Three dimensional fiber deposited multi-layered/multi-blend molded fiber parts

A method for manufacturing a net shape molded fibrous part that avoids the use of expanded polymeric foam pads comprising:

• (a) providing first and second tool portions of a mold for shaping a fibrous part, the first tool portion having a molding surface and including perforations along all or a portion of the molding surface;
• (b) introducing fiber and binder from one or more robotic fiber injectors to one or a plurality of first selected areas of the molding surface and providing vacuum to said one or a plurality of first selected areas, wherein the one or a plurality of first selected areas are each smaller than an entire area of the molding surface and have a dimension ranging from 7.62 cm×12.7 cm to 45.7 cm×45.7 cm;
• (c) with a fiber delivery apparatus, introducing fiber to the entirety of said molding surface simultaneously, or introducing fiber on top of any fiber that was previously deposited to simultaneously form an entire layer on an entire surface of said fiber that was previously deposited and on any exposed portion of said molding surface;
• (d) determining that a selected fiber loading level is present in said one or plurality of first selected areas;
• (e) closing the first and second tool portions and heating with heated air to form a fiber part that has a first density in said one or a plurality of first selected areas and a second density in one or a plurality of second selected areas, wherein the first density is higher than the second density;
• and
• (f) forming said net shape molded fibrous part by removing 0 to 10 weight % of the fiber part, the net shape molded fibrous part configured to be installed directly into a vehicle 1 wherein:
• the net shape molded fibrous part is a vehicular panel that comprises a first acoustic layer and a stiff fiber layer on or below the first acoustic layer;
• the first acoustic layer has a stiffness (K) in a range of 0.1 to 5500 newtons/meter (N/m) and an absorption coefficient in a range of 0.4 to 1.0 at frequencies greater than or equal to 500 Hertz (Hz);
• the stiff fiber layer has a stiffness (K) in a range of 5501 to 1,000,000 N/m;
• and
• K=F/d, where F is force in newtons applied over an area of 0.0014062 m2 in the middle of a 0.09 m2 square sample of the first acoustic layer or the stiff fiber layer, respectively, and d is the displacement in meters of the sample in the direction of the applied force.