Abstract: Heated superplastic material is deformed using gas pressure which forces the material into a die cavity. Improved three dimensional models for deforming superplastic materials are based upon spherical shapes penetrating the die cavity which is approximated by one of two different rectangular box models. The three dimensional and box models produced radius and thickness equations from which an accelerated gas pressure versus time profile and a minimum thickness value are calculated. The gas pressure deforms the superplastic material at the maximum possible strain rate without rupturing thereby reducing the speed at which parts are formed. Die frictional effects and variable flow stress phenomena are included into the pressure versus time profile computation and thickness equations so as to improve the speed and accuracy of the superplastic forming process.

Abstract: An apparatus and method for controlling the superplastic forming process by measuring and controlling the volume displaced by the blank being formed so as to measure total strain or surface area increase of the blank.

Abstract: Pressurized fluid, pressurized in excess of the yield strength of a billet or rod, is communicated to the exterior of a piercing punch during piercing of the billet or rod to produce tubing, the pressurized fluid is provided to the exterior of the piercing punch during piercing to provide forced lubrication between the piercing punch and the billet or rod to reduce friction therebetween; such communication of pressurized fluid is also for causing self-centering of the piercing punch with respect to the billet or rod during piercing to produce tubing of uniform wall thickness.

Abstract: A press of pressure cell type comprises a press stand with two opposing force-absorbing elements between which a space is formed. In this space there is located a plate with a recess in which an elastic diaphragm is arranged. The diaphragm forms, together with the plate, a pressure cell. Elongated side supports for the diaphragm are provided at the sides of the said space. A tray insertable into the space forms, together with the plate and the diaphragm, a closed press space. The pressure cell is connected to a pressure medium source. Each side support is formed with an elongated recess, in which there is arranged an expansible membr of elastic material. Each expansible member forms a side support for a press tool located in the tray.

Abstract: A press comprising a press stand, a pressure cell arranged in the press stand with an elastic diaphragm and a tray-shaped tool-carrying member, insertable into the press, in which a forming tool and a workpiece are located. In the inserted position of the tool-carrying member in the press, a closed working space is formed between the pressure cell and the tool-carrying member. The diaphragm is placed in a recess in a press plate. The seal between the diaphragm and the press plate consists of a U-shaped sealing ring having flanges directed inwards towards the center of the pressure cell.

Abstract: Methods for developing particular models which accurately predict the material, process and design parameters for superplastic forming of metal parts under optimum conditions consistent with the desired properties in the finished part. Generalized control equations are developed which enable designers to develop consistency of the forming parameters for materials from different lots. The invention permits control of superplastic forming in accordance with particular raw material microstructure and the effects of time, temperature, strain and strain rate during superplastic forming on the material microstructure, and establishes the relationship between the microstructure and the properties of the parts being formed. These methods applied to the specific area of superplastic forming of metal sheets exemplify a more generalized method of conducting systematic research to derive the maximum information from a minimum number of experiments involving available data.

Abstract: Precisely curved, lightweight and low-cost reflectors for electromagnetic radiation are fabricated by use of a tool and a process in which a blank is planar stretched by uniformly applied isotropic and radially extending forces followed by deformation of the stretched blank to a precisely curved surface.

Abstract: A method and apparatus for making golf ball molds is disclosed. The molds are made by placing a smooth, hemispherical metal cup on top of a dimpled, hemispherical master mold, which is the upper end of a bullet-shaped mounting post. The post is fixed in an upright position to the lower half of a hydraulic press.Above the post is a vertically movable upper press half with a urethane insert. The insert has a smooth hemispherical recess or cavity that is designed in size and shape to blanket the top surface of the cup when the press halves are pushed together.When the press halves are pushed together, the urethane insert covers the cup and pushes against it with extreme force. The insert serves basically as a hydraulic fluid and transforms the linear forces produced by the hydraulic press into a uniform pressure acting equally in all directions against the cup.Due to the tremendous pressure exerted by the press, the insert forces the metal cup to assume the dimpled shape of the underlying master mold.

Abstract: Disclosed is a method of forming metallic materials exhibiting the phenomenon of superplasticity, particularly high strength aluminum alloys, by the technique of superplastic forming by focing an alloy blank into a die cavity using opposing fluid pressures, the pressure on the die side of the blank initially balancing the pressure on the opposite blank side, the die side pressure being reduced as the other pressure is maintained constant or increased to deform the blank at a combined high pressure whereby precision molding occurs as the blank engages the die intimately and cavitation in the blank is reduced or alleviated.

