This is a remix of an existing Core One exhaust vent flap design (found here), using a dryer-style gravity flap mechanism to help retain chamber heat when the exhaust fans are off.
The flaps pivot open when airflow from the exhaust fans is present, and automatically close under gravity when the fans stop. When closed, they block the exhaust outlets to reduce passive heat loss. When open, they allow exhaust airflow with minimal restriction.
This helps maintain higher chamber temperatures for materials like ABS, ASA, and PC, while preserving normal exhaust behavior for PLA and other low-temperature filaments.
Print the frame and four flaps.
Tilt the Frame Back. (So the slots are facing up.)
Set the flaps into the frame (They will sit loosely in place, so they can swivel easily.)
Ensure each flap spins freely by rotating the housing with them installed.
(They should move freely with gravity, sanding or lubrication MAY be required.)
Mount the frame over the rear exhaust outlets w/ M3x8 Screws.
4x M3x8 Screws (Longer can work): https://amzn.to/4sEeI1g
PETG/ABS/ASA Filament: https://mrly.link/prusament
Prusa Core ONE: https://mrly.link/coreone
Vent Flap Frame CAD Fusion
Vent Flap Frame CAD STEP
Exhaust Vent Frame STL
Exhaust Vent Flap STL
0.2 mm Layer Height
3 Perimeters
20%+ Infill
NO Supports Required
PETG or Higher Temp Materials (Slick filaments pivot nicely I've noticed.)
This mod is fully passive and does not alter firmware or fan control. It simply reduces heat loss when the exhaust fans are inactive.
The author remixed this model.
Remixed with the goal of closing up the air gaps around the fan outlets more.