Multiple-axis synchronization evaluation for CNC machine tool based on sensorless measurement

Synchronization among the running shafts in a CNC machine tool is always suffered by the speed variation of the drive motor and the vibration of mechanical transmission components. Synchronization error may decrease the manufacturing accuracy. A novel method is proposed to evaluate the synchronization for the shafts by using the built-in sensors in this article, which can be considered as a sensorless evaluation method. The advantage of this method is that no extra sensors are required. At the same time, some advanced signal processing techniques are applied to analyze those signals to discover more information about the synchronization. Experiments are taken on two CNC grinding machines to study on the synchronization among the running shafts. Some spectrum analysis approaches are employed to evaluate the synchronization among the running shafts. The stability of the running process can be clearly described by using those methods. The synchronization error fluctuation is also obtained at the same time, which is of great help to improve the performance of the machine tool.