the substrate in this state, the substrate and the mask may be deformed when passing through an unsupported floating portion, causing a shift in the printing position. is there. Furthermore, there may be a problem that the printed shape collapses due to the squeegee passing and the deformation of the substrate and the mask returning.

  Accordingly, an object of the present invention is to provide a screen printing machine corresponding to the state of a substrate in order to solve such a problem.

  The screen printing machine according to the present invention holds a mask on which a printing pattern is formed, prints cream solder on a substrate located under the mask, and applies cream solder to the mask from above. A squeegee device that extends, a transport device that transports the substrate under the mask, a substrate holding device that holds the substrate from a direction orthogonal to the transport direction, and a plurality of backup pins with different tip heights are provided to lower the substrate. A substrate support device that supports the substrate, and a lifting device that lifts and lowers the substrate support device.

  According to the present invention, since the substrate is supported from the bottom by a plurality of backup pins having different tip heights, for example, if the backup portion composed of the plurality of backup pins is a mountain shape, the substrate is warped. Also, it can be supported by a backup pin corresponding to the state of the substrate.

It is the figure which showed the internal structure simply about one Embodiment of a screen printer. It is the figure which showed a part of board | substrate support apparatus simply. It is the top view shown about arrangement of the backup pin on a backup table about the substrate support device of a 2nd embodiment. It is the cross-sectional perspective view which showed the assembly structure of the variable pin.

  Next, an embodiment of a screen printer according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram simply showing the internal configuration of the screen printing machine according to the present embodiment. The screen printing machine 1 is configured to perform a pre-process of a component mounting machine that mounts electronic components on a substrate. The screen printing machine 1 includes a substrate transport device 3 and a squeegee device 4, a clamp device 5 that holds the substrate, a substrate support device 7 that supports the substrate from below, and a lifting device 8 that moves and positions the substrate in the vertical direction. Etc. are provided. And the control apparatus which controls the whole screen printing machine is mounted, and the predetermined control with respect to the drive part of each apparatus is performed.

  In the screen printing machine 1, the substrate 10 is carried in and out by the substrate conveying device 3, and the substrate conveying device 3 is constituted by a pair of conveyor belts 11 that support both sides of the substrate 10. The substrate 10 is fed in a direction penetrating through (machine body width direction). The substrate transport device 3 and the clamp device 5 that holds the substrate 10 are assembled to the lifting device 8. Therefore, the substrate 10 carried into the screen printing machine 1 is held by the clamp device 5 and moved up to be positioned at a printing position immediately below the mask 9. The mask 9 is fitted into a rectangular frame member 18 and attached in a horizontal state.

  On the set mask 9, linear cream solder is supplied in the body width direction. The cream solder is pushed into the printing pattern while rolling on the mask 9 by the squeegee device 4 and is applied to the substrate 10 located under the mask 9. In such a squeegee device 4, a pair of squeegee heads 401 and 402 having a squeegee are mounted on the traveling platform 12 in a state where the squeegee heads 401 and 402 can be raised and lowered by a cylinder. The traveling table 12 is slidably assembled with respect to a guide rod 13 installed in the horizontal direction (the longitudinal direction of the machine body), and can move linearly in the horizontal direction. Further, a screw shaft 15 parallel to the guide rod 13 is installed in the screen printing machine 1 in a rotatable state, and is rotated by a drive motor. A ball screw mechanism is constituted by the fixing nut and the screw shaft 15 inside the carriage 12.

  Next, on the lower side of the set mask 9, a clamping device 5 and an elevating device 8 for gripping and positioning the substrate 10 are configured. First, the lifting device 8 is assembled with a lifting platform 22 so as to slide along a vertical guide rail 21, and the lifting platform 22 is connected to a lifting motor 23 via a ball screw mechanism 24. A substrate transfer device 3, a clamp device 5, and the like are mounted on the lift table 22 via a support table 25. Although not described in detail, the support base 25 is configured such that the position of the support base 25 can be adjusted in the X direction, the Y direction, and the θ direction on the XY plane.

