Atlas of Casting Defects
Shape
The geometry does not conform to the drawing
varies
Opposite gate locations
Visual inspections and customary dimensional inspection tools
Distortion of the casting occurring at wax injection, pattern assembly, or casting cooling.
| Area | Possible Cause | Potential Correction |
|---|---|---|
| Other (Casting design) | Geometry of the casting and or running system causing uneven contraction |
Minimize uneven stresses that develop with solid-state metal contraction occurs |
| Other (Mold design) | Improper gating system design |
Design the gating and runner system to prevent uneven stresses |
| Other (Mold design) | Ingates contracting and pulling part of the casting |
Examine the runner system and modify to reduce stresses |
| Wax | Improper wax pattern handling ejected from die |
Modify release agent spraying technique, frequency. Add ejector pins |
| Wax | Improper wax pattern storage |
Store patterns in a manner to prevent distortion |
| Wax | Ingates contracting and pulling part of the casting |
Examine the runner system and modify to reduce stresses |
| Wax | Improper gating system design |
Design the gating and runner system to prevent distortion |
| Shell | High strength mold preventing even contraction |
Reduce the mold strength |
| Other | Knockout conducted at too high a temperature |
Knockout at a lower temperature |
| Foundry | Improper casting handling |
Ensure cast molds are handled with care – especially at high temperature |
| Other (Heat treatment) | Stresses induced during heat treatment |
Ensure the castings are correctly supported during heat treatment. Use the slowest quenching method that will achieve the required hardness |