Consistence Nozzle and heat break, block, blob issue  

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muo
 muo
(@muo)
Estimable Member

I keep having issues where the nozzle/heatbreak gets loose from the heat break and sometime blobs form up on the nozzle area or on top of the heat block, i have been having this issues for a many Months now after dis-assembling and re-assembling the hot end many many many times. here is what i tried to fix the issue to no avail

-re-assembled many times
-got a adjustable torque wrench and used that (3-2.5Nm) different articles vary a bit on the torque needed 
-gotten a new heat block and heat break and installed those
-also put carpet under the table(4-wheelon table) to try and reduce vibrations from the printer causing nozzle/heatbreak loosening
-also completely remove(Burn) filament stuck on/in nozzle/heat break/block before reassembling

Any help would be apricated its at a point where its getting ridiculous with this constant blob issues….

so if you can help me answer this questions below or any advice would be great…….

1) I have a tungsten nozzle could the efficient temp usage with that material cause nozzle to become loose over time vs a brass nozzle?

2) should I put the printer on carpet directly or on a table with home leg support to the ground if there are vibration issues?

3) How close do you have to be the right torque amount to get a good seal between the nozzle and heat break 3-2.5Nm, between that ok or do I have to be exact on 3Nm?

4) When hot tightening  do I have to make sure there is 0 movement or can there be just vary small amount of wiggle back and forth few mm?

5) also I had to get a new heat cartage old one broke, when hot tightening the temp does dip down down to 250 sometimes and sometimes 260 I am not sure if the temp drop is causing not so good seal?

6) IF your Z is to close to the bed can the filament more up the nozzle or over the nozzle to get inside the gap between nozzle and heat block and slowly loosen the nozzle?

7) are we suppose to hot tighten slowly for a reason? Or can we do it quick if we use a adjustable torque wrench?

8) if for some reason where the heat sink and heat break loose a bit can that cause issue?

9) Can Printing mostly with PETG cause this issue?

10) Don’t think to but Can bad Filament cause the nozzle/heatbreak to lose?

Posted : 12/04/2020 10:31 pm
Skia
 Skia
(@skia)
Active Member

Too bad you didn't get an answer, jet.

I ran into the same issue. I disassembled, cleaned and retigthened a few times now and thought I'd overcome it, but my print has blobs all over it after printing overnight, again.

I am confused that you still have the issue after exchanging the parts, that was supposed to be my plan b.

Have you made any progress in the meantime?

Posted : 10/05/2021 6:15 am
Skia
 Skia
(@skia)
Active Member

Also just a thought about filemts: it got way worse for me when I switched to PETG, so I suppose it has to do with the higher printing  temperature.

Posted : 10/05/2021 6:17 am
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(@)
Illustrious Member

Read this guide, then reassemble your hot end following it to the letter. 

https://e3d-online.dozuki.com/Guide/V6+Assembly/6

Posted : 10/05/2021 7:39 am
JoanTabb
(@joantabb)
Moderator

This image might help you understand the assembly information.

when assembling the hot end there are three places where you can get wiggle
1, if the nozzle is assembled incorrectly, (Left image above) the Heatbreak will be free to rotate in the heatblock.    I use a small socket spanner, like this
the large end is a 7mm socket (intended for tightening wheel nuts on radio controlled cars) and the small ears, allow you to exert just enough effort to tighten the nozzle, when using your fingers on the spanner...

2, if the heatbreak is not firmly screwed into the cold end heatsink, the Nozzle, heatbreak, heatblock, heater and thermistor assembly will be free to  rotate in the cold end heatsink, (the Finned aluminium part) (Make sure the heatsink is firmly screwed on, by hand, no need for tools as you risk breaking the neck of the heatbreak)

3, if the extruder housing is not assembled tight, or there is a poor fit between the top of the aluminium heatsink and the plastic parts of the extruder housing, then the whole hot end assembly will be able to rotate in the housing...    some people have stretched a small elastic band around the top of the aluminium heatsink, in the mounting groove, in order to reduce any looseness here

 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 10/05/2021 11:06 am
cwbullet
(@cwbullet)
Illustrious Member

@joantabb

I have good success with these:

https://www.ebay.com/itm/174559099617

--------------------
Chuck H
3D Printer Review Blog...
Posted : 10/05/2021 5:06 pm
cwbullet
(@cwbullet)
Illustrious Member

Shop around - you can find them much cheaper.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 10/05/2021 5:07 pm
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(@)
Illustrious Member

Posted : 10/05/2021 5:10 pm
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