CORE XY 3D Printer - Getting up and running

Getting the Printer up and running.

Now its time to get the printer up and running. I like to approach this step by step bringing the various features of the printer online one by one.

This makes debugging easier and gives confidence that each part of the printer is correctly working.

When connecting wires always make sure the board is powered off!

Power to the MKS Board and config

Ensure the DC Buck converter is producing 12V (voltmeter) and connect it to the 12V POWER pins on the MKS Board. If not adjust the screw on the Buck converter.

Connect the ribbon cable of the TFT screen to the board here:

Ensure the config.txt file from my GITHUB site is on the micro SD card and insert it into the MKS Control Board.
Ensure the Config files (from my github site) for the TFT are on the SD card and insert it into the TFT display Sd card slot.

The SD card must be maximum 8GB in size and formatted to FAT32.

Power on the MKS board - you should hear lots of beeps and the TFT screen should also power up. if its the first time it will install all the software from the SD cards
Power off the board

Stepper Motors

Plug in the X axis lead to the MKS board as below - The X Axis stepper should be the back right stepper motor when looking from the front of the printer.

Power on the board again - go to the option "Move" on the TFT touch screen

The following menu appears. The top right button is the feed-rate 0.1mm / 1mm / 10mm which can be adjusted by pressing it.

Change the feedrate in the menu to 10mm and then press X+ or X- to jog the printer.
Don't worry if the printer head moves in a funny diagonal direction. You need both X and Y steppers working correctly to make it move as it should... but the printer axis should move and the X stepper motor should turn.
If the stepper doesn't turn or makes funny stuttering noises, then the wires to the stepper are mixed up.... (which will take time to sort out) i.e. you need to find the right combination of black, red, blue, green wires to stepper motor. swap black to red and so on until you have it correct.
With the MKS board powered off, swap wires, then power up the board. Try to jog the X axis again. Keep doing this wire swapping process until the stepper moves smoothly.
Do this same thing for the Y and Z axis steppers (Plug in the lead to the MKS board - check movement). You cant check the filament extruder stepper motor yet as it wont move unless the head temp is above 180c. (safety feature) -

(If you want to test that motor too you need to plug it into the X,Y or Z axis port and test it like that)

With the X,Y,Z steppers connected and running you can now check the printer axis direction

Press X+ or X- and the printer head should now only move in the X axis.
Press Y+ or Y- and the printer head should now only move in the Y axis.

If the printer axis is moving in the wrong direction. i.e. you press X+ and it moves in the negative direction (left), then you can change this in the config file on the micro SD card.

Modifying the MKS Base Config File

Open the MKs board config file from the micro SD card on your PC. The MKS board uses the following names

Alpha = X / Beta = Y / Gamma = Z / DELTA = Extruder

On the line (Alpha/Beta/Gamma)_dir_Pin add a ! after the number

(there is one already on the gamma line in the code below)

or remove the ! if there is one already. This swaps the direction of the motor.

After the changes, save the file and reinsert the micro SD card into the MKS control board. Power on the board and it will update the board with the changes from the config file.
Make sure all axis are moving in the right direction by changing the config file and re-booting. Observing from the front of the printer:

Z- is up and Z+ should send the bed lower)
Y+ is sending the head to the back of the printer / Y- to the front
X+ sends the head to the right / X- to the left

Limit Switches

Power down the MKS board and plug the limit switches into the MKS board. Xmin / Y min and Z min.

Power on the board and in the TFT menu select the Home menu

Here you can send the print head to the home switches. Make sure your limit switches are correctly installed and will activate if the head touches them

(remember the Z axis requires an M3 screw in the Hot Bed bracket to activate the switch - Otherwise the bed will hit the printer nozzle)

Let's try to home the X axis first.....

Get ready..... if the head moves off in the wrong direction then turn off the printer fast. (this shouldn't really happen if you use my config file and the axis are moving in the right direction)

If X homes correctly. then do the same for Y and Z

Heating Power and Thermistors

Power off the board and plug in the thermistors for the HotEnd and HeatBed into the MKS board

Check in the config file which thermistor pins are being used. Here 0.23 for the heat bed and 0.24 for the HotEnd

(As you can see the board can be configured however you want it to be simply by modifying the config.txt file......)

Now go to the Preheat menu and check the temp readings are ok.

Check that the heat bed and hot end (Exturder) are showing something like 20c or room temp. If they show 0 on the left hand number something is wrong with the thermistor. Either its a different thermistor than in the config file, its plugged in the wrong port on the MKS board, or there is a wrong connection somewhere
To change between reading the temperature on the Bed or Hot End (Extruder) press the HeatBed or Extruder1 button to toggle.

Now connect the HotEnd (Extruder1) heater cable to E1 on the MKS board (polarity doesn't matter on the HotEnd heater wires) and the HotEnd cooling fan (front fan) to the 12V Power Terminals (+ve and -ve). Ensure when you turn the printer on that the HotEnd fan starts.

Now connect the HeatBed (BED) control wires from the MKS Board to the MOSFET (Polarity is important!!). The MOSFET is fed with 24V power direclty from the DC power supply. The wire from the MKS board to the MOSFET is just a switching voltage of 12V. Please ensure this wire is connected to the BED ports on the MOSFET. The heater bed wires from the MKS board are then connected go to the BED+- ports on the MOSFET (NOT SIG)

Power on the MKs board and select again the Preheat menu

Select the HeatBed on the TFT screen
Select steps of +10c and press the Add+ button until a setpoint temperature of 50c shows next to actual bed temperature.

The MOSFET LED at this point should light red, showing that power is switched to the heat bed. The heat bed should start to get hot.
Monitor the MOSFET temp and check to see that it remains cool. Check that the MOSFET on the HeatBed switches off at the setpoint of 50c
If the MOSFET gets hot, turn off the printer immediately. There is probably a setting wrong in the config file or a wiring issue ("Bang Bang Heater" should be set to true)
If the HeatBed is working correctly, change the HeatBed menu on the TFT to Extruder1 and set the temp to 200c.
With the same method the HotEnd (extruder) heating can be tested.
When finished press close on the TFT menu for both HeatBed and HotEnd (Extruder1) to turn off the heating and return the setpoint to 0.

Additional Head Cooling Fans

The two additional 12V cooling fans either side of the HotEnd need to connected in parallel (+ve to +ve and -ve to -ve). This parallel connection then needs to be connected to the MKS Board.

Power on the MKS board and in the TFT Menu go to settings and then FAN

Then select 100% in the Menu

Check that both left and right fans are spinning. Press 50% and check that the fans now spin at half speed. Press 0% and check that the fans turn off.