JP4244868B2 - Screen printing apparatus and screen printing method - 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 provided with a pattern hole in accordance with a printing target portion is brought into contact with the substrate, a paste is supplied onto the mask plate, and a squeegee is slid on the substrate through the pattern hole. The paste is printed.

The size of the substrate to be printed by the same screen printing apparatus is not necessarily the same, and depending on the size of the substrate, a mask plate having a different size may be exchanged for use. As such a screen printing apparatus for exchanging the mask plate, one having a function of automatically detecting the size of the set mask plate is known (see, for example, Patent Document 1).
JP 2003-175581 A

  By the way, when the mask plate is replaced in the screen printing apparatus, various mechanical parts associated with the replacement of the mask plate, such as replacement of the mechanical parts related to the size and arrangement of the mask plate according to the replaced mask plate and position adjustment, are performed. It is necessary to perform the setup change work.

  However, in the prior art examples shown in the above-mentioned patent documents, although the size detection of the mask plate is performed, the detection result is not used effectively, and the machine operator himself determines the type of the mask plate, and then the mask. It was necessary to perform a setup change operation accompanying the exchange of the plate. If this setup change operation is not properly executed, an operation failure due to interference between the mask plate and other parts, or a decrease in print quality due to a print operation not being executed under appropriate conditions is caused.

  Therefore, an object of the present invention is to provide a screen printing apparatus and a screen printing method capable of ensuring that a setup change operation accompanying a replacement of a mask plate is properly performed.

The screen printing apparatus of the present invention prints the paste on 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 that holds a plurality of types of mask plates of different sizes and has a mask holder that is configured to vary the mounting position according to the size of the mask plate, and by detecting the position of the mask holder, A mask identifying means for identifying the size of the mask plate, a work execution instructing means for executing a print preparation work corresponding to the identified mask plate based on the identification result of the mask identifying means, and a lower surface of the mask plate. A mask in which the cleaning head to be cleaned is identified by the mask identifying means. A cleaning unit that is replaceably mounted according to the size of the plate; and a display unit that displays a warning message that is set in advance with respect to items related to the type of the mask plate, and the work execution instruction unit is identified. A predetermined caution message set in advance according to the mask plate is displayed .

In the screen printing method of the present invention, a mask plate provided with a pattern hole is brought into contact with the substrate, a paste is supplied onto the mask plate, and a squeegee is slid to print the paste on the substrate through the pattern hole. And a screen printing method for cleaning the lower surface of the mask plate by a cleaning unit in which a cleaning head for cleaning the lower surface of the mask plate is replaceably mounted . A mask holding step for holding a mask holder whose mounting position is variable according to the size; a mask identification step for identifying the size of the mask plate by detecting the position of the mask holder by a mask identification sensor; and Mask plate size Look including a print preparation step of executing the printing preparatory work corresponding to the mask plate on the basis of the different result, in the printing preparation step, a preset warning message on matters related to the size of the mask plate The cleaning head is replaced in accordance with the size of the mask plate that is displayed and identified in the mask identifying step .

  According to the present invention, the step associated with the replacement of the mask plate is performed by performing the print preparation work corresponding to the mask plate based on the identification result of identifying the size of the mask plate by detecting the position of the mask holder. It is ensured that the replacement work is properly performed, and it is possible to prevent problems due to interference between the mask plate and other parts and a decrease in print quality.

  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 an explanatory diagram of the structure of the mask holder of the screen printing apparatus according to the embodiment of the present invention, and FIGS. 5 and 6 show the state of the mask plate mounted in the screen printing apparatus of the embodiment of the present invention. FIG. 7 is a block diagram showing the configuration of the control system of the screen printing apparatus according to one embodiment of the present invention, and FIG. 8 is a flowchart of work before starting printing in the screen printing method according to one embodiment of the present invention. is there.

  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 unit 10 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 placing a Z-axis table 5 thereon.

  A substrate holder 6 that holds the substrate 8 is provided on the Z-axis table 5. The board | substrate 8 is carried in on the board | substrate holding | maintenance part 6 by carrying-in conveyor 9A (refer FIG. 2), and is pinched | interposed from both sides by the clamp member 7, and a position is fixed. The printed circuit board 8 is carried out downstream by a carry-out conveyor 9B (see FIG. 2).

  A screen printing unit 10 disposed above the substrate positioning unit 1 includes a mask plate 12 extended on a mask frame 11. The mask plate 12 is provided with a pattern hole 12a (see FIG. 3) corresponding to a printing target. Here, a plurality of types of mask plates having different sizes can be used interchangeably according to the target substrate, and two types of large and small mask plates are used properly as will be described later.

