Abstract: An apparatus and method for hydroshearing and hydrotrimming for a hydroforming die includes a cutting insert fixed relative to the hydroforming die. The apparatus and method also includes a disposable insert fixed relative to the hydroforming die. The apparatus and method further includes a plunger movable relative to the hydroforming die to allow fluid within a tubular member to force a wall portion of the tubular member outward against the plunger and be sheared in the hydroforming die to trim the tubular member.

Abstract: A high-pressure system for hydroshaping a hollow workpiece has a lower die and an upper die vertically shiftable above the lower die and forming therewith a cavity shaped to hold the workpiece. An upper actuating element bears downward via a vertically compressible hydraulic operating cylinder on the upper die. A spring-loaded pressure-storing cylinder is connected by a hydraulic line to the operating cylinder and to the workpiece. Downward shifting of the actuating element first closes the dies together, then internally pressurizes the workpiece via the line from the operating cylinder such that the workpiece deforms and shapes itself to the cavity, and then fills the spring-loaded pressure-storing cylinder. Subsequent upward shifting of the actuating element at first allows the pressure-storing cylinder to empty, and then entrains the upper die upward off the workpiece by the actuating element.

Abstract: A device for producing an essentially T-shaped hollow profile or a hollow profile provided with at least one branch. The device may have a multipart mold which is intended for internal high pressure forming, in which a hollow profile having at least one initially dome-like branch can be produced. The device may also have a tool at the branch, this tool being designed for opening the branch at the end face after the forming operation. The tool is designed as a cutting device having a parting slide displaceable essentially transversely to the axis of the branch.

Abstract: A method is provided for hydroforming a ring-shaped tubular structure such as a door opening for a vehicle body. The method includes providing a ring-shaped tubular blank having a hollow sealed interior, capturing the ring shaped tubular blank in a hydroforming die cavity, piercing the ring shaped tubular blank with a hollow punch, and introducing pressurized fluid through the hollow punch into the hollow sealed interior to expand the tubular structure to conform with the shape of the hydroforming die cavity and thereby hydroform the ring-shaped tubular structure.

Abstract: A method and a device for producing a tubular object from thermoplastic material. The device includes a die having a movable die body for altering the cross-sectional surface of the die opening, a plunger for extruding a specific quantity of plastic material through the die, and a withdrawal unit for guiding the tubular plastic object emerging from the die. The movements of the withdrawal unit, plunger and die body are controlled such that movement of the withdrawal unit is carried out according to a freely adjustable velocity profile over the path of the withdrawal unit. Movement of the plunger is carried out according to a freely adjustable velocity profile over the plunger path and movement of the die body is carried out according to a freely adjustable position profile over the path of the withdrawal unit or plunger. In this manner, the wall thickness of the tubular object may be adjusted with high accuracy over its length.

Abstract: Electromagnetic (EMF) trimming, flanging and hemming steps are performed at a single workstation in a combined fixture designed to form a hemmed panel assembly, such as a vehicle closure panel. Two or more formed sheets, outer and inner panels, are positioned together for hemming. The panels are clamped and EMF coils are activated to provide EMF force to retain the panels and trim off excess addendum material from the outer panel. The coils are then activated to bend the trimmed edge upward against a flanging member and form a 90 degree flange. Flanging and trimming members are retracted and a coil member positions EMF hemming coils opposite the flange. The hemming coils are then activated and apply EMF force to bend the flange of the outer panel to a 180 degree angle, overlaying the edge of the inner panel and forming a panel assembly having a hemmed edge. Optionally, if needed, the flanging member is then lowered against the flange to assure flatness of the hem.

