JPH11268135A - Ultrasonic joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain strong bond strength, to prevent the damage of a product and the bulging out of molten resin, and to reduce the output of ultrasonic waves. SOLUTION: In an ultrasonic joining method in which a socket-shaped material 2 of a synthetic resin and a spigot-shaped material 1 are mounted on a jig, the vibration of a ultrasonic vibrator is transmitted to the materials 1, 2 through a tool horn P, and the joining surfaces la, 2a of the materials 1, 2 are welded, energy directors 11, 12 are formed at least two places on the joining surface 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic joining method in which ultrasonic vibrations are applied to superimposed synthetic resin materials and the joining surfaces are welded to each other. And an ultrasonic bonding method for stabilization.

[0002]

2. Description of the Related Art An ultrasonic bonding method is known as one of the methods for bonding synthetic resins. The ultrasonic bonding method applies ultrasonic vibration to a pair of superimposed or abutted workpieces and melts the bonding surfaces by frictional heat generated when the contact surfaces of the workpieces slide and contact with each other. This is a method in which the molten portion is solidified and joined when cooled after stopping the application of the pressure.

[0003] The conventional ultrasonic bonding method for synthetic resin materials is, for example, as shown in a sectional view of FIG. 7, a single energy director 71 is provided on a bonding surface 7a of a workpiece 7 to which ultrasonic waves are applied. And while applying ultrasonic waves from the back surface 70 of the workpiece 7 through the tool horn P, the other workpiece 8
To the joint surface 7a and the joint surface 8a of the article 8 to be joined.
And was to be welded.

In the above-mentioned conventional method, since only one energy director is provided, as shown in FIG. 8, the joining surface 7a of the article 7 and the joining surface 8a of the article 8 are melted. R ₃ is pushed by the end face 81 of the article 8,
The resin 7 is pushed upward between the inner surface 72 of the article 7 and a state called “resin protrusion” which deteriorates the appearance of the product.

[0005] Further, there is a problem that the ultrasonic wave transmitted from the tool horn P causes a flaw on the back surface 70 of the article 7 to be in contact with the ultrasonic wave.

As a method for improving the bonding strength, there is an ultrasonic plastic welding apparatus described in Japanese Patent Application Laid-Open No. 57-80019. This is achieved by reducing the length from the upper end of the tool horn to the welding surface of the workpiece and the length from the lower end of the jig to the welding surface so that the welding surface matches the nodes of ultrasonic vibration. Complete welding is possible with output. However, depending on the shape and hardness of the workpieces, setting by the technique described in the above publication may be very difficult, and it is difficult to cope with various workpieces.

Japanese Patent Application Laid-Open No. Sho 62-55120 discloses that a short fiber is placed on the surface of one synthetic resin material, and ultrasonic vibration is applied to the other synthetic resin material superimposed on the short fiber to join the short fibers. Are described. According to this method, it is possible to firmly join the two synthetic resin materials without reducing the strength.

According to the method described in JP-A-62-55120, a short fiber and an operation of arranging the short fiber are required in addition to the article to be joined, which increases the cost. Depending on the joining conditions, the contact surface between the tool horn and the article to be joined may be decomposed or deteriorated, or the synthetic resin may be excessively melted, causing poor fusion such as protruding to the outer peripheral portion. Further, there is a problem that the device becomes complicated and it may be difficult to use the device depending on the shape of the object.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides an ultrasonic bonding method that can obtain a strong bonding force, does not cause damage to an object to be bonded, and does not protrude a molten resin. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided an ultrasonic bonding method comprising: mounting a receiving object and a receiving object made of synthetic resin on a jig; Then, the vibration of the ultrasonic vibrator is transmitted to the workpiece through the tool horn, and the ultrasonic director vibrates the bonding surface of the workpiece.
Or more.

According to a second aspect of the present invention, there is provided an ultrasonic bonding method comprising the steps of: placing a receiving port-like workpiece and an insertion port-forming workpiece made of synthetic resin on a jig; In the ultrasonic bonding method of transmitting the vibration of the object to the object to be bonded through the tool horn and welding the surface of the object to be bonded by the ultrasonic vibration, a resin pool portion is provided at the tip of the socket-shaped bonding surface. It is characterized by.

Further, according to a third aspect of the present invention, there is provided an ultrasonic bonding method comprising: mounting a receiving object to be welded and a receiving object to be inserted made of synthetic resin on a jig; In the ultrasonic bonding method in which the vibration of the vibrator is transmitted to the workpiece through the tool horn, and the ultrasonic vibration is used to weld the bonding surface of the workpiece, a resin pool is formed at the back of the insertion-shaped bonding surface. It is characterized by being provided.

The synthetic resin material used in the present invention is not particularly limited as long as it is a thermoplastic resin, and examples thereof include polypropylene, polyethylene, polycarbonate, polyamide, ABS, and polyvinyl chloride.

(Function) According to the ultrasonic bonding method of the first aspect, the number of energy directors on the bonding surface is set to two or more, so that the melting start point of the resin increases with the number of ultrasonic energy action points. More. Thereby, the joining can be started after the objects to be joined are arranged at positions closer to each other, so that the output of the ultrasonic wave can be reduced. Further, the innermost energy director portion can prevent the molten resin from protruding from the energy director at a shallower portion.

According to the ultrasonic bonding method of the present invention, since the resin pool is provided at the end of the joint surface of the receiving object, the molten resin is prevented from protruding to the outer peripheral portion. You.

