Abstract: A device for manufacturing a double-walled thermoplastic pipe with a connecting sleeve has a molding tunnel with a succession of molds for forming a corrugated molding wall and a connecting sleeve, respectively. An extrusion device extrudes a first flexible tube into said molding tunnel and a second flexible tube into said first flexible tube. A first gas channel is arranged for generating a pressure between said first and second flexible tubes. A compressed-gas control device is connected to said first gas channel for generating a pressure p1 or a pressure p2 in said space between said first and second flexible tubes by compressed air emerging from said first gas channel. A second compressed-gas control device is connected to a second gas channel for guiding compressed gas onto an inner side of said second flexible tube. Said first pressure controller is connected to said first gas channel via a compressed-gas line that is connected to an additional compressed-gas reservoir for gas exchange therewith.

Abstract: The present invention relates to an expansion tube that has a plurality of expansion slits on the outer peripheral surface thereof long a longitudinal direction, each of the expansion slits having a predetermined width and a relatively larger length than the predetermined width, and an apparatus for manufacturing a heat shrinkable tube, having the expansion tube, that can regularly and fast expand the heat shrinkable tube, and after the expansion, regularly and fast cool the heat shrinkable tube by the cooling water sprayed through the slits, thereby rapidly and stably manufacturing the heat shrinkable.

Abstract: A thermoforming apparatus having a mold with an internal vacuum chamber and a quench for cooling a thermoplastic sheet while it remains on the mold. Because the quench cools the sheet, conventional cooling lines are eliminated from the mold. One method of using the thermoforming apparatus includes pushing a heated sheet towards the mold with a plug assist, drawing the heated sheet over the mold, creating a partial vacuum in the vacuum chamber of the mold to maintain the sheet on the mold and quenching the sheet on the mold in a quenching tank by moving the quenching tank to the mold.

Abstract: A method for manufacturing a composite structure is disclosed herein. The process uses a frame and selectively pressurizable forms. The forms define the interior members of the composite structure and frames define the exterior surface of the composite structure. Composite material is wrapped around the forms and the forms and composite material are placed in the frame. Selective forms are then pressurized and the composite material is co-cured together. A single piece co-cured fuselage incorporating a plurality of stiffeners is also disclosed in the application. The stiffeners are co-cured to the fuselage and may be in various patterns. The patterns may include an iso-grid pattern, and ortho-grid pattern, and a hoop-grid pattern.

Abstract: Disclosed is an apparatus and a corresponding method for producing a continuous foamed extrudate product in which the extrusion and initial expansion of the foamed extrudate is conducted within a chamber under a partial vacuum. The foamed extrudate is then removed from the chamber through an orifice submerged within a liquid baffle. The dimensions of the foamed extrudate are monitored as it approaches the orifice and, if necessary, the effective sizing of the orifice is adjusted through the movement of a pair of side gates and a single vertical gate arranged external the orifice to match opening to the foamed extrudate and impede the flow of liquid into the chamber through the orifice.

Abstract: A tubing expansion device (20) is adapted to be advanced axially, without rotation, through tubing (10) to be expanded. The device (20) comprises a body (22) and a plurality of expansion members (30,32,34) mounted on the body (22), the expansion members (30,32,34) being independently radially movable. The expansion members may be rotatable, or may be non-rotating.

Abstract: An improved method of imprint lithography involves using direct fluid pressure to press the mold into a substrate-supported film. Advantageously the mold and/or substrate are sufficiently flexible to provide wide area contact under the fluid pressure. Fluid pressing can be accomplished by sealing the mold against the film and disposing the resulting assembly in a pressurized chamber. It can also be accomplished by subjecting the mold to jets of pressurized fluid. The result of this fluid pressing is enhanced resolution and high uniformity over an enlarged area.

Abstract: A forming structure for use in an apparatus for making formed polymeric film. The forming structure comprises a first portion comprising a network of interconnecting members defining apertures, the apertures being spaced in a pattern defining a first percent open area, a second portion being solid and having no apertures and zero percent open area; and a third portion being a transition between and joining the first and second portions, the transition portion exhibiting a second percent open area, the second percent open area of the third portion being less than the first percent open area of first portion.

