JP4128103B2 - Screen printing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the screen printing method for printing a viscous material such as a solder paste, a conductive paste, or an adhesive on a printed wiring board, the present invention supports printing on both sides of the printed wiring board (workpiece) in the carrying direction on the carrying surface. The present invention relates to a screen printing method for carrying in a position and printing.
[0002]
[Prior art]
With the downsizing of electronic equipment, the electric circuit used for the electronic equipment is constructed by surface mounting electrical components on a printed wiring board.
[0003]
In the mounting process, a solder paste is printed at a component mounting position on the printed wiring board, then an electrical component is placed at the mounting position, and hot air is blown over the entire printed wiring board to melt and solder the solder paste. A hot air reflow method is common.
[0004]
15A to 15C and FIG. 16 show a conventional screen printing method.
The work here is the printed wiring board 2 on which the electronic component 1 has been mounted on one side, and when the solder paste is screen-printed on the upper surface of the printed wiring board 2, the printed wiring board is transported to the printing position. When the direction is the X direction, as shown in FIG. 15A, both sides in the conveyance direction are supported by the conveyance surfaces 3a and 3b of the pair of belt conveyors and are carried into the printing position.
[0005]
At the printing position A, a suction block 4 having a suction function is on standby as shown in FIG. 15B, and this suction block 4 is moved upward as shown in FIG. The upper surface of the printed circuit board 2 corrected and held by the suction block 4 is brought into contact with the plate surface portion of the screen 6 whose periphery is supported by 5. A recess 50 is formed on the upper surface of the suction block 4 in accordance with the component arrangement of the printed wiring board 2 mounted on one side.
[0006]
In this state, the solder paste 8 is printed on the printed wiring board 2 by rubbing the screen 6 with the squeegee device 7.
FIG. 17 shows the printed wiring board 2, and the long holes 9 formed along the inner side of the outline are contour parts (generally called “mimi parts”) of the inner product part after completion of mounting of the electronic component. It is formed in order to form a plurality of thin connecting portions 12 that connect the product portion 10 to the contour portion 11 so that the product portion 10 is easily broken and separated.
[0007]
In FIG. 17, areas 13a and 13b are portions supported by the conveying surfaces 3a and 3b shown in FIG. 15, and the maximum width of the suction block 4 is W1.
Thus, the printed wiring board 2 when receiving printing is attracted to the suction block 4 and locked, and is corrected and maintained to maintain its flatness.
[0008]
In addition, the point which supports the outline part of a printed wiring board is described in the following (nonpatent literature 1) etc.
[0009]
[Non-Patent Document 1]
"Handling Process Handbook 1998" Published by Japan Robot Industry Association
(Refer to the section of substrate support mechanism on pages 60-62)
[0010]
[Problems to be solved by the invention]
The point where the suction block 4 sucks the printed wiring board 2 is limited to the other spaces 14a, 14b, and 14c, avoiding the electrical component 1 mounted on the lower surface, but recently, high-density mounting has further progressed. At present, the number of points that can be adsorbed left on the product portion 10 is remarkably reduced.
[0011]
For this reason, in the case of a printed wiring board on which components are mounted on one side, warpage often occurs as indicated by a virtual line in FIG. If the number of the suction points left in the product portion 10 is small, the correction holding effect by the suction block 4 cannot be expected.
[0012]
Even when the correction holding effect by the suction block 4 is obtained, when the suction block 4 is lowered after printing to separate the printed wiring board 2 from the screen 6 (at the time of separating the plate), the screen 6 and the upper surface of the printed circuit board 1 are large and the separation of the plate is bad, the screen 6 is gradually pulled away from the printed circuit board 2 while being pulled downward as shown in FIG. At the timing when the last portion is separated from the printed wiring board 2, the screen 6 vibrates up and down, and bleeding and omission defects occur in the printing result.
[0013]
An object of the present invention is to provide a screen printing method capable of correcting and holding a printed wiring board with a suction block more reliably than in the past even in the case of high-density mounting.
[0014]
It is another object of the present invention to provide a screen printing method capable of realizing a good printing result by significantly reducing the vertical vibration of the screen at the time of releasing the plate.
