Abstract: A method for manufacturing an article (420) having a peripheral portion (422) may include reverse squeezing an initial peripheral portion (22) of an initial article (20) to form a first intermediate article (12) having a first intermediate peripheral portion (122) that is partly thinned, and squeezing the first intermediate peripheral portion (122) of the first intermediate article (120) to form a second intermediate article (220) having a second intermediate peripheral portion (222) that is thickened throughout.

Abstract: The present invention relates to a method for fabricating a roller follower assembly, comprising the steps of fabricating a lash adjuster body, fabricating a roller follower body, fabricating a leakdown plunger, fabricating a socket, wherein at least one of the lash adjuster body, roller follower body, leakdown plunger, and socket is fabricated at least in part by forging.

Abstract: A hot forge forming facility includes at least a material supply device, a heating device, a guiding device and a punching device. The material supply device carries a continuous supply of metal material in rolls. The heating device heats and softens the metal material. The guiding device guides and drives the metal material to the heating device. The punching device compresses, forms and cuts the softened metal material in continuous punching operation to smoothly and quickly produce desired products that are consistent with actual production requirements.

Abstract: A closed forging method for producing a forged product includes preparing as a forging material a cylindrical cast ingot that has a volume the same as the volume of a forged product and assumes a shape having an upper surface, a lower surface and a side surface and containing no angular portion; and applying pressure to the side surface of the forging material. The shape has a ratio of the lateral length of a projection profile of the forging material as viewed in the direction perpendicular to the direction of pressure application to a length of the forging material as measured in the direction of pressure application is 1 or less. The forged product obtained is a preform of an upper arm or a lower arm with a plurality of branches that is a suspension part for a vehicle or a yoke with a plurality of branches that is a joint part employed in a vehicle suspension. The preform or yoke has metal flow lines along each branch and exhibits enhanced mechanical strength.

Abstract: A novel method of making a nozzle by forcing a malleable metallic disk into a series of cavities in progression using punches to draw down a formed section so metal can be pulled into the shape of the next cavity in the series. Each cavity differs in size and shape, progression of the nozzle to the next cavity occurs until the metal is incrementally hardened by each step in the progression and the desired shape is formed. Wall thickness of the nozzle can be selectively varied in each section drawn down or pulled. Exceptionally accurate nozzles can be made with smooth, hard, rigid, walls of varying and constant thickness at low cost.

Abstract: A method for forging a rack bar from a blank pipe. Prior to the rack forging process, a blank pipe is subjected to a process for obtaining an adjustment of a cross-sectional shape of the blank pipe. Such a preliminary adjustment is constructed by a swaging process for reducing an outer diameter of the blank pipe and a ironing process for obtaining a desired irregular cross-sectional shape of the blank pipe. The ironing process is such that locally thickened wall portions are obtained at length wise ends as well as tooth width ends of a rack forging die.

Abstract: A method comprises steps of providing bar stock, cutting the stock to form a rod-shaped blank, and stamp-forming a ball section on a first end of the blank in a transfer die. The method further includes stamp-forming an apertured flattened section on a second end of the blank to form a final product in the transfer die, and axially striking opposing ends to accurately form a length of the blank. A related transfer die apparatus includes stations for cutting and then stamp-forming a ball section on a first end of the blank, and stamp-forming an apertured flattened section on a second end of the blank to form a final product.

Abstract: A method for manufacturing a surgical needle devoid of a grinding process includes the steps of swaging a needle blank to define a substantially tapered or conical needle end, pressing the tapered needle to form a plurality of intersecting surfaces and forming cutting edges along the lines of intersection of the intersecting sides. The needle may be subjected to an etching process (e.g., an acid bath) to sharpen the cutting edges and/or provide a matte finish on the needle. The needle produced by the novel process is extremely sharp and durable, and exhibits an enhanced retention of sharpness relative to conventional ground needles over periods of prolonged use.

Abstract: A method for manufacturing a crank arm and spider assembly includes the following steps: (1) providing a blank; (2) shaping the blank to form a crank billet comprising an elongate body having a first end on which a spider is integrally formed and an opposite end having an expanded outside diameter; (3) forming a channel substantially co-extensive with the elongate body with an opening at the second end of the body; (4) reducing the expanded second end and thereby reducing inside diameter of the channel in proximity of the second for forming an entry of the channel; (5) filling a liquid into the channel through the entry and then sealing the entry; (6) placing the crank billet with the liquid filled in the channel into a mold and performing a mold forging operation to obtain a semi-product; and (7) forming a hole in the body to release the filling liquid out of the channel of the crank.