Abstract: A rupture disc system comprises a rupture disc including a dome portion and a flange portion interconnected by a transition region and a mounting mechanism for mounting the rupture disc by the flange portion thereof in a pressure relieving vent. The rupture disc includes a thickness reducing groove at least partially circumferentially surrounding the dome portion and located in the transition region thereof. Preferably, the rupture disc is of the reverse buckling type and the groove does not completely surround the dome portion so as to define a tab or hinge within that part of the transition region which is ungrooved or not as deeply grooved as a remainder of the transition region. In addition, the slope or radius of curvature may be increased in the region of the tab. The rupture disc also includes an indentation on the dome portion. The indentation is preferably greatest on the dome portion at a location spaced from the transition region and directly between the tab and a crown of the dome portion.

Abstract: A method of removing a formed part from a die, said part produced by clamping a preform between first and second dies, bringing said preform to within an elevated temperature range suitable for superplastic forming of said preform, and applying pressure to said preform to superplastically form at least a portion of said preform into a cavity of said first die, comprising the steps of:drawing a vacuum between at least a portion of said part and said second die such that said part is secured to said second die; andseparating said second die from said first die while said part is within said temperature range and secured to said second die, such that said part is withdrawn from said cavity of said first die.

Abstract: In a mold for the superplastic forming of a piece from a blank, the distortion of the blank is measured by a hollow tube located within the mold and having one end positioned in contact with the blank. The hollow tube extends through a sleeve fixed to the mold and includes an axial array of holes. A bore in the sleeve is connected to a source of low pressure gas via a delivery tube so that the low pressure gas can selectively communicate with the interior of the hollow tube as the movement of the tube causes the selective registry of the holes therein with the delivery tube. Such selective registry causes a pressure drop in the delivery tube which is measured by a pressure drop detector and accompanying recorder. Electrical leads are provided on the inner surface of the mold for evaluating when the distortion of the blank causes the face of the blank to reach selected portions of the mold inner surface.

Abstract: A flat blank of a metal which becomes superplastic at elevated temperatures is transformed into a part of the desired configuration in an apparatus that is utilized in connection with a hydraulic press, the apparatus having a lower section that is mounted on the press bed and an upper section that moves with the press ram. The lower section includes a forming tool having a contoured surface, the configuration of which corresponds to that which is to be imparted to the blank, and a cooling passage that surrounds the tool. The blank is positioned over the tool and cooling passage of the lower section. The upper section includes a chamber enclosed by walls and a bulkhead, another cooling passage at the lower end of the chamber walls, an infrared emitter within the chamber, and infrared optical sensors that are located outside of the chamber but view the blank through tubes that extend through the bulkhead and the emitter.

Abstract: An improved method of manufacturing a rupture disk containing one or more scores or perforations from a sheet metal section comprising the steps of cutting the sheet metal section into a disk, forming a concave-convex dome in the disk by applying pressurized fluid to one side thereof, and then forming one or more scores or perforations in the concave-convex dome of the disk while continuing to apply pressurized fluid thereto. Automated apparatus for carrying out the method of the invention is also provided.

Abstract: A hydrostatic extrusion apparatus whereby semicrystalline thermopolastic polymers can be hydrostatically extruded in a solid state is described. The apparatus includes an outer tooling support means; a container assembly aligned within one end of the outer support means and having pressure means contiguous therewith whereby pressure is applied to the apparatus to both rigidly align the tooling and provide sufficient pressure for extrusion of a polymer billet within the container assembly and a receiver assembly coaxially aligned with the container assembly in the other end of the tooling means. The container assembly includes a container means, sealing means to prevent leakage of hydrostatic fluid in the container means and a die portion on the inner forward surface of the container means. The receiver assembly includes a concentrically aligned mandrel which supports and aligns a mandrel-head in spaced relationship with the die portion of the container means.

Abstract: The present invention relates to improved methods and apparatus for manufacturing scored reverse buckling rupture disks. The scores on the disks radiate outwardly from central portions thereof toward the peripheries thereof and have known depths and depth variances.

