Z Height between nozzle tip and heatbed not correct



  • Hi Guys,
    I am having a problem when i begin a print. I use Cura to create the Gcode with reprap flavor.
    when i send the gcode through Duet wifi, it starts the print , but distance between nozzle tip and heatbed is way off.
    I have leveled my heatbed according to the bed leveling instructions on the duet website, i have 4 heatbed screw locations. And the heatbed is leveled very well. About 0.15 mm away from the tip in all 4 positions. I am not using any probe, just nozzle. My config file, for the z min max limits are as follows ( 0 and 190.15 ) mm
    Can someone shed some light. Shouldnt the print start exactly at 0.15mm ( distance between nozzle tip and heatbed )
    I also looked at the config file, and z offset is set at zero.



  • The Z endstop need to be adjust to trig when the nozzle touch the bed, then do the Z offset calibration, the Z offset in G31 must be positive.
    If your switch that triggers a little before Z=0, then you can't use M208 to define the homing position, because it would prevent you moving below the trigger height.
    How the Z endstop is mounted ?



  • Hi,

    I level my bed manually using adjustment screws as you do.

    Often folks are told to use something very thin, like a piece of paper, to establish the gap between NOZZLE and BED when the Z position is 0.

    I don't do that because I have a CCTREE build surface and the nozzle can make depressions in it leading to faulty adjustment.

    So I use a 1 mm thickness gauge to set the gap when the Z position is 1 (not 0 as with paper).

    So if you use my approach the goal is to be able to move the nozzle to any X,Y point on the bed, then move to Z=1 and have the gauge slip between the nozzle and the bed with just a little bit of drag.

    The position of the nozzle at the start of the print is controlled by the slicer and it's current settings and is not really relevant to manually leveling the bed.

    Frederick



  • @ScaraMan said in Z Height between nozzle tip and heatbed not correct:

    Shouldnt the print start exactly at 0.15mm ( distance between nozzle tip and heatbed )

    no then the print would start at 0.15 + your layer height.



  • HI
    My setup for the endstop on the Z axis is similar to Ultimaker 2, the switch is triggered when heatbed reaches max
    limit and its at the bottom, when it homes , heat bed lifts according to z max value set in config, and homez and home all.


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