Easy exchange filament extruder

For a new printer I needed an extruder setup.

Because I print with ABS a lot this one is designed to do just that (but it also works with other filaments).
With ABS printing you do not want to have airflow passing the printed parts.
Therefor the air is inhaled from above. Then passed through to the Hot-end and then back out at the top. The same airflow construction is also made for de motor. This way the printed part never gets cooled by these 2 fans. For the dimensions of these snail house fans, see picture.

Also I wanted an extruder on which changing filament is easy. On most extruders you can’t see the filament wire and that can make it hard to change filament. If you run out of filament due the print, you are in big trouble. Therefor I made this one in such a way that you can always see the filament wire.

Because I have 3 different sizes of Filament (1.75mm, 2.85mm & 3mm) this extruder can use them all.
To do this I have made an exchangeable filament wire gide. For the 1.75 mm filament I also need to put in a Teflon tube because the hot-end is made for 3mm wire. (I can recommend the Teflon tube anyways because the filament go’s in much smoother). The filament gide is also adjustable so you can gide you filament perfectly. In the photos you do not see this gide because that is still the proto type. On that model the 3mm gide is fixed to the body. Not so smart, because you can’t adjust anything anymore. Also I broke it :-) . As a lose part you can just print it out again. The gide is mounted using a washer, M3 nut and 10mm bolt.

The little filament driver (11mm diameter) is mounted on an M8x50mm bolt I had lying around. On the lathe I turned the end of this M8 bolt down to 5mm so the driver can be mounted on it. See pictures.

The Hot-end is a cheap Chinese one I do not even know the name of, but it works very good. For the dimensions of this Hot-end see pictures.

The stepper motor is a Nema 17 x 47mm. I recommend a strong motor for this if you want to use 2.85 & 3mm filament wire. In the picture you see a 42BYGHW811, but I use an SL42S247A at the moment (a bit more torque). As a driver I still use an A9844 with heavy cooling and heat sink.

For the main body I had to add support material. See picture about the removal of the support material. All other parts can be printed without support. I have printed all parts in PET-G 0.2mm resolution and a 0.4 nozzle

You 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 gide
8X M4 nut
5X M4 x20mm bolt
1X M4 x40mm bolt
5X M4 washer (optional)

After assembly it is wise to put katon tape on the bottom to protect the plastic from all the heat.
This way the plastic holds longer