Hi, Yesterday I upgraded from a J-Head with 0.5 mm nozzle to a E3D v6 0.4mm nozzle (all 3mm) direct. I only upgraded as my resistor in the J-Head broke, and even though I fixed it with a new cartridge, I was excited about the change to an E3D and improve with a 0.4mm nozzle. I am using PLA, updated simplify3D with the new nozzle diameter, and the rest of the parameters remaining the same. I am completely unable to achieve consistent prints with the E3D... I am constantly getting random under extrusion. I use the same gregs extruder, same motor, same everything. With the J-Head everything works flawlessly, but with the E3D there is no way I get a nice print. Any ideas ??? So far the only thing I've done is to increase a little bit the current in the driver, but no changes at all. I am seriously considering removing the E3D and reinstalling the J-Head at this point Photo: Left J-Head print, right E3D.... same plastic, same temperature.