Anet MK8 extruder filament guides

Inserting filament into the Anet extruder can be a struggle because the extruder parts don't guide the filament well to the nozzle.
With bended filament and especially with flexible filament is this is almost impossible.
Also the extruder is not suitable to print with flexible filament because the filament has no good side guiding from the drive gear to the throat.

I designed two extruder filament guides to solve both issues. One for the stiff filament like PLA, ABS or PETG and one special for flexible filament like TPU.

The stiff filament guide give the easiest insertion guiding. The maximal impression of the drive gear tooths into the filament is restricted, wich is also not needed with stiff filament.

Soft filament can be compressed much more than stiff filament. Therefore the flexible filament guide don't have the stroke limitation between the drive gear and U-groove roller. The U-groove roller must with soft fillament be able to hit the drive gear for maximum drive force.

The guide remains in position because it's fixateted on the stepper motor shaft, and is in between the heat sink and stepper motor.

Installation:

• Turn the printer off and unscrew the two bolts that mounts the fan and heatsink to the stepper motor. Compress the extruder while screwing or unscrewing these bolts
• Unscrew the extruder lever hinge bolt
• Slide the guide over the U-groove bearing and stepper motor shaft and reassemble all parts

Note:
The drive gear may need to be turned, so that it's clamp bolt is on the stepper motor side. Also adjust the drive gear position on the motor shaft so that it don't hit the guide.
Adjust the extruder open position with the bolt in the lever so that it cannot be opened more than necessary.

Both guides are added in two variants. With and without a counterbore hole with 1mm depth that give clearance for the throat that can stick out.

The print support for the counterbore hole guide can be easily removed with a suitable flat head screwdriver.

If you own a 0.2 mm print nozzle, I recommend to print the insert guide stiff 0.2. The stroke of the U-groove bearing to the drive gear is less restricted what prevent filament grinding and this version give better insertion guiding.

The filament transit hole in the extruder lever has a ledge that also makes filament insertion difficult. Here the entry guide can be inserted for a smooth filament insertion through the lever.

Print the guides with a 0.1 mm layer height setting and 100% infill.
Use PLA filament because its good printing properties and hardness.

Updates:
03-29-2022 improved entry guide