Abstract: An in-die hydropiercing device comprises a punch with an annular shearing blade which is operated by a hydraulic cylinder and is received in a ring-shaped die button mounted in one of the dies that form a die cavity for the hydroforming of a part, a center support member that is received in the center of the punch and supports the wall of the part inward of the shearing blade during the hydroforming of the part and also during the piercing of the part with the shearing blade, a slug collector, and a slug retainer that is mounted on the center support member and provides for retention of a slug produced from the piercing operation against the center support member and later releases the slug onto the slug collector for disposal following the opening of the dies and insertion of the slug collector between the open dies and then retraction of the slug collector with the slug for slug disposal.

Abstract: A punch for a hydroforming die includes a body, a neck extending axially from the body, a head extending axially from the neck and having a diameter less than a diameter of the body and a thumbnail slot extending axially and radially into the head to allow fluid within a tubular member to force a wall portion of the tubular member outward into the slot of the punch and be sheared by the punch to produce an opening in the tubular member.

Abstract: This invention relates to a method for molding a bicycle tube and the method comprises the following steps: first, providing a tube and then controlling thickness of the tube by a drawing and extruding process for forming a molding portion. Second, plasticize other portions of the tube into particular diameters and shapes by plasticizing processes. Third, hydroform the molding portion of the tube by a mold and a hydroforming device for forming particular three-dimensional shapes. By applying to the above-mentioned method, the tube could be molded into a three-dimensional, unique and delicate shape.

Abstract: A punch assembly used with a hydroforming die includes a punch cylinder for mounting to the hydroforming die and having a movable rod. The punch assembly also includes a punch for piercing an opening in a tubular member disposed in the hydroforming die. The punch assembly further includes a quick change assembly interconnecting the rod of the punch cylinder and the punch for allowing the punch to be removably attached to the punch cylinder.

Abstract: The invention relates to a forming tool for forming sheet blanks in a diaphragm press of the kind comprising an openable, closed pressure chamber, which is divided in a gas and liquid tight manner by means of a flexible diaphragm. The forming tool is arranged on one side of the diaphragm and a sheet blank to be formed is arranged between the forming tool and the diaphragm. The opposite side of the diaphragm is pressurized by a fluid being supplied at high pressure to cause the flexible diaphragm to deform and, thus, the sheet blank to be pressed against the forming tool. The forming tool comprises an elongate cutting and flanging tool along at least part of its periphery and/or around an intended opening in the sheet blank.

Abstract: A double action punch assembly for a hydroforming die includes a first punch segment having an aperture extending therethrough. The double action punch assembly also includes a movable mounting block disposed in the aperture of the first punch segment. The double action punch assembly further includes a plurality of second punch segments connected to the mounting block. The first punch segment is moved in a first action to pierce a tubular member in a first direction and the second punch segments are moved in a second action to pierce the tubular member in a second direction to produce an opening in the tubular member.

Abstract: A punch assembly for a hydroforming die includes a servo motor, a ball screw connected to the servo motor, and a ball nut disposed about the ball screw for movement along the ball screw. The punch assembly also includes a link mechanism connected to the ball nut and a plunger operatively connected to the link mechanism and movable relative to the hydroforming die to allow fluid within a tubular member to force a wall portion of the tubular member outward against the plunger and be sheared by the hydroforming die to produce an opening in the tubular member.

Abstract: A center support punch assembly for a hydroforming die includes a center support member for fixed attachment to a die. The center support punch assembly also includes a button disposed about and space from the center support member for fixed attachment to the die. The center support punch assembly further includes a plunger movable relative to the center support member to allow fluid within a tubular member to force a wall portion of the tubular member outward against the center support member and be sheared by the button to produce an opening in the tubular member.

Abstract: In a method and a device for creating a hole on the outer circumference of a hollow profile which is circumferentially closed and under an internal high pressure, before hole-punching, a punch which is integrated in the internal high pressure forming mold such that it can be guided butts against the location of the hole to be created. When it leaves its position of abutment, the punch creates a punched slug there alongside the hole. To make it possible for holes to be punched at virtually any desired location in hollow profiles in the internal high-pressure forming mold in a simple way, it is proposed that the hole-punching takes place by the punch being moved in the guiding bore of the forming mold by the internal high pressure acting together with a driving element, the body axis of which lies approximately at 90° in relation to the hole punch axis and which for its part is driven in a rotary manner and/or translatory manner in the axial direction.

