One of the important parameters is the inlet zone of the wire drawing die, which needs to ensure that the contact point of the wire when entering the die is at the same height as the compression zone of the drawing die, and at the same time facilitate the smooth entry of the wire. The inlet zone should have a smooth profile that connects the lubrication zone to the compression zone to ensure that the lubricant reaches the working surface of the wire drawing dies.
The role of the lubrication zone is to store the lubricant and transport it to the work area. The cone angle of the lubrication zone varies depending on the lubricant viscosity, the wire diameter and the length of the lubrication zone. In order for the liquid lubricant to enter the working area smoothly, a larger lubrication zone cone angle is generally selected. If the cone angle is too small, the lubricant cannot enter, the lubrication effect is poor, and it may even lead to lubricant clogging. However, if the cone angle is too large, it is not conducive to the formation of hydrodynamic pressure effect. In addition, the length of the lubrication zone also affects the lubrication effect. In general, the longer the lubrication zone, the better the lubrication effect.
The work area is the area where the wire is plastically deformed, and the dimensional parameters include the work area cone angle and the work area length. The taper angle of the working area is a parameter of the wire drawing die, which determines the magnitude and distribution of the pressure applied to the inner hole of the drawing die, as well as the influence of the drawing stress on the mechanical properties of the wire. The work area cone angle varies with the drawing environment, and there is an optimal range of work area cone angle to ensure low drawing stress. Due to the difficulty of determining the concentricity of the wire axis and the inner hole axis of the wire drawing die, coupled with the increase in the wire diameter due to the wear of the inner hole of the drawing die caused by the previous drawing process, both factors will cause the wire to deform outside the deformation zone. Therefore, the length of the work area should be larger than the length of the actual deformation zone.
The diameter dimension of the sizing zone is determined according to the tolerance of the wire rod and the elastic deformation that occurs during drawing, and the negative tolerance size of the wire rod is usually selected taking into account the service life of the die. When determining the length of the sizing zone, the following requirements need to be met: sufficient wear resistance, energy consumption during the drawing process and reduced likelihood of wire breakage. A long sizing zone increases friction, heat, and energy consumption, and can lead to wire diameter reduction or breakage. If the diameter zone is too short, it will lead to wire shaking and slub shape, and at the same time accelerate the wear of the inner hole of the wire drawing die, resulting in size out-of-tolerance. In general, the larger the diameter of the wire, the shorter the length of the sizing zone.
The decompression zone is that after the wire passes through the sizing area of the wire drawing die, it enters the inverted cone area after great compression, so that the diameter of the wire becomes larger, and the surface directly touches the decompression zone. If the decompression zone of the drawing die is too rough, it will cause scratches on the surface of the wire.
The outlet zone forms an angle of 90 degrees. Such an angle facilitates an outlet with a large width, allowing the wire drawing dies to be restored to its original size several times without having to be re-machined. The exit zone is usually considered unimportant, but if the drawing dies does not have an exit zone, the trailing edge of the sizing strip may crack or peel off, causing damage to the drawing die.
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