  A squeegee head 13 is disposed on the mask plate 12. The squeegee head 13 has a structure in which a squeegee raising / lowering mechanism 14 for raising and lowering the squeegee 15 is disposed on a horizontal plate 13a. As shown in FIG. The mechanism is slidably supported in the Y direction. The plate 13a is horizontally moved in the Y direction by squeegee moving means including a nut 16a, a feed screw 16b, and a rotary drive motor (not shown). Further, by driving the squeegee raising / lowering mechanism 14, the squeegee 15 moves up and down and comes into contact with the upper surface of the mask plate 12.

The squeegee 15 is slid by driving the squeegee moving means on the mask plate 12 supplied with the cream solder as the paste while the Z-axis table 6 is raised and the lower surface of the mask plate 12 is in contact with the substrate 8. By moving, cream solder is printed on the substrate 8 through the pattern holes 12a. The squeegee 15 is detachably attached to the squeegee head 13 according to the size of the substrate 8, and the squeegee 15 is exchanged when the type of the substrate 8 is switched.

  A cleaning unit 20 is disposed on the side of the substrate positioning unit 1 on the Y-axis table 2. By driving the Y-axis table 2, the cleaning unit 20 moves in the Y direction together with the substrate holding unit 6, and cleans the lower surface of the mask plate 12 by the cleaning head 20 a mounted on the upper surface. The cleaning head 20a is mounted so as to be exchangeable, and is exchanged according to the size of the target mask plate 12.

  A camera 19 is provided above the screen printing unit 10. As shown in FIG. 3, the camera 19 is horizontally moved in the XY directions by the X-axis table 18 and the Y-axis table 17. The X-axis table 18 and the Y-axis table 17 serve as a camera moving mechanism that moves the camera 19. By moving the camera 19 with respect to the mask plate 12 by the camera moving mechanism, the camera 19 images an arbitrary position of the mask plate 12. A pair of recognition marks 12b is provided at the diagonal position of the mask plate 12, and the position of the mask plate 12 is recognized by detecting the position of the recognition mark 12b. The camera 19 serves as a mask imaging unit that images the mask plate 12 held by the mask holder 23 from above.

  The substrate positioning unit 1 can be moved in the Y direction from the lower side of the screen printing unit 10 by the Y-axis table 4 to move the held substrate 8 to the substrate recognition position. By moving to the substrate 8 on the substrate positioning unit 1, an arbitrary position of the substrate 8 can be imaged by the camera 19 and the substrate position can be recognized.

  The clamp member 7 is provided with an identification mark 7a for identification. By identifying the identification mark 7a with the camera 19, the type of the clamp member 7 can be determined. Therefore, the camera 19 serves as a clamp member imaging unit that images the clamp member 7 that clamps the substrate 8 from the side.

  Next, with reference to FIGS. 2, 4, and 5, a method of mounting the mask plate 12 and a size detection of the mask plate 12 will be described. As shown in FIG. 2, two bar-shaped brackets 22 are horizontally extended on the side surfaces of the vertical frame 21 provided on both sides of the substrate positioning portion 1. On the upper surface of the two brackets 22, a mask holder 23 having an L-shaped cross section composed of a horizontal bottom plate portion and a vertical standing plate portion is installed in the Y direction.

  By setting the mask frame 11 from above with the left and right mask holders 23 facing each other, the bottom plate portion of the mask holder 23 supports the mask frame 11 from below, and the standing plate portion of the mask holder 23 is The mask frame 11 is held from both the left and right sides in the X direction. The mask holder 23 is provided with a stopper 23c for positioning the mask frame 11 in the Y direction and a mask clamp portion 27.

  A portion of the mask holder 23 that comes into contact with the bracket 22 is provided with a notch 23a in which the bottom plate portion is notched by the width of the bracket 22, and the upper surface of the bracket 22 is fitted into the notch 23a. The mask holder 23 is held by the bracket 22. On the upper surface of the bracket 22, alignment marks 22b and screw holes 22a are provided at a plurality of locations corresponding to the mask size, and in a state where the standing plate portion of the mask holder 23 is aligned with the alignment marks 22b, the mask A mounting hole 23b provided in the holder 23 coincides with the screw hole 22a.

  In this state, the mask holder 23 is fixed to the bracket 22 by screwing by inserting the bolt 28 into the mounting hole 23b and screwing it into the screw hole 22a. That is, the mask holder 23 holds a plurality of types of mask plates 12 having different sizes, and the mounting position is variable according to the size of the mask plate 12.

