gcode to load filament

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Penged
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gcode to load filament

Postby Penged » Sun Nov 06, 2016 7:21 am

Howdy all,

I guess this is a 2 part question. The easy one is what G code would you use to have the filament feed itself down the bowden tube once the extruder motor engages with it. The second question is how do you learn how to write the macro for this sort of thing? Web sites, books, or other resources would be appreciated. The software side of life puzzles me to no end.
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IMBoring25
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Re: gcode to load filament

Postby IMBoring25 » Sun Nov 06, 2016 9:11 am

It's pretty straightforward if you have the g-code reference, which is at http://reprap.org/wiki/G-code

The SeeMe machines use Repetier firmware, so that's the section of that reference you want to use.

For this, your primary command will be G1 with an E parameter of the length of your Bowden tube in mm and an optional F parameter of the desired extrusion speed in mm/min.

There are a few potential complications:

If the hot end is not up to temperature you may need to allow cold extrusion for the move (which is normally disallowed so you don't hit a cold hot-end and grind the filament in the extruder drive to dust). If you're running the latest firmware, that should be M302 S0 to allow cold extrusion and M302 S170 to disallow it again after the move.

If you are in absolute extrusion coordinates mode, you need to reset the extrusion axis before and after the move using G92 E0 or you may have unpredictable results.

Repetier has a maximum extrusion length parameter buried in the firmware to protect against wildly long extruder moves resulting from errors in absolute/relative mode selection. You may need to break the long move into several shorter ones to keep the firmware from ignoring the move.

You can get close automatically if you know the length of your Bowden tube. To be perfect, you really need to extrude a little extra and pull off the ooze. Without a purge canister like the commercial machines use that calls for some manual user intervention.

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mhackney
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Re: gcode to load filament

Postby mhackney » Sun Nov 06, 2016 9:30 am

My code for feeding filament:

10 M3000 Depress Extruder Lever
20 M3013 Push Filament By Hand Until It Reaches the Hot End
30 M3021 Push A Little Further To Purge Old Color
40 M3014 Stop Pushing To Equalize Pressure To Prevent Drool
50 M3001 Release Extruder Lever

Or something similar to that.

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Penged
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Re: gcode to load filament

Postby Penged » Sun Nov 06, 2016 11:30 am

So if my bowden tube was 600 mm long i'm guessing I would create a macro that is something like;

M302 S0 (cold extrusion min temp 0)
G1 E600 (linear move extrude 600 mm)
M302 S170 (cold extrusion min temp 170)

Ok so if I add M81 (turn off ATX power supply) to the end G code commands it should turn off the power supply when the print is finished correct? Or would M85( inactivity shut down timer) be a better option? This is in reference to a different question I asked in the build zone about turning off the light ring being powered by the HE280 board.
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IMBoring25
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Re: gcode to load filament

Postby IMBoring25 » Sun Nov 06, 2016 12:10 pm

I think I read viewtopic.php?t=2713 as saying you have to wire your Rambo and PSU differently to get M81 to function. M85 is a different function. It sets the motors to power down after a specified period of inactivity. It doesn't touch the power supply.

Penged
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Re: gcode to load filament

Postby Penged » Mon Nov 07, 2016 5:22 am

Mchackney, I'm guessing that you are insinuating I am making a mountain out of a molehill and your probably correct. :P
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mhackney
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Re: gcode to load filament

Postby mhackney » Mon Nov 07, 2016 12:10 pm

yes :)

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