General, Research, Technology

Ultrasonic welding: what is it and how does it work?

At the time of this writing, the CoVID-19 pandemichas led to a shortage of protective masks worldwide. As part of the fight against coronavirus SARS-CoV-2, some companies are changing their usual production and begin to manufacture personal protective equipment (PPE). So, in March of this year in China Foxconn was the leader in the production of protective masks. Since coronavirus is now raging in Europe, Russia, the USA and many other countries of the world, the largest global companies are following in the footsteps of Foxconn, but not all can withstand it. So, the Italian company Miroglio, specializing in the production of ready-made clothes and fabrics, recently announced the termination of the production of masks. But the German company Weber Ultrasonics, which develops components for ultrasonic welding, does not produce masks, but their technology is crucial for PPE manufacturers around the world. It is for this reason that close attention has been paid to ultrasonic welding technology today. In this article, you will find out what kind of technology it is and how it works.

Today it is quite difficult to find industries that do not use ultrasonic welding

What is ultrasound?

Ultrasound Are sound waves that travel inspace like photons of light. However, unlike light waves that can propagate in a vacuum, ultrasound requires an elastic medium, such as a gas, liquid, or solid, to propagate. It is noteworthy that the human ear perceives a limited frequency of sound waves, and by ultrasound, scientists understand frequencies above 20,000 hertz. Despite the fact that the existence of ultrasonic waves has been known since 1883, its practical use began not so long ago. So, in 2020, technologies using ultrasound are used almost everywhere. And in the wild, ultrasonic waves help to detect obstacles, navigate in space and communicate with dolphins, bats, whales, tarsiers and rodents. Also, ultrasonic waves are found as components of natural noise, for example, in the noise of rain, wind, waterfall and in the sounds that accompany lightning discharges, etc.

Ultrasonic welding - this is a technology by which fabrics (without threads and glue) and many other materials are connected, including plastic and metal.

What is ultrasonic welding for?

Despite the fact that before the coronavirus pandemic, few people thought about this, but ultrasonic welding technology has long been used for the manufacture of hygiene and medical products from polypropylene - material based on nonwoven materials. Thus, the German company Weber Ultrasonics does not yet produce protective masks, but their ultrasonic welding systems are crucial for mask manufacturers. Mostly, this was the case before the CoVID-19 outbreak, however, since the beginning of the pandemic, the company has faced a growing demand for components for ultrasonic welding. This is reported by Christian Unser, chief commercial officer of Weber Ultrasonics:

Worldwide economic situation todaycritical, but companies like ours are doing well. We are already working with mask manufacturers and many of them are contacting us to purchase ultrasonic components, such as generators, accelerators and transducers, etc.

So what is this ultrasoundprocess? For all the apparent complexity, ultrasonic welding is actually a simple process. The source of energy is ultrasonic vibrations that act on the connected parts. In our case, the fabrics are gathered together under slight pressure. In addition to fabrics, these can be any other materials.

If you do not go into detailsthen through two pieces of material that you needweld together, high-frequency sound waves (ultrasound) are transmitted. They heat the material and, due to their vibration, create friction between the parts. Thus, both parts penetrate each other and are welded together. And to make it even easier, imagine two marshmallows that you lightly heated on a stove and connected together. Here the principle is the same, only heating and friction are achieved by ultrasonic waves.

Two parts are laid on top of each other, pressed and pressed tightly, then ultrasound is passed through them, they wait a bit and everything is ready.

Ultrasonic welding, laminating, cutting and embossing of non-woven and web materials offers numerous advantages over other gluing methods. But which ones and why?

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The benefits of ultrasonic welding

Ultrasonic welding is possible in hard to reach places, and
the absence of harmful emissions makes this process safe for health

Modern ultrasonic welding is very fast. It takes only about a quarter of a second to form a compound, so it is suitable for mass production of all types of protective masks, hygiene products and PPE, such as surgical masks. The good news is that the company in Germany - despite a difficult epidemiological stop - is working on a 3D printer for printing protective and surgical masks.

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However, some manufacturers of ultrasoundthe equipment still cares - the availability of raw materials and non-woven materials, which may soon end. Nevertheless, we at the editorial board of hope that this will not happen and that there will really be enough protective masks for everyone, especially employees of medical institutions. Well, we can easily make protective masks from improvised materials. Read about how to sew a mask or even do without a thread with needles in our material. Be healthy!