According to the ultrasonic bonding method of the third aspect, since the resin pool is provided in the deep portion of the joining surface of the insertion-shaped article, the molten resin is prevented from protruding to the outer peripheral portion. You.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 shows an embodiment of the present invention, in which an insertion-shaped article 1 which is a molded article made of hard polyvinyl chloride and a receptacle-shaped article 2 which is made of the same material. FIG. 3 is a cross-sectional view of a main part showing a positional relationship before bonding. The joining surface 1a of the insertion target 1 has a stepped shape in which energy directors 11 and 12 are provided at two places, and the joining surface 2a of the receiving target 2 has a mouth shape.
Has been faced with. An ultrasonic oscillator (USWP-2410, manufactured by Ultrasonic Industry Co., Ltd.) is provided on the back surface 10 of the workpiece 1 via a tool horn P.
(Z21S, not shown)
As shown in FIG. The vicinity of the energy directors 11 and 12 of the article 1 to be joined and the joining surface 2a of the article 2 to be brought into contact therewith were melt-bonded. R ₁ is melt adhered portion.

As a result of performing the joining operation 20 times under the same conditions as above, the average joining strength was 15000N, and the standard deviation was 120.
No damage was found on the contact surface with the tool horn P, that is, on the back surface 10 of the article 1 to be welded, and there was no protrusion of the resin.

(Embodiment 2) FIG. 3 is a cross-sectional view of a main part of another embodiment of the present invention. The resin pool 41 is provided at the tip of the joint 4. While applying ultrasonic vibration from the back surface 30 of the article 3 in the same manner as in Example 1, the article 3 was pressed toward the other article 4. As shown in FIG. 4, the joining surface 3 a of the article 3 to be joined following the energy director 31 and the joining surface 4 a of the article 4 to be joined are melted, and the molten resin R ₂ is stored in the resin pool 4.
1 and both were joined without protruding outside. In addition, the workpiece 3 in the form of an opening that comes into contact with the tool horn P
There was no scratch on the back surface 30 and no resin protruded.

(Embodiment 3) FIG. 5 is a cross-sectional view of a principal part showing still another embodiment of the present invention. In this embodiment, one energy director 51 is provided on an insertion-shaped article 5 to be joined. A resin pool 53 is provided by a protruding portion 52 at the back of the object 5. Example 1 from the back surface 50 of the article 5
In the same manner as described above, while receiving ultrasonic vibration,
Side. The joining surface 5a of the article 5 following the energy director 51 and the joining face 6 of the article 6 in contact with the energy director 51
a was melted, the molten resin R ₂ was filled in the resin reservoir 53, and the two were joined without protruding outside. In this case as well, there were no scratches on the back surface 50 of the article 5 to be brought into contact with the tool horn P and no resin protrusion.

(Comparative Example 1) As shown in FIG. 7, an object to be joined was provided in the same manner as in Example 2 except that an energy director 71 was provided at one position of the object 7 and no resin reservoir was provided. 7 and the article 8 were joined. The average joining strength was 9600 N and the standard deviation was 350. The back surface 70 of the article 7 in contact with the tool horn was damaged, and many resin protrusions were found on the outer periphery of the joint.

[0022]

According to the ultrasonic bonding method of the present invention, a bonded article having excellent bonding strength can be obtained, resin is prevented from protruding from a bonded portion, and the quality of a product is improved, and a stable quality is obtained. A joint is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing an embodiment of the present invention and showing a state before joining.

FIG. 2 is an essential part cross-sectional view showing a state after bonding in the embodiment shown in FIG. 1;

FIG. 3 is a cross-sectional view of a main part showing a state before joining according to another embodiment of the present invention.

FIG. 4 is an essential part cross-sectional view showing a state after bonding in the embodiment shown in FIG. 3;

FIG. 5 is a cross-sectional view of a main part showing a state before joining according to yet another embodiment of the present invention.

FIG. 6 is a sectional view of a main part showing a state after bonding in the embodiment shown in FIG. 5;

FIG. 7 is an essential part cross-sectional view showing an example of a conventional ultrasonic bonding method and showing a state before bonding.

8 is a cross-sectional view of a main part showing a state after joining by the conventional method shown in FIG. 7;

[Explanation of symbols]

1, 2, 3, 4, 5, 6, 7, 8: Workpiece 10, 20, 30, 50, 70: Back 11, 12, 31, 51, 71: Energy director 41, 53: Resin pool 52 : Projecting parts 1a, 2a, 3a, 4a, 5a, 6a, 7a, 8a: Bonding surface R ₁ : Fused adhesive part R ₂ , R ₃ : Molten resin P: Tool horn

Claims (3)

[Claims] An object to be joined having a mouth-like shape and an object to be joined having a mouth shape are placed on a jig and a vibration of an ultrasonic vibrator is applied to the object to be joined via a tool horn. In an ultrasonic joining method for welding a joint surface of an object to be joined by the ultrasonic vibration, an ultrasonic director has two or more energy directors on the joint surface. 2. A receiving object to be joined and an inserting object to be inserted made of a synthetic resin are placed on a jig and a vibration of an ultrasonic vibrator is applied to the object to be joined via a tool horn. An ultrasonic bonding method for transmitting a joint surface of an object to be welded by the ultrasonic vibration, wherein a resin reservoir is provided at a tip end of a socket-like joint surface. 3. A receiving object to be joined and an inserting object to be joined, which are made of synthetic resin, are placed on a jig and a vibration of an ultrasonic vibrator is applied to said object through a tool horn. In an ultrasonic joining method for welding a joint surface of an object to be joined by the ultrasonic vibration, an ultrasonic joining method is provided in which a resin reservoir is provided in a deep portion of an insertion-shaped joint surface.