Show HN: 3D Printed Difference Engine [video](www.youtube.com)
3 pointsby ionini2 days ago2 comments
  • jacquesm2 days ago
    This is a very impressive piece of work, it must have taken a lot of trials to get it to the point where it functions so well, these mechanisms are really hard to reproduce without using a lot of metal and very high level mechanical engineering skills. Doing it in plastic helps with dimensional stability but it increases friction and compared to say brass the surface finish is much worse. I wonder how long it will last before parts will need replacing due to wear.
    • ionini2 days ago
      Thanks! It did, I have a box with hundreds of failed parts. Never worked with metal, but PLA is rigid enough for this (at least for now). The most stressed mechanism here are probably the cams and cam followers, and the ones in the video are at least a couple of months old at this point. I will update if anything wears down!
      • jacquesm2 days ago
        If I can give you one tip switch to PETG (bed: 80 degrees, print at 240), it is much more stable dimensionally than PLA, especially over longer time. I've printed a couple of tons (literal, metric tons) of stuff over the last two years and have a farm of 40 printers, if I can help you somehow let me know.
        • ionini2 days ago
          Thank you for the advice! I will look into buying some PETG in the future and doing some tests on it.
          • jacquesm2 days ago
            Good luck, and looking forward to the next installment.
  • 2 days ago
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