Geometric Error Assessment of CNC Turning Machine Tools with a Case Study on Gildemeister CTX 310 Eco

This paper studies the measurement and assessment of circular geometric errors on CNC lathes under loading and unloading conditions. Hence it could generate certain information about maintenance activities. The research method was conducted by measuring the machine tools’ angular geometric error using a ballbar following ISO 230-4:2005 and cutting tests referring to ISO 13041-6:2009. The angular geometric error status of the machine was determined by comparing the measurement result with standard tolerances according to ISO 10791-2:2001, ISO 10791-4:1998, and ISO 13041-4:2004. The object of this machine study is a Gildemeister CTX 310 Eco with travel axis of X, and Z, about 160 and 450 mm. The ballbar measurements were tested by measuring the position of the cylindrical test, flatness test, circular test, and modification workpiece test. Geometric error in the results of the modification workpiece test, flatness test, and circular test that ate the machine tools are still in tolerance in the no-load condition test and the in-load condition test. The measurement result value of the bidirectional circular deviation of the modification workpiece test, flatness test, and circular test is 15.24, 16.64, and 16.28 μm. But the geometric error of the cylindrical test is 24.748 μm, and it exceeds the tolerance in the load condition test. Based on the assessment, the recommended maintenance activities are inspecting and repairing the mechanical driving components, such as servo motors and couplings, ballscrews, and linear guideway components.