Mixed-reality lathe with hands-on operation for pre-practice training in machining skills and safety-related behaviors

In machine tool training, students must understand machining procedures and safety precautions before operating the equipment. Therefore, we propose and evaluate a mixed reality (MR) lathe training system for pre-practice training. The system allows students to perform turning operations on virtual workpieces using the levers and handwheels of a physical, powered-down lathe and includes a warning mode for hazard-zone entry and an accident mode that reproduces virtual accidents. Sixteen undergraduate students enrolled in the Department of Mechanical Systems Engineering were divided into two groups and completed a preliminary operating session, two MR training sessions, and actual machining; the safety-feedback order was counterbalanced between groups. During spindle rotation in both training and actual machining, the participants moved to a safer standing position, farther from the chuck-side hazard zone, and the number of hazard-zone entry detection events decreased significantly between the first and second MR training sessions. The machining task success rates were 37.5%, 81.3%, and 100.0% in the first and second sessions and actual machining, respectively. These findings suggest that MR lathe training has the potential to support both machining task performance and the learning of safety-related behaviors as pre-practice instruction.