Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+

[juliann]

Thank you @fcwilt

All slicer configurations were created based on findings that I came across on forums and Internet, I mean, they are there just by doing copy and paste...

Where should I start fixing or organising it?

[fcwilt]

@juliann said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

Thank you @fcwilt

All slicer configurations were created based on findings that I came across on forums and Internet, I mean, they are there just by doing copy and paste...

Where should I start fixing or organising it?

I'm about to have lunch. So give me a bit of time and I will create some basic code you can put into the slicer as a starting point.

Frederick

[juliann]

@fcwilt

Thank you so much Frederick for taking the time, please enjoy your lunch

[fcwilt]

@juliann said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

@fcwilt

Thank you so much Frederick for taking the time, please enjoy your lunch

There has been a bit of disruption of my work as the local authorities have been out and about near my home looking for a missing person. They asked if I would review my security camera recordings to see if anything was picked up.

They are gone now and I am back to work.

Sorry for the delay.

Frederick

[fcwilt]

@juliann said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

@fcwilt

Thank you so much Frederick for taking the time, please enjoy your lunch

I installed SuperSlicer and had it slice a simple cube object so I could set what code it generated with default settings.

I have posted the code below with all generated "junk" removed.

; SuperSlicer print start code using RepRap setting

M140 S60    ; set bed temperature
G10 P0 R190 ; sets the standby temperature
G10 P0 S190 ; set temperature
G28         ; home all axes
G1 Z5 F5000 ; lift nozzle *** THE POSITIONING MODE (absolute or relative) IS NOT KNOWN ***
M107        ; disable fan
G21         ; set units to millimeters
G90         ; use absolute coordinates
M83         ; use relative distances for extrusion
G10 P0 S190 ; set temperature
M116        ; wait for temperature to be reached
M190 S60    ; set bed temperature and wait for it to be reached
M107        ; disable fan

; SuperSlicer print end code using RepRap setting

M486 S-1 ; object cancelation
M107     ; disable fan
M104 S0  ; turn off temperature
G28 X0   ; home X axis
M84      ; disable motors

With the updated homeall.g file I posted earlier this SuperSlicer generated code is basically OK and should work - although it does have a a minor flaw or two.

So I would update your homeall.g file and make sure it works.

Then slice a simple file and see if the start/end code matches what I posted here.

If it does try to print with it.

Frederick

[juliann]

Hi Frederick @fcwilt

No problem at all, thanks again for taking all this time helping me.

I am checking and updating all the settings following your instructions and I will try another print. I will let you know the results tomorrow for sure.

Thank you very much!
Julián.

[juliann]

@fcwilt

Hi Frederick

Sorry for the delay, but the tests didn't result very well, basically I am getting a similar issues.
Just to re-confirm: have I to remove the previous start/ end code on the slicer?

So the right configuration should be based on a combination between homeall.g and the slicer settings?

Thank you very much
Julián.

[fcwilt]

@juliann said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

@fcwilt

Hi Frederick

Sorry for the delay, but the tests didn't result very well, basically I am getting a similar issues.
Just to re-confirm: have I to remove the previous start/ end code on the slicer?

So the right configuration should be based on a combination between homeall.g and the slicer settings?

Thank you very much
Julián.

Aside from the homeall.g file I posted the other code was generated by SuperSlicer. I posted here as it was other than removing lines that were just comments.

The file you are trying to print should have code that looked like what I posted.

Please post as before up until "layer 1" starts.

Thanks.

Frederick

[sinned6915]

@juliann you have too many balls in the air. rule one of diganostics and trouble shooting is simplify.

1. from your your bedmap, i suspect that your rails are not in alignment- i think that your back right (Xmax,Ymax) rail is HIGH. It appears high in the map because the Z is inverted. re-read the v-core docs on rail alignment and see if its right. if we know that its off, we can take that into account.

2. In your start gode, you are settin z-o, then adjusting the nozzle -0.12mm realtive, then mesh the bed?? what is the purpose of that?
   M290 R0 S-0.12
   in the fragment of what you were printing, you had a standby temp of 265 and print temp of 267. What are you printing with?