[0015]
[Means for Solving the Problems]
The screen printing method according to the present invention performs the step of allowing the above-mentioned mimetic portion, which has conventionally been located on the conveyor surface of the belt conveyor that conveys the printed wiring board, to be used as an adsorption point of the adsorption block. The improvement in performance of the straightening retention effect by the block is realized.
[0016]
Further, by providing suction units before and after the support table for sucking the screen and the printed wiring board at the printing position, improvement in the vertical vibration of the screen when the plate is separated is achieved.
[0017]
In the screen printing method according to claim 1 of the present invention, when a work is supported by a transport unit and carried into a printing position, and a viscous material is screen-printed on the upper surface of the work, A suction block formed with a plurality of levers that lifts the workpiece that has arrived at the printing position from the conveyance surface of the conveyance unit, retreats the conveyance unit to a retracted position that does not contact the workpiece, and allows the plurality of levers to escape. Is lifted toward the workpiece, the workpiece is lifted from the plurality of levers by the suction block, and the workpiece is clamped between the warp correction plate and the suction block to correct the warpage of the workpiece, The lower surface of the workpiece in a state where the warp is corrected includes the portion supported by the transport unit, and is held by correction by suction with the suction block, and the state where the suction block is sucked and corrected and held. After the workpiece is separated from the warp correction plate, the viscous material is screen-printed on the workpiece in the corrected and held state.
[0018]
The screen printing method according to claim 2 of the present invention is the screen printing method according to claim 1, wherein when a viscous material is screen-printed on the work straightened and held by the suction block, the screen surface portion of the screen is straightened and held by the suction block. The upper surface of the workpiece that has been placed in contact with the workpiece is further disposed adjacent to the suction block on the workpiece side. Adsorb the screen with an adsorption device Then, the printing plate portion of the screen is brought into close contact with the upper surface of the workpiece, and after the screen printing, the workpiece is separated from the printing plate portion of the screen.
[0019]
The screen printing method according to a third aspect of the present invention is the screen printing method according to the second aspect, wherein when the work is separated from the plate surface portion of the screen after the viscous material is screen printed, the suction is performed in a state where the screen is sucked by the suction device. The workpiece is moved in a direction away from the plate surface portion of the screen with respect to the apparatus.
[0020]
The screen printing method according to claim 4 of the present invention is the screen printing portion of the screen according to claim 1, wherein the screen frame is supported by the screen frame when the viscous material is screen-printed on the work straightened and held by the suction block. When the work is held away from the plate surface portion of the screen after the upper surface of the work straightened and held by the suction block is brought into contact with the viscous material in the screen plate, the suction is provided on the work side. The workpiece is moved in a direction away from the plate surface portion of the screen with respect to the suction device in a state where the screen is sucked by the device.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the screen printing method of the present invention will be described based on specific embodiments.
[0026]
As shown in FIGS. 1 and 2, the screen device 20 disposed at the printing position A has a plate formed at the center of the screen 6 whose periphery is supported by the screen frame 5 in accordance with a target printing pattern. . When the printed wiring board 2 that is a work is carried in, the Z table 22 stands by at a position below the screen device 20.
[0027]
When the loading / unloading direction of the printed circuit board 2 is set to the X-axis direction, the Z table 22 is moved to a position below the screen device 20 and a posture control position B moved in the Y-axis direction perpendicular to the X-axis direction. It is comprised so that it can reciprocate over. A warp correction plate 23 is disposed at the posture control position B.
[0028]
The Z table 22 has an X-axis table that can move in the X-axis direction, a Y-axis table that can move in the Y-axis direction, and a direction that rotates in the same plane (on the Z-axis table that can move in the vertical direction (Z-axis direction)). A θ-axis table that can be moved in the θ direction) is stacked and attached in order, and a pair of left and right belt conveyors 24a and 24b and the like are arranged at the top as shown in FIG.
[0029]
The belt conveyors 24a and 24b convey the printed wiring board 2 that has been carried to the printing position, carry out the printed wiring board 2 that has been printed, and convey the next printed wiring board 2 to the printing position.
[0030]
The belt conveyor 24a is incorporated so as to be movable between a protruding position shown in FIG. 4 and a retracted position shown in FIG. 10 with respect to the first support table 25a fixed to the Z table 22. Biased to position.
