Capillary filling, the autonomous wicking of liquids through hydrophilic microchannels driven by surface tension and wettability, enables pump-free, precise fluid handling in microfluidic devices for the biotechnology, MedTech, semiconductor, and chemical processing fields. In this case study, we present advanced simulations of capillary filling and its dependence on wettability, quantified by the contact angle. Such simulations inform product and process design decisions to enhance efficiency, reliability, and scalability.