The gas injection point remains open in most cases, therefore the gas injection point should be located on non-visible surfaces, away from high mechnical loading, and in thick walled areas. In order to obtain a uniform distribution of the gas bubble throughout the entire molded part, it is important to plan the location of the gate and gas injection point. Otherwise, unwanted material accumulations may occur and it may not be possible to avoid when processing. These material accumulations can lead to sink marks, surface imperfections, and heavier parts. For gas-assist injection molding that is done in the mold, the gas injection point will generally be close to the gate, so that the gas travels in a similar direction to that of the melt. An exception to this rule would be the blow back technique or an overflow cavity near the gate that is opened by a valve.

It is not always possible to centrally locate the gas injection point. Consequently, it is preferred to locate the gas injection point at one end of the molded article in order to avoid the accumulation of material.