Abstract: Molding apparatus (10) is provided which allows use of a particulate non-liquid molding material (121) to produce a variety of articles, such as frustoconical barrel segments (122). The apparatus (10) includes a female mold segment (18) including generally annular inner and outer sidewalls (70, 76) and a complemental male mold section (20) having an annular sidewall unit (30). In use, a molding material (121) is placed between the sidewalls (70, 76) and the section (20) is shifted so that it telescopes within the section (18); this compresses the material (121) to a desired final shape, which is then hardened to yield the final product (122). An optional wear insert (26) can be used with female mold section (18), which can be replaced as needed and assists in cleaning of the apparatus (10).

Abstract: A method for producing a silicon ingot having a directional solidification structure comprising the steps of: placing a silicon raw material into a crucible of a melting device constructed by mounting a chill plate on an underfloor heater, mounting a crucible with a large cross-sectional area on the chill plate, providing an overhead heater over the crucible, and surrounding the circumference of the crucible with a heat insulator; heat-melting the silicon raw material by flowing an electric current through the underfloor heater and overhead heater; chilling the bottom of the crucible by halting the electric current through the underfloor heater after the silicon raw material has been completely melted to form a molten silicon; chilling the bottom of the crucible by flowing an inert gas through the chill plate; and intermittently or continuously lowering the temperature of the overhead heater by intermittently or continuously decreasing the electric current through the overhead heater, and an apparatus for pro

Abstract: A tire T is vulcanized by heating the tire T from both an outer forming surface So of an outer mold 2 for forming an outer surface of the tire T and an inner forming surface Si of an inner mold 3 for forming an inner surface of the tire T. The inner forming surface Si is divided into a plurality of inner forming surface portions Si1, Si1 and Si2 in accordance with portions of the tire T, and the inner mold 3 is provided with heaters 5U, 5L and 5M capable of heating the inner forming surface portions Si1, Si1 and Si2 at different temperatures. Since the tire is vulcanized while varying the heating temperatures from inside of the tire in accordance with the portions of the tire, it is possible to vulcanize each of the portions of the tire under optimal temperature condition without generating uneven temperature between upper and lower portions, and it is possible to enhance the performance of the tire.

Abstract: An isothermal golf ball core molding platen is characterized by the use of isobars for even temperature distribution across the surfaces of the platen. The platen is formed of metal and includes first channels which receive heating elements for heating the platens. Isobars are arranged in second channels adjacent to the first channels. The isobars include an outer sheath defining an evacuated chamber and an inner metallic wick. The isobar is charged with working fluid which changes phase with the application of heat. The phase change provides higher speed heat transfer to eliminate temperature gradients within the platen.

Abstract: Mold cycle time is accelerated by employing thermally insulating surface temperature boosters, which are of a minimum thickness to promote cooling by heat transfer through the boosters. According to the thermal transfer properties of the insulating boosters and the respective temperatures of the molten material and the dies, the temperature of the cavity surface is raised by contact with the molten material to equal or exceed the temperature required to produce a molded article, preferably just until the time that the mold is fully filled. Heat transfer through the boosters to the dies then cools and solidifies the molded article until it can be removed from the mold. The temperature boosters result in increased cavity surface temperatures, such that the mold dies can be kept at substantially lower temperatures. The overall result is a reduction in mold cooling time and therefore acceleration of mold cycling.

Abstract: A plate shaped compression mold, a process for producing the same and a process for making laminate therewith. The plate-shaped compression mold for producing sheet laminate including synthetic resin with a metal coating on at least one surface thereof has a surface for contacting the metal coating of the sheet laminate, which surface has a Rockwell C hardness of higher than about 44 and a thermal coefficient of linear expansion which differs from that of the metal coating by not more than about 2.5×10−6/K, thereby substantially preventing warping or wrinkling of the metal coating during the compression molding process.

Abstract: A vacuum debulking table for fiber reinforced thermoplastic prepreg includes a base, a base table mounted to the base, and a platen mounted to the base table. The platen has a frame and the base table includes a vacuum aperture located within the frame. A vacuum pump is connected to the vacuum aperture. The platen includes a heat generator. The table further includes tooling conforming to the frame and a kit to be debulked. A pair of opposing pressurized cylinders is coupled to the base at a first end. A top cover is mounted to the base and attached at a second end of the opposing pressurized cylinders. The top cover includes a flexible bladder. An insulator is mounted to the base table surrounding the platen. An insulation cover blanket is configured to be drawn between the insulator and top cover. An activation switch activates a programmable controller connected to the pressurized actuator control, the heat control and the vacuum control.

