The wire drawing machine process is a metalworking technique used to reduce the cross-section of a wire by pulling it through a series of drawing dies. This process is commonly used to produce round cross-sections, but it can also be used for other shapes such as squares. Wire drawing is an essential industrial process that is used to manufacture various commercial products, including electrical wire and cable, wire stock for fences, and rod stock for nails, screws, rivets, and springs.
The wire drawing process involves the following steps:
Wire Preparation: The wire is prepared by shrinking the beginning of it through hammering, filing, rolling, or swaging to ensure it can fit through the drawing die.
Drawing Dies: Drawing dies are typically made of tool steel, tungsten carbide, or diamond. They are placed in a steel casing, which supports the die and allows for easy die changes. The dies have different angles, including the entering angle and approach angle.
Drawing Process: The wire is pulled through the drawing dies, and as it passes through each die, its diameter decreases while its length increases. The wire may require multiple draws through successively smaller dies to reach the desired size. The area reduction in small wires is generally 15-25%, while in larger wires, it is 20-45%.
Lubrication: Lubrication is essential in the wire drawing process to maintain a good surface finish and prolong the life of the dies. Different lubrication methods can be used, including wet drawing (immersing the dies and wire in lubricants), dry drawing (passing the wire through a container of lubricant), metal coating (coating the wire with a soft metal acting as a solid lubricant), ultrasonic vibration (vibrating the dies and mandrels to reduce forces), and roller die drawing (using roller dies to convert shear friction to rolling friction).
Annealing: Intermediate annealing may be required during the wire drawing process to counter the effects of cold working and allow for further drawing. A final anneal may also be used on the finished product to maximize ductility and electrical conductivity.
