Which of the following operations utilizes a stationary workpiece?

The operation that utilizes a stationary workpiece is milling. In milling, the workpiece is typically fixed in place on a machine table while the rotating cutting tool moves across it to remove material. This allows for precise control over the cutting action, as the stationary workpiece provides a stable base to achieve accurate dimensions and surface finishes.

In contrast, turning involves a rotating workpiece that is held in a chuck or spindle while the cutting tool moves linearly along the length of the component. Electrical discharge machining (EDM) also commonly involves the movement of the workpiece but utilizes electrical discharges to remove material, which requires the workpiece to be held securely but does involve some level of movement or repositioning during the process. Welding generally uses a stationary workpiece, but this is not its defining characteristic, as it can also involve moving components together.

Thus, milling is distinctly characterized by the workpiece remaining stationary while the tool performs the cutting operation, aligning it with the question's requirement.