the effect of bridge orientation in casting machine on the castability and quality of base metal castings

introduction: the aim of this study was to evaluate the effect of bridge orientation in casting machine on castability and quality of base metal castings. methods: three groups of patterns with different direction and lengths in casting machine were casted and then studied qualitatively and quantitatively using mean and standard deviation in table of frequency. results: larger nodules and porosities were on the joints of sprue in horizontal specimens (p=0.01 and 0.048, respectively). there was no significant difference in castability between 3-, 5- and 6-unit bridges in relation to their direction in casting machine (p=0.5). an increase in bridge length led to more variation in length and width. the position of bridges also played an important role in the length variation in bridges. conclusion: the direction of bridges had no effect on base metal castability but a vertical position resulted in a better casting quality and an increase in length of the bridges caused more defects in castings.