- The electrode feed head integrated the macro/micro feed axes, the piezoelectric (PZT) actuator, the dual clamps and the original taper-swinging mechanism (TSM), so the composite functions for wire electrode are achieved including the guider positioning, the servo feed, the inchworm feed H. Tong et al. / Precision Engineering 37 (2013) 213–221 221 for wear compensation, and the taper-swing movement. In addition, the pitch angle, the roll angle, and the focal distance of nozzles’ holes can be positioned by the structure design of the workpiece positioning mechanism.