Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling it through one or more drawing dies. Wire drawing has many applications including wire, cable, strained structural components, springs, paper clips, spokes and stringed instruments. Although the processes are similar, drawing differs from extrusion due to the fact that in the drawing process the wire is pulled through the die rather than by pulling. Drawing is usually carried out at room temperature and is therefore classified as a cold process, but large wires can also be stretched at high temperatures to reduce the forces at play.
The wire drawing machine is made up of the main reducer gearbox, mould case, guiding wheel frame and electrical inverter control system. The drawn wire is mostly used for making nails. Also can do welding, welded wire mesh. And other construction.
Wire drawing, the making of wire, generally from a rod or bar. The wire-drawing process consists of pointing the rod, threading the pointed end through a die, and attaching the end to a drawing block. The block, made to revolve by an electric motor, pulls the lubricated rod through the die, reducing it in diameter and increasing its length. Fine wire is made by a multiple-block machine because the reduction cannot be performed in a single draft.
Lubrication in the drawing process is essential for maintaining a good surface finish and long die life. The following are different methods of lubrication:
The dies and wire or rod are completely immersed in lubricants.
The wire or rod passes through a container of lubricant which coats the surface of the wire or rod.
The wire or rod is coated with a soft metal that acts as a solid lubricant.
The dies and mandrels are vibrated, which helps to reduce forces and allow larger reductions per pass.
Roller dies are used instead of fixed dies to convert shear friction to rolling friction with a dramatic reduction in the drawing forces as reported by Lambiase. When roller dies are adopted, the drawing stages are composed of 2-4 idle rolls and the wire is pulled within the rolls clearance. This type of solution can be easily adopted also to produce flat or profiled drawn wires.
Various lubricants, such as oil, are employed. Another lubrication method is to immerse the wire in a copper(II) sulphate solution, such that a film of copper is deposited which forms a kind of lubricant. In some classes of wire, the copper is left after the final drawing to serve as a preventive of rust or to allow easy soldering.The best example of copper coated wire is in MIG wire used in welding.
In the wire drawing machine, the wire is produced for drawing. A part of the coils is used as raw material and its diameter is reduced as required.
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