Bed probing feed rates

Question

I was watching a friend's Prusa run the bed-probe routine and I realized how pathetically slow mine is and takes forever. I want to speed it up.

What parameters in Marlin's Configuration.h do I modify? Also, it seems to retract for the second "accurate" probe by like 10 mm which could be reduced by 8 mm or so. Where is that one? I looked through but can't be sure. Also, could I just change the feedrate in the pre-script?

#define DEFAULT_MAX_FEEDRATE { 300, 300, 8, 50 }    // was { 400, 400, 8, 50 }

Answer 1

To speed up the probing for a touch sensor, a "High Speed" option is available in Configuration_adv.h which is by default disabled (//#define BLTOUCH_HS_MODE) as not all printers/sensors are able to use this.

You can also increase the homing speeds in your Configuration.h file.

// Homing speeds (mm/min)
#define HOMING_FEEDRATE_XY (50*60)
#define HOMING_FEEDRATE_Z  (4*60)

.
..
...
..
.
// Feedrate (mm/min) for the first approach when double-probing (MULTIPLE_PROBING == 2)
#define Z_PROBE_SPEED_FAST HOMING_FEEDRATE_Z

// Feedrate (mm/min) for the "accurate" probe of each point
#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)

However, you can simply speed up the movement between probe locations by setting the movement speed directly through G-code. The G29 code, used for automatic probing of the bed surface is described in "G29 Auto Bed Leveling (Marlin - MK4duo)". The S parameter in G29 can be used to set the movement speed between probes, where the units are specified in "units/min", e.g. mm/min.

Note that you potentially can change the Z-height for deployment:

/**
 * Z probes require clearance when deploying, stowing, and moving between
 * probe points to avoid hitting the bed and other hardware.
 * Servo-mounted probes require extra space for the arm to rotate.
 * Inductive probes need space to keep from triggering early.
 *
 * Use these settings to specify the distance (mm) to raise the probe (or
 * lower the bed). The values set here apply over and above any (negative)
 * probe Z Offset set with NOZZLE_TO_PROBE_OFFSET, M851, or the LCD.
 * Only integer values >= 1 are valid here.
 *
 * Example: `M851 Z-5` with a CLEARANCE of 4  =>  9mm from bed to nozzle.
 *     But: `M851 Z+1` with a CLEARANCE of 2  =>  2mm from bed to nozzle.
 */
#define Z_CLEARANCE_DEPLOY_PROBE   10 // Z Clearance for Deploy/Stow
#define Z_CLEARANCE_BETWEEN_PROBES  5 // Z Clearance between probe points
#define Z_CLEARANCE_MULTI_PROBE     5 // Z Clearance between multiple probes
//#define Z_AFTER_PROBING           5 // Z position after probing is done