Abstract: A method of making a metallic shell for a spark plug. The metallic shell includes a multi-stepped through hole, an intermediate tubular portion, a tip end side tubular portion and a base end side tubular portion. The through hole includes a large diameter hole section, an intermediate diameter hole section and a small diameter hole section. The method includes the steps of cutting a metal pipe that is used as a starting material to a predetermined length and thereby preparing a pipe-shaped blank, and subjecting the blank to a deformation process and thereby forming the blank into the metallic shell. A spark plug and a method of making the same are also disclosed.

Abstract: Method and apparatus for producing a thin walled tubular product with thickened flange. A first stage metalworking (drawing) of a circular plate material A is done by using a first die set 22 having a conical die 24 and a drawing punch 26 is done in a manner that the end of the blank plate is remained on the conical surface 24-1 of the die, so that a semi-finished tubular product A1 with a inclined flange A1-1 is obtained. Then, a second stage metalworking (drawing) of the semi-finished tubular product A1 is done by a second die set 32 having a shaping punch 34 and a restraint die 36. The semi-finished tubular product A1 is held by the restraint die 36 and the shaping punch 34 is introduced into the semi-finished tubular product A1 for effecting a wall thickness reduction under ironing principle while forming a stepped portion.

Abstract: A metal container with thread capable of preventing such a defect that the strength of a lower end of a mouth part and an upper end of a shoulder part of a container main body is non-resistant to a pressing force in radial and axial directions, and a part of the container may be collapsed or buckled during a capping operation where content is filled into the container and cap is fitted to the container automatically by a machine, characterized in that at least one or more inwardly curving smooth annular recessed parts (4) and at least one or more outwardly curving smooth annular projected parts (5) are formed in an area ranging from the lower end (2a) of the mouth part (2) of the container main body to around the upper end (3a) of a tapered shoulder part increasing gradually in radial direction.

Abstract: A method of manufacturing a steering rack bar (6) by forging, the method comprising the steps of pacing a heated cylindrical rack bar (6) in a first forging die (15) and forging a first toothed protion (37) at one end thereof; removing the rack bar; heating the rack bar at or near the other end of said rack; and placing the other end of the rack bar in a second forging die and forging a second toothed portion (39) wherein, prior to forging the second toothed portion, the rack bar is axially and angularly aligned to a predetermined axial location and angularly orientated utilising the first toothed portion or features at or near the one end of the rack bar as a datum, and placed and held in the predetermined axial location and angular orientation prior to forging of the second toothed portion.

Abstract: A method of creating a cobalt chronic femoral knee component includes the steps of: providing a forging press including first and second bust forging die parts spaced apart from each other and movable toward each other, the first and second bust forging die parts including respective femoral knee component shaped cavities; placing a cobalt chrome ingot heated to a temperature of between about 2050° F. and about 2300° F. between the first and second bust forging die parts in alignment with the femoral knee component shaped cavities; and bringing the first and second bust forging dies parts together in a bust blow against the cobalt chronic ingot under a pressure between about 1500 tons and 2000 tons creating a femoral knee bust forging.

Abstract: Aerosol cans, more particularly, aluminum aerosol cans made from disks of aluminum coil feedstock, are provided. A method for necking aerosol cans of a series 3000 aluminum alloy is also provided. The method prevents the cans from sticking in the necking dies and produces a can with a uniquely shaped profile. The aluminum aerosol cans that are produced have the attributes of strength and quality, while being produced at a cost that is competitive with steel aerosol cans.

Abstract: A metallic plate member is provided. A first punch is operable to perform a first forging work to mold a first member in the plate member. The first member has a first function. A second punch is operable to perform a second forging work to mold a second member in the plate member. The second member including at least one kind of positioning member. The first forging work and the second forging work are performed at a single stage.

Abstract: A method of making a part with regions of different thickness from a plate workpiece having a pair of substantially parallel plate faces. The workpiece is fitted between a surface of a die and a substantially parallel surface of a punch. The die is formed at its surface with an opening. Then the die and the punch are relatively shifted parallel to the surfaces and faces and so as to compress the workpiece parallel to its faces to extrude the workpiece transversely into the opening in the die surface, thereby creating a region of greater thickness.

