JP2601205B2 - High viscosity adhesive coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-viscosity adhesive applying apparatus for applying a high-viscosity adhesive to a substrate when connecting and fixing an electronic component to the substrate.

[0002]

2. Description of the Related Art Hitherto, a high-viscosity adhesive coating apparatus of this type is used for fixing small electronic components and supplying solder when mounting them on a printed circuit board. Such a high-viscosity adhesive coating apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-28487.
No. 6 and JP-A-62-176571. Japanese Patent Application Laid-Open No. Hei 4-284876 discloses that a container containing an adhesive is heated by a heater to improve the fluidity of the adhesive, and the nozzle for discharging the adhesive is cooled by an electronic cooler. It is disclosed that the stringing of the adhesive is prevented simultaneously with the ejection. In addition, Japanese Patent Laid-Open Publication No.
In both Japanese Patent Publication No. 76 and JP-A-62-176571, the temperature of the adhesive is detected by detecting the temperature of the container to control the discharge of the adhesive. However, since the detected temperature is different from the temperature of the adhesive actually discharged from the nozzle, the fixed amount of the adhesive cannot be discharged with high accuracy, and the stringing of the adhesive cannot be completely prevented. .

[0003] In recent years, circuit components and electronic components constituting electronic equipment have been increasingly miniaturized and miniaturized, and accordingly, various kinds of adhesives have been used for electronic components. Among them, conductive adhesives, which are high-viscosity adhesives, are generally used for connection and fixing between electronic components and circuits, and are mixed with a metal powder (Ag, Au) and a diluent based on an epoxy resin. , Viscosity is 10,000 cP
(Centipoise) and higher viscosity. The solder paste used for soldering also contains various solvents and has a high viscosity. Therefore, the application of such a high-viscosity adhesive uses a method in which electronic components are mounted by using a nozzle having a small diameter in order to control a minute amount of discharge, and further preheating the substrate in order to eliminate the stringing phenomenon. Conventionally, it was mainstream.

[0004]

However, this conventional high-viscosity adhesive coating apparatus requires a tunnel furnace or the like in order to warm a printed wiring board on which electronic components are mounted, thus increasing the size of the apparatus. . In addition, since a small amount of liquid must be ejected to a fine pattern portion, the nozzle must be made finer. Therefore, in the case of a highly viscous adhesive, the adhesive remains at the tip of the nozzle and hinders a constant amount of ejection. Furthermore, when the printed wiring board is warmed, the high-viscosity adhesive evaporates, and the pot life, which is the usable time, is significantly shortened, and the strength is deteriorated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-viscosity adhesive application apparatus which can perform a fixed amount discharge of an adhesive with high precision and can completely prevent stringing of the adhesive. .

[0006]

According to the present invention, there is provided a container containing a high-viscosity adhesive, a nozzle connected to a discharge port of the container and discharging the high-viscosity adhesive as a discharge adhesive. A heater provided on the outer periphery of the nozzle, a heater control circuit for supplying a drive current to the heater, and making the heater in a heat-generating state to apply heat to the discharge adhesive; and a heater control circuit provided near the heater, A temperature sensor that detects a temperature and outputs a temperature detection signal, wherein the heater control circuit responds to a temperature detection signal of the temperature sensor,
In order to control the temperature of the heater to a predetermined temperature, the drive current is supplied to the heater, and the heater and the temperature sensor are integrated as a micro-heater assembly. A high-viscosity-adhesive-applying device characterized by being detachable from the outer periphery is obtained.

[0007]

[0008]

Further, according to the present invention, a fixed amount of air is supplied to the container and is supplied to the container, and the high-viscosity adhesive in the container is discharged from the nozzle as the discharge adhesive by a predetermined amount. Thus, a high-viscosity-adhesive-applying device characterized by further including a discharge controller for performing the operation is obtained.

