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PTFE stuck in cold end  

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JoanTabb
(@joantabb)
Veteran Member Moderator
PTFE stuck in cold end

Hi folks,
My mmu cold end PTFE tube needed changing...

I have previously had the cold end apart and sorted the ptfe with no problem...

I used heatsink paste on the threads to improve heat transfer and stop the heat break becoming stuck in the cold end heatsink, so I wasn't expecting problems.

I already have replacement ptfe on hand.

dissassembled the cold end housing,released the heatsink, and unscrewed it from the heat break, all went wonderful...

gently pressed the ptfe tube into the heat sink,it didn't budge a micron...

tried harder and much harder, no chance... ended up deforming the ptfe horribly....

tookthe old mk2 assembly apart, no problems
measured the length of heat sink, identical, pressed the ptfe, it slid through no problems... so I have used this heatsink and reassembled,after checking that the ends are chamfered, cut to length and flared appropriately... printer is now working again

has anyone else had a similar problem? if so, how did you remove the remains of the ptfe... the hole is clear, btu the tube seems irremoveable

regatds 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 : 04/10/2017 2:19 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: PTFE stuck in cold end

Yeah, it's happened to me as well.

Seems that either some "special" PTFE tubing is oversized or the hole in the heatsink is under on some parts.

Managed to push out the PTFE with the blunt end of a 3.5mm drill bit. But swapping out the heat sink works; they are all the same.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 04/10/2017 9:12 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Topic starter answered:
Re: PTFE stuck in cold end

Thanks Peter.
maybe you were more insistant than me....

I couldn't get it to move at all 🙁

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 : 04/10/2017 12:09 pm
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