Abstract: A method of conditioning a fiberboard mat having upper and lower surfaces for molding it into a three dimensional object by making a first series of internally directed discontinuous incisions in the fiberboard mat upper and lower surfaces; making a second series of internally directed discontinuous incisions in areas of the fiber board mat upper and lower surfaces which contain the first series of incisions; and, desirably, with incisions of the second series being angled with respect to incisions of the first series.

Abstract: Apparatus for cutting discontinuous incisions into opposing surfaces of a fiberboard mat to condition it for molding into three dimensional panels, i.e. door panels, comprising a first pair of horizontal rollers comprising an upper roller and a lower roller with a gap between the two rollers; a second pair of horizontal rollers comprising an upper roller and a lower roller with a gap between the two rollers; the gaps defining a horizontal path along which a fiberboard can travel; each of the rollers having a multitude of sharp cutter blades capable of making discontinuous incisions in the adjoining surface of a fiberboard mat.