Design of a Test Part for Verification and Validation of a Three Linear Axes Machine Tool

Abstract

On traditional manufacturing systems such as machine tools (MTs), the increase on their operational capacity goes hand in hand with the improvement of its efficiency and accuracy. To do that, there are two types of verification methods, direct and indirect methods. The main aim of this job is to develop a test part to machine that allows determine the influence of the geometric errors of a three linear axes MT using volumetric and geometric methods. When the test part is machined, all axes of the machine are moved simultaneously. So, the difference between machined and test part design are, among others, the results of MT geometric errors. These errors can be reduced using volumetric verification techniques and MT compensation. Moreover, a proper test part design provides a work piece than can be used as a reference artefact for MT calibration. Nominal data of the test part can be obtained using a coordinate measurement machine. So, if the MT measures the machined test part using a probe, the difference between real and nominal coordinates could be used to obtain MT geometric errors. Therefore, the test part has to be designed to allow an easy data capture of the MT; taking into consideration the different kinematic models used to improve its accuracy. The new test part developed consist of a rectangular block with grooves and battlements on its external faces and an internal pyramidal structure. In addition, a series of conical holes are strategically located along the surface to improve data capture and errors identification. Synthetic tests show that this test-part design provides good results using volumetric and geometric techniques.