Vent Cover/Filter?

thingiverse

It's a vent cover design, featuring two models. I successfully printed both models without top or bottom solid layers, using triangles as the fill pattern and an infill level of approximately 30% to 40%. The version with circular openings can be printed solid for added strength. This particular design was created specifically for a narrow bathroom vent, so it's likely you'll need to adjust the scale to match your own vents' specifications. UPDATE October 26, 2018 Research has shown that air flow is significantly reduced when printing at 40% infill. To minimize this loss of airflow, consider using a lower infill percentage, as seen in the second model with no openings.