Quote:
Originally posted by Since87
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It might be difficult to get a precise fit between these features. When designing molds you have to take into account how the material will shrink when it cools. However, the machining of the copper could be modified after a sample molded piece was produced, to ensure that the alignment was good.
It's often easier to mold a piece, and make the rest of the design work around the molded piece, than it is to get the molded piece to match precise dimensions.
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The precise shrinkage factor is probably well-known, and can be accounted for in the design of the mold. For prototype parts molded for the automotive industry, a positional tolerance of <.25mm (.010") is commonly maintained. I don't think (but I don't know) that such a small deviation will affect matters greatly. Only cathar knows for sure.
Also, a couple of round "knobs" might be all that is needed for locating the pieces together. They can be made assymetrical to ensure proper fit (see pic).
Bob