Shrinkage is an inevitable problem during product processing and production, which can affect the appearance quality of the product. It usually appears in thicker positions. Generally speaking, as long as the shrinkage does not affect the performance of aluminum castings, it is considered qualified. However, for some important parts such as cooling water channel holes or lubricating oil channel holes in automobile engine cylinder blocks, shrinkage is not allowed to be considered qualified. A certain enterprise's aluminum alloy engine crankcase is cast using a Butler 28000kN cold chamber die-casting machine, The material is ADC12 alloy, and the casting billet has a mass of 6.3 kg. During the later X-ray inspection process, it was found that the oil passage of the second crankshaft bearing hole had shrinkage holes, which are about 8 mm away from the oil passage, posing a significant risk of oil leakage.