What are the advantages and disadvantages of ultrasonic welding? How does ultrasonic weld plastic and metal---Pinghe ultrasonic spot melting machine

What are the advantages and disadvantages of ultrasonic welding? How does ultrasonic weld plastic and metal---Pinghe ultrasonic spot melting machine

Did you know that high frequency sound can be used to bond materials? Ultrasonic welding technology is used to assemble products in many industries, from medical devices to sports shoes to automobiles. There are many welding methods, and ultrasonic welding is one of the most modern welding methods. Today, the editor of Xianji.com will introduce the principle, advantages and disadvantages and application of ultrasonic welding to you. ---Pinghe ultrasonic spot melting machine

What is ultrasonic welding?

Often, you can connect different materials with fasteners such as nails, screws, or threads, and this works with metal, wood, fabric, and plastic. Many plastics use glue, which forms a chemical bond between the glue itself and the surface of the plastic material being bonded. Metals can be bonded together by heating other metals to act as binders, such as lead solder in electrical connections. Alternatively, the metals can be melted directly together, and once the surface of the melted metal cools, the metals join together. Welding usually requires an open flame or torch to achieve the high temperatures necessary to melt the metal surface. Therefore, welding is an expensive process for some manufacturing industries.

A new and more economical welding method was introduced in the 1940s - ultrasonic welding. Ultrasonic welding technology uses the vibration of high-frequency sound waves to join different materials together. By applying ultrasonic vibrations to the contacts, the high-frequency vibrations cause the material to melt. The typical frequency range used in ultrasonic welding is between 15 and 40 kHz. ---Pinghe ultrasonic spot melting machine

Besides requiring less energy than conventional welding, one of the biggest advantages of ultrasonic welding is that it can be used on materials other than metals, such as thermoplastics. Ultrasonic metal welding technology developed from the 1950s to the 1990s as the electronics in the equipment became more sophisticated and computers could control the entire process. Since then, the technology has been applied to plastic products and has become popular in the plastics industry.

In addition, ultrasonic welding equipment can concentrate vibrations in very localized locations, so welding is very precise.

Ultrasonic welding machine composition

Ultrasonic welding machines were created to efficiently convert electricity into mechanical vibrations. The machine is equipped with a microprocessor to read the temperature and adjust the heating accordingly. Ultrasonic welding equipment has four main parts. ---Pinghe ultrasonic spot melting machine

Power supply: High frequency ultrasonic welding machine requires high voltage power supply.

Transducer: The transducer absorbs high voltage current and converts it into high frequency vibration.

Booster: It works like an amplifier, it absorbs high frequencies and then makes it more powerful.

Horn or sonotrode: is the medium between the welding material and the machine. It concentrates ultrasonic vibrations to a local point.

The power supply converts low frequency electricity (50-60 Hz) to high frequency electricity (20-40 kHz; 1 kHz = 1000 Hz). Next, a transducer or converter converts high frequency electricity into high frequency sound (ultrasonic waves). The booster makes the ultrasonic vibrations bigger. Finally, a horn or sonotrode focuses the ultrasonic vibrations and transmits them to the material to be welded. In addition to these parts, there is an anvil on which the welding material is stacked and held. There are also ways to apply force (usually air pressure provided by a pneumatic piston) to hold the materials together during the welding process.

How does ultrasonic welding melt materials?

Ultrasonics are used in welding to provide small but fast vibrations. When the sonotrode is attached to the material, the ultrasonic vibrations will cause the material to vibrate back and forth for about half a millimeter or so. ---Pinghe ultrasonic spot melting machine

Such tiny movements are enough to melt the material because the rate of vibration is quite high. These vibrations cause materials to rub against each other, and that friction generates heat.

You can recreate a similar environment with a quick rub of your hands. You can feel the heat generated between your palms.
Also, if you continue to rub quickly, it can get very uncomfortable. Imagine the heat generated inside as materials rub against each other at speeds imperceptible to the human eye!

Friction raises the temperature to the point where the contact points between the materials melt, paving the way for molecular bonding. That's how ultrasonic welding of plastic is done. ---Pinghe ultrasonic spot melting machine

However, it is slightly different when welding metals. Ultrasonic welding is used to heat the metal to one third of its melting temperature.

At this point, the molecules between the two metals move toward each other, forming strong molecular bonds. Metal didn't melt.

Why use the ultrasonic welding method?

Advantages of ultrasonic welding

Ultrasonic welding offers many advantages over traditional welding techniques. Due to the combination of these advantages, many industries use ultrasonic welding. ---Pinghe ultrasonic spot melting machine

No external heat source required: The main advantage of ultrasonic welding is that no external heat source is required. Heat is self-generated between materials.

Fast: Due to the very high frequency of vibration, ultrasonic welding is one of the fastest welding methods in the industry.
Automation Possibilities: Ultrasonic welding is uncomplicated in many ways and can be easily automated. This ultrasonic machine has sensors that continuously monitor the temperature. ---Pinghe ultrasonic spot melting machine

Clean and strong joints: The contact surfaces melt/fuse when soldering, resulting in very clean and strong joints.
Things to Remember When Using an Ultrasonic Welder

Ultrasonic welding is very effective for sealing and welding plastics. However, you cannot weld all types of plastics.
Like metals, plastics come in different types. It is also very important to ensure that the plastics being welded are chemically compatible.

If you try to weld polyethylene and polypropylene, it may melt together, but there will be no chemical bonds. Chemical bonds are important to create strong welded joints. ---Pinghe ultrasonic spot melting machine

Another factor to keep in mind when ultrasonically welding any material is maintaining an even area of contact. When welding metals, ultrasonic vibrations propagate parallel to the plane.

Disadvantages of ultrasonic welding

As with all joining processes, ultrasonic welding has some disadvantages.

Lap Joints Only: Ultrasonic welding should only be used for lap joints. It cannot be used with other types of joints as it will require a specially designed corner and clamp. ---Pinghe ultrasonic spot melting machine

Limit the welding area: We have discussed how ultrasonic welding can produce highly localized welds. Therefore, you cannot expect soldering to provide joints with an area larger than 250x250mm2.

Cannot weld thick and hard metals: Thick and hard metals do not vibrate as much as thin and soft metals. This prevents them from mechanically vibrating.

Application of Ultrasonic Welding

Ultrasonic welding is used in many fields. One of the best examples of using it is in sneakers. Ultrasonic welding produces a better finish than stitching or gluing. ---Pinghe ultrasonic spot melting machine

The material in the upper part of this New Balance sneaker is assembled by ultrasonic welding rather than traditional sewing methods.

Ultrasonic welding of thermoplastics is very common in the medical industry, the automotive industry and the household appliance industry. Since no additional material is required to secure the bond, ultrasonic welding does not add to the overall weight of the finished product.

Ultrasonic welding was a technique in the 1940s, but it is still the welding method of choice for creating a clean and strong bond between dissimilar materials. Ultrasonic welding is still evolving to expand its use. ---Pinghe ultrasonic spot melting machine

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