So my Prusa i3 MK2 is printing just fine and I get awesome results with PLA and nGen. But two things are missing to be a perfect printer which is living room compatible.
The y-axis in comparison to the x- and the z-axis is really loud. A few days ago I read on the Prusa website about an upgrade kit which includes new rods and bearings to eliminate this issue. So I will keep this in mind until the lead time is acceptable.
The second thing is the fan of the E3D hot end. It is a 30×30 fan which runs in full turbine mode. After reading in the forum I stumbled about a post with other users who had the same problem. One critical point was getting the same airflow as the small fan, so the hot end doesn’t clog during print. I found a nice 40x40x10 Noctua fan which fits my needs. It runs on 12 V, creating an airflow of 8.2 m³/h with an acoustical noise of 17.9 dB(A). So here we will do a fan replacement.
For the adapter, my co-worker printed a nice adapter in orange ABS (http://www.thingiverse.com/thing:1827477).
The fan replacement
The old fan was unscrewed and removed. With three M3x18 screws, I mounted the new fan adapter.
Now I attached the new fan to the adapter. Be careful with the length of your screws. If your screws are too long they will damage the other fan.
With my new fan came a short cable with a three-pin connector. I removed the spiral wrap on the cables until I could get the fan cable plus the connector cable in there. The old fan wires were cut. Then I soldered the connector cable on the old wires and isolated the two wires from another.
For the last step, I reattached the spiral wrap on all the cables. Check that the cable doesn’t touch the heated bed.
Now that the fan noise vanishes after the fan replacement the Prusa i3 MK2 is really quiet. Only on the bed leveling procedure, the y-axis makes noises. But now that the printer is so quiet I located a rattling noise which seems to come from the extruder. It only occurs some times during print and I couldn’t locate it further. I reassembled all the screws on the extruder because it sounds like a loose nut. But this doesn’t help. I fastened the screws which mount the new fan which seems to fix it. But some times it occurs again.
But aside from that, the printer is now quiet enough during the print.