What are the two basic categories of casting processes?

The distinction between expendable mold and permanent mold processes is fundamental to understanding casting techniques in manufacturing. Expendable mold processes involve molds that are destroyed or altered after a single use to create the final metal part. These molds are often made of sand or other materials that can easily be reshaped or recycled for new castings. This category is particularly useful for creating complex shapes and is widely used in industries that require flexibility in design.

On the other hand, permanent mold processes entail the use of reusable molds, typically made from metal, which allow for multiple uses in the production of parts. This approach is more cost-effective for mass production, as the molds can withstand repeated use without the need for significant repairs or replacements. Additionally, permanent molds tend to produce parts with better surface finishes and tighter tolerances compared to expendable molds.

The other options do not accurately categorize the casting processes in such a fundamental way. For instance, the option mentioning semi-permanent molds introduces a term that is not widely recognized as a standard classification in the industry. Sand casting and die casting are specific methods within those broader categories, but they do not encompass the full range of casting processes that can be classified under expendable and permanent molds. Thus, the correct classification into expendable