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  1. That looks weird. Something is going wrong with the slicing here, so you can rule out printer problems for now. Never seen this happen in Cura (nor in Repetier, but I don't use that a lot). You could download Cura from the Ultimaker site (it's free), and see if the same thing happens when you load the model in Cura.
  2. If these bits are caused by the slicer then you would definitely see it in Cura's layer view. If you don't see anything like that there, it is not caused by Cura or a "faulty" model. In that case the problem is in the printer, mechanical or firmware. Or perhaps it is caused by cheapo Chinese PLA, but then I would expect to see a lot of other shit in other parts of the model as well. Still, don't use that stuff. Always get good quality PLA if you want good quality prints. Another tip for delta printers: accuracy of those is worse in the centre of the platform, and better towards the edges...
  3. Never seen anything like that on Ultimaker with Cura, so I doubt this is bad slicing. Good to know, and PERHAPS this might be causing it: a model of a thin walled cylinder is never 100 % round. The cylinder has sides and although it might seem round when there are many sides (120 or more for instance), it actually isn't. Curves don't really exist in a digital system, they are always "steps".... As a result, the thickness of the wall is never exactly the same all over. This is always the case in all curved walls. So if you have a straight wall that is exactly 0.4 mm thick, when you put a cur
  4. PS I just noticed that gr5 already mentioned that this could be the cause, back in june. See page 1 of this thread, I quote: "Another solution (maybe) is to use a copy of Marlin that uses "slow fan PWM". You can do that by unchecking the 4th checkbox from the bottom here. This won't eliminate the problem but it will cause less frequent spikes in the voltage so that hopefully you get less frequent "bad temperature" readings. http://marlinbuilder.robotfuzz.com/ " (It's the 5th box from below actually, if you want to try it out.) Somehow I missed this first time around - too busy replacin
  5. Quite a while since last I posted on this thread, but here's an update. I FINALLY found out that the temperature swing is caused by a firmware setting called "fast PWM". This setting causes much more PWM noise when you print with any fan speed other than 0 or 100. This noise interferes with the thermocouple signal. I made a version of the firmware with the "fast PWM" switched off, and now I only get very moderate swings in the temperature reading (2 or 3 degrees max) and (more important) the actual nozzle temperature actually stays in the neighbourhood of the temperature reading, instead of
  6. In case you're wondering: the smoke accident happened when I was tinkering with the print head, and I did a test print without clamping down the plug of the thermocouple (and probably didn't plug it in properly). Plug came loose, the electronics were getting no temperature reading, and that caused the heater to stay on. By the time I stopped it and stuck that plug back in, the temperature was 320 degrees...and that took a while, so it got hotter than that. Big PLA smoke cloud in my shop. So this is not bound to happen very often, however I understand that the connecting wires can break someti
  7. Agreed, all electronics can cause fire. But this machine also has an electric heater that is melting plastic, quite different from most other equipment I would say... People WILL be leaving their printer unattended. Or am I supposed to sit and watch the machine when it is doing a 24 hour print ? I can watch it for hours (printer meditation...) but I need some sleep as well. And I did not suggest building a smoke alarm into the UM3. The system I described above would hardly add to the cost of the printer (if at all), and would definitely make it MORE safe. 100% safety was not what I asked fo
  8. That's the one. So printers CAN burn your house down.... I wonder how often this happens, looks like chances are very low, but still... some people win the lottery as well. All the more reason to add the function as described above to ALL printers from now on. It should be simple. In the meantime I'll be waiting for that Smoke Signal to arrive... thanks for the link.
  9. PS Google only comes up with some patents for "smoke detector power cut-off systems", but apparently there's trouble from insurance companies. Can't find any such thing on the market...
  10. Still very happy with the UM1... what a great machine, and many ways to make it work even better, which seems a lot harder with the UM2. I really like the ability to manually move the feeder wheel (while starting prints, changing filament...), which you can't do on the UM2. Would be nice if that was possible on the UM3. Or else some dedicated buttons to do this. Could do with another 2 buttons to quickly lower/raise the platform. For safety it would be great if there was something built into the electronics to check the behaviour of the power going to the heater. It is possible to get a mal
  11. @UltiArjan: nice thread about that exchangable nozzle. Very interesting, but not very accesible to most users yet, I guess...A good one for the "what do you want on the UM3" request ? And yes, 120% flow can be good for watertightness. However I have noticed that when the flow gets too high this actually makes the bottom leaky again, as the upward ridges between the print lines become too high, creating more pores again. Also, very high flow can make the outer edge of the bottom layer look ugly, so I often set the TweakAtZ plugin to increase the flow gradually during the first few layers. An
  12. @UltiArjan: Nothing wrong with a big nozzle, but I assume the majority of UM users don't want to be bothered with changing nozzles (and releveling the bed) for each print... @Kirash4: please read my reply again: you can have the bottom as thick as you like (up to 20 cm ) but when you set the shell to 1 mm (using "spiralized") while using a 0.4 nozzle this means that your infill lines will be 1 mm apart, and there is no way you can extrude enough PLA through that 0.4 mm nozzle to get that bottom watertight, no matter how thick it is. Apparently you can file down the nozzle to create a larger
  13. That's funny... I tried that trick some time ago, but it did not work then. I have checked, and indeed it does not work in 14.01 (which I have used for most part of last year) as that one also produces "inside skirts" (pretty annoying...) but it DOES work in later versions. Never noticed those inside skirts had disappeared, as I had set all my skirts at quite some distance around all objects with cutouts since then, because that removed the inside ones. So now I can put those skirts back to 1-2 mm again, which is nice. Thanks. Still, would be nice to have a checkbox for "inside brim", so we
  14. Using the "spiralize" function, the wall of your cup will always be a single layer, because the spiral starts at the bottom and then spirals up on top of itself, like a coil/spring. So you should usually set the shell to the same size as your nozzle (standard is 0.4 mm) when printing spiralized. You CAN increase the wall thickness by using a higher setting for the shell when using "spiralized". That way there will be more extrusion, so although it is still a single layer, the extra extrusion will be forced out of the nozzle and will be spread out sideways by the "shoulder" of the nozzle (= t
  15. Check whether you have set the right setting for "combing" in Cura 15, as it doesn't properly copy the settings from ini files made with earlier versions. Not sure whether it is causing this problem (probably not) but it's worth checking anyway... My intuition tells me it makes more sense to do the shell before the infill, as there are bound to be small imperfections at the starting points of the infill lines (blobs). These will be in the way when the shell is built, and the shell will be pushed outward at these points. When you put down the shell first, these blobs will be stuck against
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