According to the invention, the discharge controller is connected to the discharge controller and the heater control circuit, and discharges the fixed amount of the high-viscosity adhesive from the nozzle as the discharge adhesive. If the discharge controller does not start the operation of discharging the next constant amount of the high-viscosity adhesive from the nozzle as the discharge adhesive even after a lapse of time, the drive current of the heater control circuit to the heater is controlled. A high-viscosity adhesive coating apparatus characterized by further including a nozzle clogging prevention circuit for stopping the supply operation is obtained.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 1, an apparatus for applying a high-viscosity adhesive according to one embodiment of the present invention has a syringe container 6 for containing a high-viscosity adhesive. The nozzle 7 is connected to a discharge port of the syringe container 6 (see FIG. 2), and discharges a high-viscosity adhesive as a discharge adhesive. Micro heater assembly 10
It has a heater provided on the outer periphery of the nozzle 7. The heater control circuit 50 switches the on-state switch 3 from the DC power supply 40.
Drive current received through the micro heater assembly 10
And the heater is heated to apply heat to the discharged adhesive.

The micro-heater assembly 10 further includes a temperature sensor (eg, a positive temperature coefficient thermistor) provided near the heater. This temperature sensor detects the temperature of the heater and outputs a temperature detection signal. The heater control circuit 50
In response to the temperature detection signal of the temperature sensor, a drive current is supplied to the heater to control the temperature of the heater to a predetermined temperature. The heater control circuit 50 is constituted by a temperature controller that can set the temperature arbitrarily. The heater control circuit 50 reads the resistance value of the temperature sensor of the micro heater assembly 10 by receiving the temperature detection signal, and reads the temperature of the heater of the micro heater assembly 10. Perform control. Specifically, the heater control circuit 50 has a time division processing circuit 60, and under the control of the time division processing circuit 60,
The supply of the drive current to the heater of the micro-heater assembly 10 and the measurement of the resistance value of the temperature sensor of the micro-heater assembly 10 are alternately performed, and the temperature of the heater of the micro-heater assembly 10 is constantly controlled.

The micro-heater assembly 10 has a heater and a temperature sensor integrated therein. As shown in FIG. 2, the micro-heater assembly 10 can be attached to and detached from the outer periphery of the nozzle 7.

In FIG. 1, the discharge controller 3 is connected to the syringe container 6 and supplies a certain amount of air (air blow) into the syringe container 6 by turning on the switch 2. A fixed amount of the high-viscosity adhesive is discharged from the nozzle 7 as a discharge adhesive. In detail, the discharge controller 3 has an air pressure reducing regulator 4 for controlling the air pressure supplied to the syringe container 6 and a discharge timer 5 for determining a supply time of the air supplied to the syringe container 6. When the switch 2 is turned on, the air is supplied to the syringe container 6 at the air pressure controlled by the air pressure reduction controller 4 over the time determined by the discharge timer 5. The discharge controller 3 supplies a timeout signal generated when the discharge timer 5 measures a predetermined time to the nozzle clogging prevention circuit 70, and generates a start signal when the first switch 2 is turned on. This is given to the nozzle clogging prevention circuit 70.

The nozzle clogging prevention circuit 70 is for preventing the nozzle 7 from being clogged by heating for a long time.
The nozzle clogging prevention circuit 70 is connected to the ejection controller 3 and the heater control circuit 50, and even after a certain period of time has elapsed after the ejection controller 3 ejected a fixed amount of the high-viscosity adhesive from the nozzle 7 as the ejection adhesive. Discharge controller 3
Does not start the operation of discharging the next fixed amount of the high-viscosity adhesive from the nozzle 7 as the discharge adhesive, the switch 30
Is turned off, and the operation of the heater control circuit 50 to supply the driving current to the heater is stopped. More specifically, the nozzle clogging prevention circuit 70 first turns on the switch 30 in response to a start signal generated by the ejection controller 3 when the first switch 2 is turned on. Then, the nozzle clogging prevention circuit 70 is connected to the ejection controller 3.
When the time-out signal generated by the discharge timer 5 is received, the built-in timer 20 is caused to perform a time counting operation for a fixed time. If the next start signal indicating the ON state of the first switch 2 is received from the ejection controller 3 before the end of the time counting operation for the predetermined time, the built-in timer 20 is reset. When the built-in timer 20 finishes the time counting operation for a certain period of time without receiving the next start signal from the ejection controller 3 and outputs a timeout signal, the nozzle clogging prevention circuit 70 switches the switch 30 until the next start signal is received. Is turned off, and supply of the drive current from the DC power supply 40 to the heater control circuit 50 is stopped. As a result,
The operation of supplying the drive current from the heater control circuit 50 to the heater of the micro-heater assembly 10 is stopped.

Next, the general operation of the high-viscosity adhesive coating apparatus shown in FIG. 1 will be described.

