Changzhou Shen Litong Mould CO.,LTD

1. Entrance Zone Design: 1）. The entrance zone mainly serves to guide the metal wire to smoothly enter the die. Its shape is usually a bell mouth, with an angle generally between 60° and 90°. For example, when drawing copper wire, the entrance angle can be set at around 70°, which can reduce the resistance when the wire enters the die. 2）. The length of the entrance zone is usually determined based on the wire diameter and the overall size of the die, generally 1 to 2 times the wire diameter. The surface roughness of the entrance zone is relatively low, typically Ra 0.8 - 1.6μm, to prevent scratching the wire. 2. Lubrication Zone Design: 1）. The lubrication zone is designed to form a lubricating film on the surface of the wire, reducing the friction during the drawing process. The length of the lubrication zone is generally 3 to 5 times the die diameter. 2）. The structure of the lubrication zone can be in the form of annular grooves or helical grooves. The width and depth of the annular grooves are generally between 0.2 and 0.5mm, and the pitch of the helical grooves can be designed according to the drawing speed and lubrication requirements, generally between 1 and 3mm. 3. Compression Zone Design: 1）. The compression zone is the core part of the die, determining the degree of deformation and dimensional accuracy of the wire. The length of the working zone is determined based on the drawing ratio and the material of the wire. The larger the drawing ratio, the longer the working zone length relatively. 2）. The shape of the compression zone is generally conical, with a cone angle usually between 3° and 12°. For harder metal wires, the cone angle can be appropriately reduced to avoid wire breakage. The diameter accuracy of the working zone is very high, with a tolerance generally controlled within ±0.005mm. 4. Diameter Control Zone Design: 1）. The diameter control zone is mainly for precisely controlling the final size of the wire. The length of the diameter control zone is generally 0.5 to 1 times the wire diameter. 2）. The diameter tolerance of the diameter control zone is extremely strict, generally within ±0.002mm, to ensure uniform and consistent wire size after drawing. 5. Pressure Relief Exit Zone Design: 1）. The pressure relief exit zone is designed to allow the drawn wire to smoothly exit the die. The shape of the exit zone is a bell mouth, with an angle generally between 30° and 60°, and a length of 0.5 to 1 times the wire diameter.

In the drawing process, it is easy to face that the dies are not used for a long time, but the holes are larger or elliptical, wire break frequently, and the wire surface is not polished, which brings difficulties to the operation and causes losses to the production. There are many reasons for these problems, mainly including the following factors: 1. Input wires The surface quality of the input wires not good, such as it is elliptical, overlapped, spotted, uneven, etc., which make it difficult for drawing. In addition, the inherent quality of the wire itself, such as mechanical properties, chemical composition, metallographic structure, etc., are all relevant to the quality of the product after drawing. 2. Drawing equipment The drawing equipment installation is not stable and with big vibration, the drawing capstans are grooved or the wire drawing speed is too fast, etc. These will affect the drawing quality. 3. Wire drawing dies The angle of the dies hole is inconsistent or does not meet the standard. In addition, the unreasonable die series, mainly refers to the excessive or small amount of compression in each pass. 4. Lubricant When drawing, lubricating oil is added to form a thin film on the metal surface within the working cone. Angle due to pressure. Lubrication is added during drawing to make the metal surface form a thin film due to pressure in the working cone angle, so that there is no direct friction between the wires and the die holes, which reduce friction and thus it can reduce the power load of the equipment and prolong the service life of the drawing dies. And, it is also need to reduce the drawing temperature. There must be sufficient pressure to make the cooling of dies and wires good. The high temperature of the wires will damage the lubricant and die holes during drawing. 5. Die cores For drawing different material wires, it should choose the proper die cores to improve the service life of the dies.

In the production process, It will cause a great consumption to the drawing dies, which not only increases production cost, but also affects production efficiency due to frequently stop the production line to change dies. The timely or regular maintenance of the dies will extend its life and enable the manufacturer to obtain better economic benefits. 1. Cleaning: before maintenance, the surface of the drawing dies should be cleaned to remove oil stains and impurities. Then wipe the stains in the holes with medical cotton. 2. Inspection: checking the damage of the dies and then classify dies into polishing maintenance and reaming maintenance. 3. Polishing: pay attention to the time and smoothness after polishing during the polishing operation. 4. Reaming: before reaming, determine the target aperture to be enlarged, and then implement it in steps. 5. Regular maintenance: usually, the company that uses the dies should work out the maintenance cycle of the dies according to the production process requirements. And do maintenance for the dies regularly.