Modelling of Resonant Acoustic Mixing Parameters

Traditionally, multi-material blended components are mixed in

planetary mixers, cast to blocks/blanks, and undergo subtractive

machining to form shaped components. Composites such as

syntactics and highly filled resin based systems are blended in rotary

drums and other conventional blade based mixers over long periods

of time, decanted, moulded to blocks and again undergo subtractive

machining. These are both time consuming, wasteful and potentially

hazardous when working with energetically-sensitive materials.

Resonant Acoustic Mixing (RAM) is a novel powder/powder,

powder/fluid and fluid/fluid mixing technology that has the potential

to directly mix materials into the final net (or near net) component

shape without further processing, removing or significantly reducing

material waste, time and hazards. RAM is being trialled with a

defence contractor and is showing excellent results to-date. However,

modelling of this mixing technique is in its infancy and has not been

addressed and thus, cannot be said to be optimised. Numerous mixing

(intensity, time, pressure temperature), material (particle size, shape,

pre-blending, order of addition) and tooling (shape, composition,

mixing head space) parameters impact the efficiency of RAM and

thus if modelled would add significant value in optimising the mixing

process.

Modelling and/or trials would improve understanding of the

capability, both limitations and opportunities. A phase space of

mixing sweet-spots could be identified, further de-risking potential

processing operations by avoiding knife-edge scenarios. Once mixed,

the blend of powders still needs to be decanted to a mouldtool. This

presents a more controlled flowing environment but can lead to phase

separation layering and other forms of de mixing especially when considering particles of different size or density.