Nozzle starts too high when I slice with Cura

[sprt8400 1]

Hello all,

 

I'm hoping you can help me, i have a prusa i3 V2 printer and have used Repetier for a long time. I want to start using Cura and have everything communicating correctly. I leveled my bed and when I home Z it's adjusted perfectly with a pc of paper. However when I slice my model and start printing the nozzle is about 1mm away from the bed. Attached is my gcode for a simple 20x20 cube. Can someone offer insight? 

 

PS I tried both Marlin and Repetier in terms of the G-Code flavor and get the same results.

 

 

PI3MK2_10mm.gcode

[Job_van_gennip 23]

Hi sprt8400,

 

Have you selected the prusa as a machine in Cura?

 

Kind regards,

Job van Gennip

[sprt8400 1]

yes i have prusa as the printer type

[sprt8400 1]

I also tried reprap g-code flavor with no avail. I don't understand why the printer extruder height is correct when I home Z and yet the printer starts printing way too high to even adhere to the bed. 

[Job_van_gennip 23]

I do not see anything weird in the gcode either. I would double check if you have the right machine selected in cura (maybe reinstal it even) did you use your own profile or the basic cura profile? do you have the newest firmware. Those are the only other things i can think of. 

[gr5 2,069]

G28 W ; home all without mesh bed level
G80 ; mesh bed leveling

These lines are prusa specific and I'm not sure if they are correct.  The rest is fine.

Assuming you print through USB:

1) If you print the exact same gcode file through repetier does it print fine?

2) If you slice with repetier and print with cura does it print fine?

Assuming you print through SD card:

3) Please post the first 40 lines of gcode from a repetier slicing of any stl file.

[sprt8400 1]

I sliced with simplify3D and printed with Cura and it worked. I'm not sure what cuts is going to make the print head start at the wrong height

[gr5 2,069]

Oh!  Good.  So the problem is with probably those 2 lines of gcode I posted.  What do the first 40 lines of gcode look like from repetier?

 

I can't tell you what is wrong with the above commands as I don't know Prusa.  You could also try asking on the Prusa forum.  Or just post the first 40 gcodes from both repetier and cura so we can see the difference.

[sprt8400 1]

Below are both scripts with the first 40 lines of gcode created with simplify3d and cura (same model)

 

Done with Cura

;FLAVOR:Marlin
;TIME:456
;Filament used: 0.239059m
;Layer height: 0.15
;MINX:115.6
;MINY:95.6
;MINZ:0.2
;MAXX:134.4
;MAXY:114.4
;MAXZ:9.95
;Generated with Cura_SteamEngine 4.5.0
M82 ;absolute extrusion mode
G21 ; set units to millimeters
G90 ; use absolute positioning
M82 ; absolute extrusion mode
M104 S245.0 ; set extruder temp
M140 S80.0 ; set bed temp
M190 S80.0 ; wait for bed temp
M109 S245.0 ; wait for extruder temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
G92 E0.0 ; reset extruder distance position
G1 Y-3.0 F1000.0 ; go outside print area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E21.5 F1000.0 ; intro line
G92 E0.0 ; reset extruder distance position
G92 E0
G92 E0
G1 F1200 E-3
;LAYER_COUNT:66
;LAYER:0
M107
G0 F3600 X116.61 Y97.216 Z0.2
;TYPE:SKIRT
G1 F1200 E0
G1 F1800 X117.016 Y96.784 E0.01972
G1 X117.477 Y96.411 E0.03944

 

Done with Simply3D

; G-Code generated by Simplify3D(R) Version 4.1.2
; Mar 17, 2020 at 4:49:50 PM
; Settings Summary
;   processName,PETG
;   applyToModels,10mm
;   profileName,Prusa Research Original Prusa i3 MK3 (modified)
;   profileVersion,2018-01-19 08:00:00
;   baseProfile,
;   printMaterial,PLA
;   printQuality,Medium
;   printExtruders,
;   extruderName,Primary Extruder
;   extruderToolheadNumber,0
;   extruderDiameter,0.4
;   extruderAutoWidth,1
;   extruderWidth,0.48
;   extrusionMultiplier,0.9
;   extruderUseRetract,1
;   extruderRetractionDistance,1.5
;   extruderExtraRestartDistance,0
;   extruderRetractionZLift,0
;   extruderRetractionSpeed,1800
;   extruderUseCoasting,1
;   extruderCoastingDistance,0.2
;   extruderUseWipe,1
;   extruderWipeDistance,2
;   primaryExtruder,0
;   layerHeight,0.3
;   topSolidLayers,3
;   bottomSolidLayers,3
;   perimeterOutlines,2
;   printPerimetersInsideOut,1
;   startPointOption,2
;   startPointOriginX,0
;   startPointOriginY,0
;   sequentialIslands,0
;   spiralVaseMode,0
;   firstLayerHeightPercentage,105
;   firstLayerWidthPercentage,115
;   firstLayerUnderspeed,0.2

G1 X117.984 Y96.103 E0.05917
G1 X118.527 Y95.866 E0.07888
G1 X119.098 Y95.704 E0.09862

[gr5 2,069]

wtf???

 

Okay so those lines that start with semicolon are just comments - they don't do anything for the printer they are more for you to see what settings were used when you look at the gcode file.