3. Consider tramming you bed with 4 points, not 3. save your beg.g and make a SIMPLER one. you have to crawl before you can run. once you see this works, then go back and add in the iteration stuff if yo want it. i dont think you do if you have a quality bed that is made well.
   bed.g-

M290 R0 S0    ;  clear baby stepping
M561               ;  reset all bed adjustments
M400               ;  flush move queue

if !move.axes[0].homed or !move.axes[1].homed or !move.axes[2].homed
  echo "not all axes homed, homing axes first"
  G28

G30 X250 Y250                               ; set middle of bed

G30 P0 X10 Y10 Z-99999              ; Front Left
G30 P1 X10 Y470 Z -9999             ; BL
G30 P2 X460 Y470 Z-99999         ; BR
G30 P3 X460 Y10 Z-99999 S3      ; FR autolevel 3 screws 

G30 X250 Y250                              ; reprobe middle of bed in case it shifted

4. prove to yourself that it level - move Z to a height you can check you nozzle with a feeler gauge of some kind. paper, cardboard, anything. jog the nozzle till you can just feel it dragging on the feeler and move the head around. you can use a M18 X Y to disable the steppers but keep power to the Z motors.

5. print something WITHOUT the heightmap, only bed tram. this want to be like 4 squares, 1 layer thick, 50x50 x0.3mm high, one at each corner and one in the middle.

6. Aftter you print something w/o heightmap, THEN perform a height map and reprint.

7. if you want to slice a simple cube in superslicer and save the config bundle, you should be able to zip it and attach to this thread. those of us who use super slicer can open it and see exactly what is in there for gcodes and settings.

sinneD

[juliann]

Hi Frederick & sinneD & @T3P3Tony @fcwilt @sinned6915

Sorry for the delay in my response.

I rechecked everything in my printer included mechanical and the frame assembly as well.
Everything seems to be fine, no issues found.

Frederick @fcwilt
I did several tests following your instructions but I am afraid the behaviour is always de same I described before:

• The printer is already calibrated and all previous prints were perfectly fine.
• Power off and power on the printer.
• I try to print anything and the first layer is much more closer to the bed that usual.
• Cancel that print (Emergency stop on DWC) and clean the bed
• Then I print again the same file without touching any setting and now the first layer is perfect again.... (and of course I can continue printing without issues).

I am attaching "30 mm cube.gcode " file.

@sinned6915
Thank you very much for taking the time analysing my problem. Please see below my answers

1. After rechecking the frame, belts, carriage many times I can confirm you that there is no problem there.
   Just to clarify, I think the issue I am experiencing is not precisely what you are suggesting, please see the behaviour I mentioned before.
   I mean, I am able to get perfectly fine prints, first layer included but always considering the behaviour/ issue I previously described.

2. To be honest, it is probably inexperience from my side :-)... I am still new in 3d printing and many of my settings are there just for someone's advice.
   If you know a better way to do that I will appreciate if you share it with me.
   I am printing PETG-CF, that temp is working very well to me.

3. Done! thanks so much for this, it seems to be better now.

4. I did that but the results are conditioned by the behaviour I described before.
   After powering on the printer the nozzle is very close to the bed, so if I do this test I probably scratch the bed.
   but...
   if I press emergency stop then the test result is perfectly fine (and of course any print I do)

5. I did it, same results as response 4.

6. Pressing emergency stop after powering on and then printing w/o heightmap I got the expected results based on the height map showed in DWC.
   If I don't press the emergency stop after power on, the nozzle is too close to the bed (with or without heightmap).
   If press emergency stop and then I print with the heightmap the print is perfectly fine.

