Electrochemical additive manufacturing of interdigitated structures using a multi-anode system with independently-controlled anodes

Interdigitated parts are used across a multitude of engineering applications. The overlapping, intertwined structures pose a challenge for fabrication using conventional additive manufacturing techniques, especially at small size scales. Electrochemical additive manufacturing (ECAM) has been shown to successfully create overhanging parts at the small scale without reliance on support structures. This study extends the ECAM capabilities into demonstration of the fabrication of interdigitated parts by the use of a multi-anode electrochemical additive manufacturing system. The ECAM process is operated by a tool head consisting of multiple anodes independently controlled by individual channels on an in-house-built multipotentiostatic system. Each anode is independently switched into active (anodic) or inactive (open-circuit) mode using a predefined, coded pattern controlling the custom electronics. While each tool is in anodic mode, its current contribution into the overall deposition process is tracked independently as well. Each independent tool can deposit material extending from regions deposited by itself or neighboring tools. The entire multi-head tool is controllably moved by a 3-axis translation system. An interdigitated comb geometry relevant to practical engineering applications is fabricated using this system. This geometry is built using a parallelized voxel-by-voxel tool path with characteristic electrode activation patterns at each position of the tool head. It was found that a purely closed-loop control with no time limit yielded a qualitatively better geometry than a control system with a 10-minute time limit applied. This study overall demonstrates the working principle of a multi-anode system and its ability to fabricate parts interdigitated structures. This study therefore advances the capabilities of ECAM as a valuable additive manufacturing process that can fabricate a variety of challenging parts for relevant engineering applications.