Anet MK8 extruder filament guides

thingiverse

Inserting filament through the Anet extruder into the nozzle throat can be a struggle because the extruder design has open space beside the right filament track. Especially with bended filament or with flexible filament this can lead to a lot of frustration. Also the stock extruder is not suitable for flexible filament because the filament has no tight guiding after the drive gear. I designed two extruder filament guides to solve this issue. One for stiff filament like PLA, ABS or PETG and one for flexible filament such as TPU. These guides guide the filament in the best way for inserting en while printing. The stiff filament guide give the best insertion guiding but the stroke of the U-groove bearing to the drive gear is restricted. The complete stroke is not needed with stiff filament. The stiff filament guide partly fills this gap for easier insertion. The flexible filament guide don't have the stroke limitation. Soft filament compressed much more, therefore the U-groove bearing must be able to hit the drive gear. The guide remain in position because it is mounted over the stepper motor shaft and is trapped between the stepper motor and heat sink. Installation is simple. Turn the printer off and unscrew the two bolts that are screwed in the stepper motor trough the fan and heatsink. Always compress the extruder while un/screwing these bolts. Unscrew the extruder lever hinge bolt. Place the guide over the U-groove bearing and slide the guide over the stepper motor shaft. Screw the hinge bolt back in and re-assemble the fan with heatsink. The drive gear may need to be turned so that its clamp bolt is on the stepper side. Also adjust the drive gear position on the motor shaft so it don't hit the guide. Adjust the open position of the extruder with the bolt in the lever so that it cannot be opened further than necessary. Both guides are in two variants, with and without a counterbore hole of 1mm depth that give clearance for the throat that can stick out. The designed support for the counterbore hole can be easily removed with a suitable flat head screwdriver. If you have a 0.2 mm print nozzle instead of 0.4 mm, I recommend to print the stiff guide version 0.2. The stroke of the U-groove bearing to the drive gear is less restricted what can prevent filament grinding or under-extruding with some softer filament. 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 it has good printing properties and hardness.