Learn why castings shrink and how risers compensate for it.
Section 1
Describe the three stages of shrinkage in a casting.
Explain how risers prevent shrinkage porosity.
Relate shrinkage allowance to pattern design.
Section 2
Metal shrinks in three stages: liquid shrinkage as it cools while still molten, solidification shrinkage as it changes from liquid to solid, and solid shrinkage as the solid casting cools to room temperature.
If solidification shrinkage is not fed, it leaves internal voids known as shrinkage cavities.
Risers are sized so they solidify after the casting, feeding liquid metal to the shrinking region. Pattern makers also add a shrinkage allowance so the final solid part reaches the correct dimensions.
Section 3
Interactive animation will appear here.
Animated visualizations for this mission are being crafted and will be embedded in this space.
Section 4
Interactive activity coming in Sprint 3.
Hands-on drag-and-drop and simulation activities will be unlocked here in the next sprint.
Section 5
Answer all 5 questions correctly to unlock the next mission.