Ultrasonic consolidation

Ultrasonic Consolidation (UC), sometimes referred to as Ultrasonic Additive Manufacturing (UAM), is an additive manufacturing technique based on the ultrasonic welding of metal foils and CNC contour milling.^[1] High-frequency (typically 20,000 hertz) ultrasonic vibrations are locally applied to metal foil materials, held together under pressure, to create a solid-state weld. CNC contour milling is then used to create the required shape for the given layer. This process is then repeated until a solid component has been created or a feature repaired/added to a component. UC has the ability to join dissimilar metal materials^[2] of different thicknesses and allows the embedment of fibre materials at relatively low temperature, (typically less than 50% of the metal matrix melting temperature), and pressure into solid metal matrices.^[3][4]

History

The Ultrasonic Consolidation process was invented and patented^[5] by Dawn White. In 1999, White founded Solidica Inc.^[6] which is the commercial owner and provider of the UC technology.^[7] The commercial equipment for UC is called the Form-ation machine.

Process

As with most other additive manufacturing processes UC creates objects directly from a CAD model of the required object. The file is then "sliced" into layers which results in the production of a .STL file that can be used by the UC machine to build the required object, layer by layer.

A schematic of the Ultrasonic Consolidation process.

The general manufacturing process is:^[8]

• A base plate is placed onto the machine anvil and fixed into place.
• Metal foil is then drawn under the sonotrode, which applies pressure through a normal force and the ultrasonic oscillations, and bonded to the plate.
• This process is then repeated until the required area has been covered in ultrasonically consolidated material.
• A CNC mill is then used to trim the excess foil from the component and achieve the required geometry.
• The deposit and trim cycle is repeated until a specified height is reached, (typically 3–6 mm).
• At this height a smaller finishing mill is used to create the required tolerance and surface finish of the part.
• The deposit, trim and finish cycle continues until the finished object has been manufactured; at which point it is taken off the anvil and the finished article is removed from the base plate.

References

1. ↑ Advanced Materials and Processes, Ultrasonic Consolidation of Aluminum Tooling, D.R. White, Vol. 161, 2003, pp. 64–65
2. ↑ Rapid Prototyping Journal, Use of Ultrasonic Consolidation for Fabrication of Multi-Material Structures, G.D. Janaki Ram; C. Robinson; Y. Yang; B.E. Stucker, Vol. 13, No. 4, 2007, pp. 226–235
3. ↑ Composite Structures, Ultrasonic Consolidation for Embedding SMA Fibres within Aluminium Matrices, C.Y. Kong; R.C. Soar; P.M. Dickens, Vol. 66, No. 1–4, 2004, pp. 421–427
4. ↑ Journal of Engineering Materials and Technology, Characterization of Process for Embedding SiC Fibers in Al 6061 O Matrix Through Ultrasonic Consolidation, D. Li; R.C. Soar, Vol. 131, No. 2, 2009, pp. 021016-1 to 021016-6
5. ↑ http://www.freepatentsonline.com/6519500.html
6. ↑ http://www.solidica.com
7. ↑ http://home.att.net/~castleisland/tl_221b.htm
8. ↑ http://www.solidica.com/systems.advanced.html