Help Needed Finding Right Metal For Project

Discussion in 'Other Interest Groups' started by Xander3D, Jul 9, 2018.

  1. Xander3D
    Xander3D Member
    Hello. I am working on a a project that combines plastic and metal components. It is a detailed spinning top made with plastic with metal towards the outside to give it centrifugal force while spinning.

    My only problem is that after printing it, I found that the parts didn't fit, despite fitting in my 3D model. I was using polished bronze steel and processed versatile plastic. It sees that the metal was coated with something causing the outer edges to be too big, and the holes in it to be too small.

    For my next printing, what metal material would you recommend for the metal segment? It needs to be durable and hopefully heavy. Would aluminum work? Is there anything heavier than aluminum that would work? Thank you!
  2. JoyComplex
    JoyComplex Active Member
    The problem is steel. The way the steel is produced causes it to shrink in unpredictable ways - unless you order direct from ExOne. Check out the steel guidelines.

    The bronze infiltration of each steel part makes this material less dimensionally accurate than other Shapeways materials. Shrinkage is more prevalent, especially on small holes and inner diameters. Accuracy and tolerance can vary greatly depending on the model, and are hard to predict because they are so geometry specific.
    A 5% deviation on a ring is around 1 US ring size. So if you order a size 6, the deviation could cause the actual print to be a size 5 or 7.
    Aluminum might work but it's pretty light and more than steel. Raw brass might work. Again, it'll cost more. If it's a one-ff thing than it might be worth it. If you were going to make a bunch of your design, you might try to make your model bigger to try to compensate for the shrinkage of the steel. But, you'll never get a perfect fit.