While there are a lot of advantages associated with gravity die-casting, there are also some difficulties and restrictions to accommodate:
- The process has distinct requirements that impose limitations on design flexibility. These molds are designed to allow molten metal flow driven solely by gravitational forces, in contrast to low-pressure and high-pressure die casting, which employ external pressure for mold filling. Achieving specific design features, like thin walls and intricate geometries, can be challenging within the confines of this method. This is particularly true in that the cavity must split in two and release the finished part, because undercuts are essentially impractical in gravity die-casting tools.
- It necessitates a moderately high initial investment in terms of tooling and equipment- primarily the tooling cost, if the foundry is already established. This is much lower than pressure die casting, which requires higher-cost tooling and considerable equipment investment. Establishment costs are also significantly higher than sand casting which is typically very low cost in setup and pattern making.
- In comparison to alternative casting methods, gravity die casting typically involves longer lead times. Fabrication of the permanent molds can take considerably longer than making wooden or rapid prototype patterns for sand casting or 3D printed wax masters and ceramic dip coating to make ceramic shells.
- Gravity die casting is most suitable for producing relatively small aluminum and zinc alloy castings. The method is less appropriate for manufacturing larger components, as the cost of the die is such that low- or high-pressure casting methods become in-range for cost.
