Does any one have Working models

Discussion in 'Other Interest Groups' started by gagandeep, Oct 18, 2014.

  1. gagandeep
    gagandeep Member
    Edit_Model__V8_Engine_-_Shapeways.png Hi,
    I was just wondering if any has made functioning designs like working model trains or functioning engines, stuff like that. And i thought may be we could shares some of our designs and notes, as you people must know making working designs is pretty difficult.

    For example my models
     
    Last edited: Oct 18, 2014
  2. stonysmith
    stonysmith Well-Known Member Moderator
  3. gagandeep
    gagandeep Member
    Thats pretty cool man, whats the diameter of the moving rod in the youtube clip of the train.
     
  4. stonysmith
    stonysmith Well-Known Member Moderator
    0.61mm

    I really like to push the limits :)
     
  5. UniverseBecoming
    UniverseBecoming Well-Known Member
    Nice work Stony! :D

    Looking at gagandeep's V8 and Stony's locomotive made me think of something that would be really cool. Try to design a tiny locomotive printed in situ that runs on hydrogen peroxide and a catalyst. Essentially, an air engine that operates via the pressure of oxygen escaping from the hydrogen peroxide. The catalyst would simply help the oxygen release quicker. For a catalyst, one would have to look into that, but three that I know of off the top of my head are platinum, silver and manganese dioxide. One wouldn't need the high concentration grades used for rocket engines and whatnot since the power level needed would be very low, so just plain old hydrogen peroxide from the drug store would be fine.

    The challenging part would be to design valves and pistons that could be printed in situ, yet, still have good sealing characteristics when in operation. This would involve making cylinders and valves that have a printed state clearance that slides into a working state operational clearance or something like that. Difficult to design, but not impossible.

    If one could design something like this and get it to move a few tens of centimeters under it's own power and make a video of that, it would most likely go viral among train aficionados and when they learned that they could get their own to play with by placing an order on Shapeways one would make a nice chuck of cash in a short amount of time. :D
     
  6. stonysmith
    stonysmith Well-Known Member Moderator
    First, thanks. Second, please excuse me for going all geek here. For those of you who are sculptors and painters.... I'm letting my inner engineer show here....

    If only... a guy can dream, can't he?
    I've actually spent many an hour trying to work out exactly such a concept. I think that before we can print a working steamer, we will be able to print in-situ electric motors that accomplish the same effect.

    The operative word here is "tiny". At this time, the required clearance (in FUD) for moving parts is 0.05mm, but I have found that to be more like 0.1mm to keep them from sticking together. One tenth of a millimeter is an excellent tolerance gap if your piston face is 10cm or even 20cm in diameter. But, when the piston face itself is only one millimeter in diameter, then 1/10mm gap is huge.. the gas would leak around the side and most of your pushing force would be lost. Even if you had a multi-material printer that could print the rubber gasket to seal the gap, the existing printers just don't have the resolution to make "tiny" pressure cylinders yet.

    I am excited to see where this 3d print technology is going to go over the next years. I can easily envision a future where we can print working model trains in-situ. I just need for the print technology to catch up. I think that before we get high enough resolution to print gaskets, we will be able to mix plastic with metal, and thereby make working electric motors. An electric motor can be rather simple.. it can have some pretty big gaps. We just have to be able to mix materials.

    There's nothing I'd love more than to pay homage to those guys who designed these massive "big iron" steamers over 100 years ago.. with a working model 25mm long <GRIN>
     
  7. MrNib
    MrNib Well-Known Member
    A turbine engine may be more feasible than a piston engine using expanding gasses. Perhaps even dry ice would power such an engine for a minute or two as it sublimates. You might need some gear reduction to get any useful power transfer but that's also an option with 3D printing.

     
  8. UniverseBecoming
    UniverseBecoming Well-Known Member
    I dream the same kinds of dreams! I'll bet we'll be doing that within 3 years. I can hardly wait! :D

    Yeah, there would either need to be something like a lever that one actuates to move everything from the as printed clearance to the operational clearance or there would need to be devised a very clever way of doing the same without prior intervention.

    As for a turbine, yes this would be easier to do because the clearance problem is reduced. There would sill need to be valves to control the gas pressure though. The gears would probably work in the as printed clearance without jamming if designed right.

    Dry ice would work well I think since it wouldn't need to run for very long so the accumulation of ice from atmospheric humidity wouldn't factor in. One thing though is there would need to be a lot more flow of gas when compared to a piston engine. With a piston engine the gas can have a few milliseconds to build up pressure before being released into the cylinder, so the flow could be quite a bit less.

    Then again, two turbines could be used. along with two pressure tanks. A tank would build pressure and then release into a turbine while the other tank built up pressure and so on.

    Speaking of carbon dioxide. Another chemical reaction that could be easily implemented is sodium bicarbonate and a mild acid like vinegar.
     
  9. stop4stuff
    stop4stuff Well-Known Member
    Yes, however the 3D print technology for the working engine I have designed isn't quite there yet, on paper my design of a LTD heat difference engine is entirely feasible and more efficient than a Stirling engine with the same temperature difference.

    A device that may be perfect for printing is a reciprocating rack & pinion

    Paul

     
    Last edited: Nov 1, 2014
  10. bvr
    bvr Member
  11. Sparkshot
    Sparkshot Well-Known Member
    Hmm, well, I can't claim to have made moving hinged and working parts yet but I have been 3D printing locomotives, chassis and rods, brought the motor and gearbox etc and got them working. My range is mostly locomotive kits but to print one where it just moves from the off seems way out there. Maybe one day.

    Maybe if something can be 3D printed and then transferred to a different printer mid print and somehow located on the new bed exactly, then loads of different materials could be done.

    Maybe a new 3D printer that is a hybrid of all the different technologies with about 10 different heads is the answer!
     
  12. kaadesign
    kaadesign Well-Known Member
    Anyway... enjoy the engines!...

    [​IMG]
     
  13. mkroeker
    mkroeker Well-Known Member
    Anyway that thread is several years old