Forming belt for three-dimensional forming applications

A method and apparatus for forming a layer structure, such as an airlaid fibrous web, include a supplying mechanism for providing a stream of particulate material, such as fibers. Also included is a substantially endless, foraminous forming belt which has an appointed outward surface and a minimum thickness of at least about 3/16 inch. A selected contour is formed into the outward surface of the belt at selected locations, and the contour is distributed along a lengthwise machine-direction of the forming belt. The forming belt is configured to flex along a thickness direction thereof, and to recoverably bend and substantially straighten when traveling along a selected belt path circuit. A conveying mechanism moves the forming belt past the supplying mechanism along a forming path section of the belt circuit which is substantially straight, and moves the forming belt along a return path section of the belt circuit which includes curved portions therein. A vacuum mechanism draws a flow of air through the thickness of the forming belt to lay the particulate material onto the forming belt to form a layer structure, such as a web, having a top surface and a belt-side surface thereon. The web is thereby produced with a selected non-uniform thickness contour which is formed along the belt-side surface of the fibrous web. A driving mechanism moves the forming belt along the machine-direction at a selected speed, and a transporting mechanism removes the contoured web from the forming belt.