Abstract: A hydrotapping power unit is disclosed that is operable to hold a hydrotapping tool in a home position adjacent a part while the latter is being hydroformed in a die cavity, to then advance the tool to pierce a hole in the hydroformed part while the part remains in the die cavity and under pressure and then continue to advance the tool to inwardly extrude the part about the hole, to then further advance while also rotating the tool at a feed rate equal to the thread pitch of the tool to thereby form a thread in the pierced hole, and finally retract while also rotating the tool but in the reverse direction and at the same feed rate to release the tool from the threaded hole.

Abstract: A device for punching work pieces in an internal high-pressure forming tool includes a punching die guided displaceably in a bore of the forming tool. The device also contains a drive with which the punching die is moved back and forth between the in-use position and the non-use position. In order to facilitate, in a simple and space-saving manner, the punching of work pieces in the internal high-pressure forming tool, the drive contains a pressure fluid and a pressure transfer device that can be elastically expanded via the pressure fluid between a base firmly attached to the tool and a punch head of the punching die. The pressure transfer device abuts a partition at least indirectly at the punch head.

Abstract: An apparatus and a method for forming an article and performing a secondary operation on the article in-situ. The apparatus includes a closure and a die having a cavity. A source of pressurized gas forces a portion of a sheet into contact with a forming surface having a predetermined shape. A tool is movably connected to the apparatus and is configured to engage the sheet to perform a secondary operation while the sheet is held in compression between the closure and the die.

Abstract: Method and apparatus are disclosed wherein a required threaded hole is formed in a hydroformed part with a single tool while the part remains in a hydroforming die cavity. In forming the threaded hole, a hole is first pierced in the wall of the part and then an annular region of the part extending about the hole is extruded inwardly to form an integral tubular neck defining a hole of predetermined depth. The hole is then expanded in a sizing operation to a diameter determined by the required thread to be formed therein by material displacement and the required thread is then formed in the wall of the hole in a material displacing manner.

Abstract: A hydrotapping power unit is disclosed that is operable to position and hold a hydrotapping tool in a home position adjacent a part while the part is being hydroformed in a die cavity, to then advance the tool to pierce a hole in the hydroformed part while the part remains in the die cavity and under pressure and then continue to advance the tool to inwardly extrude the part about the hole, to then further advance while also rotating the tool so that the tool is fed at a feed rate equal to the thread pitch of the tool to thereby form a thread in the pierced hole, and finally to retract while also rotating the tool but in the reverse direction and at the same feed rate to release the tool from the threaded hole.

Abstract: A method of forming a structural member includes hydroforming the blank to form a hydroformed member and finishing the hydroformed member by positioning the wall of the hydroformed member between a die surface and an electromagnetic discharging element having a non-circular cross-section, and actuating the electromagnetic discharging element so that the metallic wall of the hydroformed member presses against the die surface.

Abstract: A method of forming a tubular member with at least one flange includes the steps of providing a tubular member, expanding at least one portion of the tubular member, and positioning the tubular member between open die halves. The method includes the steps of applying at least nominal internal hydraulic pressure to the tubular member. The method further includes the steps of progressively closing the die halves to progressively deform the tubular member and progressively expel the at least one portion of the tubular member to define a flange comprised of wall portions of the tubular member engaging one another. The method includes the steps of increasing the hydraulic pressure to expand and conform the tubular member. The method also includes the steps of separating the die halves and removing the tubular member having a flange from the die.

Abstract: A metal plate is formed in a process comprising cutting, perforating or both, by forcing the plate, by means of an abrupt and intense force towards a mold having openings or boundaries defined by wall sections which extend essentially normal to the forming plane of the mold. Consequently, the plate is cut along the edges of the openings or boundaries. The force may be a pulsed magnetic force or may be a force generated as a result of the discharge of electric current through a fluid.