Abstract: This invention refers to a method and a device for use in connection with the fabrication of multilayer products (8) such as composites and bonded multilayer sheet products, ect. by means of the so-called “bagging technique,” to increase the compressive pressure (P) on the product being created beyond normal atmospheric pressure. In the bagging technique, which is used to join a plurality of different material layers with one another to form a unit via polymeric binder layers, atmospheric pressure is normally used to press the various objects together in that they are enclosed in a depressurized gas-impervious bag (9, 21) while the various layers are joined to form a unified product.

Abstract: A method and an apparatus for use in installing a liner in a conduit as part of a repair procedure, the apparatus including a sealing inlet port (106) for passage of the tubular liner (72) into an enclosed container (52) where an increased pressure is maintained to move the tubular liner into the conduit (179) and to evert it as it moves along the conduit. A clamp (80) holds one end of the liner to the outlet side of an everter box (50) supported on a frame (18) that may be mounted on a trailer hitch receptable. The sealing inlet port includes a pair of lips (112, 114) to press against the opposite sides of a flattened liner. Support members (148, 150) keep the lips from being forced back out toward the outside of the pressurized everter box and control friction between the lips and the liner. Inlet and outlet fittings are provided. The apparatus is portable on a trailer hitch receiver.

Abstract: An apparatus and method for aligning a disk with an imprinting surface are described. In one embodiment, the apparatus has a die which includes an air-bearing mandrel having a tapered nose to engage an ID of the disk, a circular imprinting surface having a centerline concentric with the air-bearing mandrel, and an air-bearing cavity to position the disk. The axial movement of the top die towards the bottom die guides the ID of the disk into coincident alignment with the centerline of the top die.

Abstract: The invention concerns a continuous manufacturing method which consists in producing a blank (E) by extrusion, bringing said blank to a temperature for molecular orientation, passing said blank around a radial expansion mandrel (12); gauging and cooling while subjecting the blank to axial traction. The radial expansion produced on the mandrel (12) is partial so that the internal diameter (B) of the blank (E), when it leaves the mandrel, is less than the nominal internal diameter (D) of the finished tube; performing an additional radial expansion of the blank, up to its nominal diameter, by internal fluid pressure. In permanent operating conditions, the inner surface of the blank (E) is no longer in contact with the mandrel (12).

Abstract: An external stabilizer or guide cage for plastic film extrusion has an upper frame comprised of a ring and structure for rotatably supporting the ring. A lower frame is suspended from the ring of the upper frame, and is positioned such that the lower frame surrounds the extruded tube. The lower frame can employ one or several banks of guide arms that keep the tube aligned axially as the tube is drawn upwards. The arms on the lower frame define an iris aperture, or a stack of iris apertures. The arms include channels for coolant flow. Heat transfers from the film to the guide arm. The upper frame includes a drive for rotating the ring and the lower frame of the guide cage over a predetermined arc, e.g., 60 degrees, to compensate for gauge variations in the film.

Abstract: A pressure box for thermoforming a heated sleet of thermoforming material against a mold includes a top plate, side plates, a downstream and plate and an upstream end plate. Each end plate includes a pair of plate members that define a slot open to the bottom of the end plate. A sheet strip of elastomeric material is mechanically held in the slot and extends below the end wall to a seal surface. The seal surface is laser cut to closely conform with the three-dimensional shape of the mold.

Abstract: A method for weakening a portion of a web includes moving a web in a machine direction between at least a first location and a second location, wherein the second location is positioned downstream of the first location, forming a line of weakness in the web at the first location, wherein the web has a first tensile strength across the line of weakness, and weakening the line of weakness at a second location, wherein the web has a second tensile strength across the line of weakness after the line of weakness is weakened at the second location and wherein the first tensile strength is greater than the second tensile strength.

Abstract: A mold for molding fibrous molding media includes upper and lower mold bodies defining a mold cavity, the upper and lower mold bodies being movable relative to each other to close the mold. The upper and lower mold bodies have respective upper and lower mold surfaces for contacting the fibrous molding media positioned within the mold, and have gas flow openings configured to direct gases into contact with the fibrous molding media. The mold also includes a source of gas connected to the gas flow openings.

Abstract: This invention relates to a novel apparatus and process for producing thermoplastic articles. In one aspect, the invention pertains to a process for manufacturing fiberglass products using a fiberglass material consisting of fiberglass strands commingled with heat-formable polypropylene strands. A molding apparatus comprising: (a) an air pressure chamber with an open side; (b) a flange plate fitted to the open side of the air pressure chamber, said flange plate having an opening therein for receiving a mold; (c) an upper bladder associated with the flange plate and covering the opening; (d) a base pressure plate; (e) a mold positioned on the base pressure plate; and (f) a locking mechanism for securing the air pressure chamber with the base pressure plate, and balanced air pressure in each chamber during molding.