  A pair of mask supports 26 are erected on the support base 25 in the longitudinal direction of the machine body, and the clamp device 5 is disposed therebetween. The pair of mask supports 26 positioned in the front and rear are provided with gate-shaped legs 261 in the width direction of the machine body, and a mask support plate 262 with which the mask 9 contacts is fixed on the upper surface. One mask support 26 is configured with a ball screw mechanism in which a fixing nut inside the leg body 261 and one screw shaft 27 are screwed together. Accordingly, the distance from the other mask support 26 can be adjusted by controlling the drive motor that rotates the screw shaft 27.

  In the clamp device 5, a pair of side frames 33 are erected on the front and rear sides of a support base 31, and a screw shaft 36 is screwed into an internal fixing nut on one side frame 33 to form a ball screw mechanism. The distance from the other side frame 33 can be adjusted by the rotation of the clamping motor with respect to 36. And the clamp part 35 is formed in the upper end part of the side frame 33, and the board | substrate 10 can be hold | gripped from the width direction now by adjusting mutual distance. The conveyor belt 11 is assembled to the side frame 33 below the clamp portion 35, and the substrate transfer device 3 is configured to transfer the substrate 10 between the pair of side frames 33.

  A substrate support device 7 is provided between the pair of side frames 33. The substrate support device 7 has a plurality of backup pins 38 attached to the backup table 37 so as to avoid electronic components mounted on the substrate 10. And the support stand 31 of the clamp apparatus 5 is supported via the ball screw mechanism which converts the rotational output of the raising / lowering motor 41 into a raising / lowering motion. Further, the drive motor 42 is fixed to the support base 31, and the backup table 37 is supported via a ball screw mechanism that converts the rotation output of the elevating motor 42 into elevating motion.

  By the way, the board | substrate support apparatus 7 of this embodiment is comprised by the thing in which the several backup pin 38 is not constant height like the past, but has different height. In particular, in the present embodiment, as shown in FIG. 2, the backup pin 381 at the center portion is the tallest when viewed in the horizontal direction of the drawing (moving direction of the squeegee), and the backup pins 382 and 383 located on the left and right sides thereof. As the distance from the center increases, the height decreases. FIG. 2 is a diagram showing a part of the substrate support device 7 in a simplified manner. Therefore, the backup pins 38 (381, 382, 382) changed in three stages are shown, but more backup pins are shown. The height may change in multiple stages.

  The configuration of the backup pin 38 corresponds to an upwardly warped substrate. In other words, the entire backup portion composed of the plurality of backup pins 38 is formed in a mountain shape that matches the warped substrate, so that the entire portion can be supported by the backup pins 38 so that no floating portion is generated on the substrate 10. Yes. However, by forming the backup portion in a chevron, even if the substrate conveyed to the screen printer 1 is in a flat state or a warped state, the state of the substrate 10 at the time of printing is all deformed into a chevron. Become.

  The substrate 10 at the time of printing is pushed up from below by the backup pin 38, and the end in the width direction is disposed between the pair of clamp portions 35. At this time, in order to bring the substrate 10 in a flat state or a warped state into a warped state, the end portion of the rising substrate 10 slides with respect to the clamp portion 35, and the advance of the end portion is centered by the sliding resistance. The board 10 follows the chevron of the backup pin 38. In addition, a top-type clamp rail 350 having a flange portion 351 is attached to the clamp portion 35, and the clamp rail 350 is pressed against the side surface in the width direction of the substrate 10 from the lateral direction. A flange portion 351 is applied to the end portion from above, and the jumping up of the end portion in the width direction is pressed down.

  On the other hand, the mask 9 overlaid on the substrate 10 is attached in a state where the planar state is maintained by the frame member 18. For this reason, if the substrate 10 at the time of printing is chevron, the distance between the mask 9 and the substrate 10 will vary. For example, the tallest backup pin 381 and the shortest backup pin 383 have a difference of about 1 to 2 mm. Therefore, if the difference in the distance between the mask 9 and the substrate 10 is large, the amount of deflection of the mask 9 due to the printing pressure received from the squeegee heads 401 and 402 varies depending on the location, and the print quality is affected. In this regard, a configuration is adopted in which the mask 9 at the time of printing follows the chevron of the substrate 10. That is, a plurality of suction holes 263 opened on the upper surface are formed in the mask support plate 262 with which the mask 9 contacts, and a vacuum device (not shown) is connected to the suction holes 263.

