@jay_s_uk didnt really showed up when searching for it, the pinned macros showed up but they are a bit bulky

@dc42 thankyou, I tried the changes for R and D but it made little difference.

Eventually the temperature does stabilise so I need to have a check prior to the print start

With my limited skills I have tried to have a condition to check the heat.heaters[1].current
but I end up in a loop or it is ignored.

Could you suggest a suitable test please

Pretty sure they are just the start/stop points of lines(seams). Other than printing in vase mode they are nearly impossible to totally get rid of due to the nature of FDM printing. Things like coast, wipe, pressure advance will all help but when you have molten plastic being laid down in lines that start and stop there's not much that can be done.

Best thing you can do is properly tune your extruder, filament flow and work with pressure advance.

I know that the main concern of this type of systems, are the retractions, but from what I have been able to find out, the polymers have certain characteristics, it may be the same polymer but for different types of technologies their characteristics change, for example when they melt they flow as a liquid, but rather as a hot dough, and in theory that prevents material from dripping down the nozzle, but in case these drips occur, I plan to build a pneumatic system that stops and opens the nozzle very fast for extruder displacements .

Here you can find a system that closes and opens the nozzle.

https://wiki.utopiamaker.com/index.php/Extrusor_de_Pellets_para_Impresión_3D

It looks like you have "outer before inner walls" checked. That could maybe do it.

@hamiltonprops From re- reading your OP, you say that the temperature drops 20 degrees within a second or two. That would indicate it's not a "real" drop in temperature but rather a drop in the indicated (measured) temperature - unless your hot end has an insanely low thermal mass. So, yes I go for some sort of cross talk or electrical "noise". Are you sure you haven't got a bad crimp on the thermistor wiring somewhere?

Not mentioned fine tuning of extrusion temp in that original list. It would seem logical to go for linear/non linear extrusion correction checks as soon as your happy with extrusion temp and e-steps/mm.

@3mm I bet it even acts as a desiccant! Brilliant.