Filament adhesion issue after 1 ok print?

I did an initial manual calibration of the machine with revised rails and v2 heard, on glass, got a pretty great 20mm XYZ cube.

I wanted to try autocalibration using PEI surface, now i can’t get the filament to adhere.

Things i have tried:

  • upping temps to 60/220 for first later
  • adjusting z-height with G1029 D (it ended up too close and still didn’t print)
  • calibrating multiple times
  • trying both my stock PEI and my energetic PEI plates.

Things i have observed:

  • the filament tends to always form loop (where it looks like end of filament sticks to nozzle) when it is initially extruded - for example off the front left side of the bed before a print, not sure if it is doing that on the plate.

What causes the looping, rarely if ever had that on the v1 head (using same filament as used on v1 head).

What else should i look at?

This is the ‘new version’ of the sensor height instructions, it doesn’t seem coherent:

  1. its not possible using the controls post calibration to lower nozzle to touch bed (and there is no metion of using gcode to do it).
  2. the picture shows the nozzle and sensor about same height, yet the text states make the nozzle 1mm lower than the sensor
  3. all the credit cards i own are about 0.82 mm - so what do they want 1mm or a credit card thickness… (i assume the latter as that’s what it has come set from the factory as)

the seems to no longer mention the need to change the mounting of the head (or remove it) to do this to access the sensor screw… I assume its still needed?
What should I do if the 3D Printing Module pushes into the Print Sheet? – Snapmaker

heating the nozzle to 230 and using some paper towel to get rid of this stuff improved it enough to do a skirt and then it clogged starting to do the first layer of the object, it was filament adhering to nozzle again in a really bad way - ffs i might just go back to the old print head.

If you’re having trouble setting nozzle height, I can recommend getting quantitative and using a tool setter (example non-affiliate link).

An inexpensive digital thermometer with a bead thermocouple sensor would tell you whether your hot end was reaching the temperature you think it is.

does a digital meat thermometer have a bead sensor
if not i can look at getting one of the few on amazon that explicitly mention bead

this isn’t a nozzle setting height issue (at least not using the card) - i have gone back to my v1 head and just printed fine. Though that meat thermometer only reads about 160c when the nozzle is at 200 (but i think the fan is on…)

I picked up a cheap Harbor Freight digital thermometer a few years ago for around USD 20. It came with a bead thermocouple. 5 packs of K-type bead thermocouples are on Amazon for around USD 15. Cheap thermocouples assemblies have cheap insulation on them, so take care about extended heating.

There’s room for another hole on the back of the heater block in the hot end. Or just slip it under the silicone sock. Might also need a piece of Kapton tape or other insulator if the heater block presents electrical interference.

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