Abstract: An improvement to an apparatus for and method of making structures from at least one workpiece is disclosed. The prior art apparatus and method comprised a pair of dies which were clamped about the periphery of the at least one workpiece creating a gap therebetween. A pair of non-inflatable platens were then used to apply a force against the pair of dies further clamping the workpiece in place. The die assembly and workpiece were then heated to forming temperatures and thereafter the workpiece was formed within the pair of dies by fluid under pressure. Typically the forming was Superplastic Forming or Superplastic Forming/Diffusion Bonding. The improvement to the apparatus and method comprises providing an inflatable platen between one of the dies and one of the non-inflatable platens, adapted to regulate the force applied by said pair of dies to said at least one workpiece.

Abstract: Device for the control of the pressure in the pressure chamber for the hydromechanical deep drawing of sheet metal in hydraulic presses wherein the pressure chamber constitutes the drawing die. The control system has at least one two-diametered piston transmitter mounted in a hydraulic cylinder which on the side of the smaller diameter of the piston of the piston transmitter is connected to the space of the pressure chamber and on the other, larger diameter side of the piston transmitter is provided with a supply line for the pressure medium. The control system may include several hydraulic cylinders with two-diameter piston transmitters, the volume of the parallel hydraulic cylinders at the side of the smaller diameters of pistons of the piston transmitters is equal to, or greater than, the volume of the pressing in the pressure chamber.

Abstract: An insulation arrangement in which a sheath (2) having at least one thin deformable wall (3), for example of foil, contains a powder insulating material (10), with a high vacuum within the sheath. The vacuum can be drawn through an opening (8) after a filter (9) is inserted to prevent removing the powder when the vacuum is drawn. The insulation arrangement can take the form of a panel or a pipe, and the thin wall (3) can be mechanically deformed after the vacuum is drawn.

Abstract: The invention concerns a process and device for the manufacture of blisters with high barrier properties using metal-plastic composite foils which can be deep drawn, in particular an aluminum-plastic composite foil which is clamped firmly in the clamping facility of a device for manufacturing blisters. The process is such that the composite foil is pre-stretched in a first step and then shaped into a blister in a second step.

Abstract: A machine for use in forming ductile metal sheets into shaped bodies having first and second open-ended, annular chambers which are relatively movable, while maintaining their open ends in register with one another, between a position in which the open ends meet and a position in which the open ends are spaced apart, a plate in at least one of the chambers which is movable independently of both chambers in directions parallel with the directions of relative movement between the chambers between a first position in which it constitutes a gas tight sealed base for said one chamber and a second position in which it is adjacent the open end of that chamber.

Abstract: An apparatus for calibration of tubular articles, especially cylinder linings for internal combustion engines, manufactured through isostatic compression of pulverulent metallic materials, comprises piston means for effecting an axial displacement between the tubular article and a mandrel which it surrounds during the calibration. Preferably, the tubular article is first subjected to a rather modest radial inwardly directed pressure which is increased after an axial relative movement between the mandrel and the tubular article has taken place.

Abstract: A method is disclosed for removing a part from a die, the part having been produced by clamping a preform between first and second dies and forming at least a portion of the preform into a cavity of the first die. The method comprises the steps of drawing a vacuum from between at least a portion of the formed preform and the second die and separating the second die from the first die such that the part is withdrawn from the cavity of the first die. In a preferred embodiment, wherein the part is clamped abouts its periphery, the method involves the additional steps of providing a channel about at least a portion of the second die aligned with and in communication with the periphery of the preform, and providing sealing members to seal off the channel. The vacuum is then drawn from the channel.

Abstract: A hydrostatic extrusion apparatus whereby thermoplastic polymers can be hydrostatically extruded in a solid state is described. The apparatus includes:(a) an outer casing or tooling support means,(b) a container assembly concentrically contained within the outer casing and having pressure means attached thereto to provide extrusion pressure to a fluid in the assembly, sealing means to prevent leakage of the fluid, means for holding a polymer billet and including a die portion, and(c) a receiver assembly axially aligned with the container assembly concentrically within the outer casing having pressure means to clamp the container and receiver assemblies together, a mandrel for holding and aligning a mandrel-head in spaced relationship with the die, and means for receiving, lubricating and cooling the extrudate.Optionally, means for preheating and loading the polymers into the container assembly are provided whereby the press may be operated on a semi-continuous or continuous basis.

Abstract: Apparatus for continuous extrusion has a rotatable wheel with an endless groove therein, a relatively stationary shoe member overlying part of the groove lengthwise, a portion of the shoe member projecting part way into the groove and being constituted at least partly by a die assembly which includes a separate and replaceable abutment member which projects into the groove to block it. The die assembly can have separate and replaceable components constituting a feed chamber, a die throat, and optionally a mandrel supported in the die throat for producing tubular extrusion products. Cooling of the die assembly is also envisaged.

