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Before you start, you need a way to send commands to the printer. You can use the USB cable to hook the printer to your computer, use a Raspberry Pi, or you can even write the commands you want on to files you put on your SD card. But you will need the command results and those only are repeated on the serial connection. Repetier is your best shot, IMHO, to get this working quickly.

  1. Set endstops using Repetier procedure. You can find the repetier documentation at https://www.repetier.com/documentation/repetier-firmware/z-probing/

That procedure is: Clear existing endstop settings with

G28
G131
  • Get a metal rule or even a stiff stick that will fit between your printer base and your extruder carriage. I use a 30cm metal rule
  • Disable each motor individually, one at a time, with
M99 [X!Y!Z]0 [S10]
M99 X0 S20
M99 Y0 S20
M99 Z0 S20
  • These M99 command unlock the corresponding motor for 20 seconds. If you leave off the "S" parameter it defaults to 10 seconds. Enter the M99 commands one at a time and then move the tower trucks, one at a time, to an exact position based on your ruler or stick just fitting between the truck and the base - careful of wires. i like to let the motor lock before pulling the ruler out. remember you can repeat a command in repetier with up arrow.
  • Issue the following command:
G132 S1
  1. Now the endstops are set. IMHO this is much simpler than the Marlin procedure.

At this point, you have two choices. If you have a working Z probe, you can set the distance from the endstops to the bed automatically, If not, you have to do it manually, so, with your Z probe hooked up and pressed over your nozzle, issue the command

M119

See if the endstop is triggered - it should show "L" or not triggered. Now push the endstop and issue the M119 command again. The probe should show "H". If the endstop won't trigger you are not going to be able to use the automatic procedure.

I plan on expanding this, but these are the basic steps you need to finish:

Let's presume you are using Repetier Host. Under Manual Control there are macros that you can set. If you are using octoprint you will have to type the commands but you can repeat them by pushing the up arrow in the terminal window. You should set all five macros. For a K280, your settings should be:

Macro 1:
G1 X-104 Y-60 Z5 F7000

This setting quickly moves the head in front of the X tower. All these macros use a Z of 5.

Macro 2:
G1 X103 Y-60 Z5 F7000
Macro 3:
G1 X0 Z5 F7000 Y120
Macro 4:
G1 X0 Y0 Z5 F7000
Macro 5:
G0 X0 Y0 Z540 F5000
G28

This last macro is for fast homing - if you have partial position, like when you adjust radius at 0,0 and you have to rehome, it moves most of the way and then does a regular home. It won't work if the printer has completely lost its position.

Those are the macros I use. To calculate your own, you can convert polar to rectangular coordinates. For a printable volume of 180mm diameter, we want to move the print head to 0 degrees, 85mm, then 120 degrees 85mm, and then 240 degrees, 85mm. So 0 degrees is X -85, y 0. 120 degrees is X 42.5, y -73.62.and 240 degrees is X 42.5, Y 73.62. Substitute those into the above macros.

  1. Set the approximate Z distance in eeprom (alt-e in repetier) - the eeprom settings are all explained and when you save them the eeprom is modified. Start by exporting your settings before any changes, you may need to restore.

Level the print bed manually - even with auto leveling this is a good idea - final calibration of Z distance. You can also use G33 until all distances are correct. The measurement points should be in front of the towers and close to the edge. Use the above commands and move the Z to a safe height then slowly lower it to the bed. Set the perimiter points using the bed adjustment.

At all three towers and extruder descended to 0, paper should drag. 

4. Get it printing flat by adjusting radius at 0.0 in eeprom. This is a trial and error thing and you need to home between changes. Use the above repetier shortcuts and use the center position. This procedure is where you need the fast home because every time you change 0,0, you should home, then check X, Y and Z towers, and then check the center.

5. Calibrate extruder

6. Calibrate your hotend. The article linked explains how to set up your hotend for proper PID control, automatically determining the parameters, and changing your EEPROM as needed.

6. Print the item at http://www.thingiverse.com/thing:1274733 then measure it, plug those measurements into the spreadsheet and then put the output of the spreadsheet into your eeprom https://www.repetier.com/documentation/repetier-firmware/z-probing/

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