Lulzbot TAZ Dual Extruder Fan Mount

Hi Lulzbot Users!

With the release of our overwhelmingly exciting Dual Extruder, one of the biggest questions everyone has is, “Where are the fans?!” Well, the original design did not take fans into account, so I’ve been working on a design fusing Lulzbot’s lower bracket for the dual extruder ( with American3dPrinting’s dual-duct fan mount (, and the result is the Dually Cooly
2014-11-20 Dually Cooly 8.stl (1.34 MB)

Simply replacing the standard lower bracket, the DC allows you to attach two standard 40mm 24v fans, one for each extruder, that blow air to the heat sinks and also to the nozzles as they print. This has the most impact when printing with PLA, which otherwise can be a challenge due to heat creep and surface cooling issues. The DC will also aid in printing with HIPS, T-glase, and other materials that do well with some cooling during printing.

The DC prints sitting flat and needs no support, thanks to the two vertical supports inside the fan mounts. Holes on the top of the E0 fan shroud allow you to insert the whole M3 screw down into the holes and through to their mounting points on the Dual Mount bracket. Sizing of the holes on the fan mounts are ideal for heat inserts that you mount the fans to, but with some acetone to adjust the holes you can self-tap some M3 screws in. Perhaps a second design for self-tapping would be helpful.

This is my eighth iteration of the Dually Cooly, and there are still many improvements to be made. I appreciate any and all feedback and testing.

This is awesome! Thanks for your hard work.

Do you think you could have another version that still has both fan mounts but only one is pointing at the tip of the nozzle and the other is only for cooling the fins on the buda. My thought is one side for pla and the other for abs/flexy/nylon.

Just a thought.

Hi smiley! An interesting thought, and totally doable. Do you know how well PLA bonds with abs/flexy/nylon in dual extrusion prints? Because of the difference in material and the big temperature differential, I wonder how well they will adhere to one another. I haven’t tried it yet, so I’m wondering if you have any experience in that. Thanks!

New design! Dually Cooly 9 features:
-larger support fins inside the two fan shrouds.
-cut back bottom fan shrouds for improved bed clearance and nozzle clearance.
-indentation on back of bracket to make room for carriage screws.
-larger M3 screw insertion holes on rear nozzle.
Let me know how this works for everyone!
2014-12-2 Dually Cooly 9.stl (1.31 MB)

Had some trouble printing DuallyCooly9. Made further improvements for DuallyCooly10 including:
-Stronger back fan mount for printing and installing.
-Smaller holes on fan mounts for self-tapping M3 screw installation
-Fixed previous holes on front fan shroud.
2014-12-2 Dually Cooly 10.stl (1.45 MB)

A quick followup note regarding dual fan control. Use this updated Dual Extruder Firmware:

Then to control Fan one you continue to use

M106 Sxxx

, and to control Fan 2 use

M106 P1 Sxxx




In my experience pla and abs dont bond very well due to the temperature difference. My real motivation was to have ABS and Ninja flex printed together. Since the nozzles are so close the radiant heating tends to get the budda cooling fins a bit too hot and thus causing extrusion jams. So the though was to have one fan mount with just the upper cooling to keep the budda happy because the tip cooling isnt needed with abs. The other mount would have both if I ever want to swap in pla.

I printed out your version 8 and love it. I just have tape covering up the nozzle cooling when printing ninja and abs. Is the latest version worth the upgrade?

Thanks again.

Printed a couple yesterday, and they turned out great.

One question - anyone figured out how to get the brass bushing from the levelers out of the front of the old dual extruder plate without destroying it (or know of a quick source to buy a replacement?)

Ditto on 3driffs questions about the brass bushing on the leveler.

Also, is the x carriage starting to get weighted a little heavy now with all that hardware mounted to it. I’m running my dually at 60 on the perimeter with successful decent looking prints. Any opinion on whether I’ll need to back off the speed with the addition of these dual fans to maintain decent print quality ?

Thanks for making this awesome part! Can you share what print settings you have used to get the best results? I just printed it in ABS (.50 nozzle, 20% infill, .37 layer height, 230/93 degrees) and it bowed/warped to the point that I don’t think I can use it. Other than the warping it came out very good.

I assumed ABS would be best for durability, but maybe I’ll have to do a bigger part like that with PLA. I printed it on blue painter’s tape because my PET was a bit marred, so maybe that’s part of the problem and I should just put down a new sheet of PET and use a glue stick. Any advice is appreciated!


I printed a couple at 50% infill, using the Cura ABS Medium profile, and they came out without warping. My local “has everything” hardware store had all the screws I needed to install everything, and an M5 barbed socket that I used (after removing the barbs) to glue in for the spreader thumbscrew.

