Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

Monoprice Ultimate Blower Duct

by JGTMaker, published

Monoprice Ultimate Blower Duct by JGTMaker Jan 3, 2017


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Fusion 360

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New Easier To Print
It has been TOO LONG in the making, but I have finished an update to the duct work that should solve some of the printing problems that some folks have had with it. It still has good structural form to hold it shape when printing, but now it requires much less bridging to get the print done. You still need to flip it 180 on the X or Y, and print with support from the bed only.

Dual Fan Version
And after promising enough people I would do it, I have done it. There is a dual fan version of the duct and a mounting brace included now. It adds a second 4010 fan. This does not mean I think you need it. In fact I think the single fan version with an upgraded fan is a much better upgrade because of less weight on the print head. However, for those that want more fans Tada! Note the small pegs on the mount line up with the access holes for the linear rod bearings, and there is a little cutout on the inside face that is just the right size for a small 3M Command Strip to fix the brace in place. Good luck, and I would love to see this installed on your printer.

Original Comments
I have seen several dual fan blower assemblies for the Monoprice Ultimate / Wanhao D6, but the all seem to add unnecessary weight. This model is based on some of the ring ducts seen on other printers / extruders. It seems to do a good job without the extra weight.

The one modification I might make would be to slightly increase the diameter of the duct to give the heater block a bit more clearance so that you do not have to print it in ABS (in PLA the heat can cause the outer edge to sag and collide with your prints). Otherwise I am pretty happy with this part.

I have added a new design that increases the ring diameter to 70mm from 60mm. It turns out my concerns about the ring sagging and colliding with the prints were well founded after a couple of days of use. The larger design in PLA is continuing to work well even after a few days of use. The smaller diameter design is still available for those of you willing to print in higher temp material and who want the closer air flow. I continue to be pretty happy with this part.

A third design has been added. This one provides a full ring and a more square-ish ring profile. Both of these features are intended (and are working) to make the ring more stable when things get hot and keep the duct from drooping into the print. Also, to provide a larger cooling area, I removed the directional vents and added lots more outlets. This lets the unit cool an area much larger than just the point of extrusion and seems to work much better.

I will be grateful for your feedback and suggestions.

A quick update is in order. A couple of Thingiverse folks have commented that this part is better when printed "upside down." They are absolutely correct. Turn this over so the fan port is oriented down in your slicer to reduce the amount of support required and to improve the overall print results. Thanks EasySt and others who pointed this out. Your feedback is appreciated.

Print Settings


Monoprice Ultimate





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I printed mine, and when I installed it, one of the corners on my fan, not the duct, broke so it kinda sags on the left side. Nothing a rubber band didn't fix, though. Hoping this improves print quality.

This may not be the place to ask, but I can't find answers elsewhere - I really want to use the dual fan design, but I'm unsure of how to hook up a second fan, just due to not having another place to plug another fan into the printer. is there any good way to do this?

Personally, I don't use the dual fan design. I only created it because so many people were asking for it.
That said, it is my understanding that you can simply create a Y-split on the part fan lead and run it like normal.

Does this result in any loss of print volume?

No impact on print volume at all

I've printed your latest part single version, and it seems to be doing OK. I was having some overhang blobbing issues on some steep angles in a print, and while it didn't fully clear it up, it did significantly reduce the hanging material, at least from what I can tell because it's still printing. I'm only printing PLA, but the shroud hasn't drooped, still plenty of clearance. Still though, I think the solution is simply to make the hollow interior, less hollow. The thicker the walls, the more strength and thermal mass the part has so it will be less likely to droop. For a part this important, using more filament shouldn't be a worry.

I printed it with the screw side down, no supports. There was some minor blobbing on the inside of the screw in area cavity that mounts over the fan, but it wasn't much of an issue for flow, and the other layers bridged all the way across, the rest came out just fine.

hows goes the progress with the dual fan variant design?

The dual fan version just posted. It includes a bit of instruction on how to mount it. Please post a pic if you put it in play. Thanks for the inspiration!

I tried another print today. The issue I'm having is with bridging on the top of the circle part with the holes. If I look in the air holes I can see a lot of strings and in some cases, they droop down and block 1/4 of the hole. I think if this area was rounded inside the print would be cleaner, vs the square nature of the current design. Unfortunately, this is above my pay grade to do the remix :-)

I have posted a new version that should be significantly easier to print. You still need to flip it so the holes are up, and print with supports from the bed only. Good luck. Thanks for the motivation!

Flip it upside down and print with support from the bed only. It's only presented this way on Thingiverse so people can see it in mounting orientation. The instructions on in Thingiverse page goes into good detail about the print orientation and settings. Good luck! Your prints are looking good for doing it the hard way ;-)

I did print it the right way. Flipped it 180 degrees. When I look in the vent holes, the strings from the top bridging hang down. Again, I'm talking about the part as oriented on the bed for printing. The ridges from the strings will divert the flow up away from the bed. I printed on of the full circle remixes and because it was round, it was a perfectly smooth interior. The square shape of this one is tough to get smooth inside.