Abstract: A process for forming molded articles from particulate thermoplastic material, the process comprising:

Abstract: Method and apparatus for making and coating a plastic lens. Oxygen barrier containing photoinitiator is used to cure incompletely cured lens portions. Radiation pulses are used to control lens curing rate. Lens is postcured while in a mold cavity using a conductive heat source.

Abstract: A plastic article is formed in an injection mold by injecting molten plastic into the injection mold at an elevated temperature, cooling the plastic from the molten condition to a solid condition, and crystallizing a portion of the plastic by slowing down the cooling of said portion.

Abstract: An improved bushing mold is disclosed for an apparatus for welding a battery terminal post to a battery bushing. The battery terminal post is electrically connected to a battery plate disposed within a battery case and the battery bushing is secured to a battery case cover with the bushing having a central bushing aperture for receiving the battery terminal post therein when the battery case cover is located on the battery case. The bushing mold comprises an electrically conductive mold body having an insulating mold insert. The mold insert comprises a first and a second insert portion with the second insert portion being replaceable independent of the first insert portion.

Abstract: A unique composite material impregnated with a heat curable resin comprising a layer of conductive fibers and one or more resin carrying layers is utilized to reinforce utility poles by wrapping the material around a portion of the utility pole and causing a current to flow through the conductive fibers to resistively heat the material to the resin. The composite material can also be incorporated into molds to produce cured composite parts. The composite material is also used in the construction of large parts without the need for huge, expensive molds. The conductive fibers in composite parts are oriented in a manner to ensure that the entire part is thoroughly heated during the curing process.

Abstract: A voltage is applied to a feeder plate (29) from a power source section (2) including an alternating power source for dielectric heating, whereby an electric field in a direction crossing a direction in which a mold (8) is moved is applied to an incoming plate (28) which is not in contact with the feeder plate (29), so that molded object materials (9) are heated and expanded. By doing so, arc discharge caused by contact of the mold with an electrode is prevented from occurring during the heating and molding of a biodegradable molded object by dielectric heating.

Abstract: A method of molding a composite insulator having a core member and an overcoat portion arranged on an outer surface of the core member, in which a core member having metal fittings at both ends thereof is set in a metal mold for molding the composite insulator, overcoat portion forming materials are filled in a cavity for molding said overcoat portion formed around the core member, and then the overcoat portion forming materials are cured by heat, is disclosed. The improved method includes a step of making a temperature increase of the overcoat portion forming materials near the metal fittings equal to that of the other portion, when the overcoat portion forming materials are cured by heat, by utilizing an additional heating means.

Abstract: A mould apparatus for moulding materials such as thermoplastics includes a first layer of mould material and a second layer contiguous to the first layer. The second layer contains heating devices such as resistance wires, whereby in use, the heating devices heat the second layer so as to transfer heat to the first layer.

Abstract: A constructed wall structure and method of fabrication that replicates a wall formed by nature. The structure has a plurality of discrete layers, with each layer constructed of concrete and a decorative additive. Every layer has an interface with an adjacent layer to thereby form a plurality of interfaces wherein at least one, and preferably most or all, of the interfaces are non-level. Non-limiting examples of decorative additives are rocks, sea shells, colorants, and mixtures thereof. Methodology for fabricating the wall structure includes pouring a first concrete mixture into a substantially vertical form which can be constructed as a channel within a generally elongate mound of a naturally occurring material and thereafter permitting a top surface of the concrete mixture to assume a non-level configuration. Preferably, a joint forming material is placed on the top surface of this first concrete mixture.

Abstract: Demolding apparatus for reliably and repeatedly mechanically separating contact lens mold assemblies without damaging the contact lens formed therebetween. The mold assembly includes a frontcurve mold having a central mold section with a surrounding flange, and a corresponding backcurve mold also having a central mold section with a surrounding flange, with a contact lens being molded therebetween. The demolding apparatus includes a conductive heating probe which contacts the backcurve mold of the lens mold assembly to conductively heat the backcurve mold. Heat is conducted by the backcurve mold to cause a temperature gradient between the backcurve mold and the lens being demolded. The temperature gradient causes a differential expansion and shifting of the surface of the backcurve mold relative to the surface of the lens to lessen the adhesion therebetween to assist in separation of the molds, while leaving the lens in the frontcurve mold.

