Dual Extruders and the TAZ

We’ve have been getting a lot of questions in regards to dual extruders and the LulzBot TAZ. We’ve done some work with a dual extruder setup. Here are some links to some of the work and items. Please keep in mind that it’s still somewhat experimental. I would be interested in hearing about your progress, for I hope to do the same!

Dual extruder mount: http://devel.lulzbot.com/TK-0/TestObjects/dual/double_extruder_mount_2.STL

Reversed Wades: http://devel.lulzbot.com/AO-100/hardware/dual/dual_mount/jonaskuehling_gregs-wade-v3_mirrored_repaired.stl

More links:
HIPS testing for support material: http://devel.lulzbot.com/filament/HIPS/
Dual extruders and the AO-101: https://forum.lulzbot.com/t/dual-extruders-and-the-ao-100/41/1
TAZ testing: http://devel.lulzbot.com/TK-0/TestObjects/dual/

Thanks for starting this.
Dual extruder compatible was one of the main reasons I want the TAZ (and once it is back in stock I shall get one).

But I did get the solid files and have a virtual TAZ, so I can work on the dual extruder. I am not a big fan of having the weight of 2 extruders and hot ends hanging off the front, so I am working on a system with the standard extruder and mount out front, and another (mirrored) extruder mounted off of the back of the X carriage. This should reduce the torquing affect and the x-axis rods, and it also allows for the use of the full x-axis travel.

Y-axis travel is reduced to about 213mm (from 297mm) but the Y axis should be fairly easy to extend. The other issue I see is that an extension will need to be added in order for the x-axis home switch to be tripped and to avoid crashing into the x-axis motor.

couldn’t find the extruder modeled up in anything besides STL, so I drew a basic model myself. Here is a picture of my mock-up.

One big downside of the other extruder on the opposite side of the X axis rods is the large distance between nozzles.

Thinking about just designing a specialty dual extruder that keeps the nozzles as close as possible instead.

You may be able to modify this design to better accommodate 2 Budaschnozzles: http://www.thingiverse.com/thing:34821

not bad, but I would really like to use the same hotend and other hardware that is already on the TAZ, to simplify things.

Thanking about just moving the motor a little (up higher) and then puting 2 extruders as close together as the hot-ends allow.

so the closest the Budeschnozzles can physically be together is 40mm, and this will allow for full axis of the entire build platform if the y axis is extended by only 10mm. 4 simple 5mm shims should allow for that. of course stradleing the x-axis rods is not an option when keeping the nozzles this close.

Here is the latest design. I modified the motor position of the extruders a little so that they could be packed closer together…MAYBE. There still may be some interference with the clamp spring/screw assembly. I also had to rotate them 10 degrees so the motor would not hit the z-axis bearing.

But it does look good so far.

That’s looking pretty good! I like the way the extruders are nestled against each other.

This may involve some extra effort, cash, parts and software tweaking but a rotating head could hold numerous extruders without compromising print area. This could be done horizontally with up to 4 nozzles or vertically (like a ferris wheel) to hold even more than that, however doing it vertically may be difficult to keep print area. Precision would be easy to keep and I think it would be faster for switching between materials. You would need a good feed system for the filament to keep it from getting caught up but that should be a relatively simple fix.

if you add another motor for indexing, you are adding even more weight to the x-carriage. 2 extruders, motors, and hot ends are already pushing the weight limits, not to mention the size constraints. Maybe on a bigger, stiffer machine.

Some other machines use 2 hot ends with one extruder, and just switch between the hot-ends (and filament) by pushing a lever at the extreme ends of the x-axis travel. This would help keep the weight down, but it would have to be very accurate.

Finally was able to order the TAZ and extra hot end and motor yesterday…so hopefully next week I can get this dual extruder project going.

Got the extra hot end, stepper motor, hardware, and hobbed bolt in.

are there any instructions or exploded views of how the extruder goes together. I found a video online, but it seems to be for an older version of the extruder.

This helps some: http://www.plastibot.com/wp-content/uploads/2012/04/Plastibot-Mendel-Instructions-5-Building-the-Extruder.pdf

and this too: http://www.thingiverse.com/thing:18379

I guess the main thing I am stumped on is where that plastic printed washer goes? I cant find it in the instructions of the older models?

Finally got the TAZ in.
Now how do I buy the wires and connectors to hook the second extruder up?
I will play with it with just one extruder for a little while though.

One thing I noticed on the TAZ is that the extruder/hotend holder piece flexes quite a bit, which lowers the nozzle a little, and this will be more of an issue with a second extruder hanging out there. At the least it will have to be adjustable, otherwise the second extruder will drag the plate, and the first will be above the plate.

Lulzbot cannot sell the extra wiring harness (I don’t blame them, they need them for the standard TAZ) so now I am looking for the connectors to make my own.

The wiring that comes with the extra budaschnozzle does have almost all the connectors. just need the male and female 4 pin connectors for the harness to the motor, and the harness to the board (motor connection). as well as the heater to the board connector (wire is included, just not the connector)

I found some of them:

2-pin pluggable terminal blocks (Board to wiring harness for heater) https://ultimachine.com/content/pluggable-terminal-block-2-contacts-508mm-black
Female 2.54mm 1x4 Connector & Positive Latch Housing Kit - 5 pack (board to harness for motor, and harness to motor) https://ultimachine.com/content/254mm-1x4-connector-positive-latch-housing-kit-5-pack

Still missing the Male 2.54mm 1X4 connector & positive latch…Anyone have any links?

It looks like they are the molex SL style http://www.molex.com/molex/products/family?key=sl_connectors&channel=products&chanName=family&pageTitle=Introduction&parentKey=wire_to_wire_connectors

In the past, we’ve gotten a lot of pins & housings from Hansen Hobbies:


That’s perfect, thanks.

Thanks Jebba. I just spent $43 with them. Grr. :slight_smile:


Hi All,

Has anyone had any difficulty with getting the extruders to read out the correct temperature?

After installing the experimental tk-o dual extruder firmware from the devel site on to my taz, pronterface is telling me that T0 is “reading” 120 deg and T1 is “reading” 240 deg. This is while the power is turned off and the heaters are cool to the touch.

I am pretty sure I have wired everything up correctly. I measured the ends of the wires going to the thermistor and they read 100kohm. I double checked that the firmware calls temperature profile #7

Anyone have any thoughts as to what I have done wrong?



where is this experimental dual extruder firmware? I could not find it.

Never mind…think I found it here: http://devel.lulzbot.com/TK-0/software/current/firmware/dual_test/

I just looked at the config file…it seems identical to the config file for the single extruder. Maybe that is the problem you are having.

Looks like configuration_adv.h is the file that enables the second extruder, and that looks correct.

Got some of my dual extruder mount printed, and parts dry fit. still waiting on wires and connectors, but they are on order.

The weight of the second extruder is quite a lot. I think I may make a seperate part to help clamp the extruder mount plate to the X-carriage. That single m3 screw is just not doing it. Still will probably need shims too.

Are you able to upload the firmware and print with dual extrusion. My guess is there might be either something off with my wiring but more likely with the firmware. I am able to more the stepper for both my extruders but cannot try a print with the temperature values being just a little off.