Abstract: A method for forming an object made of a polymeric material, wherein the polymeric material has a melting temperature (Tf), comprising the following steps: melting the polymeric material; cooling the polymeric material below the melting temperature (Tf); extruding the polymeric material into a tubular shaped body (H); inserting the tubular body (H) into a mould (60) having an internal cavity; closing off the tubular body (H) at a first end thereof; blowing air into the tubular body (H) through a second end, in order that the tubular body (H) adheres to the internal cavity of the mould (60).

Abstract: A blow mold high-pressure switching step in a blow molding process of an injection stretch blow molding machine is arranged at the first half portion of the blow molding process, to shorten the injection molding process and improve the moldability. The blow mold high-pressure switching step 61B3 of increasing a mold clamping force for blow molds which have been closed in a blow molding process 61B is configured to be performed at a timing within a time from the start of the upper/lower mold opening step 62A1 for opening upper and lower molds in the injection molding process 62A to release a preform 3P to the completion of the injection mold high-pressure switching step 62A3 for increasing the mold clamping force for the closed injection molding mold.

Abstract: An innovative plant (10) for the production with the “spun bonding” technology or similar of a web (V) of non-woven fabric, comprising: a melting station (11) suitable for receiving and melting a polymeric base material (MR), an extrusion bar or head (12) with a plurality of extrusion or drawing nozzles (12a) adapted to receive from the melting station (11) the polymeric material (MR) in the molten state to produce a plurality or bundle of continuous filaments (FF); a conveyor belt (13) adapted to advance along a direction of advancement (A) and to receive from the above the continuous filaments (F), produced by the extrusion nozzles (12a), so as to form a web (V) of non-woven fabric; and consolidation means (14) designed to consolidate the non-woven web (V) formed on the conveyor belt (13); wherein the plant (10) is characterized by a special structure (20) comprising a base platform (21), rotatable (f, f?, f?) around a respective vertical rotation axis (X), and wherein the melting station (11), suitable for

Abstract: A blown film line and process for making blown film, including an annular extrusion or coextrusion die, a plurality of nip rollers at a location remote from the annular die, a blown film bubble extruding from the annular die and traveling toward the nip rollers along a traveling path, an air cooling apparatus in the vicinity of the annular die, and a water cooling apparatus located downstream from the air cooling apparatus along the traveling path. The water cooling apparatus includes a wet porous material in direct contact with the blown film bubble and surrounding an outer circumference of the blown film bubble. The wet porous material continuously wipes the blown film bubble with water as the blown film bubble moves along the traveling path.

Abstract: A polytetrafluoroethylene tube is provided and has a thickness of 0.1 mm or less, a tensile elongation at break of 350% or more, and a melting energy of 0.6 J/g or more which is calculated from an endothermic peak at 370° C.±5° C. in a procedure of increasing a temperature in differential scanning calorimetry (DSC).

Abstract: The present invention relates to an external cooling system for a molten film tube produced by a blown film tubular extrusion process, comprised of one or more enclosures with one or more respective cavities that directly receive a portion of cooling gas emanating from one or more associated cooling elements. Each enclosure includes a port containing a variable exhaust device and optional flow buffer, acting to maintain a pressure differential between the cavity and an adjacent inside volume of the molten film tube, adjustable to optimize molten film tube stability cooling element efficiency and spaced apart dimension between cooling elements. Additionally, at least one cooling element is provided, comprised of a divergent cooling element with a divergent cooling interface containing a cooling gas deflector spaced adjacent to the molten film tube and providing an expelled cooling gas.

Abstract: The present invention provides polylactic acid particles, which are formed in a continuous matrix phase from a polylactic acid resin and have a particle diameter of 1 to 100 ?m. In a differential scanning calorimetry (DSC) curve of the polylactic acid particles, derived from the analysis by DSC using a temperature rise of 10° C./min, a peak of the cold crystallization temperature (Tcc) is shown at a temperature between the glass transition temperature (Tg) and the melting point (Tm). The polylactic acid particles have an aspect ratio of more than or equal to 1.00 and less than 1.05 and a roundness of 0.95 to 1.00. The polylactic acid particles have a flow time of 20 to 30 seconds.

