Disclosed are embodiments of a three-dimensional (3D) printer for building 3D objects with layer based, additive manufacturing techniques. The hot end can be moved in a horizontal plane parallel a planar printing surface of the printing bed while the printing bed can be moved perpendicular to the planar printing surface to print a 3D object. The hot end can be part of an extrusion guide assembly. The 3D printer can auto-level the printing bed.

Methods have been discovered that make it possible to continuously extrude tubes of P4HB and copolymers thereof. These methods allow tubes of P4HB and copolymers thereof to be produced without radial deformation of the tubes despite the slow crystallization of the polymer and copolymers. The methods can produce tubes of P4HB and copolymers thereof with tightly defined outside and inside diameters which are required for medical application. These tubes are produced by radial expansion at temperatures above the melting temperature of P4HB and copolymers thereof, and using low tube cooling temperatures and prolonged cooling times. The tubes made from P4HB and copolymers thereof are flexible, and can be prepared with high elongation to break values.

The present invention relates to a three-dimensional (3D) pen with a novel structure which enables filaments having various colors to be easily selected and used. According to the 3D pen according to the present invention, a user laterally rotates the adjustment lever (25) to allow the driving motor (24) to be connected to different transfer rollers (22), thereby selectively transferring and discharging a plurality of different filaments (1) forward. Therefore, the 3D pen has a very simple structure and has an advantage in that the filaments (1) having various colors can be easily selected to manufacture objects having various colors.

A screw extruder which extrudes a kneaded material includes a screw having a helical flight provided on an outer peripheral surface of a shaft portion thereof, and a chamber housing the screw. In the screw extruder, a flight thickening portion is provided at a part which is a tip portion of the flight and is on the reverse side of a rotation direction of the flight.

A screw extruder which extrudes a kneaded material includes a screw having a helical flight provided on an outer peripheral surface of a shaft portion thereof, and a chamber housing the screw. In the screw extruder, a flight thickening portion is provided at a part which is a tip portion of the flight and is on the reverse side of a rotation direction of the flight.

An extruder that includes: an extruder barrel with an inlet end and a discharge end; a rotatable screw element disposed axially within the barrel with a screw inlet end proximate the inlet end and a screw discharge end proximate the discharge end of the barrel; a shaft extending axially through the screw element and comprising a central bore with an opening proximate to the inlet end of the barrel and extending through the shaft to a closed terminal end; and a coolant delivery conduit extending axially within the bore comprising a coolant inlet end proximate to the inlet end of the barrel and a coolant discharge end. The closed terminal end of the bore is located at a predetermined distance upstream from the screw discharge end. Further, the coolant discharge end is located within the bore and proximate to the closed terminal end of the bore.

The invention relates to a process for removal of volatile components from an olefin polymer, the process carried out in an extruder comprising at least one vacuum degassing zone, said process comprising the steps of: (a) introducing a stream of an olefin polymer into the extruder; (b) extruding the olefin polymer in the extruder at a temperature which is higher than the melting temperature of the olefin polymer but lower than the decomposition temperature of the olefin polymer, thereby producing an olefin polymer melt having reduced amount of volatile components, wherein the process in the extruder has a residence time distribution broadness (σ2) in the range of 800 to 4000 as define by equation (1) wherein: σ2 is the residence time distribution broadness, T is the mean residence time, t is the interval of residence time a fluid element of the olefin polymer spends in the extruder, E(t) is the residence time distribution function, and wherein the process optionally comprises a step (c) where the melt of the olefin polymer is passed through a die zone to a pelletizer for pelletizing the obtained olefin polymer.

σ.sup.2=∫.sub.0.sup.∞(t−τ).sup.2E(t)dt   equation (1)

An extruder screw includes a screw main body, conveyance portions, barrier portions, and paths. The raw materials, the conveyance of which is limited by the barrier portions, flow in from the entrance. The raw materials flowing in from the entrance flow through the paths in an opposite direction to a conveyance direction of the conveyance portions. The exit is opened in the outer circumferential surface of the screw main body at a position on an upstream side in the conveyance direction in the conveyance portions in which the entrance is opened.

A device and a method for extruding plastics, comprising an extruder screw, a housing with a cavity, a drive unit for rotatably driving the extruder screw, a heating element arranged on the housing alongside the extruder screw, a filling unit through which shredded plastic can be supplied into the cavity, and a filler metering device. Upon rotation, the extruder screw conveys the shredded plastic in the transport direction along a longitudinal axis of the extruder screw. The housing has a feeding port for the filler opening into the cavity, wherein the filler metering device is connected to the feeding port and is designed for supplying a filler dispersed in a gas stream into the cavity.

Liquid mixing processes are provided for producing an elastomeric composition as a function of a selected elastomeric composition recipe. A system (10) is also provided for the production of an elastomeric composition according to the disclosed liquid mixing processes.