Abstract: A system (10) is provided for perforating and consolidating an uncured laminate sheet (14) at a substantially low pressure in one cycle of operation. The system (10) includes a pinmat (20) that is coupled to a tool base (24). This pinmat (20) is comprised of a mat portion (28) and a plurality of pins (26) extending from the mat portion (28). These pins (26) are intended to displace discontinuous fibers (32) within the laminate sheet (14) so as to perforate the laminate sheet (14). Furthermore, the mat portion (28) has one or more ventilation holes (58) integrally formed therein for allowing gas adjacent to the pins (26) to be withdrawn therefrom so as to improve the consolidation of the laminate sheet (14). The system (10) also includes a positive pressure source (12) that is coupled to the laminate sheet (14) for forcing the laminate sheet (14) onto the pinmat (20).

Abstract: A method and system (10) having a flowable pressure pad (22) for consolidating an uncured laminate sheet (14) during a cure cycle is provided. The system (10) includes an autoclave machine (12) for utilizing a pinmat (20) for to perforate and consolidate the sheet (14). This pinmat (20) has a mat portion (28) and a plurality of pins (26) extending from the mat portion (28). These pins (26) are intended to penetrate the uncured laminate sheet (14) during a perforation cycle that occurs prior to the cure cycle. During the cure cycle, the autoclave machine (12) applies a predetermined amount of and pressure heat to the pressure pad (22) for a predetermined amount of time so as to cause the pressure pad (22) to flow around the protruding pins (26). This feature allows the pressure pad (22) to transfer a substantial portion of the applied pressure to the uncured laminate sheet (14) so as to improve consolidation of the sheet (14).

Abstract: Shaping tool for the polymerisation of profiled parts (P) made of a composite material, comprising a mould (10) formed of several unconnected elements (14, 16), a flexible and leak tight bladder (24) capable of pushing a part blank into contact with the walls of a cavity (12) formed in the mould (10), and devices (36) such as flexible walls or the leak tight bladders capable of holding elements (14, 16) of the mould (10) in contact with each other. The result is a part (P) with outside surfaces free of geometric and dimensional defects.

Abstract: A method for making a cargo liner or a floor mat using a plastic molding process wherein a male mold includes a steel rule about its perimeter or a female mold includes a groove about its perimeter creating a ridge in the molded article to allow trimming of surplus material from the article along the ridge such that the dimensions of the finished article are determined by the ridge. In a preferred embodiment, an article is molded in a thermoforming process, the article thus produced includes a channel edge which enhances the appearance of the finished article and improves its structural integrity.

Abstract: The present invention relates to a method and to Apparatus for molding a receptacle fitted with a covering label. The technical field of the invention is that of molding a receptacle out of plastics material. In a method of molding a receptacle fitted with a covering label (1b) which is inserted into the mold (93) prior to injection, the label is shaped and at least two edges of the label are joined together, after which the shaped label is placed on a male portion (91) of the mold.

Abstract: A device for controlling thickness of film in a blown film extruder has a blow head, a main cooling ring and an additional cooling ring. The additional cooling ring supplies separate additional air streams. A measuring and controlling device controls the thickness profile of a blown film. The measuring and controlling device scans the thickness of the blown film above a freezing zone. The device controls the additional air streams as a function of the measured blown film thicknesses. The additional cooling ring is a segmented ring arranged at the blow head of a blown film extruder adjacent the main cooling ring. A method utilizing device is likewise disclosed.

Abstract: A film is extruded from plastic material by an extruder. The film is orientated after extrusion. Material is mixed into the plastic so that when the plastic film is stretched, cavitation bubbles are formed in the material particles mixed into the plastic. During the orientation, gas is arranged to the plastic film under high pressure so that the gas diffuses in the cavitation bubbles and causes overpressure in them. Thus, it is possible to make a thin foamed film with a foaming degree over 70%.

Abstract: A system for producing a thermoformed contour trim component having enhanced finish and density characteristics in which a face good is laminated to an adhesive coated substrate in a molding process using cooperative shells A and B in which a positive gas pressure is applied to a mold shell such that the adhesive surface of the substrate and a face good and/or laminate layers in an assembly are directed into contact with a bonding force sufficient to bond the layers.

