Abstract: In the production of kiln fired bricks and hollow structural tiles a substantial loss (about 3.5%-7%) occurs during drying and firing, principally in the bottom layers adjacent the kiln car deck. This can be minimized by reducing the size of the core holes in the bottom rows of bricks, large holes being maintained in the upper layers to reduce the load on the bottom bricks, economising in fuel and clay. The method and apparatus involve use of a longitudinally movable core plug for each hole produced the downstream end portion of which produces small holes while an upstream portion produces large holes, the shape being such that in cooperation with the extrusion nozzle uniform flow and compression are maintained to equalise final column swell sizes as much as possible for both large and small core hole brick preforms.

Abstract: The method of and apparatus for equipping a surface of an article with a profiled gasket, bead or a profiled frame, after appropriate pretreatment of the surface. A thermoplastic elastomer is supplied via an extruder and a heated pressure hose to a heated extrusion nozzle. The nozzle is guided by a robot, and the elastomer is extruded and laid by means of the extrusion nozzle onto the surface. The gasket is applied, for example, to an automobile glazing as a profiled frame along its border.

Abstract: A method of manufacture of a extruded vinyl product to provide a textured stake construction includes an extruder screw and a die having specific structural, and dimensional characteristics and temperature parameters. The extruder screw has a flight depth in the meter zone which is about one half the flight depth in the feed zone and deeper than extruder screws of conventional design. The die includes a frusto-conical section connected to a cylindrical passage. The extruded vinyl stake will have a knobby or textured surface.

Abstract: An apparatus for forming a porous preform that is useable to an optical fiber by extruding a plastifiable material having silica powder as a main component thereof. The apparatus includes an extruding main body having a cylinder and a screw for extruding the plastifiable material from the cylinder and a material passage member connected to the cylinder so as to communicate therewith. The material passage member has a projection member which projects into the material passage member for preventing a lamination of the plastifiable material. The apparatus also includes a molding head connected to the material passage member so as to communicate therewith.

Abstract: A novel extrusion method and apparatus are disclosed for varying the width of an extruded article which employs the use of thermal pins in the extruder die body and does not involve the use of any mechanical manipulation of the die configuration.

Abstract: A method of manufacture of an ultra-high molecular weight polyethylene thin-wall pipe which is uniform in thickness and free from a folded mark. The ultra-high molecular weight polyethylene thin-wall pipe is manufactured by supplying ultra-high molecular weight polyethylene into and melting and kneading, continuously extruding the molten substance of the ultra-high molecular weight polyethylene from a die connected to a screw of the screw extruder to form a cylindrical roughly shaped article, and diametrically expanding the cylindrical roughly extruded article by means of a tapered core and taking up.

Abstract: An extruder head has an inner die member (5) housed in a supporting body (2) and provided with a central duct (6) continuously passed through by a semifinished product (7). An outer die member (9) exhibits a shaped housing (10) defining, in cooperation with the inner die member (5), an outflow port (11) for the mixture to be applied to the semifinished product (7). The shaped housing (10) is defined in a centering element (12) rotatably housed, according to an oblique and incident axis relative to the axis of the central duct (6), within an intermediate collar (13) rotating in the supporting body (2) in coaxial relation with the central duct itself. By rotating the centering element (12), the outflow port (11) moves from a centered position to a maximum-eccentricity position with respect to the central duct (6). The rotation of the intermediate collar (13) modifies the orientation of the common plane containing the axes of the outflow port (11) and central duct (6).

Abstract: An extrusion head for a blow molding machine wherein a movable plunger is slidably mounted in a distributor head which receives a melt at an inlet end of its channel and directs it along such channel to the terminal end of the channel while simultaneously directing portions of it along spiral radial paths to the lower circumferential edge of the distributor head to fill an accumulator chamber which also causes the plunger to recede facilitating the filling of the accumulator chamber. The channel as defined by the adjacent circumferential wall and the curvilinear contour on the distributor head defines a smooth integral flow channel that is curvilinear in cross section.

Abstract: A cast film die used to integrally form closure elements on a film of varying thickness has a removable lower die lip with grooves in the shape of the closure elements and a choker bar located in the manifold of the die to control the amount of extrudate that flows to the grooves.

