JPH0811283A - Screen printing machine - Google Patents

Abstract

PURPOSE:To provide a screen printing machine capable of shortening a printing tact and enabling highly accurate printing while preventing the generation of blur. CONSTITUTION:At the time of the separation of a screen plate 3 and a printed circuit board 1, a changeover valve 16 is changed over so as to use a plurality of speed control valves 11, 15 to control falling speed and the generation of the blur of the printing paste 5 printed on the printed circuit board 1 is prevented and, after the separation of the screen plate 3 and the printed circuit board 1, the changeover valve 16 is changed over by a lead switch 17 being the falling position detection means of a stage part 2 and a control means 18 so as to use only a speed control valve 11 to make the falling speed high to shorten a printing tact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fully automatic type screen printing apparatus for printing a printing paste such as a conductor paste or cream solder with high accuracy on an object to be printed such as a printed circuit board in a step of mounting an electronic circuit board.

[0002]

2. Description of the Related Art In recent years, a screen printing machine has been used in a cream solder printing process in a circuit mounting process of an electronic component. Correspondingly, high precision printing of cream solder has been required.

A conventional screen printing apparatus will be described below with reference to the drawings. FIG. 5 is a schematic view of a main part of a conventional screen printing device. In FIG. 5, 1 is a printed circuit board, 2 is a stage part for positioning and fixing the printed circuit board 1, 3 is a screen plate positioned above the stage part 2, 4 is a screen frame for fixing the screen plate 3,
Reference numeral 5 is a printing paste, 6 and 7 are horizontally moved while being in contact with the screen plate 3, and the printing paste 5 is printed on the printed board 1 by a left squeegee and a right squeegee. A print head unit that can be moved to the upper side, 9 is an air cylinder for moving the stage unit 2 up and down, 10
Is a speed control valve that controls the speed when the stage unit 2 moves up; 11 is a speed control valve that controls the speed when the stage unit 2 moves down; 12 is the air cylinder 9 when the stage unit 2 moves up and down. A switching valve for switching the gas to be supplied, 13 is a control means for controlling the switching valve 12, 1
4 is a muffler for exhausting gas.

The operation of the conventional screen printing machine having the above-mentioned components will be described below. After the printed circuit board 1 is positioned and fixed by the stage part 2, the switching valve 12 is switched by the control means 13, the gas that has passed through the speed control valve 11 is supplied to the air cylinder 9, and is fixed to the screen frame 4. High speed up to just under 3. At this time, the gas that has been filled in the cylinder 9 in advance is controlled at a high speed by the speed control valve 10 and is exhausted from the muffler 14. After that, the left squeegee 6 is lowered, and the print paste 8 is printed on the printed board 1 by the movement of the print head 8. Then, the switching valve 12 is switched by the control means 13, and the gas passing through the speed control valve 10 is supplied to the air cylinder 9. At this time, the speed of the gas previously filled in the cylinder 9 is controlled to a low speed by the speed control valve 11 and the gas is exhausted from the muffler 14, so that the stage portion 2 is lowered at a low speed to complete the printing.

[0005]

However, in the conventional screen printing machine shown in FIG. 5, the gas exhausted from the air cylinder 9 for raising and lowering the stage portion 2 is controlled by one speed control valve 11, so that the gas is lowered. If the speed is slowed down, only the tact of the screen printing device will be delayed in the production line of the automation of the board mounting process, which will have an effect such as waiting time for the equipment before and after the production line. It had a problem that it did not fit the form.