  A holder position detection unit 24 is disposed on the inner surface of the vertical frame 21 on one side. As shown in FIG. 4, the holder position detection unit 24 includes a detection shaft 24 a, a spring 25, and a holder position detection sensor 26. The holder position detection sensor 26 is a light-shielding type optical sensor, and the end of the detection shaft 24 a is a detection end 24 b that is detected by the holder position detection sensor 26.

  The detection shaft 24a is urged inward by the spring 25, and when the tip of the detection shaft 24a is free, the detection end 24b is at a position deviated from the position detected by the holder position detection sensor 26. When the detection shaft 24 a is pushed against the urging force of the spring 25, the detection end 24 b moves to the detection position and is detected by the holder position detection sensor 26.

  When the mask plate 12 is mounted, the mask holder 23 is first fixed at an attachment position corresponding to the mask size. Then, the mask frame 11 is set on the two mask holders 23 from the upper surface, and both outer side surfaces of the mask frame 11 are set along the inner side surface of the mask holder 23. As a result, the position of the mask frame 11 in the X direction is maintained. Next, the position of the mask frame 11 in the Y direction is fixed by pressing the opposite side surface with the mask clamp portion 27 while the stopper 23c is in contact with the one side surface of the mask frame 11 in the Y direction. .

  Then, the mask frame 11 is fixed in the vertical direction by a mask pressing unit 29 disposed near both ends of the mask holder 23. The mask pressing unit 29 is configured to press a contact portion 29a provided at a position in contact with the upper surface of the mask frame 11 downward by a press actuator 29b, and drives the press actuator 29b to mask the contact portion 29a. By pressing against the upper surface of the holder 23, the vertical position of the mask frame 11 is fixed.

  In the mounting of the mask plate 12, as shown in FIG. 5, when the mask plate 12A corresponding to the small substrate is mounted, the mask holder 23 is mounted at a position corresponding to the small mask frame 11A. The detection end 24b is not in contact with the detection shaft 24a and is not detected by the holder position detection sensor 26. Thereby, it is identified that the mask plate 12A corresponding to the small substrate is mounted.

  On the other hand, as shown in FIG. 6, when the mask plate 12B corresponding to the large substrate is set, the mask holder 23 is attached at a position corresponding to the large mask frame 11B. The mask holder 23 is pushed in against the urging force of the spring 25, and the detection end 24 b moves to a detection position by the holder position detection sensor 26. Thereby, it is identified that the mask plate 12A corresponding to the large substrate is set.

  Next, the configuration of the control system of the screen printing apparatus will be described with reference to FIG. In FIG. 7, the calculation unit 35 is a CPU, and performs various calculations and processing described later by executing various programs stored in the program storage unit 36. In these calculations / processes, various data stored in the data storage unit 37 are used. The program storage unit 36 stores a printing operation program, an image processing program, a mask size identification processing program, and a work execution instruction program.

  The printing operation program is a program for a printing operation for controlling the operations of the substrate positioning unit 1 and the squeegee head 13 to print the cream solder 9 on the substrate 6. The image processing program is based on the imaging result of the camera 19, and the image processing program 30 recognizes the position of the recognition mark 12b on the mask plate 12, recognizes the position of the substrate 8, and the identification mark 7a provided on the clamp member 7 as described later. It is a program for performing the image recognition process for identification.

  The mask size identification processing program is a program for performing processing for identifying the size of the mask plate 12 mounted on the mask holder 23 based on the detection signal of the holder position detection sensor 26. Here, it is identified whether the mask plate corresponding to the large substrate or the small substrate is mounted. The work execution instruction program is a program for instructing the execution of the preparation work necessary for setting each part of the screen printing apparatus in a state matching the identified mask plate 12. In addition to the printing condition data such as the squeegee moving speed and the printing pressure value in the screen printing operation, the data storage unit 37 stores data necessary for instructing execution of the above-described preparation work.

  The operation / input unit 38 is input means such as a keyboard and a mouse, and inputs various control commands and data. The display unit 39 is a display device, and displays an automatic identification result of a mask size in a pre-print start preparatory work described later and a caution message according to the identification result, in addition to an image acquired by the camera 19. Therefore, the display unit 39 serves as a display unit that displays a preset caution message for matters related to the type of the mask plate 12.

  The image processing unit 30 performs image processing on the imaging result obtained by the camera 19. Thereby, the position recognition of the recognition mark 12b of the mask plate 12, the position recognition of the substrate 8, and the identification mark 7a provided on the clamp member 7 are performed. The mechanism control unit 31 controls mechanism units such as the substrate positioning unit 1, the cleaning unit 20, the screen printing unit 10, and the camera moving mechanism 31.