Abstract: A headliner for a vehicle includes a substrate that attaches to, and covers a roof panel, the substrate defining a groove on a first side formed around an entirety of a periphery of an area of the roof panel, wherein the groove is continuous around the periphery. A light emitting material is disposed within the groove formed in the substrate and is uninterrupted around the periphery within the groove.

Abstract: A pulsating corrugator is provided with at least one secondary mold block that is selectively used for forming a spigot connection as the corrugated or ribbed pipe is formed. Preferably, the primary mold blocks used to form the corrugated pipe are also used to assist in further cooling of the formed spigot connection once released from the secondary mold block. The corrugator also includes a controller used to provide different air pressure as the mold blocks move past extrusion outlets of an associate extruder.

Abstract: The invention relates to a blown film extrusion device with a blow head and with an insulation, which comprises a heat resistance for thermal insulation of the blow head in relation to the outer ambient air, wherein the blown film extrusion device comprises elements for controlling the heat resistance.

Abstract: A calibration device for the extrusion of profiles from plastics is provided. The calibration device comprises at least one tank calibrator with an opening and a running surface for the extruded profile, which can be arranged in a vacuum tank with cooling water and via whose outer surface the heat of the extruded profile can at least partly be transferred to the cooling water. The at least one tank calibrator includes at least one cooling channel for cooling the running surfaces and the axial length of the tank calibrator at least corresponds to the height and/or the width of the nominal dimension of the profile.

Abstract: This invention relates to methods for forming a polymer, including continuously depositing a polymer extrudate that is above its glass transition temperature onto a lower molding surface of a first mold in a manner that reduces shear stress in the polymer extrudate, heating the lower molding surface to maintain the polymer extrudate above the glass transition temperature, applying an upper molding surface of a second mold to at least the exposed upper surface of the polymer, allowing the polymer to transition to below the glass transition temperature while within or between the upper and lower molding surfaces, and providing heat sinks spaced relative to each other through the pressure forming zone, wherein a heat sink more advanced through the pressure forming zone is controlled to a lower temperature to progressively reduce the temperature of the polymer as it advances through the pressure forming zone.

Abstract: Systems, devices, and methods are described for extruding materials. In certain embodiments, one or more hollow billets are loaded onto an elongate mandrel bar and transported along the mandrel bar to a rotating die. The billets are transported through fluid clamps, which engage the mandrel bar and provide cooling fluid to the mandrel bar tip, and through mandrel grips, which engage the mandrel bar and prevent the mandrel bar from rotating. One or more press-rams advance the billets through a centering insert and into the rotating die. A quench assembly is provided at an extrusion end of the extrusion press to quench the extruded material. A programmable logic controller may be provided to control, at least in part, operations of the extrusion press system.

Abstract: A device for calibrating membrane tubes which are extrudable by an extrusion die includes a ring along an interior wall with which the extruded membrane tube can be guided, and a cooling liquid supply source which can be used to provide a cooling liquid which can be conveyed to between the interior wall and the membrane tube. The ring includes at least one open chamber in the region where the membrane tube exits the ring, with at least one opening of the open chamber facing the membrane tube and being sealed with at least one permeable webbed piece. A vacuum can be applied to the chamber.

Abstract: Systems, devices, and methods are described for extruding materials. In certain embodiments, one or more hollow billets are loaded onto an elongate mandrel bar and transported along the mandrel bar to a rotating die. The billets are transported through fluid clamps, which engage the mandrel bar and provide cooling fluid to the mandrel bar tip, and through mandrel grips, which engage the mandrel bar and prevent the mandrel bar from rotating. One or more press-rams advance the billets through a centering insert and into the rotating die. A quench assembly is provided at an extrusion end of the extrusion press to quench the extruded material. A programmable logic controller may be provided to control, at least in part, operations of the extrusion press system.

