EP0091533A1 - Casting equipment for the production of complex-shape metallic pieces by smelting - Google Patents

Casting equipment for the production of complex-shape metallic pieces by smelting Download PDF

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Publication number
EP0091533A1
EP0091533A1 EP82830088A EP82830088A EP0091533A1 EP 0091533 A1 EP0091533 A1 EP 0091533A1 EP 82830088 A EP82830088 A EP 82830088A EP 82830088 A EP82830088 A EP 82830088A EP 0091533 A1 EP0091533 A1 EP 0091533A1
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EP
European Patent Office
Prior art keywords
mould
channels
mold
opening
vacuum
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP82830088A
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German (de)
French (fr)
Inventor
Oddino Dorigo
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Individual
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Individual
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Priority to EP82830088A priority Critical patent/EP0091533A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D25/00—Special casting characterised by the nature of the product
    • B22D25/02—Special casting characterised by the nature of the product by its peculiarity of shape; of works of art
    • B22D25/026—Casting jewelry articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/15—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting by using vacuum

Definitions

  • This process consists in giving a form to the object to be obtained by using a model constructed of material with low melting point.
  • the casting assembly thus obtained is dried until the conglomerate solidifies and is then subjected to a temperature generally close to 200 to 300 ° C., the pouring channel being turned downwards.
  • the molten metal is poured into the pouring channel through a funnel, until the empty space is completely filled.
  • the metal solidifies, it stably takes the geometric shape of the negative imprint, corresponding to the primitive model formed from wax or similar material.
  • the object of the present invention is to intervene by providing an improved casting assembly for producing in a technically updated and satisfactory manner from all angles of forming metal parts of complicated shape by the lost wax process.
  • a casting assembly which comprises a robust and watertight container made of a material resistant to high temperatures, comprising a lower base. upper fitted with a suction opening, a side wall pressed tightly on the base, an upper base pressed tightly on the side wall and provided with an opening for introducing the molten metal which can be closed by a cover capable of sealingly resting on this opening, as well as means which can be associated from the inside with the side wall and the lower base to create, in the mass of the conglomerate forming the mold in the container, several adjacent channels to the side wall and a manifold between the channels and the opening of the lower base adjacent to the latter.
  • Figure 6 is a cross section along the line VI-VI of Figure 1, of the casting assembly of the previous figures.
  • the casting assembly according to the invention comprises a robust container made of material resistant to high temperatures, for example metallic, of substantially cylindrical shape, formed (see for example Figure 4) of a base lower 1, a side wall 2 and an upper base 3.
  • the lower base 1 has in the center a suction opening 4 from which a suction duct 5 leaves and the upper base 3 has in the center an opening d 'introduction of molten metal 6 with pouring funnel 6', which can be closed by a cover 7.
  • the wall 2 is supported on the lower base 1 and the upper base 3 is supported on the side wall 2 by means of respective seals 8 and 9 capable of withstanding high temperatures and capable of guaranteeing a tight seal between the parts.
  • the cover 7 seals the opening 6 with a seal 7 ′.
  • the casting assembly according to the invention forms part of the means which can be associated, inside the container, with the side wall 2 and with the lower base 1 to create, in the mass of conglomerate 10 that it is necessary to introduce into the container to form the mold, several channels 11 adjacent to this wall 2, arranged along the generatrices thereof and a manifold, preferably with radial elements 12, between the bottom of the channels 11 and the opening 4 from base 1.
  • the channels 11 can be obtained by having a cylindrical structure made of metal or plastic comb, suitably treated with suitable lubricants, near the inside of the wall 2, to be extracted before the conglomerate is baked from the mold, or made of cardboard or similar material to be burnt during cooking.
  • the channels 11 can be obtained by placing wooden sticks or straws near the inside of the wall 2 or, advantageously, a sheet of corrugated cardboard, all intended to burn during the cooking of the mold.
  • the bottom collector it is preferable to adopt, for example, a round rubber element with a star structure which can easily be removed before the mold is cooked, but many other solutions will be possible.
  • the casting assembly which has just been described also requires, in order to be handled in service, as will be seen below, additional accessories constituted by closing and retaining jaws 13 indicated in FIG. 3 and capable of maintaining tightly closed the container formed by the various elements 1, 2, 3 when necessary during its handling.
  • the wax model 14 melts and the wax leaves the pouring funnel 6, being collected in a bowl 15. After this operation, the mold is formed since in the cement conglomerate 10, there remains the negative imprint of the object to obtain.
  • the already treated part of the assembly is then placed in an oven so as to obtain at this stage the firing (generally in the vicinity of 800 ° C.) of the cement conglomerate which, owing to its special composition and the loss of l inhibition water is moderately porous so as to allow the passage of air but not that of metal.
  • the metal is melted separately in a crucible 16 and it is then poured into the negative impression through the pouring funnel 6 'and the opening 6 (FIG. 3), until the mold cavity of the casting assembly is completely filled.
  • the pouring channel 6 is closed by means of the cover 7 provided with the seal 10 (FIG. 4).
  • the opening 4 of the lower base 1 was connected to a suction device, represented schematically in FIG. 5 and constituted by a suction pump 17, by a lung with reserve of depression 18 with vacuum gauge 19, by an adjustment valve 20 and by a vacuum gauge 21 bypass on the duct 5.
  • a suction device represented schematically in FIG. 5 and constituted by a suction pump 17, by a lung with reserve of depression 18 with vacuum gauge 19, by an adjustment valve 20 and by a vacuum gauge 21 bypass on the duct 5.
  • the casting assembly is placed in communication with the vacuum lung which performs an air subtraction which the operator can control by means of the vacuum gauge 24 and adjust using tap 20.
  • the arrows in FIG. 5 indicate how the air and possibly other gases trapped by the mold cavity of the casting assembly are removed. As a result of this suction, the metal of the stop 14 adheres more intimately to the walls of the mold 10.
  • peripheral channels 11 created inside the casting envelope, adjacent to the wall 2 of the assembly and leading to. lower manifold 12, allow rapid suction of air and other gases, by the action created by the vacuum system, through the porous cement conglomerate which, allowing the passage of gaseous material, on the other hand prevents the exit of the molten metal, as already mentioned.
  • the seal between the bases 1 and 3 and the wall 2 of the container is simple, effective and long lasting, as is that between the cover 7 and the pouring funnel 6 ', the seal being produced everywhere by means of flat liners 7, 9 and 10 based on asbestos.
  • casting assembly could have other embodiments, different from that which has been described and which fall within the scope of the present invention.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Abstract

