Development of a Stress Factor as an Indicator for Stress-Based Payment Models for Machine Tools

Pay-per-use models for machine tools based on the operating hours neither include the load nor the actual wear of components, although the machining process has a strong impact on the wear of components and consequently on the residual value of the machine tool. This requires a characteristic indicator for the implementation of stress-based data driven payment models for machine tools, which correlates with the degradation process during operation. Also, the indicator has to be responsive from the beginning of the lifecycle of a component and not from the point where a significant change of the condition or potential failure is detected. Therefore, this paper presents an approach to determine the degradation of a machine tool based on the calculation of the wear reserve for most relevant components. Since data driven modeling of the degradation process demands an enormous amount of data, this approach considers the fatigue theory and the calculated life including the actual load during the machining process. This concept provides transparency in the usage of machine tools and allows to implement a stress-based payment model.