The high-viscosity adhesive filled in the syringe container 6 is discharged in a fixed amount for a predetermined time according to the conditions set by the discharge controller 3. At this time, the nozzle 7 is heated to about 50 ° C. by the heater of the micro heater assembly 10, the viscosity of the adhesive is reduced from 10,000 cP to about 2,000 cP, and even the fine nozzle 7 discharges a certain amount of the adhesive. And a small amount of coating can be performed. Further, the high-viscosity adhesive discharged onto the printed wiring board is rapidly cooled to have a high viscosity, thereby eliminating the threading phenomenon of the coating between the nozzle 7 and the printed wiring board.

Further, in order to prevent the nozzle 7 from being clogged by heating for a long time, the nozzle clogging prevention circuit 70 is provided after the discharge controller 3 discharges a fixed amount of the high-viscosity adhesive from the nozzle 7 as the discharge adhesive. When the discharge controller 3 does not start the operation of discharging the next fixed amount of the high-viscosity adhesive as the discharge adhesive from the nozzle 7 even after the predetermined time has elapsed, the switch 30 is turned off, and the heater control circuit 50 is turned off. The operation of supplying the drive current to the heater is stopped.

Referring to FIG. 2, nozzle 7 is made of metal, and syringe container 6 is made of a heat insulating material such as plastic, and has a structure which is not affected by heat from nozzle 7 and is preheated. Evaporation of the dilution solvent contained in the high-viscosity adhesive can also be prevented. Further, since the micro-heater assembly 10 is small and lightweight, it can be easily attached to and detached from the nozzle 7, and can be easily applied to the movable portion of the automation device.

[0021]

As described above, in the high-viscosity adhesive applying apparatus according to the present invention, the heater is attached to the nozzle connected to the discharge port of the container containing the adhesive, and the discharged adhesive is heated by the heater. The feature is that the viscosity of the adhesive is lowered just before it is discharged from the nozzle, thereby enabling high-precision coating without quantitative threading, and miniaturization of the device. is there.
Moreover, in the high-viscosity adhesive application device according to the present invention, a temperature sensor is provided in the nozzle, the temperature of the adhesive actually discharged from the nozzle is detected, and the temperature of the heater is controlled.
It is possible to perform the fixed amount discharge of the adhesive with higher accuracy, and it is possible to completely prevent stringing of the adhesive.

[Brief description of the drawings]

FIG. 1 is a block diagram of a high-viscosity adhesive applying apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the assembly of the syringe container, nozzle and micro heater of FIG. 1;

[Explanation of symbols]

 2 Switch 3 Discharge controller 6 Syringe container 7 Nozzle 10 Micro heater assembly 30 Switch 40 DC power supply 50 Heater control circuit 70 Nozzle clogging prevention circuit

Claims (3)

(57) [Claims] 1. A container for accommodating a high-viscosity adhesive, a nozzle connected to a discharge port of the container and discharging the high-viscosity adhesive as a discharge adhesive, a heater provided on an outer periphery of the nozzle, A heater control circuit for supplying a drive current to the heater to heat the heater by causing the heater to generate heat; and a heater control circuit provided near the heater for detecting a temperature of the heater and outputting a temperature detection signal. The heater control circuit supplies the drive current to the heater in order to control the temperature of the heater to a predetermined temperature in response to a temperature detection signal of the temperature sensor. A high-viscosity adhesive coating apparatus, wherein the heater and the temperature sensor are integrated as a micro-heater assembly, and the micro-heater assembly is detachably attached to an outer periphery of the nozzle. 2. A discharge controller coupled to the container, supplying a constant amount of air into the container, and discharging the high-viscosity adhesive in the container by a predetermined amount from the nozzle as the discharge adhesive, The high viscosity adhesive application device according to claim 1, further comprising: 3. The method according to claim 1, wherein the discharge controller is connected to the discharge controller and the heater control circuit, and the discharge controller discharges the fixed amount of the high-viscosity adhesive from the nozzle as the discharge adhesive. When the discharge controller does not start the operation of discharging the next fixed amount of the high-viscosity adhesive from the nozzle as the discharge adhesive, the operation of supplying the drive current to the heater of the heater control circuit is stopped. 3. The high-viscosity adhesive applying apparatus according to claim 2, further comprising a nozzle clogging prevention circuit.