Prevention of void-based-irregularity formation in thin-wall, injection-molded plastic product

A method of injection-molding a product that includes at least one thin wall, comprising the steps of:

• (a) combining a plurality of mold parts to define a mold cavity for forming the product and at least one gate from which fluid plastic material may be injected into the mold cavity, wherein the mold cavity includes at least one thin-wall cavity section and at least two opposed flow chambers that adjoin opposite edges of the thin-wall cavity section for directing injected fluid plastic material from exit positions of the said at least two opposed flow chambers into corresponding entrance positions of the at least one thin-wall cavity section to thereby form at least one thin-wall portion of the product, wherein the at least one thin-wall cavity section includes at least one zone that is located between said at least two opposed flow chambers, and wherein within the at least one zone inscribed-sphere dimensions at each entrance position are smaller than inscribed-sphere dimensions at the corresponding exit position of the adjoining flow chamber;
• and
• (b) injecting fluid plastic material from the gate into the mold cavity to form the product;
• wherein step (a) comprises combining mold parts that define a said mold cavity in which within said at least one zone of the at least one thin-wall cavity section the thickness of the at least one thin-wall cavity section increases in the general direction of flow within the flow chambers adjoining said zone, with said increase being at less than a threshold rate to thereby prevent injected fluid plastic material so directed into the at least one zone from at any time surrounding any gaseous void within the at least one zone.