, the size becomes smaller and even the shape changes. When drawing soft metals (such as gold and silver), a steel mold is sufficient, and the steel mold can have multiple holes with different diameters. The drawn steel wire (steel wire) generally uses a cemented carbide die (Tungsten carbide nib). The typical structure of this die is a cylindrical (or slightly tapered) cemented carbide core that is tightly embedded in a circular steel sleeve. In (case), there are bell radius, entrance cone, approach angle, bearing and back relief in the inner hole of the mold core. For drawing non-ferrous metal wires, such as copper and aluminum, wire drawing dies similar to steel wire molds are often used, with some differences in the shape of the inner hole. For thinning wires, polycrystalline molds (man-made diamonds) can be used, and natural diamond drawing dies are also used.
　　 Some soldiers in the Terracotta Warriors and Horses of Qin Shihuang can see metal wires on their stone armors, so it is estimated that some people have mastered the drawing technology at that time. In Tiangong Kaiwu's book of the Ming Dynasty, we can see the craftsmanship of needle making, among which is the use of drawing dies.