Acoustic liquid manipulation

Acoustic Liquid Manipulation (ALM) is a term coined to describe the use of non-linear acoustics to move liquid, manipulate liquid surfaces, and propel buoyant objects. It differs from acoustic levitation because it does not rely on standing waves but instead uses focused directed beams operating at RF frequencies, employs burst modulation and transmits through liquids. Transducers with simple focusing lenses were employed initially but now the emphasis is on acoustic phased arrays. Applications both real and contemplated involve the acoustic dispensing of droplets from needles, ejection of droplets from free surface pools, and acoustic manipulation of free surfaces, bubbles and objects. NASA is evaluating these techniques for a variety of multiphase fluid systems including space experiments and systems for the Space Station. Meanwhile, ground manufacturing applications range from PC board electronics to micro-electronic and micro-machine scale devices. ALM is already being developed to reduce or eliminate masks in plating and etching operations, which, in turn, reduces waste products.