An inkjet printer comprises an array of nozzles extending substantially a width of a print media fed through the inkjet printer; and a plurality of heater elements each corresponding to a nozzle, the heater elements being formed substantially of titanium nitride. The measurement invocation system is configured to provide graphical control elements on the graphical user interface such that the selection of a control element invokes a measurement operation on a selected displayed waveform. A weld joint is provided having a joint groove with a lower face formed by a stepped end preparation, such as that of the first work piece, and an upper face formed by a beveled end preparation, such as that of the second work piece. The unipolar oscillating voltage may have only positive or only negative voltages between the electrode and the perforated plate.