Analysis of spatial and temporal dependencies of the TCP-dislocation measurement for the assessment of the thermo-elastic behavior of 3-axis machine tools
It is common to investigate the thermo-elastic behavior of machine tools by measuring the 3D-dislocation of the Tool Center Point (TCP) under several loading conditions. According to the ISO 230-3 standard, this can be achieved with extensive measurement procedures and expensive equipment (e.g. invar steel for the test mandrel). Based on the investigation framework stipulated by this standard and the R-Test measuring equipment, a novel method is applied that enables a holistic investigation of the thermal effects in an automated manner. This method automates the setup of the measuring instrument and simplifies the measurement in different positions in the workspace. The investigation of temporal and spatial dependencies of the TCP-dislocation is carried out on a 3-axis machine tool. Additionally, various loading modes are applied in accordance to the aforementioned standard. The strong influence of the tool position in the working space leads to the conclusion that zero offset and distortion are two different error types that should be discriminated from each other. This error separation enables a holistic as well as more intuitive understanding of the thermal effects on the machine tool. The possible sources of thermal-induced errors could thus be deduced for the investigated 3-axis machine tool and lead to anticipated conclusions for the particular construction.