Abstract: A method of operating a multi-nozzle extruder in an additive manufacturing system enables support structure to be formed while an object is also being formed. The method includes opening more than one nozzle in the multi-nozzle extruder, and operating an actuator with a controller to move the multi-nozzle extruder along a path to form a first group of multiple parallel ribbons of support structure simultaneously with material extruded from the more than one open nozzle.

Abstract: An extruder has a valve assembly configured to move pins to open and close the nozzles in a multi-nozzle extruder head independently. The pins of the valve assembly that are driven by actuators into and out of engagement with nozzles in the extruder head are positioned within sleeves that extend between the valve assembly and the extruder head. A gap is provided between the extruder head and the end of the sleeves proximate the extruder head to enable thermoplastic material leaking from the extruder that contacts the pins to remain in a melted or plastic state so the thermoplastic material does not interfere with the movement of the pins.

Abstract: An additive manufacturing system and method for improving the certainty of removing or etching excess substrate from a stack of printed substrate slices to arrive at a 3D object. The approach includes printing a pseudo image as a shell layer around a desired object slice with less polymer (e.g., thermoplastic) material than the 3D object solid layer slice. This slows the etching process when this pseudo image is reached. The pseudo image may be printed to surround the object polymer image on a printed substrate sheet as a shell that provides notice during the excess substrate removal/cleaning process that the desired polymer image is nearby and extra care must be taken to avoid removal of the desired polymer image. The pseudo image may have a 3D patterned surface that can be recognized by a person doing the sandblasting or recognized automatically by an automated 3D object finisher.

Abstract: An additive manufacturing system includes a heater for converting a filament of extrusion material into thermoplastic material. The heater has a channel configured to change the cross-sectional shape of the filament to a cross-sectional shape that has a greater surface area than the surface area of the filament before the heater receives the filament. The channel of the heater can also be configured to drive the center portion of the filament toward the heated walls of the channel and to mix thermoplastic material in the channel while exposing the center portion of the filament to the heated wall of the channel.

Abstract: An additive manufacturing system has a controller configured to modify numerical control programming instructions to form interlocking structures that improve object structural integrity in the Z-direction. The interlocking structures are produced by forming one layer with swaths that are separated by gaps and another layer that is formed over the gaps to fill the gaps and lay over the swaths forming the gaps.

Abstract: A method of operating an extruder assembly in a three-dimensional object printer translates and rotates an extruder body having an extrusion slot to produce three-dimensional objects more quickly and with greater precision. The method also includes rotating and moving one or more shutter bodies with respect to the extrusion slot to form a continuous filament of material of various sizes and shapes.

Abstract: An additive manufacturing system has a plurality of manifolds in an extruder. Each manifold is connected to at least one nozzle of the extruder so the at least one nozzle extrudes thermoplastic material through a corresponding aperture in a faceplate mounted to the extruder. A plurality of valves is configured between each manifold and each nozzle connected to the manifold so the nozzles connected to a manifold extrude thermoplastic material from the manifold selectively. The faceplate is also configured for rotation about an axis perpendicular to the faceplate so different orientations of the nozzles and the apertures of the faceplate can be obtained. The different manifolds of the extruder enable a plurality of thermoplastic materials having different properties to be extruded simultaneously so the materials can join to one another while the materials are at an elevated temperature.

Abstract: An additive manufacturing system has a controller configured to modify numerical control programming instructions to form interlocking structures that improve object structural integrity in the Z-direction. The interlocking structures are produced by forming one layer with swaths that are separated by gaps and another layer that is formed over the gaps to fill the gaps and lay over the swaths forming the gaps.

Abstract: An additive manufacturing system has a controller configured to operate an actuator to move a multi-nozzle extruder in an XY plane and rotate the multi-nozzle extruder about an axis perpendicular to the XY plane while operating the multi-nozzle extruder to form swaths in the XY plane. The controller operates the actuator and the multi-nozzle extruder to keep the nozzles of the extruder within perimeters formed for an object and to vary the speed and rotation of the extruder while extruding material to form precise structures.

Abstract: An apparatus changes the temperature of thermoplastic material in an extruder head to reduce the time for producing an object. The apparatus includes a cooling device located near the one or more nozzles of the extruder head to change the temperature of the thermoplastic material extruded by the extruder head. The apparatus cools the thermoplastic material to enhance the formation of exterior object features. A heater can also be positioned near the nozzle zone to heat the thermoplastic material to reduce the time for raising the viscosity of the thermoplastic material for forming interior regions of the object.

Abstract: An additive manufacturing system opens the valves in an extruder needed to form a swath and operates an actuator to move the extruder through a transition region with those valves open to establish an amount of extrusion material between a faceplate of the extruder and a portion of an object being formed that is adequate for formation of a swath. The length of the transition region is determined with reference to a viscosity of the material being extruded and a speed at which the extruder is moved to form the swath. The transition region can be perpendicular to a path of the extruder to form the swath or aligned with the path of the extruder to form the swath.

