High-precision (near-net-shape) casting is becoming increasingly necessary for die-cast automobile parts, both to improve performance and to reduce cost. Reducing material cost and processing time by reducing the amount of metal left to be cut away is a major issue. As the greatest amount of machining necessary after the die-casting process occurs in the boring of cylinder holes, reducing the amount of metal to be bored was made the goal of this study. It was considered that the dimensional and shape accuracy of the cylinder hole in the casting process would have a major influence on the reduction of the amount of cutting, so the casting conditions were reviewed with the aim of improving casting accuracy. An optimal combination of factors and levels was obtained through parameter design by focusing on transferability, and the maximum dimensional difference between die and casting was reduced to 1/1.74 of the value in the existing die casting process. This reduced the amount of metal to be cut by 14 grams per manufactured unit, leading to a projected annual saving of 26 million yen.
