Optimization of Geometric Nozzle Parameters for Chocolate-Based 3D Printing
Our team optimizes the nozzle geometry for popular commercial chocolate 3D printers (i.e. Cocoa Press 1 3D Printer) to improve structural performance and aesthetics of chocolate. The Cocoa Press 3D-Printer is a standard FDM (Fused Deposition Model) 3D-printer, integrating a heated nozzle to layer cross-sections of liquid filament and create a three-dimensional design. Given the novel method for pre-heating the chocolate in a reservoir prior to deposition, these designs bypass typical tempering recommendations for commercial chocolate figures. This limits structural strength through reduced internal crystalline structures formed by sugar, forming a softer and more deformed final product. Our team analyzes methods for optimizing the Cocoa Press 1 3D-Printer nozzle geometry to refine outlet temperature and tempering across different input parameters (feed rate, cocoa percentage, etc.). This is accomplished by iterating across several nozzle diameters and lengths to isolate the temperature profile of liquid chocolate fed through a commercial nozzle. Through finite-element analysis (FEA) in COMSOL, none of the tested nozzle geometries were found to achieve effective chocolate tempering under the simulated operating conditions. Across all configurations, outlet temperatures remained nearly constant, indicating insufficient thermal regulation within the nozzle to induce the phase transformations required for proper tempering. While variations in nozzle diameter and length influenced flow behavior, particularly peak velocity and flow development, neither produced meaningful changes in outlet temperature from the baseline of 322 K. As a result, the Cocoa Press system in its current form does not achieve tempering through geometric modification alone. These findings suggest that additional process controls, such as active cooling or upstream tempering mechanisms, are necessary to achieve structurally stable and properly crystallized chocolate during extrusion.