Issue with Extruder Height in Recent Cura Gcodes

[mohsengh 0]

Hi everyone,

I am currently using an extrusion/DIW-based 3D printer (F-NIS 23151, Sygnis, Version C) and generating my G-code files with Cura Ultimaker. Recently, I've encountered an issue with the G-codes created in Cura.

At the start of the print, for the first 2-3 minutes, the extruder moves up and begins printing approximately 3 cm above the print bed. This happens despite having set the initial nozzle-to-bed distance to 0.1 mm. After about 2-4 minutes, the extruder corrects itself, and the nozzle height becomes accurate, printing with the correct 0.1 mm distance from the bed.

Interestingly, this issue only occurs with the G-codes generated in the last two weeks. Older G-codes work perfectly without this problem.

It is also worth noting that to make generated gcodes in Cura readable by my 3D printer, I need to post process these gcodes via a software provided by the supplier, F-NIS postprocessor (see attached photos).

Could you please help me troubleshoot this issue and guide me on how to fix it?

Thank you in advance for your assistance!

Grid-25%-CYL1-33mmD-15H_processed.gcode Gyroid-20%-cube 2by1cm_processed.gcode

[Slashee_the_Cow 438]

Could you provide an example of one (or both) of those gcode files straight out of Cura, before processing it through F-NIS? The problem is right at the start of the first layer (from the "grid" file):

;LAYER_COUNT:50
;LAYER:0
M107
G0 X99.29 Y65.04 Z0.28 F3000
;TYPE:SKIRT
M126 F
G1 Z24.98 F3000
G1 X100.41 Y63.46

It moves to what would be a normal starting position, then opens a valve (at least that's what M126 is for usually, how your printer controls extrusion? Because none of the movement commands include extruder position) and immediately moves to 24.98mm from the build plate and tries to print the first layer. It corrects that at the end of the layer where it positions itself to start the next layer:

M127 F
G0 X115.20 Y91.07 F3000
G0 X115.12 Y89.63
;MESH:NONMESH
G0 X115.12 Y89.63 Z0.58 F600
G0 X104.12 Y64.14 F3000
G0 X103.87 Y63.87
;TIME_ELAPSED:142.131971
;LAYER:1

The "gyroid cube" file does the same thing except it only moves up to Z19.9mm

[mohsengh 0]

Hi Slashee_the_Cow,

 

Many thanks for your explanations. 

I attached the generated G-codes without post processing.

I would be so grateful if you could tell me how can I fix the problem?

 

Once again thanks.

Grid-25%-CYL1-33mmD-15H.gcode Gyroid-20%-cube 2by1cm.gcode

[Slashee_the_Cow 438]

The problem lines aren't in the Cura output, so they must be being added by F-NIS.

 

It might be a bit of a hassle, but you just need to go into the gcode files after they've been processed and remove a single line. Right near the top (this is from the gyroid cube processed gcode):

;LAYER_COUNT:33
;LAYER:0
M107
G0 X103.20 Y63.95 Z0.30 F3600
;TYPE:SKIRT
M126 F
G1 Z19.90 F3000
G1 X103.40 Y63.65
G1 X103.40 Y63.65 F450
G1 X103.80 Y63.29
G1 X104.02 Y63.16
G1 X104.49 Y62.96
G1 X104.81 Y62.90
G1 X125.00 Y62.90

 

That G1 line with a Z coordinate - delete that line and save the file. Same for the grid processed file:

;LAYER_COUNT:50
;LAYER:0
M107
G0 X99.29 Y65.04 Z0.28 F3000
;TYPE:SKIRT
M126 F
G1 Z24.98 F3000
G1 X100.41 Y63.46
G1 X100.41 Y63.46 F300
G1 X101.76 Y61.94
G1 X103.22 Y60.61
G1 X104.67 Y59.54
G1 X106.53 Y58.45

 

So the result (for the grid) would be this:

;LAYER_COUNT:50
;LAYER:0
M107
G0 X99.29 Y65.04 Z0.28 F3000
;TYPE:SKIRT
M126 F
G1 X100.41 Y63.46
G1 X100.41 Y63.46 F300
G1 X101.76 Y61.94
G1 X103.22 Y60.61
G1 X104.67 Y59.54
G1 X106.53 Y58.45
G1 X108.25 Y57.67
G1 X110.17 Y57.04

[mohsengh 0]

@Slashee_the_Cow

Hi

 

Many thanks for your valuable explanations. That was very helpful and I could solve the problem.

 

Warmest wishes,

Mohsen