JPS62273833A - Horn for ultrasonic plastic welder - Google Patents

Abstract

PURPOSE:To obtain inphase and uniform amplitude of oscillation at an end face in an output side of a tool horn by controlling arbitrarily the number of oscillators according to necessary electric power, by forming long and slender slits on both ends in the longitudinal direction of an arbitrary number of slots. CONSTITUTION:A plurality of slots 4 which are arranged at equal intervals in a right angle direction with an input or output direction of ultrasonic waves and are extended in the input or output direction are provided on a platelike tool horn 3a. Slits 5 which is extended, in the input or output direction in a width narrower than that of the slots 4, for both ends of the second and fourth slots 4 are formed by penetrating through a bridge part 7 on the second and fourth slots 4 which are positioned symmetrically. Stationary hours 2 to the top of which oscillators are fitted are fixed on an end face of an input side in a symmetrical position by placing on both sides of the slits 5. As oscillations transmitted to every part divided by the slits 5 of the tool horn 3a from each of the oscillators 1 are transmitted to an output side in every divided part and at least a piece of the slot 4 is provided between the slits 5, inphase and uniform amplitude of oscillation is obtained from the end face of the output side of the stationary hone 3a, even if the number of oscillations 1 is controlled to the minimum.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ultrasonic plastic welder horn used for welding plastics.

[Conventional technology]

Ultrasonic welding of plastics has many features such as no need for adhesives, fast welding speed, and a cleanly finished welded surface, and is used in a wide variety of applications, from industrial products to food packaging.

As shown in Figures 5 to 7, the ultrasonic plastic welder used for such welding includes a vibrator 1 that generates vibrations at a predetermined frequency, and a fixed horn 2 that is fixed to the vibrator 1 and transmits the vibrations. and a plate-shaped, rectangular parallelepiped-shaped, or cylindrical tool horn 3 attached to the tip of the fixed horn 2. The frequency currently used in this ultrasonic plastic welder is 15KH2 to 40KHz, with the mainstream being 20KHz.
Although it is approximately KH2, the use of higher frequencies is being considered in order to achieve the demands of improving the finish and precision of the welding surface and strong bonding with new and dissimilar materials, as well as from the perspective of reducing noise. The frequency used tends to be higher, from 60 KHz to 7Q KHz, and even higher.

However, in order to obtain uniform vibration amplitude in the same phase at the tip end face, that is, the output end face, the tool horn 3 is arranged at equal intervals of 174 or less of the excitation wavelength λ perpendicular to the input/output direction of the ultrasonic wave. A plurality of slots 4 are formed that penetrate between the sides of the horn 3 and extend in the input/output direction, but as the frequency used becomes higher, it is necessary to narrow the interval between the slots 4, and the dimensions of the tool horn 3. If they are the same, the number of slots 4 will be increased.

As the number of slots 4 increases, as shown in FIG.
The time difference between the start-up of vibration (250 microdays for four slots) becomes large between the pillar portions 6 at both ends, and this becomes a major problem in plastic welding where the operation is completed in less than 1 second. or,
The bridge portion 7 (between both ends of the slot 4 and the input/output end face of the tool horn 3) has a narrow interval of about λ/8, so as the number of slots 4 increases, the distance from directly below the vibrator 1 of the tool horn 3 to both ends It becomes difficult to supply energy to the output side, and the vibration amplitude becomes uneven on the output side end face, causing uneven welding.

Furthermore, in the case of a cylindrical tool horn 3 as shown in FIG. 7, one vibrator 1 is installed at the center of the input side end face of the tool horn 3 in order to obtain uniform vibration amplitude in the same phase at the output side end face. Moreover, the circumferential distances divided by the slots 4 on the diameter of the tool horn 3 must both be 2λ/3 or less, which limits the size of the tool horn 3.

Furthermore, as the frequency becomes higher, it becomes more difficult to manufacture a vibrator 1 with a larger diameter, so there is also the problem that the input power from one vibrator 1 becomes smaller.