When the descending speed is increased to solve the above-mentioned problem of the tact, the plate separation speed between the screen plate 3 and the printed circuit board 1 is increased, so that the space between the printed circuit board 1 and the screen plate 3 is increased. There has been a problem that the printing paste 5 is evacuated for a moment and bleeding or blurring of the printing paste 5 occurs. Further, the adhesive force and the cohesive force (the force with which the particles attract each other) also differ depending on the type of the printing paste 5, and for the current general cream solder, the peeling speed of the cream solder and the cohesive force of the cream solder are measured using a tacking tester. FIG. 6 shows a relationship obtained and expressed. In the past, the mainstream of the opening of the screen plate was a large pattern, so the cohesive force of the cream solder and the opening of the screen plate do not cause bleeding or blurring even when the plate is separated at a relatively high speed (about 50 mm / sec). The solder was used so that the adhesive force on the wall surface of the part was equal. On the other hand, recently, the openings of the screen plate are small, and the pitch between the openings is becoming very narrow, so that the cream solder has been changed to be able to cope with it. And they have a plate separation speed of about 1 mm / se so that the cohesive force of the cream solder and the adhesive force of the wall surface of the opening of the screen plate become equal.
The distance from c to 20 mm / sec is common, and the plate separation speed between the printed circuit board and the screen plate is becoming more and more important, but there is a problem that conventional screen printing devices cannot handle the plate separation speed. Was there.

The present invention solves the above problems by shortening the printing tact while preventing the occurrence of bleeding and blurring,
An object of the present invention is to provide a screen printing device capable of high precision printing.

[0008]

In order to solve the above problems, a screen printing apparatus according to the present invention comprises a stage portion for positioning and fixing a printed circuit board, a screen plate located above the stage portion, and a printing plate located above the stage portion. A squeegee that prints paste, an air cylinder that raises and lowers the stage unit, a speed control valve that controls a rising speed of the stage unit when rising, and a plurality of speeds that control a descending speed of the stage unit when descending. A control valve, a switching valve that uses at least one of the speed control valves to switch the descending speed of the stage unit to two circuits of different speeds, and a switching timing that detects the ON / OFF switching timing of the switching valve. Printing is completed by switching the switching valve according to the information of the detection means and the detection means when the stage part descends. The lowering speed of the printed circuit board until it separates from the screen plate is slower than the speed at which the printed circuit board rises just below the screen plate at the start of printing, and the lowering speed is controlled faster after the printed circuit board separates from the screen plate. And a control means.

Further, in place of the air cylinder, a converter for converting an air pressure circuit into a hydraulic circuit and an air hydro cylinder are provided.

[0010]

With the above structure, when the screen plate and the printed circuit board are separated from each other, the switching valve is switched so that a plurality of speed control valves are used to control the descending speed to a low speed. It is possible to prevent bleeding or blurring of the paste, and after the plate is released, the lowering position detection means and control means of the stage section switch the switching valve to reduce the number of speed control valves used compared to when the plate is released By increasing the speed, it is possible to shorten the printing tact and to provide a screen printing device capable of high-precision printing.

[0011]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. FIG. 1 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to a first embodiment of the present invention. In addition, components having the same functions as those of the conventional screen printing apparatus in FIG. 6 are denoted by the same reference numerals, description of the same components will be omitted, and description of operation will be simplified.

As shown in FIG. 1, in addition to the conventional structure, this screen printing apparatus is provided with a speed control valve 15 for controlling the speed of the stage portion 2 when descending, and whether or not this speed control valve 15 is used. A switching valve 16 that switches between the above and the following, and a reed switch 17 that is provided between the lifting strokes of the air cylinder 9 and that detects the switching timing for turning the switching valve 16 ON / OFF are provided. Also,
In addition to the conventional control function, the control means 18 controls the switching valve 16 to be switched according to the information of the reed switch 17 when the stage part descends.

The operation of the screen printing apparatus having the above structure will be described with reference to FIG. The printed circuit board 1 is positioned and fixed by the stage unit 2, and then is raised at a high speed (speed: about 200 mm / sec) by an air cylinder 9 to just below the screen plate 3 fixed to the screen frame 4. At this time, the gas previously filled in the cylinder 9 is exhausted from the muffler 14 with its speed controlled at a high speed by the speed control valve 10. Then, the squeegee 6 is lowered and the print head 8 is moved to print the print paste 5 on the printed board 1.