  The mask size identification unit 33 identifies the size of the mask plate 12 mounted on the mask holder 23 based on the position detection signal of the mask holder 23 by the holder position detection sensor 26. Therefore, the holder position detection sensor 26 and the mask size identification unit 33 serve as mask identification means for identifying the size of the mask plate 12 by detecting the position of the mask holder 23.

  The work execution instructing unit 34 is a function realized by the operation unit 35 executing the work execution instructing program stored in the program storage unit 36, and based on the identification result of the mask size identifying unit 33, An instruction is given to execute a print preparation operation for setting each part in a state that matches the identified mask plate 12. In other words, the work execution instructing unit 34 is a work execution instructing unit that executes a print preparation work corresponding to the identified mask plate based on the identification result of the mask identifying unit. Hereinafter, an example of the work content instructed to be executed by the work execution instruction unit 34 will be described.

  At the start of execution of the screen printing operation, the recognition mark 12b provided on the mask plate 12 for image alignment with the substrate 8 is imaged by the camera 19 to recognize the position. At this time, in order to move the camera 19 to above the recognition mark 12b, conventionally, it is necessary to manually set the movement target position of the camera 19 each time the board type is switched. Based on the identification result of the size identification unit 33, the camera movement target position stored in advance in the data storage unit 37 is commanded to the camera movement mechanism 31 via the mechanism control unit 32. That is, the work execution instructing unit 34 moves the camera 19 to an imaging position set in advance according to the identified mask plate.

  In addition, when the mask is changed along with the change of the substrate type at the start of the printing operation, a change-over operation for exchanging the clamp member 7 of the substrate positioning unit 1 with one corresponding to the substrate 8 is executed. At this time, when the setup work is not correctly executed and the incompatible clamp member 7 is attached, problems such as interference with the mask plate 12 occur in the printing operation.

  In order to prevent such a problem, in the present embodiment, the work execution instructing unit 34 causes the camera 19 to image the identification mark 7a of the clamp member 7 as a print preparation work. Then, it is determined whether or not the result of recognition processing of the imaging result by the image processing unit 30 matches the characteristic of the identification mark 7a registered in advance, thereby determining whether or not the clamp member 7 and the mask plate 12 are appropriate. In this case, a warning is displayed on the display unit 39 to that effect. Instead of providing the identification mark 7 a on the clamp member 7, the clamp member 7 may be identified by recognizing the shape of the member accompanying the clamp member 7.

  Furthermore, items related to the size of the mask plate 12 exist in each part of the screen printing apparatus. For example, the cleaning head 20a attached to the cleaning unit 20 and the squeegee 15 of the squeegee head 13 may all require replacement depending on the mask plate 12. Further, when a solder remaining amount detection sensor is provided in the screen printing unit 10, it is necessary to adjust according to the mask plate 12.

  For this reason, in the present embodiment, in relation to the replacement of the mask plate 12, a predetermined caution message that prompts the machine operator to confirm a place where there is a concern about interference with other parts or a place that affects the print quality is issued. It is displayed on the display unit 39. That is, the work execution instructing unit 34 displays a predetermined caution message set in advance according to the identified mask plate 12.

  Next, with reference to FIG. 8, a screen printing method using a screen printing apparatus having a configuration in which a plurality of types of mask plates having different sizes are selectively used according to the type of substrate will be described. FIG. 8 shows a pre-printing operation that is performed prior to a screen printing operation for printing a paste on a substrate via a mask plate.

  When the substrate type is changed in the printing operation and the mask plate 12 needs to be replaced, the mounting position of the mask holder 23 is first changed to match the mask plate 12 corresponding to the target substrate 8. (Holder position changing step) (ST1). Next, the new mask plate 12 is held by the mask holder 23 whose mounting position has been changed (mask holding step) (ST2). Then, by detecting the position of the mask holder 23 by the holder position detection sensor 26, the size of the mask plate 12 is identified by the mask size identification unit 33 (mask identification process) (ST3).

  Thereafter, based on the identification result of the size of the mask plate, a print preparation operation corresponding to the mask plate is executed (print preparation operation step) (ST4). In the print preparation work process, the work execution instructing unit 34 executes the following processing. First, a preset caution message is displayed for matters related to the size of the mask plate (ST5). The machine operator receives these warning messages and performs necessary confirmation work.

  Next, in order to recognize the position of the mask plate 12, imaging of the mask plate 12 is executed by the camera 19 (ST6). At this time, the camera 19 moves to a predetermined imaging position based on the identification result, that is, moves above the recognition mark 12b of the identified mask plate 12, and positions the recognition mark 12a at a correct position in the imaging field of view. To do.

