Hot end not getting to temperature.
Hello,
Last weekend I swapped 0.4mm to 0.6mm for faster prints. I made sure the nozzle was snug but not overtightened. However during every print I did, there were blobs of PLA on my prints. There were two areas of leak, one from between the nozzle and the heat block and another between heat block at the metal cylinder with fins.
I therefore disassembled the extruder assembly to get to this. I preheated the hotend and then tightened everything up nice and tight
When I went to calibrate and set up for my next print, the hot end got to about 160 Celcius no further. So I diassembled the extruder once more. When the hot end is dangling down, it gets to temp but when I place it in the carrier, it doesn't.
Therefore, this means the extruder fan is cooling it down when it shouldn't.
I don't really understand how I have caused this problem. Should the extruder fan be on whilst the hot end it heating up?
Any ideas how to resolve the problem. Under settings, the fan speed is set to zero.
Thank you.
RE: Hot end not getting to temperature.
Didn't follow the E3D or even the Prusa hot end nozzle change instructions. Thus it leaked.
And yes, the extruder fan MUST be on while the heater is working.
It sounds like you may have damaged the heat break, or have the assembly so foo-bar the heater block is contacting the heatsink.
RE: Hot end not getting to temperature.
@tim-m30
Thank you for the reply. I did have a look at a few videos including the Prusa Nozzle change. I held the heat block with an adjustable wrench and undid the nozzle with a 7mm socket. I stuggled to get the original 0.4mm off as it was very tight. So when I attached the 0.6mm I made sure it was snug but not overly tight. I think I had to be slightly tighter than this and of course I didn't check for leaks after.
I think you are right about the heat block contact the heat sink as I did tighten it all the way - rookie mistake but remember I was trying to rectify a leak and therefore I tightened everything up.
I bought a range of brass Nozzles from Amazon for the V6 hot end - could the new nozzles be responsible for the leak. I will rectify the issue when I get home from work.
Thanks.
RE: Hot end not getting to temperature.
Never buy cheap nozzles from amazon or elsewhere. Just get proper e3d ones as you know they will have the correct specification of thread length etc
RE: Hot end not getting to temperature.
And - it sounds like you didn't heat the hotend to do the initial loosen and final torque. The nozzle loosens up when hot - and unless you do that step you can break the heat break. And, not torqueing the nozzle tight after replacement will cause the hot end to leak like a sieve.
Honestly, it sounds like a full disassembly and inspection is in your future. But, before you do that - please - read the instructions or you'll just do more damage. While the process seems intuitively simple, there are critical details that aren't intuitive at all: heat break neck is thin stainless steel which does not like torque, the copper-stainless interface requires a lot of force to seal properly, and the heater block is not part of the seal; to name a few.
https://e3d-online.dozuki.com/Guide/Changing+Nozzles/45
https://e3d-online.dozuki.com/Guide/V6+Assembly/6
https://wiki.e3d-online.com/E3D_Nozzles
https://help.prusa3d.com/en/article/changing-or-replacing-the-nozzle_2069
RE: Hot end not getting to temperature.
Ok issue resolved. Thank you Tim and neophyl.
So this is what I have learnt as a reference to others.
1) As Tim has said, the nozzle screwing into the heatblock and the heat break screwing into the heatblock from the opposite side and ARE NOT seals. The seal is made when the nozzle threaded end meets the heatbreak threaded end - their flat surfaces meet to create a seal.
2) The reason why my heatsink was touching the heat block is because the aftermarket nozzles that I bought have shorter threaded ends. So where I thought the seal is created by screwing into the heatblock, the two ends (nozzle and heatbreak) weren't actually meeting inside the headblock to create a seal. Therefore it was leaking in two places and also why the heatsink was touching the heatblock.
Thanks guys
RE: Hot end not getting to temperature.
[...] 2) The reason why my heatsink was touching the heat block is because the aftermarket nozzles that I bought have shorter threaded ends. So where I thought the seal is created by screwing into the heatblock, the two ends (nozzle and heatbreak) weren't actually meeting inside the headblock to create a seal. Therefore it was leaking in two places and also why the heatsink was touching the heatblock.
This really underscores @neophyl's point on cheap nozzles. I use P3-D and E3D nozzles almost exclusively. If I just want to experiment with an odd size, TriangleLab are decent cheaper clones. The really cheap ones are almost guaranteed problems.
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RE: Hot end not getting to temperature.
Glad to hear you didn't break or even bend the heat break - common outcomes when users don't use the instructions.
As for brands, I use E3D. If I ever decide to try carbide, there is a solid carbide version out there I'd have to look up - and is more expensive than a solid gold version - but I'll go that direction rather than hardened steel.
RE: Hot end not getting to temperature.
@tim-m30
Thanks for the help this morning. You put my mind at rest when I was at work.