JP2744030B2 - Screen printing machine - Google Patents

Description

The present invention relates to a screen printing machine that applies cream solder onto a printed circuit board by moving a squeegee through a vertically movable screen plate.

(B) Conventional technology This type of screen printing machine is disclosed in Japanese Patent Application Laid-Open No. 63-120650.

In this prior art, the printing screen is adjusted by moving up and down using a lifting handle while measuring the gap between the printing object fixing stage and the printing screen with an air micrometer.

(C) Problems to be Solved by the Invention However, in the above-mentioned prior art, since the operator turns the lifting handle by hand while measuring with an air micrometer, it takes time for adjustment and the reproducibility of the adjustment is the same every time. There is a disadvantage that it must not.

Therefore, an object of the present invention is to reduce the time required for adjustment and improve the reproducibility of adjustment.

(D) Means for Solving the Problems Accordingly, the present invention raises and lowers the screen plate in a screen printing machine that applies cream solder onto a printed circuit board by a moving operation of a squeegee via a screen plate that can be raised and lowered. Driving means, an origin detection sensor for detecting a reference point for ascending and descending the screen plate, storage means for storing data representing a gap between the screen plate and the board, and counting means for counting the ascending and descending distance of the screen plate,
Control means for controlling the driving means so that a gap between the screen plate and the substrate becomes data stored in the storage means based on information from the origin detection sensor and information from the counting means. .

(E) Operation The control means drives the driving means to lower the screen plate, and when the origin detection sensor detects the reference point, stops the driving means and stops the screen plate at the reference point for ascending and descending. Thereafter, the control means drives the driving means to raise the screen plate, and when the counting means counts the data indicating the gap between the screen plate and the substrate stored in the storage means, stops the driving means and stops the raising of the screen plate. .

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, (1) is a screen printing machine of the present invention. (2) is a printed circuit board which is a printing substrate, on which cream solder is applied in a desired pattern so that electronic components are mounted on the upper surface. Reference numeral (3) denotes a mounting table on which the substrate (2) is mounted and the substrate (2) is suction-mounted on the upper surface by a vacuum pump (not shown). (4A) (4
B) supports the substrate (2) at the application position, and is a support table movable by a cylinder (not shown).

(5) is a screen, which comprises a screen plate (6) formed in a desired circuit pattern and a screen frame (7) surrounding the plate (6). (8) is a squeegee for moving the screen plate (6) of the screen (5) horizontally while pressing the screen plate (6) against the substrate (2) to apply the cream solder on the screen plate (6) onto the substrate (2). is there.

In FIG. 3, reference numeral (10) denotes an AC motor as driving means for moving the screen up and down.

(11) is a bevel gear axially mounted on the rotating shaft of the motor (10), and (12) is a bevel gear axially mounted on the connecting rod 1 (13) orthogonal to the rotating shaft of the motor (10). However, since the bevel gears (11) and (12) are engaged with each other, the connection rod 1 (13) is rotated by the rotation of the motor (10).

(14) and (15) are bevel gears pivotally mounted on the connecting rod 1 (13).
7) is engaged with the bevel gear (15) and is axially mounted on the end of the connecting rod 3 (19). The rotation of the connecting rod 1 (13) is orthogonal to the connecting rod 1 (13) by these bevel gears. To the connecting rod 2 (18) and the connecting rod 3 (19).

Reference numerals (20) and (21) denote worms pivotally connected to the connecting rod 2 (18), and (22) and (23) denote worms pivotally mounted to the connecting rod 3 (19). (24), (25), (26), and (27) are worm wheels that are engaged with the worms (20), (21), (22), and (23), respectively, and the rotation thereof is vertical.

In FIG. 2, reference numerals (30) and (31) denote jack shafts on which worm wheels (24) and (25) are pivotally mounted at the lower ends and screw portions are provided at the upper ends, respectively. ) (25), but each bearing (3
3) Received in (34).

(32) is a base to which the bearings (33) and (34) are fixed. (35) is a pedestal on which nuts (40) and (41) are installed. The nuts (40) and (41) have their screw holes screwed with the jack shafts (30) and (31), respectively.
The (31) rotates to move up and down, and accordingly the pedestal (35) moves up and down.