7. SuperSlicer_config_bundle.ini & 30 mm cube.gcode

[print:JEN 0.4 PETG Filamentive Carbon F]
allow_empty_layers = 0
avoid_crossing_not_first_layer = 1
avoid_crossing_perimeters = 1
avoid_crossing_perimeters_max_detour = 0
bottom_fill_pattern = rectilinear
bottom_solid_layers = 6
bottom_solid_min_thickness = 0
bridge_acceleration = 0
bridge_angle = 0
bridge_flow_ratio = 60%
bridge_overlap = 145%
bridge_speed = 15
bridge_speed_internal = 15
bridged_infill_margin = 200%
brim_ears = 0
brim_ears_detection_length = 1
brim_ears_max_angle = 125
brim_ears_pattern = concentric
brim_inside_holes = 0
brim_offset = 0
brim_width = 0
brim_width_interior = 0
clip_multipart_objects = 0
compatible_printers = 
compatible_printers_condition = 
complete_objects = 1
complete_objects_one_brim = 0
complete_objects_one_skirt = 1
complete_objects_sort = object
curve_smoothing_angle_concave = 0
curve_smoothing_angle_convex = 0
curve_smoothing_cutoff_dist = 2
curve_smoothing_precision = 0
default_acceleration = 0
dont_support_bridges = 1
draft_shield = 0
duplicate_distance = 6
enforce_full_fill_volume = 1
ensure_vertical_shell_thickness = 0
exact_last_layer_height = 0
external_infill_margin = 150%
external_perimeter_cut_corners = 0%
external_perimeter_extrusion_spacing = 
external_perimeter_extrusion_width = 0.45
external_perimeter_overlap = 100%
external_perimeter_speed = 50%
external_perimeters_first = 0
external_perimeters_hole = 1
external_perimeters_nothole = 1
external_perimeters_vase = 0
extra_perimeters = 1
extra_perimeters_odd_layers = 0
extra_perimeters_overhangs = 0
extruder_clearance_height = 20
extruder_clearance_radius = 20
extrusion_spacing = 
extrusion_width = 0.45
fill_angle = 45
fill_angle_increment = 0
fill_density = 0%
fill_pattern = gyroid
fill_smooth_distribution = 10%
fill_smooth_width = 50%
fill_top_flow_ratio = 125%
first_layer_acceleration = 0
first_layer_extrusion_spacing = 
first_layer_extrusion_width = 0.42
first_layer_flow_ratio = 100%
first_layer_height = 0.25
first_layer_infill_speed = 15
first_layer_min_speed = 0
first_layer_size_compensation = -0.2
first_layer_size_compensation_layers = 1
first_layer_speed = 10
gap_fill = 1
gap_fill_last = 1
gap_fill_min_area = 25%
gap_fill_overlap = 100%
gap_fill_speed = 20
gcode_comments = 0
gcode_label_objects = 0
hole_size_compensation = 0
hole_size_threshold = 100
hole_to_polyhole = 0
hole_to_polyhole_threshold = 0.01
hole_to_polyhole_twisted = 1
infill_acceleration = 0
infill_anchor = 600%
infill_anchor_max = 50
infill_connection = connected
infill_connection_bottom = connected
infill_connection_solid = connected
infill_connection_top = connected
infill_dense = 1
infill_dense_algo = enlarged
infill_every_layers = 1
infill_extruder = 1
infill_extrusion_spacing = 
infill_extrusion_width = 0.42
infill_first = 0
infill_only_where_needed = 0
infill_overlap = 35%
infill_speed = 20
inherits = 
interface_shells = 0
ironing = 0
ironing_angle = -1
ironing_flowrate = 15%
ironing_spacing = 0.1
ironing_speed = 15
ironing_type = top
layer_height = 0.2
max_print_speed = 20
max_volumetric_speed = 0
milling_after_z = 200%
milling_extra_size = 150%
milling_post_process = 0
milling_speed = 30
min_skirt_length = 20
min_width_top_surface = 100%
model_precision = 0.0001
no_perimeter_unsupported_algo = none
notes = 
only_one_perimeter_first_layer = 0
only_one_perimeter_top = 1
only_one_perimeter_top_other_algo = 0
only_retract_when_crossing_perimeters = 1
ooze_prevention = 0
output_filename_format = [input_filename_base].gcode
over_bridge_flow_ratio = 125%
overhangs_reverse = 0
overhangs_reverse_threshold = 250%
overhangs_speed = 10
overhangs_width = 50%
overhangs_width_speed = 1%
perimeter_acceleration = 0
perimeter_bonding = 0%
perimeter_extruder = 1
perimeter_extrusion_spacing = 
perimeter_extrusion_width = 0.45
perimeter_loop = 0
perimeter_loop_seam = rear
perimeter_overlap = 100%
perimeter_round_corners = 0
perimeter_speed = 20
perimeters = 3
post_process = 
print_extrusion_multiplier = 100%
print_retract_length = -1
print_retract_lift = -1
print_settings_id = 
print_temperature = 0
raft_layers = 0
resolution = 0.002
seam_angle_cost = 100%
seam_position = aligned
seam_travel_cost = 100%
single_extruder_multi_material_priming = 1
skirt_brim = 0
skirt_distance = 3
skirt_distance_from_brim = 1
skirt_extrusion_width = 0
skirt_height = 1
skirts = 2
slice_closing_radius = 0.049
small_perimeter_max_length = 20
small_perimeter_min_length = 10
small_perimeter_speed = 15
solid_fill_pattern = rectilineargapfill
solid_infill_below_area = 70
solid_infill_every_layers = 0
solid_infill_extruder = 1
solid_infill_extrusion_spacing = 
solid_infill_extrusion_width = 0.42
solid_infill_speed = 20
solid_over_perimeters = 2
spiral_vase = 0
standby_temperature_delta = -5
support_material = 0
support_material_angle = 0
support_material_auto = 1
support_material_buildplate_only = 1
support_material_contact_distance_bottom = 0.2
support_material_contact_distance_top = 0.2
support_material_contact_distance_type = plane
support_material_enforce_layers = 0
support_material_extruder = 1
support_material_extrusion_width = 0.35
support_material_interface_contact_loops = 0
support_material_interface_extruder = 1
support_material_interface_layers = 3
support_material_interface_pattern = rectilinear
support_material_interface_spacing = 0
support_material_interface_speed = 100%
support_material_pattern = rectilinear
support_material_solid_first_layer = 0
support_material_spacing = 2.5
support_material_speed = 15
support_material_synchronize_layers = 0
support_material_threshold = 0
support_material_with_sheath = 1
support_material_xy_spacing = 50%
thin_perimeters = 1
thin_perimeters_all = 0
thin_walls = 0
thin_walls_merge = 1
thin_walls_min_width = 33%
thin_walls_overlap = 50%
thin_walls_speed = 10
threads = 8
top_fill_pattern = monotonic
top_infill_extrusion_spacing = 
top_infill_extrusion_width = 0.4
top_solid_infill_speed = 20
top_solid_layers = 6
top_solid_min_thickness = 0
travel_acceleration = 1500
travel_speed = 300
travel_speed_z = 0
wipe_tower = 0
wipe_tower_bridging = 10
wipe_tower_brim = 150%
wipe_tower_no_sparse_layers = 0
wipe_tower_rotation_angle = 0
wipe_tower_width = 60
wipe_tower_x = 180
wipe_tower_y = 140
xy_inner_size_compensation = 0
xy_size_compensation = 0


