In this study, we conduct computer simulations using smoothed particle hydrodynamics (SPH). SPH is a particle based meshfree algorithm based on Lagrangian formulation. SPH was first developed to solve the Navier-Stokes equations in the context of astrophysical fluid dynamics. Since its introduction, SPH has been successfully used to model a wide range of science and engineering problems. Compared to mesh based numerical methods, SPH eases the difficulty of dealing with complex geometry and deformable boundary and can model the interaction between fluid and solid structure in a straightforward manner. Using SPH, we model the injection molding process allowing for slip at the wall. Simulation results are compared with molding using molds coated with carbide bonded graphene network developed in our laboratory. We investigate the slip wall effect on the detailed fluid dynamics and heat transfer. In SPH, the slip effect on the wall is realized intrinsically through the interaction forces between the fluid and solid wall particles. Furthermore, we study the glass fiber orientation during the injection molding process, especially close to the flow front where the fountain flow plays a major role.