Production by 3D Printing of Injection Molding Inserts with Heat Dissipation Properties

This thesis explores the potential of pellet-based fused granular fabrication (FGF) for the production of injection molding inserts, focusing on the transition from filament-based fused filament fabrication (FFF) systems to pellet-fed 3D printing with the Piocreat G5 PRO. Unlike conventional filament approaches, FGF eliminates the intermediate extrusion step and allows the direct use of compounded or recycled feedstocks, offering significant reductions in cost, lead time, and material waste. These advantages make pellet extrusion particularly attractive for rapid tooling, prototyping, and small-batch manufacturing where flexibility and speed are critical. The research establishes a complete FGF-based workflow for producing polymer–metal composite inserts, validating the capability of the G5 PRO system to process both commercial polymers in pelletized form and newly developed materials. In particular, PLA–Copper composites with filler loadings of 60, 80, and 90 wt% were formulated to address the key limitation of polymer tooling: low thermal conductivity. These composites were characterized, fabricated into inserts, and benchmarked against commercial Copper Filament, Carbon PA, HTPLA, and a steel reference. Experimental injection molding trials, repeated over ten cycles for each insert, highlighted the dual role of copper: higher filler contents enhanced heat dissipation and shortened cooling times, but at the expense of mechanical toughness, introducing brittleness that could reduce tool durability. Among the tested materials, PLA–Copper 90% and the commercial Copper Filament achieved the highest thermal performance, delivering faster cooling and superior part replication that closely approached the response of steel inserts. However, PLA–Copper 80% proved to be the most balanced solution, offering strong thermal conductivity together with higher structural stability and durability under molding conditions. By contrast, PLA–Copper 60% showed only marginal improvements over neat PLA. Moldex3D simulations were conducted in parallel to the experiments and confirmed the observed trends, demonstrating consistency between predicted thermal behavior and real molding performance. This validation underlines the reliability of simulation-based process optimization for polymer–metal composites in rapid tooling applications. Overall, the research demonstrates that FGF, combined with tailored polymer–metal composites, can extend the practical use of additively manufactured inserts beyond prototyping. While polymer inserts cannot fully replace steel in high-volume production, their performance is sufficiently close for low-volume, pilot-scale, or specialized applications. By advancing material formulations, optimizing process parameters, and exploring hybrid solutions, pellet-based 3D printing emerges as a viable, sustainable, and cost-effective alternative to filament-based approaches for rapid tooling in injection molding.