Abstract: In a method for producing a three-dimensional object wherein the object is generated by successive solidification of individual layers of the object from a liquid or powdery material by action of electromagnetic radiation, the problem arises that the object is either distorted due to shrinkage of the material or that the quality of the surface of the object is poor when using a corresponding shrinkage reducing construction. For the solution of this problem, each layer is separated in an inner core region (2) and an outer shell region (3) and the action of the radiation is controlled in the core region and in the shell region for generating different properties of both regions.

Abstract: A composite material blank for an orthotic insert. The device is formed of layers of fiberglass and graphite fiber material. A first graphite fiber layer provides the overall structure with increased strength, while secondary graphite fiber reinforcement strips are arranged below the first and fifth rays of the foot to provide additional rigidity and control in these areas. The edges of the graphite fiber layers are recessed inwardly from the edges of the fiberglass layers so as to provide a graphite-free border which prevents cracks from propagating into the graphite fiber layers. The layers are bonded together by heat curing.

Abstract: In a method for producing a three-dimensional object by successive solidification of superposed layers of the object a deformation of the object caused by shrinkage during the solidification shall be reduced. To this end first of all respective partial regions (6a . . . 6k) of a layer are solidified and simultaneously connected with underlying partial regions of the previously solidified layer to form multilayered cells and thereafter adjacent partial regions of the same layer are interconnected by solidifying narrow connecting regions (8a . . . 8p). The intermediate regions (7) between the individual partial regions are solidified by post-curing.

Abstract: A method of replicating surface textures by providing a laminar, dimensionally stable, flexible mold having an impression of the surface texture to be formed on one side thereof, applying a layer of fluid casting material to the flexible mold, and partially curing the resinous material wherein the impression is transferred to the partially cured resinous material. The flexible mold and layer of partially cured resinous material are then secured to a recipient surface, and the material is fully cured, and the flexible mold removed, leaving a surface texture on the recipient surface.

Abstract: A method of producing a form-stable sintered porous shaped phenolic resin article with continuous open pore structure and high macroporosity, in which a phenolic resin mixture is partially cured to a solid which is then comminuted to give a comminuted resin. The comminuted resin is admixed with water, hexamethylene tetramine and a cellulose ether, and the resulting comminuted resin mixture is formed into a shaped article which is allowed to come to equilibrium with air having a relative humidity of less than 100% at a temperature below 100.degree. C. The shaped article is then sintered to produce a form-stable sintered porous product.

Abstract: Glass fiber mats are made for subsequent use in preforming for an RTM or SRIM molding process, for example, such that the binder applied to the mat has two distinct curing stages. In the first stage, a partial cure is provided by visible light upon a free radical generation in response to a photoinitiator mixed in the binder in an exact ratio to give a predictable increase in viscosity to that of a semi-solid so that the fibers are sufficiently bound for subsequent handling, but not sufficient to complete a cure, while leaving a second stage ready for a final cure which is achieved by the use of a cationic-type second photoinitiator which is sensitive to ultraviolet light. During the second curing stage, the mat is formed into a three-dimensional shape of a desired end product and cured with ultraviolet radiation while still in the mold, to obtain a rigid three-dimensional preform structure.

Abstract: An improved method for stereolithographically forming a three-dimensional object wherein ordinarily solidified internal walls of the object remain at least partially unsolidified. Any unsolidified medium within the object can be drained from the internal walls of the object prior to post-curing so that a hollow three-dimensional object is formed. The object is formed on a layer by layer basis with the internal portion of each layer of the object formed as a grid of solidified portions and unsolidified portions wherein the solidified and unsolidified portions are different on each layer. Objects formed in this manner can be used as patterns in investment casting.

Abstract: A process for producing a concrete post having a sleeve that functions as a pouring form during pouring of the posts, a protective shield during shipping and storage thereof, and a strengthening component upon installation. The post is produced in a process whereby multiple, replacable sleeves are provided in a rack which are simultaneously filled from a hopper. The sleeve cavities are substantially free of rebar to facilitate pouring and reduce cost, the sleeve replacing the rebar as the strengthening component.

Abstract: A tire is manufactured by assembling a tread package into a pattern ring and molding a tread thereon while partially precuring the package. The tire is further assembled by positioning an uncured carcass within the pattern ring so that the carcass contacts an uncured portion of the tread package. Finally, the assembled tire is separated from the pattern ring and subsequently heated in a mold devoid of a tread pattern to bond and cure the complete tire.

Abstract: An improved method for stereolithographically making an object by alternating the order in which similar sets of vectors are exposed over two or more layers. In another method, a pattern of tightly packed hexagonal tiles are drawn. Each tile is isolated from its neighboring tiles by specifying breaks of unexposed material between the tiles. Using an interrupted scan method, vectors are drawn with periodic breaks along their lengths. In another method, modulator and scanning techniques are used to reduce exposure problems associated with the acceleration and deceleration of the scanning system when jumping between vectors or changing scanning directions.