  Therefore, in the screen printing machine 1 configured as described above, first, the substrate 10 is carried in between the pair of side frames 33 by the conveyor belt 11. Then, the backup table 37 is raised by driving the lifting motor 42, and the substrate 10 is lifted from the conveyor belt 11 so as to be pushed up by the backup pin 38, and supported in a mountain shape as shown in FIG. Further, when the screw shaft 36 is rotated, one side frame 33 moves, and the substrate 10 is sandwiched between the clamp portions 35 of both side frames 33.

  Next, by driving the lifting / lowering motor 41, the entire clamping device 5 holding the substrate 10 is raised, and the clamp portion 35 and the upper surface of the substrate 10 are substantially aligned with the height of the mask support plate 262. . Thereafter, the lift 22 is raised by driving the lift motor 23, stops at the printing position where the mountain-shaped substrate 10 is in light contact with the lower surface of the mask 9, and the raised mask support plate 262 is also positioned directly below the mask 9. Will do. Therefore, when the vacuum apparatus is driven and evacuation is performed through the suction hole 263, the mask 9 is attracted to the upper surface of the mask support plate 262, and is bent so as to follow the chevron-shaped substrate 10 as shown in FIG. The state of the mask 9 is maintained.

  Then, on the upper surface side of the mask 9, the supplied cream solder is pushed into the print pattern while rolling on the mask 9 by the squeegee device 4. Thereby, the cream solder is printed on the substrate 10 located under the mask 9 through the through hole of the print pattern. At this time, the height of the squeegee heads 401 and 402 is adjusted by the cylinder while moving according to the height of the upper surface of the mask 9, and the cream solder is rolled with a constant printing pressure. The height adjustment of the squeegee heads 401 and 402 is performed while measuring a change in the upper surface height of the mask 9 using a load cell or the like. Alternatively, since the chevron shape on the surface of the mask 9 can be grasped from the difference in height of the plurality of backup pins 38, the height of the squeegee heads 401 and 402 may be adjusted based on a numerical value input in advance.

  Therefore, according to the screen printing machine 1 of the present embodiment, the backup portion composed of the plurality of backup pins 38 (381, 382, 382) is chevron-shaped, and the state of the substrate 10 at the time of printing is all deformed to the chevron. Even when the conveyed substrate 10 is warped, the entire substrate 10 is supported by the backup pins 38, so that it is possible to prevent quality degradation such as misalignment of printing.

  Subsequently, another embodiment of the substrate support device 7 of the screen printing machine will be described. In the embodiment, the state of the substrate 10 is changed according to the height of the backup pin 38, but the height of the backup pin may be changed according to the state of the substrate 10. FIG. 3 is a plan view showing the arrangement of backup pins on the backup table in the substrate support apparatus of the second embodiment. In the backup table 53, a plurality of backup pins are regularly arranged vertically and horizontally. Among the plurality of backup pins, those shown with hatching are variable pins 51 capable of changing the height up and down, and other pins are fixed pins 52 having a constant height.

  The variable pins 51 and the fixed pins 52 are approximately half of each other and are alternately arranged on the backup table 53. The fixed pin 52 is fixed upright with respect to the backup table 53, but the variable pin 51 is assembled in a state in which it can be displaced in the vertical direction with the upright posture as shown in FIG. FIG. 4 is a cross-sectional perspective view showing the assembly structure of the variable pin 51. The backup table 53 is divided into upper and lower two-layer blocks as shown in FIG. 4, and in a plan view, as shown in FIG. 3, two rows or 1 of a plurality of pins arranged in the longitudinal direction (lateral direction in the drawing). The blocks are divided into horizontal blocks 531, 532, and 533 for columns.

