Title: Role of substrate stiffness in ultrasonic consolidation

Authors: Chris J. Robinson; G.D. Janaki Ram; Brent E. Stucker

Addresses: U.S. Naval Air Warfare Center Weapons Division, China Lake, CA 93555, USA ' Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036, Tamil Nadu, India ' Department of Industrial Engineering, J B Speed 201, University of Louisville, Louisville, KY 40292, USA

Abstract: In ultrasonic consolidation (UC), if the substrate is not stiff enough, no friction can occur between the foil being deposited and the substrate, which is essential for achieving bonding. The requirement that the substrate be stiff enough to resist deflection can impose certain geometrical restrictions on the process. Further, build orientation can have a strong influence on the process. In the current work, the role of substrate stiffness in UC was investigated. Freestanding rectangular ribs of three different widths in aluminium alloy AA 3003 were built in three different orientations such that the long axis of the rib is parallel, perpendicular and at 45q to the direction of sonotrode vibration. Studies show that freestanding ribs can only be built to a modest height-to-width ratio of around 1. Build failures occur not only because the substrate stiffness reduces with build height, but also due to a number of machining-related problems that accumulate as more and more layers are added. The results show that building freestanding rectangular ribs is best done by orienting the long axis of the rib at 45q to the direction of sonotrode vibration.

Keywords: rapid manufacturing; ultrasonic consolidation; ultrasonic welding; substrate stiffness; aluminium alloys.

DOI: 10.1504/IJRAPIDM.2011.043457

International Journal of Rapid Manufacturing, 2011 Vol.2 No.3, pp.162 - 177

Published online: 18 Feb 2015 *

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