CN106827554A - A kind of ultrasonic activation mode conversion method and large scale Ultrasonic Plastic boxing system - Google Patents

Abstract

The invention discloses an ultrasonic vibration mode conversion method, which utilizes the mutual conversion principle of longitudinal vibration-bending vibration-longitudinal vibration, and comprises the following steps: Step 1, converting the ultrasonic wave in the longitudinal vibration mode into a bending vibration mode Ultrasonic wave; Step 2, fixing the metal ring welding head at the vibration amplitude position of the bending vibration mode of the disc-shaped longitudinal bending vibration transducer, so that the metal ring welding head works in the longitudinal vibration mode. The invention also discloses a large-size ultrasonic plastic ring welding system, which is used to realize ultrasonic vibration mode conversion and ultrasonic welding of large-size plastic weldments. The invention expands the application range of the traditional ultrasonic plastic welding system, reduces the production cost and improves the working efficiency of the traditional ultrasonic plastic welding system.

Description

An ultrasonic vibration mode conversion method and a large-scale ultrasonic plastic ring welding system

technical field

The invention belongs to the field of ultrasonic plastic welding, and in particular relates to an ultrasonic vibration mode conversion method and a large-scale ultrasonic plastic ring welding system.

Background technique

Ultrasonic plastic welding is a high-tech technology for welding thermoplastic products. All kinds of thermoplastic plastic parts can be welded by ultrasonic welding. When welding plastic products, no adhesives, fillers or solvents are added, and a large amount of heat is not consumed. It has the advantages of simple operation, fast welding speed, high welding strength and high production efficiency. Therefore, ultrasonic welding technology is more and more widely used.

Ultrasonic plastic welding has been widely used in the automotive, electronics, medical, home appliances, non-cloth clothing, office supplies, packaging and toy industries. Such as body plastic parts, car doors, car meters, car lights mirrors, sun visors, interior parts, filters, mobile phone accessories, chargers, toy stationery, ink cartridges, toner cartridges, washing machines, electric irons, vacuum cleaners, etc.

Traditional ultrasonic plastic welding systems are generally composed of ultrasonic transducers, ultrasonic horns, and ultrasonic welding tool heads suitable for different geometries of parts to be welded. Invention patents; another example is the Chinese invention patent with the patent number CN201220185648.7 and the patent name of the ultrasonic welding device for bearing plastic cages. The working principle of the traditional ultrasonic plastic welding system is based on the longitudinal vibration mode of the ultrasonic vibration system, that is, the high-power ultrasonic transducer generates longitudinal vibration, and after the vibration displacement is amplified by the longitudinal vibration horn, the welding tool head is pushed to generate the same frequency The ultrasonic vibration transmits the ultrasonic energy to the welding area. Due to the large acoustic resistance in the welding area, local high temperature will be generated. Due to the poor thermal conductivity of the plastic, it cannot be dissipated in time for a while, and it gathers in the welding area, causing the contact surface of the two plastics to melt rapidly. After a certain pressure is added, they are fused into one body, and the whole process of ultrasonic plastic welding is completed.

Since this type of ultrasonic vibration system is designed based on the traditional one-dimensional longitudinal vibration theory, in general, the lateral dimension of this type of ultrasonic plastic welding system should be less than a quarter of the longitudinal wavelength. Therefore, the traditional ultrasonic plastic welding system The lateral size of the PTFE is limited and cannot be used for ultrasonic welding of devices with larger geometric dimensions.

Contents of the invention

In order to solve the problem that the traditional ultrasonic plastic welding system is limited in lateral size and cannot be used for ultrasonic welding of devices with larger geometric dimensions, the present invention provides an ultrasonic vibration mode conversion method and a large-scale ultrasonic plastic ring welding system. Technical scheme of the present invention is realized like this:

A method for converting ultrasonic vibration modes, using the principle of mutual conversion of vibration modes of longitudinal vibration-bending vibration-longitudinal vibration, comprising the following steps:

Step 1, converting the ultrasonic wave in the longitudinal vibration mode into the ultrasonic wave in the bending vibration mode;

Step 2, fixing the metal ring welding head at the vibration amplitude position of the bending vibration mode of the disc-shaped longitudinal bending vibration transducer, so that the metal ring welding head works in the longitudinal vibration mode.