Objects of complex shape are cast by the lost wax process in a porous plaster mould. The mould is enclosed in a strong, temp. resistant container, comprising a base with a suction port, a surrounding wall, and a top with a pouring funnel, which can be closed by a pressure tight lid. The units clamp together to form a pressure tight enclosure.S Channels are formed within the mould, against the wall, with connections at the base to the suction port. The port is connected to a suction pump, a vacuum reservoir, a control valve, and vacuum gauges. Vacuum assisted casting using this equipment gives a well filled mould, including undercut recesses, with good detail reproduction. The vacuum reservoir makes the process easy to regulate, and avoids problems of irregularity where direct pumping is employed. The channels in the mould and the connectors to the suction port, are produced when the mould is formed around the wax pattern, either by forms which can be withdrawn and reused, or by disposable shapes which can be burnt out.

Description

On connaît depuis une époque lointaine la fabrication d' objets métalliques par le procédé dit de fusion à "cire perdue".The manufacture of metallic objects by the so-called "lost wax" process has been known for a long time.

Ce procédé consiste à donner une forme à l'objet à obtenir en se servant d'un modèle construit en matériau à bas point de fusion. Traditionnellement, à une certaine époque, on utilisait la cire d'abeilles ; plus récemment, l'industrie chimique moderne a rendu disponibles d'autres produits ayant des caractéristiques similaires et qui fournissent des résultats équivalents, sinon meilleurs.This process consists in giving a form to the object to be obtained by using a model constructed of material with low melting point. Traditionally, at one time, we used beeswax; more recently, the modern chemical industry has made available other products with similar characteristics which provide equivalent, if not better, results.

On introduit le modèle de cire ou matière similaire, correspondant à l'objet, dans un récipient dans lequel on verse ensuite des conglomérats spéciaux de ciment dissous dans de l'eau et ayant une consistance boueuse jusqu'à remplir tout l'espace du récipient laissé libre par le modèle, depuis un canal de coulée relié à cet espace, pour former un moule.We introduce the model of wax or similar material, corresponding to the object, in a container into which we then pour special conglomerates of cement dissolved in water and having a muddy consistency until filling the entire space of the container. left free by the model, from a pouring channel connected to this space, to form a mold.