[filament:V-CORE 3 Carbon F]
bed_temperature = 80
bridge_fan_speed = 100
bridge_internal_fan_speed = -1
chamber_temperature = 0
compatible_printers = 
compatible_printers_condition = 
compatible_prints = 
compatible_prints_condition = 
cooling = 1
disable_fan_first_layers = 1
end_filament_gcode = ""
external_perimeter_fan_speed = 20
extrusion_multiplier = 0.81
fan_always_on = 0
fan_below_layer_time = 60
filament_colour = #29B2B2
filament_cooling_final_speed = 3.4
filament_cooling_initial_speed = 2.2
filament_cooling_moves = 4
filament_cooling_zone_pause = 0
filament_cost = 0
filament_density = 0
filament_deretract_speed = 50
filament_diameter = 1.75
filament_dip_extraction_speed = 70
filament_dip_insertion_speed = 33
filament_enable_toolchange_part_fan = 0
filament_enable_toolchange_temp = 0
filament_load_time = 0
filament_loading_speed = 28
filament_loading_speed_start = 3
filament_max_overlap = 100%
filament_max_speed = 0
filament_max_volumetric_speed = 0
filament_max_wipe_tower_speed = 0
filament_melt_zone_pause = 0
filament_minimal_purge_on_wipe_tower = 15
filament_notes = ""
filament_ramming_parameters = "120 100 6.6 6.8 7.2 7.6 7.9 8.2 8.7 9.4 9.9 10.0| 0.05 6.6 0.45 6.8 0.95 7.8 1.45 8.3 1.95 9.7 2.45 10 2.95 7.6 3.45 7.6 3.95 7.6 4.45 7.6 4.95 7.6"
filament_retract_before_travel = nil
filament_retract_before_wipe = nil
filament_retract_layer_change = nil
filament_retract_length = 0.3
filament_retract_lift = nil
filament_retract_lift_above = nil
filament_retract_lift_below = nil
filament_retract_restart_extra = nil
filament_retract_speed = 60
filament_seam_gap = nil
filament_settings_id = ""
filament_shrink = 100%
filament_skinnydip_distance = 31
filament_soluble = 0
filament_spool_weight = 0
filament_toolchange_delay = 0
filament_toolchange_part_fan_speed = 50
filament_toolchange_temp = 200
filament_type = PET
filament_unload_time = 0
filament_unloading_speed = 90
filament_unloading_speed_start = 100
filament_use_fast_skinnydip = 0
filament_use_skinnydip = 0
filament_vendor = (Unknown)
filament_wipe = nil
filament_wipe_advanced_pigment = 0.5
filament_wipe_extra_perimeter = nil
filament_wipe_speed = nil
first_layer_bed_temperature = 80
first_layer_temperature = 267
full_fan_speed_layer = 0
inherits = 
max_fan_speed = 15
max_speed_reduction = 90%
min_fan_speed = 15
min_print_speed = 10
slowdown_below_layer_time = 5
start_filament_gcode = "; Filament gcode\nG1 X250 Y250 \nG30\n\nM290 R0 S0.09 \n\nG29 S1\n"
temperature = 262
top_fan_speed = 15


