Gate placement is often treated as a manufacturing decision, but it can have a direct impact on how a molded component performs in the real world. A gate may look perfectly acceptable in CAD and may even simplify tooling or filling, yet its location influences material flow, local orientation, cooling behavior, and the condition of the part after the gate is removed. When that location coincides with a highly stressed region, a seemingly minor design decision can become the starting point for premature failure.
One concern is the scar and local geometry left behind after gate removal. Depending on the material, process, and finishing method, this area can behave differently from the surrounding surface. If it sits near a thin wall, sharp transition, attachment feature, or another region subjected to repeated loading, local stresses may become concentrated around it. Under cyclic use, that concentration can contribute to crack initiation even when the nominal stresses predicted for the overall component appear acceptable.
This is why gate location should be considered alongside structural requirements rather than selected solely for CAD convenience. Whenever possible, gates should be moved toward thicker, lower-stress sections where the surrounding geometry can better tolerate the local effects of the molding process. Designers should also consider how material will travel from the gate through the cavity, where flow fronts will meet, and whether those conditions introduce additional weak regions in areas that carry significant loads.
Flow simulation and FEA can help connect these manufacturing and structural considerations before tooling is finalized. Flow analysis provides insight into filling behavior and potential process-related concerns, while structural analysis identifies the areas expected to experience the highest loads. Reviewing both together allows the team to make a much more informed gate-placement decision. The objective is not simply to produce a part that fills successfully, but one whose manufacturing strategy supports its long-term mechanical performance.