How to repair die-casting molds
Publish Time: 2024-06-11
When determining the injection speed, the maximum speed should not exceed 100m/S. Too high speed will cause corrosion of the die casting mold and increase the deposits on the cavity and core; but too low speed will easily cause defects in the casting. Therefore, the corresponding minimum injection speeds for magnesium, aluminum, and zinc are 27, 18, and 12m/s, and the maximum injection speed of cast aluminum should not exceed 53m/s, and the average injection speed is 43m/s.
During the processing, the thickness of the thicker template cannot be guaranteed by stacking. Because the bending deformation of the steel plate is reduced by 85% when the thickness is 1 times, the stacking can only play a stacking role. The bending deformation of two plates with the same thickness as a single plate is 4 times that of a single plate. In addition, when processing the cooling water channel, special attention should be paid to ensuring concentricity in the processing of both sides. If the head corners are not concentric with each other, then during use, the corners of the connection will crack. The surface of the cooling system should be smooth, and it is best not to leave machining marks. EDM is increasingly widely used in mold cavity processing, but a hardened layer is left on the surface of the cavity after processing.
This is caused by the self-carburization and quenching of the die-casting mold surface during processing. The thickness of the hardened layer is determined by the current intensity and frequency during processing. It is deeper during rough processing and shallower during fine processing. Regardless of the depth, the mold surface has great stress. If the hardened layer is not removed or the stress is not eliminated, cracks, pitting and cracking will occur on the mold surface during use. To eliminate the hardened layer or relieve stress, you can: ① Use oilstone or grinding to remove the hardened layer; ② Remove stress below the tempering temperature without reducing the hardness, which can greatly reduce the surface stress of the mold cavity.
The casting process should be strictly controlled during the use of the mold. Within the scope of the process permission, try to reduce the casting temperature of the aluminum liquid, the injection speed, and increase the mold preheating temperature. The preheating temperature of the aluminum die-casting mold is increased from 100~130℃ to 180~200℃, and the mold life can be greatly improved.
