A protective helmet and method and apparatus for makingthe same. The helmet is made of an expanded resilient polymerand configured with an undercut portion and with holes forventilation and/or the mounting of a helmet retention system.The holes are generally perpendicular to the surface of thehelmet at the hole. The mold (110) for making the helmetincludes a core (112) and a cavity (114). The cavity isconfigured with projections (116, 118) for molding holes in theback of the helmet and the core is configured with projections(120, 122) for molding holes in the front of the helmet. Thespace between the core and the cavity when in an engaged positiondefines the shape of the helmet, including any desired undercutportions. The helmet is molded by injecting compressed,resilient polymeric beads into the mold, venting the mold whileapplying heat to expand the beads, permitting the mold to cooland retracting the cavity from the core along a line ofretraction to release the part from the mold.
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