Parameter Study of Self Assembly of Hollow Particles for Simultaneous 3D Printing
Discipline: Technology and Engineering
Subcategory: civil/mechanical/industrial
Session: 2
Room: 3 - Hanover C
Marcelo Farfan - University of South Florida
Co-Author(s): Zijian Weng, University of South Florida, FL Richard Murphy, University of South Florida, FL Umniyah Irfan Malik, University of South Florida, FL
There have been several studies done with particle charge in an aeolian electric field. This electric field is produced when particles blown in the wind begin rubbing against each other, producing charge with their adjacent particles. It is a complex system that can only be optimized through monitoring of humidity in the air, particle size, mass and dielectric property of the material. Humidity in the air is the most critical factor, the layer of moisture between particles is used to transfer ions. However, if the air is too damped, then the ions are neutralized. Optimizing these conditions allows these particles to act as magnets to each other and have the potential for “bottom-up” assembly.
Our research wishes to use electric fields in 3D printing manufacturing. Our findings have found that an external electric field can amplify the charge transfer between particles, and have produced several 3D columns built all at once. This set-up uses a parallel plate capacitor set-up with the bottom plate grounded and top polarized by the conductor. The location of where these particles are built can be controlled by using an insulating top plate with a conductive pattern. Under the conductive pattern, the powder is able to enter a cycle of oscillation, allowing for enough collisions for ion transfer to occur with the adjacent particles. However, we hypothesize that the effects of aeolian electric fields are still relevant. A parameter study was conducted with the use of 3M hollow glassbubbles. They are excellent for figuring out what parameters lead to optimization, as they come in several sizes while maintaining similar density to each other and vice versa. Allowing for a change in the physical parameter while avoiding dopants. By changing a single element of the set-up, it is possible to figure out what optimizes self-assembly. The parameter study involved the changing of diameter while maintaining the same range density, different densities at the same diameter range, how separating of the plates affects the field, the volume of powder placed in the chamber, and how humidity will affect same-density glass bubbles at different particle sizes. Our findings show that a relative humidity under 50% produces columns without the need a relatively high electric field strength, and going between 20-32 um diameter particles seem to require the most electric field strength to be able to assemble. It tends to be easier to assemble at lower heights and with more powder in the chamber. Future research will use the information gained from this parameter study to create high-resolution 3D arrays, with the hope of eventually reaching 100 um thin pillars.
Funder Acknowledgement(s): The Florida Georgia Louis Stokes for Alliance Minority Participation (FGLSAMP) Bridge to the Doctorate
Faculty Advisor: David Murphy, davidmurphy@usf.edu
Role: Parameter study, and literature review on aeolian electric fields.