Abstract: A single screw micro-extruder for a 3D printer includes a feed chamber with an opening for receiving solid plastic pellets. An extrusion barrel extends from the feed chamber and has an inner conically shaped bore between input and output ends. The bore has a mouth at the input end and an exit opening at the output end with a melt section therebetween. A rotatable screw is attached to a torque drive of the printer, and extends through the feed chamber and conical bore of the barrel. A constant or tapered diameter of the screw root core, from the input end toward the output end of the barrel, forms a decreasing channel root depth in a helical path for compression between a root core surface and an inner surface of the bore for pressurizing melt in the melt section of the barrel to exit an extrusion nozzle.

Abstract: A plasticating barrel is provided with a primary heating system having at least one laminated ceramic heater, where the ceramic heater has an electrical insulating layer interposed between the ceramic heater layer and an outer wall of the barrel, and the longitudinal length of the ceramic heater is arranged over a portion of the barrel length. A secondary heating system may also be provided and overlaps, at least in part, the primary heating system.

Abstract: The apparatus and method that best results in low shear to melt shear-sensitive materials, such as polyethylene terephthalate, polyvinylchloride, acrylonitrile butadiene styrene, acrylics and/or resins with fiber fillers, without sacrificing process speed and/or cycle time, comprises the use of a barrel, screw and induction heating coil. The screw, in this case, preferably includes a low volumetric compression ratio, a relatively short feed section, an extended transition section, and a typical metering section.

Abstract: A plasticating barrel is provided with a primary heating system having at least one laminated ceramic heater, where the ceramic heater has an electrical insulating layer interposed between the ceramic heater layer and an outer wall of the barrel, and the longitudinal length of the ceramic heater is arranged over a portion of the barrel length. A secondary heating system may also be provided and overlaps, at least in part, the primary heating system.

Abstract: Disclosed herein is an apparatus and method with inductive heating of an electrically conductive workpiece such as a barrel used in molding or extrusion, having a layer of thermal insulation interposed between the induction windings and the workpiece, and using alternating current (AC) at an elevated frequency. Further, variable pitch induction windings may be used to generate a non-uniform and calculated heat input profile, such as to compliment the configuration of a screw for transporting material through the barrel.

Abstract: Apparatus according to this invention for plasticating a resin polymer, especially polypropylene, includes a barrel having an inlet, outlet, and inner surface. A screw, located within and closely spaced from the inner surface of the barrel, has a longitudinal axis extending from the inlet toward the outlet, and includes length sections arranged in a series along the axis. The screw includes a core and a main flight located on and projecting radially from the core, extending in a helix along the axis, and having a push side and a trailing side. The screw sections include a feed section, a transition section following the feed section, a metering section following the transition section, and a barrier melting section following the metering section.

Abstract: An apparatus for plasticating rubber, thermoset or thermoplastic materials according to this invention includes a barrel having a wall extending axially and laterally and having an outer surface and an inner surface. The wall has a thickness formed with mutually spaced holes extending at least partially through the thickness. The barrel is formed of material having a first, relatively low coefficient of thermal conduction conductors having a coefficient of thermal conduction greater than the first coefficient are each located in and engage a hole. Heat applied to the outer surface is conducted rapidly through the wall thickness along the length of the conductors to the inner surface, thereby heating and cooling material being processed located in a cavity surrounded by the wall.

Abstract: A rotatable screw for moving material in a plasticating process along an axis through a conduit from an inlet to an outlet. The screw having a feed section, barrier melting section, reorientation section and metering section disposed sequentially downstream. The screw includes an axial core, and a helical main flight that extends radially from the core and is formed with recesses located at the first periphery and extending through the thickness of the main flight and radially toward the core. A helical secondary flight extends radially from the core between successive helical passes of the main flight, and is formed with recesses extending through the secondary flight and toward the core. Materials conveyed along the metering section can cross through the main flight at the recesses and recirculate, in addition to passing over the periphery of the secondary flight, for still further enhanced and homogenous mixing, before reaching the outlet.

Abstract: A heat transfer roll for producing sheet material, particularly material having a cross-section whose thickness varies across the width of a sheet being formed, includes a journal on which the roll is rotatably supported, and at least two cooling channels at the surface of the roll that can be supplied with various fluids at various flow rates and temperatures. Fluid in the first and second channels flows at predetermined longitudinal positions at the roll surface. The first channel includes cylindrical spiral portions and the second channel includes a circular cylindrical channel located between the spiral portions. A diverter provides hydraulic flow continuity across the second flow channel to first and second portions of the first flow channel. Risers carry fluid radially outward to the flow channels at the outer surface of the roll.

Abstract: A rotatable screw for moving material in a plasticating process along an axis through a conduit from an inlet to an outlet. The screw having a feed section, barrier melting section, reorientation section and metering section disposed sequentially downstream. The screw includes an axial core, and a helical main flight that extends radially from the core and is formed with recesses located at the first periphery and extending through the thickness of the main flight and radially toward the core. A helical secondary flight extends radially from the core between successive helical passes of the main flight, and is formed with recesses extending through the secondary flight and toward the core. Materials conveyed along the metering section can cross through the main flight at the recesses and recirculate, in addition to passing over the periphery of the secondary flight, for still further enhanced and homogenous mixing, before reaching the outlet.

Abstract: A plasticating screw having a feed section, barrier melting section, reorientation section and metering section disposed sequentially downstream wherein solid material is moved from a trail side of a main flight to a push side of the main flight in the reorientation section. The reorientation of solids is accomplished by discontinuing a barrier flight at a terminal end of said barrier melting section. The main flight decreases its pitch and continues into the reorientation section, which has a longitudinal length at least 360° about the screw axis. A melt channel and solids channel in said barrier melting section merge into a substantially uniform reorientation channel in the reorientation section so that solid plastic material conveyed along the reorientation section moves toward the push side of the main flight.