Abstract: A plastic resin extrusion line for the production of blown film includes an external thickness control device that provides a controllable amount of air from an inlet side through an annular region to one or two sets of lips. Barriers that can be manually or automatically controlled are provided in the annular region for localized control of air flow and thus for localized thickness control. The pressure drop across the barriers is significant relative to that in the lips.

Abstract: An improved method and apparatus for imparting a smooth surface to a gypsum fiber panels. The method involves imparting energy to the surface of the slurry as the slurry is dewatered just prior to rehydration. The apparatus used to impart the energy is an air lance including an air source such as a blower, a distribution manifold and a plurality of nozzles to direct the flow of air at the surface of the slurry. In operation, the air lance directs a flow of air against the surface of the slurry. The flow disrupts the slurry to a fraction of its total depth, thus dispersing clumps or flocs of crystals in the depth that would give the surface of the finished panel a rough surface if they were allowed to remain.

Abstract: A mould tool comprises a primary cavity part (201), a core part (202), a secondary cavity assembly (203) and an actuation ring (204). The primary cavity part (201) is attached to the fixed platen of a moulding machine in use and incorporates an injection gate (211). The core part (202) is attached to the moving platen and has a fixed portion (2021) having outside its preform shaping surfaces (20211) four pivot points (224)—of which two are shown—for the secondary cavity petals (2030), of which there are four. Also the core part incorporates a movable portion (2022), comprised of a preform shaping end plate (20221), a carrier (20222) for the end plate, a pair of movement rods (20223) to which the carrier is attached and which are housed in bores (20224) in the core (202) via linear bearings (20225).

Abstract: A mold station for hot shaping plate-shaped polymer-bound plastics, thermoplastics, mineral plastics, into three-dimensional molded bodies such as bathtubs, sinks, washbasins, washstands, facings and shields, furniture parts, work surfaces, window sills and the like with a mold arrangement accommodated in a frame and in which are located at least one mold part for receiving the material to be molded, a membrane clamped over the mold part. The membrane is substantially impermeable to gas and elastically stretchable. A pressure difference is generated between the two sides of the membrane, characterized by the additional provision in the frame of the mold arrangement of a heating or cooling arrangement with two plate-shaped heating or cooling elements for pre-tempering of the material to be molded that can move in two directions that are substantially vertical with respect to each other.

Abstract: The invention concerns a mold for transforming plastic and/or composite materials, such as thermoplastic and thermosetting polymers and vulcanizable compounds, comprising a mold body (3, 3a, 3b) provided with an impression (4, 4a, 4b). The invention is characterized in that it comprises heating means which directly heat the material to be transformed or an intermediate surface impression adjacent to the material without using heat conductivity of the mold body (3a, 3b) and/or of the impression (4, 4a, 4b) to heat the material to be transformed.

Abstract: To make holes in ceramic green sheets that are needed to create feedthroughs, it is proposed to make the holes by using a gas that is under a higher pressure than atmospheric pressure and that is expelled in a pulsed manner from a pressure vessel and thereby acts on a principal surface of a ceramic green sheet, at at least one location at which a hole is to be made, in such a way that material is shot out of the ceramic green sheet at that location. This eliminates the disadvantages associated with the use of punches to punch holes.

Abstract: The invention relates to a process for shaping plate-shaped thermoplastic material into three-dimensional molded bodies with the process steps: insertion of the heated plastic plate to be shaped into a concave mold part, sealing the mold part at its upper edge by covering with a membrane made of a material impermeable to gas and elastically stretchable, pressing the membrane onto the mold edge by means of a rigid covering, and supplying compressed gas to the space between the membrane and the covering, along with an arrangement for carrying out the process.

Abstract: An adaptation device and method for molding a dental material to a die in the preparation of a dental coping with the die having the shape of a tooth to be restored and with said dental material placed over said die. The adaptation device includes a base for placement of the die, a cover mounted on the base over the die to form an enclosed chamber, an inlet opening extending through the cover into communication with the chamber, a source of a gaseous fluid connected to the inlet opening for pressurizing the chamber, an outlet opening extending through the base in proximity to said die and diaphragm means removably positioned in the chamber to surround the die and to isolate the outlet opening from the chamber such that upon pressurizing the chamber the diaphragm is caused to collapse about the die and to apply a uniform pressure over the dental material for adapting the dental material to the die.

