Material selection is an important step under active planning phase in production planning and control and, so is process selection. Polymers are preferable option for various products due to their desirable properties. Light weight, low cost, corrosion resistant and high strength to weight ratio is few among them. In similar manner injection molding is the most suitable process to be preferred for processing various grades of thermoplastics. The process preferably utilizes a heating unit to take polymers to their injection temperature, a permanent mold with shaped cavity as the shape of the required product along with clamping and cooling provisions. The process is best suitable for mass production of plastic parts and is widely used industrially. The permanent mold used in injection molding process is also referred as plastic mold. These molds must be designed and analyzed before their manufacturing to ensure suitability of the molding with particular plastic material type. This article attempts to ensure suitability of molding plastic wing nuts, an internal threaded component, by injection molding process with polypropylene (PP) and high density poly ethylene (HDPE) material. Modeling of parts is done with UG Nx 9.0 while the flow analysis is performed by Autodesk Mold Flow Adviser 2015.