In order to solve the problem caused by the increase in the number of slits, as shown in FIG.
A welder with each book attached is proposed. but,
In this case, the number of oscillators 1 increases as the number of slots 4 increases, making the device expensive and further increasing the number of oscillators 1.
Also, it is difficult to attach the fixed horn 2 to the tool horn 3, and in some cases, in order to attach the horn to a pressurizing device, it becomes impossible to form the flange 8 that has been conventionally provided on the fixed horn 2, as shown in FIG. Become.

[Problem that the invention seeks to solve]

Even if the number of slots in the tool horn increases due to the use of higher frequencies, the present invention allows the number of vibrators to be adjusted arbitrarily according to the required power, and the vibration amplitude is uniform and in phase at the output end face of the tool horn. The purpose is to provide a horn for ultrasonic plastic welding that can obtain the following.

[Means for solving problems]

The ultrasonic plastic welding horn of the present invention includes a plurality of fixed horns each having one end attached to a plurality of vibrators, and a tool horn attached to the other end of the plurality of fixed horns. a plurality of slots formed through the tool horn arranged at equal intervals perpendicular to the output direction and extending elongated in the input/output direction; and at least one slot having a symmetrical position among all the slots; It is equipped with a slit extending from both ends in the input/output direction with a width narrower than the slot and passing through the tool horn, and a plurality of fixed horns are installed symmetrically on the input side end face of the tool horn with the slits sandwiched between them. be.

〔Example〕

FIG. 1 shows a specific example of an ultrasonic plastic welder horn according to the present invention, in which a plate-shaped tool horn 3a is arranged at equal intervals in a direction perpendicular to the input/output direction of ultrasonic waves (width direction of the plate). Five slots 4, each of which is elongated in the input/output direction, extend through the tool horn 3a in the thickness direction. The distance d between the pillar portions 6 between each slot 4 is approximately λ/4 or less, and the distance d between the bridge portions 7 at both ends of the slot 4
2 is approximately λ/8. Further, in the second and fourth slots 4, slits 5 extending from both ends in the input/output direction with a narrower width than the slots 4 are formed so as to penetrate through the bridge portion 7. The length of this slit is about λ/16, so the distance between the tip of the slit 5 and the input/output side end face of the tool horn 3 @a
is preferably approximately λ/16, and the width of the slit 5 is not particularly limited as long as it is narrower than the slot 4.

Three fixed horns 2 are fixed on the input side end face of the tool horn 3a at symmetrical positions across the slit 5, and a vibrator 1 is attached to the upper end of each fixed horn 2, respectively. Seven flanges 8 are formed on the fixed horn 2 so that the entire horn can be attached to a pressurizing device (not shown).

The number and arrangement of slits are not limited to this specific example, and can be determined according to the number of required vibrators depending on the input power. For example, FIG. 2 shows another specific example in which the arrangement of the slit 5 is changed, and a plate-shaped tool horn 3bG
Five slots 4 are formed, and the central slot 4
Slits 5 are formed only at both ends in the length direction. In this case, it is sufficient to attach two fixed horns 2 symmetrically around the slit 5, and this is an example in which the number of fixed horns 2 and vibrators is the smallest.

Fig. 3 shows an annular tool horn 3C made by bending a long plate-shaped tool horn and joining both ends thereof.
Slits 5 are formed at both lengthwise ends of the slot 4 of the book. Fixed horn 2 - (The force is attached to the center of the input side end face of the tool horn 3 divided by the slit 5, that is, directly above the slot 4 that does not have the slit 5.This annular tool horn 3C
However, since the number of slits 5 can be adjusted to any number greater than or equal to 2, even if the circumferential distance divided by slots 4 is limited to 2λ/3 or less as explained earlier, the number of slots 4 and 5 A tool horn 3C with an arbitrarily large radius can be produced by increasing .

