Nozzle Distance wrong between Homing and Printing

Hello all together,

i have a little problem an di hope anyone can help me. I have an Anet A8 with the Repetier Firmware 0.92.9. I leveld the Nozzle/Bed only with the screws under the bed. The nozzle is perfectly leveld. When i click Homing, the nozzle also has a perfect distance to the bed. But when i start a print, the nozzle has a distance to the bed, i think 0,3mm. You can see it in the Video. But i don´t know what is the problem. Can anybody help me?



Here is my Start G-Code from Cura Slicer and my Repetier Config

G21 ;metric values

G90 ;absolute positioning

M82 ;set extruder to absolute mode

M107 ;start with the fan off

G28 X0 Y0 ;move X/Y to min endstops

G28 Z0 ;move Z to min endstops

G1 Z15.0 F9000 ;move the platform down 15mm

G92 E0 ;zero the extruded length

G1 F200 E3 ;extrude 3mm of feed stock

G92 E0 ;zero the extruded length again

G1 F9000


Configuration.h

Comments

  • What is the problem? I guess your first layer height is 0.3mm so where else should the nozzle be. You can not print at z=0 as there would be no space for extrusion.
  • Hello,

    first i leveled the nozzle with the paper. The paper goes under the nozzle with a little scratching. So i have the right distance, or? Then i start a print. right now the nozzle has a distance from 0,3mm i think. i can´t measure it, because the print is running. So is it possible to lower the distance between nozzle and bed when the print is running?

    I click Homing - Distance between nozzle and bed is like with a sheed of paper
    I start the print - Distance between nozzle and bed is round about 0,3mm more
  • Sound like it is as supposed to be. As I said printing needs a distance and starts with first layer height. That is as expected.
  • If you enable babystep in firmware then you can fine tune Z while printing 1st layer.

  • MartinH,

    Thanks a lot. That was it. :)
  • edited February 2017

    Good morning,

    I have this same exact problem.  After I run Manual leveling and start a print, the nozzle is too high for the filament to stick to the bed.  This happened after I flashed over to 92.10.  Why is this happening?  I try to correct this by moving my bed closer (knobs) as I'm printing and when I try Manual leveling again, the nozzle is too close to the bed. 

    If I type G28, G1 x100 y100 z0 and then m84 and level the bed, it will print too high also.

    I might just go back to starting a print, turning the machine off and moving the nozzle around as I level.  Too bad. It really seemed like a great option.

    I will try the "babysteps".  I can pause my print and adjust it that way if needed.

  • edited February 2017
    what type of Z endstop are you using, if it is mechanical then adjust its position or activating screw so that Z0 is just touching the bed
  • I don't know.  What if I tell you that when I drop the nozzle down to Z0 I just move the nozzle around and adjust my 3 bed screws?  I don't enter any new values in software or anything.  But this is what I have been doing when I Manual Level or send commands through Repetier.  As soon as I print I have to adjust the bed again as the nozzle is higher than paper thickness.  I check to see if I had "bed coat" option but it's not.  So I really don't know whats happening.  I just turned off my machine prior to printing and adjusted the bed and restarted my print.  It's working fine.  

    Again, no idea why the other options don't work.
  • If you are doing z max homing you can adjust z length in eeprom to get lower. For z min homing make sure
    #define ENDSTOP_Z_BACK_ON_HOME 0
    Here the endstop defines where Z=0 is (it triggers) so you need to adjust the bed or endstop in that case for better z0.
  • I have this set for my machine.  Shouldn't my YXZ be 200x200x200 for the bed?
    And what should I enter for the Z max back on home?  Some thing like Z_MAX_LENGTH 199?

    #if DAVINCI==1
    #if MODEL==0
    #define Y_MAX_LENGTH 217 - ENDSTOP_Y_BACK_ON_HOME
    #define Y_MAX_LENGTH 215 - ENDSTOP_Y_BACK_ON_HOME
    #define X_MAX_LENGTH 237 - ENDSTOP_X_BACK_ON_HOME
    #define Z_MAX_LENGTH 200 - ENDSTOP_Z_BACK_ON_HOME
  • Looks like you have 200mm space so z length is 200 - whatever you set z back on home. A bit is required for autoleveling to work correct so 1-2mm should be enough making z length 199-198
  • edited February 2017

  • Sorry for the long delay in responding.  Z Length of 198 was the magic number.  Everything has fallen into place and I'm very happy.

    Thanks Support!

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