Next, the switching valve 12 is controlled by the control means 18
And the gas is supplied to the air cylinder 9. The switching valve 16 is switched so that the gas previously filled in the air cylinder 9 passes through the speed control valve 11 controlled at a high speed, and further passes through the speed control valve 15 controlled at a low speed, so that the muffler is operated at a low speed. 14 is exhausted, and the stage unit 2 moves at a low speed (speed: about 10 mm / s
ec). Then, after the stage unit 2 is lowered until the printed circuit board 1 and the screen plate 3 are sufficiently separated (range: about 3 mm), when the reed switch 17 provided during the elevating stroke of the air cylinder 9 is turned on, the speed is reduced. The switching valve 16 is switched by the control means 18 so as to short-circuit the controlled speed control valve 15, the stage unit 2 is lowered at a high speed (200 mm / sec), and printing is completed.

As described above, according to the screen printing apparatus in the first embodiment of the present invention, the stage portion 2 for positioning and fixing the printed circuit board 1, the screen plate 3 located above the stage portion 2 and the printing located above the stage portion 2 are printed. A left squeegee 6 and a right squeegee 7 that print the paste 5, an air cylinder 9 that raises and lowers the stage unit 2, a speed control valve 10 that controls the rising speed of the stage unit 2 when it rises, and a speed control valve 10 that lowers the stage unit 2 when it descends. Speed control valves 11 and 15 for controlling the descending speed,
A switching valve 16 for switching the lowering speed of the stage unit 2 to two circuits of different speeds by using at least one or more speed control valves 11 and 15, and switching for detecting the ON / OFF switching timing of the switching valve 16. Reed switch 17 as timing detection means
And the reed switch 17 when the stage unit 2 descends.
And a control means 18 for switching the switching valve 16 according to the information of 1., the switching valve 16 is switched so that a plurality of speed control valves 11 and 15 are used when the screen plate 3 and the printed circuit board 1 are separated from each other. By controlling, it is possible to prevent the bleeding or blurring of the printing paste 5 printed on the printed circuit board 1, and after the plate separation, the speed is controlled by the reed switch 17 and the control means 18 which are the lowered position detection means of the stage part 2. A switching valve 16 to reduce the number of control valves 11 and 15 to be used compared to when the plate is separated.
The printing tact can be shortened by switching between the two and increasing the descending speed. As a result, it is possible to obtain a screen printing apparatus capable of performing high-precision printing and shortening the printing takt time.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to the second embodiment of the present invention. In addition, components having the same functions as those of the screen printing apparatus shown in FIGS. 1 and 6 are denoted by the same reference numerals, and the description of the same components will be omitted and the description of the operation will be simplified.

As shown in FIG. 2, in this screen printing apparatus, a proximity switch 19 mounted on the upper surface of the stage section 2 for measuring and detecting the distance from the screen plate 3 switches the switching valve 16 to ON / OFF. It is designed to detect timing. Then, the control unit 18 controls the switching valve 16 to switch according to the information of the proximity switch 19 when the stage unit 2 is lowered.

The operation of the screen printing apparatus having the above structure will be described with reference to FIG. The printed circuit board 1 is positioned and fixed by the stage unit 2, and then is raised at a high speed (speed: about 200 mm / sec) to a position right below the screen plate 3 fixed to the screen frame 4 by an air cylinder 9 as a drive source. At this time, the gas previously filled in the cylinder 9 is exhausted from the muffler 14 with its speed controlled at a high speed by the speed control valve 10. Then, the squeegee 6 is lowered and the print head 8 is moved to print the print paste 5 on the printed board 1.

