Functional texturing of micron-scale surfaces by electroforming and additive manufacturing

Abstract

The combination of additive manufacturing (AM) technologies, such as mask stereolithography (MSLA), with the electroforming process allows the creation of tools for surface texturing at the micrometric scale using the spark erosion die machining (SEDM) process. The objective of the present study is to generate functional textures on surfaces using different geometric patterns in both low and high relief, although the focus of the present study will be on low relief texturing due to its greater complexity. The design of the laboratory equipment facilitates the manufacture of these textured metal shells, thereby enabling the control of key process variables. This work quantifies how anode-cathode distance (ACD) and electrolyte recirculation govern deposited mass and thickness uniformity, and demonstrates micro-texture transfer. Two studies were conducted. First, ACD was screened at 60/120/180 mm under a stepped-current program. Second, recirculation mode (none, intermittent 5-on/10-off, continuous) and pump power (60-90%) were varied in a constrained design, with ACD fixed at 60 mm. Results show a clear distance effect: an ACD of similar to 60 mm delivered the highest mass gain (approximate to 0.45 g in 60 min at 500 mA), roughly doubling that at 120-180 mm. Under recirculation, total mass remained comparable, but homogeneity improved with moderate continuous flow (60% power), whereas excessive flow promoted edge stratification and occasional underfill. Therefore, for this application, the selection of the aforementioned parameters shows a practical window for producing uniform and robust electroformed tools for functional texturing of microscale surfaces.