The main things to think about when choosing a machine are usually speed, costs, and color. Printers that work directly with metals are generally expensive. However less expensive printers can be used to make a mold, which is then used to make metal parts.Typical layers are around 100 μm thick, or about one tenth the thickness of a human hair. Prints can take anywhere from less than an hour to many days, depending on how complicated and big it is.