How to ensure the dimensional accuracy and surface quality of lead die castings?

Lead die casting is a precision manufacturing process that aims to produce castings with stable shape and smooth surface. In the production process, in order to ensure the dimensional accuracy and surface quality of the casting, optimization is required from many aspects, including material selection, mold design, process control and post-processing.
The selection of materials is crucial to the quality of the finished product of lead die casting. High-quality lead alloys should have good fluidity and low shrinkage to ensure that the ideal effect can be achieved when filling the mold. In addition, the control of material purity cannot be ignored. Excessive impurity content may affect the strength and surface quality of the casting, and even cause internal defects. Therefore, during the smelting process, appropriate refining and impurity removal measures need to be taken to improve the overall quality of the casting.
Mold design directly affects the dimensional accuracy and surface quality of the casting. The accuracy of the mold determines the shape and size of the final product, so shrinkage compensation, the layout of the cooling system, and the optimization of the exhaust structure should be fully considered during the design. A reasonable cooling system helps to control the solidification rate, make the internal structure of the casting uniform, and reduce deformation and cracks. Good exhaust design can effectively exhaust air and volatile gases, avoid porosity defects, and thus improve the surface finish of castings.
Process control runs through the entire production process of lead die casting, including temperature control, injection speed, pressure adjustment and other links. The temperature of the lead alloy in the molten state should be kept stable to ensure appropriate fluidity and reduce cold shut defects. The matching of injection speed and pressure is crucial. Too high speed may cause flash and mold damage, while too low speed may cause insufficient filling and cold shut defects. Reasonable adjustment of process parameters can effectively reduce dimensional errors and improve the overall quality of castings.
After the casting is formed, the post-processing process also plays an important role. During the cleaning process, excessively rough grinding should be avoided to avoid damaging the surface quality. For castings with high precision requirements, mechanical processing can be used for trimming to ensure that the size meets the expected requirements. In addition, surface treatment processes such as polishing and coating can also improve the corrosion resistance and appearance quality of castings, making them more in line with use requirements.