Development of Air and Water Based Fluidized Beds for Open Pyrojet : Rotoforge.
Channel: Rotoforge
Date: 03/10/2022

This last couple of weeks has been spent developing fluidized bed feeding mechanisms for the Rotoforge prototype. 
We needed a way to coaxially feed material into the rotating tool face, so we tried low pressure air and a falcon tube gaseous fluidized bed to carry aluminum metal powder under the tool head to some encouraging if dangerous results.
This prompted us to consider safer options that would not require a containment. Such as wet fluidized bed in water. Underwater friction stir deposition and underwater friction stir welding have already been explored to some extend in the literature. Additionally, some exciting possibilities regarding cold sintering may exist.... only time and further experiments can tell! 
Still, getting a reliable coaxially feed system has led us to find other solutions to bypass the centrifugation problem of having a liquid in contact with the inside of a rotating shaft...we think we have found a solution to push us forward to a safe, easy to use, reliable and highly flexible, material agnostic 3D printer for heterogeneous metals, plastics and ceramics of high quality, on the home desktop. 

Paper on cold sintering and exclusion of liquid phase from solid phase under pressure:
https://www.researchgate.net/publication/337441883_A_theoretical_analysis_of_cold_sintering

Underwater additive friction stir deposition paper of interest:
https://www.sciencedirect.com/science/article/pii/S0264127522007705

Under water friction stir welding paper of interest:
https://link.springer.com/article/10.1007/s11661-012-1314-2

Under water friction stir welding simulations by others:
https://www.sciencedirect.com/science/article/pii/S223878541931957X


Our project documentation website in need of updates soon:
https://www.rotoforge.com/introduction/

Rotoforge  discord where we share ideas and talk shop:
If you would like to join the quest!
https://discord.gg/RNmgxyVBe9

If you want to follow our implementation details as they happen:
https://dailyrotoforge.blogspot.com/

if you want to build on our last working version:
https://github.com/Sindry-Manufacturing/rotoforge

if you want to build on a simpler process and explore parameters as cheaply and quickly as possible:
https://zenodo.org/records/10391990