Abstract: A method is provided for eliminating internal voids in superplastically forming parts. A blank of material which is capable of being formed superplastically is held opposite a forming surface of a die. The blank is heated to the superplastic forming temperature and pressure is applied to both sides of the blank. This pressure is sufficient to prevent the formation of voids. The pressure on the side of the blank farthest from the die surface is then increased to superplastically form the material against the die surface. In a second embodiment, the pressure is applied after the blank has been formed either by maintaining the forming pressure to compreses the material between the forming pressure and the reaction of the die, or by applying a fluid pressure to both sides of the part, thereby removing voids by plastic deformation and diffusion.

Abstract: A sheet of material is held in a die opposite a forming surface of the die, and gas pressure is applied to both sides of the sheet. The pressure creates a compressive stress in the sheet thickness direction sufficient to cause plastic flow. By maintaining the pressure higher on the side of the sheet opposite to the forming surface, the sheet bends and expands toward the die forming surface. This pressure differential can be increased as necessary to bend the sheet into the crevices which make up the details of the forming surface. The sheet may be heated during forming to lower the compressive stress which is required to cause it to flow plastically.

Abstract: An improved continuous hydrostatic extrusion process and apparatus for metals is disclosed. In order to reduce the leaks of viscous fluid through the clearances between the rotor and the stator, which clearances are necessary for operation of the apparatus, the drive fluid used in the groove of the rotor to cause forward movement of the blank is of a higher viscosity than the fluid in the isostatic chamber in which extrusion pressure is present. The pumping power is acccordingly greatly reduced and it is possible to avoid the use of expensive and delicate pressure multiplying means.

Abstract: An apparatus for calibration of tubular articles, especially cylinder linings for internal combustion engines, manufactured through isostatic compression of pulverulent metallic materials, comprises piston means for effecting an axial displacement between the tubular article and a mandrel which it surrounds during the calibration. Preferably, the tubular article is first subjected to a rather modest radial inwardly directed pressure which is increased after an axial relative movement between the mandrel and the tubular article has taken place.

Abstract: Two elongated gripping members (12,12) cooperate to form a closed pressure chamber about a waxed billet (61). The gripping members are reciprocated relative to an extrusion station (13), such reciprocation first moving the pressure chamber toward and past the extrusion station so as to extrude the billet through a die (66) at the extrusion station, and then returning the gripping members, in separated condition, to their initial positions to permit the immediate loading of another billet between the gripping members. Also disclosed are various additional systems, e.g.

Abstract: An improvement to an apparatus for and method of making structures from at least one workpiece is disclosed. The prior art apparatus and method comprised a pair of dies which were clamped about the periphery of the at least one workpiece creating a gap therebetween. A pair of non-inflatable platens were then used to apply a force against the pair of dies further clamping the workpiece in place. The die assembly and workpiece were then heated to forming temperatures and thereafter the workpiece was formed within the pair of dies by fluid under pressure. Typically the forming was Superplastic Forming or Superplastic Forming/Diffusion Bonding. The improvement to the apparatus and method comprises producing an inflatable platen mounted between one of the dies and one of the non-inflatable platens, adapted to regulate the force applied by said pair of dies to said at least one workpiece.

Abstract: A hydrostatic pressing apparatus comprising a container having a cavity for accommodation of a blank and communicating with a high pressure source, and a die and a plug which seal the cavity on opposite sides and which are installed in movable locks. The apparatus has a power frame formed by two slabs which are arranged on opposite sides of the container at a distance from one another which is slightly greater than the container length. The die is arranged outside the container and bears with its lock against one of the slabs, and the plug lock bears against the other slab, the cavity of the container being of different diameters along its length, the diameter being the largest on the plug side so as to obtain at the plug a force sufficient for causing the power frame to move to press the die against the container during hydrostatic pressing.

Abstract: A small and simply operated recording apparatus employing an elastic pressure element is utilized to make a three dimensional recording in thin metallic foil from each of the two sides of a primary key from which a secondary key is to be manufactured, the recordings placed in an interpreting apparatus, which may be located remotely from the recording apparatus, which permits extraction of precise three dimensional data stored in the recordings whereafter the extracted data is utilized in key cutting apparatus to produce a secondary key, in all comprising a key making system.

