JPH01133718A - Ultrasonic welding device - Google Patents

Abstract

PURPOSE:To make various plastic films or sheets weldable easily, by a method wherein two horns where they are fitted to two vibrators arranged on the same plane at an angle of 90 deg. and their processing surfaces running parallel with each other by facing on each other are provided and the processing surfaces are touched or separated from each other relatively. CONSTITUTION:Two vibrators 3 and horns 1 which are united with an ultrasonic vibrator 4 are arranged on the same plane at an angle of 90 deg.. The other ends of the two horns 1 form isoceles crest forms formed of the surface meeting at right angles with the plane forming an angle of 45 deg. to a direction of a vibration. Then processing surfaces 2 of the two horns 1 are faced on each other by running parallel with each other. The two vibrators 3 are supported at an end of a supporting arm 5 of the same length as the vibrator 3 at a horn 1 side and the other end of the supporting arm 5 is movable centering around a pin 6 fitted to a supporting rest 7 as a fulcrum. An air cylinder 8, for example, runs parallel with the processing surface 2 and fixed to the supporting rest 7 by protruding its rod in the opposite direction. The rod and a connecting rod 9 is connected with each other by a pin 10, which is made rockable. With this construction, a temperature of a welding surface can be raised and welding of various films can be performed appropriately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an ultrasonic welding device mainly used for welding and closing one end of a tube or the like formed of a plastic film.

[Conventional technology]

BACKGROUND ART For containers for toothpaste, mustard paste, etc., tube-shaped tubes made of flexible plastic composite film are mainly used. This tube is filled with contents from the end opposite to the mouth, and then the end is sealed. As this sealing method, heat sealing, hot air sealing, high frequency induction heating sealing, ultrasonic heating sealing, etc. are often used. Among these, ultrasonic heat sealing has a great advantage over other methods in that even if the contents adhere to the sealing portion, sealing defects will not occur.

There are three methods for this ultrasonic seal. One of them is, as shown in Fig. 5, a machined surface (radiation surface) 2 perpendicular to the vibration direction is attached to the other end of the horn 1, one end of which is connected to the vibrator 3, so that longitudinal vibration is imparted by the vibrator 3. A method of applying vibration from a direction perpendicular to the welding surface (longitudinal vibration method) by sandwiching a plastic tube 12 between it and a support 11 placed opposite the processing surface 2, as shown in FIG. As shown in Fig. 7, a machined surface 2 is formed at the other end of the horn 1 parallel to the vibration direction of the longitudinal vibration applied to the horn 1, and vibration is applied parallel to the welding surface (transverse vibration method). The horn 1 and the vibrator 3 are arranged at an angle of 45° to the receiving surface of the receiver 11, and the machined surface 2 is placed at the other end of the horn 1 at an angle of 45° to the vibration direction so as to be parallel to the receiving surface. There is a method of applying vibration in an oblique direction to the welding surface (oblique vibration method).

The longitudinal vibration method shown in FIG. 5 is the most commonly used method for welding plastic films, but is rarely used for composite films made by laminating aluminum foil because the aluminum foil is destroyed. On the other hand, the transverse vibration method shown in FIG. 6 is often used for welding aluminum laminate tubes because it causes less damage to the aluminum foil.

However, since the vibration is applied parallel to the film surface, the energy is not well transmitted in the thickness direction of the film, so when welding thick films, the welding time becomes long and productivity becomes extremely poor. The oblique vibration method shown in Fig. 7 has characteristics intermediate between the longitudinal vibration method and the transverse vibration method, but it also has drawbacks, and cannot be said to be a definitively advantageous method.On the other hand, the tube vibration method Various materials are being used for tubes as the contents enclosed within them become more diverse, and tubes, like other products, are becoming more diverse and produced in small quantities. Nowadays, a method for welding tubes after filling them with contents that can be used with a variety of tube materials has become necessary.

[Problem that the invention seeks to solve]

The present invention solves the problems in the conventional methods described above,
It is an object of the present invention to provide an ultrasonic welding device that can weld more efficiently than conventional methods and can easily and appropriately weld various films of different materials and thicknesses.

[Means for solving problems]

The means for solving the problems according to the present invention includes two vibrators arranged at an angle of 90° on the same plane, and two vibrators attached to each vibrator so that the machined surfaces face each other and are parallel to each other. An ultrasonic welding device comprising two horns and a driving device coupled to ten thousand or both of two vibrators that move the processed surfaces of the two horns toward and away from each other, and The ultrasonic welding apparatus includes an ultrasonic oscillator coupled to the two vibrators and capable of making the phases of the vibrations of the two vibrators the same or different.

[Effect]

Generally, in ultrasonic welding, it is ideal that the part to be welded has the highest temperature, while the temperature of other parts is kept as low as possible. For example, in the well-known ultrasonic transmission welding of plastic molded products, as shown in FIG. The density of the ultrasonic energy transmitted to the plastic molded product 13 on the engineering side is
By increasing the height at the protrusion 14 to the maximum level, only the welded portion generates heat, and other parts do not generate heat, allowing welding without damaging the appearance.

