Abstract: Disclosed are a method and apparatus for matching the extrusion rate of a liquifier which extrudes a flow of material to a predetermined target output rate. The present invention adjusts the volumetric rate of material going in to the liquifier to account for a predicted melt flow component of material being extruded from the liquifier. Compensating for the predicted melt flow results in reduced error in an extrusion profile produced by material deposited along a toolpath followed by the liquifier.

Abstract: Disclosed is a modeling filament for use as feedstock in a fused deposition modeling liquifier, and a method for manufacturing the filament. The diameter and standard deviation of the filament are controlled to meet various tolerance requirements of jam resistance, slip resistance, model strength, liquifier overflow prevention and hysteresis-free transient response. Standard deviation of the filament diameter is matched to a filament target diameter. The resulting filament is used to form high-quality models.

Abstract: An apparatus has an extrusion head for extruding a bead of a liquified material at an extruded pump flow rate, an extrusion head motor for driving the extrusion head at a variable head velocity, a pump for providing liquified material to the extrusion head, and a control for providing control signals to both the extrusion head motor and the pump. The control signals control operation of the extrusion head and the pump so that the head velocity is slaved to an estimated profile of the extruded pump flow rate divided by a predetermined bead cross-sectional area.

Abstract: The present invention provides a method for controlling following error in a robotic system that moves a tool at a velocity along a path defined by an inputted set of vertices. The following error is controlled to be less than a tolerable error allowance. First, a subset of resonant vertices is identified from the inputted set of vertices. Each of the resonant vertices has a neighboring vertex for which a following error that results when the tool negotiates both the vertex and its neighboring vertex at an assigned vertex velocity might exceed the tolerable error allowance. Second, each vertex in the subset of resonant vertices is assigned a reduced vertex velocity. The reduced vertex velocity is selected so that the following error that results when the tool negotiates both the vertex and its neighboring vertex at the reduced velocities is less than the tolerable error allowance.

Abstract: Processes and apparatus are disclosed for producing three-dimensional objects having overhanging portions freely suspended in space without any material of the object in direct, supporting engagement therewith in the final geometry of the object. A support structure is formed by depositing material which will be under the ultimately suspended portions of the object to be formed, during a process in which material is built up in layers to form the object as well as the underlying support structure. A readily removable support structure is formed along an interface with the underside of the suspended portion of the object structure. A weak, removable or breakable joint is formed along that interface by the use of an interface material which forms a weak or dissolvable bond with the material of the object. The release material may be deposited as a separation layer, or as a thin coating.