EP1525933A2 - Process and machine for making metallic alloy parts - Google Patents

Abstract

Assembly for molding metal alloy products has a lower half-mold (2) and an upper half-mold (3). A supply unit (6) pours molten metal into the lower mold. The lower mold has a pair of identical die cavities (21,22), with a linking channel (23) between them, so that they are both filled with a single pouring.

Description

The present invention relates to a method and a machine for the production of alloy components metallic.

In particular, the invention relates to a process of type "direct squeeze casting" in which said components are produced by a casting process of the molten alloy in a mold reproducing the shape of said component and subsequent solidification of the alloy, which resorts to the exercise of a pressure continuous on said mold.

The patent application EP 0 423 447 describes a process and apparatus to control the pressure of the molten metal in a mold.

The end caps for safety shoes, made in aluminum or aluminum alloy, are an example of such components produced by the process of this invention. Other components that we can possibly realize are pan parts, aluminum window frame components, horseshoes, etc.

Such tips must be made in such a way as to withstand a shock test with a force of 200 joules imposed by a known standard.

To achieve such a test, the tip must have characteristics of robustness and homogeneity that does not can be obtained only with a production method very precise of it, in which matter introduced into the mold must be metered accurately.

One of the main problems of the squeeze process "casting" is precisely the dosage of the material to introduce into the mold. Indeed, the Applicant has observed that in methods of known type it is difficult to dose exactly the amount of material necessary to realize a component having the expected characteristics.

A subsequent problem with known methods is the distribution of the material in the mold during pressure process of the punch in the mold itself. Indeed, during the pressure, the material, in the hypothesis of an abundant dosage, would tend to leave the in the event of insufficient dosage, the product component would have defects homogeneity that could lead to failure in the resistance test referred to above.

In the case of the production of tips for safety shoes, a problem of known methods and not least is that of realizing plurality bits all homogeneous with each other. We can not assure such homogeneity as if the above mentioned dosage of material in the mold is carried out accurately.

The Applicant has solved these problems by point a process and a machine for the realization of components made of aluminum or its alloys, in which the dosing phase of the material in the molds is produced simultaneously in at least two fingerprints of the mold, so as to obtain self-leveling. In furthermore, the method according to the present invention performs, during the pressure of the upper punch or half-mold, controlled recovery of at least a part of the molten material that tends to come out of the half-mold under the effect of said pressure, so as to to make a component having a quantity of alloy adequate and properly distributed. The machine includes in addition a compensation and recovery device material that may have flowed in excessive quantities into the lower mold half during the molding phase of the component.

couler une quantité d'alliage métallique en fusion dans un demi-moule inférieur comprenant au moins une paire d'empreintes ayant la même forme, disposées symétriquement l'une par rapport à l'autre et reliées entre elles par un conduit central,

déplacer un demi-moule supérieur en direction dudit demi-moule inférieur,

récupérer une quantité prédéterminée d'alliage métallique en fusion débordant dudit demi-moule inférieur pendant la phase de fermeture du moule,

fermer le demi-moule supérieur sur ledit demi-moule inférieur et mouler le composant,

extraire du moule le composant réalisé.

One aspect of the present invention relates to a method for the production of metal alloy components comprising the following phases:

pouring a quantity of molten metal alloy into a lower half-mold comprising at least one pair of impressions having the same shape, arranged symmetrically with respect to each other and interconnected by a central conduit,

moving an upper half-mold towards said lower half-mold,

recovering a predetermined quantity of molten metal alloy overflowing from said lower half-mold during the mold closing phase,

closing the upper half-mold on said lower half-mold and molding the component,

extract the mold made component.

A further aspect of the present invention relates to a machine for producing by molding metal alloy components comprising a half-mold lower and an upper half-mold that one can mate with each other to form the model of at least one of said metal alloy components and a supply device of the molten alloy in said lower half-mold. Said lower mold half includes a pair of indentations identical to each other and communicating with each other by a central conduit, so that said feeding device fills both footprints in one casting.

sur la figure 1, on illustre schématiquement une machine pour la production de composants en alliage métallique, en particulier pour le moulage d'embouts pour chaussures de sécurité, en position ouverte selon la présente invention ;

sur la figure 2, on illustre schématiquement la machine de la figure 1 dans une position intermédiaire selon la présente invention ;

sur la figure 3, on illustre schématiquement la machine de la figure 1 dans une position fermée selon la présente invention ;

sur les figures 4a et 4b, on illustre schématiquement des détails agrandis de la figure 3, dans la zone de jonction entre le moule supérieur et le moule inférieur ;

sur la figure 5 on illustre un embout réalisé par la machine et le procédé selon la présente invention.

The features and advantages of the method and [the machine] according to the present invention will become clearer and more obvious by the following description, which serves as an example without being limiting, of an embodiment, description which refers to the attached figures in which:

in Figure 1, schematically illustrates a machine for the production of metal alloy components, in particular for the molding of end caps for safety shoes, in the open position according to the present invention;

in Figure 2, schematically illustrates the machine of Figure 1 in an intermediate position according to the present invention;

in Figure 3, schematically illustrates the machine of Figure 1 in a closed position according to the present invention;

Figures 4a and 4b schematically illustrate enlarged details of Figure 3, in the junction area between the upper mold and the lower mold;

FIG. 5 illustrates a tip made by the machine and the method according to the present invention.