 

That makes no sense.  it just starts printing without any step for purging or homing or anything.   It doesn't set bed temp, it doesn't set nozzle temp, it doesn't turn on the fan.  This works?  Okay well you need to talk to someone who knows prusa printers.

 

Well try this - delete everything in the cura gcode file up to and including that M107 and see if it prints okay.  That will tell us something.

[gr5 2,069]

I still think the problem is related to one of those 2 gcodes I highlighted.

[sprt8400 1]

oops heres the gcode without the semicolons

 

Cura

M82 ;absolute extrusion mode
G21 ; set units to millimeters
G90 ; use absolute positioning
M82 ; absolute extrusion mode
M104 S245.0 ; set extruder temp
M140 S80.0 ; set bed temp
M190 S80.0 ; wait for bed temp
M109 S245.0 ; wait for extruder temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
G92 E0.0 ; reset extruder distance position
G1 Y-3.0 F1000.0 ; go outside print area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E21.5 F1000.0 ; intro line
G92 E0.0 ; reset extruder distance position
G92 E0
G92 E0
G1 F1200 E-3
;LAYER_COUNT:66
;LAYER:0
M107
G0 F3600 X116.61 Y97.216 Z0.2
;TYPE:SKIRT
G1 F1200 E0
G1 F1800 X117.016 Y96.784 E0.01972
G1 X117.477 Y96.411 E0.03944
G1 X117.984 Y96.103 E0.05917
G1 X118.527 Y95.866 E0.07888
G1 X119.098 Y95.704 E0.09862

 

Simplify3d

G90
M83
M106 S0
M140 S80
M190 S80
M104 S245 T0
M109 S245 T0
M115 U3.0.7 ; use the latest firmware version
G28 W ; home all axes without mesh bed leveling
G80 ; run mesh bed leveling routine
G1 Y-3.0 F1000.0 ; prepare to prime
G92 E0 ; reset extrusion distance
G1 X60.0 E9.0  F1000.0 ; priming
G1 X100.0 E12.5  F1000.0 ; priming
; process PETG
; layer 1, Z = 0.065
T0
G1 E-1.5000 F1800
; feature skirt
; tool H0.315 W0.552
G1 Z0.065 F800
G1 X92.724 Y94.057 F5000
G1 E1.5000 F1800
G1 X94.057 Y92.724 E0.1227 F720
G1 X105.943 Y92.724 E0.7733
G1 X107.276 Y94.057 E0.1227
G1 X107.276 Y105.943 E0.7733
G1 X105.943 Y107.276 E0.1227
G1 X94.057 Y107.276 E0.7733
G1 X92.724 Y105.943 E0.1227
G1 X92.724 Y94.057 E0.7733
G1 E-1.5000 F1800
; feature inner perimeter
G1 X95.828 Y95.828 F5000
G1 E1.5000 F1800
G1 X104.172 Y95.828 E0.5429 F648
G1 X104.172 Y104.172 E0.5429
G1 X95.828 Y104.172 E0.5429
G1 X95.828 Y96.028 E0.5299
G1 X95.828 Y95.828 F648
; feature outer perimeter
G1 X95.276 Y95.276 F5000
G1 X104.724 Y95.276 E0.6147 F576
G1 X104.724 Y104.724 E0.6147
G1 X95.276 Y104.724 E0.6147
G1 X95.276 Y95.476 E0.6017
G1 X95.

[gr5 2,069]

You should probably talk to prusa experts.  Anyway here are some possibilities:

1) The M115 - I've never seen that before.  That might change the functionality of the M28 command that follows it.  I'd try copying this to just above the G28 W line.  Note that G28 is where it homes the Z (and other axes).

M115 U3.0.7 ; use the latest firmware version

2) T0 - This chooses tool zero or in other words your primary extruder.  This isn't normally necessary for a single extruder machine.  But this can sometimes alter the Z height due to offsets in the printer for different extruder nozzles.  It sounds crazy for a single extruding machine but try it.  Put the T0 right after the M107.

 

3) Z speed.  I notice that S3D lowers the speed to F800 - that's in mm/minute so divide by 60 to get mm/sec which is 13.33mm/sec.  Cura sets it to 60mm/sec in this line:

G0 F3600 X116.61 Y97.216 Z0.2

It's normally moving X and Y much farther than Z but if the head was already near X116 and Y97 then it's trying to move the Z faster than you would expect is possible (although really the firmware in the prusa should also limit the Z but maybe it's set too high or maybe there's a bug in the prusa firmware and it's not limiting the Z speed on compound moves like this  - you'd be amazed how many bugs are in there).  So I'd try lowering that F3600 to F800 to match S3D for that opening move.

 

I'm not saying you should *always* edit your gcodes direclty - this is just the first step to figure out what is different between the slicers - once we know the problem we can fix it in cura settings.

[sprt8400 1]

I think I'll stick to Simplify3d, I made the changes you advised and still no avail.... The only problem with Simplify is it can have finicky slices, where a wall will print perfectly with one model and not another. Perhaps these could be some of the model designs as well? 

[gr5 2,069]

Like cura, I think S3D has something like "print thin walls" or something similar that you have to enable.