What are the common types of wire drawing dies?

Flat wire molds usually refer to various molds for drawing metal wires, as well as flat wire molds for drawing optical fibers. All flat wire molds have corresponding shaped holes in the center, such as circles, squares, octagons, or other special shapes. When the metal is pulled through the mold hole, its size decreases and even its shape changes. When pulling soft metal (such as gold and silver), a steel mold is sufficient, and there can be multiple holes with different apertures on the steel mold. Flat wire molds are widely used, such as in electronic devices, radars, televisions, instruments, etc. The precision of wire materials used, as well as commonly used tungsten wire, molybdenum wire, stainless steel wire, wire and cable wire, and various alloy wires, are all drawn using diamond flat wire molds. Diamond flat wire molds, due to the use of natural diamond as raw materials, have good performance and good service life.

There are several common types of flat wire molds:

1、 When pulling soft metal (such as gold and silver), a steel mold is sufficient, and there can be multiple holes with different apertures on the steel mold.

2、 Hard alloy mold - Generally, hard alloy mold is used for drawing steel wire (steel wire). The typical structure of this mold is a cylindrical (or slightly tapered) hard alloy mold core tightly embedded in a circular steel sleeve, with a bell mouth, inlet cone, deformation (working) cone, sizing belt, and inlet and outlet angle in the inner hole of the mold core.

3、 Steel wire molds - For drawing non-ferrous metal wires, such as copper and aluminum, flat wire molds similar to steel wire molds are often used, with some differences in the shape of the inner holes.

4、 Polycrystalline molds - Fine wire drawing can be used in polycrystalline molds (synthetic diamonds), as well as flat wire molds that use natural diamonds.

The structure of the flat wire mold core can be divided into five zones according to its working properties: "entrance zone, lubrication zone, working zone, sizing zone, and entrance and exit zone". The inner diameter profile of the flat wire mold is important as it determines the tensile force required to compress the wire and affects the residual stress in the wire after drawing. The functions of each area of the mold core are: the entrance area, which facilitates threading and prevents steel wires from scratching the flat wire mold from the entrance direction; Lubrication zone, through which the steel wire is easily introduced with lubricant; The work area is the main part of the mold hole, where the deformation process of the steel wire is carried out, that is, reducing the original cross-section to the required cross-sectional size. When drawing metal on a conical surface, the space occupied by the volume of metal in the working area is a circular cone, which is called the deformation zone. Conical half angle within the workspace α (also known as die hole half angle) is mainly used to determine the size of the drawing force; The function of the sizing zone is to obtain the accurate size of the drawn steel wire; The entrance and exit area is used to prevent uneven steel wire entrances and exits from scratching the surface of the steel wire.

In the application process of flat wire molds, in order to determine high-quality wire materials and correctly operate the application cost of the mold, it is necessary to ensure stable operation of the wire drawing machinery and equipment, clean and convenient operation of each wire drawing drum and wire passing guide wheel, and strict control of its vibration dimension tolerance. If the drum or guide wheel is found to be damaged in the pipe trench, it should be immediately inspected. Excellent lubrication standards are important criteria for determining the technical performance of wire rods and increasing the lifespan of molds. Regularly check the lubrication index values, remove copper powder and residue from the lubricating grease, and clean the mechanical equipment and mold holes that do not pollute the environment. If lubrication is ineffective, it is necessary to replace them immediately and clean the intake system. The process performance of the matching mold wire, accurate and consistent operating specifications, reducing damage to the drawing drum, and solving important conditions for machine equipment operation load.

In addition, the quality factors of the flat wire mold lead to rapid wear of the flat wire mold, the asymmetric inlay between the flat wire mold blank and the mold steel sleeve, and the uneven or pore distribution of the hard alloy sleeve can easily lead to "U" shaped cracks in the wire drawing. During the laser drilling process of diamond mold blanks, the sintering marks are not cleaned thoroughly or the heating is uneven, resulting in the formation of metal catalysts and binders in the diamond layer. The design of the mold hole is incorrect, the opening of the lubrication belt at the inlet is too small, and the forming area is too long, resulting in poor lubrication of the mold hole, wear and even fracture of the mold.

Improper use of elements in metal wire drawing of flat wire molds leads to rapid wear of grinding tools. The shrinkage rate of the drawn surface is too large to cause cracking or fracture of the mold. Most cracks or cracks are caused by the release of internal stress. In any material structure, the presence of internal stress is necessary, and the internal stress generated during stretching can enhance the microcrystalline structure of the mold. But when the stretching surface shrinks too much, fails to lubricate in a timely manner, and the temperature rises, it will cause some materials of the mold to fall off, and the stress of the microcrystalline structure will significantly increase, making it easier to produce cracks or damage. The stretching axis of the wire is asymmetric with the centerline of the mold hole, resulting in uneven stress on the wire and the drawing die. The impact of mechanical vibration on wire and flat wire molds can also lead to high stress peaks, both of which can accelerate mold wear. If uneven annealing leads to premature fatigue damage of diamond flat wire molds, forming circular grooves and increasing wear of mold holes, it is easy to cause uneven hardness of steel wires. The surface of the cable is not smooth, and there is an air oxide layer, sand, or other residue on the surface, which can cause damage to the grinding tool too quickly. When the wire passes through the mold hole, the hard and brittle oxide layer and other attached impurities will slowly wear the mold hole and scratch the surface of the wire. Due to obstruction in wetting or metal debris impurities in the grease, the grinding tool is damaged. When the surface of the mold hole remains smooth, the temperature is too high, diamond particles fall off, and the mold is damaged. When the grease is uneven, especially when pulled out by metal shavings, it is easy to scratch the surface of the grinding tool and wire. Explore Superabrasive Diamonds for enhanced wire drawing dies performance. Our lapping powder suppliers ensure quality products for efficient and smooth operations.