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Manualy joined parts of gcode behave strange


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Posted · Manualy joined parts of gcode behave strange

I designed one lamp shade, and trying to print it in spiralize (vase) mode. However, base of this model can not be printed in spiralized mode because it need some infil and thickness. So I have made slicing two times. One time for whole model in normal mode, then another time again for whole model, but in spiral mode. Then I opened first gcode file, found where layer 20 starts, and removed everything after that. Then from another gcode file I have taken everything starting with layer 20, and copy to first file.


I was expecting that printer would just continue printing, but somwhere at this joint, printer makes one move with extra slow speed (like 1 mm/s), and in same time removes filament from printer, like when you give it comand to change fillament.


I suspect that problem is E command which is quite diffrent for same layer in those two files. Jums from 1297 down to 640?

But why speed is slowing down. Because x-y move is streched over time it needs for E move from 1297 to 640?


What's better way to do this?


"Modify settings for overlaps" can not work for this, because there is no "spiralize" mode to choose here for modification.



G1 X24.346 Y-2.187 E1297.95365
G1 X24.43 Y-.821 E1297.97813
G1 X24.451 Y-.314 E1297.98752
G1 X24.46 Y-.1 E1297.99161
G0 F7200 X24.66 Y-.1
G0 F600 X24.66 Y-.1 Z4.3
G0 F7200 X24.66 Y0.00
G0 X24.239 Y2.186
G0 X24.189 Y2.189
;MESH:LAMP_SHADE v2.2 wall_0.6_mm.stl
G1 X30.642 Y0.099 E640.51694
G1 X24.511 Y0.1 Z4.303 E640.72085
G1 X24.423 Y0.917 E640.74819
G1 X24.331 Y2.476 Z4.304 E640.80013
G1 X24.254 Y3.179 Z4.305 E640.82365
G1 X24.009 Y4.725 E640.87571
G1 X23.879 Y5.438 Z4.306 E640.89982
G1 X23.791 Y5.797 E640.91211
G1 X23.399 Y7.319 Z4.307 E640.96439


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    Posted · Manualy joined parts of gcode behave strange

    So close!!  You almost got it.  You actually only have one issue.  When it moves the filament from position E1297 to E640 it is moving back about 0.6 meters.  That axis (E axis) has it's own speed limit and the move is supposed to be linearly such that it reaches it's X and Y position at the same time as it's new E position - hence it is moving the print head MUCH slower than usual.


    Anyway the fix is to tell the printer that we are now already at 640.51694 so it doesn't move backwards.


    So you need a G92 E command:


    G92 E640.1


    Right after printing at E1297 insert the above command.  This will tell the printer that the E axis is now at 640.1mm so that when it gets the command E640.51694 it will only move forward slightly.  To do it perfectly right - look at the line of code in the original file that you "threw away" and find the last E position before it does the E640.51694.  Steal that value and put it after the G92 as shown above.


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    Posted (edited) · Manualy joined parts of gcode behave strange

    A little food for thought...

    The first line of the vase mode file is an extrusion.  It went from a previous point that is no longer in the gcode, to X30.642 Y0.099 E640.51694.  In your patched code you are defining the start of that first extrusion as X24.189 Y2.189.  Is it close to where it was in the first file?  Is it on the correct extrusion path for the vase mode file?  You know it wasn't calculated to be on that path.

    In this case since it is such a short distance it probably doesn't matter.  There are certainly cases where it does matter.  If retractions are involved then there would need to be a prime as well.


    I would do it this way:


    G0 X24.189 Y2.189




    ;MESH:LAMP_SHADE v2.2 wall_0.6_mm.stl

    G92 E640.51694

    G1 X30.642 Y0.099 E640.51694  ;Turn this into just a move that you know is on the vase mode extrusion path

    G1 X24.511 Y0.1 Z4.303 E640.72085  ;The G92 line sets the extruder so it is correct at the start point of this line.

    G1 X24.423 Y0.917 E640.74819


    It's real close to gr5's suggestion.  The difference is that without having the exact start of the first extrusion, we ignore it, get to where we need to be, and move on.

    Edited by GregValiant
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