Measurement and prediction of thermal errors of a CNC machining center using two spherical balls

Abstract

This paper proposes a method of measuring the geometric and thermal errors that occur with a temperature change of a CNC machining center by means of on-machine measurement using two spherical balls and a touch probe unit. A neural-network model is used to predict the thermal errors of machine tools whilst machining workpiece, the model being modified based on the results of the measurement of two balls to raise reliability in the error prediction. The experiments show that the proposed method provides good results in error measurement and prediction. The proposed measurement system can be installed on machine tools and used for measurement without any interruption of production.