A machinist who has learned to weld has undergone what type of training?

The correct answer is cross-training. This type of training occurs when an individual learns new skills that are typically outside their primary area of expertise. In this case, a machinist, who primarily focuses on machining processes, expands their skill set by learning how to weld. This versatility in skills allows for greater flexibility in the workplace, as the individual can perform multiple roles or tasks, making them more valuable to their employer.

Cross-training also encourages a better understanding of interconnected processes, enhances teamwork, and contributes to a more adaptable workforce. Since the machinist is not only working with machinery but also acquiring a new skill in welding, this demonstrates the essential nature of cross-training in manufacturing settings, where diverse skill sets can lead to increased efficiency and productivity.