Abstract: Apparatuses for expanding tubing and methods of use are provided herein. An exemplary process may include heating tubing to an expansion temperature, expanding the heated tubing within an expansion chamber by injecting a first fluid within the heated tubing to expand the heated tubing, and constraining expansion of the heated tubing within the expansion chamber by introducing a second fluid between an outer sidewall of the heated tubing and an inner sidewall of the expansion chamber.

Abstract: A system for manufacturing an irrigation pipe comprises an extrusion unit, a calibrator unit, a cooling unit for cooling the irrigation pipe in a cooling liquid, and a traction unit for drawing the irrigation pipe in the cooling unit. The cooling unit comprises a device for detecting holes in the wall of the irrigation pipe and arranged for being immersed in the cooling liquid. The device for detecting holes comprises at least one optical transmitter and at least one optical receiver which define an optical barrier. The device is arranged so that the holes in the irrigation pipe located below the device produce gas bubbles which modify the optical barrier.

Abstract: An apparatus for embossing a web having a static gas pressure plenum and a forming structure disposed in contact to the static gas pressure plenum. The static gas pressure plenum provides a static gas pressure of from about 0.1 MPa to about 25 MPa.

Abstract: A mobile plastics extrusion plant 10 for manufacturing an extruded plastics product in a remote location. The mobile plant 10 comprises the following components: a transportable container 16 for storing raw plastics material prior to extrusion, and a transportable extruded product forming assembly (in the form of a die and former assembly 12) for forming an extruded plastics product from the raw plastics material. The mobile extrusion plant 10 further comprises a transportable delivery system 18 for delivering the raw plastics material from the transportable container 16 to the die and former assembly 12 whereby, in use, the entire plant can be transported to a remote location and operated to manufacture an extruded plastics product.

Abstract: A gas assisted co-extrusion apparatus includes a co-extrusion die in communication with an extruder. A nozzle that is defined by a bore in the co-extrusion die extends about a nozzle axis to a nozzle exit of the co-extrusion die. An injector extends through the bore of the co-extrusion die along the nozzle axis. The injector and nozzle together form a dough into a rope that is tubular with a wall portion and an inner cavity surrounded by the wall portion as the dough is extruded out of the nozzle exit and about the injector. A compressed gas source provides a compressed gas out of an injector outlet and into the inner cavity of the rope to radially stretch the wall portion of the rope as the rope is dispersed from the injector. The co-extrusion die is spaced from the extruder to define a void therebetween. A delivery system delivers an entrainable material to the compressed gas in a pipe. The pipe is connected to an injector inlet of the injector in the void.

Abstract: An apparatus for the continuous production of a twin wall pipe has mold block halves supplied in pairs to form a mold, and a pipe head, which has an external nozzle for the extrusion of an external hose and an internal nozzle for the extrusion of an internal hose. A support air and venting channel which is annular-cylindrical and concentric with respect to the center longitudinal axis of the pipe head opens out between the external nozzle and internal nozzle.

Abstract: Processes for manufacturing hollow structures such as spars for helicopter rotor blades, fixed wings for aircraft, and other aerostructures can include the provision of a path for gases to exit the material from which the spar is formed as the material is heated and cured, to help eliminate voids within the material caused by the presence of such gases.

Abstract: An apparatus for producing thermoplastic corrugated pipes may include an extrusion device with an extruder and an extrusion die device and a corrugator device with traveling mold jaws. The extrusion device and the corrugator device are positionally movable in relation to one another, for example for adjustment. The extrusion device is positionally movable in relation to the corrugator device in a horizontal plane, while the corrugator device is movable exclusively in height here.

Abstract: An extrusion line for producing plastic profiles, preferably plastic pipes, comprising at least one extruder, one die, one calibration means and further following devices. The die has at least one aperture, and an extraction means arranged in front of the die as viewed in the extrusion direction, and the die consists of a plurality of functional regions with separate melt channels. Furthermore, the invention relates to increasing the cooling performance of an extrusion line for extruding a plastic profile, in particular a plastic pipe, which comprises the following steps, a) melting plastic in an extruder, b) shaping a plastic strand and feeding the plastic strand to a die, c) shaping a plastic profile by means of the die, and d) calibrating and curing by cooling the profile, the profile being cooled in the interior in addition to outer cooling.

