gr5

Usually it's better to push them through than to take the bowden off. Each time you take the bowden off you are in danger of scraping/damaging it with the thin metal blades that hold it in place.

Having the motors stick out the sides of the UM makes for more things to bump into and your motors mean you have to position the UM farther away from any walls and it's uglier. And the short belts work fine for me. If you transport your UM often you will be glad the motors are out of the way. However I've been thinking of moving mine to the outside (but still using the belts). It requires no extra hardware, no holes drilled, just swap the X,Y direction bits in software (or in hardware jumpers).

Photo please.

mac or pc? Try another machine maybe? I've had trouble connecting before - but it was fine after I power cycled the arduino. When you open device manager and plug in the usb to the arduino it should power up the arduino in that moment and the device manager listing should change after a few seconds. Does it add the new device in the list of unknown usb devices or in the list of COM devices?

For a large part you don't really need the side fans as each layer has plenty of time to cool before you start the next. So I suppose you could steal the connector for one of the side fans and use it for the rear fan. But note that if you disconnect one side fan, then neither will work as they are in series like the old Christmas tree light bulbs such that if one is broken they all go out. The rear fan normally comes on the instant you turn on power - even before the lights come on.

Also check "fix horrible" "A" checkbox.

I recommend maybe power cycling your printer Arduino before printing. Like Illuminarti says, it's probably remembering the position where you last printed and backing back up to the beginning with the extruder and doesn't know that that filament is gone now.

Well you can't include the enitre piXdiameter area because the UM prints in straight lines and you can't include the area you just printed. And you probably shouldn't include the area up ahead that you will be printing soon. So I think it's more like two hXn rectangular openings or 2 x h x n instead of 3.14 x h x n. But there is "more" resistance near the edges - I don't know what this effect is called. Anyway I agree that by the time you are at .1mm layers, printing more than nozzle width is going to be tough and so you have to print slow or just don't do it.

You just turn it. It has a plus-shaped slot so you can use a small phillips screwdriver. It's pretty obvious when you take the ulticontroller apart. But I wouldn't do this until you are sure the arduino is working through the USB.

I recommend the defaults: .4mm nozzle, 15% overlap, 20% infill. 50% overlap is okay, but I like 15%. 100% infill is too much. Better to set the shell to 30mm. That does 100% infill but with a safer pattern. .65mm nozzle - not sure how that will come out. I never tried it. It *should* work as long as you print very slow. But .4mm makes more sense. But I also have problems getting parts designed by other people to fit.

If you set nozzle width to .8 instead of .4 it changes several things. One thing is it outputs twice as much plastic (e.g. 200% flow). Another is it spaces the lines farther apart (.8mm apart instead of .4mm apart). A third thing is that it moves the head further from the edges when printing. You probably don't care about this but let me explain anyway: if you print a 10mm cube with .4mm nozzle, then it actually prints the cube .2mm smaller on all 4 sides to account for the radius of the nozzle. So the path of the gcodes will be 9.6mm by 9.6mm resulting hopefully in a 10mmX10mm cube. Same for interior holes and all edges - the head is moved towards the solid part of the part by .2mm. If you set nozzle to larger values it compensates further. Anyway, you could try increasing flow but not increasing nozzle size if you want. What do you mean by "not fitting"? Parts can be out of tolerance for many reasons. The biggest reason is shrinkage but there are other issues. Pictures? Usually if I make a part with important tolerances, I often just print the first layer, then measure the important distances, and then go back to CAD and adjust the model and print again. There is no simple formula to fixing these distances but the more you design and build the more often you can get it right the first time. You can even remove the "elephants foot" by printing the bottom few layers with a chamfer. http://en.wikipedia.org/wiki/Chamfer

If the head is .2mm above the layer below and you are extruding at 100% then there is just enough room for a .4mm wide bead. But if you try to extrude 200% flow or .8mm worth of plastic for a .4mm bead then you have to squeeze that plastic out through a .2mm crack which means higher pressures in the nozzle. The plastic has to go through a .4mm hole, and than an additional resistance getting out through the .2mm crack on either side. Typically on my first layer both my UMs won't output more than a .4mm wide bead no matter how much pressure there is. This is more true if the first layer is only .1mm above the print bed. This tells me you need quite a bit more pressure to get that .8mm wide trace over a .4mm wide trace. If you are printing with .1mm layers it's much worse (much higher pressures).

Those voltages are good (19V and 12V) just the way you said. You can buy a new arduino quite inexpensive. $18 including shipping in USA. That's something like 12 euros. But first I would do more testing - you need the arduino driver installed. You can get it by installing Cura as the Cura installer also installs the arduino usb driver. You don't need power to the arduino as it can get it's power through the USB. Do any lights light up when you plug in the arduino? Do they flash/blink? Does your computer make the "usb sound" when you plug in the arduino? (the same sound as when you plug in a camera or iphone or any other usb device). Do you have windows or mac? The other issue "fading to blue" may be unrelated - the ulticontroller has a potentiometer that you can turn to fix this usually. It's easy to spot but you have to take all the wood off first.

