MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.

Download Now


3Dator Y-piece for dual extrusion with one nozzle

by 3Dator Jul 19, 2016
Download All Files

Thing Apps Enabled

Please Login to Comment

Hi folks,
Just finished one copy of your „tool“.
I printed the Y-Splitter with PLA, we will see what the time says....
I made abt 30 color swaps and had no issue.
I took your presets for S3D and checked the chnages with the provided macros (code snippets)

Tomorrow I will make some fine tuning and start my first dual color print with this technique...
On my other printer I use E3D Chimera/Cyclops, which works fine. But much more expensive :-)
Thanks for the open source files.

Any progress on this? are you still using it? if yes how does you s3d toolchanging script look like now, if you want to share :)

Did you ever get this to work with S3D? If so can you please share your settings for tool change start etc.

Hi jskala,
it is working fine on my Delta, someone else made it on the i3 MEGA . I am waiting for my stepper motors and extruder, then I will use it for the MEGA as well.
I used the code which is provided on their WIKI.
At the moment, I am on a business travel and don't have my S3D around:-)
I will reply on Saturday.....

Hi fvt,

can you share your tool change script. How does it works wit an prime tower?

I should use 1/8" or M6 fittings?

The M5 ones. See the description for more details. You can also buy them in our online shop: https://3dator.com/shop/ptfe-fitting-pc4-m5/

I have to say that I ran into quite some issues with this design. Josef Prusa summarized my own experiences pretty much perfectly:

Read all the delays Josef ran into... Delay#1 and #3 are pretty much the same I had problems with. Everything works super-ok like 10 filament switches and then it jams out of nowhere (on PLA -- like a lot of others here mentioned. I did not try PETG).

Please don't get me wrong: I do not want to ramble around, but I would suggest to anyone, who wants to give this a try, to lower expectations. There are reaaaally good reasons why dual extrusion setups similar to this retail for > 200 USD (Prometheus) or are still in development (Prusa I3 MK2). Up until then use this with PETG / PVA only, as 3Dator suggests.

You are right, this is not easy until you get it running. Try to play a bit with the print temperature. We also printed PLA with that system.

is there maybe a brand of PLA that isnt stringing so much?


I just printed and set up the y piece on my printer and I remembered reading something about the strings of pla that happen when the material is pulled out, is that still a concern?

yes, it is the biggest concern. Read through the comments where are a few approached to get rid of them.

Wow, looks very cool! Is this still being supported?

Im ordering my second extruder and extruder motor. Ill print this out tonight.

Does this work with marlin? Repetier host? Is the wipe tower part of the slicer or part of the code?

We're still supporting it!

Repetier should work fine, not 100% sure with the newest Marlin firmware. We added the feature to our own Marlin based firmware.

The wipe Tower is generated by the slicer.

@3Dator - Looks like the inner diameter of the holes in the Y are 2.5mm. Why did you choose 2.5mm? I think 2.0mm might work better since the tubing and the coupler diameters are (or should be) 2.0mm. 2.5mm might make pushing the filament into the bottom coupler more difficult, since filament (particularly once its been heated and cooled) could catch on the 0.25mm "ring" between the ID of the Y path and the ID of the coupler. If the entire path (tubing, couplers, and Y) was 2.0mm it seems like there'd be a much larger chance that the filament wouldn't get hung up on any of the 4 or more joints the filament has to travel through.

Would you mind uploading a version with a 2mm hole? I'd be happy to compare the performance of the two versions...

You are probably right. We made the tube a bit bigger that the filament can't get stuck even with not perfect print quality.
Tipp: we used a metal drill to make a funnel shape on the end of the single fitting. So the filament will find its way into the fitting.
We won't add a second file. You can edit the step file pretty easily.

What did you use to generate the step file? When I google "3d printing editing step files" all I seem to get are stl editors...

we use fusion 360 for that

Hello, Could you please provide the fusion 360 file for this model ? I would like to try out this diameter modification that Yonkiman suggested

Comments deleted.

Did you try ABS + HIPS?
The main problem of one nozzle approach is that a ABS become brittle. Hotend is not clear enough after color changing.You need prime tower very big.

We tryed PETG + PVA that worked really good. You may be right with ABS. This setup does not solve all problems but is pretty easy to use.