In the above-mentioned ultrasonic vibration mode conversion method, the first step is to convert the ultrasonic waves in the longitudinal vibration mode generated by the transducer and the ultrasonic horn into bending Ultrasound in vibration mode.

In the above ultrasonic vibration mode conversion method, the transducer, the ultrasonic horn, the disc-shaped longitudinal-bending vibration transducer and the metal ring welding head are all in a resonance state.

A large-scale ultrasonic plastic ring welding system, including a transducer that converts electrical energy into mechanical vibration, an ultrasonic horn for converging ultrasonic waves, and a metal ring welding head, the ultrasonic receiving end of the ultrasonic horn is connected to the The ultrasonic output end of the transducer is fixedly connected, and also includes a disc-shaped longitudinal-bending vibration converter for converting the longitudinal mode ultrasonic waves received from the ultrasonic horn into bending vibration mode ultrasonic waves;

The ultrasonic output end of the ultrasonic horn is fixedly connected to the disc-shaped longitudinal-bending vibration transducer, and the metal ring welding head is detachably fixed on the disc-shaped longitudinal-bending vibration transducer. A longitudinal-bending vibration transducer is placed between the ultrasonic horn and the metal ring welding head.

In particular, in order to expand the application range of the traditional ultrasonic plastic welding system, the metal ring welding head of the present invention is preferably a large-sized metal ring welding head.

As a preferred embodiment of the present invention, the thickness of the disc-shaped longitudinal-bending vibration transducer is less than one-tenth of its diameter.

As a preferred embodiment of the present invention, the size of the contact surface between the ultrasonic horn and the disc-shaped longitudinal-bending vibration transducer is smaller than one-tenth of the bending vibration wavelength of the disc-shaped longitudinal-bending vibration transducer.

As a preferred embodiment of the present invention, the metal ring welding head is located at the bending vibration displacement amplitude of the disc-shaped longitudinal-bending vibration transducer, and the radial thickness of the metal ring welding head is smaller than that of the disk-shaped longitudinal-bending vibration transducer. One-tenth of the wavelength of the bending vibration of the longitudinal-bending vibration transducer.

As a preferred embodiment of the present invention, the outer wall of the metal ring welding head is provided with a plurality of grooves, and the grooves communicate with the inner cavity of the metal ring welding head.

As a preferred embodiment of the present invention, the transducer, the ultrasonic horn and the metal ring horn are arranged perpendicular to the disc-shaped longitudinal-bending vibration transducer.

As a preferred embodiment of the present invention, the respective resonant frequencies of the transducer, the ultrasonic horn, the disc longitudinal bending vibration transducer and the metal ring welding head are the same as the vibration frequency of the ultrasonic annular plastic welding system.

Beneficial effects of the present invention:

Compared with the traditional one-dimensional longitudinal vibration system, the invention utilizes the principle of mutual conversion of vibration modes of longitudinal vibration-bending vibration-longitudinal vibration, and realizes the large-scale output of the ultrasonic plastic welding system. Therefore, the invention expands the application range of the traditional ultrasonic plastic welding system, reduces the production cost, and improves the working efficiency of the traditional ultrasonic plastic welding system.

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a schematic structural view of the present invention.

Fig. 2 is a schematic structural view of the bimetallic ring welding head of the present invention.

In the figure: 1. Transducer; 2. Ultrasonic horn; 3. Disc-shaped longitudinal bending vibration transducer; 4. Metal circular welding head; 10. Sandwich type piezoelectric ceramic ultrasonic transducer; 401. Large size Metal ring welding head Ⅰ; 402. Large-scale metal ring welding head Ⅱ.

detailed description

In order to further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific implementation, structural features and effects of the present invention will be described in detail below in conjunction with the accompanying drawings and examples.

It should be noted that the orientations or positional relationships indicated by the terms "upper", "lower", "top", "bottom", "inner" and "outer" in the present invention are based on the orientations or positions shown in the accompanying drawings The relationship is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

Example 1:

The present invention utilizes the principle of mutual conversion of vibration modes of longitudinal vibration-bending vibration-longitudinal vibration, and discloses an ultrasonic vibration mode conversion method, which includes the following steps:

Step 1, contacting the ultrasonic horn 2 in the longitudinal vibration mode with the disc-shaped longitudinal-bending vibration transducer 3, so that the disc-shaped longitudinal-bending vibration transducer 3 is in the bending vibration mode;

Step 2: Contact the disc-shaped longitudinal-bending vibration transducer 3 in the bending vibration mode with the metal ring welding head 4, so that the metal ring welding head 4 is in the longitudinal vibration mode.

