CS197995B1 - Ultrasonic instrument with superficial finish - Google Patents

Description

The present invention relates to the surface treatment of ultrasonic tools, for example for welding or forming various materials, bonding textiles, in particular nonwovens, introducing ultrasound into metal melts and aggressive environments.

In ultrasonic and e-ultrasonic treatment, materials are fed from the electromechanical transducer to the material to be processed by means of transducers, amplitude transformers and various horns. The last member of the electroacoustic system that comes into direct contact with the material being processed is called an ultrasonic tool. It can be designed as a simple waveguide or as a transformer of oscillation amplitude and variable cross-section. This ultrasonic tool, with its working end, the so-called tool face, touches the material to be processed and delivers ultrasonic oscillating energy to it.

Ultrasonic treatment of materials is necessary to understand:

1. All processes utilizing the thermal effects of ultrasound on materials such as welding and riveting of thermoplastic materials or materials containing thermoplastics, in particular non-woven fabrics, as well as the insertion of metal components into thermoplastic materials.

2. All thermal and thermal-thermal processes taking place using ultrasound, such as the action of ultrasound on the melt.

3. Ultrasonic forming and machining of materials, such as wire drawing and machining of hard materials.

197 995

197 995

4. Ultrasonic welding of metals, soldering and plating.

Ultrasonic tools are mainly made of duralumin, titanium and its alloys, possibly also from steel. Steel tools age show a poorer acoustic properties.

Selo instruments coming into contact with the material being processed wear out rapidly during the working process, whether by abrasion or other deterioration of the surface of the instrument material as a result of the physico-chemical processes occurring in non-contact between the instrument material and the material being processed.

The wear of the Sela tool can be reduced or slowed in various known ways. In particular, thermal and chemical treatments are used to increase the resistance of Sela tools, such as cementation. However, the increase in tool resistance by cementation is small compared to the cost of the treatment.

It is also known to provide a tool end with a replaceable end which is made of hard material and screwed onto the end of the tool. Finally, it is known to increase the service life of ultrasonic tools by soldering, welding, or gluing hard material inserts to the face of the tool. Both of these known methods are disadvantageous because they alter the acoustic parameters of the oscillation system, which must be considered in the design and manufacture of ultrasonic instruments, in each case separately.

In ultrasonic treatment processes where ee utilizes the thermal effects of ultrasound, it dissipates heat from the processed material to the ultrasonic tool, thereby reducing the energy efficiency of the process, and in some cases heat dissipation is intense, making it impossible to use ultrasonic treatment theohnology. The heat transferred to the ultrasonic tool increases the temperature of the tool and changes the processing conditions. This is often the case, for example, in the welding of thin thermoplastic materials, by the particular constriction of the ultrasonic tool, which is to ensure the cooling of the tool and thus even welding of the material.

When using ultrasound in chemical-thermal prooeseoh, heat transfer not only to the ultrasonic tool but also to the electromechanical transducer, thereby changing the acoustic parameters of the system and often distorting the surface of the ultrasonic tool materials, such as or when introducing ultrasound into aggressive environments.

It is known in the art to reduce the heat loss resulting from the removal of heat into the ultrasonic tool by inserting thermal insulating interlayers, e.g., Teflon film, paper, glass fiber fabric, and the like, between the ultrasonic tool and the material being processed. This method can only be used in the processing of sheet materials, eg in foil welding, but with several disadvantages which further limit its use. This is because the interlayer is easy to wear, adheres to some materials, makes visual control of the processing difficult and makes handling of the material more difficult.

The situation is even more complicated when ultrasound is applied to the melt. Here, titanium ultrasonic instruments are used, the length of which is several times the wavelength, or that various methods of cooling the instruments with gases or liquids are used. No special alloy tools are used to protect your instruments from disturbing their surfaces by aggressive environments.

