JPH03188966A - Adhesive applicator - Google Patents

Abstract

PURPOSE:To quantitatively apply an adhesive with high precision of coating amt. resolving power by forming a part of the passage extending from an adhesive tank to an orifice or providing a piezo element for vibrating a part constituting the passage and a pulse power source connected to the element. CONSTITUTION:A pulse voltage is impressed on the piezo element 4, hence the element 4 is minutely vibrated, and an adhesive 9 is excited by the minute pressure. The pressure wave is transmitted toward an adhesive tank 14 and an orifice 2, and the surface of the adhesive 9 is bulged when the pressure wave reaches the orifice 2 which is a free end. At this time, when a sufficiently high pulse voltage is impressed with respect to the viscosity of the adhesive 9, the discharging power exceeds the power to pull the adhesive inward, and the adhesive 9 is flown as droplets 19 to the surface to be coated, and the surface is coated. Since the adhesive 9 is micronized in this way, the adhesive is quantitatively applied with high precision of coating amt. resolving power irrespective of the state of the tip surface of the applicator and surface to be coated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive applicator and a pasting device using the adhesive applicator.

[Conventional technology]

The method of applying adhesive using a conventional adhesive applicator is to discharge adhesive from the large end and bring it into contact with the surface to be applied.

(Drop coating method) Another method is JP-A-60-149
This is a method (droplet application method) in which the adhesive is formed into droplets and applied by means such as mixing air into the adhesive discharged from an orifice. However, in the conventional droplet coating method, the amount of droplets ejected is 1. Ox 10-1m
When it is about m5, it is impossible to eject one drop at a time, and it is necessary to eject it in the form of a spray, which makes it difficult to apply a small amount, and there is a large variation in the amount of ejection from one drop to another. Therefore, the coating amount is 1. A droplet coating method is used to apply a small amount of Ox 10-'mm'. However, even if the above-mentioned discharge amount can be obtained with the droplet coating method, since the coating is applied by contacting the surface, there is a large disparity between the amount remaining at the tip of the device and the amount actually applied. [Problems to be solved] In the case of a conventional drop contact type adhesive application device, a minimum discharge amount of adhesive of about 1.0×10'mm' can be obtained. However, when applying the discharged adhesive in contact with each other, the amount of adhesive applied to the coating surface and the amount remaining at the tip of the device are affected by the interfacial adhesive force between the surface of the coating surface and the surface of the tip of the device. Even if the accuracy of the adhesive is good, there is a large variation in the amount actually applied.The purpose of the present invention is to reduce the amount of adhesive applied by making it into fine droplets and applying it, regardless of the conditions of the tip surface of the device and the surface of the application surface. Quantitative resolution5. It is an object of the present invention to provide an adhesive coating device capable of applying a quantitative amount with high precision at Ox 10-'mm5 or less.

[Failure to solve the problem]

An adhesive tank and an orifice are provided so as to form part of a flow path from the adhesive tank to the orifice.
Alternatively, a piezo element is provided to vibrate the parts constituting the flow path, and a pulse wave power source connected to the piezo element is provided.Furthermore, in the above device, an orifice is provided at the center of the cylindrical piezo element. In addition, an orifice is provided at the center of a hollow spherical piezo element.
In the above device, the rise time of the applied voltage by the pulse wave power source was made shorter than the response time of the piezo element.

In addition, in the above device, the voltage applied by the pulse wave power source is lowered even lower than the initial voltage when the voltage drops. To set up the mechanism, an electrode was provided in the flow path that could conduct with the adhesive, an electrode was provided at a position facing the orifice, and a power source was provided to apply a high voltage between the two electrodes.

Furthermore, in order to be able to apply a hot-melt adhesive, we use a hot-melt adhesive that is solid at room temperature and becomes liquid when heated, and a heater is installed around the outer periphery of the adhesive tank, inside the adhesive tank, or in the flow path. Established.

