Effects of Mold Designs on Quality of Aluminum Die Casts (Part Two)

4. The formulation and implementation of the die casting process
The formulation and implementation of the die casting process are related to the quality of the die casting mold and equipment and the technical level of the operator. Lax implementation of die casting processes and their main parameters will cause shrinkage porosity, deformation, incomplecte pouring and unqualified sizes of die casting parts.

The relationship between the quality of the die casting part and the mold
Molds are the main tools for die casting parts; therefore, overall structures of molds and structures of molds' parts should be reasonable to make molds easily manufactured and used, safe and reliable when molds are designed. Molten metal smoothly flowing in the molds can evenly cool die casts in order to make molds not deform in die casting processes. In addition, molds' materials should be appropriately chosen according to production lots and materials.

1. Reasonable structures of molds and molds' components
From the perspective of strength, it would be better to design the mold's component as a whole. The mold will be sturdy and durable, and it won't deform or be damaged easily. However, if shapes of die casts are complex, molds' components will also be complicated, which will make mold processing difficult and processing accuracy not high. If the mold's part is made as a combination, the processing will be greatly simplified; high processing accuracy can be obtained easily and die casts with high quality can be gained.

2. Numbers of cavities
The number of the cavity is determined by the equipment capacity, the complexity of the mold processing, the production lot as well as the accuracy of the die cast, especially for multiple cavity molds. Die casts' performance of every cavity is inconsistent due to difficult mold processing and big error of dimensional accuracy. It would be better to choose a mold with a cavity when the die cast is required to have the high accuracy and the complex geometric shape. Small die casts depend on different conditions.

3. Designs of running gate systems
Running gate systems not only are channels for molten metals to fill die casting cavities, but also can regulate factors such as flow velocity of molten metals, pressure transmission, discharge conditions and heat equilibrium of die casting molds. Therefore, we should not only analyze structural characteristics, technical requirements, alloys' types and their characteristics of die casts, but also need to consider types and characteristics of die casting machines in order to reasonably design running gate systems.