National Institute of Standards and Technology,
Keywords: additive manufacturing, digital, voxel
Summary:In photopolymer additive manufacturing processes such as vat photopolymerization (VPP), high resolution 3D printing is enabled by the local photo-cure of liquid resin into solid polymer. This process depends heavily on the nature of the light source and the characteristics of the reacting resin. To push the limits of resolution and performance in VPP it is essential that both light source and reacting resin be well characterized and controlled at resolution better than the print resolution. Here we present high resolution light engine and resin/part characterization. For the light engine, we present the exemplary case of an LCD based printer and examine how variations in LED wavelength, local light intensity and pixel-scale divergence affect resultant parts. For parts/resin we present results using atomic force microscopy to map high-resolution local x-y-z variations in mechanical properties and conversion in both final parts and in-situ to the printing process. The local characterization of the printing process reveals new levels of control in the reaction, while also indicating potential pitfalls that hamper performance.