While over the last century EPD has been used to apply coatings to entire automotive and aerospace components, a new paper suggests that the coating technique could be made to dynamically apply finishes to specifically chosen regions.
According to Andrew Pascall, lead author and Research Engineer at Lawrence Livermore National Laboratory (LLNL), "We have presented a novel electrophoretic deposition technique based on using light to pattern materials on a photoconductive layer. This represents a large step in advancing electrophoretic deposition as a method of fabricating complex 3D patterned composites."
In their new paper, LLNL scientists detail how photoconductive electrodes and DC electrical fields can be used to tailor where a surface finish is placed. Called Light-Directed Electrophoretic Deposition (LDEPD), the new technique has been used to create a finely tuned alumina ceramic-tungsten nanoparticle composite that conformed to a pre-determined geometry.
“Initially, the tungsten nanoparticles were deposited across the photoconductive surface, then illuminated through a laser cut aluminum mask,” reads a LLNL statement. “A different shaped mask was then substituted along with the new material, to deposit the ceramic material.”
While an aluminum mask was used in trials, researchers believe that a digitally projected mask, like those used in DLP TVs, will soon replace its physical counterpart and bring automation to the LDEPD process.
In the end, a fully automated LDEPD process could lead to a new class of AM machines capable of processing unique composites into functional components. With one of the widest material latitudes of any AM process, a mature LDEPD technique would be an excellent addition to additive manufacturing’s arsenal.
Image Courtesy of Lawrence Livermore National Laboratory