Blow molded headliner

A method for making a headliner comprising a substrate configured to be mounted to a vehicle in a position at least partially covering a lower surface of a passenger compartment roof, the substrate comprising an upper substrate surface and a lower substrate surface disposed opposite the upper substrate surface and a substrate peripheral edge, the substrate comprising a moldable material, and a plurality of cavities formed into the substrate between the upper substrate surface and the lower substrate surface;

• the method including the steps of:
• providing a blow mold having first and second opposing wall surfaces contoured to complement the exterior contours of the headliner substrate to be formed, including a plurality of enlarged regions having outer boundaries corresponding to the plurality of cavities formed into the substrate;
• providing a molten parison into the blow mold between said first and second opposing wall surfaces, said molten parison being formed as a hollow tube with opposed walls;
• closing said blow mold around said tubular parison and expanding the molten parison with opposed walls into conforming contact with said first and second wall surfaces of the blow mold, and pinching together said opposed walls of said molten parison at a plurality of locations within said peripheral edge to form said outer boundaries of the plurality of enlarged regions into a headliner comprising a plurality of cavities;
• allowing the molten parison to harden;
• and
• removing the headliner substrate from the blow mold.