Daid

First of all, the Cura first run wizard could guide you a bit better. With some photos, and better guidance. Sorry about that. It assumes you do a cold extrusion, but I haven't found a difference between cold and hot extrusion. But some people say there is. (putting 100mm of filament trough the hotend would create quite a mess, and wouldn't work at the speed it is using for the calibration) On how to do it, I did it like this: http://daid.eu/~daid/IMG_20120302 ... small.jpeg http://daid.eu/~daid/IMG_20120302 ... small.jpeg If you enter the extruded length into Cura, then it will update the "steps per E" for you. No need to use formulas. (which would be silly, why let the user calculate something if you have a big calculating machine in front of you)

I think Ultimaker ships sample robots these days, so you could ask them. But I don't think they will do custom samples, unless you are planning to order big.

I have the printed stock on my dual extrusion machine, it works quite good, but it could use more cooling on the other end of the nozzle (You can visually see the difference on how the object was orientated on the platform) So it could be better, but it's not so bad that I'm having problems. Else I would have designed something already

If you have digital calipers, try measuring the white filament, maybe it has varying thickness?

What you see is called "warping", there are different ways to counter it, but it happens because the plastic is shrinking. (and the first layer shrinks while the next one is put on top) One option would be a heated bed. Another is changing your model so it has less tension in the first layers. Another trick is to add small round pads which stick to the bed, like this: http://www.thingiverse.com/image:109366 and cut them off later.

If you have a bowden tube that is compattible with the current hotend, then it will also work with the next hotend, so no worries there.

To use the heater you need to configure a sensor, else Marlin cannot control the heat.

You painted it! good boy I think the people with problems are a minority, they should not be ignored, but there are vastly more machines sold then there are people with major problems.

At the configuration file, about the spot where you configure the extruders and heated bed. Or use: http://daid.eu/~daid/marlin_build/ so you don't need to mess with config files yourself.

If it's missing steps then you usually can see that it doesn't turn smooth, you can also check by simply trying to turn the extruder gear by hand while the motor is powered, this should be quite hard (but not impossible)

It could also be missing steps. And don't assume I am right, I'm also just guessing.

Bernards power supply is an industrial one. Farnell seems to sell them. At the category "Power & Line Protection -> Power Supplies Switch Mode - Enclosed". But a 300W supply 24V sets you back well over 600 euro...

You'll have to compile the firmware with a heated bed enabled or 2nd extruder enabled. But then they work.

You'll get the best results if you leave it at the real nozzle size, but some people like to experiment with it. If you lower it, then Cura will try to put down thinner lines, which is hard. If you increase it cura will put down thicker lines, which will put more pressure on your nozzle.

Have you hooked up the GND of the 2nd supply to the GND of the Ultimaker?

I would keep the start code intact, and then delete everything up to layer 100

No problem in that, it's the way to fix this bug problem. It's a bit of a "packaging software for linux is hard" problem.

I suggest using Cura, it allows you to preview the GCode and then you can see if your printer will output the gate or not.

Firmware is my speciality Cura is actually the odd project for me. I've already added M0/M1 support to the firmware a while back. Pause on the Ulticontroller is just an extension of that.

Not yet. It's on my to-do list (like a lot of things)

Actually, ABS is a bit more springy, that's why most of these "clamp to fit" parts are quite hard. Have you tried the screwless cube gears? those work for me with PLA.

Actually, the jam happens because the bowden tube moves up. The white+blue clip does not always seem to hold the tube in place. A printable solution is: http://www.thingiverse.com/thing:11864 See:

Do you see any exceptions in the console window? You can also try setting the baudrate from AUTO to 250000 in the preferences. The AUTO baudrate is new in the latest version and is causing some problems on some systems (but not on all, making it harder to track down)

Most likely you are right with the burned plastic. You could try taking the head apart and add some more plumbing tape. But be careful with taking it apart, as it is easy to break, and it should be done while hot (making it harder)

I've never seen it happen that a bowden tube pulls on the head. (and my machine has 2 tubes) I have seen it happen that the head moved because of "bumps" in the object caused by over-extruding.