Whatif Extruder axis is not E?

Development
1

So in CNC you can have any number of axis setup by various names. X,Y,Z,A,B,C. 3D printers use E. Is there anyway I can tell Octoprint (or the slicer if need be) that the Extruder's axis is called A?

2

Is this a problem or just speculation/curiosity?

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3

For it is an agreement that E is the extruder for 3D printing (in combination with T for tool select) and also that OctoPrint is made to work with 3D printers in very first place, I don't think that is is that easy so make changes to OctoPrint and/or the slicers to use another letter for the extruder or tool.
https://reprap.org/wiki/G-code#Fields

4

You might want to read through all this. Active work is being done to extend OctoPrint beyond just 3D printing.

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I ended up writing a filter that changes E into A for my purposes. In my slicer (Simplify) there is no way to change the extruder from E to anything else. Come to think of it, I haven't seen a slicer that can at all.

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Yes, it's a problem not just speculation.

7

So.. what's the problem? Or do we need to guess?

8

Lol, sorry.

My g-code intepreter has six axies x,y,z,a,b,c it does not support E. All of the commands that go to E should really go to Tool 1 or to A. that's the problem.

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AFAIK, one of the gcode flavors in Cura supports A B C as extruders.

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It does?! Sweet! I'll have to investigate further. Therefore if Cura outputs A as the extruder, the octoprint will honor it right?

11

octoprint don't care what's after G1/G0, it will pass the gcode to the printer so it's slicer/printer issue, not octoprint....

as for s3d, there is a postprocessor where you can replace all E in to A, look at scripts tab, "additional terminal commands..." field .. there you can {REPLACE ...} should be possible to replace all E to A ....

iirc cura's "mach3" flavor shoots A instead of E but that was broken for a while, should be fixed in latest version of cura .. look at the gcode if there is "Flavor: marlin" if you select mach3 in cura then it's version with a bug. (this is the bug report: https://github.com/Ultimaker/Cura/issues/4929 here's the permalink in cura how it handles extruders in mach3 flavor https://github.com/Ultimaker/CuraEngine/blob/b11420f9c59e6e6951e3577523ba764fbc7035d8/src/gcodeExport.cpp#L322 )

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