Abstract: The invention concerns a process and a device for manufacturing blisters with high barrier properties from a metal-plastic composite foil which can be deep drawn, in particular from an aluminum-plastic composite foil which is held fast in the clamping facility of a device for manufacturing blisters. In shaping the foil into one or more blisters, pressure is applied pneumatically or pneumatically and hydraulically to at least one side of the foil which stretches onto and over a lubricating layer or easy slip plate on the base of a die.

Abstract: Tooling for use in an autoclave or a hot press for the superplastic forming and diffusion bonding of metals which tooling includes upper and lower portions with a labyrinth seal therebetween having inert counterflowing gas introduced thereto to prevent contamination from flowing across the seal to attack the metal being processed.

Abstract: An extrusion machine is disclosed wherein wax or other suitable lubricant is applied to the side of the feedstock contacting the shoe of the extruder. A stick of wax may be supported in a cylinder having an open end facing the feedstock; the stick is a loose sliding fit in the cylinder and compressed gas introduced into the cylinder applies a substantially constant biassing force urging the stick into engagement with the feedstock and at the same time, by leaking between the stick of lubricant and the cylinder, cools the stick of lubricant to inhibit melting.

Abstract: An improvement to the method of making a structure by superplastic forming, wherein portions of a preform are expanded, in the superplastic condition, against a forming member, is disclosed. The improvement comprises the step, prior to expanding the preform, of providing a lower coefficient of friction between the portions of the preform to be expanded and the forming member than which exists between the portions of the preform where expansion is intended to be minimal and the forming member. The two values of coefficient of friction are obtained by applying first and second release coatings to the portions of the preform to be expanded and those where expansion is to be minimal respectively, with the first release coating having a coefficient of friction less than the second release coating. Alternately, the first and second release coatings can be applied to the forming member. The preferred first and second release coatings are boron nitride and yttria respectively.

Abstract: The invention concerns device for the manufacture of blisters with high barrier properties using metal-plastic composite foils which can be deep drawn, in particular an aluminum-plastic composite foil which is clamped firmly in the clamping facility of a device for manufacturing blisters. The process is such that the composite foil is pre-stretched in a first step and then shaped into a blister in a second step.

Abstract: A method and apparatus are provided for continuously extruding rod feedstock through a die orifice while gripping two opposed sides of the feedstock to a pressure greater than the yield strength of the material with means for applying lubricant to the ungripped surfaces, constraining walls between which the feedstock is fed in the gripped condition, a stop at one end of the constraining walls, and a die orifice near the stop through which the feedstock is extruded, said lubricant applying means including at least two cylinders each having an open end facing a respective one of the ungripped surface when the apparatus is in use and means for introducing compressed gas into each of the cylinders.

Abstract: Apparatus for bending a laminated panel about at least one intended bend line extending parallel with the bottom of a notch formed in the backing of the panel. The panel is retained in engagement with a forming edge which extends along and is at least coextensive with the bend line. The panel and the forming edge are supported spaced-apart from a base. A substantially air-impervious membrane covers the panel and cooperates with the base to provide a substantially closed chamber. Means is provided establishing a pressure within the chamber which is less than the pressure outside of the chamber, whereby the pressure outside of the chamber forces the panel to bend about the forming edge thereby to place the panel portions on opposite sides of the bend line in angular relation relative to each other. A method for bending laminated panels is disclosed.

Abstract: A method and apparatus for assembling together a rectangular outer tube, a rectangular inner tube and thin flat elongated panels having their side surfaces solidly abutted between the inner wall of the outer tube and the outer wall of the inner tube. The assembly is expanded by applying an internal pressure of at least a thousand psi into contact with a die cavity of rectangular cross-section. In order to minimize the required expansion of the tubes it is desirable that the inner tube conform as closely as possible to the space between the panels prior to expansion. In order to facilitate insertion of the panels, the inner tube is subjected to a controlled collapse in which its sidewalls are curved inwardly and its corners are displaced radially inwardly to provide additional clearance for insertion of the panels. After insertion of the panels the walls of the inner tube are formed outwardly to fit relatively closely within the space defined by the panels.

Abstract: A method and apparatus are provided for automatically controling the strain rate during superplastic forming of a blank of material into a part. The method and apparatus produce a part in a minimum time by deforming the material in its optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is automatically applied across the thickness of the blank in accordance with the previously determined relationship between time and pressure until the part is formed. The apparatus comprises conduits connected to a die and to a high pressure gas. Valves in the conduits regulate the pressure applied to the blank. A controller receives command signals from a programmer which is programmed with the desired time vs pressure relationship.

