I use the tube. And a short pice from the bowden to guide the filament. My Ultimaker is shaking too. I'm thinking about a other system because I'm not satisfied!

(Do not hesitate to share photos & videos)

Nice! Do you use the tube? Or do you have some bowden cut to guide the filament? What speed do you reach? Actually, my printer was really shaking, resulting in ringing parts after this mod

I have done this project. Works very well. Only by using high speed the Ultimaker is rumbling a bit. The extrusion power is fascinating!

<p>Hey Fellas! Many others as well as I thought about this - I came up with the same approach. Respect for your prototype and model! I thought the weight might have an impact. I work on a more guided model and can keep you updated. Would love to get more experiences and feedback on your tests and tries...as soon as I have my prototype working (waiting for some parts to arrive) then I am happy to share plans and results! Roland MJ :)</p>

The added weight on top of the moving parts will cause an issue (it becomes harder to start and stop smoothly) , you would need to print much slower to get the same quality prints. I have been running my new ultimaker 2, 24 hours a day for 2 weeks and have not had a single issue , I noticed that the extruder would click once in a while so I turned the extruder speed down to 90 percent. Fine tuning of the extruder speed depends on the settings that you are using. A well tuned machine will not overfeed filament.

Hmm didn't get an email that there was a comment. Yes like that image. My issue is the feeder crushes the filament sometimes and it then scratches on the sides in the bend causing friction reducing extrusion. It gets worse with retraction :( causes slipping. I have been looking for a tube but since I moved to Norway it is difficult to get anything here for testing. First test I am looking for a slightly larger ID by maybe 0.2mm max maybe 3.25mm not sure what I can find.

Actually, guys from Ultimaker could do the test very easily, they would just need two UM2: http://img4.hostingpics.net/pics/397925incredibleexperience.jpg :-)

Just to be clear, you mean doing that: http://img4.hostingpics.net/pics/144629extruderontop.jpg (of course, you'd have to design mechanical fixations)

Anyway, even if the setup is bulky, why don't you give a try to your idea?

So you think that the tube is the main problem. I'm not sure it is. Actually, I think the problem is the length between the extruder output and the feeder input, this makes the filament act as a big spring that can be compressed or not, this is why we need so "much" retraction to get it working and we have underextrusion problems. I'm absolutely impartial, and when comparing Replicator2 and Ultimaker2, I think that having the extruder directly mounted on the feeder makes the filament flow better. However, if we really want to do the same on UM2, we'd need to do biggest changes...

I've been trying to find a replacement for the tube. Looking for a tight wrapped metal coil (similar to a pipe bender) the dissimilar materials and smoothness and coil would reduce contact friction or that is my thoughts. Seems there is no big fix yet

Another idea hat takes up space would be to have it mounted well above the machine using a standard tube. This would eliminate most of the bending and would be a near straight line down. But then would be bulky

The thing is that there is a whole column moving, and this is not really good It works, but the best would be a total re-think of the head that minimizes its height

Damn. I was hoping for a no :).

You are right, there is indeed vibrations on the top. There is less underextrusion problem, but this is indeed not perfect because of the geometry of the extrusion that is really extended.

I was looking at this option earlier when I had some issues with under extrusion for a few weeks. I thought the stepper weight may cause sagging/twisting on the x/y support rods when moving at higher speeds. Have you noticed any issues with sagging or twisting at the higher movement speeds?