Abstract: A molding with the cross-section thereof varying in the longitudinal direction, the molding including a support strip; and a protector provided along the length of the support strip so as to bring the molding into contact with a window glass; the support strip including a mounting portion, an outer piece with the height thereof varying along the length of the support strip and a top portion for connecting the mounting portion and the outer piece; and the protector being integrally provided with the outer piece of the support strip at the lower portion thereof by extrusion molding.

Abstract: A flat web of sizable thickness made of thermoplastic can be extruded from an extrusion die without a restrictor bar if a thickness D of a restricting passage is made smaller than a shaping distance A of die lips (4, 5), and if at least one wall of the restricting passage (6) is adjustably designed as an elastic lip (7) by adjusting elements (8), so that thickness D and distance A can be changed at the same time by actuating the adjusting elements.

Abstract: The present invention relates to the integral extrusion of closure profiles and a film through a film die. The present invention provides an apparatus for integrally extruding a film and closure profiles from a single stream of molten material and, consequently, eliminating any joining problems between the film and the closure profiles. The present invention utilizes a removable die lip with removable profile wedges that mount in the die lip and extrude the closure profiles and a film together from a single stream of molten material. In this manner, the closure profiles and the film are integrally formed, and if a new closure profile design is desired, the present invention permits the quick and economical replacement of a removable profile wedge with another.

Abstract: A method of shaping an extruded section of polymer directly onto the surface edges of a glazing or glass plate. In one embodiment, a rotatable plate member having a plurality of calibrated die cross sections is placed in front of the exit orifice of an extrusion die. The plate member is rotated to obtain, an extruded section having different profile cross sections and the flow rate of the polymer through the die is controlled in response to the position of the plate member so that the amount of polymer being fed corresponds to the respective profile section being extruded. In another embodiment, an obturating slide member is placed in front of an extrusion die exit orifice sized to correspond to the largest desired profile cross section. To produce abrupt changes in profile cross section, the slide is moved quickly at predetermined locations along the path of the extrusion die. To produce a continuous transition between profile sections, the slide is moved slowly during extrusion.

Abstract: An improved injection blow molding machine has an melt accumulator or melt metering chamber and a vertically extending oval type die communicating therewith for injecting an elliptical annular parison through the die, which is to be blow molded to produce a hollow double wall type article. The oval type die includes a die housing and a mandrel mounted therein to define a melt passage therebetween having a die lip or opening of a four sided elliptical annular profile at a free lower end of the die. The accumulator is in direct contact with the mandrel, and/or the die housing is enlarged in a horizontal direction at a lower end portion thereof. Preferably the enlarged lower end portion is formed by a plate part fixed to a block part forming an upper portion of the die housing.

Abstract: Fibrous network structures are produced within liquid polymer resins by passing the fiber-containing resin along a channel having a plurality of sets of flow modifying elements which establish a regulated succession of velocity profiles for the principal flow direction and the two directions perpendicular thereto. The individual velocity profiles persist over distances which are small compared to the channel dimension over which they are established and are such that there is substantially no net deviation from the principal flow direction. The velocity profiles superimpose on each other to cause rotation and sliding of the fibers so that a coherent network structure is built up which persists through extrusion dies and molds into the solid state. By means of a large number of touches per fiber the structures thereby established confer efficient mechanical reinforcing properties and enhanced thermal properties on the polymer composition.

Abstract: An improved apparatus providing for uniformity of web thickness. In one aspect, the apparatus includes a plurality of gap-controlling, thermal energy sources, and in heat-exchange communication with the thermal energy sources, an assembly for compensating for temperature variation proximate to the thermal energy sources and across the apparatus width. The thermal compensating assembly includes a heat exchange jacket, and in combination therewith, a heat-exchanging, working fluid that undergoes a phase change in performing its heat exchange function.In another aspect of the invention, the apparatus includes an element disposed along an exit slot-forming lip, that reduces localized thermal gradients along the lip. This element functions as a heat sink and a heat source proximate to the lip gap, and likewise includes a heat-exchanging, working fluid that undergoes a phase change.

Abstract: The present invention provides a novel extrusion apparatus including a flow channel having a modified preland channel that functions as a flow transition zone. The flow transition zone changes the widthwise flow volume of a stream passing therethrough so as to provide for substantially equal flow volume of the stream across the flow channel width as the stream exits from the transition zone.

