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Dual parking carriage extruder Prusa i3 | E3D & 1730 FMH

by Helix3D Mar 26, 2017
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not sure, but seems that 10 x lm8uu needed instead of long version (2 for middle & 4 for each side), or 2 x lm8uu + 4 x lm8luu. is it correct?

Correct, 10x LM8UU in total

Any chance you can post source files or send them in private?

I use french english translator.
Before embarking on this beautiful experience, I just tested 2 electromagnets but if they remain powered, they heat a lot. How are they cooled?
Thank you

managed to overcome the issue? also just thought to comment here: my electromagnets do heat up (also voltge and current flow) but do not magnetize - only a little...not even close to 2.5kg

mastercraft. amazing scheme!

Hey, I was wondering if have ever tested the repeatability of the electromagnets? What kind of accuracy are you able to achieve?

try activating a g26 mesh validation tool

I'm starting a remix of this system using 30mm heatsink cooling fans, a 5015 blower through the center carrier for print cooling, and permanent magnets for the printhead exchange system as used by halentech's remix, in an attempt to reduce the bulk a bit. I'll try to keep it compatible with the existing left/right z-slide for ease of switching, if anyone is interested. It'll be a while before it's ready. I do really like your system as is, but I want to try my hand at redesigning. I'll post a link here once I get the basics sorted out, and of course provide the link back to your system.

how do you mount the electromagnets?

There are 3 mounting holes for M3 socket head screws for each electromagnet.

got it. mine only had a center mount hole that i had to drill out. what did you use for the metal "pegs" that hold the two carriages together when they connect?

I guess you mean the pins that Jellebross uses? I used normal Ø5mm stainless steel round stock for that. However they aren't really needed in combination with acceptable quality shafts and bearings.

sounds good bud thanks

Hi, i also implemented this approach but im having trouble with bed leveling. Auto bed leveling is not working right because my left extruder is hitting the x endstop. When i move it and free up my x endstop, it performs correctly. Did you manage to do bedleveling with x endstop is pressed? Tnx!

You can change your measuring points in the firmware. Can you adjust it to where the carriage isn't pushed into the endstop?

Hmm.. make sense. I'll try that. Thanks!

Hmm.. though.. just realized it. The left extruder is left parked and when the xcarriage do the leveling. Did you do the same thing?

Indeed, you can change the measuring coordinates in firmware and latch the left extruder while performing auto bed leveling.

Hi, thanks for the response. Just a question. Did you use magnets to hold the left and right extruder when parking? Or you are just dependent on the x coordinates that you put in the firmware were the left and right extruders be left during operation of left and right extruders?

Hi Alex,
Neodymium magnets keep the carriage in place when parked. (Pulling force of the neodymium magnet must be less than that of the electromagnet)

Yes of course. When im bedleveling. I keep the hot end parked that is why it is pressing the x endstop. So you do bedleveling with the extruder? Can you do bed leveling with the extruder parked and pressing the x endstop?

Hi, any comments on this one?

Hi Alex,
Sorry, completely forgot to answer.
When homing or bed leveling, the extruder on the X-axis endstop side needs to be connected to
the middle carriage (electromagnet on, not parked). In the start gcode, put M42 P[pinnr] S0 before G28/G29 and
adjust the extruder offset and G29 grid/measuring points in the firmware.
Hope this helps.

Hello, please can you post more details about connecting of relay board to printer board? To which connector do you connect relay board? I have MKS integrated arduino board and I dont exactly understand where to connect relay board. Also I have repetier host with slic3r and I want to be sure about commands to change hotends. Please let me know your knowledge.

Thank you jan

Hi Jan,

You can connect the input pins from the relay board to free aux pins (analog or digital) on your MKS-board. (or other Ramps equiv. board) Any free pin (40,42,44,59,63,64,65,66) will work. (49-53 are probably connected to an LCD). With an M42 P[pin nr.] S[0-255] command in Gcode you can turn on/off the relay.

I don't know how to use slic3r with this. 3D-proto has a custom Perl script for this, but he hasn't made it available publicly.
Simplify3D and Cura 15.04 do work. (see description)

Hello, please could you post hotend left end right for e3d - sources or good stl files? STL files are corrupted and cannot be edited. I need to do some modification for longer hotend.

Hi Jan,

What files do you need? The stl files aren't corrupted as far as I'm aware.

Hello, I am using freeCAD for editing stl files and I have problems to convert stl files for left and right E3D hotend to editable object. I need to modify it because I am using j-head V6 hotend clone. So best for me if I can get left end right files not in stl but in some cad editable format.


