Dual Extruder V2 Heat Block Fan Upgrade

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KelVarnson
Posts: 65
Joined: Thu Dec 03, 2015 10:03 pm

Dual Extruder V2 Heat Block Fan Upgrade

Post by KelVarnson » Thu Apr 28, 2016 9:22 am

Like many here, I was having significant difficulty in getting reliable prints in PLA, due to filament jamming caused by heat creep. After much consultation with others on this forum, and lots of experimentation on my own, I have concluded that the stock miniature blowers are just not adequate. The following upgrade appears to have completely solved my PLA heat creep issue.

I located a 20mm 5V fan that has nearly three times the airflow of the stock blower:

http://www.digikey.com/product-detail/e ... ND/2757793

I designed a shroud to concentrate the airflow on the heat block. I also designed a mounting clip, making it reversible to allow some flexibility in the mounting location. I printed both of these parts in ABS, and here's what they look like, along with the fan:
IMG_1751.JPG
The holes in face of the shroud are sized to be tapped for 2-56 screws.

I added a layer of copper foil on the surface nearest the heater block, just for good measure:
IMG_1757.JPG

Here's how I have them installed on my Dual Head V2:
IMG_1760.JPG
I replaced one of the extruder bolts, the one underneath the stepper motor, using an M4 x 35mm machine screw with a 7mm hex head. This also solves the annoying problem of trying to hold the extruder mounting nut in place during reassembly. Underneath the fan mounting clip is a 6mm tall spacer with a 4mm clearance hole. The screw comes down through the spacer, through the clip, and another nut goes on the end to hold it all together and hold the extruder down. I printed the clip at 100% infill so that it could withstand the force needed for that task.

I had originally intended to place the fans both on the same side of the head, which is why I made the clip reversible. However, I found that it works better for me as shown, with the fans diagonally opposed, mainly because in these locations the shrouds don't interfere with the thermistor wires. In light of this, the clip could be re-designed to make it non-reversible, and extended to eliminate the need for the through-hole spacer. I may get to that...

Everything just barely fits, with very little room to spare! I have not tried, but I believe this design may also work on the single head.

There is about a 2mm gap between the bottom of the shroud (copper foil side) and the top of the heater block. There is no sign of the shrouds melting or discoloring as of yet, after many hours of printing PLA at 205C with a 60C bed. I still need to do a "torture test", setting the nozzles to 240C and the bed to 110C and lowering the head down to the bed and just letting it sit. Hopefully the shrouds will withstand this.

Here's the whole thing put back together:
IMG_1764.JPG
I have attached STL files for both parts.
Attachments
Clip 2016-04-19 01.stl
(25.28 KiB) Downloaded 170 times
Shroud 2016-04-19 01.stl
(80.36 KiB) Downloaded 236 times

kcchen_00
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Joined: Thu Feb 19, 2015 12:42 am

Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by kcchen_00 » Thu Apr 28, 2016 12:20 pm

That looks great. Definitely a mod to help with PLA.

KelVarnson
Posts: 65
Joined: Thu Dec 03, 2015 10:03 pm

Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by KelVarnson » Thu May 05, 2016 11:28 am

I have changed the design of the fan mounting clip slightly. I extended one side of it downwards, eliminating the need for the 4mm through-hole spacer. I also beefed it up just a little bit by increasing the diameter around the 4mm extruder mounting screw.

This clip will now only work on one side of the fan, so on the dual extruder it will require that the two fans be mounted diagonally opposite (as shown in my photos).

I believe this clip will also work on single extruder heads, but I have not yet verified this.

STL file attached. Comments and questions are welcome.
Attachments
Clip 2016-05-05 01.stl
(23.81 KiB) Downloaded 212 times

mrsoft99
Posts: 6
Joined: Sat Dec 26, 2015 8:42 pm

Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by mrsoft99 » Tue May 10, 2016 4:05 pm

(Forgive a maybe silly question please) How do you wire up the 2 new fans?

Each fan in parallel with the existing fan for that head? or in serial?
Or unplug the existing fans and use these instead?

I've been using ABS with my Dual Extruder with good results, but I am ready to try some PLA, and this looks like a very good mod.

Thanks,
Buddy

KelVarnson
Posts: 65
Joined: Thu Dec 03, 2015 10:03 pm

Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by KelVarnson » Tue May 10, 2016 4:42 pm

Remove the existing micro blowers. If you use the fans I recommended, they are 5 volt fans. You can clip the wires from the existing blowers, and then splice the new wires onto them. I am certain the wires from the existing blowers end up in parallel before they get back up to the connector. Just be sure you don't accidentally connect them to the supply wires for the 40mm print cooling fans, those are wired for 24V, and they are switched on and off via the controller. The 5 volts for the extruder micro blowers is always on when the printer is powered up.

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Mizunoslove
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Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by Mizunoslove » Wed Dec 28, 2016 8:50 am

I'm glad I did research here before I tried to design something myself. You just saved me a ton on time. Thanks a lot!

sforeman
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Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by sforeman » Fri Jan 06, 2017 3:27 pm

KelVarnson wrote:I still need to do a "torture test", setting the nozzles to 240C and the bed to 110C and lowering the head down to the bed and just letting it sit. Hopefully the shrouds will withstand this.
Did you end up doing the "torture test"?

I printed out the parts and just I started to assemble the mod. I can't help shake the feeling it will melt with I print ABS + HIPS.

Update: my print from Cura 21 was very thin and weak. Ultimately it failed. I also attempted a "high detail" print and it was the first failed print I've ever had on the TAZ6. I tried Simplify3D and it sliced STL with unwanted gaps along the sides. Would you share your cad files, print settings or the gcode? Thanks

KelVarnson
Posts: 65
Joined: Thu Dec 03, 2015 10:03 pm

Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by KelVarnson » Wed Jan 18, 2017 3:38 pm

I never got around to the torture test. I'm so happy with PLA and the occasional PVA support that I don't even print in ABS anymore, sorry. And unfortunately I did not save the configuration files from when I printed the shroud and the clip. I generally would print ABS at 240 with a 110 bed, though. I don't recall what layer thicknesses I was using or anything like that. Sorry.

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Mizunoslove
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Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by Mizunoslove » Thu Feb 02, 2017 10:48 pm

Well I did the upgrade, but I still get horrible heat creep on the back nozzle. It's pretty frustrating, But at least it was worth a shot.

KelVarnson
Posts: 65
Joined: Thu Dec 03, 2015 10:03 pm

Re: Dual Extruder V2 Heat Block Fan Upgrade

Post by KelVarnson » Mon Feb 06, 2017 6:11 pm

Well that is a drag, and kinda surprising. It cured my heat creep problem 100%, and I use the back nozzle for virtually all of my printing.

Do you have the little fans oriented so that the air blows in against the heatsink?

What brand of filament are you using, and what temperature are you printing at?

I use Verbatim PLA, and print at 205, with the bed at 60.

Also, what print speed do you use? I use 40mm per second. I have no idea what these things are capable of, but that works, so I just leave it alone.

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