JP4356629B2 - 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 the electronic component mounting process, in screen printing in which paste such as cream solder or conductive paste is printed on the board, the board is in close contact with the mask plate, and the position is correct so as not to cause horizontal displacement. Need to hold. For this reason, the substrate positioning part for positioning and holding the substrate is provided with a clamping mechanism for holding the position by sandwiching the side edge of the substrate from both sides together with the substrate receiving part that contacts and supports the lower surface of the substrate. ing. Then, the plate separating operation for separating the mask plate from the substrate after the printing operation or the printing operation is performed in a state where the substrate is clamped.

  Since the clamping is performed by sandwiching the side end surface of the substrate with the clamping surface, the substrate is likely to malfunction because the substrate is out of the clamped state. It may remain on the club. In the screen printing apparatus, since the mask plate is located above the substrate receiving portion, the substrate dropped on the substrate receiving portion due to a malfunction cannot be easily visually recognized from the outside. If an abnormal substrate is overlooked and the next operation is started, various machine troubles such as biting of the substrate are caused.

For the purpose of preventing such a machine trouble, a screen printing apparatus provided with a sensor for detecting that a foreign substance such as a dropped substrate stays on the substrate receiving portion has come to be used. (For example, refer to Patent Document 1). In this patent document example, an optical sensor is disposed on the lower surface side of the conveyance rail that conveys the substrate, and the substrate that has dropped from the conveyance rail onto the substrate receiving portion shields the inspection optical axis of the optical sensor. A substrate that exists in a normal state is detected.
JP 2004-34639 A

  However, the screen printing apparatus shown in the above-mentioned patent document example has the following inconveniences in detecting a dropped abnormal substrate. That is, in the above example, in order to correctly detect the substrate in the fall state, it is necessary for the substrate to shield the inspection optical axis of the optical sensor. In the case of such a thin substrate, the inspection optical axis is not completely shielded even if the substrate is dropped, and the substrate cannot be reliably detected.

  In addition, when the substrate falls, only one side may fall and become a tilted posture, but in such a case, the substrate will deviate from the position assumed as the detection position by the optical sensor, A substrate in such a state could not be detected. As described above, in the conventional screen printing apparatus, it is difficult to reliably detect a state in which an object such as a dropped substrate is illegally present on the substrate receiving portion.

The present invention aims to dropped board to provide a screen printing apparatus which can reliably detect the conditions that exist in an abnormal on board bearing portion.

In the screen printing apparatus of the present invention, the paste is applied to the substrate through the pattern hole by bringing the mask plate provided with the pattern hole into contact with the substrate, supplying the paste onto the mask plate, and sliding the squeegee. A screen printing apparatus for printing, comprising: a substrate transport means for transporting the substrate by means of two parallel transport rails; and a substrate receiver for receiving and holding the substrate transported to the printing position from below. And an elevating means for elevating and lowering the substrate receiving portion relative to the transport rail, and in an abnormal state on the upper surface of the substrate receiving portion in the lowering operation of raising the substrate receiving portion. and detecting means for detecting a substrate, said detecting means, the height position of the conveyed rail integrally movably disposed inspection optical axis than the upper surface of the board bearing portion in a lowered position High and the optical sensor arranged shielding type as inspection optical axis is substantially parallel to the laying direction of the conveying rails, the substrate in the course of the board bearing portion is provided below the conveying rail is raised The end of the substrate that has fallen completely or half-falls on the lower receiving portion is displaced upward by contacting the detection surface, which is the lower surface of the substrate facing the upper surface of the lower substrate receiving portion, and the inspection optical axis is moved by the light shielding portion. And a detection member for shielding light.

According to the present invention, the detecting means for detecting the substrate existing in the abnormal state on the upper surface of the substrate receiving portion, the optical sensor disposed integrally with the transport rail with the inspection optical axis set at a predetermined position, by the substrate to be detected is constituted by a detection member for shielding the inspection optical axis is displaced upward by coming into contact with the detection surface, it is possible to reliably detect all falling or semi fallen board.

  Next, embodiments of the present invention will be described with reference to the drawings. 1 is a side view of a screen printing apparatus according to an embodiment of the present invention, FIG. 2 is a front 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. FIG. 4 is a perspective view of the detecting means provided in the screen, FIG. 4 is a diagram for explaining the operation of the detecting means provided in the screen printing apparatus according to the embodiment of the invention, and FIGS. 5, 6, and 7 are one embodiment of the invention. It is explanatory drawing of the example of an abnormal state detection in the screen printing apparatus of a form.