(42) and (43) are stud bolts fixed on the pedestal (35) and supporting the support plates (44) and (45), respectively, for adjusting the height of the support plates (44) and (45). it can. The support plates (44) and (45) support the screen (5) by supporting the screen frame (7).

The upper part of the worm wheels (26) and (27) has the same structure as described above. The screen frame (7) is supported at four points and the screen plate (6) is adjusted to be horizontal. The gap between the screen plate (6) and the substrate (2) (hereinafter referred to as the screen gap) is adjusted by the rotation of the motor (10).

(46) is a slit plate with two upper and lower notches,
(47) means that the screen plate (6) is lowered and the substrate (2)
The lower limit for detecting the lower limit of the screen plate (6) by passing the lower cutout of the slit plate (46) to prevent the motor (10) from continuing to rotate and overrun even when it abuts on the screen plate (6). Reference numeral (48) denotes an upper limit detection sensor for detecting the upper limit by transmitting light through the upper cutout of the slit plate (46) so as to prevent the screen plate (6) from rising excessively and overrunning.

(49) is a disk having only one cutout on its outer periphery toward the center of the circle and fixed concentrically to the jack shaft (30), and (51) is a disk (49) Is a rotation origin detection sensor that detects the rotation origin by transmitting light through the notch. The lower limit detection sensor (47) detects the lower limit and the rotation origin detection sensor (51) detects the position at which the screen gap becomes zero, that is, the origin which is the reference point for ascending and descending.
Is when the rotation origin is detected.

(50) is a disk concentrically fixed to the jack shaft (30) having notches at regular intervals on its outer periphery toward the center of the circle, and (52) is a disk of the disk (50). A pulse detection sensor that is turned ON each time light passes through the notch.

In FIG. 4, reference numeral (55) denotes an operation unit having a ten-key (56), a cursor key (57), and a SET key (58), which stores data used during automatic operation in the RAM (64). A teaching key (59) for setting a mode, an automatic key (60) for setting a mode for performing automatic operation, and an operation key (61) for starting automatic setting of a screen gap are also provided.

(63) is an interface and an error indicator (66),
CRT (67), motor (10), lower limit detection sensor (47), upper limit detection sensor (48), rotation origin detection sensor (51), pulse detection sensor (52), operation unit (55), CPU (66) Connected.

(64) is a RAM for storing various data used during automatic operation such as data for automatically setting a screen gap (hereinafter referred to as screen gap data) and a subtracted value of the screen gap data, and (65) relates to a screen gap adjusting operation. ROM for storing programs.

Reference numeral (66) denotes a CPU, a control function relating to storing various data in the RAM (64) in response to the operation unit (55), and a RAM.
AC based on the data in (64) and the signal from each sensor
It has a motor (10) control function and a subtraction counter function. The CPU (66) having a subtraction counter function and the RAM (6) for storing a subtraction value of the screen gap data.
4), the disk (50) and the pulse detection sensor (52) constitute a counting means for counting the vertical distance.

Next, the operation of storing the screen gap data in the RAM (64) will be described.

First, when the teach key (59) is pressed, the TEAC shown in FIG.
The H SELECTION screen appears on the CRT (67). On this screen, NC D
Move the cursor to ATA INFORMATION with the cursor key (57) and press the SET key (58).
The INFORMATION screen appears. When a board number corresponding to the board (2) is selected on this screen and the SET key is pressed, a SETUP DATA EDIT screen shown in FIG. 7 is displayed. On this screen, move the cursor to SCREEN DISTANCE DATA and enter data corresponding to the board (2) using the numeric keypad (56). As this data, for example, a number from 1 to 100 representing 1 mm can be selected. Thus, the screen gap data is stored in the RAM (64).

SCREEN DISTANC of item 6 on this SETUP DATA screen
E determines whether the screen gap is automatically set or not. If the data is 1, the automatic setting operation is performed. If the data is 0, the motor (10) does not rotate and the automatic setting operation is not performed.

The storage operation of the screen gap data as described above can be performed for several types of substrates.

 The operation of the above configuration will be described below.

