First Layer and Extrusion Problems



  • pla_unload.g pla_load.g pla_config.g Hello togehter,

    i finished my first corexy build yesterday and wanted to tune the z offset for a good first layer with your tutorial for BLtouch and independent Z leveling.

    But now i have the Problem that my z offset is way to high and i dont know where to put the new values in.

    in my config is the following line for my BLtouch:

    ; Z-Probe
    M950 S0 C"io7.out" ; create servo pin 0 for BLTouch
    M558 P9 C"^io7.in" H5 F120 T6000 ; set Z probe type to bltouch
    G31 P500 X-26 Y2 Z2.5 ; set Z probe trigger value, offset and trigger height
    M557 X50:400 Y50:400 S50 ; define Mesh Grid

    After Leveling the bed with a piece of paper and setting Z=0 with G92 Z0

    then a single measurement with G30 S-1 where i get the value of x.xxx

    when i am changing the Z value, i dont get it right. or is there something i am missing ?

    The indipendent Z Leveling seems to work just Fine.

    But my High Map is a Desaster 🙂 i tried Tue BEd Level First and then a Mesh Compensation.

    The other Problem is that my Extruder seems to skip steps and is constantly feeding to less material. The E STeps are 830 for a Original Direct Drive BMG with a E3d Volcano with 0.4 Nozzle. When i am manual Extrudiong at 225° i cant go with the speed over 5 -15 mm bevor it starts making strange clicking noises.

    Where can i set the Retractions Paramters etc. ?
    I tried using the Filaments Macros with the load, unload and config files , but i dont know if it is correct .

    Reprap 3.1.1
    Duet 3 + RPI 3b+
    0.9° Pancake Stepper on the BMG
    1.8° Z Stepper

    Tried printing PLA with 215 ° Nozzle and Bed 60°

    config (1).g
    homez.g
    bed.g
    pla_config.g
    pla_load.g
    pla_unload.g

    Kindly Regards
    Frederik



  • I dont know where i can change the offset ?
    Do i have to add a command after the BLTouch Lines or change the trigger height ?

    The dozuki only says to change the G31 , but how ?!?



  • in config.g :
    G31 P500 X-26 Y2 Z2.5 <= modify the Z, increase value for reduce height of nozzle



  • ok thanks , one moment i will try it



  • Is the Right way to do a bed leveling:

    first G32
    then G 28
    and then adjusting for the right layer height ?

    This is my First Printer build 🙂



  • G29 S1 ; Load previously set bed map

    this should not be in the config.g

    the mesh should be loaded after you have established z=0

    so a good place is the start of your slicer g code

    for the offset see
    https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe#Section_Calibrate_the_Z_probe_trigger_height



  • when i run first a true bed level and then a bed mesh compensation i get the following heightmap:

    RepRapFirmware height map file v2 generated at 2020-11-20 14:53
    xmin,xmax,ymin,ymax,radius,xspacing,yspacing,xnum,ynum
    0.00,340.00,0.00,370.00,-1.00,20.00,20.00,18,19
    2.000, 1.878, 1.875, 1.890, 1.685, 1.642, 1.517, 1.442, 1.358, 1.253, 1.180, 1.145, 1.135, 1.138, 1.160, 1.177, 1.250, 1.333
    1.715, 1.562, 1.735, 1.757, 1.603, 1.550, 1.423, 1.320, 1.240, 1.132, 1.075, 1.030, 1.020, 1.020, 1.048, 1.062, 1.105, 1.183
    1.683, 1.645, 1.835, 1.725, 1.558, 1.397, 1.267, 1.160, 1.070, 1.010, 0.943, 0.925, 0.910, 0.922, 0.975, 1.005, 1.022, 1.100
    1.635, 1.677, 1.760, 1.573, 1.440, 1.302, 1.163, 1.052, 0.970, 0.905, 0.847, 0.815, 0.802, 0.815, 0.855, 0.892, 0.930, 1.010
    1.603, 1.555, 1.608, 1.442, 1.285, 1.150, 1.060, 0.953, 0.833, 0.755, 0.712, 0.690, 0.685, 0.695, 0.730, 0.770, 0.818, 0.927
    1.483, 1.513, 1.510, 1.255, 1.155, 1.025, 0.943, 0.828, 0.795, 0.685, 0.597, 0.578, 0.573, 0.578, 0.613, 0.653, 0.722, 0.812
    1.440, 1.442, 1.358, 1.160, 0.998, 0.858, 0.715, 0.642, 0.648, 0.542, 0.507, 0.507, 0.510, 0.533, 0.557, 0.610, 0.675, 0.775
    1.478, 1.415, 1.267, 1.017, 0.917, 0.797, 0.743, 0.680, 0.615, 0.605, 0.432, 0.413, 0.420, 0.440, 0.455, 0.505, 0.573, 0.677
    1.355, 1.205, 1.100, 0.875, 0.770, 0.672, 0.648, 0.590, 0.523, 0.417, 0.307, 0.300, 0.312, 0.333, 0.352, 0.392, 0.455, 0.555
    1.212, 1.145, 0.953, 0.783, 0.632, 0.550, 0.560, 0.490, 0.360, 0.280, 0.203, 0.208, 0.225, 0.233, 0.238, 0.292, 0.352, 0.453
    1.112, 1.010, 0.820, 0.632, 0.493, 0.390, 0.395, 0.347, 0.243, 0.158, 0.092, 0.100, 0.127, 0.120, 0.127, 0.163, 0.215, 0.333
    1.005, 0.875, 0.705, 0.480, 0.358, 0.243, 0.212, 0.165, 0.115, 0.045, -0.010, 0.005, 0.010, 0.007, 0.012, 0.047, 0.097, 0.212
    0.913, 0.750, 0.557, 0.318, 0.233, 0.108, 0.057, -0.002, -0.062, -0.110, -0.153, -0.148, -0.132, -0.137, -0.108, -0.068, 0.005, 0.095
    0.797, 0.625, 0.425, 0.248, 0.127, -0.012, -0.097, -0.160, -0.220, -0.270, -0.283, -0.288, -0.270, -0.265, -0.227, -0.158, -0.105, -0.023
    0.698, 0.483, 0.167, 0.115, -0.005, -0.145, -0.248, -0.302, -0.368, -0.440, -0.453, -0.475, -0.470, -0.430, -0.387, -0.315, -0.265, -0.182
    0.500, 0.312, 0.070, -0.078, -0.193, -0.310, -0.408, -0.467, -0.552, -0.592, -0.575, -0.573, -0.578, -0.547, -0.495, -0.427, -0.350, -0.267
    0.358, 0.160, -0.092, -0.172, -0.295, -0.415, -0.500, -0.573, -0.642, -0.665, -0.627, -0.595, -0.637, -0.640, -0.583, -0.515, -0.438, -0.347
    0.265, 0.068, -0.240, -0.307, -0.420, -0.557, -0.640, -0.690, -0.735, -0.715, -0.660, -0.653, -0.730, -0.743, -0.698, -0.627, -0.542, -0.432
    0.105, -0.070, -0.250, -0.320, -0.557, -0.677, -0.762, -0.797, -0.802, -0.773, -0.743, -0.795, -0.852, -0.833, -0.752, -0.670, -0.625, -0.517



  • 2020-11-20_15h00_22.png

    That is the orresponding height map picture from my DWC



  • post the output of 3 consecutive G32.

    most likely your motor order is wrong



  • 1.G32
    Leadjustments made: -2.618 -0.246 -0.521, points used 3, (mean, deviation) before (-0.997, 0.862) after (0.000, 0.000)

    2.G32
    Leadscrew adjustments made: -0.054 1.112 0.200, points used 3, (mean, deviation) before (0.399, 0.459) after (-0.000, 0.000)

    3.G32
    Leadscrew adjustments made: 0.044 0.756 -0.011, points used 3, (mean, deviation) before (0.228, 0.321) after (0.000, 0.000)



  • i´ve checked the cabling.

    left front spindle is connected to driver 2
    back center spindle to driver 3
    right front spindle to driver 4



  • Hi,

    Do you lead screws really have pitch of 1.25?

    Regards bed.g:

    I'm not sure what having two P parameters is going to do to your bed leveling.

    Why did you add the second P1.25?