Ensuite, on sèche l'ensemble de coulée ainsi obtenu jusqu'à solidification du conglomérat et on le soumet par la suite à une température généralement voisine de 200 à 300°C, le canal de coulée étant tourné vers le bas.Then, the casting assembly thus obtained is dried until the conglomerate solidifies and is then subjected to a temperature generally close to 200 to 300 ° C., the pouring channel being turned downwards.

On provoque ainsi la fusion de la cire ou matière similaire et sa sortie par gravité, ce qui a pour effet de créer dans le conglomérat de ciment une cavité de moule c'est-à-dire l'empreinte négative correspondant à l'objet à obtenir.This causes the wax or similar material to melt and exit by gravity, which has the effect of creating a mold cavity in the cement conglomerate, i.e. the negative imprint corresponding to the object to be get.

Ensuite, on verse le métal fondu dans le canal de coulée à travers un entonnoir, jusqu'à remplir totalement l'espace vide. Le métal, en se solidifiant, prend de façon stable la forme géométrique de l'empreinte négative, correspondant au modèle primitif formé de cire ou matière similaire.Then, the molten metal is poured into the pouring channel through a funnel, until the empty space is completely filled. As the metal solidifies, it stably takes the geometric shape of the negative imprint, corresponding to the primitive model formed from wax or similar material.

Ce procédé, utilisé surtout dans le domaine artistique, par exemple par des orfèvres, des argentiers, des fabricants de bijouterie, pour des objets de petites dimensions, présente quelques inconvénients non négligeables quand la forme géométrique de l'objet à obtenir est compliquée, la seule force de gravité n'étant souvent pas suffisante ni pour faire pénétrer le métal fondu dans toutes les zones de l'empreinte, en particulier dans les plus périphériques, les plus resserrées et les moins accessibles, ni pour assurer l'adhérence intime du métal aux parois de l'empreinte négative.This process, used especially in the artistic field, for example by silversmiths, silversmiths, jewelry manufacturers, for objects of small dimensions, has some significant drawbacks when the geometric shape of the object to be obtained is complicated, the the only gravitational force is often not sufficient either to penetrate the molten metal into all areas of the imprint, in particular in the most peripheral, tightest and least accessible, or to ensure the intimate adhesion of the metal at the walls of the negative imprint.

Pour tenter de remédier à ces inconvénients, on a eu recours ces dernières années à divers artifices. Le plus répandu consiste à placer l'ensemble de coulée sur un bras mobile qu'un opérateur fait tourner autour de son axe, généralement à la main, de manière à pousser le métal versé dans le canal de coulée, par force centrifuge, de façon qu'il remplisse efficacement les cavités même les plus éloignées de l'empreinte négative de l'objet à obtenir.In order to try to remedy these drawbacks, various devices have been used in recent years. The most common is to place the casting assembly on a mobile arm that an operator rotates about its axis, generally by hand, so as to push the metal poured into the casting channel, by centrifugal force, so that it effectively fills the cavities even the most distant from the negative impression of the object to be obtained.

Bien que cette mesure indubitablement ingénieuse représente une amélioration relativement à la coulée par seule gravité, elle reste toutefois étroitement liée à l'expérience et à l'habilité de l'opérateur qui doit imprimer à l'ensemble la vitesse de rotation appropriée. Il s'agit donc d'une pratique qui, même si elle fournit des résultats acceptables, s'oppose à la technologie moderne de fabrication qui se base, autant que possible, sur la substitution du contrôle par instruments à l'appréciation sensitive de l'opérateur.Although this undoubtedly ingenious measure represents an improvement relative to casting by gravity alone, it nevertheless remains closely linked to the experience and skill of the operator who must print the appropriate rotational speed as a whole. It is therefore a practice which, even if it provides acceptable results, is opposed to modern manufacturing technology which is based, as much as possible, on the substitution of instrument control for sensitive appreciation of the 'operator.

Selon un autre artifice, au lieu de l'action dynamique exercée par la force centrifuge, on a eu recours à l'action statique exercée par la force de gravité atmosphérique en opérant la soustraction de l'air tout autour de l'ensemble de coulée après avoir convenablement muni de plusieurs trous l' enveloppe de celui-ci. Les ensembles de coulée de ce type qui ont été réalisés.jusqu'à présent et qui tirent parti d'une certaine porosité du conglômérat du moule ont toutefois donné de graves inconvénients étant donné la difficulté de réaliser dans ceux-ci les joints étanches nécessaires pour opérer la soustraction d'air et ils n'ont donc pas satisfait les utilisateurs.According to another device, instead of the dynamic action exerted by the centrifugal force, recourse was had to the static action exerted by the force of atmospheric gravity by operating the subtraction of the air all around the casting assembly. after having suitably provided with several holes the envelope thereof. Casting assemblies of this type which have been produced so far and which take advantage of a certain porosity of the conglomerate of the mold have, however, given serious drawbacks given the difficulty of producing in them the tight seals necessary for operate the air subtraction and they therefore did not satisfy the users.

