Jawaharlal Nehru Technological University Hyderabad B.Tech II Year PRODUCTION TECHNOLOGY Previous Question Paper (March - 2022 - R13)

Casting is a highly versatile manufacturing process capable of producing parts ranging from a few grams to several hundred tonnes. In terms of size, it can accommodate miniature components like dental implants or watch parts, as well as massive industrial components such as ship propellers, turbine housings, and machine tool beds. The process is uniquely suited for complex geometries that are difficult or impossible to achieve through machining or welding.

Regarding shape, casting allows for the creation of intricate internal cavities and complex external contours by using cores and multi-part molds. It can produce parts with varying wall thicknesses, curved surfaces, and non-symmetrical features in a single operation. Because the material is poured in a liquid state, the design is limited primarily by the ability to remove the pattern from the mold and the flowability of the molten metal, rather than the mechanical constraints of cutting tools.

Advantages: Investment casting provides excellent surface finish and high dimensional accuracy, often eliminating the need for subsequent machining. It can cast complex shapes with thin walls and intricate details that are impractical for other methods. It is compatible with a wide range of alloys, including those that are difficult to machine or forge, such as high-temperature superalloys.

Limitations: The process is relatively expensive due to the high cost of pattern production and the labor-intensive nature of mold preparation. It is generally restricted to smaller parts, and the cycle time is long compared to die casting or sand casting, making it less suitable for high-volume, low-cost production.

Applications: It is widely used in the aerospace industry for turbine blades and engine components, in the medical field for surgical implants and dental prosthetics, and in the automotive and defense sectors for precision parts like impellers, gears, and firearm components where high integrity and complex geometry are required.