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MK8 Extruder Assembly and Configuration Guide

IMPORTANT NOTE about extruder kits sold with stepper motors

  • If you are upgrading your printer with our bowden feed extruder and stepper motor, please make current adjustment on the stepper driver that drives the extruder to match requirement of new stepper motor. Do not assume your new extruder stepper motor will work in place of old one without adjustment. Stepper motors are not equal, they have different coil parameters and there is a god chance that you need to turn the trim pot in order to new stepper motor to work and produce enough torque.

Firmware configuration for this extruder

Calculating Esteps for the extruder is simple:

  • Please take into an account filament gear driving diameter - 10.95 mm and calculate circumference of the gear - 10.95 x 3.14 =   34.38mm.
  • Next calculation step will depend on the type of stepper motor you use and stepper driver setting. Let's take widely used 1.8 deg/step stepper motor with stepper driver settings of 1/16 step. 1.8 deg/step stepper will have 200 steps per one full rotation. We multiply that by 16, because 1/16 setting on the driver will give 16 times of 200. 16 x 200 = 3200 steps per rev with 1/16 stepper driver settings.
  • Last step is calculate actual Estep parameter to put into firmware. It will be 3200 / 34.38mm = 93 steps per mm. Use this value in the firmware.
  • To further improve it, you can calibrate Esteps value as described in Triffid Hunter's Calibration Guide

Extruder assembly

MK8 Extruder Kit
Package contents
Aluminum block, lever, filament gear, v-groove bearing, compression spring, M3, M4 and M6 screws.
 
Assembly Step 2
Screw on second M3 Philips head screw into a hole position shown on picture. This screw will work as a retainer, to hold compression spring in place.
 
Assembly Step 2
Screw on second M3 Philips head screw into a hole position shown on picture. This screw will work as a retainer, to hold compression spring in place.
 
Assembly Step 3
Screw on V-groove bearing into M3 hole on aluminum lever. Use large button head M3 screw to hold bearing.
 
Assembly Step 4
Install Aluminum lever with M3x16 socket head screw. Screw on Lever to the extruder block completely and then loosen up just a little bit to allow lever movement. Secure filament drive gear on the stepper motor shaft with sets screws.
 
Assembly Step 5
Screw on long M4 screw into a lever. It will work as tension adjustment screw. After that, insert compression spring as show on the picture. Large M6 screw should meet M4 screw, hold spring in a position and allow for tension adjustments.
You have completed MK8 extruder feeder configuration and assembly. Next steps will depend on how you are going to use this feeder, which extruder you will make using it.
 
Two ways of using extruder feeder 
  • To complete assembly as direct drive extruder, you will need to use M6x1 threaded heatbreak tube, heater block, nozzle, heater and thermistor. Additionally you might need 40x40x10mm fan and 42x42mm heatsink..
  • For bowden line extruder you will only need one PC4-M6 straight tube fitting and piece of 4mm OD 2mm ID PTFE tubing.