  First, the structure of the screen printing apparatus will be described with reference to FIGS. In FIG. 1, the screen printing apparatus is configured by disposing a screen printing mechanism above a substrate positioning unit 1. The substrate positioning unit 1 is configured by stacking a Y-axis table 2, an X-axis table 3, and a θ-axis table 4, and further combining a first Z-axis table 5 and a second Z-axis table 6 thereon. Yes.

  The configuration of the first Z-axis table 5 will be described. Similarly, on the upper surface side of the horizontal base plate 4 a provided on the upper surface of the θ-axis table 4, the horizontal base plate 5 a is held up and down by an elevating guide mechanism (not shown). The base plate 5a is moved up and down by a Z-axis lifting mechanism configured to rotationally drive a plurality of feed screws 5c through a belt 5d by a motor 5b.

  A vertical frame 5e is erected on the base plate 5a, and a substrate transport mechanism 8 is held at the upper end of the vertical frame 5e. The substrate transport mechanism 8 includes two transport rails 8a arranged in parallel to the substrate transport direction (X direction--the direction perpendicular to the paper surface in FIG. 1), and the substrate 10 to be printed is provided by these transport rails 8a. Support both ends and transport. By driving the first Z-axis table 5, the substrate 10 held by the transport rail 8a can be lifted and lowered together with the transport rail 8a with respect to a screen printing mechanism described later.

As shown in FIG. 2, on the upstream side (left side in FIG. 2) and downstream side of the transport rail 8a,
A substrate carry-in rail 8b and a substrate carry-out rail 8c are connected to each other. The substrate 10 carried in from the upstream side via the substrate carry-in rail 8b is transferred to the carrying rail 8a and positioned by the substrate positioning unit 1, and the substrate 10 after being printed by the screen printing mechanism described later is taken out of the substrate. It is carried out downstream by the rail 8c. The substrate transport mechanism 8 is a substrate transport means for transporting the substrate 10 by means of two transport rails arranged in parallel.

  The configuration of the second Z-axis table 6 will be described. A horizontal base plate 6a is disposed between the substrate transport mechanism 8 and the base plate 5a so as to be movable up and down along a lifting guide mechanism (not shown). The base plate 6a is moved up and down by a Z-axis lifting mechanism configured to rotationally drive a plurality of feed screws 6c through a belt 6d by a motor 6b. On the upper surface of the base plate 6a, a substrate lower receiving portion 7 having a plurality of lower receiving pins 7a (see FIG. 6) is disposed.

  By driving the second Z-axis table 6, the substrate receiving part 7 moves up and down with respect to the substrate 10 held by the transport rail 8 a. The plurality of lower receiving pins 7a abut against the lower surface of the substrate 10, whereby the substrate receiving portion 7 supports the substrate 10 from the lower surface side. That is, the substrate receiving unit 7 receives and holds the substrate 10 conveyed from below to a printing position by a screen printing mechanism described later. The second Z-axis table 6 is an elevating unit that elevates and lowers the substrate receiving part 7 relative to the transport rail 8a.

  A clamp mechanism 9 is disposed on the upper surface of the transport rail 8a. The clamp mechanism 9 includes two clamp members 9a that are disposed opposite to each other on the left and right sides. The clamp member 9a on one side is advanced and retracted by the drive mechanism 9b, thereby clamping and fixing the substrate 10 from both sides. Below the transport rail 8a, the substrate detector 11 is disposed integrally with the transport rail 8a. As shown in FIG. 2, the substrate detection unit 11 has a configuration in which an optical sensor including a light projecting unit 12a and a light receiving unit 12b and a detection member 13 (see FIG. 3) are combined. The detection member 13 is a conveyance rail 8a. Is mounted on the lower surface side of the frame 8d (see FIG. 4). The detailed structure and function of the substrate detection unit 11 will be described later.

  Next, the screen printing mechanism disposed above the substrate positioning unit 1 will be described. 1 and 2, a mask plate 15 is extended on the mask frame 14, and the mask plate 15 is provided with a pattern hole 15a corresponding to an object to be printed. A squeegee head 16 is disposed on the mask plate 15. The squeegee head 16 has a structure in which a squeegee raising / lowering mechanism 18 for raising and lowering the squeegee 19 is disposed on a horizontal plate 17. As shown in FIG. 2, both ends of the plate 17 are guides arranged on a vertical frame 21. The mechanism is supported so as to be slidable in the Y direction. The plate 17 is horizontally moved in the Y direction by squeegee moving means including a nut 20c, a feed screw 20b, and a rotary drive motor 20a. Further, by driving the squeegee lifting mechanism 18, the squeegee 19 moves up and down and comes into contact with the upper surface of the mask plate 15.