Abstract: A method for forging/molding a coarse blank of an oil cylinder, including steps of: placing burn-in softened aluminum material into a preheated mold; using a first punch head to first forge the aluminum material in the mold cavity from outer side of the molding hole so as to form a blank body of the oil cylinder with a first end cap, a second end cap and a shorter cylinder body; moving out the first punch head and connecting an extension mold with the mold; and immediately using a second punch head to secondarily forge the blank body in the mold cavity from outer side of the extension hole and making the end section of the second punch head extend into the mold cavity to a position near the inner end of the mold cavity, whereby the cylinder body of the blank body outward axially extends to the extension mold into a predetermined length so as to form the oil cylinder.

Abstract: A die for forming a work-piece having a complex geometry includes a die insert having an interior surface that defines a first portion of the complex geometry and a retainer ring that selectively engages the die insert. The retainer ring includes a circumferential interior surface that defines a second portion of the complex geometry. A punch insert that is slidably disposed in the retainer ring and includes a surface that defines a third portion of the complex geometry.

Abstract: A forging machine includes a machine bed, a driving unit driven by a driving source to activate a feeding unit, a sliding seat unit, and a forging unit. The machine bed includes left and right sidewalls. The driving unit is disposed at an inner side of the left sidewall. The sliding seat unit is disposed at an outer side of the right sidewalls, and includes a sliding plate unit that can reciprocate forwardly and rearwardly to activate a cutting unit and a holding unit. The sliding plate unit is guided by a guiding roller mechanism such that the sliding plate unit moves smoothly.

Abstract: A clutch housing assembly for use in vehicle drivelines includes at least one strengthening member at an open end of the housing. The strengthening member preferably is formed by cutting away portions of the housing near the open end and then deforming the remaining portions. The deformed portions preferably are folded over and against a surface of the housing near the open end. The strengthening members provide additional strength to the housing at the open end to resist deformations that may otherwise occur because of forces incident on the assembly during operation of the vehicle driveline.

Abstract: The method of manufacturing a heat exchanging fin having an oval collared through-hole is capable of reducing manufacturing cost. The method comprises the steps of: forming a circular projected section, whose transverse sectional shape is a circular shape, in a thin metal plate; drawing the circular projected section a plurality of times so as to form into an oval projected section, whose transverse sectional shape is an oval shape and which has a prescribed height, a prescribed major axis and a prescribed minor axis; and boring a through-hole in the oval projected section so as to form the collared through-hole.

Abstract: In a method of forming a protruded shaft on a metal base for an electronic memory device, the metal base is pressed down with a pressing tool from upper face side of the metal base placed on a die. The die is provided with a hole having a predetermined inner diameter and the wall material of the metal base is moved into the hole of the die to form a protruded shaft having a hollow part inside and the tip end closed.

Abstract: A method for increasing structural strength of spokes of a bicycle or a motorcycle, which adopts a mechanically processing measure to increase the structural strength of the bending section of the spoke. The spoke is many times compressed to process and harden the bending section of the spoke so as to enhance the metal strength (shearing strength) of the bending section. At the same time, the wire diameter of the spoke (cross-sectional area) is increased due to compression in accordance with the principle that shearing load=shearing strength×cross-sectional area. With least metal material and lower processing cost, the spoke can have highest structural strength.

Abstract: Method and apparatus for producing a thin walled tubular product with thickened flange. A first stage metalworking (drawing) of a circular plate material A is done by using a first die set 22 having a conical die 24 and a drawing punch 26 is done in a manner that the end of the blank plate is remained on the conical surface 24-1 of the die, so that a semi-finished tubular product A1 with a inclined flange A1-1 is obtained. Then, a second stage metalworking (drawing) of the semi-finished tubular product A1 is done by a second die set 32 having a shaping punch 34 and a restraint die 36. The semi-finished tubular product A1 is held by the restraint die 36 and the shaping punch 34 is introduced into the semi-finished tubular product A1 for effecting a wall thickness reduction under ironing principle while forming a stepped portion.

