Abstract: A system for molding a part including a first surface and a second surface opposing the first surface, the system includes: a pressure supply arrangement; and a Reaction Injection Molding (RIM) arrangement including a pin plate assembly and a mold defining a mold cavity, the RIM arrangement configured for supplying a bi-component liquid mixture to the mold cavity in which the bi-component liquid mixture chemically reacts and thereby forms a thermoset polymer, the pin plate assembly coupled with the pressure supply arrangement and the mold, the pressure supply arrangement configured for supplying an inert gas to the mold cavity via the pin plate assembly and thereby for one of reducing and eliminating a formation of a sink mark on the first surface of the part.