Abstract: A formwork constructed of prefabricated elements, preferably for building a concrete wall. The formwork has two parallel walls that define a space that is filled with concrete laden with water, sand and large aggregates. An inner wall of the formwork has a lattice or perforated structure to filter and pass water and small aggregates from the space that is filled with concrete. An outer wall also has a lattice or perforated structure to filter additional water and smaller aggregates from the space that is filled with concrete. This invention also includes a concrete heating wall that may be constructed from formwork.

Abstract: A shaping mold for the production of ultra-thin shaped rubber articles, has a main body which is dipped into a latex liquid so as to make the latex adhered to the surface of the main body. The adhered latex is heat-dried to form an ultra-thin shaped rubber article over the surface. The mold is such that at least the surface of its main body is made of an amorphous carbon and that its bottom part is fitted with electrifying electrodes and has therebetween a heating area to be heated by resistance heating due to its electrification. The same shaping mold from its dipping step through the inspecting step of inspecting the shaped article as adhered to the surface of the mold. In the heat-drying step of the method, the shaped article as adhered to the surface of the shaping mold is heated and dried from the inside of the mold with preventing as much as possible formation of pin holes in the shaped article.

Abstract: A mold includes a thin film electric heating employing voltage and current suppressed below values of an allowable voltage and an allowable current. The thin film electric heat includes a thin film electric resistor formed directly on a surface of the mold and is energized to effect heating. The resistor has a surface resistivity r, expressed by r=.rho./t (where .rho. is the volume resistivity of the thin film electric resistor and t is the film thickness of the thin film electric resistor), within a range to achieve the heating function of the thin film electric heater while the values of voltage and current applied to the thin film electric heater are suppressed below the values of the allowable voltage and the allowable current.

Abstract: A device for melting matter by immersion in a heated vat which includes a basket articulated with respect to a base containing the vat. The basket is resiliently urged upwardly from the vat as a lid covering the basket is raised and members are provided for retaining the basket in its raised position, wherein the basket obstructs access to the vat.

Abstract: A containment structure and a method for making such structure requires the implementation of a plurality of a minimum of building elements. A plurality of panels are interconnected by connector columns in stacked relationship to generate a dual walled shell, adapted to receive concrete between the inner and outer walls thereof. Rebar and other appropriate reinforcing material may be appropriately positioned before the concrete is poured. Additionally, before pouring of the concrete, the mating connections of the panels and column connectors are fused together by the passing of electrical current through conductors received within such elements at their points of interconnection. The rising temperature melts the material of which the panels and column connectors are fabricated, causing them to fuse together. In one embodiment of the invention, a foam barrier is provided on either side of the resultant concrete cylinder.

Abstract: A device is provided which is capable of generating a surface that at least partially conforms to the contour of an article. The surface is defined by the ends of a number of threaded members which are supported within a suitable support structure. The threaded members are aligned so as to be substantially parallel to and threadably engaged with each other. As a result, rotation of an individual threaded member will cause that threaded member to be longitudinally moved relative to its adjacent threaded members and the support structure, without displacing an adjacent threaded member. The surface can be readily configured manually or automatically to serve as a die or mold cavity when the entire surface has been generated to conform to the entire contour of the article. Alternatively, the surface can be generated so as to provide a suitable fixture surface for supporting and securing a workpiece during a machining or welding operation.

Abstract: A chase is arranged on a heating plate of a die set. Semiconductor packages are arranged, as products to be heated, in cavities of the chase. A runner is provided in the surface of the chase to feed a molten resin into the cavities. The heating plate has a hole for a rod-like heater and a hole for a temperature monitoring sensor. The rod-like heater is inserted into the heater insertion hole and the sensor is inserted into the sensor insertion hole. The heater has a plurality of mutually independent heat generation areas in its axial direction. The sensor detects temperature at the heat generation areas of the heater. A control section monitors the temperature near the respective heat generation areas of the rod-like heater and sets the temperature at the respective heat generation areas of the rod-like heater to a predetermined level.