Were you using the same tool change G-code on your page for this setup? What kind of temps were you using for the PVA and PETG? I have gotten a setup working reliably with PLA but when I try running PVA + PLA I run into lots of issues.

yes we used the G-Code that is provided through our wiki. We used 210 °C for both PLA and PVA with a e3d vulcano. We haven't had any extrusion problems but the PLA layers didn't stick well enough to each other because of the low temperature.
If you like we can help you in detail. Just send a PM :)

didn't fit my tube sadly

It works!!!! I made one, and I got the retraction working reliably (if not quickly) with my E3D Lite6! Here's what I know:


1) The closer the inner diameters of the tubes, couplers, and Y-device match, the better. The inner diameter of the threaded part of the couplers never seems to be spec'ed, so you may want to buy 3 each of several different brands. My blue couplers worked, my black ones didn't.
2) If you only need to change filaments at the layer-rate (not multiple colors on same layer), you may be able to get more reliable results by performing the retraction into the Y-device in 2 steps, with a relatively long (about 1 minute) pause in-between.

Now let the rambling begin!
My current goal is to be able to switch filaments a few times per print (basically automating manually pausing the print and manually changing filament). This method is too slow for for fancy multiple colors on the same layer. Why is it so slow? Two reasons. With more time, I can let the filament cool in the lower tube to a known shape and stiffness, so I don't have to figure out how to rapidly move filament back and forth 20cm through 2 couplers, 2 bowden tubes, and 1 Y-piece while it's still hot (though that is my next goal). The other reason is the damn couplers.

Today I Learned that all 4mm tube / 5mm thread pneumatic couplers are not the same (see my photos in the "I Made One" section). I have two of the blue ones and lots of black ones. The blue ones have a larger hole than the black ones (see my photos in the "I Made One" section). I can move recently melted, cooled, and now slightly thicker filament through the large hole in the blue ones, but the filament gets stuck trying to go through the holes in the black onea. Ideally with this Y-piece, you want

  • the inner diameter of the Bowden tube
  • the portion of the inner diameter of the coupler that the filament travels through, and
  • the inner diameter of the portion of the Y-device that the filament travels through
    to all be the same.

If they all have the same inner diameter, then there are no discontinuities that could cause the filament to get stuck on a ridge, etc.

Well the blue couplers seem pretty close (the path is not perfect but the extruder motor seems to be able to push past the minor bumps), but the blacks are too small. And since I only had 2 blues, I had to use 1 black, which meant I couldn't pull the filament out the top of the Y-device. So I'm only pulling the end of the filament up to the top of the Y, just below the metal threads of the coupler. So I have to let the filament cool before it can go there. So it's slow (but still better than waiting until layer 121, pausing, and swapping reels). When I get wider couplers I will pull the end of the filament through them and into the upper tube. Life will be so much nicer...

So I recommend you get couplers with a wider inner diameter.

Now on to the Gcode that makes it work (at least for a Lite6 at 210C with green Hatchbox PLA):

Oh, I made a guess that length of teflon tubing I'd need between my Lite6 and the Y-device, and was accurate to about a mm. Don't know if longer is better or worse, but the Gcode I'm using assumes 0 to 1mm between the two couplers as the closeup photo shows.

; Retraction Code
G91 ; Set to Relative Positioning
G1 E-55 F8000 ; Rapidly pull the filament up to the top of the Lite6. The hot filament is still in the lower Bowden tube, so it will cool to the inner diameter of the tube.
G4 P1000 ; Wait for filament to cool enough that it won't stretch when pulled again. I haven't minimized this wait time yet, but a minute seems to be enough. (Don't worry about it getting stuck - with a Lite6 at least. This is the exact position I retract my filament to after every print - I've never had a problem with it getting stuck, whether the hot end is hot or cold.)
G1 E-55 F500 ; Pull the filament up to just below the coupler for one of the "Y" entrances. Yes it's in the Y-device which is also made of PLA, but since you waited for it to cool earlier, it won't melt the Y-device. The filament stays here until you need it again.
G90 ; Set to Absolute Positioning (if that's what you were using before)

; Insertion code (reinsert filament retracted using the method above)

G1 E120 F800 ; Adjust extrusion distance until filament just starts flowing out.

I'm sure most of those parameters could be adjusted to work better - this is just an example of what is actually working on my system.

OK, that's all I got. I'm exhausted.

Thanks for the Y-device, 3Dator!!!

