The places where cold isolation occurs in aluminum alloy die castings are usually the wide surface and thin walls of the casting far from the gate. It is due to the fact that when the metal flow is divided into several strands, the flow front of each strand has shown a condensing state, which is called the solidification front, but it is still filled under the impetus of the following metal flow, and the metal flow that meets it also has a solidification front. At this time, the solidified layers that meet can no longer be fused, and there is a gap at the junction. The two metal flows are butted with each other, but they are not fully fused and there is no debris in between. The bonding force of the two metals is very weak, and the serious cold separation The use of castings has certain obstacles, which should depend on the conditions of use of the castings and the degree of cold isolation. Measures must be taken to remove the flow marks and cold water mark defects in the aluminum alloy die-casting process, so as not to affect the quality and normal use of the die-casting parts.