Georg Fischer Agie Charmilles DEMO

Georg Fischer Agie Charmilles (GFAC) is a manufacturer of high precision machine tools which use a metallic wire (electrode) to cut a programmed contour in a workpiece (wire EDM, Electric Discharge Machining). Current practice of WEDM is not defect-free and still a number parts produced by WEDM processes are rejected due to surface quality defects. The main defects related to surface quality of WEDMed parts include: occurrence of “lines” and “marks”, surface roughness, and recast layer (also called white layer). Within the IFaCOM project, a dedicated system has been developed and implemented on a GFAC machine (Cut 200 wire EDM machine). The implemented system tackles the elimination of critical surface defects that could arise at some points of the part and could reduce the fatigue resistance to levels not accepted for such applications. The system develops the IFACOM concept framework at three levels: • a real-time control of the vital process parameters This system relies on high-speed data acquisition and processing of relevant process parameters (current, voltage) and performs the diagnosis of surface defects by detecting abnormal variation of some signal features, like short circuits characteristics. For testing and setting up this system, several intermediate developments have been necessary for interfacing the machine controller with the IFaCOM system and performing high-speed data acquisition (MHz). Once the system has been proven efficient, a real integration has been performed including ad hoc software and hardware development for performing the high-speed process monitoring and control. • a second monitoring and e-tracking control system. This system has been developed within the project for detecting if any critical event has not been corrected by the real-time IFACOM control. In such a case, a machining report indicates the position where this event occurred, for further inspection or correction. The value of such parameters can be followed in real-time with respect to reference values associated with part quality and position on the machining path. • Long-term, off-line correction system This system, based on the application of the fuzzy logic approach of WP6, allows to optimise the process towards zero defect based on the level of detected errors at working conditions.