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kris

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Everything posted by kris

  1. I think friction has to be considered as well. Teflon has very little of that...
  2. Looks like inderextrusion. Maybe you have to clean the nozzle? I mean take the extruder apart and really clean it. I believe if the temperature is too high you will burn your PLA and residuals will get stuck in the nozzle and clogg it. I usually have this problem if I switch from PLA to ABS. So now I pnly print ABS.
  3. Thanks. I was actually inspired by your work. I have closed the rear with a cloth, similar to a curtain. Much in line with the minimalist approach ;-)
  4. Leon- I did suffer from similar problems in the beginning. Here is what I did to get things running: - I only print ABS. If I switch back and forth between PLA and ABS the nozzle will clog at some point. My guess is that residual PLA is incompatible with the higher ABS temperature. After you have cleaned your nozzle, my suggestion would be to stick to one type of material. - Innofil ABS prints allot better than UM ABS. To me it seems as if Innofil ABS filament is softer and the feeder wheel has a much better grip on it. My simple conclusion is that the type of material you use matters. My knowledge here is limited (I have so far only printed UM and Innofil), but maybe someone on the forum can give us additional tips on that. - The extruder has a few design flaws making it susceptible even to tiny variations, it is not very forgiving. I have switched to the glass filled insulator, but I cannot say if this is an improvement. So far I hadn't any problems with it. - In my opinion a closed chamber is a must for high quality prints.
  5. Ultimaker provides some glass fiber reinforced teflon spacers. A few thoughts; Ceramics will change the entire heat flow in the nozzle and most likely also increase friction.
  6. Hmm die Meinung teile ich nicht. Mit Innofill ABS komme ich prima zurecht. Auch hat sich noch nix verklemmt. Kann die Ursache eine andere sein?
  7. Did a set of eight 170mm wheels for an 88mm Flak. Material innofil black ABS, layer 0.25mm, no fans. Each wheel has a weight of around 200g (hollow). Part of the rim and the shafts are printed separately with 0.1mm. Approx. 120h in total, plus 6h for one that failed because stupid me had to try out another glue stick. At first I used ultimaker black ABS. Turns out the innofil materials prints allot better.
  8. I had exactly the same problem once. Nothing would help, until I completely took apart the extruder and cleaned it of all residual material. There might be some contamination that travels up and down the nozzle. Actually you only have to clean the nozzle and the PTFE bushing.
  9. I would unscrew the fans and the metallic bracket that holds them in place. Then you can bend the metallic bracket back to its original shape.
  10. Everything on youmagine now :-P : https://www.youmagine.com/designs/closed-chamber-green-house-um2
  11. The same happened to me when changing from PLA to ABS. Clogged the nozzle which led to heavy underextrusion. I had to completely take the extruder apart (carefully!) and soak the nozzle in acetone in order to clean it. Something happens when the ABS gets mixed with the residual PLA. I am sticking to ABS now.
  12. There sure is. Especially for large ABS parts a closed chamber is inevitable, see here http://umforum.ultimaker.com/index.php?/topic/5225-managed-to-overcome-warping/
  13. That is also a concern I had. But nothing has happened so far. For ABS I even use 110°C for the bed in order to avoid warping.
  14. Hi all Here is my version of a closed chamber for the UM2. The acrylic plates I used are standard sized and glued, hence no cutting required. I spent roughly 35€ on all parts. The rear of the top lid will be covered with cloth. The door closes with a magnet. I will add a rubber seal to the door and will have to modify and reprint the hinges. I also have plans to add an IP camera and hock it to the door. I plan on uploading all plans and material sources if there is any interest. Cheers Kris
  15. Did you always have this problem or did it occur suddenly?
  16. ABS extrudes at 260°C. What happens to residual PLA at that temperature if I switch from PLA to ABS? Could this potentially clog the nozzle? Just a thought... :-P Because I noticed many people experience the problem after changing material, including myself. So maybe there is nothing wrong with the hot end after all.
  17. Support removal was ok, cleanup and sanding a pain in the butt... I did the model mainly in Scupltris, with some help from Meshlab.
  18. Finished this print today (UM2): ABS white 0.1mm layer thickness 50mm/s bed @ 110°C in closed chamber fans off Sword & horn printed separately
  19. Wonderful. Also very interested in the results :-)
  20. Maybe this helps? http://umforum.ultimaker.com/index.php?/topic/5953-idea-on-underextrusion/page-2&do=findComment&comment=56951
  21. kris

    STL Dateien mixen

    Zum bearbeiten von STL Dateien bietet sich auch Meshlab an. Dann einfach mal nach Meshlab und 'join meshes' googeln. Gibt zahlreiche gute Tutorials auch bei Youtube.
  22. You might be correct. Would be interesting to try this out.
  23. My guess is that the current heat sink is in the wrong place. It is not efficient in preventing heat moving into the PTFE part. It is also too far away.
  24. I think if the heat sink touches the aluminium block that is not a bad thing. This just increases the cooling area. Neglecting the rear fan is kind of conservative I guess, since it will improve convection. Now that I think about it, I do not really understand the slotted aluminium block at the back. To me it seems as if it is too far away from the heat source. I think the new heat sink could replace that component completely and reduce temperature in the upper part of the extruder considerably.
  25. Here are the results. I ran a few different models to test out different ideas to knock down the temperature in the PTFE bushing. I did not take into account forced convection (from the fan). I achieved the best results with a heat sink at the top, as originally proposed. In addition reducing the contact area between the PTFE bushing and the remaining components helps. I managed to reduced the temperature in the bushing from 170°C to 110°C (model ptfe_v2_p). I measured the temperature a few millimetres away from the interface to the nozzle, because here the temperature is pretty much unchanged due to the proximity to the heat source. I have tried not to alter existing components, in an attempt to create a method that can be retrofitted. Currently the heat sink that I added does not fit into the setup. There is too little space. So it has to be reduced in size somewhat. Important to note: The TG of ABS is around 104°C. Previously we were well above that in the PTFE bushing which means the ABS will loose most of its mechanical properties before it even enters the nozzle. At the moment the spring pushes the bushing firmly against the nozzle. There will be a certain heat transfer. If we would allow for a little gap between these components the temperature in the PTFE bushing will remain around 100°C. See below. Not sure if that would create other problems. But sure worth a try. The bushing would have to rest against the steel nut. Feedback is most welcome
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