壓電式噴墨系統之液滴噴射行爲模擬

Simulation of the Droplet Ejection Process of a Piezoelectric Inkjet Printhead

吳鉉忠(H. C. Wu) ； 郭永吉(Y. C. Kuo) ； 林惠娟(H. J. Lin) ； 黃文星(W. S. Hwang)

《材料科學與工程》 35卷4期 (2003/12) Pp. 217-224

https://doi.org/10.6409/JMSE.200312.0217

摘要

壓電式噴墨系統中，藉由電壓驅動壓電材料產生變形，並擠壓墨水噴出液滴，因爲液滴飛行過程及液滴打擊至靶材均在微米尺寸下，所以表面張力與附著力的影響甚大。因此本研究將針對表面張力與附著力對於微液滴之影響來進行研究，探討在壓電式噴墨系統中液滴在飛行過程之形狀變化、主液滴與衛星液滴分離以及液滴和靶材間的潤濕效應之情形。由於液滴在飛行過程的形狀變化是一個兩相（空氣與墨滴）且曲率變化大的問題，爲了有效地模擬這些現象，採用VOF法來計算網格內兩相的體積變化，以PLIC法來界定液滴與空氣的界面。而在表面張力與附著力的處理上，則採用CSF數學模式，直接於動量方程式中考慮表面張力與附著力的影響；壓電材料的膨脹與收縮則是採用移動邊牆的方式處理。

關鍵字

壓電式噴墨 ； 電腦模擬 ； PLIC ； CSF

並列摘要

The ink droplet was ejected from nozzle because the deformation of piezo-diaphragm after an electrical pulse in the piezoelectric inkjet printhead. The effects of the surface tension and adhesion force on the formation of the droplet were very important and will be investigated in this study. The phenomena of break-off of the main droplets, satellite droplets from the ejected ink and the wetting effect between droplets and target were analyzed. In fluid dynamics, it is a problem involving a severely deforming free liquid surface interacting with a gaseous environment. A volume-of-fluid tracking method was applied to tracking the fluid domain and interface. A volume fraction function F governed by equation of conservation of volume was used to represent the fluid volume in each cell. The PLIC (piecewise Linear Interface Calculation) scheme was imposed to reconstruct the interface of droplet and air. The surface tension adhesion force were implemented by the CSF (continuous surface force) model. The phenomena of expansion and contraction of piezoelectric materials were treated by moving boundary method.

並列關鍵字

Piezoelectric Inkjet ； Computer simulation ； PLIC ； CSF