"Mistral" Extruder Cooling Duct for the Anet A8 Printer

thingiverse

I've been designing and building all sorts of cooling ducts for the past two months, as I wasn't satisfied with what was out there. Even popular round ducted coolers don't do a good job of directly cooling the filament while keeping the heat block hot. Many online designs are too clunky, too heavy, or are poorly thought out. With new firmware like Marlin incorporating thermal protection mechanisms, it's now more important than ever to have a design that won't trigger false alarms. This is especially true when the cooling duct blows air directly on the heat block rather than the filament. Design objectives: * Blow high-volume air on the filament just beyond the nozzle. * Avoid getting cooling air on the nozzle/heat block as much as possible. * Create a design that doesn't obstruct the view surrounding the nozzle. * Make it easy to access the nozzle with tweezers for removing filament. * Design it so it's easy to print. * Keep it as light as possible to avoid high mass on the extruder. It weighs 2.8 grams. At the end of the day, I've found that this design outperforms anything I'd tested before. Attention: This cooling duct is designed for use with standard unmodified A8 printers. It's recommended to print the cooler in ABS or PETG as these filaments are more heat-resistant. However, I've printed mine in PLA without any issues. When printing ABS or high-temperature filaments, simply remove the cooler. You usually don't print with the fan on for high-temperature filaments. With this cooler, you may need to reduce airflow during some prints! Sometimes I have to print at 75% or less, where previously airflow was set to 100%. I want to thank Jan Hedström for testing this cooling duct and confirming its effectiveness. Also, thanks for the suggestion of giving it a cool name - "Mistral"! Please let me know if you encounter any issues with the design so I can improve it if necessary. Also, please post a picture with comments if you've made one. Thanks, Leo If you're using SkyNet3D, you can use a function to calibrate your extruder nozzle via "PID Autotuning". You'll already find PID values in the firmware; however, it's a good idea to set them according to your surroundings. This is how to calibrate the hotend: First, we need to get the PID values from the hotend. The values are read in 8 cycles using the following code: M106 M303 E-0 S210 C8 Code description: * M106 runs the nozzle at 100% * M303 starts PID autotuning * E-0 selects the first hotend * S210 sets the extruder temperature. We chose 210°C in this example. * C8 denotes the number of cycles. In this example, 8 After the 8 cycles are complete, you'll see something like this: Kp: 14.68 Ki: 0.70 Kd: 76.59 Now, you'll need to save the values to the printer's eeprom: M301 P14.68 I0.70 D76.59 M500 Code description: * M301 temporarily sets the PID values * P = Kp * I = Ki * D = Kd * M500 will save the temporary PID values to eeprom. More information can be found here: http://reprap.org/wiki/PID_Tuning Update 15.2.2017: I've added a thicker-walled (1.2mm) version 1.0a to the files section. In my opinion, the standard (0.8mm) thick version 1.0 is best used; however, some users have asked for a "beefier" cooling duct. Update 19.2.2017: I've uploaded a new version, "Mistral 2", as an alternative depending on your needs: http://www.thingiverse.com/thing:2121279 Print Settings: * Printer: + Anet A8 * Rafts: + No * Supports: + Yes * Resolution: + 0.2 * Infill: + 100% * Notes: + Top and bottom layer height should be set to 0.8mm. + Only use supports for portions touching the bed!