Cross layer fiber entanglement to increase strength of 3d part

A method for entangling stacked printed fibrous sheets from an additive manufacturing system, comprising:

• placing a printed fibrous sheet on top of another printed fibrous sheet to form the stack of printed fibrous sheets on a bed plate, each printed fibrous sheet patterned for a slice of a desired 3D object and including a registration aperture, at least one of the printed sheets having fibers therein, the placing the printed fibrous sheet including aligning the printed fibrous sheet with the another printed fibrous sheet via a registration pin aligned with the bed plate and extending through the registration aperture of the printed fibrous sheet;
• applying pressure to the stack of printed fibrous sheets with a guide plate in a first position pressed against the stack of printed fibrous sheets, the guide plate having an array of apertures extending vertically there through;
• reciprocating an array of felting needles held by a needle board and extending towards the bed plate through the guide plate array of apertures and a plurality of the printed fibrous sheets adjacent the guide plate, the reciprocating including inserting the felting needles through the array of apertures when the guide plate is in the first position and further inserting the felting needles through a plurality of the printed fibrous sheets adjacent the guide plate, the reciprocating further including withdrawing the felting needles out of the stack of printed fibrous sheets, the felting needles having a barb configured to intertwine fibers from one of the plurality of printed fibrous sheets of the stack through printed marking material on the printed fibrous sheets and with fibers of a neighboring printed fibrous sheet of the stack during the reciprocating.

A stacker subsystem of an additive manufacturing system, comprising:

• a punch holder aligned with a die holder, the punch holder configured to reciprocate towards and away from the die holder in a direction transverse to a delivery path for the printed substrate web fed between the punch holder and the die holder, the punch holder having a cavity therein with a cavity opening adjacent the die holder, the die holder having a channel there through corresponding with the cavity of the punch holder, the punch holder and the die holder configured to receive the printed substrate web there between, the printed substrate web including a plurality of printed fibrous sheets, each printed fibrous sheet patterned for a slice of a desired 3D object and including a registration aperture, at least one of the printed sheets having fibers therein;
• a punch plate slidingly received within the cavity in a peripherally spaced relation, the punch plate configured to reciprocate in the direction transverse to the delivery path of the printed substrate web between a recessed position in the punch holder and a cutting position extended into the channel of the die holder to sever a substrate sheet from the printed substrate web, the punch plate having an inner periphery wall defining an aperture;
• a bed plate configured to support a stack of the severed printed fibrous sheets;
• a registration pin aligned with the bed plate and extending through the registration aperture to maintain the severed printed fibrous sheets of the stack in alignment on the bed plate;
• a guide plate aligned with the bed plate and having an array of apertures extending vertically there through, the guide plate configured to reciprocate towards the bed plate to a first position urging the severed printed fibrous sheet against the stack of severed printed fibrous sheets, and away from the bed plate to a second position that allows placement of an additional severed printed fibrous sheet onto the stack;
• a needle board adjacent the guide plate opposite the bed plate;
• and
• an array of felting needles held by the needle board and extending towards the bed plate with the array of felting needles in alignment with the guide plate array of apertures, the felting needles being disposed for reciprocation through a plurality of the printed fibrous sheets adjacent the guide plate via insertion through the array of apertures when the guide plate is in the first position, and further for insertion through the plurality of the printed fibrous sheets adjacent the guide plate, the felting needles having a barb on a peripheral surface thereof configured to intertwine fibers from one of the plurality of printed fibrous sheets of the stack through printed marking material on the printed fibrous sheets and with fibers of a neighboring printed fibrous sheet of the stack.