HOTEND leaking after nozzle replacement  

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mastersrybnik
(@mastersrybnik)
Active Member

Hi,

 

I am an absolute novice to 3d printing and desperate for help. I have prusa mk3s and was using it just fine untill 3 days ago when I made a mistake of cleaning the nozzle improperly after some suboptimal PET-G to PLA filament change where I didnt run PLA on higher temp to clear it out. I think I must have touched the nozzle when hot and maybe screw it up cause printing went bad and there was a lot of stringing despite doing cold pull where there was litreally zero residue.

I decided to order and replace the nozzle. Followed the prusa video/instruction on how to change it to the best of my ability make sure I was doing it set by step even watched like 5 different youtbers doing it. Thats now done. I recalibrated xyz and 1 layer.

So the problem now is that i get a leak (I think) of filament from the top of the hotend which goes down by one or two sides of it and ends up on the nozzle, gathers there and finally ends up on the print as a blob lets say. Now as for the print itself it is damn perfect quality but I have to stand there and clean off the spillage every 25 minutes or it messes up the print. So obviously I stopped printing.

I just dont know what to do. My knowledge is very limited.  This is my first printer and I have been printing the facemasks for hospitals non stop for 2 weeks and now I cant. Half of my family are doctors so it really is unfortunate.

Appreciate the help.

Posted : 08/04/2020 10:21 am
neil.t
(@neil-t)
Eminent Member

mastersrybnik, Many of us have been in a similar situation: this is my procedure that I follow - please don't burn yourself following it:

https://neilt.org/notblog/Prusa_MK3SMMU2_E3d_V6_Hot-end_Nozzle_Changing_Procedure.html

E3d has good information for fitting a nozzle as a step in assembling a V6 hotend: https://e3d-online.dozuki.com/Guide/V6+Assembly/6

Cheers

Digbat

TANSTAAFL...
Posted : 08/04/2020 12:50 pm
mastersrybnik
(@mastersrybnik)
Active Member

@neil-t

Filament Leak!

  • Stop printing!!
  • Do not allow the leak to build up burnt plastic residue!
  • Check that you fitted the nozzle correctly. There must be a (small) gap between the top of the Nozzle and the bottom of the Block.
  • If the nozzle is flush against the bottom of the block, then you could disassemble and rebuild the hot-end to stop the leak.

I really am not that bright so if you could go into more detail I would apprieciate man.

From what I am reading i fully suspect I did something wrong when chaning the nozzle and comments everywhere are all talking about heatbreak bend possibility which would maybe be consise? How do I check if thats the case.

Posted : 08/04/2020 1:06 pm
Neophyl
(@neophyl)
Noble Member

Forgive me if you know any of this already but ....

Thats an outline of how the extruder assembly is internally.  The heater block as well as holding the heater and the thermistor to measure the temperature acts as a big nut holding the heatbreak and nozzle together.

The most common mistake when people change their nozzles is to have a slight gap between the nozzle and heatbreak as you cant see it as its inside.  That's one of the main reasons people advise having a gap between the nozzle and heatblock, as if its tight against that how can you tell if its touching and tight against the heatbreak ? and you cant screw it in further to meet the heat break.

When theres a slight gap between nozzle and heat break you get uneven pressure which results in uneven printing.  You also get plastic working its way up the threads and down.  So eventually you see plastic appear at the top of the heat block.  Of course on a Mk3 its difficult to see that so the first sign is usually when bits of blackened plastic fall onto your prints from the stuff thats been cooking up there.

You want it finger tight between the heat break and nozzle initially and then the extruder needs to be brought up to around 285C for a final tightening at full temp.

 

If you have bent your heatbreak the heat block would not be level/square (check from all angles).

Posted : 08/04/2020 1:37 pm
Karl Herbert
(@karl-herbert)
Famed Member
Posted by: @mastersrybnik

Hi,

 

I am an absolute novice to 3d printing and desperate for help. I have prusa mk3s and was using it just fine untill 3 days ago when I made a mistake of cleaning the nozzle improperly after some suboptimal PET-G to PLA filament change where I didnt run PLA on higher temp to clear it out. I think I must have touched the nozzle when hot and maybe screw it up cause printing went bad and there was a lot of stringing despite doing cold pull where there was litreally zero residue.

I decided to order and replace the nozzle. Followed the prusa video/instruction on how to change it to the best of my ability make sure I was doing it set by step even watched like 5 different youtbers doing it. Thats now done. I recalibrated xyz and 1 layer.

So the problem now is that i get a leak (I think) of filament from the top of the hotend which goes down by one or two sides of it and ends up on the nozzle, gathers there and finally ends up on the print as a blob lets say. Now as for the print itself it is damn perfect quality but I have to stand there and clean off the spillage every 25 minutes or it messes up the print. So obviously I stopped printing.

