Light Directed Electrophoretic Deposition for Additive Manufacturing: Spatially Localized Deposition Control with Photoconductive Counter Electrodes

Abstract

Electrophoretic deposition (EPD) has traditionally been viewed as a thin film deposition technique for coating conductive surfaces. Recently, there have been reports of producing functional parts with EPD to near net shape, often containing gradients in material properties normal to the conductive deposition surface. By using reconfigurable electrode systems, a few researchers have gone beyond purely out-of-plane gradients and demonstrated gradients in material properties in the plane of the deposition electrode, a necessary condition for 3D additive manufacturing. In this work, we build upon a previously published technique called light directed electrophoretic deposition (LD-EPD) in which the deposition electrode is photoconductive and can be activated with light, leading to a patterned deposit. Here, we demonstrate that the LD-EPD technique can also lead to patterned deposits on any conductive surface by utilizing the photoconductive electrode as the counter electrode. This eliminates several issues with standard LD-EPD by allowing the potentially expensive photoconductive electrode to be reused, as well as mitigates post-processing material compatibility issues by allowing deposition on any conductive surface. We also detail the results of a finite element simulation of the deposition process in LD-EPD systems that captures key features seen experimentally in the final deposit.