However, in the case of plastic films and sheets, it is not possible to provide protrusions to concentrate energy at the welded part, and at the same time, the material itself is flexible and the transmission of ultrasonic waves is very poor, so the contact between the two sheets that is the welded part is difficult. It is not possible to selectively heat just the surface.

The results of examining the humidity distribution in the thickness direction of the tube 12 when using the longitudinal vibration method shown in FIG. 5 are as shown in temperature curve A in FIG. 9, and when using the transverse vibration method shown in FIG. The temperature distribution in the thickness direction of the tube 12 became as shown by temperature curve B in FIG. In both FIGS. 9 and 10, the temperature drops rapidly on the contact surface between the processed surface 2 of the horn 1 and the film, but this is because the temperature of the horn 1 is close to room temperature.
This is thought to be because the heat generated within the film due to ultrasonic vibration is absorbed by the horn 1. If there is no heat dissipation to the horn 1, the temperature of the part of the film that is in contact with the horn 1 will be the highest, and then the ultrasonic energy in the film will gradually decrease toward the receiver 11, so the temperature will increase. The decrease in the value should also form a gradient following this.

In fact, the measured temperature curves A and B in FIGS. 9 and 10 are curves that meet the above reasons. In FIG. 10, the highest temperature portion is closer to the horn 1 side than in the case of FIG. 9. This is because the transmission of ultrasonic waves is poorer in the transverse vibration method than in the longitudinal vibration method, and energy consumption near the horn is greater. The temperature curve obtained by the oblique vibration method shown in FIG. 7 is an intermediate curve between FIG. 9 and FIG. 10.

From this, in the case of the conventional method shown in Figures 5, 6, and 7, the highest temperature part is not located on the contact surface (welding surface) between the films, but on the horn 1 side. It can be seen that it is located within the film. Therefore, if you try to raise the temperature of the welding surface to a temperature that allows welding, the temperature of the film on the horn 1 side will become higher than necessary, causing excessive deformation, which not only spoils the appearance but also creates pinholes near the welding area. Cracks had formed, causing seal failure. On the other hand, if the supplied energy is reduced in order to improve the appearance of the horn side and eliminate the occurrence of pinholes near the welded part, the temperature of the welded part will rise sufficiently, resulting in defective welding. In order to perform sufficient welding without appearance defects or pinholes, it is necessary to control conditions such as load, welding time, energy amount, etc. during the welding process within a very narrow range.
In practice, this control is extremely difficult, and problems such as poor sealing and poor appearance often occur.

The present invention focuses on the above temperature curves, and by placing horns on both sides of the sheet and applying ultrasonic vibrations from both sides, the respective temperature curves A1B shown in FIGS. 9 and 10 are superimposed symmetrically. Therefore, the curve that is the sum of the two forms a symmetrical mountain shape that is flat in the center and low on both sides.

Therefore, the temperature at the welding surface can be maximized. However, even if this method is applied to the longitudinal vibration method shown in FIG. 5, the problem of destruction of the aluminum laminate film cannot be solved. Furthermore, applying the transverse vibration method shown in FIG. 6 is extremely inefficient. Therefore, by applying this method to the oblique vibration method shown in FIG. 7, various films can be properly and efficiently welded.

That is, as shown in FIG. 4, if the horns 1 are arranged at an angle of 90 degrees to each other on the same plane, and the machined surfaces 2 of both horns 1 are formed so as to face and be parallel to each other, the tube is cut by the horn 1 on the right side. A temperature curve Ca is generated in the thickness direction within the horn 12, and a temperature curve cb is generated depending on the horn 1 on the left side.
As a result, a temperature distribution as shown by the temperature curve is actually generated in the thickness direction of the tube 12, making it possible to raise the temperature of the welding surface to the highest and to properly weld various films.

Ultrasonic welding of plastic films or sheets requires the two films or sheets to be subjected to vibrations in opposite directions. In a conventional ultrasonic welding device, the receiver side is considered to be fixed, so it is relatively subjected to vibrations in the opposite direction. In the case of the device of the present invention, when vibrations of the same frequency and the same amplitude are applied to the two horns 1 in the same phase, the vectors of the vibrations of the two horns are 90 degrees from each other as shown in FIG.
The line is a dotted line that forms an angle of 0° and has arrows pointing in the same direction. This vector can be divided into a vector component in a direction along the machined surface and a vector component in a direction perpendicular to this. Vector components in the direction along the machined surface are in phase, and vector components in the direction perpendicular to the machined surface are out of phase.

Vector components that are in phase do not contribute to welding, but vector components that are in opposite phases to each other contribute to welding, so welding is performed in the same manner as in the device shown in FIG. This is based on the same principle as in Figure 5. In the case of such an effect, it is not suitable for welding an aluminum laminate film as described above.

When vibrations of the same frequency and the same amplitude are applied to two horns 1 in opposite phases, the vibration vector of the two horns is the third
As shown in the figure, the straight lines are indicated by dotted lines that make an angle of 90° to each other and have arrows pointing in opposite directions. In this case, the vector components in the direction along the machined surface have opposite phases, and the vector components in the direction perpendicular to the machined surface have the same phase. This means that welding is performed in the same manner as the apparatus shown in FIG.

