Laser Head Crashing into Gantry

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If you have already made the recommended edits from the Configuration Adjustment Guide and your head is crashing into the gantry, this can occur for a number of reasons:

    1. Try increasing the alpha and beta currents to dial in stepper motor performance: Changing Stepper Motor Currents
    2. Ensure that your configuration file parameters and LightBurn dimensions are set up to match your bed in the below instances and that the homing direction is set properly: Setting Up the Correct Bed Size
      • If you have enlarged your bed parameters to garner slightly more workspace
      • If you have done mods to extend your bed size in the machine
      • If you have moved your controller into a new machine with a different bed size
      • If you have enlarged your bed parameters and are switching between Smoothie and GRBL-LPC, or updating the firmware, it will default back and will need to be modified again
    3. Check if you are in inches / sec or inches / mm/sec units in the LightBurn settings and make sure that the design or shape you are working with does not exceed your bed size. The standard K40 bed size is approximately 11.811″ x 7.87402″ (300 x 200 mm).
    4. Check that the endstop / limit switches are being read properly by using the M119 command in the LightBurn Console by Testing the Endstops.
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    5. Confirm that the endstop / limit switch cables are connected properly at each end and that none of the individual wires have come loose.
    6. For optical endstops, ensure that the sensors are clear of debris.
    7. If you also have soft limit switches and they are not stopping the job when triggered, uncomment the limit switch parameters and ensure they are enabled (this does not apply for standard endstop installation):
      alpha_limit_enable true
      beta_limit_enable  true
    8. Update the max travel distance to be equal to or slightly more than your bed size measurements to ensure your endstops are actuating, but not crashing when homing:
      alpha_max_travel 302
      beta_max_travel  202
    9. Decrease the fast homing value in the config file. Try lowering to 100 or 50, until fine tuned.
      alpha_fast_homing_rate_mm_s adjusts the speed in millimeters/second (X axis)
      beta_fast_homing_rate_mm_s adjusts the speed in millimeters/second (Y axis)
    10. If the head moves opposite of what you expect, you may need to invert the direction pins by removing or adding an exclamation point on the end of the pin value in the config file:
      alpha_dir_pin 0.5
      beta_dir_pin  0.11