Easy exchange filament extruder

thingiverse

For a new printer I required an extruder setup. I print with ABS frequently so this one is designed specifically for that (though it also works with other filaments). With ABS printing you do not want airflow passing over the printed parts. Therefore, the air is drawn in from above and passed through to the Hot-end before being expelled at the top. The same airflow configuration is also used for the motor. This way, the printed part remains unaffected by these two fans. For the dimensions of these snail house fans, please refer to the picture. I also wanted an extruder where changing filament is straightforward. On most extruders, you cannot see the filament wire and this can make it challenging to change the filament. If you run out of filament during a print, you are in big trouble. Therefore, I designed this one so that you can always see the filament wire. Because I have three different sizes of Filament (1.75mm, 2.85mm & 3mm) this extruder can accommodate them all. To do this, I created an exchangeable filament wire guide. For the 1.75 mm filament, I also need to insert a Teflon tube because the hot-end is designed for 3mm wire (I highly recommend using it because the filament slides in much smoother). The filament guide is adjustable so you can guide your filament perfectly. In the photos, this guide is not visible because that is still a prototype model. On that version, the 3mm guide is fixed to the body. Not very smart, because once it's broken, like I did, you cannot adjust anything anymore. As a loose part, you can simply reprint it again. The guide is attached using a washer, M3 nut and 10mm bolt. The little filament driver (11mm diameter) is mounted on an M8x50mm bolt that I happened to have lying around. On the lathe, I turned down the end of this M8 bolt to 5mm so the driver can be attached to it. See pictures. The Hot-end is a cheap Chinese one that I do not even know the name of, but it works very well. For the dimensions of this Hot-end, please refer to the pictures. The stepper motor is a Nema 17 x 47mm. I recommend using a strong motor for this if you want to use 2.85 & 3mm filament wire. In the picture, you see a 42BYGHW811, but I am currently using an SL42S247A (a bit more torque). As a driver, I still use an A9844 with heavy cooling and a heat sink. For the main body, I had to add support material. See the picture for how to remove the support material. All other parts can be printed without support. I have printed all the parts in PET-G at 0.2mm resolution and a 0.4 nozzle. You will also need: 3x bearing 608z 1x 11mm driver 1X M8 x 50mm bolt or something similar 1x hot-end 2x snail house fan 1X spring (optional, depending on filament material) 1X nema 17 stepper 1x kapton tape 12X M3 nut 4X M3 x6mm bolt 9X M3 x 10 mm bolt 3X M3 x20mm bolt 9X M3 washer (optional) 1X M3 big washer for filament guide 8X M4 nut 5X M4 x20mm bolt 1X M4 x40mm bolt 5X M4 washer (optional) After assembly, it is wise to apply kapton tape on the bottom to protect the plastic from all the heat. This way, the plastic lasts longer.