Here is the abstract you requested from the Wirebond_2011 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Multifilament Tether for Electric Solar Wind Sail|
|Keywords: Multifilament Tether, Electric Solar Wind Sail, wire-to-wire bond|
|An ultrasonic wire-to-wire bonding technique was developed to produce multifilament tether from 25-50 µm diameter Al wires. One hundred 20 km long tethers are needed in a full-scale Electric Solar Wind Sail. Our automated tether factory employs an industrial 60 kHz ultrasonic wire bonder featuring a customized 3 wire wedge to produce a 4-wire tether. So far 10 m 2-wire tether has been produced by bonding a 25 µm diameter loop wire to a 50 µm diameter base wire. Currently we work on the 4-wire tether fabrication technique as well as on quality assurrance based on non-destructive online laser-acoustic and contact-resistance probing of the wire-to wire bonds. Destructive pull testing serves as gold standard to assess the quality of the produced wire-to-wire bonds. We achieve 11.6 ± 0.8 g maximum sustainable pull force by using a customized bonding wedge. It features with grooves along the wire direction, large 51 µm front and back radii in the foot. We also employ a specially designed wedge to hold the 50 µm wire firmly in place during the bonding. Our current bonding speed is 6 bonds per minute in the automated 2-wire tether production.|
|Henri Seppänen, Recearcher
University of Helsinki
University of Helsinki, Helsinki FIN-00014