Abstract: A mixing section for a feed screw includes a body portion defined along a longitudinal axis. The mixing section further includes a primary flight defining a helical channel, wherein the primary flight is helically wound in a first direction about the longitudinal axis. The primary flight forms a first acute angle with respect to a first plane including the longitudinal axis and defines a cross channel to allow fluid communication between adjacent portions of the helical channel. The cross channel is defined along a second plane such that the second plane forms a second acute angle with respect to the first plane. The first and second acute angles are located in the same quadrant and the second angle is less than the first angle.

Abstract: A cylindrical apparatus or module to be included in a screw of a plasticating device. The screw has a helical flight disposed within and cooperating with the inner-wall of a heated barrel to form an upstream where material is fed into and a downstream where material exits the device. The cylindrical module has a helical channel traversing in a reverse helical direction compared with the direction of the flight. Input grooves extend in the surface of the module with input groove openings beginning within the helical channel and terminating in a dead end before intersecting the channel upstream. Output grooves, being adjacent to the input grooves, extend in the surface of the module with output groove openings beginning within the helical channel and terminating in a dead end before intersecting the channel downstream. A barrier is between the pair of adjacent input and output grooves to prevent direct communication therebetween.

Abstract: A plasticating screw having a main channel defined by a helical flight disposed within and cooperating with an inner-wall of a heated barrel. The screw has a longitudinal portion with a plurality of staggered rows of noncontinuous advancing grooves arranged in the main channel thereof. The axis of each row of advancing grooves being substantially parallel to the helical axis of the adjacent helical flight of the longitudinal portion. A noncontinuous helical channel is formed therein traversing in a reverse direction, compared with the direction of the helical flight, the channel having a plurality of retracting grooves. Each retracting groove cuts through at least one pass of the main channel of the longitudinal portion, including the advancing grooves therein, and intersects and passes through the helical flight at least once, so that molten resin can back flow and re-circulate therethrough.

Abstract: A deflection dampening apparatus for a process roll. The dampening apparatus having C-shaped first and second portions with both portions pivotally interlocking to form a ring. The C-shaped portions have an inner base and a notched outer surface comprising a pair of fined side walls. A plurality of screws are attached through a threaded opening in the inner base with a wedge shaped washer secured therebetween. The screws and wedge shaped washer communicate with the finned side walls, whereby tightening each screw causes the fins to extend outwardly to wedge between a cantilevered inner shell assembly and a cylindrical core of the process roll. When securely wedged therebetween, the dampening apparatus modifies the cantilever effect of the inner shell assembly of the process roll.

Abstract: An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a low compression ratio, flight with a reduced helical angle, and a conical, tapered front end section where at least one-half flight of the thread has a pitch associated therewith which is different from the pitch of the remainder of the thread and where the diameter is less than the diameter of the remainder of the root body.

Abstract: An extruder for plasticating and extruding an extrudate, and an extrusion screw used with the extruder form the subject of this invention. The extruder screw includes an elongated root body and a thread portion helically wound about the root body and extending along the length. The screw having a low compression ratio, flight with a reduced helical angle, and a conical, tapered front end section where at least one-half flight of the thread has a pitch associated therewith which is different from the pitch of the remainder of the thread and where the diameter is less than the diameter of the remainder of the root body.

Abstract: A plasticating apparatus including a rotating screw having a helical flight disposed within and cooperating with the inner wall of a heated barrel. Solid resinous material is introduced to a helical valley extending between said flight to be heated and plasticized by said apparatus while being advanced towards an outlet opening by the rotation of said screw. The screw has a meter section for working, melting and mixing said resinous material at high temperatures. The bottom surface of the helical valley in said metering section is divided into side by side relatively shallow and relatively deep levels. Within the metering section is a transit channel having a reverse helical direction as compared with the helical direction of the flight. Because of the reverse helical direction of the transit channel, the transit channel intersects the helical flight and helical valley with the transit channel cutting therethrough.

Abstract: A plasticating screw and method of plasticating without thermal degradation problems. Said screw having a metering section with a helical flight disposed within and cooperating with the innerwall of a heated barrel. In particular, solid resinous material is introduced to a helical valley extending between said flight. The resinous material is heated and plasticized by said apparatus while being advanced along a helical path towards an outlet opening by the rotation of said screw. The bottom surface of the helical valley in said metering section having a plurality of geometrically shaped surfaces in side-by-side relation with at least two of said shaped surfaces being sloped. During operation, the level differential between the shaped surfaces induces a continuous tumbling, variable shear and mixing action upon the molten resin as the molten resin in the metering section flows along the helical path.

Abstract: An apparatus and method for controlling thermoplastic mixing in a plastic extrusion machines used for injection molding, blow molding or other reciprocating molding process. The plastic extruder having a rotating helical screw within a cylindrical shell with an automatic shut-off and mixing valve secured to the helical screw at the downstream end of the screw. The automatic shut-off and mixing valve includes a unitary valve body with a poppet. A plurality of mixing groove pairs are arranged extending substantially longitudinally on the surface of the valve body. Select angular bores extend from the groove pairs to the poppet. The poppet is axially movable within and rotatable relative the valve body. The poppet has an axial stem extending into a longitudinal axial bore within the valve body. An elastic means is positioned on the rearward end of the poppet maintaining the valve in a normally closed position against a seating surface of the valve body when there is no rotation of the helical screw.