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Heated build chamber

Discussion in 'Mods and Upgrades' started by BjG, Feb 23, 2013.

  1. BjG

    BjG Member

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  2. SPyKER

    SPyKER Active Member

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    On all those the print bed stays within the framework. On the Robo 3D, the bed appears to be able to move slightly outside the framework. When one creates a framework, it's going to have to come away from the front and back on the printer, and stay more than 8 inches higher then the printing platform to allow for possible produce height.

    For the cheapos out there (like me), I could see a large clear storage tub, turned upside down, and "H" cut so that the two flaps could rest on the front and back towards the apex. With a hot air gun, they might even be formed to fit the formed sides nearly perfectly. Well, at least for a first attempt at fume and temperature control.
     
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  3. JDM_

    JDM_ New Member

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    This is the only downside to having a moving bed like RoBo has. It makes it a bit more challenging to encase it to control the build areas temperature. I like your storage container idea SPyKER. I am going to have to come up with a way of keeping heat in when I decide to print large ABS objects.

    I would like to see what ideas others can come up with. Maybe there is good/easy way we can come up with that still looks somewhat decent. I'm not sure how hot the build area needs stay to prevent warping but I will be printing in my garage in Florida which gets pretty hot in the summer.
     
  4. tesseract

    tesseract Moderator
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    This video gave some good pointers on things to do as well He showed major improvement over the first attempts and the last one looked perfect Here is the link

     
  5. Seshan

    Seshan Active Member

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    I looked at lowes Canada today, and they had 30''x 60'' and 1/8th thick plexiglass sheets for about $45 which isn't bad, I also looked at tubs and they will be about $20 each and I think I would end up needing 2 So I think it would be better to go with the plexi glass, it will look nicer and be more customization. and the price difference isn't that bad, you can probably get it even cheaper in the US, since all the stuff here is imported from the US anyways. D: It hard to tell what I will need so we don't really have any details on the printers. :(
     
  6. Drathus

    Drathus Guest

    Plexi is what I'm planning on using.

    Start with 3D printing some edge and corner clips to hold the sheets together, and go from there. Can't do too much planning on it (sadly) until the printer gets here and I work out where it's home will be and how much space I'll have around it to work with.
     
  7. Printed Solid

    Printed Solid Volunteer Admin
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    When I first got my bot, pretty much everything made of ABS failed. After adding an enclosure, leveling enhancement, and adhesion promoter (hair spray:D only necessary for larger prints) everything works great for me. You definitely need an enclosure to keep the heat in and keep out any drafts if you're building with ABS.

    I have my bot sitting on a nice sturdy antique elementary school desk that fits its footprint pretty closely. I decided to build a framework around the entire thing. My original concept was that it would be airtight to keep the heat and fumes in throughout the build with a door on the top leading to a fume hood that can vent everything out when the build is done. I've kind of built it in pieces, so I strayed from the original concept.

    Primary materials of construction are stuff left over from other projects. 2X4 frame with panels made of foil lined foam board insulation material. One wall is made of that bubble wrap foil lined insulation material so I can flip it up as a door and move the frame off of this bot and on to another. The front is a 'duct tape hinged' piece of foil lined foam board with a window cut out an a piece of acrylic glued on as a window. The top is foam board as well and has a hole cut out. While it is running, I place another piece of foam board over the hole. I typically leave it open a crack when I run overnight because it seems to get really warm in there and I don't want to overdo it. I have a HEPA filter with activated carbon to keep the fumes down sitting next to the opening at the top. It works really well. I can post pictures if anybody is interested.

    I'll also note that while I was building the frame, I just left two pieces of the insulated board sitting on either side of the bot and draped the foil lined bubble wrap over them. This worked pretty well

    It is pretty ugly, but it works.
     
  8. Seshan

    Seshan Active Member

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    I'd be interested in seeing some pictures :D
     
  9. Printed Solid

    Printed Solid Volunteer Admin
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    Again, ugly, but it works.
    2013-03-03 19.09.13.jpg
     

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  10. Michael DiFilippo

    Michael DiFilippo Active Member

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    its a shame, they made RoBo really sleek and made it look like something you'd want "desktop" but the reality of wanting/needing a chamber is becoming more real.
     
  11. Printed Solid

    Printed Solid Volunteer Admin
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    I can't speak for anything other than ABS or PLA. Some type of enclosure is a must for ABS, but you definitely do not need or necessarily even want, a chamber for PLA.
     
  12. Michael DiFilippo

    Michael DiFilippo Active Member

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    yeah I was speaking in regards to printing ABS.
     
  13. James

    James Member

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    Quick Question....What is the frame/Bones of the machine made of? I mean what does the stepper motors, smooth rods connect to. I seem to recall that the robo is made with injected molded plastic? I mean that from the pictures I saw in the updates on Kickstarter it looks like the base is made of plastic. Wouldn't having an "enclosed to keep the heat " case cause some issues with warping the frame and printed parts used in the robo ( gears , mounts ...).

    Please Please correct me ROBO Team
     
  14. Printed Solid

    Printed Solid Volunteer Admin
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    That's a good point James. My printer has quite a few plastic parts. The plastic arms that attach the HBP to the z-axis do warp terribly at temperature. Its not a big issue when you get used to it, but I do have to relevel after heating.
     
  15. Harry

    Harry Team ROBO 3D
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    I'll point this to the Robo Team
     
  16. JDM_

    JDM_ New Member

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    I guess the key is to be able to control the temp inside the chamber. If you can keep the temp on the inside so it's warm enough to prevent ABS issues but not hot enough to cause warping on the printer.

    I'm thinking it is possible to have a vent or fan that is tempeture controlled. So once the inside reaches a certain temp it will automatically vent of some warm air out.

