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avogra

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Posts posted by avogra

  1. Lately, my Ultimaker2 refused to print the slightest string of plastic! In desperation I called the Ultimaker support and guess what: They promised to send their best men! 2 hours later the doorbell rang and Mr. Ultimaker himself entered, followed by some other guy. In no time, they revealed the root of my trouble: The nozzle was clogged! Some acupuncture needles and atomic pulls later my Ultimaker printed like never before. Thank you, Mr. Ultimaker!!

    5686e45361839.JPG

    Link in Print Section: https://ultimaker.com/en/community/prints/2085-entry-for-community-contest-part-7

    • Like 5
  2.  

    @Labern, will do that. The wiring is a mess.

    @Skimmy, thanks! No resistors needed? Smoothieboard only does PWM as far as I know. However the frequency is adjustable. But as the corresponding variable is measures in milliseconds, I doubt it will do more than 1 kHz.

     

    No resistors needed, as long as you don't put all 10 caps parallel to the fan ;)Worst that could happen at this point: board resets/freezes cause of the voltage-drop. If you add caps, take the highest frequency possible. Rule of thumb is like "keep it above 100Hz".

     

    @Skimmy, i think it is dangerous to attach capacitors between a pwm output and ground without a resistor or coil in between. In theory this is a short between the internal capacitors and the added capacitors each time the tranistor turns on. The external capacitors will have discharged a bit (or be empty at first turnon) and a very short pulse of high current will flow from internal to externally added capacitor. In practice, the current is limited by resistance of transistor, connectors, inner resistance of capacitor etc. but still the transistor might be used beyond its maximum ratings.

    This can work out but might as well end up in a dead transistor. Depends heavily on the electronics board, type of capacitors, transistor, internal capacitors etc.

    The royal solution is a properly calculated coil with a free wheeling diode between pwm output and capacitor, which gives a simple buck-converter. A sound but less efficient alternative is a sufficiently large resistor, but this will reduce the maximum output voltage.

  3. if I remember right, someone said, that in the new cura you can assign different profiles for different layers. or is it planned but not yet implemented? that would match your last suggestion quite well.

    you often have no distinguished top layer, look at the treefrog for example.

    • Like 1
  4. Your modifications look really simple and effective! I didn't hear about the spacer for the hotend fan before. Will certainly give it a try!

    You could print Roberts Feeder mirrored in order to mount it reversed. What else I have seen is, that people don't mount their spools to the spoolholder but put it on a stand to the left. This should have the same effect as reverse mounting and you also gain easier access for when you want to change filaments.

    My printer passed the extrusion test up to 10mm^3 out of the box. I have it for 4 weeks now, so maybe Ultimaker has improved some of your points in more recent units? Or I just had luck with my unit. I already heard, that Ultimaker is improving their machines quietly over time. Are those changes publicly available somewhere?

  5. I might have found another bug:

    when i'm in "topics" view with some unread posts (e.g. blue bars) and press the "mark as read"-button/text, the page reloads with the same posts still marked as unread. when I do the same in the "categories" view, all bars are removed as I would expect.

  6. I think I have found the reason: this might just be shrinking: When the first solid layer is printed after the walls, it will consist of 90% overhangs. This first layer will cooldown and can easily contract, because it only has to bend those walls a bit. The next layer will see much more resistance, as there is one solid layer beneath. So within a few layers, there is hardly any more shrinking and dimensions are as intended. Then the next walls are raised perfectly straight. When the first solid top layer is printed, the same happens again.

  7. Oh, I didn't notice as I'm always in topics view instead of categories. There it's like in the subpages.

    Just now I discovered, that you can put a filter to only show unread messages and even save the filter settings. Very cool too!

  8. I had my first larger print this weekend. It is a an air guide for an adaption of the crossflow approach for the UM2. It is quite okay except that at the edge of the buildplate the walls between the air channels are all sloped towards the center of the buildpate.

    IMG_20150922_211122.thumb.jpg.cd5f1030a1b6def56c3641e1700e25b0.jpg

    The first full horizontal layer seems to restore dimensions. On the second level of channels the same happened to a less extend.

    The inner walls are 0.8mm, the outside walls are 1.6mm. I had to print it 45° rotated to fit on the plate.

    Filament is Colorfabb leaf green. Settings were 50mm/s, 100µm layers, 0.8mm walls, 15% infill, fans 100%.

    My first thought was, that the inner walls are only 2 lines, one going front the other back, so there might be some torque forcing the walls to bend. But that would make them all bend in the same direction and at the other end of the part, they are also bent inwards.

    Any ideas what has happend?

    btw., the function is lousy :PAirflow is quite uneven across the length and mainly dictated by where the radial fan blows. Next design will put much more resistance against the flow and instead of straight channels I want to try a kind of a streched nozzle als used in some airdoors by teddington.

    [Edit:] I forgot to write printing temperatures: it was 205°C / 60°C

    IMG_20150922_211122.thumb.jpg.cd5f1030a1b6def56c3641e1700e25b0.jpg

    • Like 1
  9. After many months of lurking and reading I now have a brand new UM2 along with some rolls of Colorfabb filament. I'm still in this early stage of excitement when you get a new toy ;-) Up to now I printed most models which were shipped with the sdcard, a 3dscan of a gardenturtle and more useless stuff, mainly to impress myself and others :-p First own design was a simple bracket to mount a cheap multiple-socket-outlet under my desk with screws. Worked out well.

    One impression is, that the cooling might be better, as many have discovered before me. The next step will be an adaption of the crossflow approach by @foehnsturm. I hope to find a way to mount this inside the UM2 without having to cut the sides. Instead of the crossflow fan I want to use a PC-slot radial fan which should fit between build plate and the right side. I will write in the crossflow thread as soon as I have some results.

    My main motivation to buy the UM2 was realizing technical designs, which I couldn't build up to now. Top project will be a spectral photometer to analyze the composition of different light sources. I have everything ready except for the fixture of the optical elements and the mechanics to scan through the wavelengths / colors.

    I see that it takes quite some time to get used to this business, no matter how much you read beforehand. Ideas like building the magnetic toolchanger are far out of reach now that the box sits on my desk. And I will give myself some time before I start the spectrometer. Anyway I'm looking forward to it !

    IMG_20151004_231222.thumb.jpg.9ecadb0c7efde5ce7e98eb8310d9419e.jpg

    IMG_20151004_231222.thumb.jpg.9ecadb0c7efde5ce7e98eb8310d9419e.jpg

    • Like 5
  10. Same opinion here. Please give us a single page with unread posts and a button "mark all as read" to remove posts, im not interested in. Each link should jump exactly to the first unread post of each thread.

    In the old mobile version, these were the features i used 99% of the time.

    • Like 1
  11. Hallo,

    jetzt ist es soweit, ich muss auch einen haben ;-) Und zwar einen Ultimaker 2. Mir stellt sich eigentlich nur noch die Frage, ob ich direkt in den Niederlanden bestelle oder in Deutschland z.B. bei Reichelt oder iGo3D. Letzteres ist unkomplizierter aber spricht auch etwas dagegen?

    Viele Grüße!

    Alex

     

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