BL touch - fast homing?

  • Eager to establish a strategy for fast Z homing using BL-touch tried the following:

    G1 Z5 F800 S2
    G1 X150 Y150 F2400
    M558 F500

    G1 Z5 F800 ; axis has now been homed, move down relative

    M558 F50 ; now do an ultra precise homing
    G1 Z2 F200

    It sort of went pear shaped. I think the problem is that during the F500 move the axis moves down and then up so quickly for the second probing (there are usually two within a G30) that the probe has not yet deployed. Hence by the time the probe is deployed and the second probing occurs the bed tends to already be touching the nozzle!

    Would rather go easy on the trial and error. Any suggestions?

  • Moderator

    Here's what I use in homeall and homez:

    ; Probe the bed
    M558 A1 F400	; Set single probing at faster feed rate
    G30 	; Do a single probe to home our Z axis
    M558 A10 F100	; Set tripple probing at slower feed rate
    G30	; Probe again to get a more accurate position

  • @phaedrux Genius!

    btw. you say "triple" having set a max of 10. Does the BLT tend to make 3 attempts? I set a max of 5 in config.g and it usually does just 2.

  • Moderator

    Yeah sorry, it should really say multi probing. It will do up to 10, until 2 results are consistent. So at least 2.

  • @phaedrux post that code on twitter so it can go viral. It's great! 😉

  • Moderator

    Careful, posting viral code to twitter is likely to result in a visit from the authorities. 😉

  • administrators

    @r123 said in BL touch - fast homing?:

    Would rather go easy on the trial and error. Any suggestions?

    Are you using the R parameter in M558 to delay probing a little? If not, try it.

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