Correct Response: C. Extrusion is a manufacturing process where material is pushed through a die that has an opening with the same shape as the cross-section of the desired part. Hence, it is the technology of choice for producing a long part with a single continuous cross-section. An I-beam is a perfect example of such a part since it has a continuous I-shaped cross-section. Forging (A) would be prohibitively difficult and expensive for creating a piece as large as an I-beam. Casting (B) and metal injection (D) both require the use of a mold. To create a part the size of an I-beam, there are two molding issues that present difficulties. The first is that the molding apparatus must be extremely large. The second is that a massive amount of molten metal must be delivered to the mold, and then cooled. Both of these difficulties are avoided through the use of extrusion (C).
