JPH04309459A - Solder paste applying device - Google Patents

Abstract

PURPOSE:To offer the solder paste applying device which can execute stably soldering by applying solder paste by making its discharge quantity constant. CONSTITUTION:In a cylinder-like vessel 10 for containing solder paste 1, a nozzle 3 is installed in a conical bottoms part, and in the inside of the vessel 10, a pressure plate 11 is provided so as to be freely slidable through an O ring 12. Also, to the upper part of the outside periphery of the vessel 10, a holding part 14 having a bearing 13 is screwed and attached, and to its upper part, a motor supporting part 15 is fixed. As for the motor supporting part 15, a driving motor 16 is installed in the inside, and a recessed part 17 is provided on both ends of the lower part. Moreover, to a shaft 18 of the motor 16, a rotation axis 20 having an inside screw 19 is fixed, and a connecting shaft 22 having an outside screw 21 screwed to this inside screw 19 is provided. The lower end of the connecting shaft 22 is screwed and attached to the pressure plate 11, and a projecting part 23 is provided in a position corresponding to the recessed part 17 of the motor supporting part 15, supported axially by a bearing 13, and also, subjected to rugged fitting by the recessed part 17 and the projecting part 23 and slides vertically. In such a state, when the motor 16 is driven, the torque of the rotation axis 20 is converted to pressing force by a sliding action of the screw part and the rugged fitting part, and the solder paste 1 is discharged.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder paste applicator capable of discharging solder paste at a constant rate.

0002

2. Description of the Related Art In recent years, solder paste applicators have been widely used for dot soldering and line soldering on printed circuit boards of electronic components.

Conventionally, this type of solder paste applicator has a configuration as shown in FIG. The configuration will be explained below with reference to the drawings. As shown in the figure,
A container 2 containing a solder paste 1 has a conical bottom equipped with a nozzle 3, and a cylindrical top surface equipped with a lid plate 5 having an air supply pipe 4. Further, a plunger 6 that slides up and down inside the container 2 is provided, and compressed air is introduced from the air supply pipe 4 by a blowing means 7. The blowing means 7 includes a pressurizing pump 7a, an on-off valve 7b for switching air passages, and a controller 7c. 8 is a printed circuit board.

The operation of the solder paste applicator constructed as described above will be explained below. Solder paste 1 is stored in a container 2, covered with a plunger 6, and compressed air is introduced by an air blower 7. 2
The solder paste 1 inside is pressurized and discharged from the nozzle 3 and applied to the substrate 8.

FIG. 5 shows the relationship between the pressurizing conditions of the air blowing means 7 and the amount of solder paste 1 discharged. That is, (
a) The controller 7c opens and closes the on-off valve 7b (T
1, T2, T3, T4), the operating times become t1 and t2. (b) shows the distribution of pressures P1 and P2 inside the container 2 when the air valve is opened and closed. (c) is nozzle 3
These are the discharge amounts G1 and G2 of the solder paste 1 discharged from.

[0006]

However, in the conventional configuration described above, variations occur in the operating time (t1, t2) of the on-off valve 7b and the pressure (P1, P2) in the container 2, so that the discharge amount of the solder paste 1 ( G1, G2) could not be kept constant, which caused a problem in that soldering defects occurred during soldering.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a solder paste applicator that can stably perform soldering by keeping the amount of solder paste constant.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cylindrical container containing solder paste, a nozzle attached to an end of the container, and a nozzle that can be slid freely inside the container. a pressurizing plate provided in the container, a holding part having a bearing provided in the upper part of the container, a motor support part fixed to this holding part and having a recessed part, a motor inserted in this motor support part, A rotating shaft having an internal thread fixed to the shaft, and an external thread screwed to the internal thread,
and a connecting shaft having a convex portion that engages with the concave portion,
The connecting shaft is configured to slide on a threaded portion and an uneven portion to convert the rotational torque of the motor into thrust pressure, and press the pressure plate to discharge solder paste. A control device is provided, and the control device controls the drive amount of the motor to discharge a fixed amount of solder paste.

[0009]

[Operation] In the above configuration, the connecting shaft slides on the threaded portion and the uneven portion, converts the rotational torque of the motor into thrust pressure, presses the pressure plate and discharges the solder paste, and also controls the control device. Since the drive amount of the motor is controlled by , a fixed amount of solder paste is discharged.

0010

Embodiment An embodiment of the present invention will be described below with reference to FIG. In this embodiment, the same components as those shown in the above-mentioned conventional example are given the same reference numerals, and the explanation thereof will be omitted. As shown in the figure, a cylindrical container 10 containing solder paste 1 has a nozzle 3 attached to its conical bottom, and a pressure plate 11 is slidably provided inside the container 10 via a ring 12. ing. Further, a holding part 14 having a bearing 13 is screwed onto the upper outer circumference of the container 10, and a motor support part 15 is fixed to the upper part. The motor support part 15 is equipped with a drive motor 16 inside,
It has recesses 17 at both ends of the lower part. Further, a rotating shaft 20 having an internal thread 19 is fixed to the shaft 18 of the motor 16, and a connecting shaft 22 has an external thread 21 that is screwed into the internal thread 19.
has been established. The lower end of the connecting shaft 22 is screwed onto the pressure plate 11, and a convex portion 2 is provided at a position corresponding to the concave portion 17 of the motor support portion 15.
3, and is pivotally supported by a bearing 13 and slid up and down by engaging the concave and convex portions of the concave portion 17 and the convex portion 23. 24 is a universal joint provided in the middle of the connecting shaft 22 to absorb eccentricity during assembly. Furthermore, a tacho generator 25 and an encoder 26 for detecting the position (arrow Z) of the pressure plate 11 are inserted into the upper shaft end of the motor 16. Further, 27 is a pressure sensor, which outputs a signal when it contacts the solder paste 1 with a predetermined pressure, identifies whether or not the pressure plate 11 and the solder paste 1 are in contact, and is connected to the sensor circuit 28. ing. 29 is a control device that controls the motor 16. Then, when the motor 16 is driven,
The torque of the rotating shaft 20 is converted into a pressing force by the sliding action of the threaded part and the concave-convex fitting part, and the pressure plate 11 is applied to the solder paste 1.
is pressurized and a predetermined amount is discharged from the nozzle 3.