[0031]
The belt conveyor 24b can be driven in the Y-axis direction by a pulse motor (not shown) with respect to the Z table 22 so that the interval between the belt conveyor 24b and the first support table 25a can be set and changed according to the width of the workpiece to be handled. 2 is incorporated into the second support table 25b. In addition, a regulation rail 27 that can be moved in and out of the second support table 25b in the direction of the first support table 25a by the cylinder device 26 is assembled.
[0032]
On the first and second support tables 25a and 25b, the printed wiring board 2 that has reached the printing position by the belt conveyors 24a and 24b is lifted from the conveyance surface and moved to the retracted position against the bias of the belt conveyor 24a. A conveying device retracting means 28 (see FIG. 3) for energizing is provided.
[0033]
The transport device retracting means 28 provided on the first support table 25a includes a first positioning unit 29a positioned on the lower side of the printed wiring board 2 that has reached the printing position, and a second positioning unit positioned on the upper side. 29b. The first positioning unit 29a has a stopper 30a that can protrude upward from the conveying surface of the belt conveyor 24a and a positioning hole 31a that is formed in the printed circuit board 2. A vertically movable reference pin 32a and a cylinder 33a that urges the belt conveyor 24a to the retracted position against the urge is assembled. The second positioning unit 29b includes a stopper 30b that can protrude upward from the conveying surfaces of the belt conveyors 24a and 24b, and a positioning hole 31b that is formed in the printed wiring board 2 so that the tip can be moved up and down. The reference pin 32b and a cylinder 33b for urging the belt conveyor 24a to the retracted position against the urging are assembled.
[0034]
As shown in FIGS. 4, 5, and 6, the transport device retracting means 28 provided on the second support table 25 b includes a plurality of levers 34 a, arranged at predetermined intervals in the transport direction (X-axis direction). 34b, 34c, 34d, etc. The plurality of levers 34a to 34d are pivotally supported in a horizontal posture shown in FIG. 4 and a standing posture whose tip is positioned upward from the conveyance surface as shown in FIG. The plurality of levers 34a to 34d are rotated in the standing state by moving the link 35 in the direction of the arrow 36. The movement of the link 35 is driven in synchronization with the elevation of the reference pins 32a and 32b.
[0035]
Further, the Z table 22 is provided with a suction table 4 that can be moved up and down between the first and second support tables 25a and 25b. The width W2 of the suction table 4 is wider than the width W1 of the conventional suction table 4.
[0036]
As shown in FIGS. 3 and 8, suction units 37a and 37b for sucking and holding the screen 6 at the same height as the first and second support tables 25a and 25b are provided before and after the suction block 4 in the transport direction. Is provided. Here, the suction block 4 and the suction units 37a and 37b are provided on the Z table 22 and moved up and down together.
[0037]
Each part configured as described above is configured to be operated as follows by a control device including a microcomputer as a main part.
As shown in FIG. 1 and FIG. 2, the Z table 22 of the screen printing apparatus waiting for the loading of the printed wiring board 2 at the lower position of the screen apparatus 20, when the arrival sensor 38 detects the arrival of the printed wiring board 2, As shown in FIG. 4, the stopper 30a of the first positioning unit 29a protrudes above the transport surface. The printed circuit board 2 placed on the belt conveyors 24a and 24b and arriving at the printing position comes into contact with the stopper 30a of the first positioning unit 29a and stops. The control device that detects this stops the second positioning unit 29b. The printed wiring board 2 is stopped at the printing position by projecting the stopper 30b above the conveying surface.
[0038]
Subsequently, the control device moves the Z table 22 to the attitude control position B as shown in FIG. 9, and first, here, as shown in FIG. 6, the positioning pins 32a of the first and second positioning units 29a and 29b. , 32b are raised and the tips are inserted into the positioning holes 31a, 31b (see FIG. 17) of the printed wiring board 2. At the same time, the link 35 is driven so as to rotate the plurality of levers 34a to 34d on the belt conveyor 24b side to the upright state, and the printed wiring board 2 is raised with the positioning pins 32a and 32b raised as shown in FIG. The levers 34b and 34c are lifted from the conveyor surfaces of the belt conveyors 24a and 24b.