I just dont know what to do. My knowledge is very limited.  This is my first printer and I have been printing the facemasks for hospitals non stop for 2 weeks and now I cant. Half of my family are doctors so it really is unfortunate.

Appreciate the help.

The nozzle must seal 100% properly in this area:

Therefore you should disassemble the hotend and clean all components, after that screw the nozzle into the warm (250degree) block with a torque of approx. 3NM.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/04/2020 1:47 pm
neil.t
(@neil-t)
Eminent Member

mastersrybnik,

Try this very helpful explanation: - I wish I had found this before my first blob of doom lol.

Theory up to 2:30 after that comes very clear guide using a excellent model. Could be worth 5:21 of your time.

Cheers

Digbat

 

TANSTAAFL...
Posted : 08/04/2020 1:57 pm
mastersrybnik
(@mastersrybnik)
Active Member

@karl-herbert

Unfortunately I lack the knowldge how to take apart the hotend and even if i do I dont have the hotair to clean it. With epidemic its hard to even borrow anything really.

Kinda thinking of just going to 285C and trying to tighten the nozzle but I am afraid I will only make it worse.

If what you say is true about the heatbreak - it cannot be it since i printed 3 elements and they look almost perfect comapring to old ones expect the dripping points.

Posted : 08/04/2020 2:25 pm
mastersrybnik
(@mastersrybnik)
Active Member

@neil-t

Not gonna lie man in those 5 minutes i gained more understanding of how this works then I have in trying to read smart posts for the last 2 days.

The problem is everyone here have tools and know how and I just lack it and I am really afraid to take apart the hotend to be honest. Also dont know how much that would do since I dont know how will i clean it even if I manage to do that.

Whould you by any chance have some good video of this sort for mk3s hotend cleaning?

Posted : 08/04/2020 2:29 pm
neil.t
(@neil-t)
Eminent Member

mastersrybnik, I should have said upfront: well done for your work printing PPE - many of us are doing that and I'm starting to get feedback from those I know that health professionals appreciate all our efforts and are using 3d printed PPE.

There are a few other youtube videos about assembling the E3dV6 so you could find one that works for you. I agree that the thought of taking the hot end apart and putting back together could be a little scary but after doing it I expect that you will gain confidence and gain new skills. I suggest that before working on a hotend you buy in spares - I always have a spare heater and spare thermistor because these are quite fragile and we (I have) may break them (in fact I keep an entire hotend spare). Amazon in UK stock genuine E3d bits so I guess that is the same in most countries, E3d are usually quite quick shipping, and of course Prusa stock hotends and parts. When I was in your situation I: bought in spares, disassembled the hotend, reassembled, gained experience by doing it and got printing again. In my case I broke the heater wires doing all that but - no problem, I had a spare. I learned a lot from the experience. I do at times change nozzles more than once daily but I generally don't have to deal with leaks anymore because I learned from doing. I that hope it goes well for you.

Cheers

Digbat

TANSTAAFL...
Posted : 08/04/2020 5:34 pm
mastersrybnik
(@mastersrybnik)
Active Member

hi guys i just finished working on this and im here to pay my gratitude.

I was not able to do the complete cleanup of the hotend as I do not have tools or spares in case i do break somthing so I am not willing to risk it. However since you took time to teach me basics I never knew I was able to understand my mistake and fix it. After 2 days of struggle to find any help on Polish forums where ppl mainly just throw oneliners and never care to explain this was something I was not really expecting. As it is with politness today - it mostly comes when I dont expect it.

In the end I stole a sewing needle from my wifes kit took nozzle/hotend to 230c and started cleaning it. I was long and painfull and its still not perfect but it is working just fine. Then I set nozzle to 285 and tightend it up just as far as I could see it makeing a difference. Z calibration and first layer calibration went smooth. I monitored first print non stop and it was just a normal print with me being paranoid. A second PPE is already printing and there is no leakage for now. Nozzle looks clean. There is some extremely minor strings on the print but that is nothing, tiny inaccuracies.

I liked both of your posts please let me know if I can do anything to boost your rating on the site, sub to channels or do whatever I can to repay this kindness.

Just want to say this was so important to me since I have 3 doctors in my family and none of them are provided with PPEs in the hospital they work at. I've been printing non stop for two weeks and everything I print is gone the same day after I assemble it with screens and rubber bands. Now my sisters friends are also contacting me asking if they can get one and it was tought to say I cant print. Appologies for the longish post but I just wanted you to understand this is not a small thing for me and I will remember this kindness always.

