E values in Gcode?

[Eureka]

Does anyone know exactly what the E values in the Gcode stands for? I understand it has to do with the feeding of filament, but what is the unit for these numbers? Are they millimeters?

Just curius.

[ddurant]

I think you only see E in 5D gcode..

 

For old skool 5D, the number is the length (mm) of plastic noodle that should come out of the nozzle.

 

For volumetric 5D, the number is the length of raw filament stock that should go into the extruder drive.

 

Gcode generated for one is VERY incompatible with the other.

[Eureka]

5D? The only thing i know is that im using replicatorG for the replicator 1 machine, using the skeinforge 50 slicer....does that give any clue?

[Dan Newman]

They are in the units specified by the gcode and it's generally safe to
assume
millimeters (a gcode of G21 sets that).

Dan

[ddurant]

5D was an enhancement to gcode that was made a couple years or so ago. Most machines have been happily using it for a long time and have even moved to the successor to 5D, volumetric 5D, about 18 months ago.

 

Gcode files are just text files. Many, many lines of text that tell the printer what to do. A good gcode reference can be found at http://reprap.org/wiki/G-code .

 

> 5D?

 

The short, short story is that 5D changed gcode so that all 5 dimensions (x, y, z, extrusion and time) that go into each thread of a print could be specified in a single line of gcode.  

 

Anyway, it's not something you really need to understand if you don't want to. The E value in gcode just tells the firmware how much filament should be processed. It means different things on versions of 5D but you probably can ignore that detail, if you want.