Abstract: Disclosed herein are a helical gear forging apparatus wherein a forming introduction portion thereof, used to form gear teeth of the helical gear, is variable in shape on the basis of the desired helix angle of the gear-teeth so as to constantly keep a predetermined outer diameter of the formed gear teeth, thereby enabling easy forming of the helical gear irrespective of a variation of the helix angle, and a forging method using the same. The forging apparatus comprises a gear die having a gear teeth forming section defined at an inner circumference thereof for forming gear teeth of the helical gear, a collar die integrally formed at an upper end of the gear die, a lower die located below the gear die, a punch located above the collar die and adapted to push a stock into the collar die, and a knock-out located below the lower die and adapted to discharge the molded stock to the outside.

Abstract: A method for manufacturing a ring-shaped magnet includes arranging, in a penetrating hole formed in a die, a mandrel having a cylinder tip portion of a diameter d1, a cylinder base end portion of a diameter d2, provided d1<d2, and a taper portion positioned between the cylinder tip portion and the cylinder base end portion. The penetrating hole includes a first penetrating hole portion of a diameter D1, a second penetrating hole portion of a diameter D2, provided D1<D2, and a tapered hole portion of a positioned between the first penetrating hole portion and the second penetrating hole portion. The cylinder tip portion is loaded with a preform, and plastic-working is performed on the preform in a gap formed by the penetrating hole and the mandrel by pressing the preform with a pressing punch.

Abstract: Equipment for cold-drawing a metal wire. The equipment includes a succession of a sleeve with a cylindrical hole and a threading die with a conical hole. The sleeve is inserted into a support and terminates with an extension inserted into the conical hole of the threading die. The support has a first annular projection and the threading die has a second annular projection coupled to the first projection so as to keep the sleeve and the threading die in position.

Abstract: It is an object to realize and establish new extrusion technology for manufacturing a light-metal hollow member (product) having excellent mechanical properties with constant stability and also efficiently manufacturing the product having a strength satisfying a required level at low cost, by using a hollow die such as a bridge die. The object is achieved by dividing and joining/welding a light-metal material with a hollow extrusion die and then extruding the light-metal material to form in a desired cross-sectional shape through a die opening, wherein the strain level applied to the light-metal material after the joining/welding is maintained at 1.8 or more and the extrusion is performed.

Abstract: To provide a diamond compact die semi-manufactured product and a diamond compact die that do not crack during die processing. A diamond compact die semi-manufactured product includes a diamond compact and a holding ring. The holding ring is a cylinder composed of a tungsten alloy, and the inner diameter thereof is tapered. The diamond compact is tapered so as to fit to the taper of the cylinder and the diamond compact is press-fitted to the holding ring. For lower cost production, the tapered face of the diamond compact is formed by electric spark machining. The tungsten alloy contains 90% to 97% by weight of tungsten and 3% to 10% by weight of nickel.

Abstract: A tool pack assembly for use in the manufacture of two piece metal can bodies. The tool pack assembly of the present invention is constructed and arranged for use in a body maker assembly to form parts of metal cans. The tool pack assembly of the invention includes an improved die module structure. The improved die module includes compressible dampening structures to thereby float a die element to center and align the metal body with the die element.

Abstract: An extrusion die for manufacturing a tube with a plurality of small hollow portions arranged in a width direction of the tube, includes a female die for defining an outer periphery of the tube and a mandrel combined with the female die. The mandrel includes a body portion and a comb-shaped portion protruded from the body portion, the combe-shaped portion including a plurality of columnar portions desposed in a width direction of the comb-shaped portion at certain intervals. An outer periphery of a tip end portion of each of the plurality of columnar portion constitutes a bearing portion for defining an inner periphery of each of the plurality of small hollow portions of the tube. Each of the plurality of columnar portions has outside surfaces opposed in a thickness direction of the comb-shaped portion, and at least one of the outside surfaces has an inwardly dented portion behind the bearing portion, the inwardly dented portion constituting an extrusion material filling space.

Abstract: An apparatus and method are provided for angularly extruding a workpiece through a die to form blanks and articles having refined grain structure. The die is also used to form the workpiece to a desired shape, such as a cylinder. The angular extrusion method can be used in place of some heat treatments, thereby lowering the cost and time for manufacturing articles. The method is compatible with materials with high strength-to-weight ratios such as aluminum, titanium, and alloys thereof. The blanks can be used to form articles having favorable mechanical properties such as strength, toughness, formability, and resistance to fatigue, corrosion, and thermal stresses.

