Copperhead Heatbreak for Ender 3, Under extrusion issues

[Phill1337]

Hello everyone,I recently got a copperhead heatbreak from slice engineering for my Ender3 and have massive under extrusion issues with a grinding extruder wheel since. Switching back to the standard heatbreak solves the issue so it is definitely related to the copperhead. It seems to me to be some kind of heat creep issue because when i pull out the filament immediately during the print it seperates above the heatbreak but lowering the temperature to as low as 175 °C does not solve or even mitigate the issue (with PLA, PETG has the same issue tho). I suspect the junction from the teflon tube to the heatbreak to be the culprit because i have some kind of edge that catches the filament there and i can only get it in by sharpening the end. The filament has a higher resistance to sliding after that point but not so much as to cause the under extrusion by itself.I tired changing the bowden tube and tapering the end with a pencil sharpener to facilitate a more smooth junction (consecutively). No dice.Thermistor and heating cartridge are new.The extruder has a extra heat sink to prevent overheating of the extruder gear.The bed is leveled via ABL before every print and also manually.The copperhead is installed with thermal paste into the cold end.The only thing i can think of is more airflow over the coldend but the copperhead seems to work for other people with the stock ender3 so that should not really be necessary.Thank you for your help.Regards,Phillip

[AutoWiz]

tapering the outside or the inside of the PTFE tube is asking for problems. And let me explain why real quick. While you are thinking this will create slack and allow the filament to move more freely what you are actually doing is allowing the filament to come out of alignment with the precise hole it is supposed to line up with at the very end of that ptfe tube. Personally I like to use Capricorn tubing as it has a smaller id and will even more precisely locate that filament as it transitions from the ptfe to the heatbreak.

One big question I have about your conversion is did you calibrate? That is did you first set the temp sensor calibration in your firmware to what the slice engineering thermistor is? And then second did you PID autotune that heater? Because Slice engineering likes to use 50 watt heater cartridges that are a bit different than the 40 watt we see everywhere else or the high precision 30 watt cartridges that E3D uses. If you have not PID autotuned your heater then it can swing over and under target and create all manner of problems and if you did not set the right sensor calibration you are not running at your commanded temp.

[Phill1337]

tapering the outside or the inside of the PTFE tube is asking for problems. -Yeah, that was more an act of desperation.Personally I like to use Capricorn tubing as it has a smaller id and will even more precisely locate that filament as it transitions from the ptfe to the heatbreak. -I did use Capricorn tubing as well.One big question I have about your conversion is did you calibrate? That is did you first set the temp sensor calibration in your firmware to what the slice engineering thermistor is? -I only replaced the heat break. the rest is still ender 3 stock and the problem occured before the thermistor change. However i was unaware that there is a specific sensor calibration. How do i figure out the values for that and where do i find them in the firmware. And then second did you PID autotune that heater? -YesBecause Slice engineering likes to use 50 watt heater cartridges that are a bit different than the 40 watt we see everywhere else or the high precision 30 watt cartridges that E3D uses. If you have not PID autotuned your heater then it can swing over and under target and create all manner of problems and if you did not set the right sensor calibration you are not running at your commanded temp.

I have changed so many things over the last few weeks that maybe i created problems while solving them. I will go ahead an re-tune the PID. Sorry for the missing formatting. The forum somehow does not accept my line breaks when i post. Very annoying In short: i was unaware that the thermistor needs calibration itself. How do i do that?

[Phill1337]

OK the solution was as simple as it was dumb. All metal hotends apperantly need very small retractions (ca. 3mm instead of my ususal 6). I actually thought of retraction before but i did not think to lower it THAT much. Thanks for the tip with the different thermistor types anyways. I will correct that as well