In addition, a ring-shaped electrode (charged electrode) is placed in the adhesive applicator so that the orifice is near the center of the ring, and two electrodes (deflection electrodes) are placed opposite each other across the path of the droplet in the direction in which the droplet travels. has been established.

Further, the adhesive application device was provided with a work supply device, a carry-out device, and a pasting position setting device.

[Effect]

By adopting the configuration as defined in claim 1 of the present invention, the following effects can be obtained. In other words, when a pulse voltage is applied to a piezo element, the piezo element vibrates minutely,
The adhesive can be excited by minute pressure. The pressure wave propagates toward the adhesive tank and toward the orifice. When the busy pressure wave reaches the free end of the orifice, the adhesive liquid level rises.

At this time, if a sufficiently high pulse voltage is applied to the viscosity of the adhesive, the force of ejection will outweigh the force of pulling it back inside due to surface tension, and the adhesive will fly as droplets and be applied. By adopting the structure according to claim 2 of the present invention, the following effects can be obtained. That is, in claim 1, if a cylindrical piezo element is used, the pressure distribution inside the cylinder when the adhesive is excited by a minute pressure will be highest at the center and lowest near the wall surface. From this, pressure can be used efficiently by providing the orifice at the center where the pressure is highest. Furthermore, when a pulse voltage is applied to a hollow spherical piezo element, the piezo element contracts in the circumferential direction.The pressure distribution within zero is highest at the center and lowest near the wall surface.

From this, if the orifice is provided at the center where the pressure is highest, pressure can be used more efficiently.

By adopting the structure of claim 3 of the present invention, the following effects can be obtained. That is, since the rise time of the applied voltage can be shortened to the extent that the reaction time of the piezo element is shortened, the flow of adhesive in the piezo element during displacement of the piezo element can be reduced, and a higher pressing force can be obtained.

By adopting the structure of claim 4 of the present invention, the following effects can be obtained. That is, when a high viscosity liquid is made into fine droplets, the droplets become easier to pull on a thread. By lowering the voltage below the initial voltage during the voltage drop and displacing the piezo element in the opposite direction to that during pressurization, excess threads generated during droplet generation can be sucked back into the nozzle.

By adopting the configuration as defined in claim 5 of the present invention, the following effects can be obtained. That is, when a pulse current is passed through the micro heating mechanism, the adhesive near the heating mechanism is vaporized and micro bubbles are generated.

As a result, the adhesive is pushed away toward the orifice and toward the tank, and the adhesive liquid level rises on the orifice side.

At this time, if a sufficiently large pulse current is applied relative to the viscosity of the adhesive, the adhesive will fly in the form of droplets, reach the surface to be coated, and be coated.

By adopting the configuration as defined in claim 6 of the present invention, the following effects can be obtained. That is, when a pulsed electrostatic field is applied between the adhesive and the electrode, the adhesive flies in the form of droplets due to electrostatic attraction, reaches the surface to be coated, and is coated.

According to the configuration of claim 7 of the present invention, by melting the hot-melt adhesive with a heater, the hot-melt adhesive can be applied in fine droplets with a droplet diameter of several hundred μm or several tens of μm. In addition, by making it possible to apply hot-melt adhesives, volatile components do not evaporate because the adhesive is solid at room temperature, and it always becomes liquid when heated, so if it is not used for a long time. However, clogging of the orifice due to hardening of the adhesive can be prevented. By adopting the configuration according to claim 8 of the present invention, the following effects can be obtained. When the liquid level rises, for example, if a positive voltage is applied to the charged electrode, the adhesive is dielectrically polarized and the liquid level is negatively polarized. In this state, the droplets separated from the liquid surface and generated are negatively charged. When the droplet is passed between deflection electrodes to which a voltage is applied, the droplet is deflected. By controlling the coating position by electrically deflecting the droplets, it has become possible to easily and precisely control the coating position. Also,
This makes it possible to perform line coating on 9 surfaces.
With the pasting device according to claim 9 of the present invention, not only highly accurate application but also highly accurate pasting can be performed automatically.