Abstract: An apparatus for swaging an end of a tubular (22) is described as comprising a swaging head (17) for providing the swage to the end of the tubular (22). The swaging head (17) has two or more formations (22A, 22B) provided thereon to permit swaging of differing diameters of tubular ends. The apparatus may comprise a stop plate (5, 9) for abutment against the other end of a tubular (22) where the swaging head (17) and the stop plate (5, 9) are movably coupled to one another. The apparatus may have a clamping device (4) for clamping the tubular (22), where the clamping device is split into at least three part-circular clamping segments (30) which clamp around the outer circumference of the tubular to permit it to be swaged. The clamping device (4) may have a plurality of teeth (35) for gripping the outer surface of the tubular (22), and a plurality of grooves 36 formed between the teeth (35).

Abstract: Process for the wall ironing of a product in sheet form, which is formed from a metal sheet coated on at least one side with a layer of plastic, the wall-ironing tool comprising a forming surface which the product with a plastic coating layer moves along during the wall ironing, and the forming surface being at an entry angle with respect to the direction of movement of the product, whereby the entry angle varies over the length of the forming surface, in the direction of movement of the product past the forming surface, this entry being smaller in a starting zone of the forming surface than in the subsequent zone thereof.

Abstract: A split die includes a plurality of die pieces which can be assembled into a die nib. The die nib defines a central wire forming passage which has a cross section of a substantially rectangular shape or a square. The cross section of the wire forming passage is progressively smaller such that the wire forming passage has a predetermined approach angle. Each of the die pieces has a passage segment of a generally triangular shape to partially define the wire forming passage. The die piece has a pair of side lines each passing a point on an axial center line of the wire forming passage.

Abstract: The tungsten/heavy metal alloy is suitable for tools such as extrusion dies and extrusion mandrels for the hot-forming of copper and copper alloys. The novel alloy consists of 80 to 89.9% by weight of tungsten, 2 to 7% by weight of chromium, and a remainder of binder metal. The use of the novel alloy primarily results in a considerably reduced formation of grooves on the surface of the forming tools.

Abstract: An extrusion die for a hollow member includes: a male die for defining a plurality of hollow portions of the hollow member, the male die including an annular base portion and a bridge portion bridging the annular base portion; a female die for defining an outer peripheral portion of the hollow member, the female die being fitted in the annular base portion; and a mandrel having a plurality of forming protrusions, the mandrel being inserted and held in a mandrel holding slit formed in a center of the bridge portion in a fore-and-aft direction. The mandrel includes a mandrel main portion divided into a plurality of divided members and a plurality of rigid pins each arranged in a fore-and-aft direction of the mandrel main portion, and wherein the rigid pins are pinched by and between the divided members of the mandrel main portion with tip portions of the rigid pins protruding from an front end of the mandrel main portion, whereby the tip portions constitute the forming protrusions.

Abstract: The invention concerns a device and a method for continuous pressing of a plastically deformable blank into a three-dimensional section with a predetermined cross-sectional area, comprising a substantially cylindrical, fixed die, an opening formed in the die, through which the plastic blank is intended to be pressed, and at least one rotary die arranged adjacent to the opening, the rotary die having one or more recesses in its peripheral surface for forming the blank, during the rotation of the die, into at three-dimensional section with transverse sectional parts. According to the invention, the rotary die has a varying pitch radius as measured from the axis (C), which allows pressing of sections with varying cross section.

Abstract: The invention concerns a device and a method for continuous pressing of a plastically deformable blank into a three-dimensional section with a predetermined cross-sectional area, comprising a substantially cylindrical, fixed die, an opening formed in the die, through which the plastic blank is intended to be pressed, and at least one rotary die arranged adjacent to the opening, the rotary die having one or more recesses in its peripheral surface for forming the blank, during the rotation of the die, into a three-dimensional section with transverse sectional parts. According to the invention, the rotary die is arranged immediately downstream of the opening, whereby the blank is reducible, when passing through the opening, substantially down to the predetermined cross-sectional area, and formable, when passing the rotary die, thereby determining the final shape of the three-dimensional section.

Abstract: There is disclosed an aluminum or aluminum alloy extruding die, which comprises Co-group alloy, Ni-group alloy, Cr-group alloy or like high temperature wear-resistant alloy coating applied by thermal spraying on a required die surface portion having been formed in the shape of a rough surface having surface roughness Rz of 5 &mgr;m or more. Preferably, after application of the alloy coating, the die is held at a temperature in the range from 500 to 800° C. for a predetermined period of time or the alloy coating surface is so roughened as to have surface roughness Rz of 10 &mgr;m or less.

