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msurunner

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Posts posted by msurunner

  1. I have heard moisture content can have a large affect on PLA thermal characteristics. I have never documented it really, so I can't speak from experience, but perhaps that is what's happening. Your roll arrived nice and dry with a moisture eater inside the packaging, but after sitting out, it has absorbed some moisture and is raising the melt point of your filament? I would say try printing it at the 240? I know many people are afraid of higher temps, but as long as you are maintaining a feed rate and don't have excessive retractions, you should be more than okay at 240.

     

  2. ^^^If I were printing this commercially I would break it into three models. I would separate each of the main pavilion roofs and print them vertically as the curvature doesn't create a massive enough overhang to cause problems and just use support for the smaller enclave roofs. I would also hollow out much of the base to save plastic AND help with warpage. Just leave a couple of webs in there so it is kinda Lego-esque on the bottom.

     

  3. I would say the eight black ones are fine, as you really don't need a thread on them, they are just acting as standoffs from the frame to the motors. Being 11 and not 16 mm sounds better to me anyways and you would definitely need 8 of them for the motors...

     

  4. Your filament settings are probably fine (packing density and diameter). As for flow rate, that is a holdover value. It's derived from steps per e, but it isn't steps per e, if that makes any sense. The transition to step based volumetric values allows for greater accuracy and some hardware is lagging a bit. With regards to figuring out your steps per e, this discussion went about detailing the process you can do to figure it out. You can then go to File>Preferences>Steps per E and change your value there. http://umforum.ultimaker.com/index.php?/topic/1647-extruder-calibration/

     

    As far as a "safe" value of steps per e, mine's at 855.

    My next suggestion would be to partially disassemble your hotend. This is just from my experience, so take it for what it's worth, but I also haven't had any plug issues. When I say partially disassemble the hotend, this is what I would suggest doing. Unscrew the four long containment screws that go into the aluminum block. This will allow the actual nozzle assembly to move away from the bowden tube. Then simply push another mm or two of the bowden tube through the coupler and reassemble it. When you reassemble the hotend, your aluminum will have a slight gap from the wood. You don't want a massive gap, but a small one is good. In a nut shell, this just allows for a bit more of a pressure fit from bowden tube to PEEK/PFTE, hopefully preventing the oozing to start a donut, as the donut turns into a plug.

     

  5. You have 8 screws needed for the side motors, so that would be what I would go with, though I didn't know they were that long (mine's an older one)... The white ones are for the electronics on the bottom, both as spacers and acting as couplers if memory serves correctly.

     

  6. I am always hesitant to recommend tightening the belts more. They need to be tight, but there's definitely more forgiveness there than elsewhere, and it's all too often used as a lazy answer for another problem in the system. Over tightening them is a serious possibility and it can lead to issues with pulley slippage and stepper resistance/heating. Are your holes irregular or do they appear to be generally round? If they are pretty dang close, I would check pulleys and what not before tightening the belts and I would only do it in small steps. Also, the small belt tensioners you can find on thingiverse work great for belt tension, as it's usually the small ones that end up pulling the stepper motor up the frame and loosing tension. The tensioners require that a bolt turn, which is awesome. I have had students working on the printer for months now and haven't had to adjust tension once.

     

  7. Something else to consider when getting plugs and directly related to back pressure would be if grinding is a result of a plug, or a plug the result of grinding. When you examine the bite surface for the hobbed bolt, it's not particularly large being that it is a straight bolt, but the teeth are quite sharp. When you are experiencing excessive pressure, it can exceed the capabilities of the bolt pushing the filament, whereas it is quite capable of cutting a path in the filament. Do this once or twice, maybe not an issue, but it certainly doesn't take long to create a grind spot. Then you have idle filament and your heat begins to flow up the hotend towards the PEEK. The fact that you are getting Bowden tube movement signifies to me that you do have excessive pressure. There are two ways to combat that and illuminati stated one, slow it down a bit. The other is contrary to common thought processes, but to up the heat. I have one color of my PLA filaments (not a UM one, but PLA nonetheless) that I have to run at 250 to print at 60 mm/s. As long as you are shoving filament through it, it shouldn't be major issue running a higher temp. You start to have issues in printing with thin layers and slowly with larger retractions.

    SO, in summation, bump it up to 220/230 (temps I printed at with UM filament) and give it a go. What's the worst that could happen? You get a plug, like you are often getting, and you disconnect the bowden tube to remove it. Also, I'd be interested in a picture of your hotend, particularly one showing your aluminum plate...

     

  8. There's a known interference issue with the SD card reader and the display. Often popping the card in and out resets the display. Obviously in the middle of a print that would be hazardous, but I've never noticed this to happen. To be fair, though, I'm not running it connected via USB as well. Are you still doing this, or have you gone SD only?

     

  9. Your retraction settings must not be dialed in if they are on. Check to be sure that the temperature, speed, and retraction settings are the same with both prints. The extra stuff is bits of plastic dripping out of the nozzle as it moves.

     

  10. I am looking to do a bit of editing surrounding my Bertho upgrade and I didn't want to start from scratch... I had a hard time sourcing some of the bearings that were thin enough to fit in the slot without causing interference on the side pieces. I quick fixed it by tossing a set of sandwiched washers in between the plates, but that has some issues with it as well, so it's back to the drawing board a bit as the tinkering continues. So basically, what I'd be looking for would be the feeder upgrade. I pulled the others and separated them, but the changes in the pressure plate are unknown at the moment.

     

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