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aaronalai

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Posts posted by aaronalai

  1. Lol, we might have a winner! Well at least we may be on the right track :smile:. So in the screen shot I posted before, it looks like the bowden tube is suppose to fit concentrically within the top portion of the white teflon piece; I understand the screenshot is for the V2 hotend for the UM1, I think it stands to reason yours should fit inside there as well. Is there a way to mark the bowen tube to see how far it is going below the aluminum plate? This could help aid in confirming the bowden tube is seated in the inner-inner diameter of the white teflon piece.

     

  2. I was wondering if there were any cad models of the UM2 out there? I'm still waiting for mine, but in the mean time I want to design some things for it, and it would be nice to have a somewhat dimensonalized model of the thing; even if I had the UM2 in hand, it would still be nice to have a 3D model of it for clipping things to it and such. I'm not talking a full model or anything, maybe just something with a really generic frame or 2d drawings of the frame.

     

  3. @gr5 & @braddock

    Have either of you pulled the filament out of the extruder when it was 90C and let it cool without touching it? Is the exterior smooth (aside from feeder knurling) or does it have a texture to it or a ring? I was watching some of the Ultimaker Q&A presentations about the hot end V2 by Martijn, and after seeing your two comments it may be that there is some abrasion inside the section of the white teflon section the bowden tube mates with.

    eArxXvx.png

    If there is an abrasion in this suppose to be cylindrical walled section of the head then it seems to reason that if a bit of material is retracted it could cool up there and get snagged in the abrasion with the snag being hardened plastic in the shape of the abrasion. It may not be an abrasion either, but a small deformation at either end of the bowen/printing head interface. This could also explain why others can do so many retractions with out any problems while only some have problems, gr5's abrasion may be shaped differently so it only snags the tip of the filament while it's being fed through the bowden tube.

    @gale posted this image in this thread:

    Filament_stucked_annotated2.jpg

    http://umforum.ultimaker.com/index.php?/topic/649-very-high-friction-in-the-bowden-tube/?p=5039

    If there is significant knurling on the filament this may negatively interact with an abrasion inside the white teflon piece and attenuate movement of the filament through the hot end, and cause moments of under extrusion.

    I understand the low friction coefficient of teflon and such, but if there is a physical abrasion as a function of a cut or chunk in the material this may be enough to distort the inside diameter of the hot end to cause all types of problems.

     

  4. Thanks for the suggestion, after some internet searching it looks like 50-60C is about as high in temp as a stepper should go, and that might be pushing it. I like a good challenge and am interested to see what I come up with. The reason I was thinking of heating the chamber independent of the heating bed was to get the part to be a uniform temp, but I suppose a temp difference of 20C at 40C ambient chamber temp is more effective than a difference of 40C at 20C ambient chamber temp, and probably helps enough.

    I was wondering if there were any reports of heated build chambers clogging nozzles more frequently as a function of keeping a lot of filament much hotter than ambient temperature before entering the heated portion of the hot end?

     

  5. Yes, that's why I came to that conclusion.

    Having the whole piece at nearly the same temperature during the print really helps.

    No heated bed: uniform temp but considerable overall shrinking, low adhesion and high lift-off forces to fight with

    Heated bed: good adhesion but high temperature gradient within the part and partial shrinking causing the elephant foot

    Heated chamber: good adhesion and uniform temp, very low lift-off forces due to shrinking until the part cools down

     

    Does the nozzle of your heated build chamber clog more frequently, or is the idea of a mineral oil cooling system not necessary?

     

  6. I've been thinking about this a lot, and have seen posts about others trying to implement it in commercial versions, but from what I understand Stratus has the patent on it or something to that nature. I don't have a physical version of the UM2 yet (still in Ready status), but I've been looking at a lot of photos of the machine at as high resolution as I can find, and I think you could get away with sealing up the front with plastic sheet, putting a pyramid trash bag shaped thing on the top to allow the head to move, and some nichrome wire to generate the heat.

    Then you run into the problem of how do you keep the crucial temperature differential in the printing head between the melting volume and the sold volume of the filament; I think you can replace the heat sink with a mineral oil heat sink system, and and off-board pump and cooling system for the oil; you would have greater control of the temperature over which the area the heat sink makes contact with the print head structure, because you could alter the temperature of the mineral oil before it enters the heat sink structure. The added mass of the oil and more solid heat sink structure, could be offset by the removal of the 3rd center fan. I am very excited to get my UM2 and have been daydreaming about ideas for it and for prints, even if the aforementioned idea seems convoluted and unnecessary I'm still going to see how I can make this printer as accurate as possible without changing it's fundamental operating system.