Abstract: A split die includes a plurality of die pieces which can be assembled into a die nib. The die nib defines a central wire forming passage which has a cross section of a substantially rectangular shape or a square. The cross section of the wire forming passage is progressively smaller such that the wire forming passage has a predetermined approach angle. Each of the die pieces has a passage segment of a generally triangular shape to partially define the wire forming passage. The die piece has a pair of side lines each passing a point on an axial center line of the wire forming passage.

Abstract: An extrusion die set includes a charging die and forming die that permit the extrusion of seamless hollow products from a solid billet of aluminum or aluminum alloy on a single cylinder horizontal extrusion press. The charging die imparts a rotational component to the portions of a divided extrusion charge. The portions are combined in a zone of high pressure and further blended in a mixing space having a continuously variable configuration in the extrusion direction. The portions of the extrusion charge are so thoroughly blended that the hollow products have an uninterrupted molecular and crystalline configuration.

Abstract: A method of determining at least one dimension of an extrusion die includes determining a plurality of reference points on a contour of an opening of the extrusion die. Sizes of a plurality of figures with same shapes corresponding to the plurality of reference points are determined. Each of the plurality of figures is inscribed in the contour of the opening and has at least one axis of symmetry. Each of the plurality of figures contacts each of the plurality of reference points and at least one another point on the contour. The at least one dimension of the extrusion die is determined based on the sizes of the plurality of figures.

Abstract: There is disclosed an aluminum or aluminum alloy extruding die, which comprises Co-group alloy, Ni-group alloy, Cr-group alloy or like high temperature wear-resistant alloy coating applied by thermal spraying on a required die surface portion having been formed in the shape of a rough surface having surface roughness Rz of 5 &mgr;m or more. Preferably, after application of the alloy coating, the die is held at a temperature in the range from 500 to 800° C. for a predetermined period of time or the alloy coating surface is so roughened as to have surface roughness Rz of 10 &mgr;m or less.

Abstract: In an improved process for drawing metal wires and a tool for actuating the process, a metal wire is coated with a thin surface layer of lubricant and subsequently drawn, gradually in a series of single drawing operations. In a final of the drawing operations, the wire is forced to pass through a hole which exhibits an angle of convergence comprised between 30 degrees and about 85 degrees. As the wire passes through the hole, the layer of lubricant is removed and the drawn wire exiting from the hole is clean and lubricant-free.

Abstract: A tool suited to the pressure wire drawing of wire rods and wires having a hole passing through it, includes a casing detachably disposed within the casing, a wire drawing nib separate from the pressure die and detachably disposed within the casing and aligned with the above mentioned hole, and at least one gasket between the wire drawing nib and the pressure die designed to make the passage formed between the pressure die and wire drawing nib leak-proof.

Abstract: In an extrusion tool—in particular a disk-shaped pressing die with at least one shaping opening for the extrusion of metal such as aluminum or an aluminum alloy—comprising a steel material—in particular a low-distortion hot-working steel—with a surface coating, the coating on the extrusion tool is made from coating material which is selected from the group containing carbides, nitrides, oxides and combinations of those substances, wherein the coating material is applied to the extrusion tool by a CVD-process.

Abstract: A die for reducing the formation of flash on parts includes a first die section and a second die section defining therein a cavity. The first die section includes a pair of first surfaces and the second die section includes a pair of second surfaces which together define a pair of parting lines which extend from opposite sides of the cavity. Desirably, the first die section includes a pair of lands, each extending along the length of one of the parting lines. Each land defines a first surface portion of the first surface and is sized and configured so that the land is elastically loaded, e.g., substantially equal to and less than the elastic limit of the material forming land when forming a part.

Abstract: An extrusion die is provided to improve wear resistance and to suppress damage to the shaping section of the core die. The core die consists of a plurality of individually prepared protruding rod members 5 that includes a protrusion section 3a and a base section 3b that extends in the upstream direction with respect to the metal flow. The protruding rod members 5 are arranged in parallel in locating grooves 12 fabricated on the male die assembly 2. Each protruding rod member 5 has a base section 3b and a transverse locking notch 7 so that a stopper 8 locks all the protruding rod members 5 to prevent them from shifting in the axial direction of the protruding rod member.