〔Example〕

<Embodiment 1> FIG. 1 is a sectional view of an embodiment according to claim 1 of the present invention. An adhesive 9 is contained in an adhesive tank 14. A filter 15 is provided in the middle and upper part of the adhesive tank. A cylindrical piezo element 4 is installed between the adhesive tank 14 and the orifice 2.
(Length: 10mm). Also, inner diameter 1
A 00μm orifice 2 is press-fitted into the base 1,
The center of the orifice 2 and the central axis of the cylindrical piezo element are arranged so as to coincide with each other. This piezo element 4 is polarized inside and outside. The inner electrode can be removed from the outside up to a distance of 2 mm from one end of the piezo element 4. The piezo element 4 is arranged so that the side with the inner electrode protruding outward is on the adhesive tank side. @The inner electrode is connected to the lead wire 8-
It is taken from A. ◎The outer electrode is taken from lead wire 8-B. Furthermore, an O-ring 6 is provided at the top of the piezo element 4 in the figure, and a Teflon sheet 5 is provided at the bottom end of the piezo element 4 in the figure. Also, the piezo element 4 is pressed against the Teflon sheet 5 by the spring 7 @Maku, and there is an O between parts 16 and 12.
A ring 13 is provided.

A key 10 is also provided between the parts 16 and 18. Further, the lid 11 is provided with a hole.

Further, the material of parts 5, 12, 17, and 18 was Teflon resin. This configuration makes it possible to do the following: ◎Installing the filter 1 in the adhesive tank 14
By providing the adhesive 9 and concentrating the adhesive 9, clogging of the orifice 2 due to dirt in the adhesive 9 can be prevented. Furthermore, since the piezo element 4 is pressed against the Teflon sheet 3 by the spring 7, dimensional errors in the length direction of the piezo element 4 are absorbed and shielding performance is improved. Also, key 10
By providing this, it is possible to prevent the component 16 from rotating when the component 12 is attached to the component 18, and to prevent the piezo element 4 from rotating and breaking. Further, by providing a hole in the lid 11, it is possible to replenish air in the same volume as the discharged adhesive 19, so that it is possible to prevent the inside of the adhesive tank 14 from becoming under negative pressure from the outside air. Also, parts 5. i2,17
．． By using Teflon resin for 18, the piezo element 4
It was possible to provide external insulation. Furthermore, when a pulse voltage is applied to the piezo element 4 in this configuration, the adhesive 9 is excited by a minute pressure as the piezo element 4 contracts minutely in the radial direction. The pressure wave generated by this is applied to the adhesive tank 1.
It is transmitted both in the direction of 4 and in the direction of orifice 2. When the pressure wave reaches the free end of the orifice 2, the adhesive liquid level rises. At this time, if a pulse voltage sufficient to generate a sufficiently high pressure wave is applied to the viscosity of the adhesive 9, the force of discharging it will outweigh the force of drawing it back inside due to surface tension.
The adhesive 9 is discharged as droplets 19 (about 100 μm in diameter).

Furthermore, if air bubbles enter the adhesive 9, pressure waves may be absorbed by the air bubbles, making it difficult to form droplets 19. In that case, by placing the tip of the device in the adhesive, making the inside of the adhesive tank 14 a lower pressure than the adhesive, and sucking the adhesive into the tank, no air bubbles will be left in the adhesive 9.
Embodiment 2 FIG. 2 schematically shows an embodiment according to claim 2 of the present invention. In (,), an orifice 2 is provided at the center of a cylindrical piezo element 4. In addition, in (b), an orifice 2 is provided at the center of a spherical piezo element 21 that is hollow inside.These piezo elements are polarized on the inner and outer walls, and when a voltage is applied, they rotate in the circumferential direction. It contracts and the pressure waves concentrate at the center.

