Injection molding is one of the most popular manufacturing methods for the cost-effective mass production of the plastic parts. Filling analysis of the molten polymer provides useful information to investigate the process conditions to ensure successful replication. To validate appropriate gate location for a NEEDLE COVER, flow fronts and flow stresses for four different gating options and three different design options are analyzed and compared to the field results. Based on the results, the optimum gate location for the minimum flow stresses and uniform fill patterns appears to be at gate 3. Thus it also provides minimum possibility of part warpage throughout PORT HOUSING and NEEDLE HOUSING. The results of analysis on the increased wall thickness, lower melt temperature, and longer injection time indicated that higher melt temperatures were recommended to achieve successful molding. Injecting the polymer at a longer time (1.2 second) leads to a significant increase in flow stresses throughout the part and the increase of wall thickness achieve successful replication of the parts.