marlin/config/examples/Geeetech/Prusa i3 Pro B/noprobe/README.md

These are example configurations for the low-cost Acrylic Prusa I3 pro B 3D Printer DIY kit and the 3DTouch auto bed leveling sensor based on:

• ../GT2560/
• Marlin 1.1.4 With 3DTouch / BLTouch for i3 Pro B

The main characteristics of these configurations are:

• The defined motherboard is BOARD_GT2560_REV_A_PLUS.
• Travel limits are adjusted to the printer bed size and position.
• An example SKEW_CORRECTION for a particular printer is enabled. See comments below about how to adjust it to a particular printer.
• Using the LCD controller for bed leveling is enabled.
  • PROBE_MANUALLY is enabled, which provides a means to do “Auto” Bed Leveling without a probe.
  • The LEVEL_BED_CORNERS option for manual bed adjustment is enabled.
  • Bilinear bed leveling is enabled, the boundaries for probing are adjusted to the glass size, and extrapolation is enabled.
• PRINTCOUNTER is enabled, in order to track statistical data.
• INDIVIDUAL_AXIS_HOMING_MENU is enabled, which adds individual axis homing items (Home X, Home Y, and Home Z) to the LCD menu.
• The speaker is enabled for the UI feedback.
• bltouch variant:
  • USE_ZMAX_PLUG is enabled. See comments about connections below.
  • Heaters and fans are turned off when probing.
  • Multiple probing is set to 3.

First-time configuration

Skew factor

The skew factor must be adjusted for each printer:

• First, uncomment #define XY_SKEW_FACTOR 0.0, compile and upload the firmware.
• Then, print YACS (Yet Another Calibration Square). Hint, scale it considering a margin for brim (if used). The larger, the better to make error measurements.
• Measure the printed part according to the comments in the example configuration file, and set XY_DIAG_AC, XY_DIAG_BD and Y_SIDE_AD.
• Last, comment #define XY_SKEW_FACTOR 0.0 again, compile and upload.

3DTouch auto leveling sensor

• Print a suitable mount to attach the sensor to the printer. The example configuration file is adjusted to http://www.geeetech.com/wiki/images/6/61/3DTouch_auto_leveling_sensor-1.zip
• Unlike suggested in geeetech.com/wiki/index.php/3DTouch_Auto_Leveling_Sensor, the existing end stop switch is expected to be kept connected to Z_MIN. So, the sensor is to be connected to Z_MAX, according to Marlin’s default settings. Furthermore, GT2560-A+ provides a connector for the servo next to thermistor connectors (see GT2560 and GT2560-A+).
• Be careful to respect the polarity of the sensor when connecting it to the GT2560-A+. Unlike end stops, reversing the connection will prevent the sensor from working properly.
• Test and calibrate the sensor.
• If using the GT2560-A+ and with the sensor connected to Z_MAX and an endstop connected to Z_MIN use the following calibration routine instead.

3DTouch Calibration with Z_MAX

• Home the printer with G28 command.
• Disable the Z axis software endstop with M211 S0 Z0
• Reset the probe Z_OFFSET with M851 Z0
• Move to the center of the bed with G1 X100 Y100
• Move Z incrementally until the nozzle is the correct height from the bed using a shim or piece of paper, record this Z movement, for example -0.2.
• Do a single probe at the current point in the middle of the bed using G30 and not the returned value, for example 1.9. Invert this value, i.e. -1.9, and add it to the Z offset above, i.e. -0.2 in this example giving -2.1.
• Update the probe Z_OFFSET to this value using M851 i.e. M851 Z-2.1.
• Re-enable software end-stops with M211 S1 Z0
• Save this value to the EEPROM with M500.
• Update the start G-Code in your slicer software to insert a G29 after the last G28.
• Carefully test that the offset is correct in the first print.