Heat Creep on V2 nozzles

Cetus Cetus 1st Gen MK1-MK3
#1

Hi,
I’ve been using a MK2 Cetus with the V2 extruder. Up until recently I’ve been using the V1 nozzles. I decided to try out the new version. It looks like a better design all around, except there isn’t a PTFE tube inside. I’m printing PLA and so far have clogged almost all of my V2 nozzles and barrels. I have a feeling that heat creep is my problem.

I’ve haven’t changed any temperature settings from when I was using the V1 nozzles, so the temperatures are the same. I’ve tried different spools of PLA, slower and faster print speeds, different nozzles/barrels.

What would be my best option to mitigate this issue? I have PETG and ABS material, but I think my problem would just be worse if I tried printing those. I’m tempted to try boring out one of the barrels through the heat sink section to fit a PTFE tube inside. Any thoughts are appreciated.

#2

I’ve been looking more at the option of boring the barrel out some and putting a PTFE tube inside. But as I’ve looked at it more, I think there’s a little piece of PTFE tube already in there. It’s hard to really tell, but it looks like there’s something in there. Can someone confirm that there’s PTFE already in the new barrels? If there is some in there, it looks really thin. I don’t know if it would have the mass to help insulate the filament from the heater. So, I’d still be inclined to bore the barrel and put a 3mm diameter PTFE tube in it.

I’ve also noticed that with the new barrels/nozzles, I can’t withdraw the filament cleanly. Every time I withdraw the material, it always catches on some kind of lip that’s at the top of the barrel as it comes out. I’ve had to push it out the nozzle or cook it out with heat. I wonder if these are related in any way.

#3

Hi BusyMoss,
there is definitely something inside the barrel. The problem is that we have no option to control PID as all the critical parameters are pre-set. Changing from V1 to V2 obviously have an impact on these settings hence the problem with heat creeping up. Every printer is slightly different and we really should have this option to set our own PID but unfortunately Tiertime never consider this.

#4

Thanks for the note jaskry. I’ve pondered this some and am wondering about the TinyFab kit. I’ve seen that one can calibrate the PID for the heat bed. But can you calibrate the PID for the nozzle as well using the TinyFab kit?

I tried it out. The heat sink section of the nozzle is drilled out to the same depth as the V1 nozzle. And now has a 3mm PTFE tube installed in it. I’ve been able to successfully print PLA several times and with some prints that have lasted over 10 hours. Previously, I couldn’t print for longer than 30 minutes before it failed. Since making this change I’ve had two failed prints because of the clicking extruder. I think in this case it’s material related, but I’m not certain yet what’s the cause of those failures. But so far, I’m more satisfied with the results. I still wish the printer was more reliable, but I know it can’t be 100% reliable.

I have yet to try printing PETG or ABS using this modified V2 nozzle.