Multiple extruder with skeinforge

"I think the support for multiple extruders has to begin with Skeinforge." I read on IRC (always a good place to check sometimes)

That's true, since we have several x-carriage designs that can support two extruders, or even RAMPS 1.3 with room for a 5th stepper driver, only the software part seems to be missing.

But reading that I was thinking :
In the alteration folder, we already modified the start.gcode and end.gcode.
And there is also a support.gcode to micro-manage the support as enrique said.

So, can't we do that with the alteration file ? By just adding :

support_start.gcode :

G1 E-2 FXXXX (retract extruder A to stop extrusion)
T1 (select new extruder)
G1 X-20 FXXXX (move the x-carriage to compensate the distance between the two nozzle)
G92 E0 (set extruder home or something like that)

support_end.gcode:

G1 E-2 FXXXX (retract extruder B to stop extrusion)
T0 (select previous extruder)
G1 X-20 FXXXX (move the x-carriage)
G92 E0 (set extruder home or something like that)

Just a thought
(finally don't we have all we need ?)

ps : in thing:6632 ScribbleJ already did a dual material print, but in this case we don't have to made different stl, skeinforge will do all the work

The firmware is the limiting factor, not skeinforge. (I'm assuming the support start/stop alteration files do indeed work)

From what I have worked out, the skeinforge support start needs to contain something like this:

support.START.gcode

G1 F2400
G1 E-5 (severe retract on the primary material nozzle)
T1 (switch extruder control)
G1 F6000
G1 X0 Y0 (go to 0,0)
G1 X-22.45 Y.08 (offset head by appropriate value so the support nozzle is exactly where primary nozzle was)
G92 X0 Y0 (call the current location of the support nozzle 0,0)
G1 F2400
G1 E5 (advance forward to make up for a previous retract)


support.END.gcode

G1 F2400
G1 E-5 (severe retract on the support material nozzle)
T0 (switch extruder control)
G1 F6000
G1 X0 Y0 (go to 0,0)
G1 X 22.45 Y-.08 (offset head by appropriate value so primary nozzle is exactly where support nozzle was)
G92 X0 Y0 (call the current location of the primary nozzle 0,0)
G1 F2400
G1 E5 (advance forward to make up for a previous retract)

All that is absolutely necessary for support material is firmware which reads t0, t1 commands, and sends signals to the appropriate step and direction pins. Everything else can be done easily enough in the current skeinforge. (For Teacup anyway, since it is already easy to specify additional temperature controlled heaters)

The hard part will be nozzle alignment, controlling ooze, and eventually creating a more advanced support structure.

Edited 1 time(s). Last edit at 08/10/2011 08:02PM by Andrew Diehl.

I'd think a new M code that sets a position offset would be the way to do this..

support.START.gcode
M1234 X-50 Y-50

support.START.gcode
M1234 X0 Y0

The start sets the offset of the 'support nozzle', the end retuns the offset back to the default/primary/t#0 nozzle.