Ultrasonic welding machine can be distinguished into ultrasonic plastic welder and ultrasonic metal welder.Ultrasonic plastic welder means applied to joint plastic parts in different thermoplastic material, while ultrasonic metal welders means applied to joint metal parts, especially for metal wire/cable and line terminal, etc.
Ultrasonic welding machines can apply both analogue ultrasonic generator system and IGBT (digital) ultrasonic generator system basing on what customers like.

Ultrasonic Welders applies the ultrasonic systems to excite resonance of material molecules of parts to be welded and generate heating to melt the material at welding area, after which stop ultrasonic working and keep parts hold under high pressure until material cold to become re-solidification.

Normally, ultrasonic welder for plastic welding can be in 15KHz, 20KHz, 28KHz, 30KHz, 35KHz and 40KHz. The power can be from 300W to 5600W. But different ultrasonic frequency, the peak value of ultrasonic power output is different.
For metal welding, normally it is 20KHz 3000W~6000W or 30/35KHz max to 1200W.

When you select a ultrasonic welder, you need to consider your requirement in detail as below factors:
1. Parts measurement;
2. Parts geometric design;
3. Parts material;
4. Welding quality standard: A. welding strength; B.air-tightness; C. welding control precision; D. Outlook after welding;
5. The deformation of part moulding.
Also you need to consider your demand of machine function as below according to your actual need:
1. Manual tuning or automatic tuning;
2. Welding mode: A. time mode; B. energy mode; C. depth control mode; D. external trigger mode;
3. Amplitude control;
4. System protection;
5. QC management;
6. Frequency in-time self search or not;
7. Self protection.

Here we suggest you send  us your parts 3D data for our analysis before you finally decide ultrasonic welding machine specification you will purchase.