Ultimaker printhead with top-mounted fan. I was inspired by Coyote69's lightweight printhead. I used that design for a few days until it warped during a long print. I tried several iterations and this one seems to work well. I've been using it for several weeks now. The weight reduction between the stock Ultimaker parts and the printed parts and fasteners is about 20 grams - so it's not great, but is a reasonable reduction. Most of the weight reduction is due to short screws instead of the long thumbscrews. The top-mounted fan is not intended to cool the nozzle (active cooling), but to replace the side-mounted fan. To keep the heat from distorting the printed parts, I tried to move those parts away from the hot bits and changed the how the loads are distributed around the clamped nozzle. I am still trying to improve airflow around the nozzle with various air duct designs. Since the airflow goes around the heater block, I strongly recommend adding some insulating material around it. I also slotted the rear two holes in my stock aluminum plate to improve airflow. Although my intention was to mount the standard 50 mm fan to the top of the print head, you could still mount your fan in the standard location. It would just require slightly longer screws than called out in the drawings. Currently the files are for a single extruder. Since I plan to add a second extruder eventually, I have designed it so that option is still available - but I have not created those files yet. If others are interested, I can develop them. Because routing the wires through the printhead would reduce the airflow, they are routed along the exterior. Some of the STL's have "ears" to help hold them to the build platform when printing ABS or nylon without a heated bed. Please remember, this is a work-in-progress! 8/12/13 UPDATE: I had some issue with my Bowden tube slipping out of the retaining clip, so I reduced the depth of the chamfer on UPPER BEARING MOUNT (PH-V1-003). I have removed the old file and uploaded the new file. Now the Bowden tube is much more secure. As a short-term fix (if you don't want to go through all the effort of replacing the entire part), just flip the locking clip upside-down so that it is effectively "thicker" and that should keep the Bowden tube from moving. That seems to work because the locking clip has a tab on the top side. I have also found that merely turning the heater block at a 45 degree angle allows much more airflow with the existing air duct design. So in this setup, the heater and thermocouple wires are just below the front-right clamping screw. 8/15/13 UPDATE: I've just added two more files (PH-V1-050 and UPH-01-010). It is a Bowden clamp and nut. This would be used if you already printed out the earlier UPPER BEARING MOUNT (PH-V1-003) prior to the adjustment of the chamfer depth which can cause the Bowden tube to slip, or if you do not have the standard retainer clip that comes with the Ultimaker. This design is essentially the same setup used for thing 133526 (http://www.thingiverse.com/thing:133526). It should be used with some masking tape and PTFE tape. See thing 133526 for more details.Download the two PDF files for details. Important: (1) Make certain the Bowden tube is fully seated into the Teflon insulator. (2) Properly orient the TRANSITION DUCT ("X" to the front).