FIG. 2 is a block diagram of the control device section of the present invention. As shown in the figure, the control device 29 includes the servo amplifier 3
0, a robot controller 31, and a keyboard group 32 for input, and inputs signals from a sensor circuit 28. The robot controller 31 includes a D/A converter 33, a deviation counter 34, a servo controller 35, a sequence controller 36, and a microcomputer 37. 38 is a speed detection loop, and 39 is a position detection loop.

The pressure detected by the pressure sensor 27 is detected by the pressure sensor circuit 28 and amplified by the amplifier 40.
A comparison is made to see if the pressure is above a predetermined pressure, and the output after the comparison is input to the next stage. The A/D converter 42 converts it into a 0,1 signal and reads it to the microcomputer 37. Note that the integral value of the output of the encoder 26 may be used as the speed detection loop 38 instead of the tacho generator 25. Further, the servo amplifier 30 is a DC power source that drives the motor 16, and the rotation speed and rotation direction are determined by the output of the D/A converter 33. The D/A converter 33 converts the digital value of the deviation counter 34 into an analog value. The deviation counter 34 counts the number of pulses that is the difference between the number of position pulses at the specified Z position (Z position on the program) and the number of position pulses of the encoder 26 during movement and rotation. The servo controller 35 sequentially outputs Z position pulses on the program, and the sequence controller 36 controls the entire sequence.

A time chart for coating in the above configuration will be explained with reference to FIG. In other words, the horizontal axis represents time, T0, T1, T2, T3, T4, T5, T6, T.
7, T8 indicates time on time t. The scale indicated by the arrow Z indicates the Z position of the pressure plate 11 in the direction in which the solder paste 1 is discharged from the container 10, and PZ0 is the initial solder upper position (discharge start point or coating start point). A is correct, B
indicates the amount of movement per movement in the negative Z-axis direction. T0 and T1 are the origin search positions, T2 is the detection point of the pressure sensor 27, and T3 and T4 are the first discharge (coating). repeat. Therefore, the amount of progress for the second discharge is (A
-B), and the discharge volume V=(A-B)×π×R2(π
is pi and R is the radius of the container 10).

In this embodiment, a servo motor is used as the drive source, but a pulse motor may be used to determine the number of pulses depending on the amount of discharge per discharge and rotate with that number of pulses. Alternatively, the rotating shaft 20 may be omitted and the internal thread 19 may be provided directly on the shaft 18 of the motor 16. Further, it is also possible to apply resins, liquids, sealants, etc. other than the solder paste 1.

[0015]

As is clear from the above embodiments, the solder paste applicator of the present invention includes a cylindrical container for containing solder paste, a nozzle attached to the end of the container, and a cylindrical container that accommodates a solder paste. A pressurizing plate provided movably, a holding part having a bearing provided on the upper part of the container, a motor support part fixed to this holding part and having a recessed part, a motor inserted into this motor support part, and this A rotating shaft having an internal thread fixed to the shaft of the motor, and a connecting shaft having an external thread screwed to the internal thread and a convex portion that engages with the recess, the connecting shaft It slides on the threaded part and the uneven part, converts the rotational torque of the motor into thrust pressure, presses the pressure plate, and discharges the solder paste. With this configuration, the amount of solder paste discharged can be reduced. It can be applied at a constant rate to achieve stable soldering.

[Brief explanation of drawings]

FIG. 1 (a) A cross-sectional view of a solder paste applicator according to an embodiment of the present invention. (b) A cross-sectional view taken along the line A-A in FIG. 1 (a).

[Figure 2]
Block circuit diagram of the control unit of the solder paste applicator

[Figure 3] Coating time chart of the solder paste coating device

[Figure 4] Cross-sectional view of a conventional solder paste applicator

[Figure 5
] Application time chart of the same solder paste application device

[Explanation of symbols]

1 Solder paste 3 Nozzle 10 Container 11 Pressure plate 13 Bearing 14 Holding part 15 Motor support part 16 Motor 17 Recessed part 19 Internal thread 20 Rotation axis 21 External thread 22 Connecting shaft 23 Convex part

Claims (2)

[Claims] 1. A cylindrical container containing solder paste, a nozzle attached to an end of the container, a pressure plate slidably provided inside the container, and a bearing provided at the top of the container. a motor support part fixed to the holding part and having a concave part, a motor inserted into the motor support part, a rotating shaft having an internal thread fixed to the shaft of the motor, a connecting shaft having an external thread screwed onto the screw and a convex portion that engages with the recessed portion, and the connecting shaft slides on the threaded portion and the uneven portion to thrust the rotational torque of the motor. A solder paste application device that converts pressure into pressure, presses the pressure plate, and discharges solder paste. 2. The solder paste application device according to claim 1, further comprising a control device for controlling the amount of rotation of the motor, the control device controlling the amount of drive of the motor to discharge a fixed amount of solder paste.