To make a more compact, accurate and robust print head , we redesign it, aiming at a totally leak-proof construction with high precision and stability of the flow up to very low feed rates. We added easily replaceable self-lubricating sealing, and reduced the clearance. Several test samples of the auger screw are 3d-printed now from wear-resistant stainless steel to optimize their shape. New design stays not only as robust as the previous one, but also is completely compatible with the previous version of the print head. Thus, the owners of our printers and KITs will be able to upgrade them with new components at low cost. Upgrades and new print heads will be available soon.