Abstract: Apparatus for moulding composite materials comprises a frame (8) holding the margins of a pair of elastomeric membranes (4, 5) substantially in a plane in facing relationship. The frame (8) is secured within a moulding chamber formed by upper and lower sections (1, 2) respectively to divide the moulding chamber into a mould side MS which contains a mould form (9) and an opposite side OS. A jack diagrammatically illustrated at (13) is provided for effecting relative movement between the frame and the mould form (9) in the direction generally perpendicular to the plane of the frame. A resin introduction port (19) is provided for introducing resin between the membranes (4, 5) at a central region Ducting (11) is provided for aspirating the inter-membrane space, and inlet ducts OSI and MSI and outlet ducts OS2 and MS2 are provided for respectively pressurising and aspirating the mould opposite side OS and the mould side MS of the moulding chamber. To be accompanied, when published, by FIG. 1 of the drawings.

Abstract: An apparatus for molding balloon catheters is disclosed. The balloon may be molded by providing a polymeric tube within a mold having an interior cavity in the shape of the desired balloon. Microwave energy, which may be generated by a gyrotron, may then be directed toward the mold, to heat the polymeric material without heating the mold. Once heated, pressurized fluid may be injected into the tube to blow the polymeric material against the interior cavity whereupon the material can cool to form the balloon or can be further heatset by additional microwave energy and be cooled to form the balloon.

Abstract: An apparatus and method for molding balloon catheters is disclosed. The balloon may be molded by providing a polymeric tube within a mold having an interior cavity in the shape of the desired balloon. Microwave energy, which may be generated by a gyrotron, may then be directed toward the mold, to heat the polymeric material without heating the mold. Once heated, pressurized fluid may be injected into the tube to blow the polymeric material against the interior cavity whereupon the material can cool to form the balloon or can be further heatset by additional microwave energy and be cooled to form the balloon. In accordance with one embodiment, microwave energy can also be used without a mold to form a medical device.

Abstract: The invention concerns a continuous manufacturing method which consists in producing a blank (E) by extrusion, bringing said blank to a temperature for molecular orientation, passing said blank around a radial expansion mandrel (12); gauging and cooling while subjecting the blank to axial traction. The radial expansion produced on the mandrel (12) is partial so that the internal diameter (B) of the blank (E), when it leaves the mandrel, is less than the nominal internal diameter (D) of the finished tube, performing an additional radial expansion of the blank, up to its nominal diameter, by internal fluid pressure. In permanent operating conditions, the inner surface of the blank (E) is no longer in contact with the mandrel (12).

Abstract: The apparatus for shaping thermoplastic materials, in particular for producing moulded parts with a large height of the moulded part, comprises a suction-pressure bell and a lower part which can be locked to each other by a locking device. Resting on the lower part are a mould and a clamping frame, while the upper clamping frame can be securely clamped by working cylinders. In the locked state, the clamping frames are braced by a seal, which is arranged between the suction-pressure bell and the upper clamping frame. The seal extends over the entire circumference of the suction-pressure bell and is able to be pressed against the upper clamping frame by a pressure medium.

Abstract: An apparatus for shaping thermoplastic materials or for laminating backing parts includes a turntable driven by a rotary drive and having rests for receiving supporting devices for lower molds or backing parts. The turntable has a plurality of receiving places which can enter alternately into a preliminary blowing box, where a molded part can be shaped in conjunction with an upper mold arranged on an upper table. The preliminary blowing box has a front wall with an opening, facing the rotary drive. The turntable has a separating wall with flanges on both side which engage a wall indentation which surrounds the rotary drive and consequently bounds the preliminary blowing box, in order to seal the opening. A seal which can be shaped by means f a pressure medium and can be pressed against the separating wall is located in the front wall of the preliminary blowing box about the opening.

Abstract: Apparatus for producing plastic film, of the type in which molten plastic is extruded through an annular die to form a tubular bubble which is expanded by air blown into the bubble, and a collapsing frame for forming the bubble into a flat tube prior to passing the tube through a nip formed between rollers, in which opposed, converging reaches of endless belts are used for the collapsing. The belts have their upstream ends held by a pair of first rollers spaced apart on opposite sides of the bubble, and have their downstream ends held by a pair of nip rollers which hold the belts together to form a nip for the collapsed tube. Pulleys and a belt, or gears, are provided which rotatably interconnect the pinch rollers and ensure that the belts entering the nip travel at the same surface speed.