Abstract: The present invention is addressed to improving a blank for a wire drawing die formed from an annular cemented metal carbide support component having a lengthwise extent from an entrance end to an exit end and extending radially about a central longitudinal axis to define a cylindrical internal bore through the lengthwise extent, and a cylindrical sintered polycrystalline compact component received within the bore of the support component and bonded thereto at an interface surface extending a radial distance from and along the longitudinal axis from a wire drawing entrance end to a wire drawing exit end. The compact component is adapted to receive an aperture extending through its lengthwise extent about the central longitudinal axis and is configured with an entrance zone at the die entrance end which tapers inwardly therefrom to a reduction zone whereat a wire to be drawn through the aperture makes initial contact with the compact component, and thence to a bearing zone and an exit zone.

Abstract: An easy mode pipe-diameter reducing device provided for feeding a metallic pipe into the hole confined by the wall surfaces of a conical spring mounted in the die bodies of the device, wherein, wall sections of the die bodies with constant diameter guides the metallic. pipe, and wall sections of the die bodies with tapering shapes contract the wall of the metallic pipe. Thereby, the peripheral pipe wall is gradually contracted under confining of the tapering wall surfaces of the die bodies. Wherein, the pipe-diameter reducing device is comprised of an upper die body and a lower die body having a conical spring provided therebetween, the inner diameter of the conical spring forms the wall surfaces extending from the wall sections with constant diameter to the tapered wall sections thereof. Therefore, when the metallic pipe is fed till it contacts the tapered wall sections, it can be contracted thereby into the shape of a tapered pipe. Hence easiness of pipe reducing can be achieved.

Abstract: In an extrusion tool—in particular a disk-shaped pressing die with at least one shaping opening for the extrusion of metal such as aluminum or an aluminum alloy—comprising a steel material—in particular a low-distortion hot-working steel—with a surface coating, the coating on the extrusion tool is made from coating material which is selected from the group containing carbides, nitrides, oxides and combinations of those substances, wherein the coating material is applied to the extrusion tool by a CVD-process.

Abstract: A production method and its corresponding mold for manufacturing aluminum alloy heat sinks with extra high profile ratios. The mold comprises a feed section and a form section. The form section is made from a high strength mold steel and contains a plurality of fin forms. The form section includes one or more crossbeams supporting the fin forms. The feed section is generally coaxial with the form section. The mold allows the extrusion of aluminum alloy heat sinks with extra high profile ratios which are difficult to produce by other methods.

Abstract: A steel billet is reduced to a bar in a hot steel mill rolling operation by plural reductions successively produced by passage of a workpiece through a series of reducing mill stands. Each mill stand produces a workpiece having a rhombic shaped cross sectional configuration during a reduction passage through each mill stand. The plastic deformation of the workpiece produced by the rollers in each mill stand not only reduces the cross sectional area of the workpiece but also reverses the major and minor axes of the rhombic cross section of the workpiece during passage through each mill stand.

Abstract: A collar hole die for forming a hole in brass headers used in radiators with a collar around the periphery of the hole. The collar hole die includes a body with top and bottom faces, and an outer side. The body has a center bore extending therethrough between the top and bottom faces of the body. The top face of the body has an annular extent upwardly extending therefrom around the outer periphery of the center bore. The annular extent has an upper, inner and outer portions. The inner portion of the annular extent has an annular inner recess therearound adjacent the upper portion of the annular extent.

Abstract: An extrusion die (11) comprises a die cavity (12) having a shape corresponding to the cross-sectional shape of the required extrusion, and a preform chamber (19) in communication with the die cavity (12), the preform chamber (19) being of generally similar shape to the die cavity (12) but of greater cross-sectional area, so that regions of the preform chamber (19) communicate with corresponding regions respectively of the die cavity (12). Each region of the preform chamber (19) has a bearing length (20) which is so determined in relation to its dimensions and position that, in use, extrusion material passing through each region of the preform chamber (19) is constrained to move at a velocity such that the material passes through all regions of the die cavity (12) at a substantially uniform velocity.

Abstract: The inventive pressure die holder is comprised of an elongate hollow steel cylinder which receives a series of dies in an interior cavity. The dies are maintained within the cavity by means of a cap which is attached to one end of the pressure die holder. The inventive pressure die holder is provided with two sets of vents which relieve lubricant pressure within the pressure die holder. The first set of vents are located in mid portion of the body of the pressure die holder in alignment with the dies. The first set of vents reduce pressure between the die pair, allowing the lubricant to flow through the die at a cooler temperature. The second set of vents are located in the body of the pressure die holder adjacent the cap, and allow the cap to be removed from the pressure die holder at the end of the drawing operation.