  Next, with reference to FIG. 3 and FIG. 4, the structure and function of the board | substrate detection part 11 are demonstrated. As will be described later, the substrate detection unit 11 detects the substrate 10 existing in an abnormal state on the substrate receiving unit 7, that is, the substrate 10 dropped on the substrate receiving unit 7 from the clamped state by the clamp mechanism 9 during the printing operation. It is provided for detection. As shown in FIG. 3, the substrate detection unit 11 uses a light-shielding optical sensor that detects an object based on the presence or absence of light shielding of the inspection optical axis a in which the light projected from the light projecting unit 12a reaches the light receiving unit 12b. Here, the optical sensor is arranged with the inspection optical axis a arranged in the X direction.

In this substrate detection, since the conventional apparatus employs a method of detecting the presence or absence of a substrate by shielding the inspection optical axis according to the thickness of the substrate, when the detection target is a thin substrate, the inspection optical axis is completely The light was not shielded and a detection error occurred. Further, since the position of the inspection optical axis is fixed, there has been a situation in which the substrate 10 that has fallen in an abnormal state cannot stably detect the substrate without blocking the inspection optical axis.

  In order to prevent such light shielding instability, in the present embodiment, instead of directly shielding the detection optical axis a by the thickness of the substrate itself, the substrate 10 falls from the range that is the substrate detection target range, that is, the transport rail 8a. The detection member 13 having the shape described below is arranged in the vicinity of the detection optical axis a in a range where there is a possibility of this. When the substrate 10 is present on the substrate support 7, the substrate 10 abuts on the detection member 13 and is displaced when the substrate support 7 is raised, whereby the detection member 13 blocks the inspection optical axis a. The presence / absence of the substrate 10 is detected.

  The detection member 13 is manufactured by forming a thin plate into a cross-sectional shape as shown in FIGS. 3A and 4A by bending or joining, and is manufactured in a length corresponding to the above-described substrate detection target range. ing. That is, the detection member 13 extends from the horizontal portion 13a on the lower surface side when attached to the substrate transport mechanism 8 to the inclined portion 13b inclined obliquely upward on the outside (right side in FIG. 3A), and further to the inclined portion. The mounting surface 13c extends horizontally from 13b toward the outside, and is mounted below the transport rail 8a in a posture in which the mounting surface 13c is along the lower surface of the frame 8d.

A light shielding portion 13f that forms a YZ plane for shielding the inspection optical axis a in the X direction is provided at the inner end (left side in FIG. 3A) of the horizontal portion 13a. The light shielding portion 13f has an end portion connected to an elevating surface portion 13d that is erected at a right angle to the horizontal portion 13a. I'm out. The horizontal portion 13a and the upper surface portion 13e arranged at intervals in the vertical direction are detection surfaces on which the detection target substrate 10 abuts in a substrate detection operation described later.

  Instead of the detection member 13 shown in FIG. 3A, a detection member 13A shown in FIG. 3B may be used. The detection member 13A is changed from a horizontal portion 13a that extends to a position directly below the upper surface portion 13e in the detection member 13 to a horizontal portion 13a ′ that is connected to the lower end portion of the elevation surface portion 13d by a bending line. It is a thing. In this cross-sectional shape, the detection unit A is small, but the detection range is not narrowed because the detection unit B exists immediately above, and the detection function is not impaired. Further, by adopting such a cross-sectional shape, there is an advantage that in the process of manufacturing the detection member with a thin plate, all can be easily manufactured only by bending.

  FIG. 4A shows a state in which the substrate detection unit 11 is mounted on the substrate transport mechanism 8. In this state, the light projecting unit 12a and the light receiving unit 12b are arranged such that the inspection optical axis a is positioned directly below the transport rail 8a and higher than the height of the upper surface of the substrate receiving unit 7 in the lowered state. . When the detection member 13 is attached, the position is adjusted so that the upper surface portion 13e is located immediately below the transport rail 8a, and the attachment surface 13c of the detection member 13 is fixed to the lower surface of the frame 8d.

  At this time, the relative position of the inspection optical axis a and the detection member 13 is adjusted so that the inspection optical axis a is positioned in a space between the upper surface portion 13e and the upper end portion of the light shielding portion 13f in a normal state. As for the relative position of the detection member 13 and the transport rail 8a, the front end of the upper surface portion 13e is the same inward / outward position as the front end of the transport rail 8a, or the upper surface portion 13e protrudes somewhat inward. Adjust as follows. When changing the conveyance width when changing the substrate type, the substrate detection unit 11 moves in the width direction together with the conveyance rail 8a.