Abstract: A method of forming inner flanges in a bushing comprises steps of (a) extruding a bushing into an extruding die, (b) cutting an initial upward flange in the bushing, (c) shaping the initial upward flange into a final inner flange, and (d) repeating steps (a) to (c) to form additional inner flanges.

Abstract: A method for manufacturing an article (420) having a peripheral portion (422) may include reverse squeezing an initial peripheral portion (22) of an initial article (20) to form a first intermediate article (12) having a first intermediate peripheral portion (122) that is partly thinned, and squeezing the first intermediate peripheral portion (122) of the first intermediate article (120) to form a second intermediate article (220) having a second intermediate peripheral portion (222) that is thickened throughout.

Abstract: A fabrication method of a metal shell to be installed on a park plug is provided which is made up of a small-diameter portion, a large-diameter portion, and a wrapping portion. The wrapping portion is to be wrapped by staking about the spark plug to achieve installation of the metal shell on the spark plug. The method comprises pressing a workpiece with a punch to shape the wrapping portion of the metal shell in a first cold forging process and processing the workpiece to shape the small-diameter portion of the metal shell in a second cold forging process different from the first cold forging process. This produces the metal shell which is less susceptible to cracks when installed on the spark plug and has an increased service life.

Abstract: A cutting process S1 cuts a wire 1 into cut pieces each having a volume approximately equivalent to that of a desired shoe 11. A forging process S2 sequentially forges cut pieces 2 with forging dies 13, 23, and 33 having three cavities 13c, 23d, and 33e respectively, and obtains a steel sphere 8. A finishing process S3 obtains a shoe-shaped material 10 from the steel sphere 8 without a heat treatment, and carries out a heat treatment to the obtained material 10, thereby to obtain a shoe 11 for a compressor.

Abstract: A method of manufacturing a steel ball for a rolling bearing, said method comprising: a molding step of forming a steel wire cut at a predetermined length into a raw ball having a band portion by a pair of molding forms having respectively hemispherical concave portions and relief grooves in peripheries of said concave portions on their respective opposing faces, said band portion being formed on a surface of said raw ball along said relief grooves by compressing said steel wire by said molding forms in a state in which both ends of said steel wire are sandwiched between said concave portions; and a tumbler working step of removing said band portion from the surface of the raw ball by tumbling.

Abstract: A presently-preferred process for manufacturing a connecting rod comprises placing a heated preform suitable for being formed into the connecting rod into a closed forge die, and forging the preform in a first forging operation while the preform is at a forging temperature to form an as-forged connecting rod having vertical flash extending therefrom. The presently-preferred process further comprises placing the as-forged connecting rod in a second forge die while the as-forged connecting rod is at a temperature substantially equal to the forging temperature, and forging the vertical flash in a second forging operation. The presently-preferred process also comprises removing the as-forged connecting rod from the second forge die, and machining the as-forged connecting rod to predetermined dimensions.

Abstract: In a method of making an axle element for a motor vehicle, a rod-shaped semi-finished product of aluminum is use used as starting material and heated to a desired shaping temperature. A first end of the semi-finished product is upset in a cavity of a shaping die by means of a first punch. Subsequently, the other end of the semi-finished product is compressed in the cavity by a second punch, whereby compressed material is forced into a branch of the cavity to form a pre-forge part with a leg portion. The pre-forge part is then forged into a finished axle element, e.g. a swivel bearing.

Abstract: A process is provided for manufacturing a ball-and-socket joint housing by cold forming from a blank (R), which is preferably produced from a bar or wire material and is prepared for forming. A first axial depression (1) with a diameter (D1) is first prepared by reverse cup extrusion. A second axial depression (2) with a comparatively larger diameter (D2) is subsequently prepared in the axial depression (1) by reverse cup extrusion. A diameter reduction (D3) also of the first axial depression (1) is formed in some sections by the deformation of the material during the second reverse cup extrusion.

Abstract: Compressor shoe is manufactured by cutting a wire into cut pieces each having a volume approximately equivalent to that of a desired shoe. The cut piece is sequentially forged with forging dies having three cavities. The cut piece is first forged to a cylindrical shape with a small rounded portion, then to a rugby ball shape, and then to a shape corresponding to a shoe shape. A finishing step, including heat treatment, is then carried out to obtain a compressor shoe.

