The fundamental principles for preventing shrinkage porosity and shrinkage cavities in castings involve formulating correct casting processes based on the shrinkage and solidification characteristics of the alloy. This ensures that good compensation conditions are established during the solidification process of the casting, converting shrinkage cavities into shrinkage pores as much as possible, and making the shrinkage pores appear at the solidification site of the casting. Consequently, a riser of a certain size is placed at the solidification site of the casting, allowing aluminum castings to concentrate shrinkage pores within the riser, or the gating is opened directly at the solidification site to provide compensation. To establish good compensation conditions during the solidification process, the primary reason is to control the solidification direction of the casting to conform to the "directional solidification principle" or the "simultaneous solidification principle."

The location of the injection system significantly affects the temperature distribution of castings. Adjusting the pouring temperature and speed of the molten metal can enhance directional solidification or simultaneous solidification. Setting risers on the thick-walled sections or hot spots of castings is an effective process measure for preventing shrinkage cavities and shrinkage porosity in aluminum castings. The combined use of risers, feeders, and chillers is an effective measure to eliminate shrinkage cavities and shrinkage porosity in castings.