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Topic: dual extruders

Just curious if someone has considered an upgrade to dual extruder and/or an opinion on how much it would take to get dual extruders operating functionally on a solidoodle. I'm highly anticipating my printer and the possibilities but with the open source ability of the machine, would this be truly capable and a worth while modification.

I saw a dual extruder in a past kickstarter campaign that would probably work nicely for the task

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Re: dual extruders

The Sanguinololu electronics that run the Solidoodle only have 4 stepper motor drivers (X,Y,Z,E1). You would need to change the electronics to a board like RAMPS before you even worried about the physical addition of the second extruder.

http://reprap.org/wiki/Ramps

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Re: dual extruders

Answers my question. Thanks for the quick reply. Was more or less wondering about plausibility over everything.

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Re: dual extruders

Sorry to revive this 4 months old post,
I was wondering, does the extruder really need "backward" functionality?

Solidoodle2 with Ceramic tile heated bed http://www.soliforum.com/topic/2544/my- … eated-bed/
"1kg should last for an while" is a lie!

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Re: dual extruders

I'm not sure what you mean by backward functionality in this case.   I will be working on dual Bowden style extruders when my order comes in this week. First things first, as Lawsy said, you have to upgrade your board. It seems like the Azteeg x3 is the most common choice here. For the Solidoodle, you would be really pushing the bounds by trying to use 2 motors on the carriage because of the weight and space requirements. You also may want to upgrade the power supply to handle the extra current draw since one extruder will be sitting still most of the time. Also there would need to be a clever way of making sure the two extruders are level. The next MKxx replacement that we make here should be for a dual Bowden style extruder... It would be an exciting path to try with the SD2.

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Re: dual extruders

Seems plausible to me that instead of an additional stepper drive you could have them both running from a switch?

7 (edited by jooshs 2013-01-12 19:45:34)

Re: dual extruders

I couldn't think of a good way to use a switch and spent several months thinking about it. The closest to achieving this would be this I think.  Still think this uses several motors also though.

http://www.thingiverse.com/thing:23775

That is too big to be up on the carriage so it is possible it could be used in a Bowden style extruder, but wouldn't allow for quick changes in colors and not sure about the reliability of this for Bowden style extrusion. It would never work back an forth with PLA or PVA and abs for soluble support either. I would love to hear any other ideas for switching though. I am all about us coming up with a good solution.

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Re: dual extruders

asmacdo wrote:

Seems plausible to me that instead of an additional stepper drive you could have them both running from a switch?

Yes that is exactly what i was thinking.
driver's input is one for step and one for direction. that's why i asked the question. is "backward" direction really used in the gcodes?

can anyone throw out ideas about switch concepts and turn the existing 4th driver (E driver) into dual extruder?

Solidoodle2 with Ceramic tile heated bed http://www.soliforum.com/topic/2544/my- … eated-bed/
"1kg should last for an while" is a lie!

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Re: dual extruders

RavensCrest wrote:

is "backward" direction really used in the gcodes?

can anyone throw out ideas about switch concepts and turn the existing 4th driver (E driver) into dual extruder?

Backwards direction is definitely used - that's retraction, how else would you change filament! (Plus, it's used during extrusion to relieve pressure when moving to another area)

The A4988 chips have enable pins, but they're all tied together on the Sanguinololu. You'd have to cut the trace to the E driver, stack another A4988 breakout on top of the existing E driver, wire the enable pin to separate DOs on the ATMega644 chip, and then modify the firmware.

http://reprap.org/mediawiki/images/f/f5 … u_1.3a.png

So, like most things, the answer is "yes, but..."

10 (edited by asmacdo 2013-01-14 03:14:35)

Re: dual extruders

What about something like this:

(Please excuse the terrible drawing)

Everything encased by the acrylic is duplicated. The gear that grabs the filament is connected to its counterpart in the extra encasement and the motor always runs both gears together. The switch happens on the other side of the filament, the metal roller and spring. If tense, that side extrudes.

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Re: dual extruders

asmacdo wrote:

What about something like this:

(Please excuse the terrible drawing)

Everything encased by the acrylic is duplicated. The gear that grabs the filament is connected to its counterpart in the extra encasement and the motor always runs both gears together. The switch happens on the other side of the filament, the metal roller and spring. If tense, that side extrudes.

One of the problems is that you can't add much mass to the extruder assembly without having to drop print speed/acceleration limits.

The other problem is developing a reliable mechanism to do what you described.

