Assessment of Geometric Error for a CNC Vertical Milling Machine at No-Load Condition

CNC machine tools are used for a long time and high-frequency results in various types of machine components experiencing damage and wear. It makes deviations from the original positioning accuracy of the CNC machine tool occur. This paper is carried out to identify geometric errors that occur in the DMTG XD-40A CNC vertical milling machine by measuring at the no-load condition with a ballbar and laser interferometer to ensure optimal machine performance. The results of the measurement with a ballbar show that the measurement values met the assumption of normality and the values of circular deviation, radial deviation, bi-directional circular deviation, and mean bi-directional radial deviation in μm of the YZ plane are 9.822; 12.074; 31.944; and 11.972, while the ZX plane is 9.832; 16.899; 31.112; 17.192. The results of the measurement and analysis of the XY plane show that the type of deviation (error) that contributes greatly to circular error is scaling mismatch error with 15%. The results of the laser interferometer measurements are compared with ISO 10791-2:2001 and ISO 10791-4:1998, hence the geometric deviation conditions are obtained. The results of the no-load measurement give the recommendations for maintenance activities in the form of compensation values for machine parameters as well as recommendations for maintenance and repair activities on the machine’s linear guideway as a form of maintenance related to the geometric deviation conditions of the CNC DMTG XD-40A machine tool in the X-axis and Y-axis.