Abstract: A source of radio frequency energy is applied to a low thermal inertia heating element with high thermal conductivity, such as a spool, for rapidly heating the heating element to settable predetermined temperature, which temperature is maintained essentially constant. The heating element is detachably attached about the die of a mold for transferring heat to the die to form, mold, weld or extrude thermoplastic material placed within the mold. Thermal chokes restrict heat transfer from the die to the remainder of the mold. One or more heat sinks draws and dissipates heat from the thermal chokes to maintain cool zones of the mold. Following the heating cycle, upon termination of application of radio frequency energy to the spool, cooling may be accelerated by directing a stream of gas upon the heating element.

Abstract: A heated manifold system for use in the distribution of heated plastic resins to the various cavities of injection molds for thermoplastic materials. The manifold main structure consists of modular components of similar cross-section that are nested into each other by employing similar slots cut out at the points of intersection of components. The thermoplastic resin passages are bored longitudinally in each modular components, and transverse bores at each intersection provide resin passages between the longitudinal bores. The system includes heated nozzles which have slots to receive cartridge heaters and heater covers, also spring clips to retain the covers and heaters, which can rotate around the shank of the nozzle to allow easy replacement of the cartridge heaters in the event of failure. Internal sealed liquid-filled channels or highly conductive metal rods are used to equalize the temperature of the nozzle from one extremity to the other.

Abstract: The starting end and the finishing end of a seam extruded onto a sheet of glass, for example a windshield of an automobile, are joined to complete an edge gasket. A separate supplementary mold receives part of the glass containing the ends of the seam, and a compatible polymerizable composition is poured into the mold to complete the gasket.

Abstract: A method for joining together tubular plastic products (1, 2) by heating the joint faces of the plastic products (1, 2) which have been chamfered at least partly in advance, and by passing molten plastic material into the space (4), that is formed between the opposite joint faces. The fixing of the tubular plastic products (1, 2) and the feed of the molten plastic material take place with the aid of a mold tool (5) which is applied onto the space (4), and molten plastic material is passed rapidly into the hollow space between the mold tool, (5) and the joint faces through a feed stub (6) provided in the mold tube.

Abstract: An apparatus for forming extruded pasta shapes. The apparatus is a die plate having a plurality of orifices wherein the die plate is heated, e.g., to a temperature of at least about 130.degree. F. (about 54.degree. C.), and preferably about 160.degree. F. (about 71.degree. C.) A coating is provided on only a portion of the interior surface of each orifice such that heat transfer to the paste is substantially inhibited in a given orifice until the cross section of the orifice has reached its smallest value.

Abstract: A multilayered insulated mold structure is provided. An insulation layer provided on each of the mold cores retains heat at the molding surface, thereby increasing surface quality of the finished part. The insulating layer has a varying density across its thickness so as to have a low density center region and high density surface regions. By having a relatively low denisty, the center region of the insulating layer has a low thermal conductivity. Thus, the insulating layer may be made from the same material as the core and still have an acceptable insulating value. The use of the same material for adjacent layers reduces the potential of delamination of the layers. The multilayered mold is compatible with passive or active heating of the molding surface.

Abstract: A core for producing a molded resin product having a bent hollow portion, including two-forked and multi-forked products used as parts for automobiles, and a process for producing the aforesaid resin product having a bent hollow portion by using said core.

Abstract: A method for forming a 360 degree integral skin handle in a thermoplastic part for use in automotive trim products includes the steps of forming a mold with a partial recess closed by a removable plug and thereafter selectively directing heat from a first source through the mold and from a second source through the plug to form a completely closed, curved, heated tube surface and thereafter casting thermoplastic material against the curved, heated tube surface to fuse and cure a layer of material thereon in the form of a tube skin segment which is releasable from the mold when the plug is removed. Apparatus for practicing the method includes a mold with a recess therein and a plug is supported on the mold for movement into a position for closing the tube surface and into a demolding position for releasing the molded part.

Abstract: An installation for the fabrication of a series of cells constituting a single construction unit such as a dwelling house or a building story includes a fabrication bed which carries members for subdividing a single placement of concrete into serveral distinct slabs each forming part of one cell. These subdividing members are removably fixed on the fabrication bed in various positions according to the intended width of the cells. The subdividing members carry a device for temporarily immobilizing the two prefabricated panels placed on each side, each device being constituted by a post, the lower end of which can be fixed in an adjustable position on the corresponding subdividing member, and by an external shore of adjustable length.