  In the backup table 53, a lower base block 55 and an upper cylinder block 56 are overlapped. A pin hole 551 opened upward is formed in the base block 55 in the vertical direction, and the movable pin 51 is inserted therein. The movable pin 51 has a piston 511 formed at the lower end, and a spring 57 is loaded between the bottom surface of the pin hole 551. On the other hand, the cylinder block 56 is formed with a cylinder hole 61 that is an open lateral hole, and the bottom end communicates with the air flow path 62. A locking piston 58 having an O-ring is inserted into the cylinder hole 61 so as to be able to slide while maintaining airtightness therein.

  The variable pin 51 passes through the cylinder block 56 so as to cross the cylinder hole 61. Accordingly, the cylinder block 56 is formed with a pin through hole 63 that penetrates at the position of the cylinder hole 61 vertically. The locking piston 58 inserted in the cylinder hole 61 is disposed on the air flow path 62 side behind the variable pin 51 penetrating the cylinder hole 61. That is, in the cylinder hole 61, a space closed by the locking piston 58 serves as a working chamber 611, and the locking piston 58 can move in the cylinder hole 61 by air pressure. The opposite side of the cylinder hole 61 from the working chamber 611 is opened so as to be released to the atmosphere. Therefore, a gap is provided between the horizontal blocks 531, 532, and 533.

  The air flow path 62 is formed as shown by a broken line in FIG. 3, and is connected to an air pressure adjusting device (not shown) via an air hose. Therefore, the state in the working chamber 611 can be controlled to a positive pressure or a negative pressure by the air pressure adjusting device. In the case of a positive pressure, the locking piston 58 moves to the variable pin 51 side. The locking piston 58 moves in a direction away from the variable pin 51. The locking piston 58 that is operated by positive pressure is configured such that a tip portion made of a rubber material is pressed against the variable pin 51 and the vertical movement of the variable pin 51 is restricted by the frictional resistance. . That is, the variable pin 51 that has compressed the spring 57 is temporarily maintained at a predetermined height. On the other hand, the variable pin 51 from which the locking piston 58 is separated by the negative pressure is returned to its original height by the spring 57. At this time, not the negative pressure but the inside of the working chamber 611 may be released to the atmosphere. This is because the variable pin 51 having a reduced frictional resistance with the locking piston 58 is returned to its original height by the spring 57.

  Therefore, in the screen printing machine 1 provided with such a substrate support device, when the substrate 10 is carried in as described above, the backup table 53 is lifted by the drive of the lifting motor 42 and pushed up by the backup pins 51 and 52. Then, the substrate 10 is lifted from the conveyor belt 11. At this time, when the substrate 10 is in a flat state, the spring 57 is pressed and contracted by the reaction force from the substrate 10 and the variable pin 51 is lowered. Since the height of the fixing pin 52 corresponds to the planar substrate 10, the height of the variable pin 51 is substantially aligned with the height of the fixing pin 52. In addition, even when the substrate 10 is warped, the portion bent downward is pushed up and the substrate 10 becomes flat, so that the height of the variable pin 51 is substantially equal to the height of the fixed pin 52. Become.

  On the other hand, when the substrate 10 is warped, even if the variable pin 51 is pushed down at a portion that warps upward, it stops in the middle without being lowered to the height of the fixed pin 52. Therefore, in the case of the upward warping state, the plurality of variable pins 51 are lowered by the reaction force of the substrate 10, but each stops at a different height. In this respect, even when the substrate 10 is twisted, the variable pin 51 is displaced according to the height of each part of the substrate, and the entire substrate 10 is supported by the variable pin 51 and the fixed pin 52. Become. However, some of the plurality of fixing pins 52 may not reach the board 10 depending on the location, but the variable pins 51 support the board 10 around the fixing pins 52.

  Then, after the variable pin 51 is displaced by the rise of the substrate support device in this way, the inside of the working chamber 611 becomes positive pressure by the air pressure by the working air from the air pressure adjusting device, and the lock piston 58 is moved to the side of the variable pin 51. Pressed against. Therefore, the height of the variable pin 51 pushed down by the reaction force of the substrate 10 is maintained in a state where the upper end of the variable pin 51 is brought into contact with the substrate 10 by frictional resistance with the locking piston 58. Thereafter, the entire clamp device 5 holding the substrate 10 is raised, and the clamp portion 35 and the upper surface of the substrate 10 are substantially aligned with the height of the mask support plate 262.

