The characterisation of the dimensional change of the Z-axis in NC turning

Manufacturing high value-added parts often requires a considerable amount of time spent on machining, during which the machine’s dimensional characteristics may change. During this study, we endeavoured to characterise the dimensional change of the slideways and ball screw spindle of the Z-axis on an NC lathe. Indeed, such changes are harmful when it comes to obtaining precise dimensions along the Z direction of the lathe. Firstly, we specified the context in which the study was to be conducted and the problem we were confronted with. We then conducted an experimental study to highlight the parameters having an influence on the dimensional changes of the Z-axis. We then implemented modelling to generate a prediction model for this axis’s behaviour during machining. We were thus able to compensate for such errors by inserting programmed offsets, calculated from the prediction model [1]. We rounded off our study by milling a series of parts using a corrected NC programme that included a compensation for the dimensional change of the Z-axis in order to validate our approach.