Development and finite element simulation of vibration assisted casting process

Abstract

In today’s highly competitive market situation, it is of vital importance for the manufacturing industry to reduce both lead-time and costs for product development. Since its first advent in 1986, as a new tool for time-reduction of product development, rapid prototyping (RP) has helped to address the challenges successfully. Recently, significant advances in materials and equipments enable most RP processes to produce physical models that are precise and strong enough to serve as master patterns for a variety of rapid tooling (RT). Many kinds of RT processes have been used for diverse applications including prototyping of die casting products. The combination of RP and plaster casting has provided useful means of making prototypes that physically simulate die casting. Unlike in standard die casting, however, plaster casting molten metal is poured into a plaster mold without additional pressure except gravity and the mold cools down much slower than a die cast mold. Because of these differences, which mainly stem from their large grain structure, and incomplete filling of the thin walls, plaster castings are not suitable enough for prototyping of die casting. The application of vibrations to solidifying metals and alloys has been found to be beneficial in a number of ways. The most notable effect of vibration is the suppression of columnar and dendritic growth and the formation of fine equiaxed grains and consequently a marked improvement in density and mechanical properties. The first purpose of this study is to propose a new plaster die casting process to improve prototyping of steel die casting, and to develop a plaster die casting machine implementing the proposed process. The RP process of LOM (Laminated Object Manufacturing) is employed to make the patterns to prepare silicone molds. Even though silicone molding is generally used for producing wax patterns, in the proposed process, it is applied to produce plaster molds repeatedly. The process combines pr...