In this method, the ultrasonic horn 2, the disc-shaped longitudinal bending vibration transducer 3 and the metal ring welding head 4 are all in the resonance state, and the ultrasonic horn 2, the disc-shaped longitudinal bending vibration transducer 3 in the present embodiment And the operating frequency of the metal ring welding head 4 can be specifically designed according to actual needs, as long as the ultrasonic plastic welding work can be completed.

Referring to Fig. 1, this embodiment mainly discloses a large-scale ultrasonic plastic ring welding system for realizing the ultrasonic vibration mode conversion method, which includes a transducer 1, an ultrasonic horn 2, and the ultrasonic horn 2 The other end is fixedly connected to the disc-shaped longitudinal bending vibration transducer 3 and the metal ring welding head 4, one end of the ultrasonic horn 2 is fixedly connected to the transducer 1, and the disc-shaped longitudinal bending vibration transducer 3 is located on the large-sized metal ring Above the welding head, the disc-shaped longitudinal-bending vibration transducer 3 is fixedly connected with the large-size metal ring welding head. The fixed connection in this embodiment is preferably detachable.

Wherein, the large-size metal ring welding head is located at the bending vibration displacement amplitude of the disc-shaped longitudinal-bending vibration transducer 3, preferably the large-size metal ring welding head is rigidly fixed at the bending vibration displacement amplitude of the disk-shaped longitudinal-bending vibration transducer 3 .

Among them, the transducer 1 , the ultrasonic horn 2 and the large-sized metal circular welding head in this embodiment should be strictly perpendicular to the disc-shaped longitudinal-bending vibration transducer 3 .

Among them, in order to ensure the singleness of the longitudinal vibration mode in the large-size annular ultrasonic plastic welding head and avoid the coupling between vibration modes, there are multiple grooves on the outer wall of the large-size metal ring welding head. The inner cavities of the metal ring welding heads are connected. It is preferable to process a certain number of straight grooves with a certain geometric size in the height direction of the large-size metal circular welding head.

Among them, the fixed connection between the transducer 1 and the ultrasonic horn 2 in this embodiment, the fixed connection between the ultrasonic horn 2 and the disc-shaped longitudinal bending vibration transducer 3, and the connection between the disc-shaped longitudinal bending vibration transducer 3 and the large-sized The fixed connection of the metal ring welding head can adopt any fixing method such as welding, threaded connection, riveting, and clamping in the prior art, as long as it can meet the rigid connection of the large-scale ultrasonic plastic ring welding system. Preferably, the fixed connection in this embodiment is connected by a high-strength prestressed central metal bolt, and this fixing method can make the whole system have good stability.

Wherein, the ultrasonic horn 2 is made of a metal material with high elasticity, high strength and low mechanical loss, such as titanium alloy, aluminum alloy, aluminum-magnesium alloy, stainless steel or copper. The cross-sectional shape of the ultrasonic horn 2 can be conical, exponential, catenary, stepped, and composite shapes.

Among them, the disc-shaped longitudinal-bending vibration transducer 3 is made of metal materials with high elasticity, high strength and low mechanical loss, such as titanium alloy, aluminum alloy, aluminum-magnesium alloy, stainless steel or copper. Preferably, the disc-shaped longitudinal-bending vibration transducer 3 is a disc structure with equal cross-section.

Among them, the large-size metal ring welding head is made of metal material with high elasticity, high strength and low mechanical loss. The material can be titanium alloy, aluminum alloy, aluminum-magnesium alloy, stainless steel or copper. Preferably, the metal ring welding head 4 is a ring structure with equal cross-section.

It should be pointed out that in this embodiment, in order to ensure close contact between the contact surfaces of the various components of the large-scale ultrasonic plastic girth welding system, reduce mechanical loss, and improve energy transmission efficiency, the contact surfaces of the large-scale ultrasonic plastic girth welding system should be Ensure high flatness and finish.

