Various embodiments of a mold cavity structure of a transfer molding system are disclosed. The transfer molding system includes a first mold-forming structure and a second mold-forming structure. The second mold-forming structure includes a mold cavity. The mold cavity includes a gate region, a component region, and a vent region. The component region is configured to enclose an electrical component. A volume of the vent region is adjustable. The transfer molding system further includes an inlet port coupled to the gate region and configured to direct a flow of a molding compound into the mold cavity during an operation of the transfer molding system.