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Ultrasonic welding of thermoplastics in the far‐field
Author(s) -
Benatar Avraham,
Cheng Zhang
Publication year - 1989
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760292312
Subject(s) - materials science , welding , ultrasonic welding , composite material , ultrasonic sensor , crystallinity , polypropylene , joint (building) , polymer , amorphous solid , acoustics , structural engineering , chemistry , physics , organic chemistry , engineering
In far‐field ultrasonic welding of plastic parts the distance between the ultrasonic horn and the joint is greater than 6 mm. This study investigated the farfield ultrasonic welding of amorphous (acrylo butadiene styrene and polystyrene) and semicrystalline (polyethylene and polypropylene) polymers. Far‐field welding worked well for amorphous polymers. Weld strength improved substantially with increasing amplitude of vibration at the joint interface. Increasing the weld pressure and/or the weld time also resulted in higher weld strengths. Far‐field ultrasonic welding was not successful for semicrystalline polymers. The parts melted and deformed at the horn/part interface with little or no melting at the joint interface. A model for wave propagation in viscoelastic materials, which was developed to predict the vibration amplitude experienced at the joint interface, indicates that increasing the length of the samples to a half a wavelength should improve the far‐field welding of semicrystalline polymers by maximizing the amplitude of vibration at the joint interface.