Professor, Chungnam National University
A Novel Magnetostrictive Inkjet Printhead for Very High Viscous Fluids
Young-Woo Park (1,*), Hong-Ju Kim (2), and Myounggyu D. Noh (1)
(1) Department of Mechatronics Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon34134, KOREA
(2) Graduate School, Department of Mechatronics Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon34134, KOREA
This paper presents the procedure to design a novel magnetostrictive inkjet printhead (MagJet) for very high viscous fluids, and the ejection characteristics of such fluids at room temperature. Two silicon oils, with a viscosity of 500 cPs and 1000 cPs, are used. To achieve such a target, a mathematical modeling for estimating the required ejection pressure, numerical simulation for validating the mathematical model, magnetic circuit analysis for designing MagJet, and finally experimentation for evaluating ejection characteristics of the experimental fluids. The required pressure is estimated to be 650 kPa for a fluid with a viscosity of 500 cPs, and 1300 kPa for a fluid with a viscosity of 1000 cPs, respectively. Simulation with ANSYS Fluent results in 1400 kPa for a fluid with a viscosity of 1000 cPs at the end of the nozzle. The two types of the magnetic circuits for MagJet are analyzed by using reluctance concept: one with a permanent magnet (PM), and the other without a PM. FEMM is utilized to estimate the magnetic flux density (B) and magnetic flux intensity (H) along the Terfenol-D rod. The estimated values of B and H without PM is 0.05 Tesla and 5000 A/m higher than those with PM. The magnetic circuit without PM is adopted for the design of a novel MagJet. Instead, a vacuum pressure pump must be used to control the meniscus at the end of the nozzle. The driving signal is unipolar, which has a rising time, a dwell time, and a falling time. The generated pressure with an adopted magnetic circuit is measured to be 2600 kPa at an amplitude of 1 A current. The experimental results show that the sound droplets are made successfully with two fluids. It can be concluded that MagJet can eject very high viscous fluids at room temperature.
Dr. Young-Woo Park has been a professor of Mechatronics Engineering Department at Chungnam National University in Korea since 1995. He received his M.S. and Ph.D. from Syracuse University in 1989 and from the Penn State University in 1994, and taught Iowa State University before joining Chungnam National University.
Chungnam National University, founded in 1952, is one of the top 5 national universities in Korea. The total number of students and alumni is approximately 22,000, and 200,000, respectively.