Ultrasonic particle levitation - could it be used for 3d printing?

I found a video demonstration of small particles levitating in air held and manipulated by ultrasonic field.

My first thought was: this could be used in 3d printing!

Particles could be manipulated and held in shape by this ultrasound technology and then melted together by laser or ultrasound energy itself. I know it is far fetched theory ... but somehow I think it could be done ...

Ultrasonic technology is already used in high-end metal 3d printing by Fabrisonic:

http://diy3dprinting.blogspot.com/2013/07/ultrasonic-metal-3d-printing.html

And similar technology is also used to weld plastic:

http://diy3dprinting.blogspot.com/2012/12/diy-ultrasonic-plastic-welding.html

So, all these technologies could be merged together, why not?

Video of ultrasonic particle levitation:


Video description:

The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes and, so far, this method has been used to levitate lightweight particles, small creatures, and water droplets.
The acoustic axis of the ultrasound beam in these previous studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that various materials could be manipulated by our proposed method.

Source:

http://96ochiai.ws/3DOFacoustic

Experiment was done and domnstrated by Yoichi Ochiai, Takayuki Hoshi and Jun Rekimoto ( University of Tokyo, Nagoya Institute of Technology, University of Tokyo and Sony CSL ).