Extruder retracting filament at start of print

OK, I've looked everywhere, what setting would make skeinforge retract an inch or more of filament at the start of a print? I can't see or understand what in the g-code would cause this. Anyone have an idea as to what setting might cause this?

It's always a good idea to have a "G92 E0" statement at the front of your gcode. You can get this in skeinforge through the start alteration file. This command resets the E axis. Basically what it tells the firmware is "Whatever your current position is - consider that to be 0". That way your first extrude command will be relative to 0 which is probably what you want.

Without this command, the E axis will retain the value from whatever it was doing before - including manual extrusions.

I got burned by this very early on when I switched from Slic3r to skeinforge, except my retraction wasn't just an inch. It retracted at a relatively high speed for a good 15 seconds. It took quite a bit of effort to get the hobbed bolt cleaned out.

Thanks. I'll add that.

Into my start.gcode, just after having purged the nozzle, I write this:

Quote

G92 E0 (as said by Jbernardis)
G1 X100 Y100 E-3.0 F4500 (going to the center of Mendel's plate and retracting filament for 3 mm)

After that, gcode written by Skeinforge automatically pushes the 3 mm just before printing.

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François