One of the most effective addons for my Mini Kossel:To achieve good results when printing PLA, especially with lots of overhangs or bridges, a dedicated layer fan is essential.I use the "high-rpm", server-grade version of Sunon fans (Type: HA30101V2-0000-A99). The important part in the ID is "V2". This indicates the 9k rp/m version. The ones usually sold are marked "V3", they run with 5.6k rp/m and are meant for home entertainment applications. They run quiter but with less airflow. I uploadet two designs: -The fist one (...-type2.stl) for the standard JHead. It has two 50° air nozzles and it is my preferred design at the moment. I've added two mounting brackets with M3 holes for future use. Maybe for some kind of Z-sensor.-The other one (...-long.stl) is for longer hot-ends (like the marlin or some of the infamous JHEAD Mk IV clones). It has two 35° air nozzles.And, well - it works like a charm. :-)