Budaschnozzle 2.0 PLA Fix

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scott
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Re: Budaschnozzle 2.0 PLA Fix

Post by scott » Wed Aug 28, 2013 11:49 pm

Because of the low viscosity of PLA at extrusion temperatures it can flow through the nozzle threads and upwards out of the top of the heater block
The recommended PLA fixes have not worked in my case. The PLA is leaking from the top, where the all thread meets the heat sink ceramic-like female fitting.

I used option 3 (teflon on the nozzle threads) before using the printer. Without delay PLA began pooling on top of the heater block, then oozing onto the nozzle and ruining prints.

I removed the nozzle, saw no evidence of PLA on the nozzle threads, but I have been printing with white and maybe I can't see it. After everything was cleaned, teflon applied in multiple layers to the nozzle threads, I reassembled the hot end and reloaded the filament, this time in neon green.

Sure enough, PLA began pooling on the heater block, no evidence of green on the nozzle threads. After removing the all thread from the heat sink I could see the source of the leak, which has been coming down onto the heater block from the heat sink, not from the nozzle threads upwards.

The female heat sink end is gunked with PLA. I cleaned the all thread and tried using teflon tape to seal this connection but the ceramic- like female end just spins in place and I'm afraid of torquing down on this connection and breaking something.

Any suggestions? In my opinion this PLA design/testing/assembly flaw should be grounds for a hot end recall. This really goes beyond a modification or simple fix.

Scott

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Orias
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Re: Budaschnozzle 2.0 PLA Fix

Post by Orias » Thu Aug 29, 2013 7:36 am

The hot end should not be getting hot enough to allow the PLA filament to get hot enough to melt that far up above the nozzle. Are you using a fan when printing with PLA? PLA will hold onto heat remarkably well, it's known as heat creep. The heat from the nozzle will actually travel up the PLA filament. It can lead to jamming if the molten filament cools and sets above the melting chamber. A guide to installing a fan onto your printer can be found here: https://www.lulzbot.com/support/3d-prin ... c-filament If you have any other questions you can always send an email to support@lulzbot.com.

scott
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Re: Budaschnozzle 2.0 PLA Fix

Post by scott » Thu Aug 29, 2013 1:29 pm

Agreed, the hot end should not be allowing heat creep, but it does.

Yes, in fact I installed two fans; one always on directed at the heat sink, and another directed at the print controlled by slicer. With this setup I completed a seven hour print without jamming. Without the fans the extruder would jam around hour two or three.

I see nothing to stop the entire length of all thread from heating to extrusion temp and leaking where it connects to the heat sink. I will try Teflon tape, then liquid thread sealant to stop the leaking.

update: Teflon applied to allthread ABOVE the heater block stopped the leaking.
Attachments
1377804413988.jpg
dual fan, single extruder setup

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Orias
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Re: Budaschnozzle 2.0 PLA Fix

Post by Orias » Wed Sep 04, 2013 6:46 am

Which fan mount did you end up using? Would you mind sharing the model?

scott
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Re: Budaschnozzle 2.0 PLA Fix

Post by scott » Wed Sep 04, 2013 3:13 pm

Sure, the fan mount I designed is attached, notes:

-The 45 degree orientation of the heat sink fan (top) is not ideal; some air blows onto the heater block.

-The print fan (bottom) could probably benefit from a duct, the hot end gradually loses heat and can't maintain temp.

-The chicken and egg irony of printing a pla cooling fan mount in pla. Because the mount contains a long 45 degree overhang my prints repeatedly failed until I wired and hand held the fan with support turned on.

-All my holes required reaming to fit the hardware

EDIT: improved mount design with duct "FANmount2_wDuct.stl" fixes the above problems
Attachments
FANmount2_wDuct.stl
(1.1 MiB) Downloaded 199 times
FANmount2.stl
(813.95 KiB) Downloaded 205 times
Last edited by scott on Wed Sep 11, 2013 2:30 pm, edited 1 time in total.

Tom_Neverwinter
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Re: Budaschnozzle 2.0 PLA Fix

Post by Tom_Neverwinter » Wed Sep 11, 2013 2:15 pm

This is a terribly designed piece.
once any plastic gets on it your screwed.
my thermistor failed attempting to fix leak.
and once the thermistor fails you cannot repair it.

the wiring is crimped together, this is garbage.
impossible to replace or fix without drilling and using pliers on the wiring.
using alligator clips would be much better.

tmoore
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Re: Budaschnozzle 2.0 PLA Fix

Post by tmoore » Sat Feb 01, 2014 9:30 pm

Has anyone thought of or tried a Teflon washer to seal off the nozzle? I thought of machining an oring groove in the nozzle and then using a silicone or Kalrez oring to seal it off.

Update. I just made a Teflon washer and that fixed the drip.

swedenmakesthings
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Re: Budaschnozzle 2.0 PLA Fix

Post by swedenmakesthings » Sat Mar 08, 2014 7:32 am

Check if your nozzle really is tight before your first print, I just started using my spare and I could tighten it 20 deg without problems. And I have no problems with PLA leaking at this point. No tape or anything.

Rickard.

ogrethetoymaker
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Re: Budaschnozzle 2.0 PLA Fix

Post by ogrethetoymaker » Tue Jun 17, 2014 4:07 am

I print with PLA at 206C and have no problems with good fusion in my layers, heater block pooling does occur as it seems, it drips down over my models when printing longer than 3 hours, I suggest simply cleaning this little pool with a Q-tip which absorbs the PLA nicely (when the tip is hot) and then doesn't let it drip down on my models while printing. When I tried printing at lower temps it seemed to not work/extrude as well. I had to mess with the speeds a bit to get the retraction, and varied speeds correct, but now I can reliably print without worry of model print failures, as long as I make my 3-d models printer friendly and wipe up the ooze from the extruder while it prints before it drips down on my models.
Don't Just Wait and trust to fate and say that's how it's meant to be- Don't sell your dreams for small desires- save up and realize your dreams.

Modzer0
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Re: Budaschnozzle 2.0 PLA Fix

Post by Modzer0 » Fri Dec 05, 2014 12:14 am

Had a lot of PLA leakage above the heater block on a Budaschnozzle 2.0 and replaced it with a Budaschnozzle 2.0c as I needed to rebuild the old one and was told the 'c' version fixed the leakage. Well, it didn't and I still have some pooling on the heater block. I'm going to try printing out a cooling nozzle found here viewtopic.php?f=36&t=983 and see how it goes.

Isn't it about time for an all metal extruder path that can handle higher temps? It'll require some active cooling but that's not that much of an issue.

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