     

  7. Anyway, I experience this forum as the most friendly. I've met many forums, but none like this. It is now an integral part of my life ...

     

    Yeah me too! I used to spend this time on Reddit or something; I am very glad this forum exists. I had a list of pros and cons for several of the major printing manufactures, and one of the top reasons I picked the Ultimaker group is because of the open source mentality and the activity/tact of the forum.

     

  8. Wow those are fantastic models, every one of them is so professional looking! I love this forum I get to meet so many interesting people!

    Ian, you should print out your model for a human vs printer comparison :smile:. Also great idea for a thread, I know there was recently a sticky added, but I think this should also be a sticky; very inspirational.

    Good time to add the thread, this weekend I'll rummage through my electronic circuit builds and post some of my favorites. Many of which are going to be brought back to the work bench to mate with printed parts, increasing the utility of what I have already made significantly.

     

  9. I also love the idea behind it, but, I haven't been able to work out how to reorientate my model to the build platform yet. Any help would be appreciated. Thanks

     

    Edit>Transform then you can grab the little colored bits in the center to rotate and translate

    I like the align feature also under edit, where you mate either the LastPlane or AABox? along an axis for a flatter alignment. The image of the grid on which the object floats is a bit misleading, I thought the object had to be in contact with it for the supports to be properly generated, but they don't so don't get discouraged if your model is floating a couple inches above the white matrix.

     

  10. I agree, I understand it's a lot of time and energy wasted so the person printing it probably doesn't find it very amusing, but many of the failed prints look funny :smile: Yeah I'm glad to see they are taking such interest in improving their software. I have a list of bugs? to share with them in their forum or email and in this thread later today when I get some free time. I am more than happy to help!

     

  11. You print at such a fine resolution, have you tried the acetone vapor technique to get a polished exterior without sanding? I've seen a few videos online, and if you have your setup right the results look great! There can be a small amount of fine detail lost if you leave a piece in too long, but that tongue guy looks like a really good candidate for the technique.

     

  12. OK, that wasn't good...

    I installed the new firmware. Aborting a print causes the machine to have a heart attack. The first time, it just rebooted. The second time the LCD display went blank. I've done a re-flash just in case but don't have time for more testing today.

    Additionally, the filament drive motor was making a crackling/buzzing noise for awhile and when I went back to my print the noise was gone but I was wildly under-extruding.

     

    Daid uploaded the wrong firmware this morning, try re-downloading it.

    http://umforum.ultimaker.com/index.php?/topic/4033-cura-1401-printer-restart-after-aborted-print/?p=32212

     

  13. Looks great! I saw a video of someone sanding one of their models, yeah it looks like it takes forever, but your end result looks really nice. I was looking at some of your other photos, and truck looks really good also, it looks better than a model you would buy at a store.

     

  14. @ AaronAlai

    Let me know if you have found a cover.

    Markus

     

    Definitely! I had a project a couple years ago using large pieces of very clear plastic sheets about 1/4 inch thick. I mistakenly ordered twice as much as I needed and the company wouldn't let me return the product. I found them last night and they are perfect for making an entire cover for the printer, I looked at the full dimensions in the user manual. I already have a design drawn up and am going to actually do the cutting and assembly when the printer arrives so I can make sure to include extra filament spools.

     

  15. I've been wanting something like this as well. Currently I am using the checker pattern on the simulated build platform to estimate the size of of the object. If I need to make more fine measurements I try to load the stl file into SolidWorks and make measurements there, but even in SW I have limited interaction capabilities with imported stl files and have to make adjustments to the model to make any measurements.

    This is like extra icing on a very delicious cake though, I understand there are a number of minor bugs that need to get squashed in the firmware. Perhaps something extra for the future, when you can breath a sigh of relief that the firmware/software side of things is running like a well oiled machine. Not that things are not going well already :smile:

     

  16. I wouldn't say that the motors aren't strong enough... just that when good quality prints depend on very precisely controlling the movement of the filament into the printer, and there is no feedback loop to ensure that the requested amount was actually delivered, anything that you can do to make the system more predictable is a good thing.

     

    I have been seriously thinking about this a lot! Is something like a laser emitter receiver sensor not used in a feed back loop for a reason? Is it because the spool moves too slowly and the sensor drifts? Have you run across anyone ever trying to implement this feature?

     

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