Dans ce cadre de la technique connue; la présente invention se propose pour but d'intervenir en fournissant un ensemble de coulée perfectionné pour réaliser de façon techniquement actualisée et satisfaisante sous tous les angles de formage de pièces de métal de forme compliquée par le procédé de la cire perdue.In this context of the known technique; the object of the present invention is to intervene by providing an improved casting assembly for producing in a technically updated and satisfactory manner from all angles of forming metal parts of complicated shape by the lost wax process.

L'invention atteint ce but par un ensemble de coulée qui comprend un récipient robuste et étanche en matériau résistant aux hautes températures, comportant une base inférieure munie d'une ouverture d'aspiration, une paroi latérale appuyée de façon étanche sur la base, une base supérieure appuyée de façon étanche sur la paroi latérale et munie d'une ouverture d'introduction du métal fondu pouvant être fermée par un couvercle pouvant s'appuyer de façon étanche sur cette ouverture, ainsi que des moyens pouvant être associés de l'intérieur à la paroi latérale et à la base inférieure pour créer, dans la masse du conglomérat de formation du moule dans le récipient, plusieurs canaux adjacents à la paroi latérale et un collecteur entre les canaux et l'ouverture de la base inférieure adjacente à cette dernière.The invention achieves this object by a casting assembly which comprises a robust and watertight container made of a material resistant to high temperatures, comprising a lower base. upper fitted with a suction opening, a side wall pressed tightly on the base, an upper base pressed tightly on the side wall and provided with an opening for introducing the molten metal which can be closed by a cover capable of sealingly resting on this opening, as well as means which can be associated from the inside with the side wall and the lower base to create, in the mass of the conglomerate forming the mold in the container, several adjacent channels to the side wall and a manifold between the channels and the opening of the lower base adjacent to the latter.

On décrit maintenant l'invention plus en détail en se référant aux dessins annexés qui en illustrent un mode d'exécution pratique et où :

  • les figures 1 à 4 représentent une coupe axiale de l'ensemble de coulée selon l'invention, de façon limitée à certaines de ses parties ou dans son entièreté, aux quatre premières phases du procédé de formage ;
  • la figure 5 représente tout le dispositif des figures 1 à 4, encore en coupe axiale, à la cinquième et dernière phase du même procédé, en association avec un appareil aspirant et
The invention will now be described in more detail with reference to the accompanying drawings which illustrate a practical embodiment thereof and in which:
  • Figures 1 to 4 show an axial section of the casting assembly according to the invention, in a way limited to some of its parts or in its entirety, to the first four phases of the forming process;
  • FIG. 5 represents the entire device of FIGS. 1 to 4, still in axial section, in the fifth and last phase of the same process, in association with a suction device and

la figure 6 est une coupe transversale, suivant la trace VI-VI de la figure 1, de l'ensemble de coulée des figures précédentes.Figure 6 is a cross section along the line VI-VI of Figure 1, of the casting assembly of the previous figures.

Suivant la forme de réalisation donnée et représentée, l'ensemble de coulée selon l'invention comprend un récipient robuste en matériau résistant aux températures élevées, par exemple métallique, de forme pratiquement cylindrique, formé (voir par exemple figure 4) d'une base inférieure 1, d'une paroi latérale 2 et d'une base supérieure 3. La base inférieure 1 comporte au centre une ouverture d'aspiration 4 de laquelle part un conduit d'aspiration 5 et la base supérieure 3 comporte au centre une ouverture d'introduction du métal fondu 6 avec entonnoir de coulée 6', pouvant être fermée par un couvercle 7.According to the embodiment given and shown, the casting assembly according to the invention comprises a robust container made of material resistant to high temperatures, for example metallic, of substantially cylindrical shape, formed (see for example Figure 4) of a base lower 1, a side wall 2 and an upper base 3. The lower base 1 has in the center a suction opening 4 from which a suction duct 5 leaves and the upper base 3 has in the center an opening d 'introduction of molten metal 6 with pouring funnel 6', which can be closed by a cover 7.

