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technicality

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Posts posted by technicality

  1. The fan cools the topmost layer to avoid the printhead 'pushing in' the next layer (because it is still soft).

    Print small-diameter towers or overhangs without fan are hard to do; the top layer will curl up at the edges and get the printhead to take the print with it or snap it off.

  2. The green and blue printers both printed 100 over the weekend. What we do is we have a special GCode script that uses the printer head to push the object from the platform.

    Whoa awesome! Can we get some videos of this script in action?? Makerbot made some seriously awesome time-lapse footage of an ABP-equipped thingomatic printing out all the mendel parts one by one. Never mind that the ABP never worked for anyone else, it was a pretty awesome vid and I bet you'd get a lot of customers when they see that.

    Maybe you can put a little printed bulldozer on the side of the print head so the robots are removed more successfully?

    Here is an early attempt by me:

     

    It uses the front left screw to press against the robot.

    I never got the Gcode to loop well though (M41 did not work for this) so I just copy/pasted the appropriate gcode several times.

  3. We have had some succes using the print head to push a finished print off off the bed and then starting a new one. We use a different tape than the standard blue one for this: Sigma ProGold. It sticks a lot less, but still enough when printing the first layer at moderate speed and with the fan off. When cooled it just pops off. We use a switching routine and copy/paste the 'main' g-code + switch a couple of times. See

    Our switch code: (printer just printed our part, is on top layer height of 34 mm)

    G1 F4200; set rapid speed for travel move
    G0 Z44 ;go up (actually just final print height + 10mm)
    G0 X136.9 Y150 ; go to x-y spot, x is chosen to have the head push with the bolt on which the fan is attached
    G0 Z4 ;move down
    G1 Y0 F3000 ; push print off with movement speed 3000 mm/min

    The code then looks like this:


    • [*:14hr3q3m]printer start code
      [*:14hr3q3m]main gcode
      [*:14hr3q3m]switch
      [*:14hr3q3m]main gcode
      [*:14hr3q3m]switch
      [*:14hr3q3m]... repeat
      [*:14hr3q3m]end gcode

    We are still working on this (not a priority atm though). Some points:

    • [*:14hr3q3m]We use manual gcode editing at this point
      [*:14hr3q3m]We made an error with applying our tape, so the print got stuck at an edge and sprang away
      [*:14hr3q3m]We haven't got a good first layer (even with skirt), possibly because of a retract move at the end of print or oozing (Z-height is no problem, you correct this for the first print anyway)
      [*:14hr3q3m]Not sure about relative/absolute positioning and how we can use it best

  4. Just press down the moveable part of the coupling, keep it pressed and then pull the tube out. If it doesn't come out with little force, try wiggling or a push-pull.

    You're more likely to break the (already faulty) bowden tube than the coupling, so you can use quite some force - be careful of the wooden part breaking though!

  5. @technicality: I was informed I probably have a "bad" bowden tube, so I'm getting a new one. The prints are reasonable, and I wasn't informed how "bad" a "bad" bowden tube is. (I'm not expecting it to turn zombie on me....)

    (what's a classic bowden plug? Googling for that phrase gives hits like:

    )

     

    I just made this animation that explains the 'classic' bowden plug:

    http://wiki.ultimaker.com/images/Bowden_plug.gif

     

  6. Hi Guys,

    Here is my second print, and the first one that's worked well. It's an owl (

    http://www.thingiverse.com/thing:18218

    ).

    I scaled it down to 50%, and printed through Cura on normal quality.

    photo%20small.jpg

    The only thing is that my temp is set to 218C on PLA, seems high, but the print quality is great.

    Should I try dropping it down a bit, or is this ok?

    Thanks all.

    Your print looks very shiny, an indicator of high temperature. You could safely drop it. In my experience the first thing that will go is layer bonding and after that you might have extrusion problems (slipping filament) because of high forces. Just lower the temperature so you still get good layer bonding.

    Too high temperature will not necessarily be bad for your print, but it might cause more stringing or problems because of heating up the filament too much and it plugging your PFA tube.

  7. The classic bowden plug is when there is still a gap between the PEEK/brass and the bowden tube. Molten plastic will come up (because of backflow:

     

    ) and stick to the PEEK. Because the PEEK is much cooler than the brass, the PLA will also solidify. EVen more plastic comes up, sticking to the other cooled plastic and thereby creating a plug.

    With ABS there is no backflow.

    Edit: there are some other options for slicing. You can use Cura, which is a nice front-end for a (modified) skeinforge. It uses printrun to communicate with the machine. And some people are using KISSlicer which seems to generate top-notch results so far.

  8. I had the same problem, but then i turned up the potmeter (current setting) on the stepper drivers. I measured it and put them on 1.1A and it solved this issue for me.

    In my experience only machine which are running less smoothly have this problem.

  9. The picture quality isn't the greatest but it's the best I could get right now. The chamfer looks fairly deep to me but the white clamp only sticks up enough to get the horseshoe clip on. I couldn't think of a quick fix if the chamfer is in fact too deep - any suggestions? The grey in the picture is some JB Weld that I tried but it didn't stick to the PFA. I think that the teeth in the white clamp are starting to get stripped. Is this a standard part I can buy here in the states to swap it out? What would I call that piece?

    I can't see the image you are linking; because it is on your computer we cannot see it. You could upload it to http://imgur.com/ and then link it here. But if as you say the horseshoe clip fits snugly then this probably will not be your problem. Do you own any calipers to measure the outer diameter of the PFA tube? It might be too small...

  10. Also, when you screw it back into place (with the bowden tube at the correct depth again) it helps to draw a line with a waterproof marker to indicate how deep the tube is put into the PEEK. So if it hangs again you can easily check for the bowden pop-up just by looking at it, instead of having to take the assambly apart again.

    Regards,

    Bart

  11. Is the diagonal cup supposed to be like that?

    Glad it worked out for you. As far as I know the motors themselves (coils, magnets, bearings etc) are rarely faulty - I am suspicious of the wiring though. It could be that the connector is not on properly or connections in the motor are borked. Did you return the motor or do you still have it?

    In the latter case, could you measure the resistance in the wire pairs? Maybe one of the pairs is broken. Checking for this would help in isolating the real problem.

  12. The best thing is to measure your filament (both along and perpendicular to the spool axis) with (digital) calipers. It's possible that one of these values is too large - it shouldn't be more than 2.90mm. At 3.00mm or over you will get a large amount of friction in the bowden tube, causing problems like the one you're having right now.

    I don't think you could deform filament to an oval to this point without thinking twice about the force you're putting on the screw. You will know that you're forcing it then.

    What do you mean by 'the printing head is getting stuck'? Does the extruder grind on the filament? Maybe you're overextruding (slightly), causing pressure in the filament and giving the feeling of a plugged hot-end. This is most noticeable in large filled areas (like the first layer of a big print) - but first i'd check your filament diameter. If it is in fact too big you'll also be overextruding (because you push more volume of plastic per extruder step).

  13. Im not familiar with the 'IKEA Ultimaker carrying bag', but at least it looks more professional ;)

    It can handle the weight of an UM + roll of PLA (+one more, plus power adapter + UltiController) easily, without any sign of straining or breaking. The design does not rely on layer adhesion for strength.

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