Transducer and method for mounting the same
A transducer is provided that comprises a horn having a longitudinal axis, a bonding tool attached to the horn, and an ultrasonic generator attached to the horn and spaced from the bonding tool along the longitudinal axis of the horn. A flexure is attached to the horn between the bonding tool and the ultrasonic generator for supporting the horn whereby to increase its dynamic rigidity in directions transverse to the longitudinal axis.
1. A transducer comprising:
a horn having a longitudinal axis;
a bonding tool attached to the horn;
an ultrasonic generator attached to the horn and spaced from the bonding tool along the longitudinal axis of the horn;
a mounting portion for mounting the transducer, the mounting portion being in direct contact with the horn and located between the bonding tool and the ultrasonic generator; and
a flexure attached to and in direct contact with a cylindrical portion of the horn, the flexure being attached to and in direct contact with the horn between the bonding tool and the mounting portion for supporting the horn,
wherein the flexure is formed from a sheet of material, and completely surrounds a circumference of the cylindrical portion of the horn,
the mounting portion does not contact the flexure, and
the mounting portion comprises a holding flange and a clamping portion.
2. The transducer as claimed in claim 1 , wherein the flexure has a relatively low stiffness in directions parallel to the longitudinal axis and a relatively high stiffness in directions transverse to the longitudinal axis.
3. The transducer as claimed in claim 2 , wherein the flexure is operative to reduce transverse oscillation caused by low cycle fluctuating forces during motion of the horn.
4. The transducer as claimed in claim 2 , wherein the stiffness of the flexure in directions parallel to the longitudinal axis of the transducer is 10-500 N/m and the stiffness of the flexure in directions transverse to the longitudinal axis is 500-3000 kN/m.
5. The transducer as claimed in claim 1 , wherein the ultrasonic generator is operative to generate ultrasonic vibration along the longitudinal axis of the horn in the form of a standing waveform, and the flexure is located at a nodal point of said waveform.
6. The transducer as claimed in claim 1 , wherein the horn is comprised of separate components and the flexure is sandwiched between the separate components for attachment to the horn.
7. The transducer as claimed in claim 1 , wherein the ultrasonic generator and horn are configured to be operable in at least two ultrasonic frequency modes for ultrasonic bonding by the bonding tool.
8. The transducer as claimed in claim 1 , further comprising one or more additional flexures attached to the horn between the bonding tool and the ultrasonic generator.
9. The transducer as claimed in claim 1 , wherein the flexure is formed from a cutout profile from a sheet of flexible material.
10. The transducer as claimed in claim 9 , wherein the flexure comprises strips of flexible material formed from the sheet of flexible material.
11. The transducer as claimed in claim 10 , wherein the strips of flexible material project radially from a centre of the flexure.
12. The transducer as claimed in claim 1 , wherein the flexure has a thickness of between 0.05 mm and 0.15 mm.
13. The transducer as claimed in claim 1 , further comprising a oscillation measuring device for determining an amplitude of displacement of the flexure in real time during operation of the transducer.
14. The transducer as claimed in claim 13 , wherein the oscillation measuring device comprises a laser vibrometer that is operative to measure a displacement amplitude of the flexure.
15. The transducer as claimed in claim 13 , wherein the oscillation measuring device comprises a strain gauge mounted on the flexure that is operative to measure an induced strain on the flexure during oscillation for determining the amplitude of displacement of the flexure.
16. The transducer as claimed in claim 13 , further comprising a closed-loop control system for receiving feedback concerning the amplitude of displacement of the flexure and for controlling an amount of power fed to the ultrasonic generator.
17. A transducer comprising:
a horn having a longitudinal axis;
a bonding tool attached to the horn;
an ultrasonic generator attached to the horn and spaced from the bonding tool along the longitudinal axis of the horn;
a mounting portion for mounting the transducer, the mounting portion being in direct contact with the horn and located between the bonding tool and the ultrasonic generator; and
a flexure attached to and in direct contact with the horn between the bonding tool and the mounting portion for supporting the horn,
wherein the mounting portion does not contact the flexure, and,
the mounting portion comprises a holding flange and a clamping portion, the holding flange being directly connected to the clamping portion, the clamping portion extending in a longitudinal direction parallel to the longitudinal axis of the horn, the horn being cylindrical along the length of the clamping portion, the clamping portion being a cylindrical barrel completely surrounding the cylindrical portion of the horn along the length of the clamping portion.