[0039]
As shown in FIG. 5, the suction block 4 has an upright state corresponding to the plurality of levers 34a to 34d, in addition to the recesses 39a and 39b for escaping the first and second positioning units 29a and 29b. Concave portions 40a to 40d for escaping the plurality of levers 34a to 34d are formed.
[0040]
Next, the control device drives the cylinders 33a and 33b incorporated in the first and second positioning units 29a and 29b to urge the belt conveyor 24a to the retracted position as shown in FIG. The entire second support table 25b is moved relative to the Z table 22 in the Y-axis direction so that the levers 34a to 34d coincide with the positions of the recesses 40a to 40d.
[0041]
Further, as shown in FIG. 11, the control device raises the suction block 4 and brings the suction surface of the suction block 4 into contact with the printed wiring board 2 to bring the printed wiring board 2 into the reference pins 32a and 32b and the levers 34c and 34d. Lift from.
[0042]
At the next timing, the control device raises the Z table 22 as shown in FIG. 9 and FIG. 12, corrects the printed wiring board 2 between the warp correction plate 23 and the suction block 4 so that there is no warpage, The control device lowers the reference pins 32a and 32b and then drives the cylinder 26 attached to the second support table 25b to move the regulation rail 27 by a specified amount in the direction approaching the first support table 25a. The first support table 25a and the regulation rail 27 regulate the positional deviation of the printed wiring board 2 in the Y-axis direction.
[0043]
In this way, in a state where the printed wiring board 2 is sandwiched between the warp correction plate 23 and the suction block 4 and the warp is corrected, the suction block 4 has the transport surfaces of the belt conveyors 24 a and 24 b during the transport of the printed wiring board 2. Are also in contact with the areas 13a and 13b (see FIG. 17), which are the contact points.
[0044]
The control device opens the connection valve between the suction block 4 and the vacuum source to cause the printed wiring board 2 to be sucked to the suction block 4. In this state, the suction block 4 is in contact with a width W2 wider than the conventional width W1, and includes the contour portion (generally referred to as a mimetic portion) that has not been sucked and held in the past. Adsorbs.
[0045]
When the suction by the suction block 4 is completed in this way, the control device lowers the Z table 22 and separates the printed wiring board 2 from the warp correction plate 23.
In the control device, the positional relationship between the posture control position B and the plate position of the screen device 20 is registered in advance. Next, the control device stores the printed wiring board 2 held on the Z table 22 as described above. The positioning mark (not shown) formed on the printed wiring board 2 is moved back and forth and right and left at a lower position of the warp correction plate 23, and the warp is performed by one or a plurality of television cameras 41 shown in FIG. Observation through the window 23a (see FIG. 1) formed on the correction plate 23, and the X table, Y table, and the like as necessary so as to coincide with the position of the plate surface portion of the screen device 20 in a later process. Operate the θ table.
[0046]
The Z table 22 in which the holding posture of the printed wiring board 2 is corrected in this way returns to the solid line position in FIG. 2 from the posture control position B, and then rises in the Z direction as shown in FIG. The second support tables 25 a and 25 b and the suction units 37 a and 37 b are brought close to the screen 6.
[0047]
Next, the control device opens the connection valve between the first and second support tables 25a and 25b and the vacuum source, and the connection valve between the suction units 37a and 37b and the vacuum source, as shown in FIG. The screens 6 at the four corners are sucked by the first and second support tables 25a and 25b and the suction units 37a and 37b so that the plate surface portion is brought into close contact with the printed wiring board 2. H1 and H2 are suction holes of the first and second support tables 25a and 25b, and H3 is a suction hole of the suction units 37a and 37b.
[0048]
In the state where the screen 6 is adsorbed in this way, the surface of the screen 6 is checked by a laser displacement meter (not shown) for whether the screen 6 is stretched or loosened, and the screen 6 is stretched or slackened. If this occurs, the replacement of the screen 6 is notified. The process of checking the stretch or slack on the screen 6 by the laser displacement meter is programmed to be executed every time printing is performed or after a predetermined number of times printing is completed.