Abstract: A method is provided for controlling the strain rate during superplastic forming of a blank of material into a part. The method produces a part in a minimum time by deforming the material under suitable-optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is applied to the blank in accordance with the previously determined relationship between time and pressure until the part is formed.

Abstract: A method, apparatus and process for forming an elongated product of unlimited length is disclosed. The method consists of gripping and feeding a material of unlimited length between two toruses whose toroidal surfaces have suitable shaped grooves to accommodate the incoming material. The toruses are so constructed that each of them can sustain a radial deformation substantially in excess of 0.2 per cent without undergoing a permanent plastic set. The toroidal surfaces of the two toruses are radially squeezed against each other so as to cause a temporary radial deformation in both toruses substantially in excess of 0.2 per cent but less than an amount that causes a permanent set in either torus. This creates a contact length between the two toruses. Such squeezing also causes a three dimensional stress distribution in the grooves which stress is substantially hydrostatic. A deformation control element with a suitably shaped aperture or apertures is located substantially in the center of the length of contact.

Abstract: Two rotors cooperate to advance a rod of indefinite length continuously into an extrusion die. Portions of radially extending surfaces of the two rotors are utilized to grip the rod therebetween, in order to effect such advance of the workpiece rod upon the simultaneous rotation of the two rotors. An annular groove extends along the appropriate radially extending surface of one of the rotors. Such annular groove serves to retain the rod therein while guiding rhe rod along a path leading to the die. The face-to-face arrangement of the two rotors along their respective radially extending surfaces permits a very high extrusion pressure to be supported, while also allowing effective sealing of the annular groove at such very high extrusion pressure.

Abstract: Disclosed is a mandrel for a high pressure tube extrusion press. The mandrel comprises a tip member providing a tip adapted to be positioned in the die opening of the press to present an annular gap for tube extrusion, and a carrier for the tip member. The carrier has a threaded central tip member receiving bore for threadably receiving a threaded segment of the tip member therein. A divided ring shaped element is disposed between a flange on the tip member and the carrier in an annular space provided at the mouth of the bore to facilitate the assembly and disassembly of the mandrel and prevent inadvertent separation of the tip member from the carrier.

Abstract: In a press for the hydrostatic extrusion of tubes, including a mandrel unit permanently inserted in the pressure chamber of the press and being movable between two axial positions, the unit comprising a mandrel and a tubular sleeve which during the extrusion transmits forces acting on the mandrel to a force-absorbing unit in the press, the sleeve being so constructed as to form an annular gap between the sleeve and the pressure chamber wall, and a stop ring in the gap forming an interference fit with the pressure chamber wall, the sleeve having stop faces thereon designed to cooperate with end faces of the stop ring so as to determine the limit positions of the axially movable mandrel unit.

Abstract: An improved method and apparatus for shaping sheets of thermoplastic material is disclosed in which sheets are pressure molded against a mold member by the direct application of a liquid coolant under pressure thereto. The coolant contacts the surface of the sheet and upon pressure reduction vaporizes and accordingly, due to the heat of vaporization effect, rapidly absorbs a large amount of heat from the sheet so as to form a solidified skin on the outer surface of the sheet after or simultaneously with the shaping of said sheet. The sheet thus remains in the mold for a shorter dwell time inasmuch as the sheet becomes more quickly shape retentive because of the rapid cooling. This accordingly permits smaller and less bulky equipment to be utilized in sheet shaping processes. The attendant reduction in equipment size can result in substantial cost savings for such equipment.

Abstract: The pressure medium used in the pressure chamber of a hydrostatic press is degassified in a degassing tank prior to delivery to the pressure chamber so as to improve the resistance of the pressure cylinder, or the liner inside of the pressure cylinder, to fatigue. The degassified pressure medium can be a mixture of recirculated pressure medium recovered after passage through the die extrusion hole and new pressure medium, such as castor oil.

Abstract: A method and apparatus are provided for automatically controlling the strain rate during superplastic forming of a blank of material into a part. The method and apparatus produce a part in a minimum time by deforming the material in its optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is automatically applied across the thickness of the blank in accordance with the previously determined relationship between time and pressure until the part is formed. The apparatus comprises conduits connected to a die and to a high pressure gas. Valves in the conduits regulate the pressure applied to the blank. A controller receives command signals from a programmer which is programmed with the desired time vs pressure relationship.