Abstract:
Injection molding systems and methods useful for making microcellular foamed materials are provided as well as microcellular articles. Pressure drop rate and shear rate are important features in some embodiments, and the invention provides systems for controlling these parameters in an injection molding system. Another aspect involves an injection molding system including a nucleator that is upstream of a pressurized mold. Another aspect involves an extrusion system with the reciprocating screw for forming a single phase solution of non-nucleated blowing agent and polymeric material. Another aspect involves very thin walled microcellular material and very thin walled polymeric material. Another aspect provides a method for producing high weight reductions in very thin-walled parts with surfaces that have no noticeable differences from non-foamed parts.
Abstract:
The invention includes retrofitting a plasticating machine for the working and forcing of plastic material into a moldor die, the machine including an elongated housing having a first or proximal end and a second or distal end, and elongated screw shaft with a screw flight therearound. The screw shaft is rotatably supported in the elongated housing, for the working of plastic between the screw shaft and the elongated housing with at least one delivery conduit generally longitudinally arranged through the screw shaft, from a location proximal to the distal tip end of the screw. To accomplish such delivery, the screw shaft is replaced with a corresponding screw shaft with a bore extending through the distal tip end thereof, or the existing screw shaft is machined to have such a bore extend therethrough, from location proximal to the distal end out through the distal tip end. The bore in one embodiment may extend completely through the screw shaft, from its proximalmost end to its distalmost tip end. The conduit may be arranged to be movable in the bore, with respect to the screw shaft to permit delivery of a medium through the screw shaft to any plastic being worked by the machine. The medium may be any single or combination of components selected from the group comprising vapor, liquid, gas, powder or solid, to control the machine or treat any plastic being worked therefrom.
Abstract:
The present invention comprises a method for delivering a medium such as a gas, vapor or liquid into a melted plastic in a mold via an elongated screw shaft rotatably supported in a housing, the method including the steps of providing the screw shaft with a bore longitudinally therethrough from a proximal end to a distal tip end thereof, rotating the screw shaft in the housing to move plastic therethrough, and into the mold, introducing a gas, vapor or liquid into the bore, to permit the gas, vapor or liquid to be delivered through the bore, and into the molten plastic in the mold through the distal tip end of the screw shaft.
Abstract:
A method and apparatus for the preparation of multicolor, multidensity and/or multithermoplastic foam and products composed thereof. Heat-plastified foamable gels of a thermoplastic resin or resins containing blowing agents are combined and extruded simultaneously through the same orifice of a die and expanded into a foam. The color, density and/or thermoplastic resin of the secondary foamed gel or gels can form a multitude of patterns or shapes that include waves, diagonals, stripes and/or continuous coverage over the entire surface of the primary foamed gel. These patterns or shapes can be on the surface and/or within the cross-section of the primary foamed gel.
Abstract:
An apparatus for the extraction of melt samples, particularly from continuously operating plastics processing plants, has a test sample mould which is connected to a melt channel via a transfer channel. There are provided a shutoff device and a device for transferring the melt into the mould. In the transfer channel there is arranged a suction piston which sucks the melt out of the melt channel into the transfer channel which in this case is opened simultaneously. In addition, there is provided a pressure piston for injecting this melt into the moulding chamber. An apparatus of particularly simple construction is created in this way and permits extraction of melt samples without the melt coming into contact with the atmosphere, no dead spaces at all being created at the same time in the melt channel during the time when no melt samples are extracted.
Abstract:
A disclosure relates to an apparatus for extruding and forming blanks from a rubber or polymeric material comprising a pair of hydraulic ram operated extruders having outlets connected to a common delivery conduit. A screw extruder is also connected to the conduit and a control valve controls flow between the respective extruders and conduit such that in one position of the valve one of the ram operated extruders is connected to the conduit outlet delivery of extrudate and the other extruder is connected to the screw extruder to receive a fresh charge of extrudate. A closed hydraulic circuit links the hydraulic rams of the two ram extruders whereby filling of one of the extruders causes that ram to retract and pump the hydraulic fluid therefrom to the other extruder to cause that ram to extend and thereby discharge the extrudate therein and vice versa. By feeding extrudate from the screw extruder, the hydraulic ram extruder being charged is caused to receive extrudate and the ram extruder discharging extrudate is caused to discharge extrudate. A cutter mechanism is provided at the outlet of the conduit severing the extrudate repeatedly at a rate determined by the advance/retraction of one of the hydraulic ram extruders to form blanks of substantially equal volume.
Abstract:
A diverting plate having the same external configuration as a changeable strainer in a flow line for a molten polymer. Contamination is removed by substituting the plate for a strainer.
Abstract:
In a rubber extruder, a rubber sample is sampled while the rubber extruder is operating. In a rubber extruder formed of a cylinder and a screw arranged in the cylinder, a rubber sample taking-out path is provided in the vicinity of an outlet-side end portion of the screw and in front of a rubber taking-in port of a pair of gears of a gear pump. A path opening/closing means including a ball valve which opens/closes the rubber sample taking-out path is also provided so that a part of rubber extruded by the screw is taken out as a sample by opening/closing the ball valve at predetermined timing.
Abstract:
Injection molding systems and methods useful for making microcellular foamed materials are provided as well as microcellular articles. Pressure drop rate and shear rate are important features in some embodiments, and the invention provides systems for controlling these parameters in an injection molding system. Another aspect involves an injection molding system including a nucleator that is upstream of a pressurized mold. Another aspect involves an extrusion system with the reciprocating screw for forming a single phase solution of non-nucleated blowing agent and polymeric material. Another aspect involves very thin walled microcellular material and very thin walled polymeric material. Another aspect provides a method for producing high weight reductions in very thin-walled parts with surfaces that have no noticeable differences from non-foamed parts.
Abstract:
The invention comprises a plasticating machine for the working and forcing of plastic material into a mold, the machine including an elongated barrel housing having a first or proximal end and a second or distal end, and an elongated screw shaft with a screw flight therearound, the screw shaft being rotatably supported in the elongated barrel housing, for the working of plastic between the screw shaft and the elongated housing. At least one delivery conduit is generally longitudinally arranged within the wall of the housing. The delivery conduit with the housing wall may be arranged to heat or cool the screw and any plastic being worked therethrough. In a further embodiment, it may permit delivery of a medium within the wall, from an upstream location of the housing, into the primary flow path of any plastic being driven from the machine and into a mold.