Virtual training for the maintenance of machine tools
Authors: Eckardt Robert , Goldhahn Leif 
Published: June 2024

In the course of digital change, systems and processes are increasingly being planned, adapted and tested using computers. Innovative technical aids are needed to guide staff and relieve them physically and mentally in order to cope with flexibly changing work tasks such as the maintenance of machine tools.Virtual reality (VR) offers attractive opportunities for employee training and enables the practical acquisition of knowledge. The use of VR is based on the idea that experiences are sustainable and do not have to be learned in the abstract.The interaction between man and machine plays a decisive role in the operation and maintenance of machines. Efficient interaction is necessary to minimize errors and maximize efficiency. Traditional training methods reach their limits here, as they are often not realistic enough and employees find it difficult to apply what they have learned in practice.A virtual learning environment, which virtualizes a real work area, uses integrated, didactically prepared scenarios to clearly convey methodical knowledge and practical skills to increase operating safety on production systems. The virtual training thus enables employees to practice specific technical sequences of actions and sub-actions or hand movements in a realistic manner and to learn them in a sustainable way for later practical use. The focus is on typical operating actions such as deliberate, sequential actuation or disassembly for the maintenance of add-on parts on machine tools.In order to ensure the desired learning success (error-free, safe execution of the real work task) and employee acceptance, the correct structure of the operating sequences and an exact representation of the graphic interfaces are conducive to learning and acceptance.The advantages of using virtual learning environments were demonstrated using the example of the virtual commissioning of a machine tool. For example, after successfully completing the virtual learning scenario, the test subjects felt much more confident when carrying it out on the real machine.However, it also became clear that VR-based learning environments with complex virtual learning scenarios also require further development. For example, the use of VR hardware (VR glasses and controllers) and software has potential for improvement in terms of user-friendliness. Tests with users showed that handling the VR hardware was problematic at the beginning. The virtual learning scenarios often could not be completed because the virtual, user-induced movement and implementation of operating actions was not possible for the user in the scenario. For example, employees were asked to use the controller to perform various operating actions, such as virtually switching the machine tool on and off, which very often failed. Eight out of ten test subjects were unable to cope with the controls and navigation within the virtual learning environment, which meant that the actual training was not carried out at the user's request. This conflicts with the fact that the prerequisite for the acceptance of a virtual learning scenario is, on the one hand, the existence of a high recognition value between the virtual learning environment and the real environment and, on the other hand, the success of the training must be ensured in every case.Based on the findings described for the virtual commissioning of a machine tool, the article presents the methodical development of a virtual learning scenario that focuses on maintenance tasks for a lathe. This includes the initial development and two stages of improvement.The usability of virtual training in the field of maintenance is to be evaluated and improved using this learning scenario as an example. The article therefore describes the technical tests carried out on the feasibility, improvement and acceptance of the test subjects and discusses questions of usability and learning success.