Abstract: The present invention pertains to a transparent conductive layered structure having a transparent substrate and a transparent 2-layer film consisting of a transparent conductive layer and a transparent coating layer formed in succession on this substrate, that is used for instance, in the front panel of displays, such as CRTs, etc. The above-mentioned transparent conductive layer has as its main components noble metal microparticles with a mean particle diameter of 1 to 100 nm composed of gold and/or platinum and silver and containing 5 to 95 wt % gold and/or platinum, colored pigment microparticles with a mean particle diameter of 5 to 200 nm, and binder matrix. The noble metal microparticles are mixed at a ratio of 1 to 40 parts by weight per 1 part by weight colored pigment microparticles. Moreover, it is characterized in that the transparent 2-layer film has a surface resistance of 10 to 5000 &OHgr;/□, reflectance of 0 to 2.

Abstract: A process for manufacturing holes on the circumference of a hollow section situated in an internal high pressure forming tool uses the action of a punch integrated in the forming tool. A desired breaking point is formed on the hollow section, which follows the edge contour of the operating face of the punch; and after the withdrawal of the punch, the hollow section material surrounded by the desired breaking area, acted upon by internal high pressure, is extracted from the hollow section from the inside to the outside, forming a hole. In order to produce holes on the circumference of hollow sections, in which the shape of the outer circumference of the hollow section is maintained, the wall of the hollow section is weakened to form an unstable thin area. The punch penetrates into the wall of the hollow section at an internal high pressure which corresponds to the forming pressure for forming a hollow blank inserted in the forming tool.

Abstract: Hydroforming apparatus includes in-die hydropiercing apparatus with easy and precise adjustment of the positioning of a backup plunger that is received in a die button and is positioned in a hydroforming position, a prepiercing position, a piercing position, and a slug ejecting position that may be outside the plunger or may be the hydroforming position. Wherein the plunger is required to be precisely positioned and held in the prepiercing position in the die button in order to obtain a desired prepiercing action without prematurely piercing the hydroformed part. The in-die hydropiercing apparatus has a plunger actuating hydraulic cylinder that moves the plunger to the different positions and a cam actuating hydraulic cylinder that positions a cam in determining the prepiercing position of the plunger.

Abstract: A hydroforming assembly has a plurality of die structures that are mounted on a press for reciprocating movement between open and closed conditions. The die structures have cooperating die surfaces defining a die cavity when in the closed condition and receive a metallic tube blank when in the open conditions. A hydroforming fluid supply system has tube-end engaging structures that are movable to selectively and sealingly engage opposite ends of the tube blank. The hydroforming fluid supply system provides pressurized fluid into an interior of the tube blank in order to expand the tube blank outwardly into conformity with the die cavity. A punch extends within a passage of at least one of the die structures. The punch is movable between retracted and extended positions. A punch driving assembly drives the punch between the retracted and extended positions to punch a hole into the expanded tube blank.

Abstract: A punch for piercing and sealing hydroforming parts has a roll forming surface that produces an internal rolled edge portion in a formed part immediately following the punch piercing the part wherein the rolled edge portion acts to effect a tight high pressure seal between the part and the punch as the punch continues to form a required hole in the part. The roll-forming surface extends either partially or completely about the punch in determining the extent of the rolled edge portion in the part that it produces and is located between an end portion that effects the piercing operation and a larger finishing portion that completes the formation of the required hole.

Abstract: A method of forming a structural member includes hydroforming the blank to form a hydroformed member and finishing the hydroformed member by positioning the wall of the hydroformed member between a die surface and an electromagnetic discharging element having a non-circular cross-section, and actuating the electromagnetic discharging element so that the metallic wall of the hydroformed member presses against the die surface.