Abstract: A method for producing open-ended biaxially oriented containers includes forming a biaxially oriented intermediate by blow forming, without plug assist, a sheet of unoriented thermoplastic material into a forming tube to a depth of draw sufficient for full orientation of the side walls. The blow formed intermediate is placed on a male form a predetermined size, shape, and texture. The intermediate is heated above the orientation temperature of the thermoplastic material to heat shrink the intermediate onto the surface of the male form. The formed container is then removed from the male form.

Abstract: An extrusion system for extruding a layer of a plastic or rubber material onto a work piece without having to continuously adjust the extrusion system during the “set-up” mode to “full-run” mode, wherein the extruded layer exhibits a predetermined cross-section size and a uniform wall gauge concentricity.

Abstract: A semiconductor device assembly with a gap to be filled has thermal vias formed in the supporting substrate. After the semiconductor device is connected to the substrate and fill material positioned about the gap to create a seal, a vacuum is drawn through the thermal vias and a pressure applied to the fill material to urge the fill material into the interior of the gap.

Abstract: The invention refers to a plant and a holding device in connection with heat treatment of articles (3), which is at least partly manufactured in a thermosetting composite material. The holding device, which is comprised by the plant, includes a base element (1), and intermediate element (2), which rests on the base element (1), and at least a support member (4), which is fixable to the intermediate element (2) and arranged to support said article (3) on the intermediate element during the heat treatment The intermediate element (2) is manufactured in a material which has a neglectable thermal extension at least up to a temperature level, at which the heat treatment is intended to take place. Furthermore, the intermediate element (2) is displaceably positioned on the base element (1).

Abstract: An improved blown film extrusion apparatus is provided. The apparatus includes an annular die for extruding a film tube. At least one tube position transducer is provided and located adjacent to the extruded film tube. The tube position transducer transmits interrogating pulses to the extruded film tube and produces a position signal corresponding to a detected position under the extruded film tube. A bubble position control system is provided for receiving and processing the position signal. A valve is provided for varying a quantity of air within the extruded film tube in response to the bubble position control means. This urges the extruded film tube to a desired position. The apparatus further includes a collapsing frame assembly for receiving the extruded film tube and collapsing it. The collapsing frame assembly includes several frame boards. Typically, two opposing main boards and two opposing side boards are provided.

Abstract: A hybrid injection molding machine that has the capability to draw a decorative or fabric sheet into a mold cavity prior to injection into the mold has opposing male and female mold parts. At least one of the mold parts has an insert formed from a porous metal so that a vacuum may be drawn through the insert in order to draw the fabric sheet into all aspects of the insert cavity so that plastic may then be injection molded into the cavity of the mold.

Abstract: A cold drawing apparatus is interposed in a system for making a fibrous web and has an inlet for a plurality of melt spun continuous filaments, an outlet for the filaments and a pair of side walls extending between said in- and outlets and opposed to and spaced from each other in a transverse direction to define a passage therebetween so that the filaments are cooled and drawn as the filaments pass through the passage defined between the opposed side walls wherein at least one of the side walls is formed with a plurality of crests at predetermined intervals and a plurality of troughs each extending between each pair of the adjacent crests.

Abstract: A thermoforming machine utilizes two clamping frames to advance cut sheets through heating and forming stations, with the clamping frames returned via an overhead path above the oven in the heating station. Pneumatic cylinders arranged about the inner perimeter of the frames are operated to grip the sheet and release the sheets, which are pressurized and released via fluid connections established when the frames are lifted from a transfer bar structure at the loading and forming stations. The clamping frames have pivoted end sections which are engaged by extendible gear posts at the forming station to bend the clamped sheet into greater conformity with the tooling shape prior to forming.

Abstract: A thermoforming station and method for molding a sheet-like plastics material provide to use a bell element including a cover which can be opened on a sidewall in order to provide a large opening for ventilating and cooling the molded plastics material thereby reducing up to 50% the time conventionally required for making a thermoformed evenly cooled product.

Abstract: Methods and apparatus for the processing of a continuous blown film undergoing collapsing in which a plurality of differential elements of the film follow respective streamline paths which are approximately equal in length to the path of the longest streamline thereby substantially equalizing circumferentially varying shape change induced machine direction stresses and reducing the residence time variations within higher thermal energy regions so as to significantly minimize the commonly rather large magnitudes of variations of gauge, energy to break and machine direction lengths of the solidified material. The method and apparatus provide the potential to structure more uniformly the macromolecular arrangements existing within the material and allow the blown film extrusion of higher modulus materials than have heretofore been possible.