GRBL Settings For My IndyMill Build

I started with the Grbl v1.1h Configuration and then from UGS ran Machine -> Setup wizard, changing the settings I noted the $ values.

Additional commands I added as Macros are under Install UGS On Pi4

Misc

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POS           DESC                                          WHY I CHANGED IT
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$0=10         (step pulse time, microseconds)
$1=25         (step idle delay, microseconds)
$2=0          (step port invert, mask)
$3=5          (dir port invert, mask)                        ~ this inverted X and Z
$4=0          (invert step enable pin, mask)
$5=1          (invert limit pins, boolean)                   ~ after adding opto-isolator (ILD213T)
$6=0          (invert probe pin, boolean)
$10=1         (status report options, mask)
$11=0.010     (junction deviation, millimeters)
$12=0.002     (arc tolerance, millimeters)
$13=0         (report in inches, boolean)
$20=0         (soft limits enabled, boolean)
$21=1         (hard limits, boolean)                         ~ enable the limit switches
$22=1         (homing cycle, boolean)                        ~ enable homing
$23=3         (homing direction invert, mask)                ~ this inverted X and Y
$24=25.000    (homing locate feed rate, mm/min)
$25=500.000   (homing search seek rate, mm/min)
$26=250       (homing switch debounce, microseconds)
$27=1.000     (homing switch pull-off, millimeters)
$30=1000      (maximum spindle speed, RPM)
$31=0         (minimum spindle speed, RPM)
$32=0         (laser mode enabled, RPM)

Cartesian – [X,Y,Z] steps/mm

Stepper motor steps:

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motor_steps = degrees_in_a_circle / stepper_motor_step_angle
motor_steps = 360 / 1.8
motor_steps = 200

Driver micro steps:

(typically 1, 2, 4, 8, or 16). Using high microstep values (ie 16) can reduce your stepper motor torque, so use the lowest that gives you the desired axis resolution and comfortable running properties.

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microsteps are calculated based on the dip switchs on the stepper drivers
mine is pre set to 8 so I rolled with it as Im a noob

MM per revolution:

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1605 ball screws for x,y
05 means 5mm for 1 full rotation

the z has is 8mm on the trapezoidal lead screw

Finally some math:

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x,y
steps_per_mm = (steps_per_revolution*microsteps)/mm_per_rev
steps_per_mm = (200 * 8) / 5
steps_per_mm = (1600) / 5
steps_per_mm = 320

z
steps_per_mm = (steps_per_revolution*microsteps)/mm_per_rev
steps_per_mm = (200 * 8) / 8
steps_per_mm = (1600) / 8
steps_per_mm = 200

Now the resulting GRBL:

XYZ Axis - Cartesian Coordinate System

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$100=320       (x, step/mm)
$101=320       (y, step/mm)
$102=200       (z, step/mm)

Also see grbl settings 101 a how to guide

Rates, Acceleration, Max Travel

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POS            DESC                                          WHY I CHANGED IT
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$110=500.000   (x-axis maximum rate, mm/min)
$111=500.000   (y-axis maximum rate, mm/min)
$112=500.000   (z-axis maximum rate, mm/min)
$120=10.000    (x-axis acceleration, mm/sec^2)
$121=10.000    (y-axis acceleration, mm/sec^2)
$121=10.000    (z-axis acceleration, mm/sec^2)
$130=320.000   (x-axis maximum travel, millimeters)          ~ max corner to corner was more than 200
$131=255.000   (y-axis maximum travel, millimeters)          ~ max corner to corner was more than 200
$132=200.000   (z-axis maximum travel, millimeters)