Extractor cone

A flange for connecting a 120mm fan to an enclosure for fume extraction. Outer dimensions of top rectangle: 220x180mm. There is a protrusion on the bottom meant to connect the part to a 1/2" / 12.7mm rod, to use without attaching to an enclosure. The structure is meant to be 3D printed, so I limited overhangs to 45deg and split the model to create shaped spacers for screws.