Fabrication of functional surfaces using layer height method in material extrusion type 3D printing

Various layer stacking methods have been employed in material extrusion type three-dimensional (3D) printing to utilize their potential for addressing the inherent technological limitation of reduced surface quality due to layer stacking. The process involved fabricating a material extrusion type 3D printed mold using diverse layer height-changing methods and subsequently replicating the surface pattern with the polymer. This approach is called the layer height method (LHM) and comprises three distinct variations. The first method involves altering the height of the individual layers to generate diverse surface morphologies and, consequently, varying the range of water contact angles. The second method focuses on rapid layer height changes to facilitate liquid deposition within regions with low contact angles. Finally, a layer height gradient was systematically established within the mold, resulting in a wettability gradient surface capable of controlling the movement of water droplets across the surface. The performance of these functional surfaces was successfully validated using various experimental methods. This study introduces a manufacturing technique based on changing layer heights within the framework of material extrusion-type 3D printing technology. A wide range of intricate and diverse functional surfaces can be produced by extending the manufacturing method proposed in this study to 3D printing technologies beyond the scope of material extrusion type 3D printing.