| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 96 === Coating methods are widely used in the traditional, MEMS-related and semiconductor industry. In order to select the working parameters of the process correctly and simply, the study of the influences of related properties on the coating process becomes very important. This study is concentrated on the stripe coating transient process. The correlated properties of stripe coating are the velocity of moving plate, flow rate, viscosity and surface tension. For measuring the coating width and the contact angle between the fluid and moving plate, the CCD camera is used to record the images of the transient coating process. The interactions among inertia force, viscous force and surface tension is found to be the key factor from the experimental results.
According to the experiment, five stages are proposed to describe the phenomena of spreading including drop growing, spreading of contact, recoiling, spreading, and over spreading. Drop growing is due to fluid being absorbed in the cross section of spreading head until it contacts with the base plate. Flow rate and viscosity would influence the spreading of contact, especially viscosity. When the fluid recoils, the recoiling speed is affected by viscosity. Finally the coating width is controlled by the flow rate, viscosity and the surface tension. Large flow rate and small viscosity will easily lead to over spreading, whereas small flow rate and large viscosity will easily lead to stripe breaking. Those mean coating fails.
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