Nozzle temp increase midway through print

[lenp49 0]

I have been trying to get rid of my stringing issues and have played with all the recommended settings in Cura with little or no improvement.  Watching the print (retraction towers) I notice the nozzle temp increased about one third the way through the print - right where the stringing began!

I went through the gcode and found two places where Cura sets nozzle temp way higher than set in the Material settings in Cura.  I do not see any other place in the setting that would change the temp.  Editing the gcode to make all the M104 commands read the desired temp resulted in a VERY GOOD print.

 

Attached gcode file generated with Cura 4.7.1 using Recommended settings.  Note the temp changes (M104) about 1/3 and 2/3 the way through.  Starts at 205 (desired) and then goes to 245 followed by 240.

 

Why/where does Cura change the nozzle temp midway through the print?  Is there a way to change this?  retractions_2.gcodeEasy to see why I am getting stringing when nozzle temp jumps to 245 with PLA.  

 

Tried the same retraction tower model with PursaSlicer and it also turned out pretty good.

[GregValiant 1,248]

You have a Plug-in active.  From the code (shown below) it's ChangeatZ and there are 4 of them.

 

Line #11         ;POSTPROCESSED ;Big clue there

Line#10626    ;[CAZD:
Line#10627    M104 S250.0 T0
Line#10628    ;:CAZD]

 

Next to the Slice button is an icon with a crossed hammer and wrench that probably has a red circle next to it.  Click on the icon and then click on the |X| next to each ChangeAtZ plugin.  That will get rid of them.  Then you can re-slice.

Edited September 28, 2020 by GregValiant

[lenp49 0]

Greg,  Many thanks for that!!  Now I have to ask "how in the world did that get in there?"  I was using "recommended" settings and it looks like this happened with "experimental" settings.  I sure don't recall setting anything under experimental other than using Tree support a couple of times.

 

Great to know and keep an eye out for that red circle.

 

Thanks again,

Len

[GregValiant 1,248]

My pleasure.

It is exceedingly unlikely that the ChangeAtZ plugin just one day decided "Hey, I think I know how to drive this guy nuts" and then jumped into your gcode FOUR TIMES, and then filled in it's own settings FOUR TIMES.  Did you happen to open a 3mf file that somebody else created?  That might do it since a 3mf Cura Project file has just about everything in it.

[lenp49 0]

Greg, I have no recollection of opening anybody else's files but may well have.  Typically I just import (open) an STL file and slice that.  I was messing around with tree supports but don't think that would cause this.  Oh well, I will just watch for the red circle from now on.

 

All this after spending $200 and three days adding direct drive extruders to get rid of stringing. when all along it was a temperature issue.  Lesson learned.

 

Thanks again for the help!

Len