Anet A8 Extruder Fan Modification (remix with switch)

thingiverse

UPDATE: This isn't ready for prime time yet!\r\n\r\nThe fan duct creates uneven cooling, depending on its orientation. One-quarter of the part performs well, but the remaining three-quarters don't fare as well. The duct only allows airflow from one direction and can't cover the regions that need cooling, regardless of orientation. I've been tweaking it and achieving better results, but I'm not there yet. Thermal issues, particularly related to print speed, are a major headache. Printing at 35 mm/s for the outer wall works fine, but that's no way to live your life.\r\n\r\nUpdate2: It wasn't a thermal issue after all. The ducts (I designed 12 in total, with three versions and four different dimensions each) weren't the problem. The main issue was my own foolishness. I tried to adjust the slicer settings to get around the actual cause (next paragraph), but these settings remained and reproduced the error. Outer wall line width set lower than nozzle diameter by 0.05mm, and at some point, I also set the "Outer Wall Inset" (Cura) to 0.1mm. This adds up to a total of 0.075mm difference from nozzle size of 0.4mm.\r\n\r\nThe reason for messing around was physical. The extruder motor couldn't push enough filament into the hotend due to modifications. This was because the counterpart, pressing the filament thread against the extruder motor, didn't have enough force, and while the extruder was spinning, no filament was pushed down, especially at higher rates.\r\nSo I rebuilt everything back to its original state, except for the switch on the fan. That's a lot easier to fix - just cut either wire and solder in a switch.\r\n\r\nTroubleshooting/how to avoid this/catch it early on:\r\n- Use different slicers (I mainly use Cura, Slic3r on Linux, but didn't)\r\n- Don't make too many changes at once (I changed the duct, extruder cooling, filament brand, slicer settings, and my hairstyle; either you can see the cause or you have to do test series)\r\n- Don't change things while drunk and then forget about it\r\n- Make notes and backups of what settings worked to spot physical issues\r\n\r\n\r\n[S]This is a remix of hadoko's fan mod (https://www.thingiverse.com/thing:2290361).\r\n\r\nThe main difference is that I added a switch, the fan is positioned differently, and the attachment of the heatsink was changed.\r\n\r\n\r\n\r\nI broke some blades on my extrusion fan and it became incredibly loud. I found hadoko's mod and adjusted it for my needs.\r\nThe original construction of the fan and heatsink is very cost-efficient. Very few parts, directly screwed to the extrusion motor. Each time you want to access it, you need to disassemble that whole thing. This mod is a way to make changing filament very easy.\r\n\r\nAt last, I plan on designing a mechanism that allows the printer to use the fan switch by driving to certain coordinates. Does anyone know how to get to negative positions? I mean between endstop and bed.[/S]