[printer:V-CORE 3 Frederick]
bed_custom_model = 
bed_custom_texture = 
bed_shape = 0x0,500x0,500x500,0x500
before_layer_gcode = ; 0.2mm layer, 8 bands 5mm each, total height 40mm\n;{if layer_num== 1}M572 D0 S0.13\n;{elsif layer_num== 20}M572 D0 S0.14\n;{elsif layer_num== 40}M572 D0 S0.15\n;{elsif layer_num== 60}M572 D0 S0.16\n;{elsif layer_num== 80}M572 D0 S0.17\n;{elsif layer_num== 100}M572 D0 S0.18\n;{elsif layer_num== 120}M572 D0 S0.19\n;{elsif layer_num== 150}M572 D0 S0.20\n;{endif}
between_objects_gcode = 
color_change_gcode = M600
cooling_tube_length = 5
cooling_tube_retraction = 91.5
default_filament_profile = 
default_print_profile = 
deretract_speed = 50
end_gcode = M104 S0 ; turn off temperature\nM140 S0 ; turn off bed\nG28 X0  ; home X axis\nM84     ; disable motors\nM999
extra_loading_move = -2
extruder_colour = ""
extruder_fan_offset = 0%
extruder_offset = 0x0
extruder_temperature_offset = 0
fan_kickstart = 0
fan_percentage = 0
fan_speedup_overhangs = 1
fan_speedup_time = 0
feature_gcode = 
gcode_filename_illegal_char = 
gcode_flavor = reprapfirmware
gcode_precision_e = 5
gcode_precision_xyz = 3
high_current_on_filament_swap = 0
host_type = octoprint
inherits = 
layer_gcode = 
machine_limits_usage = time_estimate_only
machine_max_acceleration_e = 10000,5000
machine_max_acceleration_extruding = 1500,1250
machine_max_acceleration_retracting = 1500,1250
machine_max_acceleration_travel = 1500,1250
machine_max_acceleration_x = 9000,1000
machine_max_acceleration_y = 9000,1000
machine_max_acceleration_z = 500,200
machine_max_feedrate_e = 120,120
machine_max_feedrate_x = 500,200
machine_max_feedrate_y = 500,200
machine_max_feedrate_z = 12,12
machine_max_jerk_e = 2.5,2.5
machine_max_jerk_x = 10,10
machine_max_jerk_y = 10,10
machine_max_jerk_z = 0.2,0.4
machine_min_extruding_rate = 0,0
machine_min_travel_rate = 0,0
max_gcode_per_second = 1500
max_layer_height = 0.3
max_print_height = 200
milling_diameter = 
milling_toolchange_end_gcode = 
milling_toolchange_start_gcode = 
milling_z_lift = 
min_layer_height = 0.07
min_length = 0.035
nozzle_diameter = 0.4
parking_pos_retraction = 92
pause_print_gcode = M601
print_host = 
printer_model = 
printer_notes = 
printer_settings_id = 
printer_technology = FFF
printer_variant = 
printer_vendor = 
printhost_apikey = 
printhost_cafile = 
printhost_port = 
remaining_times = 0
retract_before_travel = 3
retract_before_wipe = 0%
retract_layer_change = 0
retract_length = 0.3
retract_length_toolchange = 10
retract_lift = 0
retract_lift_above = 0.3
retract_lift_below = 0
retract_lift_first_layer = 0
retract_lift_top = "All surfaces"
retract_restart_extra = 0
retract_restart_extra_toolchange = 0
retract_speed = 60
seam_gap = 15%
silent_mode = 1
single_extruder_multi_material = 0
start_gcode = G28 ; home all axes\nG1 Z5 F5000 ; lift nozzle\n
start_gcode_manual = 0
template_custom_gcode = 
thumbnails = 0x0,0x0
thumbnails_color = #018aff
thumbnails_custom_color = 0
thumbnails_with_bed = 1
time_estimation_compensation = 100%
tool_name = 0
toolchange_gcode = 
use_firmware_retraction = 0
use_relative_e_distances = 0
use_volumetric_e = 0
variable_layer_height = 1
wipe = 0
wipe_advanced = 0
wipe_advanced_algo = linear
wipe_advanced_multiplier = 60
wipe_advanced_nozzle_melted_volume = 120
wipe_extra_perimeter = 0
wipe_speed = 0
z_offset = 0
z_step = 0.005

