Nozzle scratches over print after tool change
 
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Koet
 Koet
(@koet)
Member
Nozzle scratches over print after tool change

Hi,

I recently tried to print multicolor with my MK4s single extruder printer. I created several extruders in the slicer and then assigned the extruders to the respective areas of the model. The printing and the filament changes basically worked. However, before the extruder moved to the purge tower after the filament change, it first moved to his last position (almost the exact opposite side of the print) and then scratched the print with the nozzle on its way to the purge tower. This was clearly audible and the nozzle left a scratch on the print surface. After that, printing continued without any problems, but the same problem occurred after the next color change (after which I stopped printing).Does anyone have any idea what I need to set in the slicer or in the custom G-code so that the printer has the correct height before moving to the purge tower?

In the color change G-code field it says

M600
G1 E0.3 F1500

and the G-Code around the tool change is listed below. Does anybody have any idea why the printer "forgets" to lift the nozzle?
Thanks a lot!

M204 P4000
;HEIGHT:0.2
;TYPE:Wipe tower
;WIDTH:0.5
;--------------------
; CP TOOLCHANGE START
; toolchange #1
; material : PLA -> PLA
;--------------------
M220 B
M220 S100
; CP TOOLCHANGE UNLOAD
;WIDTH:1
;WIDTH:0.5
G4 S0
M486 S-1
; Filament-specific end gcode
M600
T1
M572 S0.036 ; Filament gcode

M142 S36 ; set heatbreak target temp

G1 X231.583 Y180.424 F18000
G1 X231.083 Y179.124
G1 Z.2 F720
G4 S0
G1 Y179.624
; CP TOOLCHANGE WIPE
;WIDTH:1.25
G1 X172.083 E5.6059 F792
G1 X173.958 Y178.374 E0.2141
G1 X231.583 E5.4753 F900
;WIDTH:0.5
M220 R
G1 F18000
G4 S0
G92 E0
; CP TOOLCHANGE END
;------------------
Posted : 01/01/2025 4:39 pm
Xargas
(@xargas)
Active Member
RE:

If you are using MK4S + MMU with PrusaSlicer 2.9.0 and current profiles, you should not need any change in the custom GCODE sections.

- Are you trying to do a multicolor print using MK4S only (without MMU), but using some special settings for a wipe tower?

- Can you upload your 3mf file (zipped) so we can have a look at your settings?

 

When I create a MK4S + MMU print, the material change lifts the Z axis after "M204 P4000" and "M220 B":

When I use a MK4S profile without MMU, I get something similar to your output:

 

So I assume that this is the location to change some settings -> When the latter is your use case, I suspect that you need to activate this setting on your "Printers" tab:

then you get the Z axis lift code generated.

 

 

This post was modified 4 days ago by Xargas
Posted : 15/01/2025 9:27 pm
Xargas
(@xargas)
Active Member
RE: Nozzle scratches over print after tool change

This thread might also help: https://forum.prusa3d.com/forum/prusaslicer/manual-multicolor/paged/8/

 

Posted : 15/01/2025 9:33 pm
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