Cheers, mss

Posted : 08/04/2020 10:30 pm
burtronix liked
Karl Herbert
(@karl-herbert)
Famed Member

@mastersrybnik

If it helps you, I could send you some spare parts for the hotend (heatbreak, heater block, thermistor, heater cartridge, PTFE tubes, nozzle cleaning needles). If you are interested, send a message.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/04/2020 10:53 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: @mastersrybnik

[...] Just want to say this was so important to me since I have 3 doctors in my family and none of them are provided with PPEs in the hospital they work at. I've been printing non stop for two weeks and everything I print is gone the same day after I assemble it with screens and rubber bands. Now my sisters friends are also contacting me asking if they can get one and it was tought to say I cant print. Appologies for the longish post but I just wanted you to understand this is not a small thing for me and I will remember this kindness always.

My son is a doc, and this is personal for me as well. I've prepared a page with my notes on printing PPE on the Mk3 that you may find interesting. I've focused on using a 0.6mm nozzle, but many of the settings apply to the 0.4mm nozzle as well. If you are having a challenge finding suitable rubber bands or elastic locally, I've posted a material saver print that works with the Prusa-style shield frames. I've printed it in PETG and it works well, allowing me to print everything but the clear face shield material. We had an elastic shortage here briefly, and I wanted a work-around. I think the plastic parts are easier to sanitize as well.

Welcome to the fight, sir!

 

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 08/04/2020 11:05 pm
burtronix liked
Neophyl
(@neophyl)
Noble Member

Weirdly enough I've been printing buttons recently.  My mother and her sewing group friends have been making cloth face masks with elastic for friends at nursing homes and other secondary care facilities.  Well extended use rubs the skin behind the ears raw  so they started making headbands with buttons on that the elastic could fit around  instead of the ears.  But then they ran out of buttons, so I designed a military style one with a central bar that prints quicker than the usual style with holes and have printed out a few hundred for them to use.  Every little helps right 🙂

This post was modified 4 months ago by Neophyl
Posted : 08/04/2020 11:17 pm
mastersrybnik
(@mastersrybnik)
Active Member

@karl-herbert

Thanks man but money is not an issue in my case I am good. I will order parts in time and take time to learn and get actually good at this. Time is what is hard to come by even thou I spend 99% of time in home as we all do.

Really appreciate the offer but I will could not take it. You are appreciated.

Posted : 08/04/2020 11:43 pm
mastersrybnik
(@mastersrybnik)
Active Member

@bobstro

Thanks for sharing man. I am not printing the us/prusa version actually. I found a project much more suitable but you may find it lacking in standards. The one I am doing does not have the forehead protection and is extremely simple and material saving. It allows for single person production with no complicated materials and takes about 90seconds to assemble one PPE. All you need is 0.2mm laminate foil (or whatever you call it in english), rubber band with holes cut to 27cm, and 3d print. With one prusa MK3S and 0.4mm nozzle I am turning out 10 a day if eveything is going smooth and I cant even print multiples since I have no idea why it comes out all melted into one (I have a 6 and 10 piece file but it just doesnt work since i cannot separate them without breaking half).

With the project you provided I would never go above 4 prints maybe 6 a day (not even talking about material usage) most likely and while they are better quality my sister said that it is not worth it. Main problem is direct airflow to the face in her opinion and this is what I went for. She is ER (in Poland SOR) doctor and none of them had masks before I started doing this. So they could all have a mask in 2-3 weeks or a better mask for maybe 20% in same timeframe. I made the obvious choice. My uncle and his doughter are working internal oragans and there also nobody has PPEs. Well they do now some of them but im in progress on that.

If you are interested to just see how the print looks here is a yt link with full credits to this person in it who created it:

https://www.youtube.com/watch?time_continue=3&v=CCAeBn4XG9M&feature=emb_logo

Language is Polish but you can see what it is all about and if you need a traslation hit me up.

 

Additional bonus for this project also more ppl want to help with no printers and it is easy to engage them. I have 3 friends now who are making 7 day kits with rubbers and screens shown in the clip only (no print). And we give them away with to people who already received my PPEs. This way they can just throw away the original rubber and screen sanitize the print and just pop in a new one. It takes litreally 10 second flat. I had so many ppl asking how they can help - this way they can.

Anyway man thanks a lot for advice. Maybe we can meet up after world goes back to normal.

 

Posted : 09/04/2020 12:01 am
mastersrybnik
(@mastersrybnik)
Active Member

@neophyl

Are you joking man? PPEs, buttons or anything you do is appreciated. I think it is good actually we do diff things since doctors needs diff things.

I am actually planning on printing the support for tying masks behind the head as I know it is a struggle to work 7 days a week with mask tied to ears. I have seen my sis ears litreally being full on red. I when I finish getting them PPEs its definetly coming. I dont have a project yet thou so must find one.

Posted : 09/04/2020 12:06 am
Neophyl
(@neophyl)
Noble Member

@mastersrybnik

No I know that anything we do all helps, I just find it really bizarre that I have this high tech wonder and it’s being used to make buttons, one of the oldest, simplest things we use. 

Posted : 09/04/2020 6:15 am
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