To improve the thickness accuracy and uniformity of the micro-gravure coating process in MLCC ceramic film fabrication, the work aims to investigate the effect of doctor blade geometric parameters on coating quality. Appropriate boundary conditions were selected to simplify the two-dimensional Navier-Stokes equation, deriving the Reynolds equation for the slurry flow in the gap between the doctor blade and the micro-gravure roller. A geometric relationship between doctor blade parameters and coating thickness was established. With the Matlab platform and based on hydrodynamic, contact mechanical, and mass transfer theories, a CFD fluid-structure interaction simulation was conducted to analyze the flow behavior of the slurry in the blade-roller gap. The simulation results showed good agreement with the theoretical thickness model. It was found that the type of doctor blade, the minimum blade-roller gap, and the blade angle collectively affected coating quality. The comma doctor blade achieved optimal coating uniformity with the parameter combination of Smin=5 μm, R=30 mm, k=10 mm, while the beveled doctor blade attained the minimum coating thickness at Lmin=5 μm and β=0°. For the beveled doctor blade, increasing β and Lmin helps improve coating uniformity, but results in a thicker coating. For the comma doctor blade, increasing the minimum gap leads to an increase in coating thickness, increasing the minimum gap and the blade radius enhances coating uniformity, whereas increasing k causes a decline in uniformity. This study provides a technical reference for doctor blade selection and parameter optimization in high-performance film coating processes for MLCC.
Key words
MLCC /
fluid mechanics /
coating thickness /
Matlab
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