Abstract: A method and apparatus has been developed for the work hardening of tungsten alloy rods while achieving a high degree of diametrical control. The method employs multiple extrusions through extrusion dies designed to prevent cracking and delamination of the rods.

Abstract: An extrusion die (10) includes a die body (30) having an upstream face (32) and a downstream face (34) with an extrusion profile (22) passing through the body (30) from the upstream face (32) to the downstream face (34). The walls of the extrusion profile (22) being the bearing (46) of the die (10). A pocket (40) having tapered sidewalls (70) is formed in the upstream face (32) of the die (10) and surrounds the extrusion profile (22). The configuration of the pocket (40) improves the material flow through the die (10). The configuration of the pocket (40) depends on the configuration of the extrusion profile (22). The width of the pocket (40) is small at the fast areas of the extrusion profile (22) while being large at the slow areas of the extrusion profile (22). The pocket (40) alters the entry angle of material as it enters the die (10) thus reducing friction in the die (10) and allowing increased extrusion speeds.

Abstract: When used, a hot extrusion forging die for use in titanium alloy according to the present invention extrusion works a heated titanium alloy-made billet in such a manner as to diameter-reduce the billet. The hot extrusion forging die for use in titanium alloy according to the present invention is equipped with a die member for extrusion working. The die member is made of ceramic. The forging die according to the present invention makes it possible to suppress the sticking of the die member onto an extruded work to thereby make it easy to take out the extruded work. Also, the forging die according to the present invention makes it possible to suppress the seizure of the titanium alloy-made billet, with the result that there can be used a lubricant for which the removing operation is not needed to be done.

Abstract: The present invention is addressed to improving a blank for a wire drawing die formed from an annular cemented metal carbide support component having a lengthwise extent from an entrance end to an exit end and extending radially about a central longitudinal axis to define a cylindrical internal bore through the lengthwise extent, and a cylindrical sintered polycrystalline compact component received within the bore of the support component and bonded thereto at an interface surface extending a radial distance from and along the longitudinal axis from a wire drawing entrance end to a wire drawing exit end. The compact component is adapted to receive an aperture extending through its lengthwise extent about the central longitudinal axis and is configured with an entrance zone at the die entrance end which tapers inwardly therefrom to a reduction zone whereat a wire to be drawn through the aperture makes initial contact with the compact component, and thence to a bearing zone and an exit zone.

Abstract: A tool suited to the pressure wire drawing of wire rods and wires having a hole passing through it, includes a casing detachably disposed within the casing, a wire drawing nib separate from the pressure die and detachably disposed within the casing and aligned with the above mentioned hole, and at least one gasket between the wire drawing nib and the pressure die designed to make the passage formed between the pressure die and wire drawing nib leak-proof.

Abstract: An extrusion die for use in producing aluminum alloy articles of extruded shapes or tube having a void with defined internal dimension, said die comprising:i) a die plate with at least one die cavity defined by a first die bearing surface which defines an external shape for such extruded article;ii) an extruding mandrel secured in said die cavity and having a second die bearing surface which defines an internal shape for such extruded void;iii) a truing mandrel positioned beyond said mandrel second die bearing surface for correcting internal shape of such void and providing such defined internal dimension, said truing mandrel having a forming surface defining an external dimension relative to an external dimension of said extruding mandrel for correcting of internal shape where said truing mandrel external dimension is at least equal to a lower limit for finish tolerance on such internal dimension, said truing mandrel forming surface being spaced from said extruding mandrel bearing surface by a reduced portio

Abstract: A die for extruding solid aluminum profiles having variable thickness is defined with outlets and a bearing length which is constant throughout the profile. The flow of metal into the profile is defined by calculating an angle of entry of the metal at each point of the profile. The angle is a function of a ratio of a perimeter to the thickness of the profile at each point thereof. A feed chamber has at least one step with an interior edge. The interior edge defines the angle relative to the orientation of the profile.

Abstract: A die (104) for forming a blank (14) into a container body (26) having an open end provides an annular undulated shaping surface (106) of substantially uniform radius. The container body (26) is formed by moving the blank through the shaping die (104), with the result that the undulations (106) laterally redistribute metal in the sidewall of the container body, as well as iron the sidewall during the forming process. The die enables the use of a blank (14) of noncircular geometric shape, such as a hexagon, by redistributing metal from the points of the hexagon to the area of the flats in order to produce an end product without excessive earing.

