Welding ultrasonic

Ultrasonic Welding A quite efficient method is based on ultrasonic energy, particularly for the bonding of thin films. It is useful for polyester (Mylar) and others. The heating is very rapid. 

Ultrasonic welding is not normally considered to be a microjoining technique. However, the process can be used to join glasses and could be miniaturised. The principle of ultrasonic welding is illustrated in Fig. 10.2. 

Ultrasonic welding uses high-frequency ultrasonic acoustic vibrations to bond surfaces together. The ultrasonic frequency is commonly in the range of 20-40 kHz. The ultrasound is generated by an ultrasonic generator, and a piezoelectric converter transforms the ultrasound frequency into a mechanical oscillation. The booster-sonotrode unit intensifies the oscillation up to amplitudes of 10-20 pm. This amplitude of the horizontal oscillation is coupled 

A direct joining of glasses by ultrasonic welding is impossible. Glasses can be joined only by using an aluminium interlayer. 

Ultrasonic welding is used to assemble amorphous and semicrystalline thermoplastic components that have joints that are butt, lap, tongue and groove, and shear. The typical ultrasonic normal vibration in the range of 15-70 kHz and 10-50 pm oscillates two mating components to create the weld. The amplitude of vibration generates the heat required to melt and flow the joint and is thus polymer dependent. Ultrasonic 

Transducer housing and conb ols for amplitude and duration of ultrasound. Also provides pneumatic pressure 

Tool attached to horn which conducts ultrasonic vibrations to workpiece 

Thermoplastics have two properties which make them particularly suited to ultrasonic welding (a) low thermal conductivity and (b) melting or softening temperatures of between 100 and 200 °C. As soon as the ultrasonic power is switched off the substrate or bulk material becomes a heat sink, giving rapid cooling of the welded joint. When more traditional conductive heating is used for welding however the thermal 

Ultrasonic welding is not only restricted to plastics but can also be used for metals. 

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N.Nielsen, P-scan system for ultrasonic weld inspection . The Danish Welding Institute, 1980. 

CAMUS - A Novel System for Operator Based Ultrasonic Weld Inspection. 

ISONIC - Complete Ultrasonic Weld Inspection Documentation by Continuous Recording of Manual Probe Manipulations, Acoustic Coupling and Echoes. 

ISONIC - the intelligent ultrasonic weld test system... 

Facts that will revolutionize manual ultrasonic weld testing... 

G. Passi und S. Passi MUTOS Equipment for increasing reliability of ultrasonic weld inspection. International Conference Advanced Technologies in Welding and nondestructive examination. Proc., Tel-Aviv, 1993, p 32-34... 

Ultrasonic Welding. Ultrasonic welding has been appHed to Tefzel with weld strength up to 80% of the strength of the base resin. Typical conditions include a contact pressure of 172 kPa (25 psi) and 1—2 s cycle time. The two basic designs, the shear and butt joints, employ a small initial contact area to concentrate and direct the high frequency vibrational energy. 

When this type of flow pattern is impractical, an alternative may be a through hole or tube formation combined with a postmolding sealing or closing operation by spinning or ultrasonic welding. At the other extreme, consider a 1 /4 in. (0.6 cm) diameter core exposed to a pressure of 4,000 psi (28 MPa) with an allowance for deflection of 0.0001 in. (0.00025 cm) and determine how deep a blind hole can be molded under these conditions. 

Thermoplastics Mechanical Fasteners Adhesives Spin and Vibration Welding Thermal Welding Ultrasonic Welding Induction Welding Remarks... 

Table 8-43 Plastics behavior with ultrasonic welding...

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. 

There are at present only a few commercial applications of ultrasound in the plastics industry. The best knovm is probably the welding of thermoplastics, a process which now lends itself readily to automation. In common with the welding of metals, the ultrasonic welding of plastics is primarily a hot stage. In the process ultrasound is applied to two layers of plastic, heat is generated at the interface causing the material... 

Encapsulation of Hazardous Materials by Ultrasonic Welding. The methods are described in Refs 1, 3 Si 4 with abstracts given in Refs 2 5... 

Jr, "Ultrasonic Weld Encapsulation", Ordn 55, July-Aug 1970, pp 68-70 5) Expls ... 

Ultrasonic welding, used increasingly in the aerospace, automotive, electrical, and electronics industries. The process requires simpler surface preparation and less energy and allows welding of thinner sheets to thicker structural members. 

PIEZOELECTRICITY. Electric energy created by application of pressure to ceramics of plastics. Devices utilizing this phenomenon are gas flame igniters, ultrasonic welding tools, and sonar navigation aids. 

Besides acrylics or PMMA, injection molding was also carried out on regular and optical-quality PC chips [187]. Furthermore, three PS plastic plates were injection molded to create the microfluidic channels, which were employed for a biomolecular interaction study. The upper plastic plate with ridge patterns was ultrasonically welded to the middle plate. The middle plate was sealed to the bottom plate with a molded silicone rubber layer [188],... 

Welding of ETFE parts can be done easily by spin welding, ultrasonic welding, and conventional butt-welding using flame and ETFE rod. The resins bond readily to untreated metals, but chemical etch corona and flame treatment can be used to increase adhesion further.21... 

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