Last Updated on January 8, 2022 by Luis Ferency
Ultrasonic welding, often known as USW, is a type of welding that employs acoustic waves that are over the hearing range. Elevated power is converted into a fast movement to complete the operation. Friction force energy is transported at the plastic contact region when mechanical movements and power are given. The plastic melts, producing a chemical connection between the components. This method is ideal for welding thermoplastics since it is quick, inexpensive, and simple to control.
Ultrasonic welding is often modern manufacturing, though manually filling ultrasonic welding machines still exist. A converting machine or electromechanical converter, which generates oscillations from current, is a standard component for every simple ultrasonic welder. That vibration is generally manually increased with an amplifier. A bell and hammer are used to drive vibrations to the intended portions. A control system controls the ascending and descending motion of the machine, which can be electronically powered, to bind the pieces together before the weld has melted.
The entire machine is driven by electricity, which further provides the right amount of electricity for the inverter.
How Does Ultrasonic Welding Work?
Working
Ultrasonic vibrations with a frequency range: 20,000- 40,000Hz are used to connect two plastic parts firmly. The elevated vibration creates thermal energy and burns the substance at the contact of the 2 components. On chilling and crystallization, the molten materials fused to produce a robust weld.
Now, Let’s discuss some of the main parts of this welding machine to clarify the understanding image for you:
Main Components
Press Machine
The welding equipment is held in place by the press, which also applies pressure to the workpiece material. It consists of a base tray for holding the cooling apparatus and an air compressor for precisely controlling the force. A gauge and controller are also included in the press for regulating the welding power. The functioning of gauges is dependent on the welding power of the machinery. To correctly compare a machine’s welding pressures, a local cell must be used to regulate its welding power.
Supporting Tool
It’s a gripping mechanism that holds and attaches the 2 plastic items firmly. It provides higher vibration to be delivered to the two parts’ contact.
Horn
It shakes at a high rate, and the mechanical quivering is transmitted to the two components to be bonded. It also manually alters the loudness. It adopts the form of the component. Aluminum is used to make the horn.
Booster
This component has two major functions: it amplifies and transmits the vibrations generated at the inverter’s tip to the horn. It also serves as a foundation for putting the pile on the press. The power from the Inverter causes the booster to expand and compress, amplifying the waves.
So, these were some of the main parts of the ultrasonic welding machine. Now, Let’s discuss its applications:
Wide Range Of Uses
Ultrasonic Welding is used in many fields due to its welding quality and advantages. Some of the applications are detailed below.:
Medical
Ultrasonic welding is used in the medical field because it reduces weld deterioration. As a result, the approach is employed in the manufacture of specialist cleaning equipment for apartments. Ultrasonic welding mechanization allows for precise management of dimensional accuracy, avoiding bioactivity of the welded components. This decreases the manufacturing costs without considering the quality of the functions.
Car Sector
Ultrasonic welding is used to join big polymers and electronic parts in the care sector. panels, circuit boards, driving knobs, air vents, furniture, and gearbox are among such parts. Ultrasonic welding is preferred by welders in this business because of its cheap operating costs, versatility, short cycle durations, and mechanization. The technique is also non-destructive to the surface finish. This is because the elevated vibrations prevent markings on the produced pieces from forming.
Aerospace
Ultrasonic welding is applied throughout the aerospace sector to connect gauge materials and other small plane components like LEDs. Ultrasonic welding is also helpful for metals such as aluminum, which is frequently utilized in the manufacture of various airplane components
Pros & Cons Of Ultrasonic Welding
We have already discussed its working, main parts, and its uses. When it comes to its benefits and drawbacks, then:
Pros:
Ultrasonic devices have a reputation for being long-lasting. You can conduct bulk welding with minimum failures and defects once they’ve been developed and deployed. You could manage the welding operation to decrease human interference relying on your welding task. It will save operating expenses while also improving weld quality.
Working Speed
Ultrasonic welding heats, welds, and cools via quickly increasing ultrasonic sound vibrations. All of these operations happen quickly, allowing you to weld many items in less time. Once you utilize ultrasonic welding, you may imagine a significant output and quick turnaround duration.
Safety
Ultrasonic welding is an extremely safe method of joining metals. The technique employs highly focused energy, which decreases welder damage. Welding temperature is confined, low, and fast dispersed to the needed welding connections and substances. The welders and the surroundings are not harmed in any way throughout this procedure.
Low Expense
Welding projects take a little time, cost, and materials to accomplish because the procedure is quick. Associative nuts and sticky materials are not required in the welding process. As a result, you save a lot of money on materials. Ultrasonic welding produces a clean finish with little wastage because of its great accuracy.
Welding Quality
Ultrasonic welding’s accuracy ensures high-quality connections. There will be no plastic bursts, bending moments, or defects in such junctions. The end effect is a smooth, nearly undetectable seam that requires no retouching.
Cons
Although ultrasonic welding provides benefits, it does have disadvantages that may limit the efficacy of a welding operation. The following are among the method’s drawbacks
Materials
Though ultrasonic welding works very well with substances, it still does not function properly with some thermoplastic materials. Ultrasonic welding is inefficient when using thermoplastics with high water. Welding stiff and durable thermoplastics is also not possible with this approach
Investment
Ultrasonic welding techniques and devices are not inexpensive. The cost of robotic ultrasonic welding equipment continues to rise.
These were all the pros & cons of ultrasonic welding.
Conclusion
We have reached the end of this article. In this post, we have discussed the working, main parts, application, and pros & cons of ultrasonic welding. Do we hope you have found the answer to How Does Ultrasonic Welding Work?.

Luis Ferency with experience of 35+ years is a semi-retired welder. Though his passion for welding and learning keeps him going further. He loves sharing his knowledge on his expertise in SMAW, GMAW, GTAW, and FTAW. Hence, this helped the new welders to seek leverage knowledge and improve their welding skills.