  Next, imaging of the clamp member 7 that clamps the substrate 8 by sandwiching the substrate 8 is performed by the camera 19 (ST7), and the identification mark 7a is imaged and recognized, whereby the already-mounted clamp member 7 is identified in (ST3). It is determined whether or not it conforms to the plate 12. Then, after completing the above-mentioned printing preparation work and completing the necessary confirmation, the screen printing work is executed (ST8).

  As described above, in the screen printing apparatus configured to replace a plurality of types of mask plates having different sizes according to the type of substrate, the position of the mask holder 12 that holds the mask plate 12 is detected by detecting the position of the mask plate 12. By adopting a configuration in which the size is identified and the print preparation work corresponding to the mask plate 12 is executed based on the identification result, the machine operator himself determines the type of the mask plate and then replaces the mask plate. There is no need to perform the associated setup change work. Therefore, it is ensured that the setup change operation accompanying the replacement of the mask plate is properly performed, and it is possible to prevent problems due to interference between the mask plate and other parts and a decrease in print quality.

  The screen printing apparatus according to the present invention ensures that the setup change operation accompanying the replacement of the mask plate is properly executed, and prevents problems due to interference between the mask plate and other parts, and a decrease in print quality. This is useful in the field of printing paste such as cream solder or conductive paste on the substrate.

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 top view of the screen printing apparatus of one embodiment of this invention Structure explanatory drawing of the mask holder of the screen printing apparatus of one embodiment of this invention Explanatory drawing of the mounting state of the mask plate in the screen printing apparatus of one embodiment of this invention Explanatory drawing of the mounting state of the mask plate in the screen printing apparatus of one embodiment of this invention The block diagram which shows the structure of the control system of the screen printing apparatus of one embodiment of this invention FIG. 3 is a flowchart of the work before starting printing in the screen printing method according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate positioning part 7 Clamp member 8 Board | substrate 10 Screen printing part 11 Mask frame 12 Mask plate 13 Squeegee unit 15 Squeegee 23 Mask holder 24 Holder position detection unit 26 Holder position detection sensor

Claims (4)

A screen printing apparatus for printing a paste on a substrate through a pattern hole by bringing a mask plate provided with a pattern hole into contact with the substrate, supplying paste onto the mask plate and sliding a squeegee, A mask holder that holds a plurality of types of mask plates of different sizes and whose mounting position is variable according to the size of the mask plate, and a mask that identifies the size of the mask plate by detecting the position of the mask holder Based on the identification results of the identification means, the mask identification means, a work execution instruction means for executing a print preparation operation corresponding to the identified mask plate, and a cleaning head for cleaning the lower surface of the mask plate includes the mask identification Replace according to the mask plate size identified by the means A display unit for displaying a precaution message set in advance with respect to items related to the type of the mask plate and the cleaning unit mounted at the present, and the work execution instruction unit is preliminarily set in accordance with the identified mask plate. A screen printing apparatus, characterized by displaying a set predetermined caution message .   Clamp member imaging means for imaging a clamp member that clamps the substrate by sandwiching the substrate from the side below the mask plate, and the work execution instruction means is configured so that the already-mounted clamp member is adapted to the identified mask plate. The screen printing apparatus according to claim 1, wherein the clamp member imaging unit causes the clamp member to capture an image of the clamp member in order to determine whether the clamp member is present. The mask plate provided with the pattern holes is brought into contact with the substrate, the paste is supplied onto the mask plate and the squeegee is slid to print the paste on the substrate through the pattern holes , and the lower surface of the mask plate A screen printing method for cleaning the lower surface of the mask plate by a cleaning unit in which a cleaning head for cleaning is replaceably mounted, and the mounting positions of a plurality of types of mask plates having different sizes can be changed according to the size of the mask plate. A mask holding step for holding the mask holder configured in the above, a mask identification step for identifying the size of the mask plate by detecting the position of the mask holder by a mask identification sensor, and an identification result of the size of the mask plate. Based on the mask Look including a print preparation step of executing the printing preparatory work corresponding to over preparative, in the printing preparation process, it related to the size of the mask plate
A screen printing method for displaying a precaution message preset for the item and replacing the cleaning head in accordance with the size of the mask plate identified in the mask identifying step . In the printing preparatory work step, a clamp member that clamps the substrate by sandwiching it from the side is imaged by a clamp member imaging unit, and it is determined whether or not the already-mounted clamp member is compatible with the identified mask plate. The screen printing method according to claim 3 .

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