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Re: dual extruders

Got a couple of vague mechanical ideas cooking that will hopefully solve both of those problems. I will post if I figure it out. I will need help on the electronics side though.

Another problem that I don't know how to approach is how to prevent ooze from the unused hot end.

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Re: dual extruders

Preventing ooze is retraction setting.

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Re: dual extruders

elmoret wrote:

Backwards direction is definitely used - that's retraction, how else would you change filament! (Plus, it's used during extrusion to relieve pressure when moving to another area)

Thank you for your knowledge.  I guess spliting e-motor won't work.

while searching for other pins to add fifth motor driver.. i ran across this.

reprap.org/wiki/SLUM

i hope his prototype works. since buying a new Azteeg x3 will be +200 and adding extruder and nm17 that would be over budget for me... unless I am to build a new printer all togather.. :-(

Solidoodle2 with Ceramic tile heated bed http://www.soliforum.com/topic/2544/my- … eated-bed/
"1kg should last for an while" is a lie!

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Re: dual extruders

I think ooze shouldn't be too much of an issue with an idle extruder since it should be off when not extruding. I think ooze is more of a problem with the active extruder. Also, a way to make sure both extruders are level with each other and the bed can be tricky. Does the sang have a way to wire in an extra heater and thermistor for the 2nd hot end?  I know you would need another MOSFET or somehow to wire the extruder heaters out in parallel?  I might be lost on this thread, but is it still aiming at making the dual mod without upgrading the board?  If so, maybe I'll start a second thread for those willing to upgrade the board.

Another thing that isn't a deal breaker, but may be sort of complex to solve in firmware or gcode is how to know when you are extruding from one hot end or the other. I imagine it would have to be something like telling your gcode that both extruders come from the same source, e in the sang case. These are some of the reasons I would think two motors would work better.

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Re: dual extruders

Here is a starting place for looking at this- http://www.thingiverse.com/thing:16523

He is using two Makergear hotends with Bowden tubes, which is pretty much what the Solidoodle would do.  It also requires a RAMPS.  I think trying to force the Sanguinololu to support two extruders is a losing proposition.  There will be enough complications without adding that in as well, so it's best to start with electronics that already support the mod.  It might be tricky to do dual extruders on RAMPS and still keep a gcode controlled nozzle fan, so the Azteeg X3 would be best I think.

The Azteeg is just over $100 if you don't buy stepper drivers for $50 more.  You could keep the Pololu drivers from the Sanguinololu and buy one more for the extra extruder.

KISSlicer is probably the best one to use for dual extrusion.  It was developed by a BfB user, and those printers have had dual extruders for a long time.  It has separate retraction settings for the unused extruder, so you can pull the filament further back to prevent ooze, and there are also cool down and warmup controls.  There is also a wipe pillar- I haven't looked at it much but I believe it is a cylinder that gets built along with the part.  When the second extruder is ready to print, it runs over the pillar so that any ooze gets wiped off there rather than on the part.

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Re: dual extruders

I think that the trick to getting this to work well is that it must be as minimal as possible.

I am not opposed to upgrading the board, I am more concerned about the weight of the assembly. Other than going bowden it seems best to have only 1 motor.

I haven't really considered the code side yet, but that does seem tricky at least.

18 (edited by Rondavouz 2013-01-15 17:03:03)

Re: dual extruders

Teaser Time!

http://forumbilder.se/images/235201355632Pc0d0.jpg

http://forumbilder.se/images/bf5201355758Pf53d.jpg

Working on leveling the second extruder atm. Will be back soon!

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Re: dual extruders

Rondavouz,

Great stuff! Feel free to drop by the Bowden thread and add any lessons/tips/material choices that you have.

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Re: dual extruders

Oh my. That's nice.

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Re: dual extruders

cool smile

SD2 - Glass Bed, Fans on PCB and Y motor, Custom enclosure
Slicer - Simplify3D

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Re: dual extruders

Now I'm excited.  Great stuff, can't wait to see more.

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Re: dual extruders

It was only a matter of time.  Very interesting,  congrats on the work,  looks pretty decent as well

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Re: dual extruders

Is it strange that I'm starting to drool from seeing this dual extruder setup on the doodle? Very nice indeed. Can't wait to see more on it.

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Re: dual extruders

Jealous!

Solidoodle2 with Ceramic tile heated bed http://www.soliforum.com/topic/2544/my- … eated-bed/
"1kg should last for an while" is a lie!