The transducer of the ultrasonic welding machine vibrates at the resonant frequency without a load, which can be approximated as a pure resistance. However, once working with a load, due to the change of the load, the equivalent circuit parameters of the transducer will change, and the actual working frequency is different from the resonant frequency of the power supply. At this time, the welding efficiency is low, the welding quality and effect are affected, and the welding machine is also easy to Damaged. Therefore, when designing the circuit, the automatic tracking of the resonant frequency must be considered.

     After determining the operating frequency, generally need to consider the size of the power. Each workpiece frequency can generally have several power levels. For example, the operating frequency of 20kHz, the power range of the ultrasonic welding machine provided by most equipment manufacturers is 1~5Kw. In most cases, the required power can be determined through experiments in the laboratories of suppliers, research institutions, and universities. If the required power cannot be determined theoretically in advance, it is best to select the maximum power to ensure that the device can meet the application requirements.

      The selection of ultrasonic welding machine equipment is a very complicated matter, and many factors must be considered at the same time. Therefore, the purpose of this section is to provide general guidance information that is helpful for selecting equipment. If you want to choose equipment, you should closely contact the ultrasonic welding experts or equipment suppliers and listen to their opinions.

      When choosing an ultrasonic welding machine, one of the key considerations is the operating frequency. The operating frequency range of most equipment on the market is 20khz~40kHz, and some equipment’s operating frequency is 10~70kHz. For ultrasonic molds/or thin-wall weldments, the use of lower amplitude will help reduce the resonance of the weldment, because most of the resonance can be Cause damage to the weldment. Increasing the operating frequency or increasing the vibration amplitude will increase the power loss in the polymer. Therefore, in most cases, using a higher operating frequency is the only available method to obtain lower amplitude and higher power.

      Similarly, when selecting equipment, it is necessary to determine whether the weldment is most suitable for plunge welding or continuous welding. If it is a stitched weldment, most equipment manufacturers have such standard equipment, and they can also provide other standard rotary anvils with many patterns. Most anvils are cut, sealed and welded. If the weldment requires a very wide continuous weld (from 130px to 3050px or more), special equipment must be designed.

      Other equipment factors include control level, amplitude control, amplitude profile and stored program control capabilities. For some applications, these options can improve welding quality and density. On the other hand, testing in the application laboratory can help determine which options are needed. It should also be noted that for most equipment manufacturers, it is possible to add more options for welding equipment after purchase.