Abstract: An optofluidic lithography system including a membrane, a microfluidic channel, and a pneumatic chamber is provided. The membrane may be positioned between a pneumatic chamber and a microfluidic channel. The microfluidic channel may have a height corresponding to a displacement of the membrane and have a fluid flowing therein, the fluid being cured by light irradiated from the bottom to form a microstructure. The pneumatic chamber may induce the displacement of the membrane depending on an internal atmospheric pressure thereof.

Abstract: A system is disclosed for manufacturing multi-wall corrugated polymer pipe. The system includes an extruder configured to co-extrude concentric annular tubes; a corrugator configured to form the concentric annular tubes into a dual-wall pipe having a smooth wall and a corrugated wall; a cross-head die configured to extrude an outer wall of pipe onto the corrugated wall of the dual-wall pipe; a vacuum punch configured to penetrate the outer wall of pipe and draw a vacuum between the corrugated wall and the outer wall, such that the outer wall of pipe deforms inward toward the corrugated wall of pipe between bell and spigot portions of the corrugated wall; and a cutter configured to cut the pipe into sections where the vacuum punch deformed the outer wall between the bell and spigot portions of the corrugated wall. A method of manufacturing multi-wall corrugated polymer pipe is also disclosed.

Abstract: A shape adjusting mechanism for an extrusion molding machine includes a shape adjusting member, a blow-in mechanism, and a discharge mechanism. The shape adjusting member comes into contact with an inner circumferential surface of a molten substantially cylindrical resin extruded and transported from a ferrule provided to an extrusion molding machine, and adjusts the shape of the substantially cylindrical resin. The blow-in mechanism blows a gas into the substantially cylindrical resin transported between the ferrule and the shape adjusting member. The discharge mechanism discharges to the outside the gas in the substantially cylindrical resin transported between the ferrule and the shape adjusting member.

Abstract: Injection stretch blow molded (ISBM) articles and methods of forming the same are provided herein. In one embodiment, the ISBM articles generally include a propylene based random copolymer having a molecular weight distribution of from about 9 to about 20. In another embodiment, the ISBM articles generally include a propylene based random copolymer formed from a Ziegler-Natta catalyst including a succinate internal donor.

Abstract: A corrugator device for shaping thermoplastic corrugated pipes from a tube of molten plastics material emerging from an extrusion device may include molding jaws, grippers for returning the molding jaws from the end of a molding section to the start of the molding section, and a mold release device. The mold release device is arranged at the end of the molding section, and has a motor-driven rotary disk for interacting with the pair of molding jaws. The pair of molding jaws, which has reached the end of the molding sections, is moved apart by means of first and second drivers formed on the motor driven rotary disk.

Abstract: A device for producing a drip irrigation tube comprising an extrusion apparatus for extruding a tube body made from a thermoplastic synthetic material is provided. Metering elements are inserted in the extruded tube body and connected to the tube body. A calibrating device adjusts the tube body to the desired outer shape, and a cooling device cools the tube body. Outlet holes are made in the tube body in the vicinity of the metering elements to permit the passage of water from the tube body during use. A control unit for controlling the device for making outlet holes is provided, and a sensor which upon lifting of the roller during passage of a metering element emits a signal to the control unit which emits a signal to the device for making outlet holes.

Abstract: A corrugator device for shaping thermoplastic corrugated pipes out of a molten plastic tube issuing from an extrusion device may include moving molding jaws which circulate in a linear molding section and are arranged in paired successive relationship in the molding section forming a molding passage. The pairs of molding jaws may be formed from left-hand and right-hand molding jaws and between them enclose a cylindrical mold cavity to form the molding passage. The device may include a gripper device for guiding the molding jaws from the end of the molding section back to the start of the molding section, and having grippers respectively for the left-hand and the right-hand molding jaws, each with a separate guide and drive device.

