With the advancement of metal additive manufacturing technology and the digitization of equipment, the need for user-centered design in HMI (Human-Machine Interface) has become increasingly apparent. However, research on design guides and usability test for industrial equipment has been lacking. Therefore, this study applied user-centered design principles to design and manufacture a prototype HMI for metal additive manufacturing equipment, followed by a usability test of the HMI prototype. Based on usability testing and in-depth interview analysis, this study proposes UX/UI design guidelines for user-centered industrial equipment HMI. The usability evaluation highlighted the need to improve the visibility of the system's real-time status, enhance interface intuitiveness for error prevention, and address emergency situations. It is crucial that the interface reflects both the visible and invisible states of the equipment, considering that the operation targets are mechanical equipment but the operating devices are HMI screens. Furthermore, for industrial equipment with numerous complex functions, it is essential to restrict or guide user actions through permission settings. Through the industrial PBF (Powder Bed Fusion) method metal additive manufacturing equipment HMI design guides proposed by this study, we anticipate the development of user-friendly and productivity-enhancing HMI designs.