Abstract: A hydroforming assembly has a plurality of die structures that are mounted on a press for reciprocating movement between open and closed conditions. The die structures have cooperating die surfaces defining a die cavity when in the closed condition and receive a metallic tube blank when in the open conditions. A hydroforming fluid supply system has tube-end engaging structures that are movable to selectively and sealingly engage opposite ends of the tube blank. The hydroforming fluid supply system provides pressurized fluid into an interior of the tube blank in order to expand the tube blank outwardly into conformity with the die cavity. A punch extends within a passage of at least one of the die structures. The punch is movable between retracted and extended positions. A punch driving assembly drives the punch between the retracted and extended positions to punch a hole into the expanded tube blank.

Abstract: A method for piercing a tube during liquid impact forming or hydroforming to form a hole with minimal deformation in the material surrounding the hole. The method includes the steps of: (1) filling the tube with liquid; (2) stamping the tube thereby increasing the pressure of the liquid within the tube; (3) piercing the tube while the pressure is elevated with a tapered punch whereby the material around the pierced hole is pushed back toward the die wall due to the elevated internal pressure of the tube; and (4) retracting the tapered punch from the tube with the face of the punch catching on the tube wall to pull the material back toward the die wall.

Abstract: An electromagnetic forming apparatus for forming an essentially planar metal plate into a dish having a three-dimensional pattern, is provided. The apparatus comprises a mould having a forming surface with a contour corresponding to said three-dimensional pattern; a forming coil device; and an electric discharge circuitry for discharging a short and intense electric current pulse through the forming coil device to yield a pulsed magnetic forming (PMF) force for deforming said plate.

Abstract: A fluid form that is used to produce deep-drawn articles (cf. 10) on any presses, and includes a ram (2), a hold-down plate (3) and a die (4), which can be filled, preferably, with water, wherein the sheet metal (10) to be deep-drawn is guided transversely between die and hold-down plate, should be improved in such a manner that no additional tools are required to trim the deep-drawn articles (cf. 10) and, optionally, for other operations. Hereby, the configuration of the respective fluid form as combination tool (1) is provided for the deep drawing operation and for further operations, such as trimming, wall profiling, notching, perforating or the like.

Abstract: The invention relates to a process and apparatus and apparatus for manufacturing holes on the circumference of a hollow section situated in an internal high pressure forming tool, by the action of a punch integrated in the forming tool. A desired breaking point is formed on the hollow section, which follows the edge contour of the operating face of the punch; and after the withdrawal of the punch, the hollow section material surrounded by the desired breaking area, acted upon by internal high pressure, is extracted from the hollow section from the inside to the outside, forming a hole.

Abstract: A process for manufacturing holes on the circumference of a hollow section situated in an internal high pressure forming tool uses the action of a punch integrated in the forming tool. A desired breaking point is formed on the hollow section, which follows the edge contour of the operating face of the punch; and after the withdrawal of the punch, the hollow section material surrounded by the desired breaking area, acted upon by internal high pressure, is extracted from the hollow section from the inside to the outside, forming a hole. In order to produce holes on the circumference of hollow sections, in which the shape of the outer circumference of the hollow section is maintained, the wall of the hollw section is weakened to form an unstable thin area. The punch penetrates into the wall of the hollow section at an internal high pressure which corresponds to the forming pressure for forming a hollow blank inserted in the forming tool.

Abstract: In the present invention a tubular blank and an article such as a bushing to be assembled are loaded into a die. The tube is hydroformed using typical methods and, while the blank is still pressurized, a punch pierces a hole in the tube. The punch also has an article loaded onto it and, as the punch advances, the article is pushed into the tube through the pierced hole. The punch continues to advance such that it pierces a hole in the opposite side of the tube. The punch then retracts leaving the bushing in the tube. The article may alternately be inserted by means separate from the punch.

