How to clean heatbreak flooded with melted PLA  

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daniel.mihailescu
(@daniel-mihailescu)
Eminent Member

Hi,

I changed the brass nozzle with a stainless steel one and it looks that the new nozzle did not sealed well on the heatbreak and melted PLA flooded all over the hotend during a print. In order to clean, I have removed the heater, the thermistor and then the entire heat block from thje heatbreak. I used a torch, sand paper and others to clean the plastic melted on all parts but now I  have reached a dead end. The heat break end is still covered with melted plastic, see the picture.

         

The heatbreak could be unscrewed by hand up to a point but at the point in the picture is stucked. I do not know if I should force unscrewing  in order to  take it out completely and clean it up.  

What is the best approach to have it cleaned with minimum disassembly required. I heard that there is a thermal compound somewhere but i do not where exactly should be put. I already tried to clean with metal brush but results are not good. 

Any help is highly appreciated.

 

Kind regards,

Daniel 

Posted : 02/07/2020 6:45 pm
daniel.mihailescu
(@daniel-mihailescu)
Eminent Member

Hi,

Actually I pushed a little more and the heatbreak unscrewed completely. Now I can see  with a mirror the PTFE tube inside the extruder.

Best regards,

Daniel  

Posted : 02/07/2020 7:00 pm
Karl Herbert
(@karl-herbert)
Famed Member
Posted by: @daniel-mihailescu

Hi,

I changed the brass nozzle with a stainless steel one and it looks that the new nozzle did not sealed well on the heatbreak and melted PLA flooded all over the hotend during a print. In order to clean, I have removed the heater, the thermistor and then the entire heat block from thje heatbreak. I used a torch, sand paper and others to clean the plastic melted on all parts but now I  have reached a dead end. The heat break end is still covered with melted plastic, see the picture.

        

The heatbreak could be unscrewed by hand up to a point but at the point in the picture is stucked. I do not know if I should force unscrewing  in order to  take it out completely and clean it up.  

What is the best approach to have it cleaned with minimum disassembly required. I heard that there is a thermal compound somewhere but i do not where exactly should be put. I already tried to clean with metal brush but results are not good. 

Any help is highly appreciated.

 

Kind regards,

Daniel 

With a hot air gun and a brass brush you can easily remove the plastic. I would not use a stainless steel nozzle for PLA because this material has a much poorer thermal conductivity and you have to set the printing temperatures higher. Stainless steel is often used as a heat stopper (heatbreak), so I would increase the nozzle temperature by at least 20 degrees C. or more. Do you print parts for the food industry?

 

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 : 02/07/2020 7:17 pm
daniel.mihailescu
(@daniel-mihailescu)
Eminent Member

Hi Karl,

Thank you for the reply, heat gun approach did not occurred to me :). I have one but I do not know what temperature is outputting. Another drawback is that is big and hard to handle in that space. However the heat break is now removed and I cleaned it. Now I have to put the thermal compound and mount everything back. This without removing the whole  heat assembly. 

I changed the nozzle with a stainless steel one because I heard that is a more wearing resistant one. The difference to my knowledge is the heat propagation speed, but once it reached the temperature it should be the same,  I will measure it with the thermal camera as soon as I have it mounted back. However it has a bigger heat inertia so fluctuation on ambient temperatures will not be reflected that fast on the nozzle.

I made some digs and now I know also where to put the thermal compound. I am also considering to replace the heat break with a new one the E3D standard since more people recommended to decrease the nozzle clogging on some filaments.

Any suggestions?

Best regards,

Daniel 

Posted : 02/07/2020 7:37 pm
Karl Herbert
(@karl-herbert)
Famed Member

@daniel-mihailescu

With a brass nozzle you can print many kilometers of PLA. The temperature is measured and controlled in the vicinity of the heating block, whereby the stainless steel nozzle does not reach this temperature. I can only repeat myself - raise the nozzle temp - it's worth a try!

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 : 02/07/2020 8:37 pm
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