That is, according to the present invention, by using an ultrasonic oscillator that is coupled to two vibrators and can make the phases of the vibrations of the two vibrators the same or different, the phases of the vibrations applied to the two horns can be made to be in phase. By setting the phase to the opposite phase, or using a phase in between, it becomes possible to perform welding that is suitable for the material of the film to be welded, and together with the effects of the above configuration, it becomes easier and easier to weld the film. Be able to do it properly.

Furthermore, by making it possible to replace the two horns with ones that have different vibration magnifications and making the amplitudes of the two horns different from each other, it is possible to handle films with different thicknesses or materials made of different materials. When welding the film, it becomes easier to set conditions for appropriately performing the welding.

[Embodiment] FIG. 1 shows an embodiment of the apparatus of the present invention. 2
The transducers 3 are coupled to an ultrasonic oscillator 4, and each has a built-in transducer that converts electrical vibrations supplied from the ultrasonic oscillator 4 into mechanical vibrations. One end of the horn 1 is connected to the mechanically vibrating portion of the vibrator 3 by screwing, so that the mechanical longitudinal vibration generated in the vibrator 3 is transmitted to the horn 1. . The two vibrators 3 and the horns 1 are arranged on the same plane at an angle of 90°, and the other ends of the two horns 1 are arranged at right angles to the plane forming an angle of 45° with respect to the vibration direction. The two horns 1 have an isosceles chevron shape, and the machined surfaces 2 of the two horns 1 face each other and are parallel to each other. The two vibrators 3 are supported by one end of a support arm 5 of the same length on the horn 1 side, and the other end of the support arm 5 is movable by a pin 6 attached to a support base 7 using the pin 6 as a fulcrum. It has become. An air cylinder 8 is fixed to the support base 7 in parallel with the processing surface 2, with its rod protruding from the opposite side of the processing surface 2. Connecting rod 9 connects this rod to the horn 1 mounting side and the opposite side of the vibrator, and pin 1 is connected to each other.
It is connected so that it can swing at 0.

The ultrasonic oscillator 4 is capable of making the electrical vibrations supplied to the two vibrators 3 different in phase or in phase.

The embodiment shown in FIG. 1 is an example in which a link mechanism is used to bring two vibrators 3 closer together or apart using one air cylinder 8, but two vibrators 3 are moved by separate air cylinders. The two machining surfaces 2 may be configured to approach or separate from each other, or the vibrator 3 on one side may be fixed and only the vibrator 3 on the other side may be moved using a lever or the like.

Furthermore, it goes without saying that the device of the present invention can be used not only for welding plastic tubes but also for general sheets and films.

〔Effect of the invention〕

According to the apparatus of the present invention, various plastic films and sheets can be appropriately and easily welded.

[Brief explanation of the drawing]

Figure 1 is a front view of one embodiment of the apparatus of the present invention, Figure 2 is a vector diagram of vibrations on the machined surface when vibrations in the same phase are applied to the two horns of the apparatus of the present invention, and Figure 3 is the apparatus of the present invention. Figure 4 is a vector diagram of vibrations on the machined surface when vibrations of opposite phase are applied to the two horns, Figure 4 is a temperature distribution curve in the thickness direction of the welded film when welding is performed by the apparatus of the present invention, Figure 5 , Figures 6 and 7 are diagrams showing three conventional devices, Figure 8 is a diagram showing an example of welding plastic molded products, and Figure 9 is a diagram showing an example of welding a plastic film using the equipment shown in Figure 5. FIG. 10 is a diagram showing the temperature distribution curve in the thickness direction of the film when the plastic film is welded by the apparatus shown in FIG. 1. Horn 2. Machining surface 3. Vibrator 4. Ultrasonic oscillator 5. Support arm 6. Support pin 7. Support stand 8. Air cylinder 9. Connecting rod 10. Bin Applicant Seidensha Electronics Co., Ltd. Figure 1 Figure 2 Figure 3 Horn 1 Hoe blade Horn 1y'fX
-1 Figure 4 Figure 5

Claims (4)

[Claims] (1) Two vibrators arranged on the same plane at an angle of 90°, two horns attached to each vibrator and formed so that the machined surfaces face each other and are parallel to each other, and these two An ultrasonic welding device comprising: a driving device coupled to one or both of two vibrators that move the processed surfaces of the horn toward and away from each other. (2) The ultrasonic welding apparatus according to claim (1), wherein the two horns are replaceable with horns having different vibration magnifications. (3) Two vibrators arranged on the same plane at an angle of 90 degrees, two horns attached to each vibrator and formed so that the machined surfaces face each other and are parallel, and these two A drive device coupled to one or both of the two vibrators that moves the machining surface of the horn relatively toward and away from each other, and a phase of electric vibration coupled to the two vibrators and supplied to the two vibrators. An ultrasonic welding device equipped with an ultrasonic oscillator that can make the parts the same or different. (4) The ultrasonic welding apparatus according to claim (3), wherein the two horns are replaceable with horns having different vibration magnifications.