Achievement of maximum resolution is a crucial precursor to obtain 3D structural details suited for microstereolithographic applications. Here, we present a family of open-source stereolithography printing materials optimized for maximum resolution and surface quality. To illustrate the potential of our recently developed multi-material digital light processing (DLP)-based 3D printing system to produce high-resolution, high-quality microarchitectures, we exploit a wide variety of resin formulations to determine optical formulation to yield maximum printing resolution and surface quality for a tailorable range of thermomechanical properties. The observed changes are explained in key terms of the relationship between the optical photofield and reaction kinetics.
We developed and fabricated a novel DLP-based microstereolithography voxel 3D printing system capable of producing high-resolution hybrid components made of multiple materials in a fully automated and efficient manner for increased speeds with a minimal-waste material exchange mechanism involving an air jet to rid the substrate of residual liquid resin post each exposure significantly reducing the time to print. We demonstrate a variety of microarchitectures of differing voxel geometries exploiting the above study conducted on resin formulations enabling rapid voxel assembly with tailorable thermomechanical properties catering to different applications.
The advent of new 3D printing techniques has provided sizeable implications in a breadth of fields including tissue engineering, soft robotics, nano-devices, metamaterials, and many others. Further improvement in the fidelity of fabrication via 3D printing requires the creation of optical surfaces, a core challenge that is hindered by laying artifacts; i.e. stairstepping phenomenon, inherent to layer-by-layer processes that encompasses most 3D printing techniques. Digital light processing-based systems such as projection microstereolithography (PµSL), which employs a digital micromirror device (DMD) as a dynamic photomask to precisely form solid structures, fails to fabricate smooth surfaces because of non-uniformities in light intensity across the field of view. This is brought about by dead space in the matrix of discrete digital micromirrors. This study aims to integrate optical oscillation into the light engine modulator of PµSL to inherently eliminate surface roughness as caused by discretization of images into a pixel array. Our new low-cost, oscillation-assisted system, introduced alongside a family of custom-formulated photopolymers devised specifically for optical surfaces from above study, affords rapid, high-resolution, one-step direct writing of arrays consisting of symmetrical and asymmetrical microlenses with sub-wavelength surface roughnesses without any required post-processing.