Prusa i3 MK3 part cooling fan LARGE.

thingiverse

This modification is designed for the Prusa MK3 with the 45-degree factory-recommended part cooling upgrade, specifically created to address the limitations of the basic part cooling duct on this model. Please note that this upgrade is not compatible with the newer MK3S version. The original part cooling duct was insufficient in providing adequate side and back-side cooling for PLA printed parts, resulting in subpar prints with excessive stringing and overhangs. However, the new design, optimized for PETG printing, offers a significant improvement by allowing for better air flow, effectively clearing all internal components while minimizing stringing and promoting visually appealing overhangs. A comparison image showcases the factory part cooling duct alongside the new design, clearly illustrating the increased airflow capacity of the upgraded component.