However, none of the known methods can prevent physicochemical processes, for example at the interface between the surface of the ultrasonic tool and the melt, and the resulting disruption of the surface of the tool material while contaminating the melt. _t

The disadvantages described above, which occur in the processing of materials by ultrasound, namely rapid wear of the ultrasonic tool face by physicochemical processes, the influence of aggressive environment and heat dissipation into the tool, aims to eliminate the ultrasonic tool intended for welding or forming various materials, bonding The invention is based on the fact that at least on the working part of these tools at least one layer of metal, ceramic, metal-ceramic or synthetic coating material is applied by thermally plasma spraying. . Particularly preferred refining materials are, for example, alumina, titanium dioxide, a mixture of both, tungsten, tungsten carbide, a mixture of tungsten carbide with cobalt, calcium metazirconate.

Accordingly, by the method of the present invention using thermal plasma spraying, a variety of coating materials can be applied to the base material, and the properties of the deposition consisting of at least one layer can be varied according to the application conditions and the quality of the starting material. Thus, on almost any substrate, sufficiently adhering surface layers of the desired thickness and properties can be achieved. The invention takes advantage of all the advantages of inexpensive plasma thermal spraying technology. This technology is advantageous because the thin layer of deposited refining material does not affect the oscillating properties of the ultrasonic tool, so that no changes in the design or manufacture of the tools are necessary, as is the case with known ultrasonic tools. With the method according to the invention, it is sufficient to adapt only the working parts of the tools.

Metal oxides, such as alumina and titanium dioxide, which can be applied by thermal plasma spraying, are highly abrasion-resistant and have a low thermal conductivity coefficient.

The advantages of the invention will be better understood from the description of examples of its implementation.

At the working ends of the ultrasonic tools used for ultrasonic welding of nonwoven fabrics, an AlgO4 + 3% TiOg layer of 0.3 mm thickness was applied by thermal plasma spraying.

It should be noted here that prior to the spraying, the ends of the ultrasonic tools were degreased and blasted with a No. 36 steel grit. 80% Cr, 20% Ni with a layer thickness of 0.05 mm was used as the binding metal. The mean particle size of the AlgOg + 3% TiŮg powder used was 20 µm. The carrier gas was argon. The following have been modified:

Tool No. 1, which was a titanium tool of exponential shape with a circular cross-section with a working cone diameter of 11 mm.

Tool No. 2, which was a duralumin exponential tool with a circular cross-section and a working end diameter of 10 mm.

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Tool δ. 3, which was an exponential tool with a steel hardened tip for spe- cial use with a working end area of 150 mm.

Table I shows how the resonance frequency, the cost of production and the tool life of the individual tools mentioned above were affected by the method of the invention.

Table I

Tool number: Change the resonant frequency after melting the layer Increase production oeny tools by applying a layer Extending tool life by coating 1 .... i «................... ...... 6% .......... 19 x 2 .... .... 1 «................... ...... 10% .......... 100 x 3 .... .... 1% ................... ...... 3%

The ultrasonic tools provided by the method according to the invention make it possible to improve the weldability while saving time and energy compared to known ultrasonic tools.

Table II lists the advantages in the welding of fabrics by the aforementioned dies No. 2 in comparison with the same tool but not modified by the method of the invention.

Table II

Fabric Weldable Tool No. 2 Saving Time Saving Untrimmed Energy ^{* 1}

100% POP 128 g / m ² Good very good 30 » 50 » POLYNETTA 100% PAD Good very good 25 « 50 » 100 g / m ² ADRIOLA 100 »PNS Poor Good 50 % 70 » 90 g / m ² XALYPSO 67 »acetate neevařitelný Good and.

% PAD 90 m / m ²

Claims (2)

1. A surface treatment ultrasonic tool, for example for welding or forming various materials, bonding textiles, in particular nonwovens, introducing ultrasound into metal melts and into aggressive environments, characterized in that at least on its working lines The 197,995 is at least one layer of a metal, ceramic, metal-ceramic or synthetic coating material deposited by thermal plasma spraying. 2. The ultrasonic tool according to claim 1, wherein the refining material is alumina, titanium dioxide, a mixture of both of these acidifying agents, tungsten, tungsten carbide, cobalt tungsten carbide, calcium metazirconate and the like.