It should be pointed out that in order to meet the technological requirements of ultrasonic vibration mode conversion, in a large-scale ultrasonic plastic girth welding system proposed in this embodiment, the thickness of the disc-shaped longitudinal-bending vibration transducer 3 is preferably less than one-tenth of its diameter; Preferably, the size of the contact surface between the ultrasonic horn 2 and the disc-shaped longitudinal-bending vibration transducer 3 is less than one-tenth of the bending vibration wavelength of the disc-shaped longitudinal-bending vibration transducer 3; the wall thickness of the preferably large-sized metal ring welding head should be less than One-tenth of the bending vibration wavelength of the disc-shaped longitudinal-bending vibration transducer 3 . Moreover, the transducer in this embodiment is preferably a sandwich-type piezoelectric ceramic ultrasonic transducer 10, and the resonant frequency, output power and strength of the sandwich-type piezoelectric ceramic ultrasonic transducer 10 should be determined according to the actual situation of the parts to be welded .

In particular, the resonant frequencies of the transducer 1 , ultrasonic horn 2 , disc-shaped longitudinal-bending vibration transducer 3 and large-size metal circular welding head in this embodiment are consistent with the vibration frequency of the ultrasonic annular plastic welding system.

Compared with the traditional one-dimensional longitudinal vibration system, this embodiment utilizes the principle of mutual conversion of vibration modes of longitudinal vibration-bending vibration-longitudinal vibration, and realizes the large-scale output of the ultrasonic plastic welding system. Therefore, this embodiment expands the application range of the traditional ultrasonic plastic welding system, reduces the production cost, and improves the working efficiency of the traditional ultrasonic plastic welding system.

Example 2:

The difference between this embodiment and Embodiment 1 lies in the metal ring welding head 4 .

In this embodiment, by rationally designing the bending vibration mode of the disc-shaped longitudinal-bending vibration converter, the large-size ultrasonic plastic ring welding system can simultaneously drive multiple large-size ultrasonic plastic ring welding heads, thereby improving the working efficiency of the vibration system.

In order to ensure efficient and stable operation of the vibration system, each annular welding head must be located at the amplitude of the bending vibration displacement of the disc-shaped longitudinal-bending vibration transducer 3 .

Referring to Fig. 2, the annular welding head of the present embodiment includes a large-size metal ring welding head I 401 and a large-size metal ring welding head II 402, and the inner diameter of the large-size metal ring welding head I 401 is larger than that of the large-size metal ring welding head II 402 The outer diameter, and the large-size metal ring welding head I401 and the large-size metal ring welding head II402 are all located at the bending vibration displacement amplitude of the disc-shaped longitudinal-bending vibration transducer 3 .

It should be noted that the annular welding heads of the present invention are not limited to two, and according to the actual situation, the distribution of the annular welding heads can be determined by performing detailed calculations using formulas in the prior art.

In this embodiment, a plurality of metal ring welding heads are fixed on the large-scale ultrasonic plastic ring welding system, thereby improving the working efficiency of the entire ring welding system.

Example 3:

Next, with the operating frequency of 20 kHz, using the calculation formula in the prior art and accurately understanding the various parameters of the material, the sandwich-type piezoelectric ceramic ultrasonic transducer 10 and the ultrasonic horn 2 are set to half-wave ultrasonic vibration The parameters of the disk-shaped longitudinal-bending vibration transducer and the metal ring welding head are designed as follows:

1. When the material of the disc-shaped longitudinal-bending vibration transducer is aluminum alloy, and the material of the metal ring welding head is aluminum alloy:

The radius of the disc-shaped longitudinal bending vibration transducer is R=0.084 meters, and the thickness is T=0.015 meters;

The metal circular welding head has an outer diameter R1=0.084 meters, an inner diameter R2=0.0756 meters, and a height H=0.12 meters.

2. When the material of the disc-shaped longitudinal-bending vibration transducer is stainless steel, and the material of the metal ring welding head is aluminum alloy:

The radius of the disc-shaped longitudinal-bending vibration transducer is R=0.085 meters, and the thickness is T=0.0152 meters;

The metal circular welding head has an outer diameter R1=0.085 meters, an inner diameter R2=0.0765 meters, and a height H=0.12 meters.