Figure 4 shows a rectangular parallelepiped tool horn 3 that is long and deep.
This is an example of d, in which five slots 4 are formed penetrating the horizontal and three longitudinal sides, and slits 5 are formed at both lengthwise ends of the central slot 4 in the vertical and horizontal directions, penetrating each side. 0 Therefore, conventionally it was necessary to install 24 fixed horns in each section divided by each slot 4, but four fixed horns 2 were installed in each section divided by slit 5. Just install it.

In addition, as shown in FIG. 1, the flange 8 formed on the fixed horn 2
If it is impossible due to size or strength to attach the tool horn to the pressure device, provide a groove on the outer surface of the tool horn and use a semicircular or U-shaped tool horn with a protrusion that fits into the groove. It is also possible to tighten and hold the tool horn using a mounting bracket having a shape corresponding to the external shape of the tool horn, and to attach it to the pressurizing device.

[Effect]

Vibrations transmitted from each vibrator 1 to each section of the tool horn 3a divided by the slit 5 via the fixed horn 2 are transmitted to the output side for each section divided by the slit 5, Since at least one slot 4 is provided between them, even if the number of vibrators 1 is minimized, in-phase and uniform vibration amplitude can be obtained from the output side end face of the fixed horn 3a. Further, even if the resonant frequencies of the vibrators used are slightly different, the combined resonant frequency including that of the tool horn 3 becomes one, resulting in a single resonance, so it can be driven by a single oscillator. The number of oscillators can be selected from the maximum number of oscillators to the minimum of one, and those with small output, medium output, and large output. However, when driving with multiple oscillators, unless each vibrator is driven with the same phase voltage (current), in-phase uniform vibration cannot be obtained on the output surface. [Effects of the Invention] According to the present invention, Even if the number of slots in a tool horn increases due to higher operating frequencies, by forming elongated slits at both lengthwise ends of any number of slots, the same number of vibrations can be generated in each section divided by the slits. Since the vibrators can be attached via the fixed horn, the number of vibrators can be arbitrarily adjusted according to the required power, and moreover, it is possible to obtain uniform vibration amplitudes in the same phase at the output side end face of the tool horn.

Therefore, it is possible to configure a vibration system with an output of nearly 200 W even at high frequencies in the 60 KHz band, improve the transparency even when welding large areas of acrylic resin, and make it possible to weld soft PVC, which has conventionally been carbonized and foamed, without powder scattering. There are unexpected effects that can expand the range of applications of ultrasonic plastic welders to many fields, such as the simultaneous multi-point caulking of PBT.

[Brief explanation of the drawing]

FIG. 1 shows a specific example of a horn for an ultrasonic plastic welder according to the present invention, in which (a) is a front view and (b) is a side view with a portion cut away along line A in (a). be. FIG. 2 is a front view of another embodiment of the present invention in which the arrangement of the slits is changed. FIG. 3 is another specific example of the present invention, which is a plan view of an annular tool horn at the input side end surface, and FIG. 4 is still another specific example of the present invention, which is a plan view of the input side end surface of a rectangular parallelepiped tool horn. FIG. 5 and 6 are front views of a horn for an ultrasonic plastic welder equipped with a conventional plate-shaped tool horn. FIG. 7 shows a horn equipped with a conventional cylindrical tool horn, and (a) is a front view thereof and (
b) is a plan view of the input side end face of the tool horn. 1. Vibrator 2. Fixed horn 3.3as 3bs 3c, aa - Tool horn 4
...Slot 5..Slit 6..Column section 7..Bridge section 8..Flange Fig. 1 (a) (b) Fig. 2 Fig. 3 b Slit

Claims (1)

[Claims] (1) Consists of a plurality of fixed horns each having one end attached to a plurality of vibrators, and a tool horn attached to the other end of the plurality of fixed horns. A plurality of slots arranged at equal intervals and elongated in the input/output direction and formed through the tool horn, and at least one slot in a symmetrical position among all the slots, which is thinner than the slots from both ends in the length direction. A horn for an ultrasonic plastic welder, comprising: a slit extending widthwise in the input/output direction and penetrating the tool horn, and a plurality of fixed horns being symmetrically attached to the input side end face of the tool horn with the slits sandwiched therebetween.