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destroyer2012

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Everything posted by destroyer2012

  1. Here is my opinion on this, as a user of UM1 for 2 yr and having modified the heck out of my extruder drive to get it to work reliably. Take it or leave it obviously. I think the knurled thing has to go. I was never able to get a good extrusion until i made my own hobbed bolt with sharp teeth and a larger diameter (using a metal "spacer" as the blank like the makerbot mk6 drive gear) I think the 'lack of space' for the spring to travel is actually a good idea. What this does is it creates a stopping point for the travel of the sprung idler. This means that if the drive grinds the filament because of too much pressure needed to extrude, it does not go on ahead eating away at the filament (as the spring idler presses it in towards the drive gear). Also consider the problem of force application. With a totally sprung idler (no stop) the spring is squeezing the filament towards the drive gear, in a direction it totally does not need to. With either a fixed idler (like the first wade's extruder) or a stopped idler, the pressure stops after teeth have been imprinted on the filament, because after that point you don't need to press on the filament even harder. Just another point on this: we don't need the drive gears to accomodate all sizes of filament. The bowden tube already jams if the filament is the wrong size. That is why a minimum travel of the idler wheel should be fine (in fact my extruder currently has absolutely no travel and it works great with ABS and PLA) I think the extruder needs a gear reduction. This allows you to use larger diameter drive gears which I think are absolutely necessary to have enough grip. The goal is to have the extruder motor start skipping before the filament shreds or the hot end gets destroyed. finally, other aspects of the filament drive subsystem are important to consider. For example, the length and ID of the bowden tube, the hot end itself (modified to minimize necessary extrusion pressure?), and of course the diameter of the filament you are feeding into the machine (forget it if the filament ever goes near 2.99-3.01mm). If any of those other things don't fit the specification then nothing you do to the pinch wheels will make a difference.
  2. Alternatively, just swap the axis direction in the firmware. I have done a similar thing in that I have enclosed my ultimaker completely using cut up oven bags to keep the warmth from my heated platform in. I think it definately helps, at least with PLA. I think the fan is still important because what you want is to quickly cool the plastic down to the ambient temperature inside the chamber. Commercial printers do this by basically being a convection oven. So you could keep the fan around the nozzle or mount a big fan on the bottom that blows all around the inside. You definitely don't want your plastic to stay molten after it gets extruded or else it will sag/move around after being printed.
  3. I read somewhere that the belts we are using are not intended for precise back and forth motion, only precise motion in one direction. Switching to belts with a more curved (and maybe slightly bigger) tooth profile like reprap does would probably be one good step to take. The curved tooth profile ensures that the teeth cannot slide on the gear pulley. THe next thing we would need is a good way to tension the belts, ideally with some kind of spring to literally apply tension to the belt (as opposed to the "stretch the belt till it's taut" method). This is the way all commercial 2d printers do it, and it allows the belt to be relieved of stress; that means no belt stretching over time.
  4. Thanks for taking the time to relate your experience! I think this will be very helpful to a lot of people
  5. Can you be more specific? How is it more difficult to work with? What did you have to do differently once you "got the hang of it"?
  6. 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?
  7. NOW if only we had the automated build platform! Then it would really be a factory wall. How many robots do you guys print at once on one of those UMs? I figure you could fit at least nine on each platform, maybe more. What is that box-like object sitting on the lower right blue UM in that picture?
  8. My general experience with ABS is just don't worry about cooling. When I print, I only turn the fan on for making perimeters, and even then only at half speed. I think the chamber helps a bit but it's really not hot enough (since I don't have a dedicated chamber heater/ convection fan) to prevent all warp, so you should be OK with a heated bed + no cooling on the part. I'm glad to hear those parts are solid! I wonder then if you can replicate the 2BEIGH3 results in terms of print flexibility/solidity http://www.instructables.com/id/Combina ... -Overview/ He doesn't even use a heated platform, and he also uses blue tape to make the nylon stick. Definately going to try to make a v3 nozzle myself.
