The role of the power supply is to convert the incoming line voltage (at 50 or 60Hz) into a new frequency. This electrical energy then is sent to the converter, which as the name implies, converts the electrical energy into mechanical vibrations. The converter consists of piezoelectric ceramic discs, which expand and contract at the rate of the supplied electrical energy. The magnitude of the vibrations is referred to as amplitude, a term that becomes very important when specifying an ultrasonic system for a given application. The vibrations then are transmitted through the booster, which typically increases the amplitude by a predetermined multiple, also known as gain. Finally, the booster’s output amplitude is transmitted through the horn, where it then can be delivered to the plastic parts.
Ultrasonic welding machine composition
An ultrasonic generator (power supply)
Ultrasonic power is divided into two kinds of simulation and numerical control, hcsonic adopts numerical control power has more advantages.
- Track the primary resonance
During ultrasound operation, as the temperature, power, and load change, the frequency of a resonance may shift, and the ultrasound generator can automatically follow this frequency shift.
- Lock onto the primary resonance
All ultrasonic systems have a primary resonance. In addition there will be secondary (spurious) resonances. When the power supply starts, it must lock onto the primary resonance and ignore the secondary resonances.
- Auto-adjust amplitude
Most applications can be best controlled by controlling the output amplitude rather than the power. amplitude should be regarded as the independent (input controlled) variable and power should generally be regarded as the dependent (output resultant) variable.
An ultrasonic converter (transducer)
The ultrasonic converter utilizes the high frequency electrical signal from the generator and converts it into linear, mechanical movement，This conversion ccurs through the use of piezo-electric ceramic disks.
piezoelectric transducers for power ultrasonics are of the Langevin type — i.e., one or more piezoceramics that are mechanically compressed (prestressed) between a front driver and a back driver.
An ultrasonic booster
An ultrasonic welding tool (horn/sonotrode)
Sectional view of ultrasonic welding machine WW2020L
Longer service life
All piezoelectric transducers for ultrasonic welding are of the Langevin type — ie, one or more piezoceramics that are mechanically compressed (prestressed) between a front driver and a back
Because piezoceramics are weak in tension, a static compressive prestress must be applied to prevent the piezoceramics from ever experiencing tensile stresses when the transducer vibrates ultrasonically. In addition, the prestress assures that the piezoceramic interfaces make good contact so that the acoustic waves transmitt well with minimum loss. We use the most convenient center screw design.
A specific prestress can be obtained by tightening the transducer center screw to tighten the transducer. The traditional method is to use a torque wrench for tightening, but this parameter is
affected by many factors and often has deviations.
When the tightening of the ultrasonic transducer is insufficient, its impedance is large, which will cause serious heat generation; when the tightening is excessive, it is easy to cause problems such as damage to the ceramic sheet (crystal crack) and durability. Transducer is the most important part of ultrasonic welding equipment. So it is very important to accurately tighten the transducer and obtain the best prestress.
Piezoelectric ceramic sheet
Piezoceramics are typically classified as “soft” or “hard”. Hard piezoceramics are used for power applications. Among hard piezoceramics there are two basic types, generally designated as PZT4 and PZT8 (PZT stands for lead-zirconate-titanate of which the piezoceramics are composed). Different manufacturers may have their own designations for these types but the general performance is similar. Our device uses PZT8 piezoelectric ceramics, which has better relative performance.
Advantages of ultrasonic welding
- Does not need external heat source: The primary advantage of ultrasonic welding is that it doesn’t need an external heat source. The heat is self-generated between the materials.
- Fast: Since the frequency of vibrations is very high, ultrasonic welding is one of the fastest welding methods available in the industry.
- Possibility of automation: Ultrasonic welding being uncomplicated in many ways, it is easy to automate. The ultrasonic machine comes with sensors that constantly monitor the temperatures.
- Clean and strong joint: The contact surfaces melt/fuse upon welding, and it produces a very clean and strong joint.
Ultrasonic welding has many advantages when compared to traditional welding technologies. Many industries use ultrasonic welding due to these specific combinations of merits.
Ultrasonic mask welding
Application of ultrasonic welding
Ultrasonic welding is an eco-friendly process that takes seconds, consumes very little energy and reduces costs while maintaining a high degree of quality. The equipment fuses contact points on cell phones and other consumer electronics that are generally inaccessible with other welding methods. These techniques can be adapted to a wide range of commercial and industrial applications. In the food industry, the ultrasonic welding process is used to create a hermetic seal. It can fasten blister packs and facilitate the manufacturing of a variety of products, including toys, disposable lighters , pipettes and intravenous catheters.
Ultrasonic welding is commonly used in the plastics, aerospace and automotive industries to join similar materials. It is particularly useful in the production of medical products. Since the process does not introduce exhaust or other contaminants and the welds do not degrade, the manufacturing equipment can be used in a clean-room environment.
Ultrasonic welding tips
|Maximum Power output||2200W||Frequency||20KHZ|
|Maximum Amplitude||10µm||Working model||Continuous, intermittent|
|Weldable materials||Thermoplastic materials||Welding Head Material||Al,Steel|
|Welding Head Size||110*20 or 150*40mm||Driven Type||Electric|
|Technical Support||Video, mail, phone||Warranty||One year, except horn|
|Full Set Weight||10KG||Place of Origin||China|