All thermoplastic resins can be welded using ultrasonics. Best are hard, amorphous plastics such as PC, PS, SAN, ABS, and PMMA. They have ideal transmission properties for ultrasonic energy, thus they are also easily weldable and achieve good results even with larger dimensions. Semi-crystalline plastics, such as PA, PP, PE, and POM melt generally faster. Consequently they can only be welded within the near field of the sonotrode (weld tool).