La paroi 2 s'appuie sur la base inférieure 1 et la base supérieure 3 s'appuie sur la paroi latérale 2 par l'intermédiaire de garnitures respectives 8 et 9 capables de résister à des températures élevées et propres à garantir un joint étanche entre les parties. De façon similaire, le couvercle 7 ferme de façon étanche l'ouverture 6 grâce à une garniture 7'.The wall 2 is supported on the lower base 1 and the upper base 3 is supported on the side wall 2 by means of respective seals 8 and 9 capable of withstanding high temperatures and capable of guaranteeing a tight seal between the parts. Similarly, the cover 7 seals the opening 6 with a seal 7 ′.

En outre, de l'ensemble de coulée selon l'invention font partie des moyens pouvant être associés, à l'intérieur du récipient, à la paroi latérale 2 et à la base inférieure 1 pour créer, dans la masse de conglomérat 10 qu'il faut introduire dans le récipient pour constituer le moule, plusieurs canaux 11 adjacents à cette paroi 2, disposés suivant les génératrices de celle-ci et un collecteur, de préférence à éléments radiaux 12, entre le fond des canaux 11 et l'ouverture 4 de la base 1.In addition, the casting assembly according to the invention forms part of the means which can be associated, inside the container, with the side wall 2 and with the lower base 1 to create, in the mass of conglomerate 10 that it is necessary to introduce into the container to form the mold, several channels 11 adjacent to this wall 2, arranged along the generatrices thereof and a manifold, preferably with radial elements 12, between the bottom of the channels 11 and the opening 4 from base 1.

Ces moyens ne sont pas représentés puisqu'ils peuvent être des types les plus variés et l'imagination, l'expérience et l'habileté des constructeurs pourront créer facilement des moyens semblabes ou nouveaux. Par exemple, on pourra obtenir les canaux 11 en disposant auprès de l'intérieur de la paroi 2 une structure cylindrique en peigne en métal ou en matière plastique, convenablement traitée par des lubrifiants appropriés, à extraire avant la cuisson du conglomérat du moule, ou en carton ou matière similaire à brûler pendant la cuisson. Ou encore, on pourra obtenir les canaux 11 en disposant auprès de l'intérieur de la paroi 2 des bâtonnets de bois ou des pailles ou encore, avantageusement, une feuille de carton d'emballage ondulé, tous destinés à brûler lors de la cuisson du moule. En ce qui concerne le collecteur de fond, on préfè- rera adopter par exemple un élément rond en caoutchouc à structure en étoile pouvant facilement être enlevé avant la cuisson du moule mais beaucoup d'autres solutions seront possibles.These means are not shown since they can be of the most varied types and the imagination, experience and skill of the builders can easily create similar or new means. For example, the channels 11 can be obtained by having a cylindrical structure made of metal or plastic comb, suitably treated with suitable lubricants, near the inside of the wall 2, to be extracted before the conglomerate is baked from the mold, or made of cardboard or similar material to be burnt during cooking. Alternatively, the channels 11 can be obtained by placing wooden sticks or straws near the inside of the wall 2 or, advantageously, a sheet of corrugated cardboard, all intended to burn during the cooking of the mold. As regards the bottom collector, it is preferable to adopt, for example, a round rubber element with a star structure which can easily be removed before the mold is cooked, but many other solutions will be possible.

L'ensemble de coulée que l'on vient de décrire nécessite en outre pour être manié en service, comme on le verra plus loin, des accessoires supplémentaires constitués par des mâchoires de fermeture et de retenue 13 indiquées sur la figure 3 et capables de maintenir bien fermé le récipient formé par les divers éléments 1, 2, 3 quand il le faut pendant sa manipulation.The casting assembly which has just been described also requires, in order to be handled in service, as will be seen below, additional accessories constituted by closing and retaining jaws 13 indicated in FIG. 3 and capable of maintaining tightly closed the container formed by the various elements 1, 2, 3 when necessary during its handling.

On décrit maintenant l'utilisation de l'ensemble de coulée selon l'invention en se référant aux dessins qui montrent les différentes phases du procédé de formage d'une pièce.The use of the casting assembly according to the invention will now be described with reference to the drawings which show the different phases of the process for forming a part.

