Slot die coating was developed as a result of the need for a more efficient and economical coating method. Increased production speeds; better machine and cross-direction control, and less waste are advantages seen over other coating methods. This leads to lower cost and better product quality. A slot die is a device that determines the coating width and the coating solution or slurry's distribution. It comprises of a body (Figure 1 )and a flow chamber (Figure 2). The body is manufactured from a specific type of material, usually stainless or chrome plated tool steel, compatible to the coating solution or slurry, stable under operating conditions, and capable of holding a specific temperature by electrical or liquid temperature control. It can incorporate a lip adjusting system to mechanically or automatically tune out cross-web variations due to evaporation or rheology changes during the production process. The flow chamber is comprised of an entrance, a manifold, a preland, a secondary manifold (optional), and a land. It is designed from a computer flow-modeling program using the fluid's rheology, anticipated pumping rate, desired application temperature, desired pressure, and residence time.
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