What defines a jig in manufacturing?

A jig in manufacturing is specifically designed as a work holding or positioning device that is not fixed to the machine bed. This feature allows it to be easily repositioned or used on various machines, enhancing flexibility in the manufacturing process. Jigs are typically engineered to guide the tools or workpieces during machining operations, ensuring accuracy and efficiency.

The ability to be mobile is crucial for jigs, as this adaptability allows for quick tool changes and a range of operations without the need to reconfigure fixed equipment. This characteristic distinguishes jigs from fixtures, which are often stationary and provide support and alignment for workpieces but do not guide the cutting tools.

The other choices either misrepresent the function of a jig or describe features that are not accurate for jigs in a manufacturing context. For example, suggesting that it is unmovable contradicts the definition of the jig's purpose, while stating it is solely for cutting purposes ignores its broader applications in guiding operations. Thus, option B accurately defines a jig by highlighting its key feature of not being fixed to the machine bed, reflecting its role in versatile and efficient manufacturing processes.