On commence par disposer, selon la technologie classique, à l'intérieur de l'ensemble de coulée selon l'invention (figures 1 à 6), le modèle en cire 14 de la pièce à reproduire par formage par coulée. On remplit ensuite l'espace resté vide entre le modèle et le récipient avec un conglomérat approprié de ciment 10 imbibé d'eau et de consistance boueuse, en ayant soin de créer dans la masse du conglomérat 10, auprès de la paroi intérieure 2 du récipient, une série de canaux verticaux 11 reliés au fond, par l'intermédiaire du collecteur 12, à l' ouverture 4 de la base inférieure 1 du récipient.We start by disposing, according to conventional technology, inside the casting assembly according to the invention (Figures 1 to 6), the wax model 14 of the part to be reproduced by forming by casting. Then fill the empty space between the model and the container with an appropriate conglomerate of cement 10 soaked in water and muddy consistency, taking care to create in the mass of the conglomerate 10, near the inner wall 2 of the container , a series of vertical channels 11 connected to the bottom, via the manifold 12, to the opening 4 of the lower base 1 of the container.

Après avoir laissé l'ensemble se passiver et une fois que la solidification du conglomérat 10 est atteinte, on introduit dans un four la partie centrale de cet ensemble (démunie des bases 1 et 3), le canal de coulée tourné vers le bas (figure 2) et on le soumet à l'action de la chaleur (température d'environ 200 à 300°C).After having allowed the assembly to passivate and once the solidification of the conglomerate 10 is reached, the central part of this assembly (deprived of bases 1 and 3) is introduced into an oven, the pouring channel facing downwards (figure 2) and it is subjected to the action of heat (temperature of about 200 to 300 ° C).

Le modèle de cire 14 fond et la cire sort de l'entonnoir de coulée 6, étant recueillie dans une cuvette 15. Après cette opération, le moule est formé étant donné que dans le conglomérat de ciment 10, il reste l'empreinte négative de l'objet à obtenir.The wax model 14 melts and the wax leaves the pouring funnel 6, being collected in a bowl 15. After this operation, the mold is formed since in the cement conglomerate 10, there remains the negative imprint of the object to obtain.

On place ensuite dans un four la partie déjà traitée de l'ensemble de manière à obtenir à ce stade la cuisson (généralement au voisinage de 800°C) du conglomérat de ciment qui, par suite de sa composition spéciale et de la perte de l'eau d'inhibition, est modérément poreux de manière à permettre le passage de l'air mais non celui du métal.The already treated part of the assembly is then placed in an oven so as to obtain at this stage the firing (generally in the vicinity of 800 ° C.) of the cement conglomerate which, owing to its special composition and the loss of l inhibition water is moderately porous so as to allow the passage of air but not that of metal.

On applique maintenant à nouveau les bases 1 et 3 et on en assure la fermeture étanche sur la partie traitée de l'ensemble, au moyen des deux mâchoires 13, puis on renverse à nouveau l'ensemble (figure 3) de façon que l'entonnoir de coulée 6' soit tourné vers le haut.Now apply the bases 1 and 3 again and seal it on the treated part of the assembly, by means of the two jaws 13, then reverse the assembly again (FIG. 3) so that the pouring funnel 6 'is turned upwards.

On effectue séparément dans un creuset 16 la fusion du métal et on le coule ensuite dans lempreinte négative à travers l'entonnoir de coulée 6' et l'ouverture 6 (figure 3), jusqu'à remplissage complet de la cavité de moule de l'ensemble de coulée.The metal is melted separately in a crucible 16 and it is then poured into the negative impression through the pouring funnel 6 'and the opening 6 (FIG. 3), until the mold cavity of the casting assembly is completely filled.

A ce stade, on ferme le canal de coulée 6 au moyen du couvercle 7 muni de la garniture d'étanchéité 10 (figure 4).At this stage, the pouring channel 6 is closed by means of the cover 7 provided with the seal 10 (FIG. 4).

Auparavant, au moyen de la tuyauterie d'aspiration 5, on a relié l'ouverture 4 de la base inférieure 1 à un appareil aspirant, représenté schématiquement sur la figure 5 et constitué par une pompe aspirante 17, par un poumon avec réserve de dépression 18 avec vacuomètre 19, par un robinet de réglage 20 et par un vacuomètre 21 en dérivation sur le conduit 5.Previously, by means of the suction pipe 5, the opening 4 of the lower base 1 was connected to a suction device, represented schematically in FIG. 5 and constituted by a suction pump 17, by a lung with reserve of depression 18 with vacuum gauge 19, by an adjustment valve 20 and by a vacuum gauge 21 bypass on the duct 5.