  9. Those prints look pretty good I'd say! Are they flexible? How good is the layer adhesion? Can you make a replacement extruder gear with this stuff? If you are experiencing poor layer adhesion perhaps the answer is a higher extrusion temperature? Are you using a fan when extruding this? I know when I first started printing in ABS I was cooling it too much and all my parts came out brittle, so I increased the extrusion temp (240 now!) and turned down the fan and now my parts come out (dare I say) perfectly.
  10. SWEET CITY! Don't forget to put pictures of the items printed in nylon! Where did you get your nylon filament/feedstock?
  11. I don't think that professional 3d printers use valves, I think cooling is the way to go. A low thermal mass hot end with a thermal break and an active cold end would eliminate oozing. Just turn the extruder down 20 degrees when not extruding, and pull the filament up to the thermal break.
  12. You could try to drill out the stainless steel part in steps. First, use a #31 drill (3.041 mm), then 1/8" drill (3.175 mm), which should be plenty big for extrusion. Sure it won't be as smooth as a reamer but close enough? It's already got a hole in it so alignment shouldn't be too much of a problem. You might need some carbide drills though. Plus, you should only have to drill out the part of the barrel where the filament is still cold. Once it gets hot and liquid it will flow into a smaller opening. So maybe drilling only one cm deep with a 1/8" drill into the stainless steel part is more doable? Another alternative is to drill out a brass bolt to replace the broken V2 heater barrel, and then try to make a thermal break by filing down the threads in the right place. I might try to drill out some stainless steel bolts just to see how insane it is... MAY be doable at home? I hope so because this hot end seems like a really good idea
  13. Awesome! I have two questions though: 1) What exactly is your setup? Do you have the bowden tube float above the metal nozzle's cold end? Are you saying it is cool enough now to just insert the filament up top and not have it form a plug? 2) How fast is "max speed"? What mm/min are you feeding filament to the extruder? So it looks like all we need is an aluminum block to screw on above the heater block, and a heatsink+fan combo to cool it down? That's way better than water cooling, seems like I could make it with only a drill press too. Sweet.
  14. Adrian bowyer made a valve on his extruder back in 2008. See here http://blog.reprap.org/2008/08/extruder-valve.html The conclusion was, it's too hard to build it, and the benefits were later found to be attainable via retraction. Besides the valve hole makes it leak from two places instead of one. Ultimaker retraction is possible, we just need a better extruder with a bigger diameter hobbed bolt for better grip.
  15. Whoa you are turning the whole head assembly into aluminum? That's crazy! Isn't it going to become really heavy now? I thought you were changing only the hot end. Why is it necessary to change the entire head to metal if you are water cooling the hot end anyway?
  16. Just take the set screw from the pulleys on the driven axle and put them on the pulleys on the driving axle. The driven axle doesn't NEED to have the pulleys rigidly attached. I'm running without those four screws (two per driven axle) and it works fine.
  17. Sorry I guess since the version of marlin i downloaded from the marlin github had ultimaker specific settings and comments in it i figured it was leaning more towards ultimaker development now, but I see that's wrong. Well anyway a discussion here is as good as anywhere Just because something has more buttons doesn't necessarily mean it's more complex to use. I want buttons so I can switch to jog without having to go through three menus (Prepare>Move Axis>X). And it's so frustrating that the menus reset after like half a second, so if I'm trying to level the bed and take a bit longer to crank that screw I have to traverse the menus AGAIN to move the head back the other way. Another thing that might help is a "home" button so you can forget about resetting the menus. Or at least make that timeout a lot longer. This is, again, something I will never understand: If there's an ability to use more buttons why not leave it as an option? Maybe I just haven't read enough about the firmware but wouldn't it be cool to be able to enable different subsets of the firmware, one of which has X, Y, Z jog buttons and another one (for laymen maybe? Who is a layman ultimaker operator?) which only has that click-wheel. If you've ever used a real CNC machine you know the jog panel has a lot of buttons but they are all very useful and make operating it way, way easier. For example you can switch between which axis you are jogging and how much you are jogging it by all with button presses on the jog panel. It's so intuitive too... just press which axis you want to move and then it moves. So maybe what we need is a separate hand-held remote that is only for jog commands... this http://www.thingiverse.com/thing:7550
  18. Dear Marlin coders, You guys are super cool! I'm a huge fan of your firmware and how you made the code easy to read! That said here's a few things that I thought would be super awesome if they were in the firmware: 1.) Support for more buttons and encoders on the panel interface 2.) Retraction/priming, using some Gcodes to specify when it happens/ squirts back out. 3.) Volumetric extrusion (specify volume to extrude instead of mm to move the filament) 4.) Ability to adjust the speed and mm per click that jogs happen 5.) Support for a z-probe (not sure if this exists already? I haven't built one yet but I plan on it) Keep up the good work!
