| Design Criteria -- Review the design, looking for flat
sections that can be lightened and long thin ribs that need to be tapered to promoted
directional solidification |
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- Large flat sections are difficult to feed and to develop good
directional solidification. Lightener holes eliminate the problem of isolated flat
sections; they also save weight. But they need to be placed in "non-structural"
areas.
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- Adding taper along a rib or section from the cold region to the hot
region promotes directional solidification and prevents shrinkage pores.
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