Abstract: A method for making hollow workpieces such as beverage containers with a circular die in which an aluminum alloy is strip cast whereby the alloy is solidified rapidly without substantial precipitation. Thereafter, the aluminum alloy is formed into a cup which is drawn and passed through one or more dies to iron the walls of the cup and thereby lengthen the side walls thereof using at least one circular die having a die angle of less than about 6 degrees and a chamfer angle of less than 35 degrees. It has been found that the use of such die angles prevents or minimizes galling and tearoffs.

Abstract: A hollow extruding die for extruding a hollow section of a zinc-containing aluminum alloy is provided. The die is protected from cracks and has an extended life, without requiring any substantial structural changes to the die. In the die mandrel of the die a mandrel is connected by bridges with an outer cylindrical member. The bridges have a tapered projection facing toward the mandrel. A 3 mm thick coating composed of a nickel alloy is bonded on the surface of the projection by padding the welding material. Instead of coating the bridges, a covering can be attached to the surface of the bridges. To receive the covering, an engaging groove extends from the root of the mandrel and along the surface of the bridges to the outer cylindrical member of the die mandrel. The covering is composed of the same steel material as that of the die or of the nickel alloy. The covering has a through hole for receiving the mandrel formed on the base.

Abstract: A wire drawing die having improved physical properties, and a blank therefor. A cemented metal carbide support component having a lengthwise extent is provided to extend radially about a central longitudinal axis to define an internal bore therethrough. For receiving the wire to be drawn through an internal thereof, a sintered polycrystalline compact component is received within the bore of the support component. The compact component is bonded to the support component at an interface surface extending along the longitudinal axis from a first end spaced a first local maximum radial distance from the axis to a second end spaced a second local maximum radial distance from the axis. The interface surface is radially symmetrical about the longitudinal axis and extends radially inwardly from the first and the second end to define an intermediate region therebetween spaced a local minimum radial distance from the axis.

Abstract: A composite diamond wire die for drawing wire has a single crystal or HTHP diamond substrate and a CVD layer or layers deposited thereon. A wire die bore extends through the substrate and between the CVD layers, with a wire bearing surface being located completely within the substrate. The CVD layers may be deposited so as to develop tensile stress therein, so as to place the substrate in compression.

Abstract: A composite diamond wire die for drawing wire has a single crystal or HTHP diamond substrate and a CVD layer or layers deposited thereon. The wire die bore extends through both the substrate and the CVD layers, with the wire bearing surface being located within the substrate.

Abstract: A composite diamond wire die for drawing wire has a single crystal or HTHP diamond substrate and a CVD layer or layers deposited thereon. The wire die bore extends through the diamond substrate, and the substrate is surrounded by the diamond CVD layer.

Abstract: A container body is produced from a blank, by first forming the blank from sheet stock in hexagonal shape, thereby eliminating scrap from the blanking process. A die ring is configured to laterally redistribute material from the point areas of the hexagon into intermediate areas during the draw-and-iron can forming process, usefully incorporating this material instead of trimming it.

Abstract: A deforming tool having a die and prestress ring for the extrusion of a workpiece. The prestress ring being constructed so that the radial prestress exerted by it on the die in a region of transition from one to the other of two converging inner faces of the die, which together form an internal angle of less than 180 degrees, and/or in the region of a sudden transition from a low to a high value of the pressure exerted by the workpiece during its deformation radially on the die, is less than in the regions adjacent to the transition.

Abstract: An extrusion die (10) includes a die body (30) having an upstream face (32) and a downstream face (34) with an extrusion profile (22) passing through the body (30) from the upstream face (32) to the downstream face (34). The walls of the extrusion profile (22) being the bearing (46) of the die (10). A pocket (40) having tapered sidewalls (70) is formed in the upstream face (32) of the die (10) and surrounds the extrusion profile (22). The configuration of the pocket (40) improves the material flow through the die (10). The configuration of the pocket (40) depends on the configuration of the extrusion profile (22). The width of the pocket (40) is small at the fast areas of the extrusion profile (22) while being large at the slow areas of the extrusion profile (22). The pocket (40) alters the entry angle of material as it enters the die (10) thus reducing friction in the die (10) and allowing increased extrusion speeds.