Abstract: A mold, having a mold cavity commensurate with the shaping, forming or welding to be made, includes an RF energized heater in close proximity to the mold cavity for heating plastic tubing placed within the mold cavity to a temperature sufficient to shape, form or weld the plastic tubing. An RF generator, electrically connected to the RF energized heater, monitors the power applied as a function of the temperature of the heater to heat the plastic tubing to a precise temperature. The mold is of thin wall construction with minimal thermal inertia to expedite both heating and cooling. Various configurations of the mold may be made to form tip shaping, forming or welding, butt welds, annular welds and the like to weld single thermoformable elements or join multiple thermoformable elements.

Abstract: An apparatus for practicing a method for forming a 360 degree integral skin handle in a thermoplastic part for use in automotive trim products. The apparatus includes a mold with a recess therein and a plug being supported on the mold for movement into a position for closing the tube surface and into a demolding position for releasing the molded part. A heater device directs heat from a first source through the mold and from a second source through the plug to form a completely closed, curved, heated tube surface on which thermoplastic material is cast against the curved, heated tube surface to fuse and cure a layer of material thereon in the form of a tube skin segment which is releasable from the mold when the plug is removed.

Abstract: Molding apparatus, for example for molding components of polymerized resin without drawing, comprises a mold defined by a mold wall having a first thermal expansion coefficient, and a die including a die wall having a second thermal expansion coefficient greater than the said first coefficient, a molding operation being carried out by inserting the die into the mold at a first temperature, heating the die and the mold to a second temperature higher than the first temperature, and subsequently cooling the die and the mold after a component has been molded. In accordance with the invention, the die wall includes a plurality of separate sectors which are pivotally mounted on a common support member and which are arranged and dimensioned such that, at the second temperature, the radially outer faces of the sectors adjoin one another contiguously to define the molding face of the die wall.

Abstract: A rubber injection press with a stationary clamping table with a mould element and with a carriage with a further mould element, which carriage is movable in a direction towards the clamping table to close a mould formed by the two mould elements, has a heater associated at least with the stationary mould element and provided in the form of a heating panel, which is arranged between it and the clamping table and in which heating elements are arranged. So as to achieve a good heat transfer from the heating elements to the heating panel with, at the same time, the breakdown frequency being reduced and there being a wide range of design possibilities regarding the arrangement of the heating elements, the latter are cast in the heating panel as heating coils. Thus it is possible also to arrange rapid clamping devices in the heating panel.

Abstract: A compact oven for preparing freshly baked cakes, muffins, and breads from a pourable batter or vertically oriented disk-shaped molds. A hinged cover completes the enclosure. Heat is applied to each vertical side of the molds.

Abstract: A press platen, for bonding ends of a conveyor belt, having both heating and cooling means, the heating means being electrical resistance elements positioned in grooves bars, within the platen, which bars also define cooling channels therein.

Abstract: A method of curing green concrete using electric heating elements that are pulsed on and off by a programmable controller that controls a power source wired to an electric power main. A temperature probe may be used to inform the programmable computer of the concrete's temperature.

Abstract: A panel for a concrete forming structure including two siderails and two end rails extending between and connecting the ends of the siderails. A corrugated, aluminum core member is located inside the area formed by the rails and substantially covers the interior space of the panel. An outer structural sheet extends between the two sets of rails and has the core member connected thereto. An inner plywood sheet extends between the two sets of rails and is attached thereto. The core member is also connected to the plywood sheet. Rigid insulating material fills the inner and outer troughs formed by the corrugated member. A tubular connecting member is provided to connect the afore-mentioned panel to an adjacent panel. It has two connecting flanges extending outwardly from one side and bolt receiving slots formed in each of these flanges. The tubular member has aligned holes therein for passage of a tie rod and special projections that form a channel to receive flanges provided on the edges of the panels.

Abstract: A method for manufacturing a plastic foam, wherein a plastic compound with chemical foaming agent is charged in molding cavity which is defined by a pair of upper and lower die cavities and wherein the plastic compound is subject to a dielectric heating, so that the chemical foaming agent decomposes. One of the cavity surfaces is movable to vary the volume of the molding cavity in accordance with the expansion of the plastic compound, so that the movable cavity surface is kept in contact with the plastic compound which expands during heating.