Abstract: A process for making ratchet wheels includes a step of providing a work with a first end and a second end, a step of punching the work by means of a punch so as to define a large recess through the second end, a step of cutting away the first end of the work, a step of defining two annular grooves in a periphery of the work and a step of forming a plurality of teeth on the work. The process may include, before the step of cutting away the first end of the work, a step of punching the work in order to define a small recess with a diameter smaller than that of the large recess, a step of punching the work so as to define an opening with a diameter smaller than that of the small recess wherein the opening extends through the first end of the work. The process may include a step of defining a shallow recess in the second end of the work before the step of defining the large recess.

Abstract: A method for producing a unitary toothed part with a shaft and the resulting products. In the process, a blank is formed. The blank includes a shaft part and a flange part. The flange part having a thicker outer diameter and a thinner inner diameter. The outer diameter is formed into a tubular part by drawing. A plurality of teeth and remnants are formed by extruding the tubular part. At least one spline is formed by extruding the shaft part. Through the steps of forming, drawing, and extruding, a blank is made into a unitary part having teeth and a shaft thus increasing precision, rigidity, durability, and reducing forming costs.

Abstract: A hollow metal tubular blank is provided in the wall with one or more reinforcing ribs which are formed by extrusion of the wall. The reinforcing ribs have an inner ridge and an outer ridge. The reinforcing ribs serve to enhance the structural strength of a retaining slot which is formed in the reinforcing portion of the wall of the blank.

Abstract: A method for making a hollow crank includes a three-direction forging step to forge a piece to have a recess in a first end of the prototype; a step of forming a hollow first end of the prototype by forcing the first end through a cone-shaped passage in a mold; a step of forming the first end of the prototype to have an angle relative to the second end of the prototype; a step of setting the first end of the prototype in a cold-forging mold to set the shape of the prototype.

Abstract: A section of heat treated solid steel rod receives a phosphate solution treatment and is inserted into a blind cavity of a first die member within a cold forging press. A punch is forced axially into the rod section in successive steps to cold-forge a first bore and a tubular first end portion of a coupler body. A second end portion of the coupler body is also cold-forged in successive steps after treatments and is either reduced in diameter to receive external threads or is formed with a second bore. Each of the first and second bores receives an end portion of a concrete reinforcing bar after which the tubular end portion of body is compressed or swaged inwardly to secure the body to the reinforcing bar. The second bore may also be machined with internal threads for receiving the external threads on another coupler.

Abstract: A process is provided for manufacturing a ball-and-socket joint housing by cold forming from a blank (R), which is preferably produced from a bar or wire material and is prepared for forming. A first axial depression (1) with a diameter (D1) is first prepared by reverse cup extrusion. A second axial depression (2) with a comparatively larger diameter (D2) is subsequently prepared in the axial depression (1) by reverse cup extrusion. A diameter reduction (D3) also of the first axial depression (1) is formed in some sections by the deformation of the material during the second reverse cup extrusion.

Abstract: A tool for removing damaged fasteners and a method for making such tool wherein the tool (10) includes a first end (12) and a second end (14) with an outside surface (32) and an inside surface (40) defined between ends (12) and (14). A portion (46) of inside surface (40) is in the shape of an hexagonal frustum (54) that has a major end (58) and that includes spiral splines (25). Splines (25) have constant depth between the major end (58) and the minor end (56) of frustum (54) and the relief angle (£) of splines (25) decreases in the direction from minor end (56) toward major end (58). In the method for making the tool (10), a tubular section (118) is made from a tapered blank (91) by piercing one end of the tapered blank with a pierce punch (132). One end of the tubular section is then driven onto a splined punch (162) to provide splines in one end of the tubular section.

Abstract: The invention relates to a method of manufacturing the outer part of a constant velocity joint, the outer part having in the finished condition a hollow chamber with a cylinder-shaped inner wall, in which there are provided ball raceways (1c) which run obliquely of the cylinder axis and are inclined with respect to one another. First, a wobble press die (4) is axially introduced into a goblet-shaped preliminary workpiece (1a) for the outer part having a conically developing inner and outer wall and pre-formed ball raceways (1c) in the inner wall. The preliminary workpiece (1a) is pressed (drawing process) by means of the wobble press die (4), sitting on the floor of the hollow chamber, through an opening in an outer die (2), so that a drawing process is carried out in which the preliminary workpiece (1a) is so cold formed that the inner wall of the hollow chamber is given a cylindrical shape.