Abstract: A fluid reticulation system for a composite component production assembly, the production assembly including at least one pressure chamber (25) having a chamber wall (21) locatable adjacent a composite lay-up or mold, at least a portion of the chamber wall (21) being resiliently deformable, the fluid reticulation system being locatable within the inner volume of the pressure chamber (25) and including means (5) for distributing fluid towards an inner surface (22) of the chamber wall as the fluid enters the pressure chamber.

Abstract: The present invention provides an apparatus for inflation extrusion molding of pressure-sensitive adhesive sheet, including: one or a plurality of extruders; a die into which one or a plurality of resin materials are respectively introduced and which extrudes from an ejection opening the resin materials into an inflated cylindrical shape having a predetermined diameter in accordance with an inflation method; and two stabilizers facing each other at a predetermined angle so as to upwardly approach each other, and defining a space therebetween through which the cylindrically-shaped resin materials extruded from the die are passed to be deformed into a pressure-sensitive adhesive sheet in a flattened elliptical shape having a predetermined width, in which the stabilizers each have a plurality of air floating portions each of which blows air toward the resin materials; and the stabilizers rotate in one direction around the central axis of the cylindrically-shaped resin materials.

Abstract: The invention under consideration concerns a device for the production of corrugated pipes made of thermoplastic, in which mold jaws, which complement each other in pairs, are conducted jointly in a cycle along a mold section that leads away from an extruder head; they are moved apart at the end of the mold section and are returned to its beginning separately from one another with a mold section device for the movement of the mold jaws along the mold section, which has a supporting table with drive means for the mold jaws on the mold section, and with a return conveying device for the return conveyance of the mold jaws from the end of the mold section to its beginning, which has an outlet assembly to move apart the mold jaws at the end of the mold section and/or an inlet assembly to move in the mold jaws at the beginning of the mold section.

Abstract: A system for controlling the dimensions of an extrudate exiting an extruder and for compensating for the variations in the extrusion rate of the extruder, expansion rate and rate of travel of the extrudate through sizing devices by changing the speed of an extrudate puller device, includes an extruder which extrudes the extrudate; a conveyor system comprising rollers and a series of sizing devices; a puller device for pulling the extrudate through the sizing devices; and a laser proximity measuring device to assist the system in keeping the desired shape of the extrudate. The laser proximity measuring device includes at least one pair of optical non-contact displacement transducers, a real time processor, and an interactive touch screen display unit. The transducers emit a laser beam which provides a laser point on the side of the extrudate.

Abstract: An extrusion die configured to have an interior chamber sealed from the atmosphere is disclosed. The extrusion die includes an extrusion die head disposed at a downstream end of the interior chamber; and a vacuum seal disposed at an upstream end of the interior chamber; wherein the vacuum seal is configured to selectively form a seal between the extrusion die and a product disposed in the interior chamber. The vacuum seal includes an annular sealing surface disposed at an inner diameter of the vacuum seal; a hollow, interior chamber; and a plurality of bellows disposed between the annular sealing surface and the extrusion die; wherein the vacuum seal is configured to selectively form a seal between the extrusion die and a product disposed in the interior chamber. A method of selectively sealing an end of an extrusion die is also disclosed.

Abstract: A system and controller for positioning an adjustable sizing cage for use with a blown film extrusion apparatus. A cage sizing subsystem is used to position the cage relative to the film tube. At least two non-contact sensors arranged on the sizing cage to provide signals to an automatic controller, which in turn positions the sizing cage a predetermined distance from the extruded tube. Two different modes of operation are provided for the controller when the size of the tube is to be changed: a forecast mode in which relatively large cage movements of the cage are made, and a contact mode in which the cage is maintained either in contact with the extruded tube, or at an operator selected distance from the extruded tube.