Abstract: Apparatus for molding a thermoplastic tubular product such as a bushing having an internally threaded major diameter portion and an integral truncated minor diameter portion. A mold provided with a mold shell which jointly with a two-part mold core defines a mold cavity having a shape complementary to the shape of the molded bushing. The molded bushing has an internal undercut in the form of a thread in the major diameter portion thereof. The mold core is made as a core pin and an externally threaded sleeve of greater diameter than the core pin circumferentially of a portion of the core pin. Provision is made for moving the mold elements relatively to define the mold cavity and to effectively release the core by axial compression of the molded product while exposed on the mold core to cause it to swell radially outwardly and release the externally threaded core which forms the internal thread on the molded bushing.

Abstract: A unitary mold for making ice sculpture includes: a mold made of elastomer material having an inner cavity concave downwardly for forming a model of an ice sculpture such as an animal, a building or a person or an article; a perforating bar or needle poking through the mold which can be warmed up to slightly melt the ice surrounding the bar or needle for its easy withdrawal from the ice product and forming a through hole of the ice sculpture for decorative, carrying, or water-drainage purposes; and an expansion-releasing element such as a flip-flop member formed as a part of the mold, serving as a buffer for the expansion of the water during its refrigeration process.

Abstract: An injection moulding tool with optimum temperature distribution as the result of an improved tempering duct system is obtained if the tool inserts (10, 11) are each made up of two or more plates, tempering ducts (12, 12', 12") are worked in from the external faces (F1, F2, F3), on which the parts are subsequently joined by the diffusion welding method. An injection moulding tool for VHS reel hubs produced by this method produces moulds for injection moulding with substantially reduced wobble and a reduced cycle time.

Abstract: A unitary integral electrically heated nozzle device for plastic molding or die casting equipment which has a novel casing integral with a heater core, which is insulated to prevent conduction of electricity and loss of thermal transmission to the casing, the electrical insulation being compacted within the casing and around the heater core and the assembly being sealed and swaged into a unitary form, said device being structured to heat the area of a gate or passage for delivery of molten material into a forming cavity. The nozzle device may be shaped, and the nozzle systems include such nozzle devices in the gate channels for delivering molten material to the forming cavity.

Abstract: For manufacturing articles of plastics, rubber or any other material a mold or die assembly comprising a mold or die base assembled from repetitive modular standard elements consisting of substantially "ready to use" interchangeable base plates is provided by the invention.The base plates are prefabricated by high-precision castings or galvanoplastics or any other similar high-precisious non-cutting method of manufacture.At least two of such base plates are, as mold or die plates, provided with a pre-determined number and arrangement of finished to sized, prefabricated cylindrical bores or piercings of any non-circular, mainly polygonal cross-section. Each of said bores or piercings is capable of fittingly receiving an interchangeable mold or die insert carrying the individually designed (negative) mold or die cavity surface for forming the particular article(s) to be manufactured.

Abstract: Webs for reducing bending in board-shaped construction elements when in use have their main direction of load perpendicular to the board plane. The devices have a sandwich of at least one first material layer, one second material layer, and one third material layer. The third material layer lies between the other two material layers and has a substantially higher coefficient of heat expansion than the other two material layers, so as to set up contracting biasing forces in the third material layer. The third material is made of a sheet metal strip. The two other materials are made of thermosetting plastic, which sets at a temperature considerably above the working temperature of the construction element.

Abstract: A molding cavity wall (10) is made in a plurality of parts of a cheap material having a high thermal conductivity, for example a thin metal sheet (10), at least one heating device (11) is applied on the wall in direct thermal exchange relation to the external surface of the wall (10), and a thermal insulator constituted by a foam (12) of highly rigid resin is applied to the wall (10) in uniform pressure transmitting relation to said wall.

Abstract: The invention relates to a process and a device for the production of shaped bodies of plastic material, in particular polyurethane foam, in molds introduced into an inductor.A process of this type comprises the improvement that for the production of shaped bodies of plastic material, in particular of polyurethane foam or of fibers, non-woven fabrics or the like impregnated or wetted with synthetic resins, latex or the like, of the reactive starting materials introduced into the molds, a frequency of 1 to 30 kHz preferably 5 to 12 kHz, is adjusted and that molds are used in which the individual mold parts are mutually electrically insulated in order to prevent a current flow in the mold around the shaped body and that optionally reinforcements or coating pieces of a material optionally identical to the material of the mold are formed on or applied to the outsides of metallic mold walls for the distribution of the current flow.