[solved for me]SF 41 reverses extruder before build

Hi,

we've just finished our Sells Mendel build - mechanically at least. Because we haven't gotten the Reprap host software to communicate with the printer on any PC, we're using SF 41 and pronterface to control the printer.
There is just one little problem left with skeinforge, that is right before the extruder lays down the first bit of filament, it starts going backwards at ~300mm/min and reverses a good bit of filament out of the extruder, enough to get it into the hobbed bolt (if you're slow on the emergecy stop). I've tried picking around in the gcode but didn't get anywhere.
SF and the extruder are set up as far as extrusion speed and direction goes, as we've been able to extrude plastic and "print" the first layer of the raft.

Hardware:
Sanguinololulolu 1.2 + Sprinter (recent)

Software:
SF 41 + pronterface (recent)
Ubuntu 11.04 (if that matters)

I hope someone can help us. We're a two man team and have both spent about 50 hours working on the Reprap. I just want to get printing!

I'll post the gcode tomorrow.


Thanks!

-imitation-

Edited 1 time(s). Last edit at 09/07/2011 02:10PM by imitation.

You need to edit the start.gcode file in the alterations folder in skeinforge to include a G92 E0 to reset the extruder position to zero. If not, it starts at a position based on how much you've manually extruded by pressing the extrude button before printing your part.

Hi, You could also use SFACTa derivative of Skeinforge that has automated settings.
It has an option (enabled by default) to send an G92 E0 command before starting the print. (Under "Preface" Plugin)

---

Manufacturer of low tolerance Filaments PLA, ABS, ASA, PETG, TPU, PA, PVA,
[www.miafilament.com]
[github.com]

I checked in the gcode, there is a G92 E0 in there - however Sprinter doesn't seem to take notice. What's working for me is this:
> Heat up
> Get extruder going
> Reset
> Home
> Print

I'll try a more recent version of Sprinter or Marlin someday.
Now i just need to find a way to print ABS without a heated bed...


Thanks!

Here's another solution to it - way cooler and more comfortable. I created a start.gcode that would do a couple G92 E0 before the build and a some other things, like a M109 S240 that Skeinforge doesn't think is neccesary.

Cheers!