As will be described later, when the substrate support 7 is raised in the screen printing operation process, the substrate 10 or other objects such as foreign matters dropped on the upper surface of the substrate support 7 from the transport rail 8a. When rising together, the end surface of the object to be detected comes into contact with the lower surface of the horizontal portion 13a or the lower surface of the upper surface portion 13e. And if the raising of the board | substrate support part 7 continues in this state, the detection member 13 will be displaced by the effect | action of the external force by contact | abutting of an object.

  That is, as shown in FIG. 4B, the detection member 13 is deformed such that the inclined surface portion 13b and the lower surface horizontal portion 13a are bent upward, and thereby the light shielding portion 13f is displaced upward, and the inspection optical axis a is changed. It leads to shading. When the light receiving unit 12b detects this light shielding state, it is detected that an object such as the substrate 10 has come into contact with the detection member 13. The lower surface side of the detection member 13 is a detection surface on which an object such as the substrate 10 abuts. Here, the lower surface A of the horizontal portion 13a is the first detection surface A, and the lower surface B of the upper surface portion 13e is the second detection surface B.

  That is, in the above configuration, the substrate detection unit 11 includes detection means for detecting an object such as the substrate 10 existing in an abnormal state on the upper surface of the substrate support 7 in the support raising operation for raising the substrate support 7. It has become. The substrate detection unit 11 is provided so as to be integrally movable below the light-shielding optical sensor including the light projecting unit 12a and the light receiving unit 12b and the conveyance rail 8a, and is displaced when the object to be detected contacts the detection surface. Thus, the detection member 13 that shields the inspection optical axis a is provided. Further, the optical sensor has a horizontal inspection optical axis a and is disposed so as to be movable integrally with the transport rail 8a. The height position of the inspection optical axis a is higher than the upper surface of the substrate receiving portion 7 in the lowered position. And the inspection optical axis a is arranged so as to be substantially parallel to the arrangement direction of the transport rail 8a.

  And the detection member 13 has a detection surface which covers the substantially full length of the board | substrate support part 7 in the space under the conveyance rail 8a, and in this Embodiment, the detection member 13 is in the space under the conveyance rail 8a. A configuration having a plurality of detection surfaces (first detection surface A, second detection surface B) arranged in the vertical direction is adopted. By providing a plurality of detection surfaces in this manner, the detection accuracy can be improved by increasing the probability that the detection target object will be detected in contact with the detection member 13 in the process of raising the substrate support 7. it can.

  A screen printing operation will be described. First, when the board | substrate 10 is carried in to the conveyance rail 8a, the 2nd Z-axis table 6 is driven, the board | substrate receiving part 7 is raised, and the lower surface of the board | substrate 10 is received. In this state, the substrate positioning unit 1 is driven to align the substrate 10 with the mask plate 15. Thereafter, the first Z-axis table 5 is driven to raise the substrate 10 together with the transport rail 8 a, contact the lower surface of the mask plate 15, and then the substrate 10 is clamped by the clamp mechanism 9. Thereby, the horizontal position of the board | substrate 10 is fixed in the squeegeeing by the squeegee unit 16. In this state, the squeegee 19 is slid on the mask plate 15 to which the cream solder as the paste is supplied, whereby the cream solder is printed on the substrate 10 through the pattern holes 15a.

  Next, an example of the substrate detection operation on the substrate receiving portion 7 in the above-described screen printing operation process will be described with reference to FIGS. FIG. 5A shows a state where the substrate 10 is released from the clamped state due to a malfunction and dropped onto the substrate receiving portion 7 while maintaining a horizontal posture when the printing plate 10 is released from the lower surface of the mask plate 15. Show. At this time, in the screen printing apparatus, the upper side of the substrate receiving portion 7 is covered with the mask plate 15, and the operator cannot visually recognize the abnormal state. For this reason, when production is continued as it is and the next operation is started, a machine trouble such as the substrate 10 rising together with the substrate receiving portion 7 bites into the transport rail 8a is caused.

Even in the case where such an abnormal state occurs, the dropped substrate 10 is detected as described below in the support raising operation in which the second Z-axis table 6 is driven to raise the base plate 6a. The That is, the base plate 6a is raised and the substrate receiving portion 7 is raised.
Then, when the substrate 10 that has been completely dropped onto the substrate receiving portion 7 rises, the lower surface of the horizontal portion 13a where the end portion 10a of the substrate 10 faces the upper surface of the substrate receiving portion 7 as shown in FIG. 4a and 5b, the lower surface A is pushed up by the end 10a, and the detection member 13 is displaced upward , as shown in FIGS. 4 (b) and 5 (b). The light shielding portion 13f of the detection member 13 is also displaced upward, and the inspection optical axis a is shielded by the light shielding portion 13f, and an abnormal state is detected.

