Assembly of my all metal version of the Mk8 import extruder
Click on the images for more detail.
Plug it in
You will need power to both sides of the green plug, you can just add a short jumper wire from one side to the other. The polarity is marked on the board, double check to make sure this is correct. The fan on the heat sink needs to always run, this gets plugged directly into the green power plug, polarity matters. Extruder to port D8, polarity does not matter. Optional print fan plugs in to port D9 polarity matters.
Marlin edits
Very few edits required. Any firmware I release after this post will most likely already be set for this extruder by default. I will put the info here for you adventurous types.
All of these that I have gotten have used the marlin #11 thermistor, and at 32nd stepping I use 200 steps for the e value.
#define TEMP_SENSOR_0 11
and
#define DEFAULT_AXIS_STEPS_PER_UNIT {200,200,4535.44,200}
Even after running the PID auto tune I get a huge overshoot in temp so limiting the max current might help with this, I will update it when I get a chance to test it.
// Comment the following line to disable PID and enable bang-bang.
#define PIDTEMP
#define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
#ifdef PIDTEMP
Slicer edits
Delete the beginning gcode, you don’t want it to home.
Change the end gcode to look like this
G91
G1 E-5 ;retract
G1 Z5 ;lift up 5mm
G90
M104 S0 ; turn off temperature
M84 ; disable motors
Not using endstops
Position you parts on the lower corner (0,0,0), before you slice them. This will start your prints where ever your head is. So position the nozzle touching the bed and exactly where you want it to start. When the print begins it should lift up the correct amount and print. You can manually adjust the height during the skirt print to fine tune it.
That’s it print away. The printed parts I am shipping are starting to get printed on this cnc, and they look amazing.
Recommended beginning slic3r settings.
Test file just in case.