Si maintenant on met en marche l'appareil aspirant et si l'on ouvre le robinet 20, l'ensemble de coulée est mis en communication avec le poumon de dépression qui effectue une soustraction d'air que l'opérateur peut contrôler au moyen du vacuomètre 24 et régler au moyen du robinet 20.If the suction device is now switched on and the tap 20 is opened, the casting assembly is placed in communication with the vacuum lung which performs an air subtraction which the operator can control by means of the vacuum gauge 24 and adjust using tap 20.

Les flèches de la figure 5 indiquent comment s'effectue la soustraction de l'air et éventuellement d'autres gaz emprisonnés par la cavité de moule de l'ensemble de coulée. Par suite de cette aspiration, le métal de la butée 14 vient adhérer plus intimement aux parois du moule 10.The arrows in FIG. 5 indicate how the air and possibly other gases trapped by the mold cavity of the casting assembly are removed. As a result of this suction, the metal of the stop 14 adheres more intimately to the walls of the mold 10.

Pour les autres opérations et la récupération de l'objet obtenu, on utilise la technique oridinaire de fonderie.For the other operations and the recovery of the object obtained, the standard foundry technique is used.

Il faut se rendre compte que les canaux périphériques 11 créés à l'intérieur de l'enveloppe de coulée, adjacents à la paroi 2 de l'ensemble et menant au. collecteur inférieur 12, permettent d'aspirer rapidement l'air et d'autres gaz, par l'action créée par le système de dépression, à travers le conglomérat poreux de ciment qui, permettant le passage de la matière gazeuse, empêche par contre la sortie du métal à l'état fondu, comme on l'a déjà dit.It should be realized that the peripheral channels 11 created inside the casting envelope, adjacent to the wall 2 of the assembly and leading to. lower manifold 12, allow rapid suction of air and other gases, by the action created by the vacuum system, through the porous cement conglomerate which, allowing the passage of gaseous material, on the other hand prevents the exit of the molten metal, as already mentioned.

Des expériences pratiques répétées ont démontré qu'en général, il convient de disposer, dans l'appareil aspirant, d' une réserve de dépression. L'aspiration directe ne fournit pas en effet de bons résultats étant donné qu'elle cause une absorption irrégulière due à l'action directe de la pompe.Repeated practical experience has shown that, in general, a vacuum reserve should be available in the suction device. Direct suction does indeed not provide good results since it causes irregular absorption due to the direct action of the pump.

En insérant entre la pompe et l'ensemble de coulée un réservoir de capacité appropriée comme le poumon 18, on dispose au contraire d'une réserve de dépression utile pour régler à volonté le flux de soustraction, en obtenant aussi une action de succion qui peut être lente ou rapide selon le degré d'ouverture du robinet 20.By inserting between the pump and the casting assembly a reservoir of suitable capacity such as the lung 18, there is, on the contrary, a useful vacuum reserve for adjust the subtraction flow as desired, also obtaining a suction action which can be slow or rapid depending on the degree of opening of the valve 20.

L'étanchéité entre les bases 1 et 3 et la paroi 2 du récipient est simple, efficace et de longue durée, de même que celle entre le couvercle 7 et l'entonnoir de coulée 6', l'étanchéité étant réalisée partout au moyen de garnitures planes 7, 9 et 10 à base d'amiante.The seal between the bases 1 and 3 and the wall 2 of the container is simple, effective and long lasting, as is that between the cover 7 and the pouring funnel 6 ', the seal being produced everywhere by means of flat liners 7, 9 and 10 based on asbestos.

Il est entendu que l'ensemble de coulée pourrait avoir d'autres modes d'exécution, différents de celui que l'on a décrit et qui rentrent dans le cadre de la présente invention.It is understood that the casting assembly could have other embodiments, different from that which has been described and which fall within the scope of the present invention.

Claims (5)