Thanks a lot for your detailed review!

Very interessting idea to wait for the filament to cool down. I guess this is way more failsave.
With the right material and settings tweaked our GCode also works wonderful but is a lot quicker.

Oh, I definitely eventually want to do it your (the faster) way, I'm just taking baby steps now because the first objects I need to print only need color changes a few times per print, and at layer boundaries. Once that job's done I want get the fast filament changing going.

Thanks again for the design!

nice! Which slicer are you using? Cura is a little dump and uses both colors in every layer even if the layer only contains one color.

I only got as far as testing the Gcode. I usually use Simplify3D and I've heard that can probably support this technique so I'll try S3D first when I get back on this project...

so you have not had any problems with blobs on the end of the filament?
I tried to set something like this up on my printer but it jammed in an instant...

the blobs on the end of the filament are the big problem of this method. For us it worked, after we wrote a custom gcode for the filament change. We pull out the filament just a bit and drive it back into the hotend a little bit after pulling it out completly. This of course works best at a certain temperature, you have to tweak your settings a bit to get it working. Also try some different filaments, they all behave different.
You can find the GCode in our (german) wiki: http://wiki.3dator.com/index.php/Dual_Extruder_single_nozzle

I printed the model and from the looks of it. The bowden tube doesnt go into the Y correct?
Only the filament does.
Also have you had any problems with this wearing out on a print. Since there is hot filament being pull into a printed part on color swap?
It is a nice design and i am going to try to get it working for me thne have plans to get it metal cast. Which should have it lasting a long time.

Yes the bowden tube only goes into the fittings.
At this time we didn't have any issues of the part wearing out even with "weak" pla. When pulled out the filament is still a bit warm and deformable. I guess the part wearing out fast would be the short pfte tube after the hotend.
Thanks, hope you get it working! Would be nice if you add a "make" of your metal cast!

This is excellent! Is it an absolute requirement to have the DRV8825 stepper drive?

Thanks :-)
No, you can use any stepper driver.

I only listed it because we're using those in our printers.

How do i setup Simplify3D to use this one? Im new to dualextrution

Not sure about the workflow in Simplify3D. But you can pick a normal dual extrusion setup guid. The only difference is that there is no offset between both nozzles and you will need our custom Filament switching GCode, that you can find here at the bottom of the page: http://wiki.3dator.com/index.php/Dual_Extruder_single_nozzle

What sized bowden coupler does this use? The caps I tried were a bit too big.

Thanks. I realized that you put it in the documentation and forgot to delete the question. Planning on putting it and your extruders to work as soon as I get the time to work on my printer. s( ^ ‿ ^)-b

At the moment we don't have time to make it work with all fittings. Mabye someone else will do it an upload the design as a remix. We provide the step files on our Github repository: https://github.com/3Dator/3dator/tree/master/step/extruder

With Marlin 1.1.0 (soon to be released) you should enable the SINGLENOZZLE configuration option with #define EXTRUDERS 2. If the GCode contains the needed code to switch the filaments, then no further changes are needed. But it should be possible to add code so that T (toolchange) commands can be used to do the swap. The new Marlin also contains a feature to wipe the nozzle (as on TAZ printers), so you can get cleaner transitions without a "wipe tower."

How many different extruders could you define assuming that the hardware were there to support enough stepper motors for multiple extruders beyond two?


do you guys have some brief instructions on how to assemble the Y piece? thanks

Hi there, just print the part, get yourself the fittings screw them directly into the plastic then connect the bowden tubes as seen in the picture. One of the top tubes goes to your existing extruder the other one to your second one.

Great, thanks. I thought it was also necessary to insert the PTFE tubing inside the Y piece for smooth operation but now I see the model its evident that its should be used without PTFE inside.

one more detail - what feedrate do you use to properly retract the filament during toolchange? the gcode that you describe in your wiki does only contain distances, not feedrates. Did you get this up and running on a all metal hotend or was that a PTFE-hybrid hotend? thanks!

Ah okay, I see. One tiny improvment would be to get rid of the edge on the bottom fitting, just that the filament can't get stuck there.

As retracting speed we use 120mm/sec (very quick). Have a look at the video linked in the thing details. There you can see more details.

At the moment we're using a vulcano clone from china with a PTFE tube inside. I guess it could be difficult with a all metal hotend. Maybe some special coating would work.