3. When the material of the disc-shaped longitudinal-bending vibration transducer is titanium alloy, and the material of the metal ring welding head is aluminum alloy:

The radius R=0.083m and the thickness T=0.0147m of the disc-shaped longitudinal bending vibration transducer;

The metal circular welding head has an outer diameter R1=0.083 meters, an inner diameter R2=0.0747 meters, and a height H=0.12 meters.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (10)

1. A method for ultrasonic vibration mode conversion, utilizing the principle of mutual conversion of vibration modes of longitudinal vibration-bending vibration-longitudinal vibration, comprising the following steps: Step 1, converting the ultrasonic wave in the longitudinal vibration mode into the ultrasonic wave in the bending vibration mode; Step 2: Fix the metal ring welding head (4) at the vibration amplitude position of the bending vibration mode of the disc-shaped longitudinal-bending vibration transducer (3), so that the metal ring welding head (4) works in the longitudinal vibration mode. 2. The ultrasonic vibration mode conversion method according to claim 1, characterized in that: the first step is to connect the disc-shaped longitudinal-bending vibration transducer (3) to the ultrasonic horn (2) to convert energy The ultrasonic wave in the longitudinal vibration mode generated by the device (1) and the ultrasonic horn (2) is converted into the ultrasonic wave in the bending vibration mode. 3. The ultrasonic vibration mode conversion method according to claim 2, characterized in that the transducer (1), the ultrasonic horn (2), the disc-shaped longitudinal bending vibration transducer (3 ) and the metal ring welding head (4) are in a state of resonance. 4. A large-scale ultrasonic plastic ring welding system, including a transducer (1) that converts electrical energy into mechanical vibration, an ultrasonic horn (2) for converging ultrasonic waves, and a metal ring welding head (4). The ultrasonic input end of the ultrasonic horn (2) is fixedly connected to the ultrasonic output end of the transducer (1), and it is characterized in that it also includes a longitudinal direction for receiving from the ultrasonic horn (2). A disc-shaped longitudinal-bending vibration transducer (3) for converting modal ultrasonic waves into bending vibration modal ultrasonic waves; The ultrasonic output end of the ultrasonic horn (2) is fixedly connected to the disc-shaped longitudinal-bending vibration transducer (3), and the metal ring welding head (4) is detachably fixed on the disc-shaped longitudinal-bending vibration transducer (3). On the bending vibration transducer (3), the disc-shaped longitudinal bending vibration transducer (3) is placed between the ultrasonic horn (2) and the metal ring welding head (4). 5. The large-size ultrasonic plastic girth welding system according to claim 4, characterized in that the thickness of the disc-shaped longitudinal-bending vibration transducer (3) is less than one-tenth of its diameter. 6. The large-size ultrasonic plastic ring welding system according to claim 4, characterized in that the size of the contact surface between the ultrasonic horn (2) and the disc-shaped longitudinal bending vibration transducer (3) is smaller than the size of the One-tenth of the bending vibration wavelength of the disc-shaped longitudinal-bending vibration transducer (3). 7. The large-size ultrasonic plastic ring welding system according to any one of claims 4-6, characterized in that the metal ring welding head (4) is located at the end of the disc-shaped longitudinal bending vibration transducer (3) and the radial thickness of the metal ring welding head (4) is less than one-tenth of the bending vibration wavelength of the disc-shaped longitudinal-bending vibration transducer (3). 8. The large-size ultrasonic plastic ring welding system according to any one of claims 4-6, characterized in that, the outer wall of the metal circular welding head (4) is provided with a plurality of grooves, and the grooves It communicates with the inner cavity of the metal ring welding head (4). 9. The large-size ultrasonic plastic ring welding system according to any one of claims 4-6, characterized in that the transducer (1), ultrasonic horn (2) and metal ring welding head (4 ) is set perpendicular to the disc-shaped longitudinal-bending vibration transducer (3). 10. The large-scale ultrasonic plastic ring welding system according to any one of claims 4-6, characterized in that the transducer (1), ultrasonic horn (2), and disc-shaped longitudinal bending vibration transducer The respective resonant frequencies of (3) and the metal ring welding head (4) are the same as the vibration frequency of the ultrasonic ring plastic welding system.