J. Tsujino

Ultrasonic rotary motor using a longitudinal-torsional vibration converter

The characteristics of ultrasonic rotary motors using a converter from longitudinal to torsional vibration are studied. To obtain a rotary motor with large torque, ultrasonic motors using some types of slitted longitudinal-torsional converters are proposed. The longitudinal-torsion vibration converter consists of cylinders with a diagonally slitted vibration-converting part. Ultrasonic motors consist of such a converter with a driving part at its free edge and a rotor part clamped statically to a driving surface. The direction of rotation of these ultrasonic motors may be reversed using higher-order vibration modes. Maximum torques obtained are over 110 kgf-cm using a 40-mm-diameter converter and over 170 kgf-cm using a 50-mm-diameter converter. The maximum efficiency of a 50-mm-diameter motor was 17% when the output torque was 120 kgf-cm. The efficiency can be improved by installing piezoelectric ceramic disks or transducers within the longitudinally and/or torsionally vibrating converter part.<<ETX>>

Detection of welding condition and welding characteristics of ultrasonic wire bonding using a complex vibration welding tip

The vibration locus-shape of the welding tip undergoes a change from linear to elliptical to circular or from linear to rectangular to square using complex vibration systems. Thin aluminum- or copper-wire specimens of 0.025- to 0.1-mm diameter were welded successfully using the complex vibration systems. The required vibration amplitude and weld times are about one-half to one-third those of conventional wire-bonding systems. The weld strength was independent of the direction of wire length with this method. To detect the weldment condition during the welding process, the welding-tip vibration signal through the weldment and the acoustic emissions from the weldment are measured by a PZT detector under a lower welding specimen or an anvil. These detected signal changes correspond to weldment conditions.<<ETX>>

High frequency longitudinal-transverse complex vibration systems for ultrasonic wire bonding

High frequency longitudinal to transverse complex vibration systems of 160 kHz to 1 MHz for ultrasonic wire ball bonding for IC or LSI are studied. Vibration systems of these high frequency and complex vibration welding equipments consist of transverse free-free complex vibration rod 7.0 mm in diameter, two longitudinal vibration systems for driving the transverse vibration rod and a ceramic capillary 1.5875 mm in diameter. Vibration distribution of capillary at high frequency up to 1 MHz is measured at the first time and the conventional capillary is revealed applicable at such high frequencies.

Load characteristics of ultrasonic rotary motor using a longitudinal-torsional vibration converter

The characteristics of an ultrasonic rotary motor using a longitudinal-torsional vibration converter of 15 mm to 60 mm in diameter are studied. To obtain ultrasonic motors with a simple structure and large torque, motors using a slitted longitudinal-torsional converter are proposed. The converters have rather simple structures and are driven using only a longitudinal vibration transducer. The vibration converters have 12 to 18 diagonal slits of 45 degrees, 0.5 mm and 1.0 mm width and 10 mm length. The ultrasonic motors designed consist of a vibration converter with a driving part at its free edge, and a rotor part pressed statically to a driving surface using corned disk springs. Maximum revolution over 550 r.p.m. were obtained when vibration converters 15 mm in diameter and 2.5 mm in slit depth of about 60 kHz in frequency, were applied. Maximum torques over 0.3, 11, 17 and 23 Nm were obtained when vibration converters of 15, 40, 50, 60 mm in diameter and of 56 to 23 kHz frequency, were applied.