Abstract: A device and method for expansion forming of an article used in conjunction with an isostatic press comprising a pressure cell equipped with an elastomeric membrane. The expansion forming tool has at least one pressure intensifier and at least one molding cavity. A blank is arranged in the molding cavity and an elastomeric forming body is arranged inside the blank. The pressure intensifier is arranged such that it is acted upon by the elastomeric membrane and it exerts pressure on the elastomeric forming body inside the blank inside the molding cavity so that the blank is expanded into an article shaped according to the shape of the molding cavity.

Abstract: A method and a device for producing leadthroughs on hollow profiles acted upon by a high fluidic pressure in an internal high-pressure forming tool. Dome-like secondary shaped elements are formed outwards in a radial direction from this hollow profile by the fluid pressurizing. The secondary shaped elements are then reverse drawn into the interior of the hollow profile by a punch while held at the prevailing internal high pressure, whereupon, to open the leadthrough, a punched slug is cut out of the base of the reverse-drawn secondary shaped element by the punch. To ensure the process reliability when producing the leadthrough even in the case of a hollow-profile material having low formability and to retain the strength of the hollow profile in the transition region to the leadthrough, in each case a secondary shaped element is formed out of the hollow profile at two opposite locations.

Abstract: A method and a device for producing leadthroughs on a hollow profile useing a high fluidic pressure in an internal high-pressure forming tool. Dome-like secondary shaped elements are formed outwards in a radial direction from this hollow profile by the fluidic pressurizing. The secondary shaped elements are then reverse drawn into the interior of the hollow profile by punches at the prevailing internal high pressure. A punched slug is cut out of the base of the reverse-drawn secondary shaped element by the punch. A bent-in margin of the secondary shaped element lying next to the cutout is then straightened by the punch in a displacing movement directed further inwards by being pressed against a hollow-profile wall.

Abstract: For forming a tubular work into a shaped hollow product by using hydroforming process, a method and a device are described. In the method, female and male dies are prepared. The female die has a longitudinally extending cavity which has a polygonal cross section when receiving the male die. The tubular work is placed into the cavity of the female die. The interior of the tubular work is then fed with a hydraulic fluid, and the pressure of the fluid is increased to a given level. The given level is smaller than a critical level that causes a bulging of the tubular work. The male die is then pressed against the tubular work to deform the same while keeping the hydraulic fluid at the given level, thereby forming a shaped hollow product that has a polygonal cross section that conforms to that of the cavity. The pressing work is continued until a circumferential length of the shaped hollow product becomes shorter than that of the tubular work.

Abstract: A die button flush mounted in the cavity surface of a lower one of two hydroforming dies has a backup plunger received therein that forms a part of this surface when the plunger is in a hydroforming position. A slug ejector received in the lower die also forms a part of this surface and with a tubular part enclosed in the cavity formed by the dies, hydroforming fluid under pressure is supplied to the interior of the part and also to separately act on the plunger. The fluid pressure moves and holds the plunger in its hydroforming position while forming the part to the die cavity surface. The fluid pressure on the plunger is then exhausted allowing the fluid pressure in the part to stretch a portion of the part into the die button while also forcing the plunger to a position that limits this stretching to prevent piercing.

Abstract: A method and a device for producing leadthroughs on hollow profiles acted upon by a high fluidic pressure in an internal high-pressure forming tool. Dome-like secondary shaped elements are formed outwards in a radial direction from this hollow profile by the fluid pressurizing. The secondary shaped elements are then reverse drawn into the interior of the hollow profile by a punch while held at the prevailing internal high pressure, whereupon, to open the leadthrough, a punched slug is cut out of the base of the reverse-drawn secondary shaped element by the punch. To ensure the process reliability when producing the leadthrough even in the case of a hollow-profile material having low formability and to retain the strength of the hollow profile in the transition region to the leadthrough, in each case a secondary shaped element is formed out of the hollow profile at two opposite locations.

