Improved MK4 Fan Duct

This fan duct improves the air flow so the overhangs are better (up to 70º with very good quality, 3rd picture) I recommend to use Prusament PC Blend-Carbon Fiber or PA11-CF, because they are heat resistant and to reduce weight mainly, but other filaments may work just as well. I also recommend to use my improved fan door (to center better the fan duct): https://www.printables.com/model/621424-improved-mk4-fan-door. Caution : from version 7.0 sometimes it is necessary to reduce the fan speed a little! A reduction of 5-10% from your previous profile is usually sufficient. Warning 1 : If the fan test fails, please remove this fan duct and pass the test; then reinstall the fan duct. The original fan duct does not need to be installed to pass the test, it is simply left free. Warning 2 : it is recommended to be used together this model (or similar): https://www.printables.com/model/566871-mk4-hotend-fan-shield-eliminates-turbulence-drafts. It prevents air turbulences from extruder fan. Note: This fan duct can not be used with MK4S because its different fan duct new design. Printing Parameters: 5% infill 0.1 layer height 3 or more perimeters Changelog V3 (2023/10/21) Initial release (removed) V5 (2023/11/12) Better flow air. Divider to balance the flow air from left and right. Custom supports (can be removed, use split parts on PrusaSlicer). Optional: to be used with my improved fan door (https://www.printables.com/model/621424-improved-mk4-fan-door). Optional: .3mf file with multicolor version. V5 (2023/11/13) Solved small bug on the fan opening, please reprint again!! Removed V6 (2023/11/14) Same fan duct with 5% less weight 9.40g printed with PC Blend Carbon Fiber V6.1 (2023/11/18) Fan duct lowered 1.5mm to better reach nozzle tip (less air in nozzle block) V6.2 (2023/11/28) More separation from heatbed (0,5mm) Around another 5% less weight V6.3 (2023/11/30) Around another 3% less weight Slightly improved air flow Pass fan test! V6.3 Inserts (2023/12/01) Variant to use M3 thread inserts (M3x4.6x5.7mm) V6.4 (2023/12/26) I think now air flow is perfectly centered (please, see videos) https://www.facebook.com/groups/1910026672591728/?multi_permalinks=3492081117719601¬if_id=1703616893038356¬if_t=feedback_reaction_generic&ref=notif Can be used with thread inserts or without Pass the fan test V6.4 (2024/01/30) Removed all the previous versions V6.4 Wider (2024/03/18) I have added a wider (1mm) version, in some cases seems it is not well centered (due to the fan door, mine reduces this) V6.5 (2024/05/12) Increased air flow pressure Improved custom supports, easier to print V7.0 (2024/05/16) Even easier to print, it doesn't need supports Better air flow distribution Slightly increased air pressure As v6.5 can be used with or without threaded inserts Removed 6.4 versions V7.1 (2024/06/26) Added a small flange ("triangle") to prevent fan angling upwards, all merit to: jaxman smitty by this suggestion