Abstract: An extrusion die for extruding a thermoplastified synthetic resin, e.g. for a foil-blowing head or a wide-slit nozzle can have its adjustable lip positioned to vary the thickness of the extruded strand by a driver acting on a rod engaging that lip and driven by a step-down transmission from a servomotor which may be a stepping motor.

Abstract: An apparatus for producing extrusions, such as optical waveguide plug prongs or sheaths with a central opening, from a deformable composition, includes a receiving body having an outlet opening and having an interior tapering conically at a predetermined first angle of conicity toward the outlet opening. A flow body is to be inserted into the interior of the receiving body. The flow body has an end portion tapering conically at a predetermined second angle of conicity. The second angle of conicity is smaller than the first angle of conicity. A retainer retains the flow body in the interior of the receiving body. The retainer is resilient in radial direction of the interior of the receiving body.

Abstract: The method and apparatus for producing members (4) of extrudable material, for example a ceramic or synthetic plastic material, use a nozzle (2) composed of a plurality of segments (21 to 25) abutting without gaps and having extrusion ducts (28), segments (21, 22) of the nozzle being moved relative to one another, for example transversely relative to the direction of extrusion. With this method and apparatus it is possible to produce in a single operation members of which the structures, such as open ducts (40), change their relative positions and cross one another.

Abstract: A method of manufacturing a windshield molding by the extrusion process. The molding includes a pair of extruded side molding parts and an extruded upper molding part integral with and extending between the side molding parts. The side molding parts have large thickness portions where water drain channels are formed. The water drain channels have sufficient capacity to guide fluid such as rain water from the outer surface of the windshield.

Abstract: A die assembly (10) for controlling extrudate profile dimension. The die assembly includes a die block (12) having a feed passage (16) for movably supporting a diverter member (13) within the die block, and first and second die block passages (18, 20). The diverter member (13) includes a diverter passage (32) and first and second feed openings (34, 36) interconnected by the diverter passage. One of the first or second feed openings (34, 36) has a larger diameter than the other of the first or second feed openings. The diverter member (13) is movable with respect to the die block (12) for directing extrudate flow via the diverter passage (32) through the second die block passage (20), to thereby vary the profile dimension of the extrudate exiting the die block. The die block (12) additionally includes a disposal passage (22).

Abstract: A foil-blowing head has a nozzle lip which is substantially cylindrical and of an axial length of at least several centimeters and a radial thickness of at least several millimeters. High-force servoeffectors which can be provided with stepping servomotors, speed-reduction transmissions and eccentric drivers, can act upon radial rods to deform the lip and adjust the gap width and the thickness of the foil which is produced to provide continuous thickness correction during foil blowing.

Abstract: Compressible material is compacted into a plug by a device including a housing, solid outer wall, and restricting adjustable portion at an outlet. A root wall is rotated about an axis and conveys the material to be compressed in a channel having solid sidewalls. Without significant extraction of liquid from the material, the material is compressed until discharged in a compacted plug form from the housing outlet. A pneumatic cylinder provides an adjustable force for effecting the compaction adjacent the housing outlet. Examples of compressible materials that may be acted upon in the practice of various industrial processes include wood chips, high consistency paper pulp (cellulose pulp), wax and fibrous waste (for making artificial fireplace logs), and mud and straw (for producing building blocks or bricks).

Abstract: An apparatus for making a noodle base having a construction wherein raw materials of a noodle base are kneaded and stretched in an arbitrary direction by a screw conveyor and extruded as a noodle base having a thick sheet-like form. The extrusion die has a split die structure consisting of a die main body having the upper surface thereof open and a cover body supported rotatably at the base end portion of the die main body and covering the open portion of the die main body, and the cover body is provided with a cover body pushing member for pushing the tip portion of the cover body lest the cover body float up, and for adjusting the height of an extrusion port of the noodle base by adjusting the height of the tip portion of the cover body relative to the die main body.

Abstract: The present invention provides an extrusion apparatus having an improved mechanism for thermally-controlled, lip gap adjustment. The apparatus includes a flow path for a gaseous cooling medium, in which flow path a plurality of temperature-responsive, lip gap adjustment members are disposed. In contact with each such adjustment member is a heating element.

Abstract: A multi-layer, multi-parison extrusion head in which nearly identical parisons are extruded from each extrusion station of the head when operated in an intermittent mode. Resin passages are provided within the extrusion head for supplying each of the resins to each extrusion station with the passages configured in a manner such that the ratio of resin volume for one resin in the passages for a given extrusion station compared to the volume of a second resin in the flow passages to the same extrusion station is the same for all extrusion stations while the volumes of resins feeding each station are not equal. As a result, a relatively simple configuration of passages is provided without requiring all of the passages to be of equal length.