Abstract: A rotary die head for a film blowing machine for use with a starch-based biodegradable material including a core mould and an outer body. The core mould includes a spiral core mould sleeved on a center pivot and a rotary core mould fixed on the center pivot, jointed with each other. A motor drives the center pivot and the rotary core mould to rotate. The outer body includes an inner die casing sleeved on the spiral core mould, an outer die casing fit with the inner die casing, and a mouth die casing. The inner die casing, the mouth die casing, the spiral core mould, and the rotary core mould form a material flow and molding channel consisting of a herringbone feed-in slot, spiral conveying slots, an annular gap buffer zone, a tapering cone passage, an annular loosing cavity, and a final molding gap in turn from bottom to top.

Abstract: A method of forming a shaped thermoplastic sheet includes providing a mold apparatus that includes, a first mold portion having an interior mold surface having a plurality of perforations and a perimeter edge. The mold apparatus further includes at least one sheet retainer having an upper surface having a plurality of perforations and a longitudinal axis that is oriented along at least a portion of the perimeter edge of the first mold portion. Each sheet retainer is reversibly and controllably: positionable along an x-, y- and/or z-axis relative to the perimeter edge; and rotatable around its longitudinal axis, toward and/or away from the perimeter edge. A heated thermoplastic sheet is formed and contacted (while at a thermoformable temperature) with the interior surface of the first mold portion and the exterior surfaces of the tubular sheet retainers. Reduced pressure is drawn through the perforations of the sheet retainers thereby retaining a portion of the heated thermoplastic sheet thereon.

Abstract: An apparatus for the manufacture of a thermoplastic blown film is provided having a blower head for extruding a film tube of a thermoplastic material. An annular ring is provided for blowing a cooling gas on an outside surface of the film tube to solidify the film tube. This cooling gas is directed in a flow direction parallel to a wall of the film tube. The cooling gas is drawn off the tube by means of a suction ring positioned around the tube prior to flattening the tube to form a film tube.

Abstract: The invention relates to a process and a device for the continuous production of an extrudate from finely divided plant material and a thermoplastic material, in which, as viewed in the extrusion direction (E), firstly the finely divided plant material and then the thermoplastic material are fed to an extrusion device (1), which is embodied as a twin-screw extruder, the fed-in materials are mixed with one another, degassed and jointly extruded from the extrusion device thus forming the extrudate (6), and the plant material is embedded in the thermoplastic material, wherein the plant material and the thermoplastic material are fed into the extrusion device at a common position or two directly successive positions, the thermoplastic material is plastified in a separate plastifier extruder (4) before being fed into the extrusion device and is fed from said extruder to the extrusion device (1) in a plastified state, and the plant material is then degassed together with the thermoplastic material.

Abstract: An air ring with increased-control over the gauge uniformity of blown plastic film in a film extrusion device. The air ring includes a generally annular plenum, an annular orifice for discharging cooling air against an extruded plastic tube passing through the air ring, and a flow path for cooling air between the plenum and the annular orifice. The air flow path is segmented along a circumference of the annular plenum, the segments including a material with high heat conductivity and guiding the air from the annular plenum to the orifice. Heating elements are provided for individually and selectively heating the segments of the air flow path such that the temperature of the cooling air discharge against the extruded plastic tube can be locally varied.

Abstract: The pipe molding system includes a separable cooling plug and an automatic procedure to alleviate problems associated with excess plastic continuing to extrude after a sudden shutdown of the extrusion system. The separable cooling plug and shutdown procedure includes accommodating any excess plastic in a created void between the cooling plug and the extruder. This arrangement simplifies removal of the excess plastic and reduces the time required to return the equipment to normal production. Preferably, a controller monitors operating conditions of the system and automatically releases the cooling plug based on the monitored operating conditions.

Abstract: Device for extruding hollow strands from thermoplastic material, with an extruder head, having a mandrel, and a calibrating device, for making a dimensional change while production is in progress, and with a radially adjustable inlet, at least one Ranque vortex chamber being formed in the mandrel, the cooling air outlet of which chamber leads into a cooling tube, which extends as an axial extension of the mandrel through the inlet of the calibrating device and has a cooling air outlet opening out into the calibrating device. This device achieves the object of providing a device with which effective interior cooling is achieved in calibrating devices designed for making a dimensional change while operation is in progress.