Hi Jan,
I've uploaded STEP-files.

Thanks a lot! It will be now more easy to modify hotends for j-head types. After I finish the construction, I will post a remix of your project. Thank you again!

Hello, I am preparing to build this project. I will use combination of your V6 extruders and center cariage + L and R Z axes from original project. I did some measurements and it should work together. Also I modified center cariage for box proximity sensor. Maybe I will post third remix of original project.

How do you solve dual fan protector for both fans? Do you printed own or use metal? As show on renders, there are some dual - metal fans protectors...


Hi Jan,

I 3D-printed the fan protector just like the other parts.
Good luck with the build!

very nice design you made here. I really want to try this design out in my next printer. Some questions and comments for the parts:

  1. Is the 1 Screw holding mechanism really enough to hold the hotend tight and in a correct angle? I am not really sure if that is the best design. Why not design a clamp mechanism from the side of the fans? So you can clamp the hotend and screw it down with screws and nuts from the "fan side". Maybe design it with some long holes so you are still able to adjust the nozzle height.

  2. Why are the fan shroud and the hotend mount not one part? If I see it correctly out of you drawing you used a fan cover to connect the fan shroud and hotend mount. I think one unit would be a much sturdier and simple solution. And as a plus you are not limited to the not so common 40mm x 7mm fan.

  3. Do you know how much this setup reduces your build space in X direction? I am just curious cause I will design my new printer from scratch and I would accomodate for that "loss".

Hello Chris,

  • The clamp idea for mounting the hotend is indeed a good idea, though more printed parts and screws etc are needed and the adjustment length will probably be shorter. But good ideas are always welcome. The downside of the current design is that the mounting hole needs to be printed contrentic and within tolerance. However I've been using it as is, without any problems for almost a year now.
    As for the clamping force, 15mm plastic M4 thread should be more then enough.

  • The part cooling fan duct is a seperate part because it's easier to print. Otherwise it couldn't be printed without supports. Plus, it's easier to replace it with a custom one. (The part cooling fan duct is also directly connected to the main part with screws.)

  • Depends on the x-axis carriers and placement of the bed. On a regular i3 it's about 55mm.

hmmm nice job i think someone to build this setup??i read all of that to you wtite and i believe is working

would it be possible to put online the other side of the support e3dv6 because I would like to adapt your system to 2 e3dv6.
I try to mirror the existing piece but the support of the 20mm plate is not in the right place.
thank you for help

Hi Kasper,

What exactly do you mean with 'the other side of the support e3dv6' and 20mm plate?

if you make a mirror of this piece "left-extruder-e3d.stl" the position of the 20 mm circle facing the electromagnet is not correctly arranged.

Ah, I see. I actually don't have a right carrier for an E3D v6, but I can make one if you want.
Let me know. Probably more people are looking for this.

if you could do it I'm a taker and can be a lot of people too because the 1730 is too expensive as I read below.

I've uploaded the right E3D carrier, see 'Thing Files' tab.

has this fixture been tested by anyone?
If however you have a complement of information in addition to Jellebross and 3d proto I take them too.

thank you for your work

What would the tool change script be for Slic3r ?

how can I set the Z offset of the two nozzles?

Hi Klippi,
Both extruder carriages have set screws on the back to adjust the hot end height.

Thank you. there is also a possibility to adjust it in the firmware

Will this work with 2 e3d V6? The 1730 is expensive and I'd rather use a cheap V6 clone

unfortunately, the 1730 and E3D V6 are different heights, however the mounting diameters are the same. You could problably get away with modding the 1730 carriage stl. Or mirroring the E3D carriage and adjusting the magnet plate.

Hi. Is it possible for you to provide the solidworks project?

How much x axis do you loose with this setup please?

About 55mm. But that depends a lot on your printer.

I haven't tried to print this yet but did check out how it sliced and noticed something about the Right-Extruder-1730 part. It seems to slice a hole on the outer ridge across from the Fan for hotend. I think the model is too thin there. In Slic3r it shows that area as pink in object placement and when sliced it makes a hole. It would probably help to thicken the inner area of that chamber.

I've checked it and indeed Slic3r generates a gap. I've printed these with Catalyst ex without any problems. Cura also seems to work fine.
But yes, I'll probably thicken the wall.

Comments deleted.

Really cool design!
How about changing the part cooling fan to be a blowing fan 5015? Much better for pushing air..

We've tried that but as a result, the carriage becomes a lot bigger. Since the i3 already doesn't have much X-axis distance, we've opted for the 4040 fans.

Anyone tried this?