Abstract: According to the invention, calibrated rings are obtained by superficially vulcanizing extruded or profiled extrudate at the exit of an extrusion head (T), then by cutting this vulcanized extrudate into portions by means of a conical cutting device (C), subsequently by butting the two ends, in the respective form of a conical tip and a funnel, of each portion (t) together under hot conditions and under a controlled pressure, in order to obtain a ring blank which is then engaged between the half-cavities of a mold (Mo), where it undergoes shaping and vulcanization by the heating of the latter and thereafter deburring as a result of a shearing action produced by a push device (D) causing the half-cavities to slide in the closed position in the frame of the mold, before causing the opening of the latter by means of a device (G) and the release of the calibrated and superficially clean ring obtained.

Abstract: Forming process, during vulcanization on a mandrel, of the end portions of rubber tubes, using a tool having a radially deformable skirt in the form of a corolla, made of vulcanized rubber which encloses the end portions of rubber tubes using solely the action of the circumferential elasticity of its corolla. The disengagement of the part after vulcanization is accomplished by a simple axial thrust on the corolla. An upturned position of the radially deformable skirt makes possible the installation of the rubber tubes and other preparation operations.

Abstract: Porous shaped phenolic resin articles are made by partially curing a phenolic resin to a solid, comminuting the resin, forming into a predetermined shape, and sintering. Porous shaped carbon articles are made by carbonizing the sintered material.

Abstract: A fiber/resin composite whose resin phase is formed by at least initial actinic radiation curing of a resin composition comprising an actinic radiation curable first resin component and a second resin component which is non-cured under curing conditions effective for the first resin component. The actinic radiation exposure of the fiber/resin composition effects curing of the first resin component to immobilize the composite and impart structural integrity thereto, whereby the composite may be handled, packaged, or further processed. Filament wound, braided, and pultruded articles are described, together with associated methods for forming such articles by filament winding, braiding and pultrusion. As a specific embodiment, a solid fuel rocket motor is disclosed comprising a solid fuel body in a filament wound fiber-resin composite casing formed by filament winding of the solid fuel body with resin-impregnated filament or rovings thereof.

Abstract: A molded article of methacrylic resin formed of a cross-linked polymer having at least part of the surface thereof coated with an abrasion resistant layer in contact with a basic molding material made of a methacrylic partially cross-linked gel thereby allowing the methacrylic partially cross-linked gel consequently produced to possess the property of retaining the polymerization in a stopped state, and simultaneously polymerizing said two materials held in mutual contact under a condition capable of imparting a desired shape to the combined materials.

Abstract: In a process for the production of smooth surfaced parts, a paste material, which includes paste or granule pieces which are coated with added pigment and then pressed back together, is applied, in the form of an extrusion or a coating, to a substrate. The extrusion or coating is subjected to a first, incomplete hardening, after which it is no longer flows freely under its own weight. The surface layer, containing added pigment, is then removed from a surface to be used. This surface is subsequently smoothed, and the hardening of the coating to form a hard material is completed. The smoothing and the completion of the hardening can occur in the same processing step as a shaping for the formation of separable shaped parts. The substrate can be inseparable from the hardened coating. The surface layer, containing added pigment, can be removed by mechanical means, solvents or abrasion by a suspension in liquid or air, if appropriate in the presence of ultrasound.

Abstract: An analytical technique for controlling the curing process of fiber-reinforced composite materials that are formed using thermosetting resins. The technique is the percent gel method and involves development of a time-to-gel equation as a function of temperature. From this equation a rate-of-gel equation is then determined, and a percent gel is calculated which is the product of rate-of-gel times time. Percent gel accounting is used to control the proper pressure application point in an autoclave cure process to achieve desired properties in a production composite part.

Abstract: A method of making a fiber reinforced part by compression molding under heat and pressure a glass fiber reinforced thermosetting resin composition at an initial high pressure for a short period of time and then substantially reducing the pressure for a longer period of time to form an almost cured FRP part at which time there is applied to the exterior or outer surface of the FRP part an in-mold coating composition and heat and pressure are continued to cure the in-mold coating composition and to complete the cure of the FRP part. During the molding process the temperature gradient across, or the temperature non-uniformities of, the molding or working surfaces of the mold halves is less than about 5.degree. C.

Abstract: A method of preparing a plurality of thermoset resin preforms by extruding a rod, cooling the rod to retain its dimensional uniformity and to reduce further curing of the resin, forming a plurality of grooves in the rod, and fracturing the rod at the grooves to yield the preforms.

Abstract: A process and apparatus for molding a plurality of articles of hardenable material such as plastic which requires each article to be maintained under heat and pressure for a cure interval. A molding press is utilized wherein there is placed a first open mold assembly having spaced die halves between supporting mold platens. At least one of the die halves has a resilient pressure pad between the die and the mold platen supporting the die half. The press is closed to maintain the mold platens in a first force applying position having a slight gap between the die halves and locking the platens in the first position. The mold assembly is removed while in its first locked position from the press and gas from the curing material is evacuated through the gap between the die halves while heating the material.

Abstract: A novel process is provided for producing prefoam type cellular concrete articles, which uses a foamed slurry (E) consisting essentially of an aqueous slurry (A) of a calcium silicate-based cement compound, an aqueous slurry (B) of a calcium aluminate-based cement compound, a specific setting retarder (C), and an aqueous foamed liquid (D). The process is further characterized in that: (i) the foamed slurry (E) is cast and provided with hardened strength sufficient for demolding in 20 to 120 minutes after it has been poured into a mold; (ii) the demolded article is subjected to precuring under specific conditions of humidity, temperature and precuring time; and (iii) the molded article is then subjected to hydrothermal curing under high pressure.

Abstract: A method of manufacturing finished articles of flexible plastic material includes formation of a sheet of plastic material with a first portion having a raised pattern on one surface thereof and at least partially curing the sheet. The first portion having the raised pattern is removed from the sheet and a second portion of plastic material having a raised pattern on one surface and of a color contrasting with that of the first portion is formed in that area of the sheet from which the first portion was removed. A plastic backing layer is formed on the sheet and the article thus formed is cured. The backing layer may be of a color contrasting with that of the second portion of plastic material, or the first portion may be allowed to remain and its back surface may be coated with a layer of plastic of a color contrasting with that of the first portion after which the backing layer is applied.

Abstract: A continuous molding method is disclosed as providing a sliding seal chamber in which moving molding surfaces form and can provide means for the induction of such temperature changes required to produce finished products from the chosen raw material.

Abstract: A method of forming a spark plug boot which utilizes an extrusion process. An elastomeric tube is extruded, then heated to a partially cured condition. The tube is then cut into individual pieces. The individual pieces are stretched over a pin which has at least one external shoulder. The pin and tube are then heated to a temperature and for a time to provide a final cure. The tube is stripped from the pin. The compression set and shrinkage results in an internal shoulder in the tube, allowing it to serve as a spark plug boot.

Abstract: Novel resin products produced by reacting unique polycyclic, aromatic, polycarboxylic acid products with low molecular weight polyols display satisfactory toughness properties and good Barcol hardness values. The process for preparing these novel resin products first involves preparing an intimate, finely divided mixture comprising the acid product derived from the nitric acid oxidation of naturally occurring solid carbonaceous material, a roughly equivalent amount of a liquid polyol, and a suitable acid catalyst. The mixture is then subjected to a precure step which involves heating at temperatures between 80.degree. and 150.degree. C. for from about fifteen minutes to about four hours. The precured mixture may thereafter be subjected to suitable molding conditions at a temperature below about 220.degree. C.

Abstract: A method of making stressed concrete articles made from a cement containing as an additive to portland cement a mixture of alumina cement, calcium sulfate and ground caustic lime, the method including hydrothermal treatment at 50.degree. C or above followed by curing in cold water for several days.

Abstract: A process for molding a tire having a wide bearing surface comprising the steps of molding reinforcing shoulders in a static mold and partially curing the molded materials; removing the partially cured shoulders from the static mold and placing them in a rotating mold; introducing additional plastic material into the rotating mold and rotating the mold; and then heating the mold to complete the curing of the shoulders and to fully cure the additional plastic material to form the tire casing.

Abstract: Method of making a reinforced pneumatic tire in which the tire body is formed in at least two sections each including a side wall and a plurality of annular bands each including an annular reinforcing belt embedded in an elastomer. The tire sections are assembled in a mold with the annular bands of each section interleaved with the annular bands of another section and the elastomer is cured to form an integral tire body. The tire may be formed of two reinforced sections with the interleaved bands forming the annular tread section of the tires, or as three reinforced sections, including two sections each including a side wall and annular bands and a connecting section including annular bands with reinforcing belts which are interleaved with the annular bands of the other two sections to form a tread section. An annular, elastomeric tread section may be formed separately and bonded around and to the annular bands of the reinforced sections.

Abstract: Process of lining aerosol can valve mounting cups with a gasketing composition comprising a carbon dioxide blocked polyamine dispersed in a liquid polyurethane prepolymer consisting of a free isocyanate group-containing reaction product of a polyisocyanate compound with a polyhydroxy material. The lined cups are heated for a few minutes to gel the gasket and full cure subsequently takes place without further intervention by means of ambient atmospheric moisture. The process is rapid, economical in equipment and produces gaskets which permit a significant extension of swaging specifications.

Abstract: Methods for forming a composite ring having unidirectional filaments embedded in a polymer matrix is disclosed. The filaments are spirally wound within the ring to form a plurality of essentially circular hoops which are in coaxial alignment with the expected lines of principle force. In one embodiment the formed ring is structurally integrated into the rotor of a gas turbine engine to reinforce the rotor and to restrain the rotor blades which extend outwardly of the ring.