[physical_printer:Printer 1]
host_type = duet
preset_name = VCoreNeu - PrusaSlicer_config_bundle.ini
print_host = duet.fritz.box
printer_technology = FFF
printhost_apikey = vcore2019
printhost_authorization_type = key
printhost_cafile = 
printhost_password = 
printhost_port = 
printhost_user = 

[presets]
print = JEN 0.4 PETG Filamentive Carbon F
sla_print = - default -
sla_material = - default -
printer = V-CORE 3 F
filament = V-CORE 3 Carbon F
physical_printer = 

Thank you very much!
Julián.

[fcwilt]

@juliann

Hi,

I will take a look at the file but the situation you are describing still seems to me like something "corrects" the configuration during the first print, but doesn't affect the first print, but does cause the second print to be ok.

Frederick

[fcwilt]

@juliann

I have noticed something odd.

I gave you a very simple, edited version of the homeall.g file you first posted.

I did not cancel baby-stepping in the code I posted for you.

Homing does not cancel baby-stepping unless the homing code has the command to do that.

In your example print file you have this:

G1 X250 Y250           ; move to the XY reference point for G30
G30                    ; set the Z-0 Datum
M290 R0 S0.09          ; set baby-stepping

So the first print after power up sets baby-stepping (from 0.00 to 0.09) but it does so after the G30.

For the next print I am thinking baby-stepping is still in effect (it remains at 0.09) which changes the results of G30 and the nozzle ends up farther away from the bed on the next print(s).

And that is consistent with what you are reporting.

Normally you don't want to set baby-stepping in a print file. To fix first layer Z issues you would adjust the Z Trigger Height parameter in G31 which would cause the G30 to set things so the Z position is correct for printing the first layer.

Remove the M290 from your print code and adjust the Z Trigger Height parameter in G31 to get the Z height correct.

If I had put M290 R0 S0 in the homeall code I posted you wouldn't be seeing this issue - my bad - all attempts to print would have been too close to the bed.

Frederick

[fcwilt]

@juliann

Add these two lines at the beginning of your homeALL.g file and your homeZ.g file:

G29 S2                           ; cancel mesh bed compensation
M290 R0 S0                       ; cancel baby stepping

Frederick

[juliann]

@fcwilt

Hi Frederick! @fcwilt

Very good news, you found the solution!
I applied your suggestions and now the issue is totally fixed!

Thank you so much for all the help provided.

Julián.

[fcwilt]

@juliann said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

@fcwilt

Hi Frederick! @fcwilt

Very good news, you found the solution!
I applied your suggestions and now the issue is totally fixed!

Thank you so much for all the help provided.

Julián.

Glad we were able to sort things out.

Frederick

[dc42]

@fcwilt said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

For the next print I am thinking baby-stepping is still in effect (it remains at 0.09) which changes the results of G30 and the nozzle ends up farther away from the bed on the next print(s).

Thanks for identifying this. It sounds as though babystepping is affecting the behaviour of G29 and G30 probing, and I think it would be better if it didn't. I will add this to the work list.

[dc42]

Looks like G30 is working correctly after all. If I run G30 to establish Z=0, send M290 Z1 and then G1 Z0, the nozzle sits 1mm above the bed. If I then run G30 again and then again send G1 Z0, the nozzle is still 1mm above the bed.

[fcwilt]

@dc42 said in Unreliable Z height calibration on V-Core 3 w/BLtouch & Mini 5+:

Looks like G30 is working correctly after all. If I run G30 to establish Z=0, send M290 Z1 and then G1 Z0, the nozzle sits 1mm above the bed. If I then run G30 again and then again send G1 Z0, the nozzle is still 1mm above the bed.

Well it seems my understanding of the interaction of M290 and G30 was wrong.

But it seemed to explain what the OP was seeing and the suggested changes did fix the problem.

Which then leaves the original question as to why the first print never worked but subsequent ones did.

Frederick

[PCR]

@dc42 Same here. Babystepping and G30 works.

[Nurgelrot]

@juliann Just a note about your config unrelated to the Z problem. Don't you have your current too high for the motor on the LGX extruder? Max current should only be 0.7A. Building the same printer as you (using a SuperPINDA vs BLtouch) and comparing configs