Numerical Studies of Flow Dynamics in a Piezoelectric Inkjet Printhead

• Main Authors: Tsong-Yi Lin, 林聰鎰
• Other Authors: Tzong-Shyng Leu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/20347074451338643917

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 95 === Micro-droplet injection technology, originated from inkjet printing technology have been applied to many appilications such as IC package, LCD color filters, micro fuel pump, 3D rapid prototyping technology, and bio-medical devices. Accompanying with progress of Micro Electro-Mechanical Systems (MEMS), piezoelectric inkjet printhead, one of the major technology of Drop-on-Demand (DOD) inkjet printheads, has raised a lot of attention because of its great ability to wide applications. This thesis studies the squeeze mode piezoelectric inkjet printhead by the method of simulation. In this study, the numerical methods are used to solve continuity and momentum equilibrium equations for flow field , as well as VOF (Volume of Fluid) and PLIC (Piecewise Linear Interface Calculation) schemes for the free surface construction. For the treatment of surface tension effects, a CSF (Continuum Surface Force) model is employed. In this study, a moving boundary is used to express the deformation boundary conditions of a squeeze-mode piezoelectric inkjet printhead while driven by sinusoidal AC signal. The main objectives for this study is using different parameters including printhead geometry and opearation conditions to find out the influence of parameters on the dynamic behaviors inside the inkjet printhead after the vanishment of transient behavior. In this study, it is found that the velocity and pressure will be raised by the increase of the tube length, frequency and amplitude, or reduced the radius of tube and orifice. The change of maximum velocity in the device is found to be proportional to frequency and amplitude. It is noticed the maximum pressure in the device becomes linear with respect to the amplitude, and the square of frequency. The increase or decrease of frequency can also change the ejective droplet volume. Theses findings will help designers not only in the design a piezoelectric inkjet printhead, but also in control of the droplet size ejected from the piezoelectric inkjet printhead.