Researchers Use Light to Refine EPD Processes
15 April 2014
Lawrence Livermore National Laboratory has found a promising substitute for electrophoretic deposition (EPD), a method long used for coating material on product assembly lines especially in the car manufacturing industry, after creating a novel technique called light-directed electrophoretic deposition, the lab says on its website.
Researchers who worked on development of the new method are hopeful that it represents a huge leap forward in the fabrication of complex 3D-patterned composites.
The main advantage of the technique is that, unlike EPD, which can only deposit material across the entire surface rather than in specific, pre-determined locations, it can dynamically pattern the surface material thanks to the photoconductive electrodes and DC electrical fields it uses. With the novel method, it is possible to deposit material in areas where the light interacts with the photoconductor's surface and thus create patterned 3D multi-material items over large areas with good resolution.
The scientists employed the technique to create an alumina ceramic-tungsten nanoparticle composite. The tungsten nanoparticles were first deposited across the photoconductive surface and then targeted with a laser-cut aluminum mask. The researchers then used another mask with a different shape to enable the buildup of the ceramic material. The scientists say that in the future the aluminum mask will be replaced by a digitally-projected mask to make the deposition process fully automated.
The research has been detailed in a report titled Light-Directed Electrophoretic Deposition: A New Additive Manufacturing Technique for Arbitrarily Patterned 3D Composites."