Summary

The Lulzbot Taz Dual Extruder V3 is a great tool head. And as long as youuse the Brands of fillament that they suggest you are going to be ok.However, if you want to use PLA from other brands the stock 5v coolingfan on top of the heat sink isn't good enough because it doesn't removethe heat from the critical areas fast enough. This allows heat to creep andcause an extruder jam.

3D Printers > 3D Printers - Upgrades

lulzbottaz lulzbot fanmount fanduct dualextrusion dual

coolingfan cooling

Unassociated tags: heat creep

Category: 3D Printer Parts Print Settings

Printer Brand: LulzBot

Printer: Mini 2

Rafts: Doesn't Matter

Mordiev

Fan Duct for -LulzBot TAZ DualExtruder V3 ToolHead

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updated 14. 2. 2020 | published 14. 2. 2020

3D M

ODEL

ONLY

Supports: No

Resolution: .2 MM

Infill: 20 %

Filament: Hatchbox ABS Black How doesthis mod work?

If you look at this picture you can see that the tubes that hold the filamentare located closer to the center of the heat sink. So that is where the heatwill come from.

The stock fan blows air into this heat sink in the shape of a circle. Meaningmost of the air hits the outsides of the fins that are not that hot to beginwith and then the air escapes out the sides. The center of the heat sinkwhere it is hottest only gets a little air at the bottom and the top. In thepicture the red zones are where the heat will be and where we want toprevent it from staying. The black area is a dead zone where the fan motorsits. So there is virtually no air flow here. The blue zone shows where thefan will blow the most air. A lot of air power just escapes out the sideswithout doing any good.

This fan duct will focus all the air to enter the center of the heat sinkcausing all the air and with it the heat to move safely out to the sides. Thiseven enables us to use two filaments with different heat requirementswithout causing any heat cross contamination. (ie. PLA at 205c and ABS at235c.)

Testing Results

Successful Tests:

Single ExtrusionSeveral materials, PLA, ABS, PVA from several brands at differenttemperatures.Enclosure closed so the environment was warm.High CFM fan with 7.5 V power

Dual ExtrusionPLA and PVA both set to 205c. Hatchbox brandEach one cooling to 175 while idle then heating back to 205 while in use.Enclosure closed so the environment was warm.High CFM fan with 7.5 V power

Dual ExtrusionPLA and PVA both set to 205c. Hatchbox brand

Each one cooling to 175 while idle then heating back to 205 while in use.Enclosure closed so the environment was warm.High CFM Fan on stock 5V power.

Dual ExtrusionPLA and PVA both set to 205c. Hatchbox brandEach one cooling to 175 while idle then heating back to 205 while in use.Enclosure Open for room temperature environment.Stock Fan on 5V power.

Failed Tests :( Heat Creep resulting in an extruder jam

Dual ExtrusionPLA and PVA both set to 205c. Hatchbox brandEach one cooling to 175 while idle then heating back to 205 while in use.Enclosure closed so the environment was warm. (But it worked at roomtemperature. See above)Stock Fan on 5V power.

How to Build Your Own

Credits

I give mad props to Elerosse who designed the first version of a fan ductthat was intended to solve this problem. He has a good description on whyhis design should work. His design has worked for him. It did not work forme maybe because the brand of PLA I am using is more susceptible toheat creep or it may be because my TAZ is encased in a small sounddampening space that also traps a lot of heat. In any case I decided to tryto design my own fan duct to try to solve the problem. His Fan duct ishere. https://www.thingiverse.com/thing:3098955

Props also go to magdong for pointing out that a 5V high CFM fan wouldwork better than the 12V version I originally suggested.

What do you need?

2x 3m screws that are long enough to hold your fan into place. If you areusing the stock fan then you will need screws that are between 10mm and15mmIf you are using an upgraded fan (40x40x28mm) then you need 30mmscrews.

(Optional) Upgraded Fan (Recommended) I say this is optional because Ihave tested using the stock fan and I can get it to work in many situations.It did fail however in situations where there was just too much heat for itto keep up with the cooling. See the above Test Results for more

information. With the upgraded fan I have had much better results even insituations with more heat.

A High CFM fan. Thank you to magdong for suggesting a better choice ofhigh CFM fan. In the comments magdong suggested the... 40x40x28mmSanyo Denki Ace 40, P/N 109P0405H302 (Digikey Part Number 1688-1072-ND)https://www.digikey.com/product-detail/en/109P0405H302/1688-1072-ND

Here is the link to the one I bought and am using. Please note this is a 12volt fan that I am using on the stock 5 volt source. This is the one I usedduring the tests. https://aax-us-east.amazon-adsystem.com/x/c/QmwI3ayY5b55LfK15pyMoawAAAFnDcm5FwEAAAFKAc9fm5E/https://www.amazon.com/gp/product/B073TT83ZN/ref=as\_at/?creativeASIN=B073TT83ZN&linkCode=w61&imprToken=O8RZFxW.5sSTap79rB82Xw&slotNum=0&ie=UTF8&psc=1&tag=tv-auto-20

(Optional) separate power supply. (Not needed for most situations) In mytests the upgraded 12V fan on the stock 5 Volt Power supply movedenough air to prevent a heat creep extruder jam in all but the mostextreme situations. So I think most of you will be fine just using the stock5V power. When I was testing this setup I tested the upgraded fan with thestock 5V power. An external 7.5 volt that moved a lot of air but kept thefan quite enough to live with. And a 12 volt that moved an insane amountof air and sounded like a leaf blower.

Print and assembly instructions

I printed mine using PLA at .2mm. I really don't think it will matter muchwhat you use as long as it can hold the screw threads.

Screw your fan onto the wide mouth end so it will blow air into the funnel.The holes are 3.3 mm so there should be enough plastic inside the holesfor the screws to grab into. If not then you will need to add some nuts tothe back to hold the screws into place.

When you mount this to the heat sink it is EXTREMELY important toposition it so the cooling vent is lined up vertically. Otherwise you willsuffer from more heat creep than before and you will experience morefrequent extruder jams.

If you like this design...

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Thank You

Model Files (.stl, .3mf, .obj, .amf) DOWNLOAD ALL FILES

3.6 MBupdated 14. 2. 2020

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Find source .stl files on Thingiverse.com

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License

This work is licensed under a Creative Commons (4.0 International License)

Attribution

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lulzbot_dual_v3_fan_duct.stl