Method and apparatus whereby complex patterns are pressed into the interior of a part formed of compactible material. A flexible, pre-fabricated pattern form bearing the inverse of a desired pattern is wrapped around a conventional mandrel and this assembly is loaded inside of an isostatic pressing bag with a material charge. After compaction, the mandrel is separated from the pattern form, leaving the pattern form behind in the compact. The pattern form is then peeled, pulled, or otherwise removed from the interior of the compact, leaving behind the desired on the compact interior. Alternatively, a collapsible or melt-away mandrel with the inverse of a desired pattern formed on its exterior is employed to form the desired pattern on the interior of a compacted part.
BACKGROUND OF THE INVENTION
This application is a continuation of application Ser. No. 700,535, filed May 14, 1991 now abandoned. Which is a continuation in-part of abandoned U.S. application Ser. No. 07/669,055, filed Mar. 14, 1991, assigned to the assignee hereof.
A process for producing high density refractory metal warhead liners from near net shape blanks. A shaped mold is filled with pure or solid solution molybdenum or tungsten powders. The powders may be isostatically pressed and sintered to form a near net shape blank. A hot isostatic press may be used in combination with these steps or by itself to form the near net shape blank. The hot isostatic press densifies the near net shape blank to at least 90% of theoretical density. Where wrought properties are desired, a final forging step is performed. Alternatively, a process such as vacuum plasma spraying may be used to form the near net shape blank. A hot isostatic press densifies the near net shape blank. A final machining step achieves a finished refractory metal warhead liner.
A hot-isostatic press comprising a load-carrying member (1) adapted to be supported by a substantially annular support member. The annular support member is arranged on an underlying support (4) and encloses a heat insulation (10). Further, at least part of the annular support member is arranged in the form of a number of axial segments (3), which are arranged side-by-side and are connected at the top and bottom to adjacent members by means of an attachment which guides the segment in a hinge-like movement relative to adjacent members to take up the radial movements which arise in the segment as a result of the temperature gradient between the upper and lower parts of said support member. The height of the heat insulation corresponds at most to the beginning of the axial segments. (FIG. 1 )
An implant having an integrally-textured, hemocompatible blood-contacting surface and a method for producing the same is provided. The implantable device can include a device body having a textured surface and a predefined complex shape, such as a bladder or a generally U-shaped conduit. The device body can be composed of a first device material, and the textured surface can be formed of a second device material on the obverse side of the device. The textured surface can have multiple, blood-compatible structures integrally formed thereon. The structures can be fibrils that are suitable for a generally uniform biological layer to be established thereupon. The method for producing an implantable device can include the steps of fabricating a mold; applying a flock to the mold; introducing a conformable dissoluble material to the mold; removing the dissoluble material from the mold; removing the flock from the dissoluble material using a first solvent thereby creating a dissoluble device form having a form surface having multiple invaginations therein; applying a layer of a selected device material to the dissoluble device form thereby providing a device wall with the structures being integrally formed thereon; and removing the dissoluble device form from the device wall by liquefying the device form, thereby providing the implantable device.
Pressure is measured inside of a high pressure vehicle. A substance is compressed at a first pressure to create a preform having a first density. The preform is placed inside of a high pressure vessel and subjected to a second pressure, greater than the first pressure. The preform therefore changes in density to a second density, greater than the first density, whereby the second pressure can be determined. The method may also be used in determining the pressure inside of a food product during food processing and a high pressure vessel.
A process is disclosed for forming a pressed metal part in which a preform is inserted into a pressed metal mold. The mold is then filled with powdered metal. The powdered metal and preform are compacted to create a compacted metal part wherein the preform defines an adjacent volume next to the compacted metal part. The compacted metal part is ejected from the mold and sintered to create a sintered metal part. The preform is removed by the sintering step in such a way that the adjacent volume becomes a void region. The preform can be formed of copper so that, upon sintering, the preform is removed from the sintered metal part through infiltration. Alternatively, the preform can be formed of zinc so that, upon sintering, the preform is vaporized and thereby removed from the sintered metal part. The void region created by the removal of the preform can be an undercut, a taper, an annular groove, a thread or an internal cavity. In this way, the present invention eliminates the need for machining such surfaces as has been necessary using previous compaction methods.