Abstract: A method for producing a press in contact having a press-fitting portion having a U-shaped or V-shaped groove in cross-section to be press-fitted in a cylindrical through-hole of a printed circuit board. A block element having a rectangular cross-section corresponding to the press-fitting portion of the contact is formed at its center with a concaved portion by forging. Both the ends of the forged block element are removed by punching. Thereafter, the remaining U-shaped or V-shaped press-fitting portion in cross-section is further so worked by press working that its outer periphery is formed into arcs which are concentric to the through-hole when the press-fitting portion has been press-fitted and fixed therein.

Abstract: A fabrication method of a metal shell to be installed on a park plug is provided which is made up of a small-diameter portion, a large-diameter portion, and a wrapping portion. The wrapping portion is to be wrapped by staking about the spark plug to achieve installation of the metal shell on the spark plug. The method comprises pressing a workpiece with a punch to shape the wrapping portion of the metal shell in a first cold forging process and processing the workpiece to shape the small-diameter portion of the metal shell in a second cold forging process different from the first cold forging process. This produces the metal shell which is less susceptible to cracks when installed on the spark plug and has an increased service life.

Abstract: A bottle-shaped can manufacturing method for forming a shoulder portion having a slope and a diametrically small cylindrical neck portion integrally by further working a bottom side of a bottomed cylindrical can which is formed thinner at its trunk wall than at its bottom wall by drawing a metallic sheet having a thickness of 0.1 to 0.4 mm and by executing at least one thinning working of a bending/extending working and an ironing working.

Abstract: Compressor shoe is manufactured by cutting a wire into cut pieces each having a volume approximately equivalent to that of a desired shoe. The cut piece is sequentially forged with forging dies having three cavities. The cut piece is first forged to a cylindrical shape with a small rounded portion, then to a rugby ball shape, and then to a shape corresponding to a shoe shape. A finishing step, including heat treatment, is then carried out to obtain a compressor shoe.

Abstract: In a method of producing hollow rack bars from steel tubes for use in steering equipment for automobiles and so on, a part of the length of the steel tube to be processed and its adjacent parts is held in split dies that encircle a whole circumference of the tube except for the dies having a hole coinciding with the part of the tube to be processed. Then, a punch is inserted into the hole in a closed state of the dies for flattening a part of the tube, and then mandrels are pushed into the tube for ironing from the inside to form a rack pattern, when a rack forming die is inserted into the hole and held in contact with the flattened part of the tube.

Abstract: The present invention relates to a pressing method for obtaining hydraulic cylinders and high-pressure filters, using a semifinished product consisting of a cylindrical part having a blind hole at one end and suitably treated by means of a first chemical surface treatment. The method comprises a first step in which positioning of the semifinished product in a die is performed, followed by a first pressing operation using a first punch acting over part of the depth of said blind hole, so as to define a first machined zone, followed by a second step consisting of first sizing of said first machined zone using a second reverse-profile punch, so as to define a second machined zone. A third step of performing a second chemical surface treatment, followed by a fourth step of pressing of said second machined zone using a third punch, so as to obtain a third machined zone with a desired thickness, and a fifth step of sizing of said third machined zone using a fourth punch, so as to define a flat contact zone.

Abstract: In a method of making an axle element for a motor vehicle, a rod-shaped semi-finished product of aluminum is use used as starting material and heated to a desired shaping temperature. A first end of the semi-finished product is upset in a cavity of a shaping die by means of a first punch. Subsequently, the other end of the semi-finished product is compressed in the cavity by a second punch, whereby compressed material is forced into a branch of the cavity to form a pre-forge part with a leg portion. The pre-forge part is then forged into a finished axle element, e.g. a swivel bearing.

Abstract: A forging device and a method therefor that enables improve forging precision of a work and lengthen life of dies of a forging device, by efficiently heating the work chiefly made of aluminum in one heating furnace, wherein the device has: a heating furnace for heating works W while moving the works W along the movement path; an intermediate processing means, disposed in the midst of the movement path in a heating furnace, for intermediately forming works W; an intermediate conveyance means for conveying works W from the heating furnace to the intermediate processing means; and a final processing means for making the intermediate conveyance means convey the intermediately formed works W to the heating furnace, reheating the conveyed the works W, and finally processing to form the works W.