First, the teach key (59) is pressed to call the PROGRAM CHANGE screen shown in FIG. 8 via the TEACH SELECTION screen (FIG. 5). Select the desired board number here and press the operation key (6
Press 1). Then, the automatic setting operation is started in accordance with the flowchart of FIG. 9, but the screen gap data is taken into the CPU (66), and if both the rotation origin detection and the lower limit detection are not performed at the same time, the AC is returned for the origin return.
The motor (10) is rotated so that the screen (5) descends.

Here, the rotation of the AC motor (10) is controlled by the bevel gear (11) (1
2), connecting rod 1 (13), bevel gear (14) (15) (16)
(17), connecting rod 2 (18) connecting rod 3 (19), worm (2
0) (21), (22) (23), worm wheel (24) (2
5), (26) and (27) are transmitted in that order, and the jack shaft (33) (3
4) and the jack shaft at the rear in FIG. 2 is rotated, whereby the nuts (40) (41), the pedestal (35), the stud bolts (42) (43), the support plates (44) (45), etc. The screen (5) placed on them is lowered and lowered.

The screen (5) descends, but if only the lower limit detection sensor (47) performs the detection operation even when the origin is reached, an abnormality is displayed on the abnormality indicator (66) and the AC motor (10)
Stop the rotation of. When the screen (5) reaches the origin and both the rotation origin detection and the lower limit detection are performed, the AC motor (10) temporarily stops and then starts rotating in the direction in which the screen gap widens. When the screen (5) continues to rise and the upper limit detection sensor (48) detects the upper limit, an error is displayed on the error indicator (66) and the rotation of the AC motor (10) is stopped.

Normally, when the screen (4) rises, the disk (50) attached to the jack shaft (30) rotates, and the pulse detection sensor (52) passes through notches provided at equal intervals. Each time a pulse is generated, the CP has a subtraction counter function
The U (66) subtracts one from the screen gap data in the RAM (64) and stores the subtracted value in an area in the RAM (64) different from the area where the screen gap data is stored. For example, if the screen gap data is 10, a subtraction value of 9 is stored. When the disk (50) is further rotated and the next pulse is generated, one is further subtracted. This subtraction is repeated until the subtraction value becomes zero. When the subtraction value becomes 0, the CPU (66) issues an interface (6
3) Stop the rotation of the AC motor (10) via.

Thus, the screen gap is set according to the screen gap data.

When the automatic operation is started by pressing the automatic key (60) in this state, the substrate (2) is mounted on the mounting table (3) and the support tables (4A) (4B) as shown in FIG. Then, the squeegee (8) is lowered by a cylinder (not shown) and moves rightward in FIG. 1 by horizontal moving means (not shown) while pressing the screen plate (6) to remove the cream solder on the screen plate (6). Coating on substrate (2).

(G) Effects of the Invention As described above, according to the present invention, the time required for adjusting the gap between the screen plate and the printed board is reduced, and the reproducibility of the adjustment is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a screen printing machine to which the present invention is applied, partly in section, FIG. 2 is a front view of a main part of the present invention, and FIG.
FIG. 4 is a block diagram relating to the control of the present invention, FIG. 5 is a diagram of a TEACH SELECTION CRT screen, FIG. 6 is a diagram of an NC DATA INFORMATION CRT screen, and FIG. DATA EDIT CRT screen, Fig. 8 is PROGRAM CHANG
FIG. 9 is a flowchart showing an automatic setting operation of the screen gap. (10) ... motor, (47) ... lower limit detection sensor, (49)
… Disc, (50)… Disc, (51)… Rotation origin detection sensor, (52)… Pulse detection sensor, (64)… RAM,
(66) CPU.

Claims (1)

(57) [Claims] 1. A screen printing machine for applying cream solder onto a printed circuit board by moving a squeegee through a vertically movable screen plate, a driving means for raising and lowering the screen plate, and a lifting device for raising and lowering the screen plate. An origin detection sensor for detecting a reference point, storage means for storing data representing a gap between the screen plate and the substrate, counting means for counting a vertical distance of the screen plate, information from the origin detection sensor and the count A screen printing machine provided with control means for controlling the driving means so that a gap between the screen plate and the substrate becomes data stored in the storage means based on information from the means.