Evaluation of shaping accuracy of sand mold based on stereo measurement

Casting is one of the principal techniques in the field of industrial metal production. A traditional casting process uses a mold with a pouring gate and some sprue runners through which melted metal is introduced into a mold cavity. In recent years, we have developed a novel casting process that improves the yield of production and reduces heat loss. The new process, called a press casting method, has the capability to produce a thin wall casting. In order to carry out the new casting process, mold shaping that affects the accuracy of goods must always be observed. In this paper, we propose a method for measuring a mold shape using two pairs of stereo cameras. A stereo camera method for 3D shape measurement is widely used in various fields. The reason is that the method can obtain 3D data of a shape of an object within a very short period of time without contact with the object. But search process for finding a stereo pair images takes not a little time, and it is the weakest point of the method. We achieved fast searching by using a shape model of a metal mold to form the sand mold. The experimental results showed that our proposed method is useful to evaluate position and orientation of the cavity of the mold with required accuracy and acceptable time.