SUNConferences, SAIIE NeXXXt

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An application of control chart and fish-bone diagram for minimizing defects in sand casting process.
Cindy Sithole, Kasongo Didier Nyembwe, Peter Olubambi

Last modified: 2019-07-31

Abstract


Sand casting process is widely used in South African foundries for the production of small to medium castings. The process involves pattern making, moulding, metal pouring, shakeout and fettling. The quality of the final casting strongly depends on the quality of the moulding sand. To that end, sand control must be put in place to monitor and control the properties of the moulding sand. This generally takes the form of sand testing to determine various properties that are recorded and interpreted to determine appropriate control actions. Unfortunately, this sand control approach has several shortcomings in terms of reliability and predictability. The purpose of this study is to explore the benefits and application of control chart and fishbone diagram in sand casting process as an alternative control methodology in order to decrease the quantity of casting defects in green sand foundries. Sand casting data were obtained from a local greensand casting foundry including casting defects and sand properties. The control chart was used to study and measure the amount of variation in sand casting properties due to the observed casting defects in the foundry. The fish bone was then applied to determine the sources of variations that lead to major casting defects. The results of this exercise show that a better understanding and prevention of casting defects could be achieved in the foundry.


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