1. Try to use high-quality carbide drawing dies produced by advanced mold processing technology, or diamond drawing dies
At present, the grinding process of wire drawing dies abroad generally adopts high-speed mechanical grinding machines and metal grinding needles coated with cemented carbide. The equipment runs smoothly, and the specifications and use of grinding needles are standardized to make the product more accurate. The hole size of the mold is detected by a profile recorder and aperture measuring instrument, and the surface finish is checked with a microscope dedicated to the inspection wire drawing mold. Many domestic manufacturers still use backward equipment and use manual operations to grind the hole pattern. Therefore, there are the following problems: the parameter of the hole pattern fluctuates greatly, and it is difficult to process a straight working cone; the intersection of the sizing area and the working area It is easy to grind out the transition angle, which causes the secondary compression of the wire in the sizing area, increases the external friction, shortens the length of the sizing area, and shortens the service life of the mold; the frequency of repair of worn grinding needles varies from person to person. Non-standard, resulting in poor consistency of the hole pattern. The detection methods are also backward. They can only rely on visual inspection or simple tools such as a magnifying glass and a microscope.
2.Choose a drawing die with a good hole design
The drawing die hole type is generally divided into a curve type and a straight type. From the perspective of the uniform deformation of the wire in the drawing die, it seems that the curve type is better than the straight type. The hole structure can be divided into five parts: "entrance", "lubrication area", "reduction zone", "bearing" and "exit " according to the nature of work.
3. The wire used for drawing must be pretreated
(1) Surface pretreatment: For the wire with dirty surface and more impurities, it must be washed and dried before being drawn; for the wire with more oxide on the surface, it must be finely acidified and baked. Then draw after drying; for the wire with peeling, pits, heavy skin and other phenomena on the surface, it must be polished by a polishing machine before drawing;
(2) Heat treatment: For wires with excessive hardness or uneven hardness, the hardness should be reduced by annealing or tempering, and the wire should maintain good hardness uniformity before drawing.
