Leaky Hotend  

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noah.s10
(@noah-s10)
Active Member

After printing with a .8mm nozzle I swapped back to my stock .4mm and ever since I've had filament leaking out the top end of the heat block and from the threads of the nozzle.  This is very problematic as I have to pause the printer and clean it every hour to avoid a bubble of material falling on my print and ruining it. Everything is original MK3S and I'm using the latest version of prusa slicer. I've tried tightening everything. What can I do? Would buying a new nozzle help? Do I have to take out the hotend and clean it? 

Best Answer by Tim:

Guy's post is in this thread:

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-general-discussion-announcements-and-releases/leaking-nozzle-heat-block/#post-156624

Copied without permission:

1. Cut zip locks that hold your heater wires or you may run out of slack

2. Heat to filament temperature and unload filament. Remove fan shroud shift parts cooling fan aside.

3. Increase temp to 285C

4. Use wrench to hold heat block in place

5. Unscrew nozzle completely.

6. Reach into empty nozzle hole and clean out old filament debris with counterclockwise twisting of q-tip.

7. Use wrench to twist heat block 45 degree onto the heat break. (viewed from bottom would be clockwise.) This should advance heat break a little further into heat block.  

8. Hold heat block in its temporary 45 degree position with wrench

9. Install nozzle. It should now impinge against end of heat break a bit sooner. Tension to two fingers tight (still at 285C)

10. Let nozzle temp cool

11. Turn off printer

12. Undo hot end cover and straighten out the entire E3d hotend assembly to bring heat block back into normal alignment. The entire assembly including the cooling fins should be rotated, not just the heat block.

13. Redo zip ties.

Posted : 12/08/2019 8:54 pm
Tim
(@tim-m30)
Illustrious Member

If you didn't use the E3D-V6 assembly guide when replacing the nozzle, or properly interpret the Prusa instructions for twisting the heater block 45 degrees, you probably haven't properly tightened the heat break to the nozzle. And it will leak.

 

ps: I really hate spell check and auto correct ...

This post was modified 11 months ago 2 times by Tim
It is always wise to get more than one opinion......
Posted : 12/08/2019 9:12 pm
gnat
 gnat
(@gnat)
Prominent Member
Posted by: Tim

If you didn't use the E3D-V6 assembly guide when replacing the nozzle, or properly interpret the Prusa instructions for twisting the heater block 45 degrees, you probably haven't properly tightened the heat break to the nozzle. And it will leak.

 

ps: I really hate spell check and auto correct ...

Wait, so this wasn't a a problem then?

For what should be a simple procedure, there is sure a lot that can go pear shaped about a nozzle change 🙁 

I agree with Tim that the root cause is that the nozzle and heat break aren't properly mated. You'll probably need to do a full tear down of the hot end to fix this properly as the plastic that is already in there is going to keep it from letting you getting it properly snug.

Regardless of what you do, however, be very careful trying to remove the nozzle or heat break until you do take it apart to clean it up or replace the parts. The above was due to a stuck nozzle and the wrench holding the block slipping off.

MMU tips and troubleshooting...
Posted : 12/08/2019 9:33 pm
Tim
(@tim-m30)
Illustrious Member

And just in case it isn't obvious, the image Gnat posted shows a bent heat break.  One of the reasons the hot end is heated to 285c per the assembly instructions any time you loosen or tighten the nozzle to the heat break (it is NOT tightened to the heater block).  Guy recently posted a procedure that actually made clear why the heater block is twisted 45 degrees in the rather confusing Prusa instructions.  I'll try to find it and link to them.

 

It is always wise to get more than one opinion......
Posted : 12/08/2019 9:56 pm
gnat
 gnat
(@gnat)
Prominent Member

For the record, the Live Z was understandably off, but it still print just fine like that! Not a procedure I recommend, however, as it was touching the housing and starting to melt it after only about 2 hours of PETG and 16 hours of PLA. 

Unfortunately I can't speak so highly for my rebuilt hot end 🙁 

MMU tips and troubleshooting...
Posted : 12/08/2019 10:02 pm
Tim
(@tim-m30)
Illustrious Member

Guy's post is in this thread:

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-general-discussion-announcements-and-releases/leaking-nozzle-heat-block/#post-156624

Copied without permission:

1. Cut zip locks that hold your heater wires or you may run out of slack

2. Heat to filament temperature and unload filament. Remove fan shroud shift parts cooling fan aside.

3. Increase temp to 285C

4. Use wrench to hold heat block in place

5. Unscrew nozzle completely.

6. Reach into empty nozzle hole and clean out old filament debris with counterclockwise twisting of q-tip.

7. Use wrench to twist heat block 45 degree onto the heat break. (viewed from bottom would be clockwise.) This should advance heat break a little further into heat block.  

8. Hold heat block in its temporary 45 degree position with wrench

9. Install nozzle. It should now impinge against end of heat break a bit sooner. Tension to two fingers tight (still at 285C)

10. Let nozzle temp cool

11. Turn off printer

12. Undo hot end cover and straighten out the entire E3d hotend assembly to bring heat block back into normal alignment. The entire assembly including the cooling fins should be rotated, not just the heat block.

13. Redo zip ties.

It is always wise to get more than one opinion......
Posted : 12/08/2019 10:03 pm
robert.t17
(@robert-t17)
Eminent Member

Please don't take this the wrong way. If you replace the E3D hot end with a Slice Engineering Mosquito, nozzle changes are a one wrench operation. Takes no time at all.

Posted : 13/08/2019 12:53 pm
Tim
(@tim-m30)
Illustrious Member
Posted by: robert.t17

Please don't take this the wrong way. If you replace the E3D hot end with a Slice Engineering Mosquito, nozzle changes are a one wrench operation. Takes no time at all.

Your post doesn't really help the OP in any noticable way.  Probably more of an insult than anything else.  So it's hard to take it any other way than how it was intended.

This post was modified 11 months ago by Tim
It is always wise to get more than one opinion......
Posted : 13/08/2019 2:04 pm
edward.c6
(@edward-c6)
Reputable Member
Posted by: gnat

Wait, so this wasn't a a problem then?

For what should be a simple procedure, there is sure a lot that can go pear shaped about a nozzle change 🙁 

I agree with Tim that the root cause is that the nozzle and heat break aren't properly mated. You'll probably need to do a full tear down of the hot end to fix this properly as the plastic that is already in there is going to keep it from letting you getting it properly snug.

Regardless of what you do, however, be very careful trying to remove the nozzle or heat break until you do take it apart to clean it up or replace the parts. The above was due to a stuck nozzle and the wrench holding the block slipping off.

Beveled prints...  Could be a "feature"

This post was modified 11 months ago 2 times by edward.c6
Posted : 13/08/2019 3:33 pm
noah.s10
(@noah-s10)
Active Member

This worked like a charm!!! Thank you everybody!!!

Posted : 16/08/2019 6:04 pm
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