What are the advantages of permanent mould casting and gravity casting?

3.1. What are the advantages of permanent mould casting?

Permanent mould casting is a metal casting technique used to create complex and intricately shaped metal parts with high accuracy and surface finish. Major types of permanent mould casting include: die casting, gravity, slush, low-pressure, and pressed (http://www.taiwan921.lib.ntu.edu.tw/mypdf/mf05.pdf).

In permanent mould casting, a reusable mould, typically made from materials like steel or cast iron, is employed to shape the molten metal into the desired form. The mould consists of two halves that are clamped together before the casting process begins. One half of the mould is stationary, while the other is movable. The mould is designed with the intended part's shape and features, including cavities, cores, and runners for the molten metal to flow.
Although encountering some limitations such as higher initial costs and limited material selection, permanent mould casting has the following advantages making it a popular choice:
1. Improved surface finish: The smooth interior surfaces of the mould result in better surface finish on the cast part compared to non-permanent mould casting such as sand casting.
2. Dimensional accuracy: Permanent mould casting offers greater precision and consistency in part dimensions and features.
3. Reduced porosity: The controlled mould environment and reduced exposure to air help minimise porosity in the cast parts.
4. Higher production rate: Permanent mould casting allows for a relatively higher production rate compared to investment casting.
5. Suitable for complex shapes: The mould can incorporate intricate details and features, making it well-suited for producing complex parts.

Other advantages of permanent mould casting include:

1. The reusable mould
2. Rapid solidification
3. Cost-effectiveness in the long run
4. A lower scrap rate

Overall, permanent mold casting strikes a balance between the advantages of sand casting and investment casting, making it a suitable choice for various applications where dimensional accuracy, surface finish, and cost considerations are important.

3.2. What are the advantages of gravity casting?

Gravity casting, as one type of permanent mould casting, also has the above advantages. It has particularly the listed advantages:
1. Precision, consistency, and accuracy: Gravity casting produces parts with precise dimensions and tight tolerances, suitable for intricate designs.
2. Smooth surface finish: The controlled filling process results in smooth and refined surface finishes on cast parts.Smooth surface finish: The controlled filling process results in smooth and refined surface finishes on cast parts.
3. Minimized defects: Reduced porosity and controlled cooling lead to fewer defects in the final castings.
4. Complex geometry: Gravity casting can accommodate complex shapes and details, making it versatile for various part designs.