A screw having a longitudinal body and, around this longitudinal body, at least one flight extending in the shape of a helix, the flight including, over part of its length, internal partitioning delimiting a plurality of internal channels that extend in the shape of helices following the helix shape of the flight. The screw includes manifold-like cavities into which the ends of the interior canals open, the manifold-like cavities extending radially and opened into a longitudinal bore of the body at longitudinally spaced locations. This screw can be produced by additive manufacturing using laser-induced fusion.

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.

An additive manufacturing system includes a slip clutch coupled to an actuator of a mechanical driver that feeds solid extrusion material into a heater for supplying thermoplastic material to a manifold in an extruder head. A speed of the actuator can be set to enable the actuator to operate at a rotational speed that is slightly greater than the rotational speed of the mechanical mover. This configuration enables the pressure of the thermoplastic material in the manifold of the extruder head to be in a predetermined range no matter how many nozzles are opened in the extruder head.

The installation is for producing a coextruded profiled element for tires that is made from rubber compounds of different compositions. The installation includes at least one first extruder having a screw with a longitudinal axis and at least one second extruder having a screw with a different longitudinal axis. An extrusion head is connected to each of the extruders by appropriate ducts. The feed inlet of each extruder is connected to the delivery orifice of a gear pump.

A method of recycling a mixed plastic waste comprising plastics having different melting temperatures includes conveying the mixed plastic waste through an extruder such that at least some of the higher melting point plastic is passes through the extruder without melting and is present in the extrudate as solid material.

Systems and approaches for controlling an injection molding machine having a mold forming a mold cavity and being controlled according to an injection cycle include extruding a molten polymer according to an extrusion profile and measuring at least one variable during the extrusion profile with a first sensor. At least one extrusion operational parameter is adjusted based on the measured variable. The extrusion profile is terminated upon the molten polymer exceeding a first threshold, and the molten polymer is injected into the mold cavity according to an injection profile via a screw that moves from a first position to a second position. Upon completion of the injection profile, a recovery profile commences in which the screw is moved to the first position.

Embodiments of films, for example, infrared absorbing, heat retaining films, comprise at least one polymer selected from: a low density polyethylene (LDPE) having a density range of 0.900 g/cc to 0.930 g/cc and a melt index (I.sub.2) of 0.3 g/10 min to 2.0 g/10 min as measured in accordance with ASTM D1238; a linear low density polyethylene (LLDPE) having a density range of 0.900 g/cc to 0.930 g/cc and a melt index I.sub.2 of 0.3 g/10 min to 2.0 g/10 min; and a ethylene vinyl acetate copolymer having a vinyl acetate content ranging from 3 wt. % to 27 wt. % and a melt index I.sub.2 of 0.2 g/10 min to 10 g/10 min. The films also comprise a hybrid filler comprising (i) a layered double hydroxide, and (ii) an inorganic powder complex having a particle size distribution defined by a median diameter (D50) of 1.5 to 20 m.

A screw extruder for extruding a kneaded material includes a screw and a casing housing the screw and having a material supply port on an upstream side in an extrusion direction of the kneaded material and a tip-side opening on a downstream side in the extrusion direction. A pressure sensor for measuring a pressure inside the casing is provided between a downstream end of the supply port and the tip-side opening of the casing. A rotational speed of the screw is controlled depending on the pressure measured by the pressure sensor.

The present invention relates to a processing technology for manufacturing seepage irrigation pipe with alternating effluent sections and non-effluent sections, and in particular, to the field of underground seepage irrigation in agriculture and forestry. The processing technology combines the production unit for water-effluent pipes with the production unit for non-effluent pipes, and produces the seepage irrigation pipeline by adjusting the raw material ratios, controlling the spindle speed, spindle acceleration time, and spindle deceleration time of the two pipeline production units, to generate a seepage irrigation pipe with alternating effluent sections and non-effluent sections. The lengths of the effluent sections and non-effluent sections can be adjusted, the pipe wall thickness can also be adjusted by adjusting the inner and outer diameter of the internal mold of the pipe forming unit, a seepage irrigation pipe with alternating effluent sections and non-effluent sections is environment-friendly, efficient, water-saving, and useful for underground irrigation.

A process and associated system for creating color effects in extrudable material, such as plastic and metal for example, are presented. Flows of first and second viscous materials of respective colors are provided and then combined in a predetermined pattern to form a stream of combined viscous material. In a first aspect, the flow rate of the first viscous material is caused to vary over time in order to vary an amount of the first viscous material in the stream. In a second aspect, which may be used alone or in combination with the first aspect, the first and second viscous materials have distinct viscosities to reduce an amount of color blending between the first color and the second color in the stream of combined viscous material. A static mixer may then be used to apply a predetermined dividing, overturning and combining motion to the stream of combined viscous material to partially mix the first viscous material and the second viscous material, such that upon exiting the static mixer, the first material of the first color and the second material of the second color form a color pattern in the stream of combined viscous material. Sheets of extrudable material may be created using such process and used in the manufacturing of many different products including for example kayaks and stand-up paddle boards.