Proposal and evaluation of a selection procedure for cast parts

Abstract

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.

Web platform for casting process selection

“…The Web platform was developed using html and JavaScript, and was based on the Santos et al (2017) selector. The methodology embedded on this Web selector combines QFD and DFM concepts and aims to choose the most appropriate casting process during the product design phases (ELGH, 2014; KNIGHT; COWELL; PREDDY, 1995; NICHOLDS; MO; BRIDGER, 2014).…”

“…To complete the selection, a checklist is provided in order to correct the component's parameters, or to adapt the project to fit the characteristics of the process in order to make it more efficient. Santos et al (2017) propose to differentiate between ferrous and non-ferrous metals, since some casting processes cannot be applied to both cases. The characteristic values which should be provided by the designer are: mass, minimum section thickness, draft angle, surface finish, dimensional tolerances, minimum lot and lead time.…”

“…In the selection matrix, to obtain the prioritization, the values of characteristics are compared to the casting processes capabilities. For each process characteristic, Santos et al (2017) established four levels for the "value of the characteristic", namely: 1) extreme minimum, 2) minimum of 3) maximum and 4) extreme maximum. These values are matched to a database which is already built into the proposed Web platform.…”

“…In order to consider the process characteristics from the embodiment design, and based on the DFM principles, a checklist is also provided as a guide to help designers review their project goals. The checklist is a list of functions to verify and document the selection routine, to keep the process organized and simple (SANTOS et al, 2017). This tool should be used for the highest ranking process and all the fields in the list must be checked.…”

“…Comparison between the proposed selector (1), American Foundry Society platform (2), and the processes used in industry (3). Santos et al (2017), thus producing a wide separation between maximum and minimum extremes. This particularity makes the web selector process much acceptable when the characteristics of the components are compared to the platform database.…”