Ultrasonic butt welding of aluminium, anticorrosive aluminium and copper plate specimens

Ultrasonic butt welding of thick metal plate specimens is studied. Welding specimens used are aluminium, anticorrosive aluminium, and copper plates of 6-mm thickness. These welding specimens are successfully joined end to end with specimen strength of about 100 MPa (pure aluminium) or 250 MPa (anticorrosive aluminium) using 26-kHz or 19-kHz butt welding equipment. An ultrasonic vibration source of 19 kHz uses eight bolt-clamped Langevin-type PZT transducers of 50-mm diameter. The power required for joining aluminium, anticorrosive aluminium specimens, and anticorrosive aluminium to copper specimens is found to be 1-3 kW/cm/sup 2/, 6-8 kW/cm/sup 2/, and 7-9 kW/cm/sup 2/, respectively.<<ETX>>

Ultrasonic Wire Bonding Using a Complex Vibration Welding Tip

Ultrasonic wire bonding using a complex vibration welding tip is proposed and studied to improve welding characteristics of ultrasonic wire bonding of thin various metal wires. The welding system designed consists of a complex transverse vibration rod driven by a 40 kHz and a 60 kHz ultrasonic longitudinal vibration systems. These vibration systems are driven simultaneously by independent vibration controllers and amplifiers. Welding specimens used are 0.05 mm to 0.15 mm diameter aluminum wires and 1.0 mm thick copper plates. These welding specimens are welded successfully by the complex vibration welding equipment. And also, using this method, the weld strength of wire bonding becomes independent to the direction difference between welding tip vibration and wire length.

Ultrasonic plastic welding using two 27 kHz complex vibration systems

Welding characteristics of ultrasonic plastic welding using two 27 kHz complex vibration systems vibrating in elliptical locus are studied. Complex vibration systems consist of one dimensional longitudinal to torsional complex vibration converter 20 mm in diameter, a stepped horn and a 27 kHz bolt-clamped Langevin type PZT longitudinal transducer. Using complex vibration welding tip, two-dimensional vibration stress can be induced in welding specimens. Welding specimens used were joined successfully by comple vibrations with smaller total vibration velocity amplitude and smaller deformation of the specimens compared with linear vibration.

Characteristics of ultrasonic bending of metal plates using a longitudinal vibration die and punch

The characteristics of ultrasonic vibration bending of pure aluminium and anticorrosive aluminium plates of 2.0-3.0-mm thickness using a 19-kHz longitudinal vibration punch and a 27-kHz vibration die are studied. Using an ultrasonic vibration punch or die, the spring-back angle decreases to zero under sufficient vibration amplitude of a die or a punch, the bending angle increases, and bending surface conditions are improved. The hardness of the specimen and elongation of the bending surface decrease, and the roughness of the bending surface is decreased by vibration. The radius of curvature of the bending part doubles compared to the bending part without vibration. The required vibration amplitude for these vibration effects varies due to the material and thickness of the specimen and the total vibration characteristics of the combined die and punch.<<ETX>>

Ultrasonic butt welding of large metal plates shifting welding tip driving position at regular spaces along the specimens

The welding characteristics of large metal place specimens using an ultrasonic butt welding system with a 15-kHz large capacity vibration source are studied. The vibration source has eight 15-kHz bolt-clamped Langevin-type lead zirconate titanate (PZT) transducers of 60-mm diameter driven by a 50- or 100-kW static induction thyristor power amplifier. Aluminium plates of 6-mm thickness and 100-mm to 400-mm width are successfully joined end-to-end by changing welding tip driving positions. The required input power is about 2.2 kW/cm/sup 2/. Aluminium and copper plate specimens were also joined successfully by about 4 kW/cm/sup 2/ input power.<<ETX>>

Ultrasonic vibration bending of metal plate specimens

Ultrasonic vibration bending of a thin metal plate using a 27-kHz-vibration V-type bending die is studied. The 27-kHz vibration die consists of a longitudinal-to-longitudinal vibration-direction converter, four bolt-clamped Langevin type PZT transducers of 50-mm diameter, and four stepped horns. The bending die vibrates vertically to the bending punch and specimen plate. The bending angle is about 90 degrees . Bending-metal specimens used are commercially pure aluminum, anticorrosive aluminum, mild steel, and stainless steel plates of 1.6-mm thickness. The bending angle increases slightly as the die vibration amplitude increases under the same static bending pressure.<<ETX>>