La ultrasonic welding of thermoplastic materials represents one of the most reliable and precise technologies for the assembly of components in the microelectronics and the sensors. In areas where small dimensions, minimal tolerances and absolute cleanliness are essential requirements, ultrasonic welding allows a permanent bond, free of glues, solvents or contaminants, ensuring stable and long-lasting performance.
What is ultrasonic welding
Ultrasonic welding is a technique that uses high-frequency mechanical vibrations (typically between 20 and 40 kHz), transmitted to a plastic component via a sonotrode, to generate localised frictional heat. This heat melts the thermoplastics at the point of contact, bringing them together without the need for additional materials. In the specific case of microelectronics and sensors, the ultrasonic welding is applied for encapsulating circuits, joining protective shells, attaching micro-components or connectors, and - when necessary - also for precision cutting on thin films or plastic microstructures.Advantages of ultrasound technology
Compared to other welding or bonding methods, ultrasonic technology offers numerous advantages:- High precisionThe process can be adjusted very accurately in terms of pressure, time and power, making it ideal for electronic micro-components.
- Absence of chemical agentsno adhesives, solvents or other potentially contaminating materials are used, which is critical in highly sensitive industries.
- Process cleaningIt does not produce fumes, dust or processing residues.
- Speedwelding takes place in an extremely short time (a few seconds maximum).
- Repeatabilitywelding is easily automated and guarantees consistent quality over large production batches.
- Environmental compatibilityThe absence of waste or harmful substances makes the process sustainable and compliant with international environmental guidelines.
Applications in microelectronics and sensors
The fields of application are many and growing:- Assembly of environmental and industrial sensorsin which plastic protects electronic components from moisture, dust or chemicals.
- Capsulation of microchips in plastic enclosures for automotive, IoT or home automation applications.
- Union of shells and enclosures
- Ultrasonic cutting
- Welding of connectors for printed circuit boards, batteries or wireless modules.
Technical specifications: frequencies, power and machinery
For machining on components of small dimensions and thin materials, they typically employ 35 or 40 kHz ultrasound machineswhich offer a less aggressive and therefore more controllable vibration than 20 or 30 kHz. The powers employed range from 250100 to 6500 W, depending on the material to be welded (such as ABS, polycarbonate, polypropylene, polyethylene, nylon, polystyrene) and the complexity of the component. The ultrasonic welders for microelectronics can be manual, bench-top or fully integrated in automatic lines, with digital control systems allowing precise management of process parameters and real-time quality monitoring. For the ultrasonic cuttingsystem-integrated cutters are used, capable of performing clean, precise cuts on thin plastic materials, films or technical laminates, often combining welding and trimming in a single operation.Sonomax Srl's experience in the sector
With over 20 years of experience in the field of ultrasonic welding, Sonomax Srl is a benchmark for Italian and European industry. Thanks to a complete range of ultrasonic welders designed in-house, the company is able to meet the specific needs of manufacturers of sensors, circuits, smart devices and industrial microelectronics. Sonomax offers:- Personalised consulting for frequency and power selection according to the application.
- Prototyping and testing on samples provided by the customer.
- Design of automated systems for high-efficiency production lines.
- Rapid maintenance and technical support throughout Europe.
- Training of operational staff to ensure autonomy and safety of use.
Frequently asked questions (FAQ)
Is it possible to solder electronic components without damaging them?
Yes. The ultrasonic process is localised and controllable: it does not produce diffuse heat and does not damage circuits if designed correctly.
Which plastic materials are best suited to sensor welding?
The most common are ABS, polycarbonate, polypropylene and nylon. Sonomax provides assistance in the selection of compatible material.
How long does ultrasonic welding last?
The cycle takes on average between 0.1 and 1 second. The mechanical strength of the bond is comparable to that of virgin material.
Is it possible to automate the entire welding process?
Absolutely. Sonomax designs systems that can be integrated into production lines with PLCs, robots and quality control.
What is the difference between welding and ultrasonic cutting?
Welding joins materials by fusion, cutting separates them while keeping the edges sealed. In some cases, the two processes are combined.
For more information, please contact our technical team at Contacts.
