Experimental study of operational data collection from CNC machine tools for advanced analysis

The purpose of this paper is to present a method of data acquisition and monitoring of a CNC machine tool in the manufacturing process to assess the suitability of the CNC machine tool as a measurement device. The presented method is based on a developed data acquisition system that uses the machine control system itself and an additional platform for measuring operational variables outside the machine control system. Information on motor currents, motor speeds and temperatures are read from the machine control system using the OPC UA protocol. The additional operating variable measurement platform includes an independent IPC with server application and database on the upper layer, to which the NI cRIO DAQ unit is connected on the lower layer with a connection to the temperature measuring terminals via EtherCAT bus. Individual resistance thermometers are further positioned at significant positions on the machine to detect dominant dependencies of machine operation on ambient temperature. The presented data acquisition system was verified in a workshop environment on a three-axis CNC machining centre with a Siemens Sinumerik 840Dsl control system to demonstrate its functionality leading to a positive assessment of the CNC machine tool’s suitability as a measurement device.