Abstract: An extruder has a valve assembly configured to move pins to open and close the nozzles in a multi-nozzle extruder head independently. The pins of the valve assembly that are driven by actuators into and out of engagement with nozzles in the extruder head are positioned within sleeves that extend between the valve assembly and the extruder head. A gap is provided between the extruder head and the end of the sleeves proximate the extruder head to enable thermoplastic material leaking from the extruder that contacts the pins to remain in a melted or plastic state so the thermoplastic material does not interfere with the movement of the pins.

Abstract: A controller operates a first actuator to produce relative movement between a multi-nozzle extrusion printhead and a support member along a predetermined path for one layer of a three-dimensional printed object. The multi-nozzle extrusion printhead includes a housing with a chamber, a valve assembly having a plurality of passageways, and a planar member having a plurality of nozzles. The passageways of the valve assembly and the nozzles of the planar member are connected to one another in a one-to-one correspondence and valve members of the valve assembly are operated to open and close melted extruded material flow to the nozzles selectively and independently.

Abstract: An extruder has a valve assembly configured to move pins to open and close the nozzles in a multi-nozzle extruder head independently. The pins of the valve assembly that are driven by actuators into and out of engagement with nozzles in the extruder head are positioned within sleeves that extend between the valve assembly and the extruder head. A gap is provided between the extruder head and the end of the sleeves proximate the extruder head to enable thermoplastic material leaking from the extruder that contacts the pins to remain in a melted or plastic state so the thermoplastic material does not interfere with the movement of the pins.

Abstract: A method of operating an additive manufacturing system feeds solid extrusion material into a heater using a slip clutch coupled to an actuator of a mechanical driver to supply thermoplastic material into a manifold in an extruder head. The method sets a speed of the actuator so the actuator operates at a rotational speed that is slightly greater than the rotational speed of the mechanical mover. This method helps maintain the pressure of the thermoplastic material in the manifold of the extruder head in a predetermined range no matter how many nozzles are opened in the extruder head.

Abstract: An extruder head has an arrangement of multiple nozzles in the faceplate that avoids aligning the multiple nozzles at angular orientations from the 0°-180° axis and 90°-270° axis intersection at the center of the faceplate. The extruder head includes a housing having a faceplate with a plurality of nozzles that are equally spaced from one another when the nozzles are projected onto a first axis in a plane of the faceplate and the nozzles are equally spaced from one another when projected onto a second axis in the plane of the faceplate that is orthogonal to the first axis. Movement of the extruder head along any angular path from the intersection of the first axis and the second axis in the plane of the faceplate enables at least one nozzle in the plurality of nozzles to not be aligned with any other nozzle.

Abstract: An additive manufacturing system includes a heater for converting a filament of extrusion material into thermoplastic material. The heater has a channel configured to change the cross-sectional shape of the filament to a cross-sectional shape that has a greater surface area than the surface area of the filament before the heater receives the filament. The channel of the heater can also be configured to drive the center portion of the filament toward the heated walls of the channel and to mix thermoplastic material in the channel while exposing the center portion of the filament to the heated wall of the channel.

Abstract: An additive manufacturing system and method for improving the certainty of removing or etching excess substrate from a stack of printed substrate slices to arrive at a 3D object. The approach includes printing a pseudo image as a shell layer around a desired object slice with less polymer (e.g., thermoplastic) material than the 3D object solid layer slice. This slows the etching process when this pseudo image is reached. The pseudo image may be printed to surround the object polymer image on a printed substrate sheet as a shell that provides notice during the excess substrate removal/cleaning process that the desired polymer image is nearby and extra care must be taken to avoid removal of the desired polymer image. The pseudo image may have a 3D patterned surface that can be recognized by a person doing the sandblasting or recognized automatically by an automated 3D object finisher.

Abstract: An additive manufacturing system operates an actuator to move an extruder with reference to a selected first zig-zag pattern to sparsely fill an interior region of an object by extruding a swath of thermoplastic material that has straight portions connected by angled portions. After a first pass using the first zig-zag pattern is completed, a second zig-zag pattern is used to form a complementary swath that forms rigid structure with the first swath. Use of the two patterns is alternated to sparsely fill the interior region in multiple layers of the object until a predetermined distance from a solid fill structure or surface is detected. Transition patterns are then used to increase the density of the swaths in the interior region in the next successive layers of the object until the layer is reached where a solid fill surface is formed over the swaths formed using the transition patterns.

Abstract: An apparatus includes a heater for converting a filament of extrusion material into thermoplastic material. The heater has a channel configured to change the cross-sectional shape of the filament to a cross-sectional shape that has a greater surface area than the surface area of the filament before the heater receives the filament. The channel of the heater can also be configured to drive the center portion of the filament toward the heated walls of the channel and to mix thermoplastic material in the channel while exposing the center portion of the filament to the heated wall of the channel.