1. Ensemble de coulée pour le formage de pièces métalliques de forme compliquée par le procédé de fusion "à cire perdue" dans un moule de conglomérat poreux de ciment, caractérisé par le fait qu'il comprend un récipient robuste et étanche en matériau résistant aux hautes températures, comportant une base inférieure munie d'une ouverture d'aspiration, une paroi latérale appuyée de façon étanche sur la base, une base supérieure appuyée de façon étanche sur la paroi latérale et munie d'une ouverture d'introduction du métal fondu pouvant être fermée par un couvercle pouvant s'appuyer de façon étanche sur cette ouverture, ainsi que des moyens pouvant être associés de l'intérieur à la paroi latérale et à la base inférieure pour créer, dans la masse du conglomérat de formation du moule dans le récipient, plusieurs canaux adjacents à la paroi latérale et un collecteur entre les canaux et l'ouverture de la base inférieure adjacente à cette dernière.1. Casting assembly for forming metal parts of complicated shape by the "lost wax" melting process in a porous cement conglomerate mold, characterized in that it comprises a robust and watertight container made of material resistant to high temperatures, comprising a lower base provided with a suction opening, a side wall pressed in a sealed manner on the base, an upper base pressed in a sealed manner on the side wall and provided with an opening for introducing the molten metal which can be closed by a lid which can seally rest on this opening, as well as means which can be associated from the inside with the side wall and with the lower base to create, in the mass of the conglomerate of formation of the mold in the container, several channels adjacent to the side wall and a collector between the channels and the opening of the lower base adjacent to the latter. 2. Ensemble de coulée selon la revendication 1, à l'ouverture d'aspiration de laquelle est relié un appareil aspirant comportant une réserve de dépression.2. A casting assembly according to claim 1, to the suction opening which is connected to a suction device comprising a vacuum reserve. 3. Ensemble de coulée selon la revendication 2, dans lequel l'appareil aspirant comprend une pompe d'aspiration, un poumon de dépression, un robinet de réglage et des vacuomètres de contrôle.3. A casting assembly according to claim 2, wherein the suction device comprises a suction pump, a vacuum lung, an adjustment valve and control vacuum gauges. 4. Ensemble de coulée selon la revendication 1, dans lequel les moyens servant à créer les canaux et le collecteur dans le conglomérat du moule sont seulement associés temporairement à l'ensemble au moment de la formation du moule et sont réutilisables.4. Casting assembly according to claim 1, in which the means serving to create the channels and the collector in the conglomerate of the mold are only temporarily associated with the assembly at the time of the formation of the mold and are reusable. 5. Ensemble de coulée selon la revendication 1, dans lequel les moyens servant à créer les canaux et le collecteur sont perdus et brûlent lors de la cuisson du moule.5. Casting assembly according to claim 1, in which the means used to create the channels and the collector are lost and burn during the baking of the mold.
EP82830088A 1982-04-08 1982-04-08 Casting equipment for the production of complex-shape metallic pieces by smelting Withdrawn EP0091533A1 (en)

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EP82830088A EP0091533A1 (en) 1982-04-08 1982-04-08 Casting equipment for the production of complex-shape metallic pieces by smelting

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EP82830088A EP0091533A1 (en) 1982-04-08 1982-04-08 Casting equipment for the production of complex-shape metallic pieces by smelting

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2160133A (en) * 1984-06-13 1985-12-18 Hitchiner Manufacturing Co Gas permeable metal casting mold having gas collection voids
US4958674A (en) * 1987-03-09 1990-09-25 Schubert & Salzer Maschinenfabrik Aktiengesellschaft Full mold casting process and device
WO1995028244A1 (en) * 1994-04-15 1995-10-26 Hyvaerinen Matti A device for casting precision castings
FR2841489A1 (en) * 2002-07-01 2004-01-02 Jean Gerard Tamaya Jewellery-making procedure uses lost-wax model to apply molten precious metal directly onto volcanic stones

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1135471A (en) * 1954-09-03 1957-04-29 Thomson Houston Comp Francaise Improvements in vacuum foundry
DE2130686A1 (en) * 1970-06-23 1972-02-03 Vestentoft Svend Siig Lost wax casting - using outer vacuum tight steel frame for mould
US3788382A (en) * 1970-11-25 1974-01-29 J Richey Vacuum metal casting apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1135471A (en) * 1954-09-03 1957-04-29 Thomson Houston Comp Francaise Improvements in vacuum foundry
DE2130686A1 (en) * 1970-06-23 1972-02-03 Vestentoft Svend Siig Lost wax casting - using outer vacuum tight steel frame for mould
US3788382A (en) * 1970-11-25 1974-01-29 J Richey Vacuum metal casting apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2160133A (en) * 1984-06-13 1985-12-18 Hitchiner Manufacturing Co Gas permeable metal casting mold having gas collection voids
US4958674A (en) * 1987-03-09 1990-09-25 Schubert & Salzer Maschinenfabrik Aktiengesellschaft Full mold casting process and device
WO1995028244A1 (en) * 1994-04-15 1995-10-26 Hyvaerinen Matti A device for casting precision castings
FR2841489A1 (en) * 2002-07-01 2004-01-02 Jean Gerard Tamaya Jewellery-making procedure uses lost-wax model to apply molten precious metal directly onto volcanic stones

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