Lulzbot Mini Extruder v2.1 dual fan modification

Lulzbot Mini printer doesn't have the space to support a dual fan configuration similar to that of TAZ. I came up with a solution of easily attachable second fan. When the print job is suitably small I can attach the secondary fan. The print job has to be small enough in order to run till the end without issues. Note that the fan should always be attached after the bed auto leveling process. The removable fan has an end stop trigger that prevents the fan from colliding during the end of each print session.

Be careful: If the print job is too large and the fan is attached it can brake something!

Secondary fan is fixed with 5 cylinder magnets size 6 x 3 mm. Extruder mount has a wiring harness to snake the power cables to the secondary fan mounting point. The fan is powered through two magnets.

Model has 2 versions. I recommend the 65 deg version:

• 68 deg: Lulzbot extruder v2.1 has different tilt angle for the fan than originally. Maybe the manufacturer finds the single fan is more effective when tilted more towards the hot end. I tried this setup in dual fan configuration (orange printed parts). It cools the hot end considerably with high fan speeds. I found it difficult to maintain even 240 C temperature when both fans are blowing.
• 65 deg: I modified the v2.1 extruder mount to have the same angle as originally (green printed parts). This eliminates excessive cooling of the hot end and in my opinion is a better compromise than the 68 deg version.

When soldering the wires to magnets I found it necessary to protect the magnet against loosing the magnetism during heating. To do so one needs a bigger strong magnet underneath the soldered magnet during the process. I used spherical magnet to avoid head conduction from soldered magnet. Then I used a bigger cylinder one underneath the sphere to further protect the magnetic field.

EXTRA: I also created a modification of the heatsink fanduct. I found that the fans I have are unnecessarily powerful in cooling the heatsink. I guided half of the air flow to the stepper motor. This makes me less worried about the stepper motor lifetime when I use the printer inside a heated chamber.