This is my first attempt to make an alternative Fan-Duct for my UM2. This Part allows me to print small structures with optimal cooling the PLA at the print area. For normal sized parts i have set the fan to 50%. Please try out for optimal results on your machine. I have printed this object on filaprint-plate with plaTec from biofila, which is heat resistant up to 120°C and relatively easy printable. The warping effect is more than PLA but less than ABS. May be its better to close the building area to optimize the chamber temperature. With plaTec i have no problems with heat from the nozzle. IMPORTATNT NOTICES: (1) The distances are designt for the Olsson-Block-Nozzles. It will not work with the original UM2 Nozzle. (2) The distance from the bottom face of the Fan-Duct to the build-plate is a bit low. At the outer edges of the buildplate - where the clamps are - the Fan-Duct collides with the clamps at the first layers. Actually i use it only for smaller parts, where i'm out of the reach of the clamps.The picture with layers in Cura shows the best alignment for printing and the critical point (*) . You have to check here if the structure is closed completely. Its designed for 0.4 mm nozzle.