Embodiment 6> FIG. 3 is an applied voltage waveform diagram of an embodiment according to claims 3 and 4 of the present invention. In addition, Fig. 4 is a diagram showing the state of the piezo element and adhesive at each time when the voltage of the fifth factor is applied to the piezo element. It is polarized. The piezo element 22 has a structure in which it is pasted on one wall surface 23 of the flow path. When a voltage is applied to the piezo element 22, the piezo element 22 contracts in the length direction. Therefore, a difference in length from the channel wall surface 23 occurs, and the piezo element 22 bends inside the channel and pressurizes the adhesive 9. The piezo element 22 has a voltage applied to it for a time t
, there is no distortion as shown in (a). The voltage is raised from time t to E and V at time t2. This time (t2-tl) is set shorter than the reaction time of the piezo element 22.

Therefore, at time t2, the piezo element 22 is (b)
During the displacement, the maximum strain occurs at time t25 as shown in (C). The pressure of the adhesive is due to the approximately 9 force between the pressure applied by the piezo element and the reaction force due to the inertial force and viscosity of the adhesive. rises. Then, as the adhesive gradually flows, the pressure decreases. By making the voltage rise time shorter than the reaction time of the piezo element 22 as in this embodiment, the volume in which the adhesive 9 inside the piezo element 22 flows during displacement of the piezo element 22 can be reduced. becomes possible. This makes it possible to obtain a high pressing force and to form a highly viscous adhesive into droplets.

After ejection, the droplets tend to form a sphere, a stable shape, due to the surface tension of the adhesive.

During droplet formation, adhesive flows within the droplet, creating a viscous force that opposes the surface tension.Thus, in the case of a high-viscosity adhesive, the viscous force is strong and it takes a long time to form a droplet. There is a long thread behind the droplet; and a thread that is too long will split and create multiple droplets. When a plurality of small droplets are generated in this way, the amount of coating becomes inconsistent and it is impossible to perform coating with high precision.Therefore, in this embodiment, as shown in (d), the voltage is lowered at time t5 when droplets are almost generated. ing.

At time t4, by applying a voltage E2 lower than the initial voltage, the piezo element is deformed in the opposite direction to the pressure applied as shown in (e), and the excess liquid column is sucked into the nozzle to prevent the generation of small droplets. The Deru Obokuto method is an effective means for stably obtaining a single drop when using not only adhesives but also high viscosity liquids.

<Embodiment 4> FIG. 5 is a sectional view of an embodiment according to claim 5 of the present invention. Since this embodiment is similar in structure to Embodiment 1, only the main differences will be described. In this embodiment, a pipe 25 is provided in place of the piezo element 4 of the first embodiment, and a minute heating mechanism 24 is provided in a portion of the flow path near the orifice. With this configuration, when a pulse current is passed through the minute heating mechanism 24, the adhesive 9 near the heating mechanism evaporates and minute bubbles are generated.Thus, the adhesive 9 flows between the orifice 2 and the adhesive tank 14. It is pushed away in both directions, and the adhesive liquid level rises on the orifice 2 side. At this time, if a sufficiently large pulse current is applied to the viscosity of the adhesive 9, the surface tension will outweigh the force of pulling it back inside, and the adhesive 9 will be discharged as droplets 19 (about 100 μm in diameter). be done.

<Embodiment 5> FIG. 6 is a sectional view of an embodiment according to claim 6 of the present invention. Since this embodiment is similar in structure to Embodiment 1, only the main differences will be described. In this embodiment, a conductive pipe 26 is provided in place of the piezo element 4 of the first embodiment, and an electrode 27 is provided at a position facing the orifice 2. With this configuration, when a pulsed electrostatic field is applied between the adhesive 9 and the electrode 270, the adhesive 9 is ejected as droplets 19 due to electrostatic attraction. Furthermore, according to this method, line coating is also possible by continuously applying a voltage.

<Embodiment 6> FIG. 7 is a sectional view of an embodiment according to claim 7 of the present invention. In this example, a heater 28 is provided around the entire outer periphery of the adhesive applicator of Example 1. In addition, hot melt adhesive 29
A thermocouple 30 is provided therein. With this configuration, the hot-melt adhesive 29 is thermally melted by the heater 2BK and supplied to the piezo element 4. In this state, when a pulse voltage is applied to the piezo element 4 to cause it to vibrate, the hot melted adhesive 29 is ejected in the form of droplets 19 (about 100 μm in diameter).

