Ultrasonic welding techniques

Seals required on the membrane elements vary with the membrane type and the module geometry. Many flat-fihn designs employ thermal and ultrasonic welding techniques and thereby avoid the introduction or minimize the use of dissimilar seating materials. 

TPEs can be bonded to other materials by adhesive, heat bonding, electromagnetic filling, radio frequency, heat-sealing lamination, friction and spin welding, and ultrasonic welding. For TPUs, the most widely used techniques are radio frequencies, and ultrasonic and hot stamping. A few typical applications include football bladders, valves, and conveyer belts. 

Ultrasonic relaxation loss, of vitreous silica, 22 429-430 Ultrasonics, for MOCVD, 22 155 Ultrasonic spectroscopy, in particle size measurement, 13 152-153 Ultrasonic techniques, in nondestructive evaluation, 17 421—425 Ultrasonic testing (UT) piping system, 19 486 of plastics, 19 588 Ultrasonic waves, 17 421 Ultrasonic welding, of ethylene— tetrafluoroethylene copolymers,... 

Welding is easy using thermal processes and possible by the high-frequency technique if the VA content is above 13%. Ultrasonic welding is suitable for thin parts. 

Plastic sections, which are too thick to be heat-sealed, may usually be welded. There are three major methods in commercial use heat, solvent, and ultrasonic. In general, these methods are limited to use with thermoplastic materials. These welding techniques have done much to lower the total cost of using plastics in the construction and other industries. 

The ultrasonic welding of ETFE can be achievedl" with a weld factor of 0.8. The success of this technique is dependent on joint design and welding parameters such as the contact time and pressure. Typical welding conditions include a contact pressure of 170 kPa and a cycle time of 2 secs. 

Ultrasonic welding the two basic techniques are plunge welding and continuous welding. In plunge welding, the parts are placed under a tool or horn the horn descends to the part under moderate pressure and the weld cycle is initiated. In the continuous welding process, the horn may scan the part or the material is passed over or under the horn on a continual basis. 

Polyethersulphone can be machined, ultrasonically welded and solvent welded using standard techniques. Components can also be vacuum met2GJ.ised, electroplated and painted. 

For film adhesives, ultrasonic welding (112) at a frequency of approximately 15,000 kHz can be used instead of weld-bonding. The subsequent curing can also be completed in a regular oven. This technique has been applied to small... 

Polystyrene can be joined by either thermal or solvent welding techniques. Preference is generally given to ultrasonic methods because of its speed and simplicity. However, heated tool welding and spin welding are also commonly used. 

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