Abstract: A method and a device for producing leadthroughs on a hollow profile useing a high fluidic pressure in an internal high-pressure forming tool. Dome-like secondary shaped elements are formed outwards in a radial direction from this hollow profile by the fluidic pressurizing. The secondary shaped elements are then reverse drawn into the interior of the hollow profile by punches at the prevailing internal high pressure. A punched slug is cut out of the base of the reverse-drawn secondary shaped element by the punch. A bent-in margin of the secondary shaped element lying next to the cutout is then straightened by the punch in a displacing movement directed further inwards by being pressed against a hollow-profile wall.

Abstract: A high-pressure shaping system has a tool defining a cavity and having a bore extending along an axis and opening into the cavity which is adapted to receive a workpiece which can be internally pressurized to expand and engage against inner surfaces of the cavity. A punch extending along the axis has an axially inwardly directed inner end displaceable between an inner position generally flush with the cavity inner surface and an outer position spaced axially outward of the cavity inner surface. A spring unit braced axially inward against the punch and axially outward against the tool has a spring characteristic with a high force/displacement ratio up to a break point and a low force/displacement ratio after the break point for urging the punch inward into the inner position.

Abstract: A collapsible panel forming a separation structure between a generally closed inner environment and an outer environment, for instance consisting of a motorvehicle stratified window, incorporating within its mass at least one explosive charge to which an igniter/detonator device is operatively associated to produce detonation of the explosive charge so as to shiver the panel in a controlled way substantially within the plane thereof.

Abstract: The invention relates to a method and apparatus for the production of double-walled hollow sections by means of internal high-pressure forming, a first hollow section being inserted into a second hollow section, after which the double-walled hollow section thus formed is subjected to high internal fluid pressure in such a way in an internal high-pressure forming die that the double-walled hollow section is expanded. During this process, an air gap is formed between the first, inner, hollow section and the second, outer, hollow section.

Abstract: A high-pressure shaping system has a tool defining a cavity and having a bore extending along an axis and opening into the cavity which is adapted to receive a workpiece which can be internally pressurized to expand and engage against inner surfaces of the cavity. A punch extending along the axis has an axially inwardly directed inner end displaceable between an inner position generally flush with the cavity inner surface and an outer position spaced axially outward of the cavity inner surface. A spring unit braced axially inward against the punch and axially outward against the tool has a spring characteristic with a high force/displacement ratio up to a break point and a low force/displacement ratio after the break point for urging the punch inward into the inner position.

Abstract: Method and apparatus for forming unobstructed holes in a hydroformed metal part employs a punch having a peripheral side conforming to the desired hole shape and an end face having a central cutting edge with a high point that contacts on closure of a hydroforming die with an unsupported wall section of the part initiating a stress riser therein. During forming of the part, the hydraulic pressure forces the above wall section outward against this high point increasing the magnitude of the stress riser. The punch is advanced while maintaining the hydraulic pressure causing the above high point to fracture this wall section at the stress riser and the above cutting edge to then split and cut this wall section to form oppositely facing cut edges in this section. Simultaneously, oppositely angled cutting edges at opposite ends of the central cutting edge and at the punch end face periphery then cut this wall section in directions away from the oppositely facing cut edges to form oppositely extending slugs.

Abstract: A punch assembly for a high-pressure shaping tool having a seat opening into the tool has a guide sleeve fitted in the seat, centered on an axis, and having a radially outwardly directed outer surface radially confronting an inner surface of the seat. A punch is axially displaceable in the sleeve. A clamping element engaged radially between the inner seat surface and the outer sleeve surface retains the sleeve in the seat. The seat is formed with a radially inwardly open groove and the element is a ring engaged in the seat. A screw can serve for pressing the ring radially against the punch. Alternately the ring is pressed radially against the punch by fluid pressure applied radially outside the ring. The ring is elastomeric and is normally of C-section.

Abstract: Forming a tubular workpiece by applying fluid pressure to the interior of the workpiece and enclosing the pressurized workpiece in a die that has a die cavity. A portion or the whole of the die cavity has its internal periphery smaller than the external periphery of the workpiece. This subjects the workpiece to compressive forming.