FIG. 6 shows the horizontal position according to the relative positional relationship between the end face of the substrate 10 and the detection member 13 in the process in which the substrate 10 rises together with the substrate receiving portion 7 when the substrate 10 falls from the transport rail 8a as in FIG. The case where the lower surface of the part 13a and the board | substrate 10 did not contact | abut is shown. Even in such a case, the front end portion of the upper surface portion 13e is located at the same inner / outer position as the front end portion of the transport rail 8a, or the upper surface portion 13e is somewhat protruded inward, so that FIG. As shown in FIG. 5, when the end portion of the substrate 10 abuts on the lower surface of the upper surface portion 13e, the detection member 13 is similarly displaced upward and an abnormal state is detected.

FIG. 7A shows an example in which the substrate 10 is tilted, unlike the previous two examples, when the substrate 10 is out of the clamped state. That is, the end 10a on one side remains held on the transport rail 8a, and the end 10b on the other side is semi- dropped on the substrate receiving part 7. Even in such a case, in the process of raising the substrate receiving portion 7 by the second Z-axis table 6, as shown in FIG. 7B, the end portion 10b of the substrate 10 becomes the upper surface portion 13e. By abutting, the detection member 13 is displaced upward, and an abnormal state is similarly detected.

  As described above, by providing the substrate detection unit 11 having the above-described configuration, a thin and light-shielding optical sensor targets a substrate type for which it is difficult to obtain a stable light-shielding state, or a fallen substrate is inclined. Even when it exists in an irregular state, it is possible to reliably detect a substrate that has been dropped due to a malfunction.

  Note that the detection target of the substrate detector 11 is not limited to a dropped substrate, and when a non-regular underpin is mistakenly set in the underlayer 7 or when a foreign object such as a work tool is present Similarly, when it is left unintentionally left on the board 7, it is detected by the substrate detector 11 as an object that exists in an abnormal state.

Screen printing apparatus of the present invention has the effect that the total drop or semi fallen substrate board bearing portion on can be reliably detected, especially in particular in applications for printing the solder as a target a thin substrate Useful.

The side view of the screen printing apparatus of one embodiment of this invention 1 is a front view of a screen printing apparatus according to an embodiment of the present invention. The perspective view of the detection means provided in the screen printing apparatus of one embodiment of this invention Explanatory drawing of operation | movement of the detection means provided in the screen printing apparatus of one embodiment of this invention Explanatory drawing of the abnormal state detection example in the screen printing apparatus of one embodiment of this invention Explanatory drawing of the abnormal state detection example in the screen printing apparatus of one embodiment of this invention Explanatory drawing of the abnormal state detection example in the screen printing apparatus of one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate positioning part 5 1st Z-axis table 6 2nd Z-axis table 7 Substrate receiving part 8 Substrate conveyance mechanism 8a Conveyance rail 9 Clamp mechanism 10 Substrate 11 Substrate detection part 12a Light projection part 12b Light reception part 13 Detection member

Claims (3)

A screen printing apparatus for printing a paste on a substrate through the pattern hole by bringing a mask plate provided with a pattern hole into contact with the substrate, supplying a paste onto the mask plate, and sliding a squeegee. ,
Substrate transport means for transporting the substrate by means of two transport rails arranged in parallel, a substrate receiving portion for receiving and holding the substrate transported to the printing position from below, and this substrate receiving portion Elevating means for moving up and down relatively with respect to the transport rail, and detecting means for detecting a substrate existing in an abnormal state on the upper surface of the substrate receiving portion in the lowering operation of raising the substrate receiving portion. ,
The detection means is disposed so as to be able to move integrally with the transport rail, the height position of the inspection optical axis is higher than the upper surface of the substrate receiving portion in the lowered position, and the inspection optical axis is in the direction in which the transport rail is disposed. A light-shielding optical sensor arranged so as to be substantially parallel, and an end of the substrate that is provided below the transport rail and that has fallen completely or semi-dropped on the substrate support in the process of raising the substrate support And a detecting member that is displaced upward by contacting a detection surface that is a lower surface of the substrate receiving portion facing the upper surface of the substrate receiving portion, and that shields the inspection optical axis by the light shielding portion. Printing device. The detection member, a screen printing apparatus according to claim 1, characterized in that it comprises the detection surface that covers substantially the entire length of the board bearing portion in a space below the transport rail. The detection member, a screen printing apparatus according to claim 1, wherein a plurality of said detection surface arranged vertically at intervals in the space below the transport rail.

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