A process variability analysis is carried out to find the most influencing input parameter and corresponding output parameter variation using the L9 approach. The common factors, levels, parameters, and responses are mentioned in the following section. The mean response curve for the output parameters is also presented. Empirical relations are obtained for finding the responses in terms of the common factors. EBX936 (Non-Crimp bidirectional, Glass Reinforcement Manufactured by-Tech. Textile, USA) with 3, 6, 12 number of layer (NOL) is the material system used in the analysis. The infusion pressure is kept in the workable range of 60 to 70 kPa as normally used in the VARTM process. Very high vacuum at inlet increases the resin velocity through the preform and hence the time of infusion will reduce drastically, giving very little time for proper saturation of fibers in the preform. Therefore, to keep the velocity in the middle range of velocities during the infusion low injection pressures are selected. The viscosity of the resin is selected in the range 0.2 to 0.3 Pa.s.