Timeline for How do the E commands in G-code work, exactly?
Current License: CC BY-SA 3.0
8 events
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| Jul 1 at 10:36 | comment | added | SF. | @yeemonic Invention of retraction was a big revolution in 3d printing. In short, a 3D printer when stopping extrusion, performs a short move of the extruder in negative direction, pulling some of the filament in, resulting in much neater ending, much reduced stringing. Before resuming printing, it extrudes as much as it retracted to return the filament to the nozzle tip. The retracted position is the standard 'rest position' for a nozzle, so you'll always see a bit of extrusion at start in the g-code (and retraction at the end). | |
| Nov 10, 2016 at 18:25 | comment | added | yeemonic |
As a related question that I don't think warrants its own post, what is the significance of these 3 lines? G92 E0 -- G1 X124.746 Y125.952 F7800.000 -- G1 E1.00000 F2400.00000 From what I understand, the first "resets" the counter for E. But what about the 3rd? Does this just extrude in place without moving? Seems a bit odd...Especially since an extrusion increment of 1.0000 is much greater than we'd tend to see in any other single line (skimming through the file I'm looking at, the highest seems to be ~0.3).
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| Nov 10, 2016 at 17:58 | vote | accept | yeemonic | ||
| Nov 9, 2016 at 14:31 | comment | added | Tom van der Zanden | If you want to move from one side of the print to the other, unless the current layer is convex, the straight line from one part to another might cross the boundary of the current layer being built. This results in stringing and blobs (extra material on the outside of a print) since a little material oozes out of the nozzle (even when you're not extruding). By following the contour of the part (and not moving in a straight line) you can prevent (or minimize) the distance traveled on the outside | |
| Nov 9, 2016 at 14:18 | comment | added | yeemonic | Sorry - what is stringing? Is that like "oozing" or "leaking" kind of? I looked it up - gotcha. That makes more sense now. Thanks. | |
| Nov 9, 2016 at 14:18 | comment | added | Tom van der Zanden | Sometimes you don't want a travel move to happen in a straight line. Generally, to avoid stringing, you want the majority of a move to happen "inside" a part, so that the smallest amount of the move is through free air. This means the shortest/best path from one point to another is not necessarily a straight line. | |
| Nov 9, 2016 at 14:16 | comment | added | yeemonic | In that case, what is the point of a segment of code such as this? : G92 E0 G1 X55.571 Y120.585 F7800.000 G1 X55.571 Y103.100 F7800.000 G1 X55.571 Y96.900 F7800.000 G1 X55.571 Y79.415 F7800.000 G1 X63.907 Y77.129 F7800.000 G1 E1.00000 F2400.00000 Why would it make 5 movements without any extrusion? | |
| Nov 8, 2016 at 22:25 | history | answered | Tom van der Zanden | CC BY-SA 3.0 |