    I wonder if RoBo's Arduino Mega board will have an extra input/output that could be used to control a chambers temp?
     
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  17. tesseract

    tesseract Moderator
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    OK guys here are some alternatives and they are really cheap and easy to try I just saw them so I thought I would pass the info along. To anyone who has a 3dprinter already PLEASE gives this a try and let us know your results but this info is new to this forum I believe.

    Solution 1: ABS slurry--- Soak some pieces of ABS directly in acetone until fully dissolved Solution should be very watery in consistancy and is applied sparingly. To apply use a Qtip and simply swirl the solution in the area your print will be it does not mater if the coverage is complete in fact small random gaps actually help. Some people were apply through a screen of sorts to make sure the coverage had small gaps. It is usually applied when the bed is cool. The success rate of NOT have parts lift at all is VERY VERY high. In many cases the reverse is now true the parts tend to not to want to come off the base after they are finished.
    It tends to last for 5-6 printings and does not have to be removed simply replaced.

    Note: PLA seems to stick to the ABS slurry as well though from what I have read lifting is not as big of a problem with PLA. Many people responded to this with success stories and it easy to do a cheap to try.


    Solution 2: PVA glue solution---just get some PVA glue water it down to a milky type solution. Brush onto the heated bed it will dry in around 30 secs (with the bed on) print and nothing will lift. then leave to cool and it will crack off easy.
    To remove PVA just use some glass cleaner and will wipe clean.

    Note did not see much response to this Solution but it may work just as well and is easy to try and also not that expensive.
     
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  18. tesseract

    tesseract Moderator
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    Some information as to why lifting may be occurring in the first place. Not my experiences just passing the information along.

    Just because healing/cooling has a definite cause-and-effect on the warping does not mean that it is the ultimate source of the frustration. All of these solutions are simply masking the root cause!

    To prove it, try printing a circle (or a gear) without any filling (just a thin circumference). I can guarantee there will be ZERO warping if the nozzle builds up the Z thickness by traveling around the perimeter, versus filling up a bed of plastic with rows/columns (or a honeycomb).

    What happens is that the nozzle goes back and forth, squeezing out plastic the entire time. When the nozzle returns, it yanks back the plastic which was recently laid. It is just gooey enough to allow a bias, pulling the freshly secreted plastic in the last direction that the nozzle traveled.

    If the nozzle goes back and forth, why doesn’t the yanking cancel out? Because when the nozzle returns it yanks back BOTH strokes. The “coming stroke” is yanked back less than the “leaving stroke” (due to cooling and other factors), but a bias exists nonetheless. The bias creates a tension towards the center.

    To exacerbate the “warping effect”
    ---------------------------------
    * Let cool air come in through the windows of your 3dprinter. By cooling the plastic off quicker, the freshly laid plastic is less “moldable”. Hot and gooey plastic will not contain any tension as it finally cools.

    * Put less space between the nozzle and the build plate when calibrating. With the nozzle closer to the freshly laid plastic, it digs in deeper and yanks back more plastic. Part of the reason that the warping is so bad is that once curling starts, it puts less space between the bed and the nozzle. That in turn causes more curling in a sort-of feedback loop.

    * Print faster. The reason why “print slower” is on the list of solutions is that it gives the freshly laid plastic some time to solidify, resisting the “yanking effect”. This is in contradiction with letting “cool air” come in. That is why neither tips offer a great solution! There is a balance between cooling sufficiently to completely solidify (impervious to yanking) versus cooling enough to allow yanking (with tension).

    * Print with old dirty Kapton tape. The reason why the “acetone / ABS slurry trick” helps is because it anchors the bottom layer. With a sticky first layer, it is able to combat the tension a little better. Again, this is just a method to fight the symptoms without eliminating the cause.

    Bad Side Effects
    -------------------------
    The number one way to clog your nozzle is to let it get too close to the bed (or the last layer printed). The stepper’s teeth strip out the plastic filament when the nozzle is “blocked off”. So, if your model starts warping, it often has the unwanted side effect of digging a pit into the filament which will ruin the print and then require maintenance on the machine.

    Possible Solution
    -----------------------------------
    Modify G-Code so that the extruder lays down plastic in one direction. When the nozzle returns it is necessary to lower the Z-axis a tiny bit so that it will safely clear the return path. Unfortunately this adds to the build time. It is just one solution, so hopefully someone out there will think of a better method now that the source of the problem has been identified.
     
  19. Printed Solid

    Printed Solid Volunteer Admin
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    Jeff, I read both of those posts on different forums. Was that you or is this a repost?

    My experiences:
    ABS slurry works REALLY well. Good luck getting your part off of the HBP when you use it. I generally avoid it for this reason.
    AquaNet hairspray is another good one and I use it all the time. Seriously. just make sure to mask off your mechanical parts so you don't gum things up.
    A really flat build plate, with polyimide (kapton trade name), cleaned with acetone, and leveled works well for me at 110C. AquaNet takes away a little bit of the need to mess with leveling.

    On the 'root cause' post. I agree with some points, but don't think that absolutely nails it. I'm guessing true root cause has to do with materials properties of the ABS otherwise you'd be seeing the same types of issues with ABS, which you typically don't.
    There are also some parts that are not correct. I've found that my parts stick extremely well and I do not get any nozzle clogging if I 'print' my first layer with the nozzle nearly contacting the HBP. The explanation he gave is logical, but it just doesn't match my experience. I try to avoid doing that because its going to be hard to peel the print off the plate and I usually end up tearing my tape. Its also probably not great for the nozzle.
     
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  20. Michael DiFilippo

    Michael DiFilippo Active Member

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    so ABS is known for warpage, PLA not so much, what about nylon?
     

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