You could do this a variety of ways. Ball mill would work fine. If you were doing this in "real" volume, you would likely likely just cast aluminum into this s

You could do this a variety of ways. Ball mill would work fine. If you were doing this in "real" volume, you would likely likely just cast aluminum into this shape. However, companies like apple/amazon/etc have a tendency to just find a supplier who can sell them semi-specialized machines and buy a lot of them. Apple has bought out (either the machines or capacity) for things like laser drilling. Amazon echo/echo show's were made by buying a ton of semi-custom machines from these folks: https://mdaprecision.com/ https://mdaprecision.com/ (They talk about it in various places)