Abstract: An automobile windshield molding is produced by a molding machine having dies. A method of producing the molding includes the step of extruding molding material through a hollow portion formed by the dies. The shape of the hollow portion is changed by moving the dies according to the cross-sectional shape of the molding, thereby widening part of the hollow portion of the dies to increase the thickness of the molding material. One of the dies is projected into the widened part of the hollow portion to form a water drain channel on a large thickness portion of the molding.

Abstract: A bent pipe forming apparatus is provided for extruding and forming a fluid material into an annular member. The apparatus has a central mandrel and a die defining an annular gap between the mandrel and the die. One of the mandrel and the die is supported to move in a direction perpendicular to an axis of the mandrel. The movable mandrel or die is provided, on its outer periphery, with a guide circular surface integral therewith. An inner movable ring having inner and outer circular peripheries eccentric to each other is rotatably fitted on the guide surface. An outer movable ring having inner and outer circular peripheries eccentric to each other is rotatably fitted on the periphery of the inner movable ring. The outer movable ring is provided with an outer circular periphery which is rotatably fitted in a stationary circular guide surface. Driving motors are provided to independently move the inner and outer movable rings.

Abstract: The present invention provides a novel extrusion apparatus that is advantageous for converging rheologically dissimilar streams. Flow transition of a converging stream can be beneficially effected. For instance, a converging stream may be specially contoured by mere mechanical adjustment of a flow-restricting member of the apparatus.

Abstract: An extruder has a screw rotatable in a housing and an extrusion head having an upper part bolted to the housing and a lower part hingedly connected to the housing for movement between a closed operative position and an open position. The upper part of the extrusion head is located above the screw so that the screw can be removed from the housing when the lower extrusion head part is swung to open position and without removing the upper extrusion head part from the housing. The two extrusion head parts define between them a flow passage directed toward the upper roller of a calender. A movable lip on the lower extrusion head part faces, and is spaced from, the upper calender roller to define a variable gap through which extruded material must pass before reaching the narrowest part of the gap between the calender rollers. The lip is either pivoted at an upper edge or is slidable toward and away from the upper calender roller to vary the width of the gap formed between the lip and the upper calender roller.

Abstract: An extruder has a housing, a core centered on an axis, and a sleeve spacedly coaxially surrounding the core and defining therewith an outlet passage. Thus molten material emerges from the passage as a tube. A plurality of radially extending and angularly spaced adjustment screws are threaded into the housing and radially engage the sleeve so that these screws can be screwed in and out to radially displace the sleeve on the housing and thereby adjust the passage. A detecting unit axially downstream of the extruder includes at least one sensor for measuring the thickness of the tube at a plurality of angularly spaced locations and for producing an output corresponding to the respective measured thickness. An adjustment unit including at least one rotary tool engageable with the screws can selectively rotate same and screw same in the housing.

Abstract: An apparatus for controlling the thickness of a film molded by a melt extruding method provided with a plurality of cooling means for cooling the vicinity of a die lip close to a plurality of heating means and with many grooved holes in which the heating means are embedded and provided with air holes at the both ends thereof, whereby the temperature can be freely adjusted to the high and low set values in a short period of time, by which the time loss and material loss can be reduced.

Abstract: An accumulator head for an extrusion-blow molding machine. The accumulator head includes an annular inner sleeve member slidably positioned within an accumulator outer barrel, and a tubular inner body member received within the sleeve member. The sleeve member and body member are adapted to be slidable together within the accumulator barrel to expel collected plasticated material. The inner sleeve member includes a pair of external slots formed in the outer surface that communicate with the accumulator inlet and with respective radially extending flow passageways through the inner sleeve to convey plasticated material from the accumulator inlet into a pair of helical flow channels formed in the accumulator inner body member. The flow channels communicate with an outlet area to convey the plasticated material to an inner accumulation chamber through an annular collector channel and an annular flow passageway that provides an extruded parison having a uniform conformation without flow or separation lines.