Abstract: Numerous aspects concerning a blow film system are improved by the present invention.

Abstract: A device is suggested for calibrating an extruded plastic profile (1) having a shaping extrusion die (3) and having a framework (6) which is displaceable in the longitudinal direction of the plastic profile (1) in relation to the extrusion die (3), which has a cooling tank (5) and, between the cooling tank (5) and the extrusion die (3), a dry calibration apparatus (4) which is replaceably attached to a carrier (12) and is connectable on one hand to supply lines for a coolant liquid feed and removal and on the other hand to a partial vacuum. To obtain advantageous mounting conditions, it is suggested that the carrier (12), which is adjustable in relation to the cooling tank (5) in the longitudinal direction of the plastic profile (1), form a distributor, connected to the supply lines (16, 17), having line transitions (25) for the coolant liquid and the partial vacuum in the placement area of the dry calibration apparatus (4), which is provided with corresponding line transitions.

Abstract: A film die for the production of tubular film made of thermoplastic synthetics has at least one feed channel for the synthetic fused material which ends in a ring-shaped discharge nozzle with an interior and/or exterior cooling ring that is adjusted to the diameter of the extruded synthetic tube, in which physical parameters of the air blown onto the extruded film tube can be variably changed sector by sector. The film die is divided into sections, in which the temperature is individually variable, and/or additional bores are arranged across the circumference of the film die, which are essentially aligned vertical to the exterior cooling ring, whereby air of variable temperatures can be blown from them, the physical parameters of which are variable. The film die has at least one control unit that controls or operates the various measures for influencing the film thickness.

Abstract: An air ring for supplying cooling air to a hot extruded plastic film after extrusion from an annular extrusion die has an annular body surrounding the emerging tubular plastic film. The annular body has an annular plenum chamber receiving air from an external source. A circumferentially extending series of separate air passages receives air from the plenum chamber and extends radially inwardly to respective separate orifices adjacent to and surrounding the tubular film. Separate adjustors individually control the air flow from the plenum chamber to respective air passages and associated orifices, whereby air flow from each orifice impinges on a discrete circumferentially extending portion of the tubular film substantially independently of air flow from other orifices. Each adjustor controls air flow to only one orifice. The plenum chamber also supplies air through an annular passage in the annular body to an annular orifice adjacent to and surrounding the tubular film.

Abstract: The invention relates to a calibrating plate for an extrusion die for producing plastic profiles, comprising a substantially plate-shaped basic body (21), in which an opening (22) for guiding and calibrating the plastic profile (23) to be produced is provided, with at least one insert part (1) made of a material with high hardness being inserted into the basic body (21), which insert part comprises at least one holding section (2) and a shaping section (3), with both the holding section (2) as well as the shaping section (3) being formed partly as cylindrical surfaces with generatrices parallel to the extrusion axis (6), and with the insert part (1) being held in the axial direction in the plate-shaped basic body (21) by a delimiting stop (5).

Abstract: In a method for manufacturing a double-walled, thermoplastic tube with a connecting sleeve, which enables precise and complete molding of the connecting sleeve by simple means, it is provided that a) a first tube (1) is extruded into a mold tunnel (4) comprising at least one row of molds (5) guided on a path, b) the first tube (1) is given a corrugated shape in at least one first section and expanded into a connecting sleeve in at least one second section, c) a second tube (6) is extruded into the first tube and pressed against the corrugation troughs (8) of the first tube (1), d) while the first tube (1) is being given a corrugated shape and the second tube (6) extruded into the first, the space (A) between the two tubes (1, 6) is subjected to a pressure p1 that is above atmospheric pressure, e) the space (A) between the two tubes (1, 6) is subjected, at a specified time before or after expansion of the first tube (1) into a connecting sleeve, to an essentially constant pressure p2?p1 above atmospheric press