ON-MACHINE COORDINATE MEASUREMENTS IN MICRO EDM MILLING

Gianluca Tristo, Manuel Balcon, Simone Carmignato, Giuliano Bissacco, Enrico Savio

Abstract

In micro electrical discharge milling material is removed by electrical discharges while driving a cylindrical tool electrode along tool paths as in conventional milling operations from the workpiece and the tool electrode. Hence, to achieve high precision machining it is necessary to accurately adjust the tool-workpiece relative position implementing a tool wear compensation strategy, which has to be empirically calibrated for the specific machining conditions. The measurement of the material removed from both tool and workpiece is of paramount importance, since tool wear compensation and machining simulation rely on this information. On-machine volume measurements enable process parameters optimization and tool wear compensation strategy calibration based on self-learning procedures as well as the implementation of process monitoring algorithms. In commercially available electrical discharge machines electrical contacts between the tool and the workpiece electrodes are detected by sensing low voltage short-circuits. This capability can be exploited to set the workpiece coordinate system and to perform dimensional measurements of tool and workpiece, using the tool electrode similarly to the touch probe in a coordinate measuring machine. However, accurate and traceable measurements of volumes can be challenging and a metrological validation of the method is missing. In this work an investigation of the accuracy of the on-the-machine volume measurements in a micro electrical discharge milling setup is carried out and an evaluation of the error affecting on-machine measurements is provided.

Keywords

micro manufacturing, on-machine metrology, volume measurements

Download

IMEKO-TC14-2013-24.pdf

DOI

-

IMEKO TC

TC14 - Measurement of Geometrical Quantities

Back to the proceedings