Abstract: An improved, low cost, energy efficient extrusion device and method for processing of cellulose, hemicellulose, and like fiber-bearing materials is described which includes a pretreatment extrusion zone and a reaction extrusion zone separated by a pressure sensitive variable die. The method hereof includes the steps of extruding cellulosic material through the pretreatment zone at an elevated pressure and temperature, passing the material into the reaction zone where it is mixed with an acid and is processed at a lower pressure and temperature than in the pretreatment zone, and extruding the material through a final extrusion die. The surging and blowing usually experienced with extrusion of fibrous material is drastically reduced by the unique construction of the extruder die members. The cellulosic material may be hydrolyzed to simple sugars in accordance with the method and apparatus hereof with a minimum of acid degradation of the extrusion equipment.

Abstract: A sidefed die head for forming multiple tubular plastic parisons having a plurality of barrier walls contained in a matrix resin so as to form a plurality of discontinuous, substantially two dimensional barrier walls within the matrix resin which overlap one another so as to form a barrier to permeability. The die head includes a diverter sleeve for each parison to create two counter-rotating circumferential spiral flow channels of resin to form each parison wherein the barrier resin within the matrix resin is stretched to form streaks which are then elongated to form platelets within the matrix resin. The two spiral flow channels form parisons having two concentric layers, each layer having a radial weld line. By positioning the weld lines in each layer circumferentially offset from each other, a single radial weld line through the parison is prevented. The spiral flow channel also increase the impact strength of the container and improves the uniformity in the parison wall thickness.

Abstract: A foil-blowing apparatus has at least one deformable lip defining the annular orifice from which the thermoplastic tube which is blown to form the coil is extruded. The lip can be provided with an array of effectors which, in response to a thickness-profile measuring unit, can radially deform the lip to correct thickness errors. The lip can be under prestress and the radial deformation is effected by measuring the thickness and superimposing a radial force on the prestress.

Abstract: Coextrusion apparatus for varying the outer profile of a generally tubular extrudate formed by inner and outer streams of elastomeric material by varying the annular end opening of an elastic die ring which varies the size of an outer extrusion orifice and consequently the flow of the outer stream of elastomeric material which is deposited on the outer surface of the tubular extrudate. A hydraulically moveable piston is axially slideably mounted for engagement with the elastic die ring and has a wedge-shaped camming surface which moves along the outer surface of the elastic die ring to vary the size of the outer extrusion orifice and consequently the amount of elastomeric material extrudated therethrough. A linear motion detector is connected to the piston to detect the amount of linear axial movement of the piston to provide control signals for controlling the movement of the piston.

Abstract: The invention relates to an apparatus for extruding a polymer profile directly onto the surface of a glass plate and particularly along a peripheral edge thereof. The extruded polymer profile is provided with a sealing and centering lip located on and projecting over the circumferential peripheral surface of the glass plate. The extrusion die has at least one supply channel for the polymer to be extruded. One supply channel or portion thereof leads the polymer material substantially to the portion of the die orifice directed toward the center of the plate. The other supply channel essentially supplies the portion of the orifice directed toward the outside. The supply channel may be provided with a shutoff device which regulates the volume flow. The regulation of the shutoff device takes place as a function of the radius of curvature (R) of the path covered by the extrusion die.

Abstract: A method and apparatus for extruding single or multiple layers of plastic on an electrical conductor without having to adjust the concentricity of layers every time the tooling is changed to make different sizes.

Abstract: An improved adjustable diehead assembly for mounting on a plastic extrusion machine is described. A discharge orifice for a parison of plastic is formed by a mandrel and annular member. The annular member is moveable by a holder assembly perpendicular to axis of the mandrel to adjust the orifice. The holder assembly includes cams which act upon the opposed sections of the outside surface of the annular member to adjust the orifice when first and second screws are tightened. A third screw acts upon the annular member to adjust the orifice. The screws are mounted on a front part of the holder assembly on the diehead to allow adjustment of the orifice even when the extrusion machine is operating.

Abstract: An adjustable extrusion coating die having an inner block member, an outer block member, a mandrel mounted on said inner block member spaced from said outer block member at a predetermined distance, and means for maintaining said predetermined distance substantially constant.