Embodiment 7> FIG. 8 is a sectional view of an embodiment according to claim 8 of the present invention. This shows a ring-shaped electrode below the view of the orifice 2 of the adhesive applicator according to Embodiment 1. (Charged electrode) 32,
In addition, two plate-shaped electrodes (deflection electrodes) 33 are provided at the bottom of the figure, facing each other across the path of the droplet.
With such a configuration, the following becomes possible. When the adhesive liquid level in the orifice 2 rises, for example, if a positive charge is added to the charging electrode 32, the adhesive 9
is dielectrically polarized and the liquid surface is negatively polarized. In this state, the droplet 19 separated from the liquid surface and generated is negatively charged. By passing this droplet 19 between deflection electrodes 29 to which a voltage is applied, the υ droplet 19 is deflected. This is a drop 19
The amount of deflection of the droplet 19 can be controlled by controlling the amount of charge applied by the charging electrode 28 and the voltage applied to the deflection electrode 33.C The above example is an example in which deflection is performed in one dimension. It is also possible to perform two-dimensional deflection by providing another set of deflection electrodes in a direction orthogonal to the deflection electrode 33 below the figure.

<Embodiment 8> FIG. 9 is a plan view of an embodiment of claim 9 of the present invention ◇ Also, FIG. 10 is a suction hand 39-A of the work handling robot 59 in FIG. 9. FIG. This device is for automatically pasting the jig 34 and the workpiece 37 together.

This device includes an adhesive applicator 36 provided above the heating unit 351, cooling unit 42, work supply device 38, and heating unit 55, and an adhesive applicator 36 provided above the heating unit 35 and the cooling unit 420. a work handling robot 39, two positioning robots (40-A) arranged so as to face the center of the figure from two directions, and
40-B, consists of a positioning metal fitting 41 (5-shaped metal fitting) in the center of the figure. With this configuration, the following automation became possible. The jigs 54 arranged in the heating unit 35 are carried under the adhesive coating device R36 by the work handling robot 69. The jig 64 is coated with hot-melt adhesive on its upper surface by the adhesive applicator 36 according to the present invention, and is conveyed to the center of the figure. Next, the work 57 is placed on the jig 34 by the work handling robot 39. Thereafter, positioning is performed by pressing the workpiece 57 against the side surface of the positioning metal fitting 41 from two directions using the positioning devices 40-A and 40-B. After pasting is completed, the jig 64 is carried by the work handling robot 39 to the cooling unit 42, where it is cooled and the adhesive is hardened.

〔Effect of the invention〕

According to claims 1 and 5 of the present invention, the pressure means using the piezo element and the bubble has a simple mechanism, and
Because of its small size, it is possible to install a pressure mechanism just before the oriswiss, and the amount of application is not subject to other mechanical errors. Furthermore, according to claim 6 of the present invention, since droplets are formed by electrostatic attraction, the amount of application is not affected by any mechanical difference in the droplet generation mechanism. According to items 2 to 4, it is possible to accurately apply a small amount of adhesive even with a high viscosity adhesive.

Further, according to claim 7 of the present invention, by providing a heating mechanism and making it possible to apply a hot-melt adhesive, volatile components do not evaporate because the adhesive is solid at room temperature.
In addition, since it becomes a liquid when heated, the orifice may become clogged due to hardening of the adhesive even if it is not used for a long time.
In addition, according to claims 1 to 7 of the present invention, two adhesive coating devices according to the present invention are used to apply the adhesive in the form of fine droplets. Mixed Amounts By alternately applying the adhesive one liquid at a time, the two liquids can be applied while being accurately mixed on the application surface.

