Proposal and evaluation of a selection procedure for cast parts

Abstract

The design of casting components is a complex activity, which is usually based on guidelines scattered in the literature, or based on the designer’s accumulated experience. A single failure in the casting process selection can increase design and production time and, in critical cases, result in a collapse of the manufacturing and assembly of components. Nowadays the selection is made by prioritizing the features of the casting process, but this action could be carried out during the product development stage, assisting the designer. This could allow the project to adjust to a more viable casting process. In this context, our goal is to propose a selector for casting processes to be used during the early stages of the embodiment design. It was achieved through the use of quality function deployment and design for manufacturing (DFM) principles. Our proposal relates the component’s main functions with each process characteristic (mass, minimum section thickness, draft angle, surface finish, dimensional tolerances, minimum lot and lead time) through a correlation matrix, resulting in importance indexes for these characteristics. Furthermore, the importance indices obtained are related to the capability of each casting process discussed, providing a process rating. A checklist based on DFM principles is also provided to guide the designer when a need for improvement is observed or no processes are suited for producing the desired part. For validation, two ferrous and two nonferrous cast parts were analyzed. The results were compared with other selectors described in the literature and with processes actually used in the industry. Thus, they have shown a good relation with the other methods, especially regarding the quantitative classification determined by the proposed selector.