  Further, when the lifting platform 22 is raised, the substrate 10 is stopped at the printing position where the substrate 10 is lightly in contact with the lower surface of the mask 9, and the mask support plate 262 that is also raised is located immediately below the mask 9. Then, the vacuum device is driven to perform evacuation through the suction hole 263. On the upper surface side of the mask 9, the supplied cream solder is pushed onto the print pattern while rolling on the mask 9 by the squeegee device 4. Thereby, the cream solder is printed on the substrate 10 located under the mask 9 through the through hole of the print pattern. At this time, the squeegee heads 401 and 402 move while adjusting according to the height of the upper surface of the mask 9, and cream solder rolling is performed with a constant printing pressure.

  Therefore, according to the screen printing machine 1 of the present embodiment, since the backup pin is configured by the plurality of variable pins 51 and the fixed pins 52, the substrate 10 is warped or twisted and does not reach the substrate 10. Even if the fixing pin 52 is provided, the variable pin 51 supports the substrate 10, so that it is possible to prevent deterioration in quality such as misalignment of printing. In particular, since the variable pins 51 and the fixed pins 52 are approximately half of each other and are alternately arranged on the backup table 53, the variable pins 51 can support the fixed pins 52 with insufficient height.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
For example, the assembly structure of the variable pin 51 of the second embodiment is an improvement of the pin structure disclosed in US Pat. No. 7,942,394, but other structures may be used.
Further, in the second embodiment, a plurality of backup pins are regularly arranged vertically and horizontally for easy understanding. However, in order to avoid an electronic component, the backup pins at that location may be removed. Further, the plurality of backup pins may be irregularly arranged.

  Further, the variable pin 51 of the second embodiment is configured such that the spring 57 is pressed and contracted by the reaction force from the substrate 10 and the height of the tip follows the state of the substrate 10. In addition to this, for example, an air flow path that communicates with the lower side of the piston 511 in the pin hole 551 shown in FIG. 4 is formed, and the tip of the movable pin 51 raised by the air pressure follows the state of the substrate 10. You may do it.

DESCRIPTION OF SYMBOLS 1 ... Screen printer 3 ... Board | substrate conveyance apparatus 4 ... Squeegee apparatus 5 ... Clamp apparatus 7 ... Board | substrate support apparatus 8 ... Lifting apparatus 9 ... Mask 10 ... Board | substrate 11 ... Conveyor belt 35 ... Clamp part 38 ... Backup pin

Claims (5)

In a screen printing machine that holds a mask on which a printed pattern is formed and prints cream solder on a substrate located under the mask,
A squeegee device for spreading cream solder on the mask from above;
A transfer device for transferring a substrate under the mask;
A substrate holding device for holding the substrate from a direction perpendicular to the transport direction;
A substrate support device that supports a substrate from below with a plurality of backup pins with different tip heights, and
A screen printing machine comprising: a lifting device that lifts and lowers the substrate support device.   In the substrate support device, the heights of the tips of the plurality of backup pins are highest at the central portion of the mask when viewed in the moving direction of the squeegee, and are lowered as the distance from the central portion increases. The screen printing machine according to claim 1, wherein the screen printing machine is configured as described above.   The substrate holding device has a plurality of suction holes opened on the upper surface where the mask contacts the clamp member that holds the substrate in the width direction, and sucks and holds the mask through the suction holes. The screen printing machine according to claim 1, wherein the screen printing machine is provided.   In the substrate support apparatus, the plurality of backup pins include a variable pin having a high tip height and a fixed pin having a low tip height, and the variable pin can be positioned at a position lowered by a reaction force from the substrate. The screen printing machine according to claim 1, further comprising a variable mechanism. 5. The screen printing machine according to claim 4, wherein the substrate support device includes a plurality of the variable pins and the fixed pins arranged on a table in a substantially uniform state.

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