I see what you are referring to now. Enough folks have had the bridging problem you are describing that I'm going to try to update the vent side surface to be easier to print. I've been thinking about it for a while now. I will try to get it posted this weekend.
Thanks for the feedback and motivation.

This is the best fanduct design on Thingiverse with stock fan. Thank you so much!
I print the MUIIP with ABS, but I need to raise the end from time to time, so it does not bend due to heat.
I can’t print the duct ii design because the reason in the thread above.
Look forward to you updated design!

I've posted a new easier to print version. Give it a go!

Thanks for all your hard work!!!!!

With the existing fan, this duct will give some improvement to your quality.
However, with a higher output fan, you will get even more improvement.
I use this fan with excellent results: https://smile.amazon.com/dp/B01MRBJCTU/ref=cm_sw_r_cp_dp_T1_gTRtzbSNPT2PA

Seems nice, these are 20mm thickness, how do the fit? (since the stock fans are 10mm) I'd say it'd easily go on the top block fan, but wondering about the one below. I wish noctua made 40mm 24v fans, because while mine isn't exactly noisy, it's not exactly quiet either, so I'm looking for a decent replacement. I saved $150 on my Ultimate, so I'm pretty much putting that toward supplies like machine oil, fans, filament, etc. I wanna keep this bad boy tip top.

At newegg, you can actually get some for way cheaper.


these are just 99 cents. Probably no better than what's already in there, but definitely cheap.


this one is a bit more, but still cheaper. Says 8.3cfm, whether that's true or not, that's at least 25 to 50% more than the typical 4-6cfm fans.

I'd really like a completely quiet one though.

I also wonder if you need any specially rated fans? I mean we are talking these fans being very close to high temps.

If you want a cream of the crop fan though...


DELTA is the infamous go to brand for any industrial application. Not known for being quiet though, but they're generally lost lasting well made parts.

This one is listed as a whopping 12cfm.

The fans I linked to are 4010 models. The 20mm thick versions will not work with this duct.

Weird, I could have sworn it said 20mm thickness. Still $14 for a fan is a bit pricey, especially for a potentially no name fan. I'm sure there has to be cheaper.

If you look at this page I think this is the same 4010 model?


And it has a lot of bad reviews.


Here's one that is cheaper, and has [email protected]

It's a 2-pack of high output fans. A bargain at that price.

Potentially true, but if you look at the single review, it literally says that it isn't a 2 pack. Of course they could have just accidentally sent only 1, but I wouldn't count on it, nor would I really want to go through the trouble of explaining to Amazon that I got one of something when I should have gotten 2 of something.

and I quote: "Only received one fan - this is not a two pack even though it is labeled as one. I will revise the review if they send another fan, refund us, or the fans need further review of their performance once installed."

That review was from months ago, and they have not revised it. So maybe they got their 2 fans....maybe they refunded, maybe they didn't even bother.

I figure if you can get a similar CFM fan for cheaper, it would be the better option.

If one were to make a 40mm to 80mm adapter, you could use an 80mm fan like this. Would provide way better cooling and coverage than any 40mm.


I bought this less than a month ago and got two. It is a great fan. Fast, quiet, and moves lots of air. Improved my print quality significantly. Saving the other fan for either the main board or the cold end. I'll probably buy two more and proactively replace both. It will be a good investment in the life of the printer.

Does this work with existing fan or does it required an u fan pgrade?


With the existing fan, this duct will give some improvement to your quality.
However, with a higher output fan, you will get even more improvement.
I use this fan with excellent results: https://smile.amazon.com/dp/B01MRBJCTU/ref=cm_sw_r_cp_dp_T1_gTRtzbSNPT2PA

Thank you and I will look into the fan upgrade but do have another question. I just installed the duct 2(the complete circle vision) and my print start getting very stringy. All setting are the same as before other than the duct upgrade. Do I need to lower the temperate? If so, what all you recommend. Is it normal?


Just got my maker ultimate in, going to print this tomorrow and put it on! Will let you know how it goes!

I hope you enjoy your new printer. Many people have found that this duct with a higher output fan makes a huge improvement in your print quality. Good luck!

also made a huge mistake, printed the shroud in pla, then tried to print with petg at 240, not the best idea but i caught it before it hit the print :P also do you know of any good 40mm fans to replace the stock one with? do they need to be 12v or 24v? Thanks again for this great design!

I tried to use a PLA shroud for a while. No joy!
I recommend printing this part in ABS and adding the silicone boot to your heater for best results.

Reusable mold for silicone boot for Wanhao D6 hotend

Like the noctua 40mm fan? and i did my first benchy in petg without the shroud, running it with same settings with the shroud and already see a massive improvement (way less stringing, better bridging, less glops) so far your fan shroud is rocking even with stock fan!

I'll try to find this fan and compare it to the one I posted above. Please share the link if you have it.

Could I get some measurements to work with? I want to experiment with making a custom version, potentially with much better internal aerodynamics. I tried to overlay some sketches over the model, but it turns out that the model itself isn't exactly 'precise'. For example, if I try to sketch a circle over the inside of the fan shroud, the geometry is actually not a perfect circle, it's not even just offset, it's actually skewed to a somewhat oval shape. The measurements I'd like are the outer perimeter of the fan shroud, the inner diameter of the circle in side of the fan shroud, the screw hole diameter/positions, the height, the inner/outer diameter of the blower part, etc. Basically any measurements that would help. I can do these measurements myself when my printer arrives, but I wanted to get started on making a design before it arrives.

One added note, if you're doing any kind of post tessellation to smooth the model, that could account for the shape imperfections, because some programs actually have a second tessellation option that is labelled "accurate tessellation", which tessellates models while maintaining the integrity of their precise measurements. Without this, normal tessellations can skew models, even if slightly.

It seems you're using Fusion 360 to model with, and if so, then my next guess would be that you're using another program to convert it into an .STL file. My guess is that the program you're using to convert, is what's causing the skewing in the model precision.

If you are using Fusion 360 and would like to share, the file with the sketches alone would be great.

What "internal aerodynamics" are you suggesting?

I put up a 'remix' file of one of my ideas, It'll likely need work, but it'll give you a good idea. May need a bit of a design change to be easier to print and have the correct sizing/clearances for the hotend.

My other idea was for a series of tubes that wrap into a circle, but have their own individual entrance/exit points. Think straws held together in a bundle together. The idea is smaller space = faster air speed, and none of the airflow exit points end up having to lose airflow to each other, and they all get the same intake airflow.

But the bladeless fan style seems like it's probably the best and most efficient way.

I printed "Duct-II" in ABS and it works amazingly well! Finally able to print overhangs, with a certain filament, that I couldn't previously.

Thanks. Glad you like it.
I highly recommend upgrading the part fan to one with higher output. It improved my print quality even more.

Do you have any recommendations at hand?

I also had an idea for a new version of "Duct-II" and I thought I would just put it out there. How about adding round reinforced 6mm holes where we could insert and glue PTFE tube for 2.85mm filament (4mm ID, 6mm OD). In that way you could make the ring a bit bigger, to reduce the risk of sagging, and still be able to get the airflow closer due to PTFE tube being able to withstand higher temperatures. Just an idea. :)

If you don't have time, I might make it myself. It would be awesome if you could provide the step file for "DUCT-II", if possible.

I printed this https://www.thingiverse.com/thing:1363023 yesterday and it came out nearly perfect. I only had minor curling of overhangs. Before installing Duct-II overhangs curled instantly. And alot.

Anyway, I'll stop ranting now. Thanks for this contribution to the D6!

Test your 3D printer! v3
by ctrlV

Made one out of ABS (first time using that material, it worked fine). I like the full ring design. I'm doing a test print now with PLA and it is looking pretty good!! Thanks for doing the hard work.

Glad you like it. Upgrading the fan will make this work even better. Enjoy.

I am a complete noob so bare with me. I am attempting to make the fan duct but every time it gets to the point where it starts the actual ring (base prints fine), it doesn't stick... it just trails along loose and then it all goes bad. I have tried several times. I am using an MP Ultimate to print in its stock form with PLA. Any suggestions?

Bed leveling, bed leveling, bed leveling! I recently got the same machine and had issues until I was able to properly level the bed. Use a business card the first time around (to get approximately 1mm), front, back left, back right, then it wants you to repeat the process with a piece of paper. Use the control knob again on the front of the 3D printer to adjust the height (I mistakenly tried adjusting the bed's spring knob on the front the second time around, when you're supposed to use a piece of paper, and kept having print issues). Then calibrate the back left and the back right, using the spring knobs.

There are pretty detailed print process instructions in the description and the print settings info on the thing docs. The basics are you will need supports generated from the bed and your results will improve if you flip the duct 180 degrees on either the x or y axis in your slicer. You want the fan intake pointing down. You want supports from the bed only. If it prints internal supports they will be almost impossible to remove. Finally, PLA can be a problem because it can sag when using the duct so close to the print head heater block. ABS is a more effective choice. Good luck. Let me know how it goes

I'd like to echo budhartel's request below. It would be effective, I suspect, to add a modified version of your ring design that would accept a second fan on the other side.

As Bud indicates, it could be supported by something like this: http://www.thingiverse.com/thing:1875511

And with that, we might even be able to top it with one of these nice 20mm tall velocity stacks: http://www.thingiverse.com/thing:2211722

By the way, I've been replacing my fans with these excellent ball bearing high velocity fans from Amazon: http://a.co/7N3anH0
Save your old plugs and wires. These don't come with plugs, and the wires run a bit on the short side. If you don't care to hassle with soldering on your old wires with their plugs, these are also nice, when available: http://a.co/hD78TvS

Wanhao D6 Left Fan Mount With Slide On Nozzle - Top Fixing
Velocity Stack and Fan Guard for 40mm Fan (flat side)

Looks good - considering trying this - I assume it would have to have internal supports? If so would they be easily removable or not?

Internal support would be nearly impossible to remove. Make sure you are using a setup that can bridge 6-8mm effectively and you will have much better success.
That said I have an idea to modify the design that should improve results with less support/bridging requirements. I'll try to put it up soon.
Thanks for the feedback.

I love this design. PLA printed ok.

But print quality is bad with stock fan and this blower duct. Tested with Marvin keychain (is ugly). tested with fan at 100%, 60 % and 0%

If this is your only source of cooling, you will still have to print pretty slow to get good results in PLA. I've been looking for a high output 40mm fan that will not create too much noise to enhance the results with this ring. Good luck with Marvin.

The full ring design is a really nice improvement over the stock cooling. The only suggestion I have is that the walls of the ring seem to be unnecessarily thin. Do you think you could upload a version with thicker walls? Otherwise, fantastic job! Can't wait to try future revisions!

Sounds like a reasonable idea for a try. I'll definitely post one.

My original thinking was to keep all the weight off that I could, but I don't think adding a little more to the walls would have any significant impact.

I'm also wanting to post one with a sloped bottom around the ring to reduce the unsupported bridging that it takes to print now.

Thanks for the feedback and good suggestion.

I love the full ring design, and submitted a "Made One" for it.

It's working flawlessly! (But see my "Made One" notes.)

I found it best to rotate the design upside down for printing, first.


I agree. Printing this inverted is a great processing improvement. Thanks for the feedback!

Love this design. Would love to make a remix to add a second fan to the opposite side and support the second fan like this design: http://www.thingiverse.com/thing:1875511

I am a total beginner in 3D design. I was wondering what you designed in, I have been playing with tinkercad but realize that may not be sufficient. If i was to remix this design, would you be willing to let me start with your source file?

I would think this design with a fin attached to it on either side would be all the cooling you need and the fans could be standard and control from the same power source on the printer through a "Y" connect.

Wanhao D6 Left Fan Mount With Slide On Nozzle - Top Fixing

I would gladly include my source file from Fusion 360. However, I think the extra fan on the opposite side without some kind of support would be a weight problem. As soon as the unit got up to temp the new fan would sag and crash into your prints. But the file is included if you want.

Also, I am uploading a new design that seems to work somewhat better. I would love your continued feedback.

Thanks, I like the latest modification, I look forward to getting this printed out. I agree with your comment about the second fan needing support. I hope to add that support using the Left Fan Mount in http://www.thingiverse.com/thing:1875511 .

I may start by just printing out you latest design in PETG. Then I may start playing with a second fan remix.

Thanks for the work you put into this and sharing it!

Wanhao D6 Left Fan Mount With Slide On Nozzle - Top Fixing

If you get a second fan remix working with that support, I'd love to see it!

Is this using the stockfan or do I have to purchase another one? Because I'm thinking of buying a Wanhao D6 but I heard the cooling sucks, and I want to find a fast and easy solution and this seams to be perfect (I have not much experience when it comes to 3D-printer modding ;) )

This duct assembly (and an updated model I will post soon) use the stock fan.

I am considering creating a new model that uses an aftermarket blower instead of the fan to increase total airflow, but these improvements are proving to be sufficient.

Also, these things were more or less made to be modded. Don't hesitate to give yourself the chance to gain some of that experience. We all started with zero!

Thank you verry much for the fast answer ;)

Comments deleted.

My Man! I was just settling in to design one of these tonight, and I thought, "Maybe someone has put one up online in the past week or so..."
Thanks for that.
Uniform cooling angles are the only thing I find lacking with the MUIIP so far. And the weird filament spindle that ships with it...


Thanks bbernardy!

Let me know how it works for you. Especially if you have trouble with the outside edge of the ring sagging. I'm thinking of adding a support that connects this edge to the cold end block if needed.

So the enclosed ring design was working great for a few days until the heated bed plug came half undone and it was printing at max temp for the bed ... This warped the part and it started to make prints fail by ramming into the bed.
I am going to print this out in PETG and see how it holds up.