Next, the switching valve 12 is controlled by the control means 18.
And the gas is supplied to the air cylinder 9. The gas filled in the air cylinder 9 in advance passes through the speed control valve 11 controlled at high speed and further passes through the speed control valve 15 controlled at low speed, and the switching valve 16 is switched so that the muffler 14 operates at low speed. Exhausted from the stage 2 at a low speed (speed: about 10 mm / se
It is lowered in c). Then, after the stage unit 2 is lowered until the printed circuit board 1 and the screen plate 3 are sufficiently separated (range: about 3 mm), when the proximity switch 19 provided on the upper surface of the stage unit 2 is turned on, it is controlled at a low speed. The switching valve 16 is switched by the control unit 18 so as to short-circuit the speed control valve 15, which has been used, and the stage unit 2 is lowered at a high speed (200 mm / sec) to complete printing.

As described above, according to the screen printing apparatus in the second embodiment of the present invention, the stage portion 2 for positioning and fixing the printed circuit board 1, the screen plate 3 located above it, and the printing plate located above it are printed. A left squeegee 6 and a right squeegee 7 that print the paste 5, an air cylinder 9 that raises and lowers the stage unit 2, a speed control valve 10 that controls the rising speed of the stage unit 2 when it rises, and a speed control valve 10 that lowers the stage unit 2 when it descends. Speed control valves 11 and 15 for controlling the descending speed,
A switching valve 16 for switching the lowering speed of the stage unit 2 to two circuits having different speeds by using at least one or more speed control valves 11 and 15, and switching for detecting ON / OFF switching timing of the switching valve 16. Proximity switch 19 as timing detection means
And the control means 1 for switching the switching valve 16 according to the information of the proximity switch 19 when the stage portion 2 is lowered.
8 is provided, and when the screen plate 3 and the printed circuit board 1 are separated from each other, the switching valve 16 is switched to use a plurality of speed control valves 11 and 15 to control the speed to a low speed, thereby printing on the printed circuit board 1. It is possible to prevent the bleeding and blurring of the printing paste 5 to be generated, and after the plate is separated, the number of speed control valves 11 and 15 to be used is changed by the proximity switch 19 and the control means 18, which are the descending position detecting means of the stage 2. The printing tact can be shortened by switching the switching valve 16 so as to reduce it compared to the time of separation and increasing the descending speed. As a result, it is possible to obtain a screen printing apparatus capable of performing high-precision printing and shortening the printing takt time.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to FIG. FIG. 3 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to the third embodiment of the present invention. In addition, components having the same functions as those of the screen printing apparatus in FIGS. 1 and 6 are denoted by the same reference numerals, description of the same components will be omitted, and the operation description will be simplified.

As shown in FIG. 3, in this screen printing apparatus, the timer 20 sets the low speed descent time of the stage section 2 to turn on / off the switching valve 16.
The switching timing is detected. Then, the control unit 18 controls the switching valve 16 to switch according to the information of the timer 20 when the stage unit 2 is lowered.

The operation of the screen printing apparatus having the above structure will be described with reference to FIG. The printed circuit board 1 is positioned and fixed by the stage unit 2, and then is raised at a high speed (speed: about 200 mm / sec) to a position right below the screen plate 3 fixed to the screen frame 4 by an air cylinder 9 as a drive source. At this time, the gas which has been filled in the cylinder 9 in advance is controlled at a high speed by the speed control valve 10 and is exhausted from the muffler 14. Then, the squeegee 6 is lowered and the print head 8 is moved to print the print paste 5 on the printed board 1.

Next, the switching valve 12 is controlled by the control means 18.
And the gas is supplied to the air cylinder 9. The switching valve 16 is switched so that the gas previously filled in the air cylinder 9 passes through the speed control valve 11 controlled at a high speed, and further passes through the speed control valve 15 controlled at a low speed, so that the muffler is operated at a low speed. 14 is exhausted, and the stage unit 2 moves at a low speed (speed: about 10 mm / s
ec). Then, after the stage unit 2 is lowered until the printed circuit board 1 and the screen plate 3 are sufficiently separated (range: about 3 mm), when the timer 20 for setting the low-speed lowering time of the stage unit 2 is turned on, the speed is controlled to be low. The switching valve 16 is switched by the control means 18 so as to short-circuit the speed control valve 15 that has been operated.
Is lowered at high speed (200 mm / sec) to complete printing.

As described above, according to the screen printing apparatus in the third embodiment of the present invention, the stage portion 2 for positioning and fixing the printed circuit board 1, the screen plate 3 located above the stage portion 2, and the printing plate located above the stage portion 3 are printed. The left squeegee 6 and the right squeegee 7 that print the paste 5, the air cylinder 9 that raises and lowers the stage unit 2, and when the stage unit 2 rises,
A speed control valve 10 for controlling the ascending speed, and a plurality of speed control valves 11 for controlling the descending speed when the stage portion 2 descends,
15, a switching valve 16 for switching the lowering speed of the stage unit 2 to two circuits of different speeds by using at least one or more speed control valves 11 and 15, and an ON / OFF switching timing of the switching valve 16. Timer 2 as detection means for detecting switching timing
0 and control means 18 for switching the switching valve 16 according to the information of the timer 20 when the stage unit 2 is lowered.
Is provided, and when the screen plate 3 and the printed circuit board 1 are separated from each other, the switching valve 16 is switched so that a plurality of speed control valves 11 and 15 are used to control at a low speed.
It is possible to prevent bleeding and blurring of the printing paste 5 printed on the printed circuit board 1, and to use the speed control valves 11 and 15 by the low speed fall time setting timer 20 of the stage unit 2 and the control means 18 after the plate is separated. The printing takt time can be shortened by switching the switching valve 16 so as to reduce the printing speed when compared with the plate separation and increasing the descending speed. As a result, it is possible to obtain a screen printing apparatus capable of performing high-precision printing and shortening the printing takt time.

(Embodiment 4) A fourth embodiment of the present invention will be described below with reference to FIG. FIG. 4 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to the fourth embodiment of the present invention. Further, constituent parts having the same functions as those of the screen printing apparatus in FIGS. 3 and 6 are designated by the same reference numerals, and the description of the same constituent parts will be omitted and the explanation of the operation will be simplified.

As shown in FIG. 4, this screen printing apparatus is provided with converters 22 and 23 for converting an air pressure circuit into a hydraulic circuit, and an air-hydro cylinder 21 correspondingly moves up and down the stage section 2. It is designed to let you. The speed control valves 10, 11, 15 and the switching valve 16 corresponding to the hydraulic circuit are used.

The operation of the screen printing apparatus having the above structure will be described with reference to FIG. The printed circuit board 1 is positioned and fixed by the stage unit 2, and is then raised at a high speed (about 200 mm / sec) to just below the screen plate 3 fixed to the screen frame 4 by an air-hydro cylinder 21 as a drive source. Then, the squeegee 6 is lowered and the print head 8 is moved to print the print paste 5 on the printed board 1.

Next, the switching valve 12 is switched by the control means, the pneumatic circuit is converted into a hydraulic circuit by the converter 23 which is a converting device, and the oil is supplied to the air-hydro cylinder 21 through the flow control valve 10. The switching valve 16 is switched so that the oil previously filled in the air-hydro cylinder 21 passes through the speed control valve 11 controlled at high speed and further passes through the speed control valve 15 controlled at low speed, and the hydraulic circuit After being converted from the air pressure circuit to the pneumatic circuit by the converter 22, it is exhausted at a low speed, and the stage portion 2 is moved at a low speed (speed: about 3 mm / sec, range: about 3 m).
m). After that, when the timer 20 that sets the time for lowering the stage unit 2 at a low speed is turned on, the switching valve 16 is switched by the control unit 18 so as to short-circuit the speed control valve 17 that was controlled at a low speed, and the stage unit 2 Is lowered at high speed (200 mm / sec),
Printing is completed.

As described above, according to the screen printing apparatus in the fourth embodiment of the present invention, the stage portion 2 for positioning and fixing the printed circuit board 1, the screen plate 3 located above the stage portion 2, and the printing plate located above the stage portion 2 are printed. The left squeegee 6 and the right squeegee 7 that print the paste 5, the converters 22 and 23 that convert air pressure into hydraulic pressure, the air-hydro cylinder 21 that moves the stage unit 2 up and down, and the rising speed when the stage unit 2 moves up are controlled. Speed control valve 10, a plurality of speed control valves 11, 15 for controlling the descending speed of the stage 2 when descending, and a descending speed of the stage 2 using at least one or more speed control valves 11, 15. Switching valve 16 for switching between two circuits each having a different speed, and detection for detecting the ON / OFF switching timing of the switching valve 16. A timer 20 which is a step and a control means 20 which switches the switching valve 16 according to the information of the timer 20 when the stage part 2 is lowered are provided, and the speed control valves 11 and 15 are used when the screen plate 3 and the printed board 1 are separated from each other. Switching valve to use multiple valves 1
By switching 6 to control at low speed, the printed circuit board 1
It is possible to prevent bleeding and blurring of the printing paste 5 printed on the surface of the printing paste, and the timer 20 and the control means 1 after the plate separation.
8, the printing tact can be shortened by switching the switching valve 16 so as to reduce the number of speed control valves 11 and 15 used compared to when the plate is separated and increasing the descending speed. As a result, it is possible to obtain a screen printing apparatus capable of performing high-precision printing and shortening the printing takt time. Particularly, since the air-hydro cylinder 21 using hydraulic pressure is used, the plate separation is performed as compared with the air cylinder using air pressure. The speed can be further slowed down, the corresponding range is wide, and printing with higher accuracy becomes possible.

In the fourth embodiment described above, the timer 20 is used as the switching timing detecting means, but instead of the timer 20, the reed switch 17 is provided as in the first embodiment. The proximity switch 19 may be provided as in the second embodiment.

[0032]

As described above, according to the screen printing apparatus of the present invention, the stage portion for positioning and fixing the printed circuit board, the screen plate positioned above the stage portion, and the squeegee for printing the printing paste positioned above the stage portion. An air cylinder for raising and lowering the squeegee portion, a speed control valve for controlling an ascending speed of the stage portion when rising, a plurality of speed control valves for controlling a descending speed of the stage portion when descending, A switching valve for switching the lowering speed of the stage part to two circuits of different speeds by using at least one speed control valve, and ON / OFF of the switching valve.
A switching timing detection means for detecting the switching timing of OFF and a control means for switching the switching valve according to the information of the detection means when the stage part descends are provided, and a plurality of speed control valves are provided when the screen plate and the printed board are separated from each other. Switch the switching valve to use the gas exhausted from the air cylinder at low speed (about 10 m
(m / sec), it is possible to prevent bleeding and blurring of the printing paste printed on the printed circuit board and to enable high-precision printing. The switching valve is switched by the detection means and the control means so as to reduce the number of speed control valves used in comparison with the plate separation time, and the descending speed is set to a high speed (about 200 m).
(m / sec) can shorten the printing tact.

Further, according to the screen printing apparatus of the present invention, the stage portion for positioning and fixing the printed circuit board, the screen plate located above the stage portion, the squeegee located above the stage for printing the printing paste, and the air pressure for hydraulic pressure. A plurality of conversion devices for converting the air conditioner, an air-hydro cylinder for elevating and lowering the stage part, a speed control valve for controlling the ascending speed of the stage part when ascending, and a descending speed of the stage part when descending. A plurality of speed control valves, a switching valve that switches at least one of the speed control valves to two circuits of different descending speeds of the stage part, and an ON / OFF switching timing of the switching valve. Detecting means for detecting and control for switching the switching valve according to the information of the detecting means when the stage part descends When the plate is separated from the screen plate and the plate, the switching valve is switched to use multiple speed control valves to control the oil discharged from the air-hydro cylinder at a low speed (about 3 mm / sec). It is possible to prevent bleeding and blurring of the printing paste printed on the printed circuit board and enable high-precision printing.After the plate separation, speed control is performed by the descending position detection means and control means of the stage section. Switch the switching valve to reduce the number of valves used compared to when the plate is separated,
The printing tact can be shortened by setting the descending speed to a high speed (about 200 mm / sec). In particular, in this case, the plate separation speed can be further reduced as compared with the air cylinder by air pressure, and the corresponding range is wide and printing with higher accuracy can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a main part of a screen printing apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a schematic view of a main part of a screen printing apparatus according to a conventional example.

