[WIP] another direct dual extruder

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Trnquill
Posts: 66
Joined: Fri Oct 05, 2012 10:01 am

Re: [WIP] another direct dual extruder

Post by Trnquill »

satoer wrote:I think the best way to avoid oozing is a single head extruder with two feeds.
How do you purge (clean) the head when changing colors or materials? Some material needs to be extruded in order to make sure you get only the new stuff, not remains of the old.

When I change filaments I pull out the old and insert new. After that I have to extrude few centimeters to get clean color. Before that I get the old color for a moment, then mix of the two and only after that fresh new filament.

Kjetilei
Posts: 334
Joined: Fri Mar 16, 2012 8:26 pm
Location: Stavanger, Norway

Post by Kjetilei »

When I change from my blue filament to my yellow filament I have to extrude for quite a long period to totally flush the blue remnants.

I have also read a little bit about the work being done on a single hot end with multiple filament feeds but I believe you would need a proper purge area (being able to move outside hot bed or have a hole in the hot bed) or hide the filament change in the inn fill of an object (problematic with transparent material)

Guillaume has used some of the rubber like soft PLA but I have not heard/read much about his experiences except that it works nicely with his updated extruder.

When I checked a while ago I only found 3mm filament from a German supplier but the availability situation has obviously changed to the better since then.

satoer
Posts: 436
Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

If you can find a way to construct a hot end where the two colors combine just before the output hole, I don’t think you have to purge the head when extruding a new color.
Image

I don’t have much machining knowledge, so I don’t know if it’s possible to machine it like this. But if you create the inlet feeds diagonally it shouldn’t be a problem to machine it.
Otherwise, If you have bit programming skills, I don’t think it’s very hard to adjust the firmware yourself to create a dump fillament routine between the color change.
I don’t know a solution for the difference in heat though… But in my experience I haven’t found much difference between temprature’s.
My Felix 1.5 printed designs on Thingiverse
E3D V6 Hot end upgrade for your Felix
Tweezer bracket for your Felix
Led bar upgrade for your Felix

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

Seems like I have a stable setup now, with another iteration of the printed parts extruder parts :)

Here are some results:
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Works nicely now, if a manual "skirt" is setup around each object that wipes ooze off the extruder heads. Adding a fan to blow on the extrusion made a huge difference as far as curled corners and perimeters are concerned.

Also, the material combination matters. Opaque black/white makes imperfections quite visible, and I have not succeeded in getting acceptable prints. However, this red / glow in the dark combo worked out quite well, as little smidges of the wrong material are much less visible.

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

So, here come the STL files for the design, plus some images, in case anybody else wants to try it out. I've been using it for the last few weeks without much trouble. However, I recommend upping the fan voltage to 12V for the "cold-end" fan, to prevent plugs forming during dual extrusion, in the idle extruder. The design is for Felix v1.5, with the Hiwin rails.
dual-extruder.zip
dual extruder STL files
(616.16 KiB) Downloaded 128 times
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And the "faceplate", as it's the most complicated part.

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Also, I have both fans on the extruder always running off 12V, with no ill-effects so far. The lower fan duct isn't optimal, though.

Kjetilei
Posts: 334
Joined: Fri Mar 16, 2012 8:26 pm
Location: Stavanger, Norway

Post by Kjetilei »

Thanks for the update and sharing the files.

I too upped my fan to 12v to be on the safe side regarding sufficient cooling.

Why do you feel that the lower fan duct is not optimal? Too little air blowing around the hot ends or something else?

I have done some improvements to my design but not yet had the capacity to print all the parts (the printer is in "storage mode" downstairs at the moment but will hopefully be put in action next week).

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

I get noticable curling on the far side of the fan, while the near side is much better. I guess I need either a 2nd fan down there, or some fancier ducting.

stratogavster
Posts: 120
Joined: Tue Jul 17, 2012 9:04 pm
Location: United Kingdom

Post by stratogavster »

Hello All,

Wondered if there has been any progress with the dual-extrusion?....any examples to show us all?

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

I've been busy with other things, among them fiddling with the Z axis. But, also other things not related to 3D printing. In the meantime, I've only done a few long single-material prints, and the extruders seem to work as well as Guillaume's design. I'll hopefully have some more parts to print in March, maybe I can even get some PVA filament for printing supports.

dognotdog
Posts: 181
Joined: Tue Sep 04, 2012 9:22 pm

Post by dognotdog »

lawong, i can download and unzip it just fine, so please try again. This is should be able to print both. I've made it out of PLA, and have only printed PLA with it so far. I haven't tested if the higher temps with ABS would cause any trouble.

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