  19. Hairspray is an amazing solution. I'm using it for printing with abs and i've sprayed it on top of kapton tape. So far I've printed four times on the hairspray with absolutely no loss in adhesion. Usually after the third time kapton tape starts to get weaker but not with the hair spray! I am tempted to try directly on aluminum without the kapton, considering your success with glass. Nice job!
  20. Here's a picture of my hot end You can see I have a nut wedged between the nozzle assembly and the wooden plate. Here's a diagram of my setup: The reason why I left a bit of 3mm ID at the bottom is if you don't leave that, then molten plastic will travel up the PTFE tube and form a plug. You can also see I put some smaller nuts on the four mounting bolts of the hot end and that's because the actual head box has those corners cut out and that allows the wooden plate to skew when you apply a lot of pressure from the mounting bolts (which is what I did to make sure that tube is tight to the PEEK) so the nuts prevent skewing and transfer more pressure to that short section of 3mm ID tube.
  21. backlash would result in a very consistant gap between infill and perimeter. Depending on which belts are having backlash the gap should be skewed in one direction or another. Note also if your infill lines are overlapping each other/ don't have symmetrical gaps. That's another sign of backlash. Infill should look like this |||||| If yours looks like this II II II that's a sure sign of backlash Keep track of where the gap occurs. Is it near the beginning of a layer or towards the end? Sometimes my extruder would act like it needed some time to build up pressure so lines at the beginning were thinner than at the end of a layer. This is an extruder problem and I'm not quite sure yet what causes it.
  22. The two qualities of a hot end that are at odds are retraction (oozing) and speed (how fast you can push filament out). There was a post on the reprap forums (can't seem to find it now :( ) where people were using a j-shaped solid with one outline and no fill to test high speeds (on the straight section), retraction (on the dot), and slowing down (on the curly part). here is one example of a good retraction test piece http://www.thingiverse.com/thing:15087 Something also that is important for multiple heads is the ability to retract the filament to eliminate oozing while the second head is idle. So try retracting and waiting to see how much oozes out (or how long before ooze starts). Maybe you can try retracting to the "cool zone" and then starting back up? be careful though when testing speed that the machine actually is going the speed you set. For example you can set 1000mm/s but because of acceleration and minimum layer time your printer will never reach this speed.
  23. Truly I'm amazed ultimaker is charging so much for the V2, when others with even more machining done are charging less (see: arcol.hu hot end; four machined parts in all metal and theirs comes with a heater resistor and thermistor). I think the metal hot end is the way forward! Although again nobody has done any research or calculations on what is the best hot zone length and orifice length to optimize retraction at high speeds. There's been lots done on the hobbed bolt side, but nothing on the hot end. Why? It's also possible that these numbers are different for different materials. Maybe (now this may be really pie in the sky) a hot end with an adjustable hot zone would be good? Maybe you could move the location of the fan along the heater barrel to determine where the hot zone ends? This might not be needed or practical but it's what comes to mind . Could be a good setup for research purposes too... Keep up the good work, alaris2! Let us know how it goes! Meanwhile I am upgrading my bowden tube setup once again..
  24. Yes. 4mm ID PTFE tube for most of the length, short 3mm ID PTFE tube from the top of the print head into the nozzle. I screwed a bolt on the short tube and wedged between the aluminum plate and the bottom of the wooden print head, as well as two bolts on the long 4mm ID tube to attach to the feeder and the top of the head.
  25. My ultimaker is currently running perfectly WITHOUT four of the grub screws. I removed grub screws from the pulleys on the driven axle of both x and y axes. I think this allows the belt tension to be more even around the whole belt, as well as making the whole axis drive less overconstrained. That said I could send you a grub screw
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