Read the post 2 posts up please. The build plate is VERY simple. 1) Is it reading the correct temperature? Because the problem could be with the thermocouple which reads back the temperature. Room temp is around 25C so if it is reading 200C then that's the problem. 2) More likely it's reading 25C but not heating up so the wiring is probably bad. Like Robert said, check the wires at the build plate. If you have a volt meter, it should get to a significant voltage when turned on - something like 12V or 19V or 24V? 3) If this doesn't resolve the problem (if there is no voltage or if the wiring seems good and tight - not loose like Richards, then put your UM on it's side and remove the larger bottom cover. It's only 2 bolts. Very easy. The heated bed wires go where it says "heated bed" on the circuit board on the bottom of the board in this picture.

I would have predicted same quantity of clicks but since everything is slower it would happen less often in a given minute. But swordriff experienced something different. You're going to have to experiment yourself some time I guess. The UM2 is new for all of us and it is making the "clicks" more obvious so we are learning new things about under extrusion.

Don't know but someone else might: 1) Turn off your machine. With the power off try pushing the head back and forth in Y direction. It's safe to do this even when powered on but easier when the servos are off. Does it make the same noise? Or a similar noise? 2) Please take a short (10 second?) video of the issue so everyone can hear it.

Illuminarti - if for example flow is at 200% and you print something normal, you are likely to get those kick backs no matter how slow you go.

I believe you. This is possible and makes sense only if flow is too high or if cura is extruding for more than a .4mm nozzle (1mm in your case which is like 250% flow). But when spiralize is off and flow is close to 100%, you actually get less "jumping back" with lower speeds (or higher temperatures). Decreasing feed rate slows down all 4 Axes: X,Y,Z, and E. So it slows down the E, or extruder as well as X,Y. This in theory shouldn't reduce the "jumping back" except that the problem that causes "jumping back" in normal prints is that the pressure in the nozzle gets too high and the nozzle can only extrude a certain amount of PLA in a given time. I have to admit though that the "jumping back" feature of the UM2 extruder is still new for me and I've only been using it for a few weeks and I'm still learning much that was not so obvious on the UM1. When the UM1 under-extrudes it is not so obvious! The jumping back is instant feedback that something is wrong. Did you seem my curve that showed speed versus temperature on the UM2 that finds the limit where it does the "jumping back"? http://umforum.ultimaker.com/index.php?/topic/3418-um2-extrusion-rates/ I think I will have to completely rewrite that post some day as I've learned some new things since then but overall I think it is still useful.

Thanks for the post. If the extruder is making the "chuff" noise and slipping backwards, you should instead slow down the print. The nozzle can only extrude a certain amount of PLA per second. If you are getting the "chuff" sound you can fix this by either slowing down the printing, or raising the temperature (but that might cause other problems) or print thinner layers (less plastic per second). Decreasing flow is usually not a good idea but I'm sure it worked for you! Still if you could print at 100% and print slower you might get a better result. HOWEVER I also note you have spiralize checked and you have the shell thickness set to 1. This causes a similar setting as if you set the material flow to 1mm/.4mm or 250%. So setting material flow to 40% then brings this back to a .4mm bead with 100% flow. What you posted makes sense and it will work but it's a little strange to set the thickness such that flow is 250% and then compensate by setting flow to 52%. You could have just set the wall width to .52 instead. I think it's a little easier to understand if you keep the wall at .4mm or you keep the flow at 100% and only change one of these parameters at a time - not both at once.

Not really. The nozzle and the heater block are a single piece in the um2 and you have to remove the heater and the thermocouple - both of which can potentially be stuck and either could be damaged if removed too roughly. However your UM2 is still new and they might come out easy. Much easier to do is to take the head all apart and clean out the hot end from the "top". I suggest you order some acupuncture needles now so you will have one for the next time.

If when printing so much PLA is leaking out that it is dripping onto your print, then you can either add plumbers teflon tape in the threads or you can tighten things more. But my aluminum block rotates a little bit (hits one of the 4 big vertical screws though).

Yes it's fine. Make sure it can't rotate enough to touch the fan shroud as it will melt. If it *does* melt then repair it with kapton tape which can go up to something like 600C I think?

Some parts are too delicate to use a sharp blade. For those one needs a dremel. But it will melt the PLA unfortunately. So it is difficult but better than a blade.

If the gears don't have to *look* good but they need to function perfectly you can probably print very fast - say 150mm/sec and hot, say 240C. If you want them to look perfect you should print very slow, say 20mm/sec and cooler, maybe 200C. If you care about function over look, then you can usually print quite fast.

1) Look at the model in Cura "xray" view. If there are any red spots at all, cura considers that a problem. 2) If it's going to be a lot of work in your cad software to "fix" all the red areas (internal walls) then consider using the "fix horrible" settings. There are 4 checkboxes but you only have to try 11 combinations because A and B on at the same time is meaningless. 3) Also you may have an opening maybe? Somewhere on this level where the gap is? Or maybe your window panes don't connedt to the window frames. If you are going to try all 11, I recommend slicing very very thick (like .4mm or whatever the max is) so you can try them all quickly.