Methods, apparatus, and systems for cutting material used in fused deposition modeling systems are provided, which comprise a ribbon including one or more perforations. Material is passed through at least one perforation and movement of the ribbon cuts the material. A further embodiment comprises a disk including one or more blade structures, each forming at least one cavity. Material is passed through at least one cavity and a rotational movement of the disk cuts the material. A further embodiment comprises a slider-crank mechanism including a slider coupled to a set of parallel rails of a guide shaft. The slider moves along a length of the rails to cut the material. Yet another embodiment comprises one or more rotatable blade structures coupled to at least one rod. The rotation of the blade structures causes the blade structures to intersect and cut extruded material during each rotation.

A print assembly 18 for use in an additive manufacturing system 10 to print three-dimensional parts 12, which includes a coarse positioner 40, a fine positioner 42, and a liquefier assembly 20, where a portion of the liquefier assembly 20 is operably mounted to the fine positioner 42 such that the fine positioner 42 is configured to move the portion of the liquefier assembly 20 relative to the coarse positioner 40.

This invention involves a new and better solution to the problems associated with the premature softening of PLA filaments in the additive manufacturing of three dimensional articles. It is based upon the finding that poly(lactic acid) filaments with high crystallinity offer much better resistance to heat-induced softening. The crystalline poly(lactic acid) filament of this invention can accordingly be used in the additive manufacturing of three dimensional articles without encountering the problems associated with premature softening, such as poor quality and printer jamming. The crystalline poly(lactic acid) filaments of this invention can also be used in additive manufacturing of three dimensional articles without compromising the quality of the ultimate product, reducing printing speed, increasing cost, or leading to increased printer complexity. This invention more specifically discloses a filament for use in three-dimensional printing which is comprised of crystallized poly(lactic acid), wherein said filament has a diameter which is within the range of 1.65 mm to 1.85 mm.

A polypropylene comprising within a range from 0.1 wt % to 4 wt % ethylene and/or C4 to C12 -olefin derived units, one or more clarifiers, or both; wherein the polypropylene has a flexural modulus of at least 200 kpsi (0.05 in/min ASTM D790(A)) and an Mz/Mw of at least 4. The polypropylenes may be made by combining propylene and a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein the concentration of the electron donors is within a range from 1 to 100 ppm. The concentration of electron donors may be decreased to control the haze level of the polypropylene, and/or the level of comonomer derived units may be controlled to reduce the haze level of the polypropylene.

A method of manufacturing bulked continuous carpet filament from recycled polymer. In various embodiments, the method includes: (1) reducing recycled polymer material into polymer flakes; (2) cleansing the polymer flakes; (3) melting the flakes into a polymer melt; (4) removing water and contaminants from the polymer melt by dividing the polymer melt into a plurality of polymer streams and exposing those streams to pressures below 25 millibars or another predetermined pressure; (5) recombining the streams; and (6) using the resulting purified polymer to produce bulked continuous carpet filament.

An extruder is fitted with a connector for coupling and decoupling with a filament feed source, such as a filament tube. When connected, the extruder and filament tube are aligned to define a feed path for a filament. A tool rack includes a plurality of filament tubes secured within respective openings. The tool rack may facilitate coupling and decoupling operations between the extruder and filament sources. For example, the tool rack may define an insertion path that engages a filament tube during insertion, and that secures the filament tube against an excursion from the insertion path. The extruder may disengage the coupling by initiating a motion along the insertion path and then moving off of the insertion path to decouple the filament tube and the extruder. In this manner, filaments may be swapped through engaging and disengaging the extruder with different filament tubes on the tool rack.

A method for production of a molded part made of plastic by rotational molding includes placing a starting material in a form of at least one of a plastic or a plastic precursor into a rotational melt mold that is fitted with at least one magnetic element. The rotational melt mold is rotated and, while the rotational melt mold is rotating, the starting material is shaped. The at least one magnetic element rotates together with the rotational melt mold while the starting material is being shaped. The starting material and the at least one magnetic element are configured in such a way that the starting material and the at least one magnetic element interact magnetically such that a portion of the starting material is attracted and held in place by the at least one magnetic element while the starting material is being shaped.

A print assembly for use in an additive manufacturing system to print three-dimensional parts, which includes a coarse positioner, a fine positioner, and a liquefier assembly, where a portion of the liquefier assembly is operably mounted to the fine positioner such that the fine positioner is configured to move the portion of the liquefier assembly relative to the coarse positioner.

A method for manufacturing bulked continuous carpet filament, the method comprising: (1) reducing a chamber pressure within a chamber to below about 5 millibars; (2) after reducing the chamber pressure to below about 5 millibars, providing a polymer melt to the chamber; (3) separating the polymer melt into at least eight streams; (4) while the at least eight streams of the polymer melt are within the chamber, exposing the at least eight streams of the polymer melt to the chamber pressure of below about 5 millibars; (5) after exposing the at least eight streams of the polymer melt to the chamber pressure of below about 5 millibars, recombining the at least eight streams into a single polymer stream; and (6) forming polymer from the single polymer stream into bulked continuous carpet filament.

A nozzle assembly for an injection molding system has a nozzle adapter with one or more vent holes therein. A porous metal insert is provided in fluid communication with at least one of the vent holes. The porous metal insert is also in fluid communication with a flow channel through the nozzle assembly. As molten polymeric material advances through the flow channel from a barrel to a mold assembly, gases entrained in the molten polymeric material are vented through the porous metal insert and escape through the one or more vent holes. Pressurized air may be introduced through the vent holes, such as by one or more blow-back modules, to unclog pores of the one or more porous metal inserts between shots of the injection molding system.