Insert molding is a process that involves inserting a metal or plastic part into a mold cavity and then injecting molten plastic around it. This creates a single piece that combines the strength and functionality of the insert with the shape and appearance of the plastic. To design an insert mold for optimal performance, you need to consider factors such as the type and size of the insert, the material compatibility, the mold design and layout, the injection parameters, and the cooling and ejection systems.