Wanhao i3 v2.1 stock 40mm fan rear mounted duct

thingiverse

WARNING! Recent testing has revealed a critical flaw! As I've mentioned earlier, using this duct at 100% fan can cause nozzle temperature drop by as much as 5 degrees Celsius. After conducting extensive research, I discovered that the actual temperature drop caused by the cooling flow is significantly higher, which results in a power consumption increase of up to 15 times! I've been printing with PLA, ABS, and PETG at nozzle temperatures ranging from 200 to 250 C and bed temperatures between 60 to 100 C for hours over the past month. At one point, my printer began to reboot continuously due to a partially molten plastic power connector on the Melzi board inside the control box. To rectify this issue, I removed the molten plastic and soldered the power wires directly to the power pins on the board, restoring my printer's functionality. In the meantime, I recommend adjusting the fan percentage or refraining from using this duct until I correct the flaw. This rear-mounted cooling duct is designed for the stock 40mm fan of Wanhao Duplicator i3 v2.1, attaching to one of the printing head's lower bearing plastic casing M4 holes with a 20mm M4 screw and conical cross-head. The fan is secured with stock M3 screws. The thread in the holes for the fan prints well enough with a 0.2mm layer, resulting in a rough surface that matches the stock screws. The bottom-most surface of this duct is designed to maintain a minimum distance of 1mm from the print bed at its lowest Z position. Appropriate supports have been designed for the fins, ensuring both the duct's and support geometries are centered at the Duplicator's print bed (X100 Y100), eliminating the need for manual positioning. The stock Wanhao cooling fan configuration blows air to the right of the nozzle instead of straight beneath it, obstructing the view of the print. This design is a result of multiple CFD simulations aimed at improving aerodynamic performance. Compared to the stock configuration, this design boasts improved: Flow (3.25 CFM versus 0.98 CFM in the stock configuration) due to a streamlined channel with minimal constriction and bigger exit cross-section area, along with curved fins on the walls that reduce residual air swirl. Flow direction: I've managed to straighten significantly the swirling flow of the fan, directing it directly at a small area right under and around the nozzle without causing any serious temperature drop during printing. The view is now easily accessible for visual inspection of the printing progress. It's worth noting that at 100% fan while printing first layers near the base plate or vast flat solid layers, the nozzle temperature may still drop by as much as 5 degrees due to flow being deflected from the surface. I've printed this duct from PLA and used it for printing with PLA without any temperature damage from the print bed (heated up to 70 degrees) or the nozzle (heated up to 205 degrees), even with the fan turned off. I hope this duct will help improve your prints' quality; designing it was an enjoyable experience, and seeing it perform as intended was rewarding. Printer Settings: Printer Brand: Wanhao Printer Model: Wanhao Duplicator i3 V2 Rafts: Yes Supports: Yes Resolution: 0.2mm Infill: 30% Notes: - 0.4mm extrusion width; - 10 top and bottom solid layers to improve fan mounting holes strength; - Max printing speed of 25 mm/s; - Custom supports used; - Printed from natural PLA at 205C nozzle, 70C bed, and 60% fan for layer 1; 195C nozzle and 100% fan for the rest of the print, with a 50C bed until layer 200; bed off for the remainder of the print. Update: To utilize my custom supports, ensure your slicer program allows objects to be placed at the same coordinates. Some slicers may still misplace supports (e.g., in Cura, uncheck "Ensure models are kept apart"). An all-in-one model of duct and supports has been added to ensure correct positioning in all slicers.