Property |
Green Sand Casting |
Lost Foam Casting |
Complex Internal Features and Part Consolidation. |
Complexity
determined by sand core
limitations -- geometry, strength, and cost. |
Extensive and complex internal features
(as small as 0.20") available in lost
foam, based on detail duplication and pattern assembly in foam. |
Dimensional Tolerances |
+/- 0.030" is typical
depending on part size, complexity, and geometry |
+/- 0.005"-0.010" is typical depending on part size, complexity,
and geometry.
|
Surface Finish Capabilities |
250-600 microinches typical.
Depends on grain fineness of sand. |
60-250 microinches typical. Depends on bead size and ceramic coating grain
fineness.
|
Feature Accuracy |
Core movement and shift between mold halves across the parting
line limit feature accuracy. |
No cores or mold halves to shift and degrade feature accuracy. |
Parting Line and Draft Angles |
Parting lines and draft angles are necessary for molding. |
No parting lines in the mold and minimal draft on tools. |
Environmental Costs |
Sand recovery requires binder removal and
time consuming sand clean-up |
Sand is binder free, so it can be
easily and rapidly recovered at low cost. |
Tool Life |
Wear on wood and metal tools from
sand abrasion |
Low wear and long life with aluminum
tool |