    Frederick



  • @fcwilt said in First Layer and Extrusion Problems:

    Do you lead screws really have pitch of 1.25?

    he has z400. where did you see 1.25 leadscrew?
    M92 X160.00 Y160.00 Z400.00 E830.00 ; set steps per mm



  • @Frederik said in First Layer and Extrusion Problems:

    1.G32
    Leadjustments made: -2.618 -0.246 -0.521, points used 3, (mean, deviation) before (-0.997, 0.862) after (0.000, 0.000)
    2.G32
    Leadscrew adjustments made: -0.054 1.112 0.200, points used 3, (mean, deviation) before (0.399, 0.459) after (-0.000, 0.000)
    3.G32
    Leadscrew adjustments made: 0.044 0.756 -0.011, points used 3, (mean, deviation) before (0.228, 0.321) after (0.000, 0.000)

    that seems to be converging. can you run a g29 now and post the picture



  • @Veti said in First Layer and Extrusion Problems:

    @fcwilt said in First Layer and Extrusion Problems:

    Do you lead screws really have pitch of 1.25?

    he has z400. where did you see 1.25 leadscrew?
    M92 X160.00 Y160.00 Z400.00 E830.00 ; set steps per mm

    See his bed.g file.

    He has two P parameters for each G30. Not sure if that is messing things up or not.

    Frederick



  • @fcwilt

    good catch.
    yes the second P1.25 parameter should be removed. this is not a valid parameter for G30
    your pitch is 8mm btw.



  • @Veti said in First Layer and Extrusion Problems:

    your pitch is 8mm btw.

    How can we be sure the pitch is 8mm? The config values might be wrong. Maybe the comment in bed.g is correct?

    Clarification is needed from the OP.

    Frederick



  • ok ,i have changed it.

    is it possible to create a homez.g file where it automatically probes the bed on three points and enable compensation ?

    perhaps like :

    ; homez.g
    ; called to home the Z axis
    ;
    ; generated by RepRapFirmware Configuration Tool v3.1.7 on Wed Nov 18 2020 18:04:17 GMT+0100 (Mitteleuropäische Normalzeit)

    G91 ; relative positioning
    G1 H2 Z5 F6000 ; lift Z relative to current position
    G90 ; absolute positioning
    G1 X240 Y220 F6000 ; go to first probe point
    G32 ; home Z by True bed leveling 3 points in bed.g

    or do i have to include the three positions like

    G91 ; relative positioning
    G1 H2 Z5 F6000 ; lift Z relative to current position
    G90 ; absolute positioning
    G1 X240 Y220 F6000 ; go to first probe point
    G30 P0 X330 Y240 Z-9999 ; Front Left
    G30 P1 X150 Y0 Z-9999 ; Middle Back
    G30 P2 X0 Y248 Z-9999 S3 ; Front Right and compensate 3mm



  • @Frederik

    create a macro that calls G28 and G32



  • @fcwilt said in First Layer and Extrusion Problems:

    How can we be sure the pitch is 8mm?

    i cant, but there is a very high chance that isnt a M8 metric lead screw.



  • @Frederik said in First Layer and Extrusion Problems:

    is it possible to create a homez.g file where it automatically probes the bed on three points and enable compensation ?

    Yes.

    But let's get some terminology straight - bed leveling is not homing.

    Bed leveling does what the term suggests - it tries to level the bed.

    Homing is the process of determining that an axis has moved to some known position "telling" the firmware where the hardware actually is.

    Generally you need to:

    • home Z using G28 Z
    • level the bed using G32 and a correctly created bed.g file
    • set the Z=0 datum using a single G30 and the correct position for the probe point
    • load the height map (if you have created one) using G29 S1


  • @Veti said in First Layer and Extrusion Problems:

    @fcwilt said in First Layer and Extrusion Problems:

    How can we be sure the pitch is 8mm?

    i cant, but there is a very high chance that isnt a M8 metric lead screw.

    Agreed given the 8mm is a common value.

    Frederick



  • @fcwilt

    but you are right.

    @Frederik there are several things you have been asked that you have not given an answer to.



  • @fcwilt you are right it was a wrong setting from yesterday. its a normal tr8 4 stop with 8 Lead Spindle



  • i had to test your tips one after the other.... now my z offset is working as it should.


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