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Thread: Thoughts on 3d sand printing...

  1. #21
    Quote Originally Posted by DavidF View Post
    Thats where it would get more expensive and software could be troublesome for me...
    You might read up on a guy called Joseph Prusa as far as a business model and having less experience in software. He was a guy back in 2010 just messing around with DIY FDM printers, specifically the RepRap. He ended up creating his own version called the Mendel Prusa and released it open source, the community did a ton of improvements throughout the years. Well during this time he was in college so he just quit and started selling his kits as well as releasing all his designs as creative commons. Today he owns http://www.prusa3d.com/ and selling complete printers 1K a pop assembled and kits at $600-800, he's so back logged I ordered a printer back in feb and it won't be here till may. His R&D was a lot of him tinkering and the community doing improvements here and there.

  2. #22
    Moderator DavidF's Avatar
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    Quote Originally Posted by dzuari View Post
    You might read up on a guy called Joseph Prusa as far as a business model and having less experience in software. He was a guy back in 2010 just messing around with DIY FDM printers, specifically the RepRap. He ended up creating his own version called the Mendel Prusa and released it open source, the community did a ton of improvements throughout the years. Well during this time he was in college so he just quit and started selling his kits as well as releasing all his designs as creative commons. Today he owns http://www.prusa3d.com/ and selling complete printers 1K a pop assembled and kits at $600-800, he's so back logged I ordered a printer back in feb and it won't be here till may. His R&D was a lot of him tinkering and the community doing improvements here and there.
    Not looking to go into business selling these, just want one for my own work. as long as I can stay with my current plan I wont have any trouble, all the hard work has been done for me. If I have to step into something that uses a galv, then I will have to take a different approach to controlling it. Fortunately there is inexpensive laser cutters that could be adapted for use and I could probably hack their software to do it. That is a bridge ill cross when I come to it.
    Right now I just want to work on the sand feeding layering system. One of the main reasons I like what the ex1 is doing is that it feeds the sand from a hopper on top of the sweeper rather than push t up from a vat under the build table. That keeps a driver open on the mks board that I will use for the sweep cycle between layer changes (e2), e1 will be used to trigger the laser and one of the fans could be used to actuate the auger on the sand feeder. Sounds easy right? LOL

    - - - Updated - - -

    sintered sand from the Sand made 3d printer
    sand print.jpg
    A calm sea does not make a skilled sailor...
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  3. #23
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    The heat activated Croning process sand binder activated with a laser can not be terribly difficult. The binder is available from casting suppliers...
    http://www.achem.de/auswahltabellee.htm

    Broken down;
    The dropping floor sand box could a simple Z axis with multiple spindles synced with a belt drive. It is always loaded in the same direction, so backlash is irrelevant. This could be done with simple AMCE or trapazoid spindles and nylon nuts.

    The sand distributor needs single axis motion control, and the special sauce to get the sand layer even, as discussed above. I wonder how much magic is in those commercial units. If could be that the secret is very pure homogenous sand, and then the hoper just moves across about xx sand diameters above the last layer, and it just works.

    I am guessing that the EOS commercial unit is not moving the laser head around on an X-Y axis, it is too fast for that. I would guess that they are just directing the laser beam with a miror on a two axis gymbol. Not sure how hard that would be to acheive, but it can be broken down to a the mechanical mirror drives, and the algorythm for the joints to be programmed into LinuxCNC's HAL. The complexity of this could be traded against print time, and a simple X-Y motion control using linear rails and belt drives to position a down facing laser implemented.

    The slicer software is easy, as you are just doing the same thing as a 3D printer. You just need to invert your models to print the outside. I have built a 3D printer and CNC lathe. The 3D Sandform printer should be similarly acheivable for a hobbiest.
    Mark

  4. #24
    Quote Originally Posted by rotarysmp View Post
    The complexity of this could be traded against print time, and a simple X-Y motion control using linear rails and belt drives to position a down facing laser implemented.
    Mark
    The added material and motors for the xy would increase the base price and more variables of fault and breakdown. A simpler system math wise would be a Z trapezoid spindle table, an X only gantry and an A axis head that rotates as the X moves. So a 2+1 axis machine technically. Since the laser is always hitting the sand at a set height calibrating the system wouldn't be hard to do. The only math you'd have to figure out is Y offset / per degree rotation of the A axis laser, then just compute the compensation in the firmware. Less hardware, little bit more math but you'd see a drastic increase in print time and it'd wear out less.

  5. #25
    Moderator DavidF's Avatar
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    Been running my printers for several years, had a few clogged nozzles but never any break downs or wear out. Cost? I bought my FT-5 for $500.00 it has dual z motors, dual y motors, and runs on linear rails.
    This is the platform I will be using for testing once I sort things out a bit. K.I.S.S. pretty easy to swap the extruder drive for the laser
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  6. #26
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    second option is using the v slot linear rail from open builds. Ive collected all the stuff i need to build another fdm printer just havent put it together yet... Still working on getting my second cnc mill up and running.

    A calm sea does not make a skilled sailor...
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  7. #27
    David,

    If you look it seems if the Sandman unit had a hopper of sand and a screed bar. I agree that the bin on the side and a small hopper that moves makes for a smaller unit. The Hopper that moves needs only hold enough sand for 2 layers or so, as it can be filled from the bin every 2nd layer. This would save on weight moving across the unit. I'm wondering if you can get enough spreading action by attaching a phone vibrating unit (small motor with an offset weight... like $2-$5 surplus) to the leading edge of your spreading bin. or mount a small floating bar(over sized screw holes, with maybe a small set of springs to return it to center) on to the front edge and attach the vibe to that ....or just make the blade oscillate with a small crank shaft and motor. Doesn't need to be a stepper just something to move the sand. I think you maybe on to something with the FT-5 as a base. (great all I need is another project to be rolling around in my head :lol: )

  8. #28
    Moderator DavidF's Avatar
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    Think i might have it figured out, its like a walking foot on a sewing machine......pretty clever! The "toe" of the walking foot when in its forward position seals off the hopper, and its motion not only dispenses the sand, but tamps it down lightly as well.
    Now i just need to figure out how to duplicate it. Time to grab my crayons....
    A calm sea does not make a skilled sailor...
    http://thehomefoundry.org

  9. #29
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    Could this idea work??? printing with Sodium Silicate sand into a rich CO2 atmosphere.??

  10. #30
    Quote Originally Posted by hamilton View Post
    Could this idea work??? printing with Sodium Silicate sand into a rich CO2 atmosphere.??
    i think you'd have major trouble keeping the silicate from hardening in whatever feed mechanism you're attempting to use.

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