Wire is machined by passing through small holes intungsten carbide wire drawing diesto reach a specified diameter. The process is called drawing. Although the principle of wire drawing is very simple, it is rather complicated from the mechanical point of view. Although many theories and speculations have been published to explain the mechanical principles involved in wire drawing, many aspects remain unexplained. Drawing dies are probably the simplest type of tool used in industry to deform metals. The most basic form of a drawing die is a metal block with a tapered hole. People have used this structure of the wire drawing die for more than 500 years, hard alloy wire drawing die is still based on the above basic form, but in some aspects made improvements. In 1923,Karl Schroter discovered that a mixture of tungsten carbide powder and drilling, iron or nickel (10% by weight) metals could be pressed and sintered to produce a material with low porosity, high hardness and high strength. He produced die cores that could be used to draw tungsten wires and successfully promoted them to the electric lamp industry. Soon this new material is widely used in the nonferrous metal wire industry. In the mid-1930s, the cemented carbide mould was also widely used in the us steel wire manufacturing industry. Modern cemented carbides are similar to the materials schroter produced in those days.

Production of steel wire and tungsten carbide wire drawing dies using a large number of die hole diameter and advised 3, 10 mm hard alloy drawing die. Die hole grinding BBB 0 0.5~1 mm. The grinding of each part of the hole with the working belt takes the most time. For example, by dk5 mm heavy grinding to 5.5 mm, rough grinding to dozens of minutes, fine grinding at least 3, 5 minutes. Generally, the grinding cone is first mechanically rough ground with boron carbide grinding paste and taper point steel needle, and then fine ground by hand with diamond powder grinding paste and steel or wood grinding needle. The institute of superhard materials, part of the Soviet academy of sciences, worked with a number of factories to develop a new method of electrolytic cathode grinding. Grinding is divided into two steps: first, in the sub-micro cutting conditions, electrolytic method of high efficiency rough grinding; Then mechanical fine grinding (polishing), so that the surface roughness Ra up to 0.08 micron. The same needle (cathode) is used for both steps. During rough grinding, the die hole of the drawing die is concentric with the grinding needle (cathode). Fine grinding, grinding needle up and down and around at the same time. The spindle head frame of the mould grinding machine can ensure that the polycrystal on the grinding needle is always in close contact with the grinding hole surface. The needle (cathode) is a tapered steel needle with a ring of cylindrical polycrystals embedded in the needle. 2-0.3 mm. Polycrystals are made from scrap diamond molds and polished with diamonds.

Due to the wide use of high-speed wire drawing machine, the research on the design of high-speed wire drawing die for high-speed wire drawing machine and extending the service life of the die has been carried out at home and abroad, such as the improvement of the die core material and the research on the pass theory and so on.

Related link:

http://www.wococarbide.com/Library/libraryinfo/id/1397

Posted by: hannahgwendolyn at 09:38 AM | No Comments | Add Comment
Post contains 573 words, total size 4 kb.