FIG. 6 is a diagram showing the relationship between the cohesive force of a typical cream solder and the peeling speed.

[Explanation of symbols]

 1 Printed Circuit Board 2 Stage Section 3 Screen Plate 5 Printing Paste 6,7 Squeegee 9 Air Cylinder 10,11,15 Speed Control Valve 12,16 Changeover Valve 17 Reed Switch 18 Control Means 19 Proximity Switch 20 Timer 21 Air Hydro Cylinder 22,23 Hydro-pneumatic pressure converter

Front page continued (72) Inventor Takao Naito 1006 Kadoma, Kadoma-shi, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A stage section for positioning and fixing a printed circuit board, a screen plate located above it, a squeegee located above it for printing a printing paste, an air cylinder for raising and lowering the stage section, and the stage section. Speed control valve for controlling the ascending speed of the stage part, a plurality of speed control valves for controlling the descending speed of the stage part when descending, and the descending part of the stage part using at least one or more of the speed control valves. A switching valve that switches the speed to two circuits of different speeds, and ON / OFF of the switching valve.
Switching timing detection means for detecting the switching timing of OFF and switching valve according to the information of the detection means when the stage part descends, and the descending speed until the printed board separates from the screen plate at the end of printing is the printed board at the start of printing. The screen printing apparatus is provided with a control means for controlling the moving speed of the printed board so that it is slower than the speed of rising to just below the screen plate, and the descent speed is fast after the printed board is separated from the screen plate. 2. A stage part for positioning and fixing a printed circuit board, a screen plate located above it, a squeegee located above it for printing a printing paste, a converter for converting air pressure into hydraulic pressure, and the stage part. An air-hydro cylinder for raising and lowering, a speed control valve for controlling a rising speed of the stage part when rising, a plurality of speed control valves for controlling a descending speed of the stage part when descending, and the speed control valve. A switching valve for switching the descending speed of the stage section to two circuits each having a different speed by using at least one or more, and ON / OFF of the switching valve
Switching timing detecting means for detecting the switching timing of the stage, and the switching valve is switched according to the information of the detecting means when the stage part descends, and the descending speed until the printed board separates from the screen plate at the end of printing is determined by the printed board at the start of printing. A screen printing apparatus comprising: a control unit that slows the speed of ascending immediately below the screen plate and controls the descending speed faster after the printed circuit board is separated from the screen plate. 3. The switching timing detecting means is configured such that a reed switch is provided between the lifting strokes of the air cylinder, and the mounting position of the reed switch is varied so that the speed at which the printed circuit board is separated from the screen plate can be increased. The screen printing apparatus according to claim 1, wherein the range is adjustable. 4. A speed at which the printed circuit board is separated from the screen plate by changing the mounting position of the reed switch by providing a reed switch as switching timing detection means between the lifting strokes of the air-hydro cylinder. 3. The screen printing apparatus according to claim 2, wherein the range is adjustable. 5. The switching timing detecting means has a structure in which a proximity switch is provided on the upper surface of the stage section, and the distance between the screen plate and the proximity switch is measured and detected, and the range of speed until the printed circuit board is separated from the screen plate is set. The screen printing apparatus according to claim 1, wherein the screen printing apparatus is adjustable. 6. The screen printing apparatus according to claim 1, wherein a timer is provided as the switching timing detection means, and the range of speed until the printed circuit board is separated from the screen plate can be adjusted by time.