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Multi-axis electrical discharging machining (EDM) is the main manufacture method for shrouded blisks, which are key components of aero and rocket engines. Involving both linear and rotational axes, a feeding path for machining a narrow and twisted channel consists of a large number of G-code lines. Accelerations and decelerations at junctions, which connect two neighboring G-code lines, can significantly reduce the machining efficiency. In this paper, a new simplification of feeding paths in roughing EDM for shrouded blisks is proposed in order to reduce the number of junctions on a feeding path. However, deviating from the original feeding path, a simplified feeding path can bring over contour errors which can cause geometrical errors of workpieces. Contour error can thus serve as a criterion for simplifying the original path. Eight vertices of a hexahedron, which contains the electrode, are used to represent all points inside and on an electrode. Forward kinematics of a six-axis EDM machine is used to calculate the contour errors of the eight vertices when the electrode feeds along a simplified path. A simplified feeding path can be found provided that the contour error constraint is respected. Machining tests show that the use of a simplified feeding path in roughing EDM machining can reduce the average total machining time by 26.5% without significant impact on surface roughness and white layer thickness. [ABSTRACT FROM AUTHOR]

Owing to the contaminations in the small discharge gap of micro-electro-discharge machining (µEDM), generation of nonuniform nature of discharge pulses is more significant than in macro-EDM. To address the contribution in material removal of workpiece by each of these pulses, a pulse discriminating (PD) system which discriminates them into contributing and noncontributing types is generally used. Developing a PD system in µEDM is a time-consuming process that requires an availability of continuously running machine. Such requirement could be eliminated if virtual signals, similar to the actual once, are made available and provided continuously to the PD system developer. An innovative idea of generating such virtual signals, based on ni multisim, is, therefore, proposed and a robust PD system based on these signals is developed and validated. The strategy for discriminating the pulses in various types is developed through virtual instrumentation in ni labview. The robustness is validated in terms of its applicability over a wide range of parametric settings, acquisition length, and time. [ABSTRACT FROM AUTHOR]