3D Printed " Perfect Particles"

Author Last Name: 
Karen Hapgood, Negin Amini, Jun Zhang
Report Type: 
Research Area: 
Particle Formation
Publication Year: 
Publication Month: 

Executive Summary
Accurate and systematic validation of particle systems with a simulated model has not been possible
due to lack of suitable test particles. To date, the cumbersome approach has been to individually
measure the relevant properties of existing non-identical particles. These parameters are then
entered into a computer for imprecise estimates of the model simulations, then compared against the
actual experimental measurements. The two key drawbacks of the current approach are 1) the
inability to capture the true complexity of the agglomerate structures in simulations and 2) the
destructive nature of the experimental tests i.e. breakage, dissolution etc., which would eliminate the
possibility of reproducing the data under the same conditions. Therefore, experimental data produced
from a ‘single’ individual agglomerate can never be replicated.
3D printing technology allows mass fabrication of identical agglomerates that can be tested repeatedly
under the same condition/orientation and then repeated for various other conditions and
orientations. To date, this has not been possible via experimental agglomeration production
techniques. In the previous IFPRI project, identical copies of agglomerates were designed and printed
and the breakage behaviour was compared with a DEM simulation of an agglomerate with an identical
structure. For the first time, experimental tests on “perfect” particles with tuneable properties were
successfully conducted and the results were highly reproducible.
The new IFPRI project contains three sub projects which focus on agglomerate breakage, agglomerate
disintegration and powder flow and segregation using the newly developed approach. The published
work from this project would enable the particle technology worldwide community to take up the
ideas and implement them broadly. In year one of this project, quasi-static compression tests of
identical spherical agglomerates 3D printed in colour were carried out to investigate the distribution
of strength behaviour at different strain rates. A Stratasys Object 500 Connex 3 was used to print the
agglomerates in colour. By dividing the agglomerate into coloured sections, it will be possible to track
orientation, individual particles and observe the breakage behaviour with much more accuracy and in
more detail. Soft, rigid and a hybrid mixture of both soft and rigid materials were used for the
agglomerate bonds to determine the optimum bond material to prevent individual particle breakage,
something which had not been previously observed. X-ray tomography of the agglomerate was carried
out for the first time which showed the layer by layer detail of the 3D printing process. A description
of this work is included in this report, and the first “proof of principle” paper will be ready for
publication in Q1 2019. This report summarises the progress to date and the remaining work for years
2 and 3.