According to claim 8 of the present invention, line coating on nine surfaces is possible by deflecting droplets little by little and lining up the droplets generated by the coating apparatus according to claims 1 to 7. Become. Furthermore, since the application position can be controlled with high precision, the adhesive will not stick to unnecessary positions. In addition, in the case of claim 6 of the present invention, if the time for applying the electrostatic attraction force is lengthened, it becomes possible to perform υ line coating.

According to the pasting device according to claim 9 of the present invention, not only high-precision application but also high-precision pasting can be performed automatically.

[Brief explanation of drawings]

The cross-sectional view on the flow side, FIG.
An explanatory diagram showing the state of the piezo element and adhesive over time when the voltage shown in the figure is applied, FIG. 5 is a sectional view of the embodiment of claim 5 of the present invention, and FIG. FIG. 7 is a sectional view of an embodiment of claim 6 of the invention, FIG. 8 is a sectional view of an embodiment of claim 7 of the invention, and FIG. 8 is an embodiment of claim 8 of the invention. 9 is a plan view of an embodiment of claim 9 of the present invention, and FIG. 10 is an enlarged perspective view of the suction section, jig, and workpiece of the workpiece handling robot shown in FIG. 9. It is. 2... Orifice, 4... Cylindrical piezo element, 8...
...electrode, 9...adhesive, 14...adhesive tank%
19... Adhesive drop, 21... Spherical piezo element, 2
2... Plate-shaped piezo element, 24... Electrode for minute heating mechanism, 25... Pipe embedded with minute heating mechanism, 2
6... Conductive vibrator, 27... Electrode, 28... Heater, 29... Hot melt adhesive, 52... Charging electrode, 55... Deflection electrode, 54... Jig , 35... heating unit. Figure 4 (b) (C) JP-A-3 188966 (9) Figure 7 Figure 4

Claims (1)

[Claims] 1. An adhesive tank containing an adhesive, an orifice attached to the adhesive tank, and forming a part of a flow path from the adhesive tank to the orifice. Alternatively, an adhesive application device comprising a piezo element provided to vibrate parts constituting a flow path, and a pulse wave power source connected to the piezo element. 2. In the adhesive applicator according to claim 1, the piezo element is cylindrical or hollow and spherical, and the orifice is provided at the center of the piezo element. Adhesive applicator. 3. The adhesive application device according to claim 1 or 2, wherein the pulse wave power source applies a voltage having a waveform whose rise time is shorter than the response time of the piezo element. 4. In claim 1, 2 or 3,
An adhesive application device characterized in that the pulse wave power supply applies a waveform voltage to the piezo element that lowers the voltage to a level lower than the voltage before starting up when the voltage drops. 5. An adhesive tank containing adhesive, an orifice attached to the adhesive tank, and a micro-heating mechanism connected to a pulse wave power source in a flow path from the adhesive tank to the orifice. An adhesive application device characterized by: 6. An adhesive tank containing an adhesive, an orifice attached to the adhesive tank, an electrode provided on the adhesive tank or a flow path so as to be electrically conductive with the adhesive, and the orifice. An adhesive coating device comprising electrodes provided at opposing positions and a power source that applies a high voltage between the two electrodes. 7. In claims 1 to 6, a hot-melt adhesive that is solid at room temperature and becomes liquid when heated is used, and a heater is provided on the outer periphery of the adhesive tank, inside the adhesive tank, or in the flow path. A hot-melt adhesive coating device characterized by: 8. In claims 1 to 7, the ring-shaped electrode is arranged so that the orifice is located near the center of the ring,
Further, an adhesive applicator is characterized in that it consists of two electrodes that are placed opposite each other across the path of the droplet. 9. A pasting device, characterized in that the adhesive application device according to any one of claims 1 to 8 is provided with a work supply device, a carry-out device, and a pasting position setting device. 10. A manufacturing line comprising the adhesive coating apparatus according to any one of claims 1 to 9, which includes a step of applying the adhesive. 11. A product coated with the adhesive using the adhesive coating apparatus according to claims 1 to 9.