Abstract: Novel method and apparatus is disclosed for forming an integral skin on an extruded honeycomb structure, wherein the skin material is collected in a peripheral area of a die body, is passed through an adjustable flow control gap, and then through a predetermined gap thickness of a skin forming slot so as to then knit with the honeycomb structure extruded by the die prior to being extruded from the die. A plurality of flow control plates having different internal peripheral diameters are provided so as to provide different flow control gaps, as desired. In addition, a plurality of shims having different thicknesses are provided so as to position the mask a given distance away from the die, and thereby control the skin thickness gap. The die may be formed by merely relieving a peripheral portion of a typically automotive catalytic converter extrusion die and providing a trim ring about the relieved portion so as to inhibit the flow of batch material from partially open feed holes.

Abstract: Coextrusion apparatus for varying the outer profile of a generally tubular extrudate formed by merging inner and outer streams of elastomeric material by varying the size of the annular outer extrusion die opening by an axially moveable die ring which varies the flow of the outer stream of elastomeric material which is deposited on the outer surface of the tubular extrudate. The die ring is formed on the end of a hydraulically moveable piston and is axially slideably moved along and is located concentrically about the tubular extrudate. A first annular tapered surface of the die ring moves along a similar tapered surface of a fixed conical-shaped die pin to vary the size of the outer extrusion orifice formed therebetween.

Abstract: Coextrusion apparatus for varying the inner profile of a generally tubular extrudate formed by a first stream of elastomeric material by an axially movable inner die ring which varies the size of an orifice and consequently the flow of a second stream of elastomeric material which is deposited on the inner surface of the tubular extrudate. A compensating ring is axially slidably mounted within the inner die ring and moves generally in an opposite direction to the movement of the die ring to compensate for pressure changes within the second stream of material caused by varying the size of the orifice, to provide an accurately controlled initiation and termination of the material. Pistons are formed integrally on the inner die ring and compensating ring and are located within annular fluid pressure chambers whereby the flow of fluid into the chambers will coordinate the movement of the die ring and compensating ring.

Abstract: A parison forming device is disclosed for forming hollow polymer extrudes of variable wall thickness in either the circumferential or longitudinal directions, or in any combination thereof. The parison forming device consists of a die-head assembly and mandrel assembly, concentrically arranged, creating an annual opening. The inner or outer circumferential perimeter of the annular opening may be selectively modified at specific radial locations through radially displaceable slides positioned about the annular opening. The slides, attached to either the die-head assembly or mandrel assembly, may be actuated during parison formation via hydraulic or other methods so as to provide suitable wall thickness profiles for later finished polymer products.

Abstract: An improved apparatus for controlling a plurality of die lips arranged in the direction of width of an extrusion molding die through which molten resin is extruded in the form of a sheet (or a film) so as to allow the die lips to be displaced back and forth. The apparatus includes a plurality of stud bolts fastened to the die lip with each bolt having a flange portion for holding Belleville springs which are received below the flange portion of the stud bolt. An arrangement is provided to compress the Belleville springs which includes plurality of adjustment bolts.

Abstract: In the discontinuous manufacture of multilayer, co-extruded, hose-like thermoplastics material preforms used in the production of large volume multilayer hollow members in a divided blow mold, at least two different annular shaped material melts are brought together in series within an axially extending annular piston to form a multilayer material melt. An annular flow channel in the piston receives the layers of material melt. The flow channel widens in a funnel-like manner toward an annular storage space. The preform is subsequently ejected from the storage space through an annular nozzle gap by the annular piston moving in its axial direction. The annular piston acts as a co-extrusion head and is pressed upward by the multilayer material melts. In supplying the material melts from extruders into the flow channel of the piston, the material melts flow first in the extrusion direction and then are redirected for flow radially inwardly into the flow channel of the piston.

Abstract: The invention concerns apparatus for molding thermoplastic tubing having solid annular ribs. The apparatus is of the type where a tubular mold is defined by cooperatively interengaged mold block of a pair of mold assemblies. An annular extrusion orifice for the tube extends into the mold tunnel and tubing is extruded about a mandrel. The invention provides an accumulator chamber in the region of the extrusion nozzle to provide for pressure differences which build up at that point. Thus, the effective volume of the accumulator chamber can compensate for the varying requirement for the thermoplastic material resulting from the varying radial wall thickness.

Abstract: The present invention provides an extrusion apparatus having an improved mechanism for thermally-controlled, lip gap adjustment. The apparatus includes a flow path for a gaseous cooling medium, in which flow path a plurality of temperature-responsive, lip gap adjustment members are disposed. Structurally associated with each such adjustment member is a heating wire.