MIT: 3-D printing with variable densities

By variable densities this video is referring to the density of the infill, not the density of the material extruded. At least that was my take on it.

Hasn’t the DIY 3D printing scene been doing this for quite some time now with the use of spars internal structures for solid objects?

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About Richard

I am a PhD candidate in Materials Engineering located in Melbourne, Australia.
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5 Responses to MIT: 3-D printing with variable densities

  1. ann says:

    Not exactly.

    The example with plastic is the same principal as reprap where the infill pattern can be adjusted for a specific density. But the concrete example show that the material is self can be changed: on the outside is full concrete on the inside is concrete foam.

    This is interesting as up to now we had multimaterial where each unit of volume must have the properties of one of the feed materials but here is an example where we can variate the properties of the material continuously in certain range.

    One thing that would be interesting for reprap is to be able to change the elasticity of the material continuously, This would be great to embed springs into a design without a hard frontier between two materials that breaks easily.

    • Richard says:

      Oh, I see. Thanks for clearing that up.

      Altering the properties of plastic as its extruded would indeed provide for some interesting objects to be printed. I suppose this could be achieved by feeding two different plastics, with different mechanical properties, into the print head at different rates to control the properties of the product extruded. Or alternatively a more crude alternative could be to expose select areas to high intensity UV light during the printing process, making those areas more brittle while leaving others flexible.

  2. olderdog says:

    They’re working on the feeding-multiple-plastics-into-a-mixing-chamber thing at MIT too. Just at initial stages. But the other thing is that it would be nice to be able to do some of this in analog form, i.e. you extrude a fairly coarse thing that has different skin/internal properties rather than having to make a zillion passes, each with a slightly different density or stiffness or whatever.

  3. Rich Beck says:

    Lady in the video says 3D printing was invented at MIT…not quite. The term was coined there by the grad students who went on to form Z Print. It looks like a very early patent was in 1979, http://www.google.com/patents?id=TfY0AAAAEBAJ&zoom=4&pg=PA1#v=onepage&q&f=false, though this product was not commercialized. If you look at the patent drawings, it has all the ingredients of modern extrusion printers. Also prior to the MIT work, a professor at UT invented SLS (Selective Laser Sintering) used widely for 3D printing of metal and other hard to melt materials. see: http://www.google.com/patents?id=nCMsAAAAEBAJ&zoom=4&pg=PA1#v=onepage&q&f=false, this was filed in 1986, nine years before the MIT grad students did their work.

  4. Pingback: 3D Printing in the High School Classroom | James Madison University 3-SPACE

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