Just a bit of feedback on the design - the fans strike the right side build plate clamps (don’t try to print the bed calibration!). It looks like the fan mounts could be shifted up (and the ducts at an angle) by about a half inch, which will let everything clear.

And I’m definitely getting sag in the center now, so it’s a bit of a fiddling game to get the z-home set just right (so it’s not too squished in the middle, and not too much gap on the edges. Anyone have a 4 rod mod for the X-Axis? :slight_smile:

Now to figure out how to get Cura to turn on my HIPS fan, but not my ABS fan…ah, such fun!

Hello 3dRiffs, are you saying the added weight of the Dually Cooly added enough more weight to the X-carriage to cause a dip in the middle of the X-carriage when the extruders are X-center?

Edit: I think the dual extruder weight itself can cause a little dip in the middle of the x-carriage w/ out the fans, but it sound like the fans added to the dip? Is that your take on it?

I’m pretty confident that the dual extruder causes a bit of sag on the x-axis - on an x-home I can watch the gap shrink to the middle, then grow again to the other side. I’ve started z-homing about halfway from x-home to the center of the build plate to find a Goldilocks gap - not too thin (middle), not too thick (edge) so I can do big prints.

With the dual fans, I have an impression/suspicion that the off-center weight on the extruder plate causes an uneven sag (rather than the maximum sag in the dead center of the build plate, it’s offset to the right a bit). Haven’t been able to confirm it yet - that’s a project for another weekend (printing stuff for Christmas today). It’s equally possible that I didn’t print my dually coolly with the right settings and it’s bending and flexing.

Please keep in mind that we’re talking fractions of a millimeter for all these “gaps”. I’m trying to print dual extrusion model with significant support (think a starship floating above a bed of HIPS support material), so it’s really sensitive to z-axis issues.

Hi all!

Have another user who has flashed the dual fan control firmware and both fan commands (with and without the P1) activate the first fan only, while nothing activates the second. Has anyone had the same issue? The firmware works beautifully on mine, so I can’t reproduce the issue.


In reply to a few comments/questions:

I printed the Dually Cooly with a .5mm nozzle and a .4mm layer height using Lulzbot ABS. Wide brim to prevent corners peeling up/warping. I used 80% infill, which is the standard for Lulzbot printed parts. Cura config attached.

In If you want to remove the heat insert for the screws, use a hot soldering iron to warm the heat inserts and pull them out. They stay hot for a while, so always be careful. Don’t twist them when you insert them, but go straight into the hole in the ABS.

Printing Ninjaflex and ABS is a great idea, and something I have done several times with great results. Ninjaflex with Laywood was super fun, and a nice help to have the fan.

Related to the sag in the center of the X-axis, I have heard some reports of this, but have not had that difficulty myself. I do know that the dual extruder toolhead does add significant weight to the X-axis, and that must be taken into account when setting print speeds. I typically keep my dual extruder printing speeds down to 30mm/s or so, but a little higher shouldn’t degrade quality too much at all.
DuallyCooly.ini (10.6 KB)

Thanks for all that great information. How do you like printing w/ a 0.5 mm nozzle? Do you see a noticeable difference in the quality of the print vs a 0.35 mm nozzle? If you were printing something as a gift or for a customer vs something for your printer would you chose one nozzle size over the other?

0.5 mm nozzle s/ build the part faster than a 0.35 mm nozzle; hence the reason for my question.

In my experience, .5mm nozzles are less hassle than the .35, and of course print much faster. Being a person who likes to print a lot, fast, and large, I stick with the .5 almost always. I have not seen a significant difference in print quality unless you are printing very small, very detailed parts. I also am not very bothered by visible layers, and find that they add character to what you know is a printed part, so it is nice to be able to print .4mm layers with the .5mm nozzle.

I started designing one before I found this, but this design far beats my design! Thanks!!

One suggestion or perhaps I can pitch in some of my time to do this. It would be nice to be able to print this design without a need for support material. Something like having the two fan mounts screw or snap into the rest of the bottom carraige. Thus 3 seperate prints to be done, and a tiny bit of assembly.

I have yet to print the Fan Mount so I certainly would also like to see a snap on or screw in version because I will be doing this soon; however I’m assuming it was done the way it was for strength purposes.

If it can be made sufficiently strong as a snap on / screw in part then I’d really like to see that.

Awesome! Thank you so much for this important improvement. We have had no issues with ABS, Ninjaflex, HIPS, Nylon, PET or PVA, but the heat creep on PLA makes it VERY difficult to build successfully with our Dually. :smiley: