"Mistral-E" Extruder Cooling Duct

by Leo_N Dec 3, 2018
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When printing with stock fan at 100% I was getting good results. I figured I'd try this, but as soon as I switched I no longer get good bed adhesion on my first layer. Any advice of why this is? Should I reduce fan speed?

Yes. I do my cooling like this:
Example is for PLA
1st layer fan off
2nd layer fan 25%
3rd layer fan 50%
4th layer fan 75%
5th layer fan 100%

I had to cut off the "ears" closest to the extruder but other than that it worked fine.

Could you upload one without the built in support?

Just saw this today, I'm printing it tonight and will post a pic, Thanks for this cooling duct.....!!!

Works perfect on the Ender 5. I've tested it with my warping/curling test and it's awesome. Better than the stock one.

Warping/Curling Test

its weird i have an ender 5 plus and it has mk8 hotend and same set up as ender 5 , but the nozzle is touching the fan duct on one side, and my fan shroud isnt bent its weird , also my stock fan i had to break off the small thin tabs and cut back the raised piece a bit to get it to fit. design looks great id love to use it

also works great for me

Me happy :-)

This works fantastic! I did however have to break off the two innermost tabs on the screw holes since my fan sits completely flush with the side of the hot end cowl, and there's no gap between the ear and the cowl.

Minor inconvenience though once I figured out they were unnecessary on my printer.

This cut down my light stringing to zero. I printed it at .12 layer height, 45mm sec, 205C/60C and 100% infill. An hour later I had an awesome cooling duct that almost looks injection molded.


Glad to read it's working for you as well.

I've tried leveling my be over 5 times now and the print has failed all 5. I'm new to 3D printing anyone got any tips for why my print isnt sticking?

I use the Creality glass bed and have zero problems with adhesion. I just wipe it with alcohol between prints. I will say that the initial bed leveling takes forever, especially with the stock springs. If you haven't upgraded to the yellow springs yet, do it. They make a huge difference.

Also, when leveling the bed the paper should be tight enough between the hot end and the print bed that it almost feels like it could drag the print head. If you can hear it rubbing but the paper still moves fairly easily then it's not tight enough.

I bought my Ender 3 pro from AliExpress and the glass bed i bought though them doesn't seem to work. Even with the bed at its lowest, there still isn't enough clearance between the hot end and printing bed... Is there any way to make the magnetic bed more "Sticky"?

Raise the limit switch attached to the left vertical beam about 1/4", then try leveling the bed again. It worked for me. If the springs are then too loose, lower the switch a bit.

Nicely done. Printed flawlessly, perfect fit on my Ender 3.

Very nice done. One of the best fitting things I've added to my printer.

Wow! just made one!
So simple and elegant and it works.
Tried the water test and it's spot on.

You are welcome.

I haven't printed this yet (all my printers running at the moment) but will soon. I like that you included the supports into the design. We should all get into the habit of doing that as it works so much better than slicer-generated supports.

That is the reason why I included it. It sorta guaranties that the end result of that portion of the duct is the same on every print and not dependent on individual slicer settings.

I went to print this today and noticed the support is not in the file???? Maybe I did something wrong?

I can see that it's clearly shown in the screen shot. If it's not printing then it can only be a problem with slicer settings.

I printed and installed this to replace another design which surrounded the nozzle completely. I was very happy to see this design exposed almost all of the nozzle and had plenty of clearance from the bed on my Ender 3 Pro. An excellent design and a perfect fit. Thanks very much.

You are welcome.

Thanks for creating this. I have not installed it yet (just finished printing) but you can certainly tell when someone makes good designs. This looks very professionally made. Well done!

Thanks. Let us know how it goes.

I have to say this would have to be the most accurate fitting and best designed addition I have downloaded for my Ender 3 Awesome job!

Using this fan for some weeks now and it works very good for such an easy upgrade. Thanks for the design!

You're welcome.

Hello Leo,
I just printed v1.2 of the Mistral E and mounted it on my Ender 3 Pro (from early Dec 2018, has silicone sock). The edge of the duct opposite the vents was lower than the vent end, and contacted the print bed a little before the print nozzle. I used some 180 grit sandpaper and now it clears the bed when the nozzle clears the bed, but I'm a little wary of it touching down if I'm not using my flat glass sheet.

Is the outer edge supposed to be lower? I wonder if my print is warped, or if there is some variation in the height of the print nozzle? I will do a test print end post a make later on.

It should sit parallel to the build plate. Is it possible that the drilled holes are a bit misaligned?

No part the the cooler should be lower than 1mm from the build plate.

One way you could solve the problem is to loosen the two screws holding the fan shroud and moving it upwards. Then re-tighten the screws.

After looking at it some more, the problem was obviously that the fan shroud itself was mounted crooked! I loosened the screws and adjusted the fan shroud so that the lowest point of the mistral clears the bed by 1mm, it is still somewhat crooked and the bottom of the vents are about 2-3mm above the tip of the hot end. I hope this isn't too high, and I end up cooling the hot end!

You don't need to worry about too much air cooling the hot end. It's designed to prevent that as much as possible.

Hi, thanks for this design, just want to confirm that as stock printed - it's about 1mm too low on my Pro, obviously each machine is different but I wondered if you had the version available before you lowered it 1mm?

OK, thanks for the input! Could you make a picture from the front please.

I've edited the Summery and reinstated V1.2 in the file section.

Thanks, Leo, I will print it out and test - then photo the result. Many thanks.

Misunderstanding, I need a photo of version 1.3 mounted.

So will this work with pla or will it melt. All I have is PLA lol

It will work with PLA if you are only going to use temperatures for printing with PLA filament. However over time you will probably have the situation that the tips of the duct will slightly deform upwards. The impact on the function is minimal but I would keep an eye on it.

Thanks I have a silocon sock on so not sure it will last long it hits it. would be nice if it was a little lower to miss it. We will see thank you for the design and reply.

Putting it lower would get the cooling duct even closer to the heat bed and make things worst.

10-4 I just think on mine there looks to be enough room that way it wouldn't be laying on the silcon sock that thing gets way hot lol.

So I printed this, and it has worked extremely well for my purposes. However, I have noticed that when my printer moves to a different spot, it leaves a small dot where the tip moved up. These dots tend to catch on the cooler, and knock over supports mid print. Do you have a source I could use to modify this so that it is about 2mm shorter?

In addition you may also look at "Z hop". I set mine to 0.2mm. With this setting the extruder will raise when moving from one point to the next.

In my opinion it would be better for you work on the source of your problem; getting rid of the "dots".
I believe you need to experiment with your retraction settings as they are probably causing your "dots".
Best you post some pictures on some Ender-3 forum or on Facebook and ask for assistance.

Thank you for the design! I am a big fan of any mod design that is straight to the point, quick to print, and provides noticeable difference in print quality. I was getting ready to print something after installing this mod and running some PLA through to prime the nozzle and this duct launched that filament strand a good distance lol.

Thank you. Very kind words.
This duct might need some minute corrections but I feel it should do fine for most applications. Unfortunately the bottleneck on this printer is the under dimensioned cooling fan.

I have been using the Mistral-E to make chain links and also performed a bridging test. This thing is remarkable for utilizing the limited power of the stock fan to it's fullest.

I'm glad to read it's performing to your expectations. If you haven't already you might want to use version 1.1 as I made subtle changes.