[0049]
Next, the control device operates the squeegee device 7 from the solid line position in FIG. 7 to the virtual line position to fill the plate of the screen 6 with the solder paste 8.
Even when the solder paste 8 is completely filled, the state in which the screen 6 is adsorbed by the first and second support tables 25a and 25b is continued, and the adsorbing by the adsorbing units 37a and 37b is turned off. 13 (a) and 13 (b), the Z table 22 is instructed to descend while the screen 6 is being sucked by the first and second support tables 25a and 25b, and the suction block 4 and the suction unit 37a. 37b are lowered to separate the printed wiring board 6 from the screen 6.
[0050]
After that, the valves between the suction block 4, the first and second support tables 25a and 25b, the suction units 37a and 37b, and the vacuum source are closed in the reverse order of FIGS. 12, 11, 10 and 6. After the vacuum suction is turned off and the suction block 4 is further lowered from the conveying surface of the belt conveyors 24a and 24b, the driving of the cylinders 33a and 33b of the first and second positioning units 29a and 29b is turned off and the belt The conveyor 24a is returned to the initial position, the second support table 25b is moved closer to the first support table 25a and returned to the initial position, and the reference pins 32a and 32b and the levers 34a to 34d are returned to the initial position. Then, the printed wiring board 2 on which the solder paste has been printed is remounted on the belt conveyors 24a and 24b.
[0051]
In this state, the stoppers 30a and 30b incorporated in the first and second positioning units 29a and 29b are lowered from the conveyance surface, and the belt conveyors 24a and 24b are operated to move the printed wiring board 2 from the printing position in the X direction. Carry out to.
[0052]
As described above, even if the printed wiring board 2 has a reduced number of points capable of being sucked by high-density mounting, the belt conveyor 24a is retracted as shown in FIGS. 6 to 10, and the second support table is used. By separating the 25b from the first support table 25a, the points that can be sucked by the suction block 4 including the areas 13a and 13b of the printed wiring board 2 placed on the transport surface can be enlarged. Even a printed wiring board 2 mounted with a density can obtain a vacuum suction action sufficient for straightening and holding.
[0053]
Further, when the plate is released, the Z table 22 is lowered while the screen 6 is adsorbed by the first and second support tables 25a and 25b and the adsorption units 37a and 37b. Even so, the vertical vibration of the screen 6 is greatly reduced, and bleeding and omission defects are unlikely to occur, and a good printing result can be obtained.
[0054]
Since the squeegee device 7 that has moved on the screen 6 passes over the section of the printed wiring board 2 as shown in FIG. 14A, it moves onto the first support table 25a. There will be no lifting. Specifically, as shown in FIG. 14B, in the case of a conventional device in which the first support table 25a is not provided adjacent to the section of the printed wiring board 2, the squeegee device 7 is connected to the printed wiring board. Immediately after passing through the section 2, the squeegee device 7 pushes down the printed wiring board 2 and the printed wiring board 2 is lifted up and bleeding occurs in the printing result. The first support table 25a is provided. As a result, the printed wiring board 2 is not lifted, and a good printing result is obtained.
[0055]
In the above embodiment, the suction point by the suction block 4 has been described as being expanded so as to include all of the areas 13a and 13b. However, the suction point includes part of the areas 13a and 13b as compared with the conventional configuration. Even in such a case, an effect can be expected.
[0056]
In the above embodiment, the solder paste is filled in the state where the screen 6 is adsorbed by the first and second support tables 25a and 25b and the adsorption units 37a and 37b. The support tables 25a and 25b are maintained in the suction state of the screen 6, but when the plate separation is good, the first and second support tables 25a and 25b and the suction units 37a and 37b are used in the section of the plate separation. It can also be configured to release the adsorption of the screen. In addition, when the screen frame 5 or the like is not distorted and the adhesion of the screen 6 to the printed wiring board 2 is good without performing screen suction, the first and second supports are provided only in the section of the plate separation. It can also comprise so that the screen 6 may be adsorb | sucked by table 25a, 25b.
[0057]
The screen 6 is attracted by the first and second support tables 25a and 25b at the time of separating the plate. However, it is better than the conventional case only by separating the plate while attracting only one side. Results are obtained. Specifically, when printing is performed by the squeegee device 7, the squeegee head reciprocates between the solid line position and the virtual line position shown in FIG. 7, and the printing operation is carried out. From the solid line position shown in FIG. In the case where the printing is performed only in the case of the outward movement toward the head, the screen 6 may be configured to be sucked only by the first support table 25a located on the lower side in the printing direction. It was confirmed that the separation of the plate could be realized.
[0058]
In the above embodiment, since the second support table 25b can be driven in the approaching and separating direction with respect to the first support table 25a according to the size of the printed wiring board 2 to be handled, it arrives at the printing position. The transfer device retracting means for lifting the printed wiring board 2 from the transfer surface and moving the pair of belt conveyors outward from both sides of the transfer direction of the workpiece to secure a space in which the suction block 4 with the maximum width W2 can be raised and lowered. The cylinders 33a and 33b are provided only on the side of the first support table 25a to move the belt conveyor 24a to the retracted position against the bias, and the belt conveyor 24b moves the entire second support table 25b to the first position. This can be realized by moving the support table 25a away from the support table 25a, and the configuration can be simplified.
[0059]
A recess 50 is formed on the upper surface of the suction block 4 according to the component arrangement of the printed wiring board 2 mounted on one side in the same manner as in the past. A manual operation is performed to replace the printed wiring board with the one having the concave portion 50 formed at a position corresponding to the component arrangement. Therefore, in any of the steps in which the suction block 4 sucks the printed circuit board 2, the flatness of the printed wiring board 2 can be checked with a laser displacement meter immediately after the model changeover, thereby detecting the replacement mistake of the suction block 4. . Examples of replacement mistakes include
Since the position of the component does not match the position of the recess 50, the component on the printed wiring board side rides on the outside of the recess 50 and is attracted to the suction block 4 with the printed wiring board warped upward. If.
[0060]
A case where the position of the component is coincident with the position of the recess 50 but the depth of the recess 50 is shallower than the component and the printed circuit board is warped and is sucked to the suction block 4.
[0061]
-The position of the component, the position of the recess 50 and the depth of the recess 50 are appropriate, but the thickness of the printed wiring board 2 is different.
Further, in the step of detecting the replacement error of the suction block 4 with the laser displacement meter, a laser displacement meter is disposed beside the television camera 41 and observed through the window 23a of the warp correction plate 23. As this time, a case where the X table, the Y table, and the θ table are executed prior to the operation so as to coincide with the position of the printing plate portion of the screen device 20 can be cited as an example.
[0062]
In the above embodiment, the case where the solder paste as the viscous material is printed on the printed wiring board has been described as an example. However, instead of the solder paste, the viscous material such as the conductive paste or the adhesive is used for the printed wiring. The same can be applied to printing on a substrate.
[0063]
【The invention's effect】
As described above, according to the screen printing method of the present invention, the work is supported by the transport unit and carried into the printing position, and when the viscous material is screen-printed on the upper surface of the work, the work arriving at the printing position is transported. The conveyance unit is retracted away from the portion, and the workpiece is corrected and held by adsorbing the workpiece with an adsorption block including the portion supported by the conveyance unit on the lower surface of the workpiece, and the corrected and held state Since the viscous body is screen-printed on the workpiece, even a high-density mounting substrate can be corrected and held with a larger vacuum suction force than before, and a good printing result can be expected.
[0064]
Further, when a viscous material is screen-printed on the work straightened and held by the suction block, the upper surface of the work straightened and held by the suction block is brought into contact with the plate surface portion of the screen, and By adsorbing the screen with an adsorbing device arranged adjacent to the adsorbing block on the side to bring the screen plate portion of the screen into close contact with the upper surface of the work, and separating the work from the plate surface portion of the screen after screen printing Further, the adhesion between the screen and the work is further improved, and a good printing result can be expected.
[0065]
Further, when the work is separated from the screen plate portion of the screen after the viscous material is screen-printed, the work is moved away from the screen plate portion of the screen with the screen being sucked by the suction device. By moving it, it is possible to minimize the vibration of the screen when the plate is released, and a good printing result can be expected.
[Brief description of the drawings]
FIG. 1 is a plan view of a main part of an apparatus for realizing a screen printing method of the present invention.
FIG. 2 is a front view of FIG.
FIG. 3 is a plan view of the main part of the screen printing apparatus according to the embodiment;
FIG. 4 is a process diagram around the first and second support tables of the embodiment;
FIG. 5 is a perspective view of the suction block according to the embodiment and the periphery thereof.
FIG. 6 is a process diagram of the embodiment.
FIG. 7 is a process diagram of the embodiment.
FIG. 8 is a perspective view of a main part of the embodiment.
FIG. 9 is a process diagram of the embodiment.
FIG. 10 is a process diagram of the embodiment.
FIG. 11 is a process diagram of the embodiment.
FIG. 12 is a process diagram of the embodiment.
FIG. 13 is an explanatory diagram at the time of releasing the plate according to the embodiment;
FIG. 14 is a cross-sectional view and explanatory view immediately after passing through the printed wiring board section of the embodiment;
FIG. 15 is an explanatory diagram of a conventional screen printing apparatus.
FIG. 16 is an explanatory diagram at the time of releasing a plate in a conventional screen printing apparatus.
FIG. 17 is a plan view of a printed wiring board as a workpiece.
[Explanation of symbols]
1 Electronic components
2 Printed wiring board (work)
3a, 3b Conveying surface of belt conveyor
4 Adsorption block
5 Screen frame
6 screens
7 Squeegee device
8 Solder paste (viscous material)
9 Long hole
10 product parts
11 Outline
12 Connecting part
13a, 13b area
14a, 14b, 14c space
20 screen device
22 Z table
A Print position
B Attitude control position
23 Warpage correction plate
24a, 24b belt conveyor
25a, 25b first and second support tables
26 Cylinder device
28 Transfer device retracting means
29a, 29b first and second positioning units
30a, 30b Stopper
31a, 31b Positioning hole
32a, 32b Reference pin
33a, 33b cylinder
34a, 34b, 34c, 34d Lever
35 links
37a, 37b Suction unit
38 Arrival sensor
39a, 39b, 40a-40d recess
41 TV camera

Claims (4)

When the work is supported by the transport unit and carried into the printing position, and the viscous material is screen printed on the upper surface of the work,
While lifting the workpiece that has arrived at the printing position from the conveyance surface of the conveyance unit by a plurality of levers,
The transport unit is retracted to a retracted position that does not contact the workpiece, the suction block formed with recesses for releasing the plurality of levers is lifted toward the workpiece, and the workpiece is lifted from the plurality of levers by the suction block. The workpiece is clamped between the warp correction plate and the suction block to correct the warp of the workpiece, and the suction including the portion supported by the transport unit on the lower surface of the workpiece in a state where the warp is corrected. Straighten and hold by adsorbing with a block,
A screen printing method in which the viscous material is screen-printed on the workpiece in the corrected and held state after the workpiece in the corrected and held state is separated from the warp correction plate. When a viscous material is screen-printed on the work straightened and held by the suction block,
The upper surface of the workpiece that is corrected and held by the suction block is brought into contact with the plate surface portion of the screen,
Further, the screen is adsorbed by an adsorbing device disposed adjacent to the adsorbing block on the work side, and the plate surface portion of the screen is adhered to the upper surface of the work,
The screen printing method according to claim 1, wherein after the screen printing, the work is separated from a plate portion of the screen. When the work is moved away from the plate surface portion of the screen after the viscous material is screen-printed, the work is moved in a direction away from the plate surface portion of the screen with respect to the suction device while the screen is sucked by the suction device. The screen printing method according to claim 2. When a viscous material is screen-printed on the work straightened and held by the suction block,
The upper surface of the workpiece that is straightened and held by the suction block is brought into contact with the plate surface portion of the screen whose periphery is supported by the screen frame,
When the work is moved away from the plate surface portion of the screen after the viscous material is filled in the screen plate, the work is placed on the suction device in a state where the screen is sucked by the suction device disposed on the workpiece side. 2. The screen printing method according to claim 1, wherein the screen is moved in a direction away from the plate surface portion of the screen.

Images