Development of magnetostrictive inkjet head for liquid droplet formation

This paper presents the development of Magnetostrictive inkjet head (MAG-Jet), which consists of a Terfenol-D actuator, a chamber connected to a fluid reservoir through a fluid inlet, and a glass nozzle. The functional requirement for the MAG-Jet is that the droplet must exit the nozzle at a speed of 5 m/s. The diameters of the chamber and nozzle are set to 1.0 mm and 100 μm, respectively. To achieve the functional requirement of the initial settings, a fluid dynamic model is developed for estimating the required force per unit area exerted by the Terfenol-D actuator. Then, a mathematical model of the magnetic circuit for the actuator is developed in terms of magnetic flux and reluctance, and this is followed by a finite element analysis using a commercial program. The developed MAG-Jet is used to evaluate the performance. The input current of all the experiments is set as ± 1.8 A and the bipolar waveform is selected as the basic driving waveform. Also, the optimal process is ensured to determine the time values for the driving waveform. The designed driving waveform applied to the MAG-Jet has the inflow time of 370 μs, ejection time of 10 μs, holding time of 360 μs, and breakup time of 10 μs. Successful droplet formation is made by using the developed MAG-Jet.