1. Drawing die core structure and function. According to the working nature of the wire, the drawing dies core is usually divided into five areas: the entrance area, the lubrication area, the working area, the sizing area, and the exit area. Friction with the wire drawing dies; Lubrication area: Use lubricant to increase the lubricity of the wire; Working area: It is the key part of the dies hole. The steel wire completes the deformation process in this area. It can control the section size of the steel wire according to the specified section size. In drawing the conical surface metal, the space occupied by the volume of the steel wire in the area is a circular cone, commonly referred to as the deformation area. How much force is used in the drawing is mainly determined by the cone half angle α; sizing area: to obtain the exact size of the drawn wire; exit area: to ensure that the wire exits the die mouth smoothly to avoid scratches on its surface. In addition, the magnitude of the tensile force when compressing the wire and the residual stress in the wire after the drawing is mainly determined by the inner diameter of the dies.
2. The entrance angle, working area and sizing area influence the wire drawing process.
① Entrance angle. When drawing, the wire rod first reaches the entrance area of the mold core. Suppose the taper angle of the inlet area is too small. In that case, the contact area between the wire and the inner hole will increase, thereby increasing the frictional force. The wire is not easy to bring in the lubricant, which reduces the lubrication effect and increases the die loss. Properly increasing the entrance angle can reduce the friction between the wire and the wire drawing die, ensure that the lubricant is brought in smoothly, increase the degree of lubrication, and thus protect the die core. The adjustment of the entrance angle makes the surface quality of the wire closer to the technical requirements and prolongs the service life of the drawing die.
② Work area. When drawing wire, the longer the working area, the smaller the friction force and the more uniform the distribution, and the smaller the wear degree of the inner hole of the wire drawing die, the longer the wire drawing die is used. The narrower and longer the working area, the better it can prevent the lubricant from exiting the inlet end of the drawing die. The smaller and shorter the working area, the smaller the usable area in the hole, the higher the friction force, the more serious the wear and the higher the material cost.
③ Sizing area. The final step in determining wire size is in the sizing area. If this area is short and not straight, it can lead to quality defects in the wire. The shorter the sizing belt, the greater the product size tolerance and the greater the wear of the drawing die. The straighter the sizing area, the higher the wire drawing accuracy, the fewer quality defects, the lighter the mold wear, and the longer the use. Based on the above analysis, it can be seen that by optimizing and adjusting the hole pattern of the wire drawing dies, the wear degree of the die can be reduced, and its service time can be prolonged. Given this, when manufacturing molds, it is necessary to strictly control the manufacturing accuracy and continuously optimize the hole size to achieve the goal of saving costs, reducing consumption and improving production efficiency.