If we refer to the figures cited, the machine for producing end caps for safety shoes and similar products made of aluminum, its alloys and light alloys in general, according to the present invention, comprises a lower half-mold 2 and a half-mold 3, which can be associated respectively to a lower press platen 4 and a upper press plate 5.

We can couple the two half-molds one to the other by means of the relative motion between the trays lower and upper press, and preferably thanks to on the descent of the upper press plate, for define a footprint.

In relation to the lower half-mold, we find a feed device for the molten metal including an anthropomorphic arm 6 that dumps the metal melt in the lower half-mold by a conduit of introduction made for that.

Said upper press platen comprises a piston 7 whose lower end is supported by preferably on the upper half-mold. Said piston moves in a substantially vertical direction of way to push the upper half-mold inside of a cavity defined by said lower half-mold, so that, after the introduction of the molten metal, the coupling between the half-mold upper and the lower half-mold.

The lower half-mold according to the present invention consists of at least two fingerprints 21 and 22 arranged symmetrically to each other so as to make at least one pair of tips at each casting of molten material. These two prints communicate between they in a central zone 23 of the mold, so that that the liquid metal spilled by said device in a footprint can also fill the symmetrical imprint passing through this area communication center 23. In this way, the level of in both footprints is found identical and by therefore the amount of material in both imprints is also substantially identical; this "Self-leveling" allows to make both ends in a very similar way for one and the other: it is fundamental since two tips produced simultaneously can equip the same pair of shoes.

The machine according to the present invention comprises in in addition to a device for compensation and recovery of material that may have flowed in excessive quantities into the lower half mold.

In a first embodiment such a device includes a hydraulic circuit for the recovering molten metal comprising a piston of backpressure 81 whose movement is controlled from preferably by an oleodynamic circuit. This circuit oleodynamic is used to maintain pressure constant on the backpressure piston. The circuit oleodynamic comprises a chamber 82 in which is inserted said piston and which is filled with fluid so much below above the piston, which is placed in a intermediate position. The filling of this room is carried out via two conduits 83 and 84 and a feed pump 85. This pump is able to maintain pressure fluid constant in said chamber and therefore constant pressure on said back pressure piston.

This hydraulic circuit for the recovery of metal melt further comprises a recovery conduit 86 connected at one of its ends to said piston 81 and associated at the end opposite a peripheral portion of the lower half mold. From this peripheral part 87 can overflow a quantity of molten metal during the molding operation.

The process for the production of components in metal alloy according to the present invention is as follows.

The first phase (illustrated in particular on the Figure 1) provides for the casting of the molten metal at the interior of the lower mold half using said supply circuit and in particular said arm anthropomorphic 6.

The liquid at least partially fills the two footprints 21 and 22 arranged symmetrically one by relation to each other and the amount of molten metal spilled into a footprint is found substantially identical to the one in the other, since the communication 23 allows the passage between them of the liquid.

The second phase (illustrated in particular on the Figure 2) provides for the closure of the mold by bringing the top press platter in contact with the platter lower press.

The third phase (illustrated in particular on the Figure 3) provides for the descent of the upper half-mold 3 (punch) in the lower mold half 2 (die). During this phase, excess liquid can overflow of the mold under the effect of the pressure of the half-mold superior. According to the present invention this liquid excess is channeled inside the said conduit 86. To obtain a product with suitable characteristics, a calibration of the excess liquid. In particular, it turns out necessary to control the amount of liquid in excess that tends to overflow the half-mold lower and invade the recovery duct. The backpressure piston 81 exerts on the metal in melting or liquid in excess a predetermined pressure able to allow the overflow of a quantity pre-established of that one.

Figures 4a and 4b show how the liquid that overflows the lower half mold, in the direction of the arrow F1, is routed inside the conduit 86. This thrust of the liquid tends to move the piston of backpressure 81 in the direction of the arrow F2. The movement resulting from this pressure however is limited by the fluid pressure inside the chamber 82 which allows the piston a limited movement and therefore only to a pre-established amount of molten metal to overflow the mold. By acting on the oleodynamic circuit can be determined the amount of molten metal that should be overflowed mold.

According to a variant of the present invention [the] compensation device and recovery of the material having been able to flow in excessive quantities into the mold only include a metal recovery pipe melted in excess.

Another variant of the present invention provides that the backpressure piston is arranged in the lower press platter, especially nearby of the central duct 26, so as to fulfill the function additional ejection of the ends of the half-mold lower once finished the molding phase. In such a configuration, in addition to the oleodynamic circuit which controls the thrust of the back pressure piston, provides for the presence of a pre-compressed spring which allows the movement up the piston once the Upper press platen was raised.

Following the molding, the tips produced can undergo subsequent treatment, by a method of solubilization and quenching able to give them a more great robustness.

Another work that can be done on bits relates to the realization on these of holes in pre-established locations in order to decrease the amount of alloy contained in a mouthpiece and for the purpose to ventilate the area of the shoe where the tip is himself. Of course we will not practice holes in areas of the tip that require greater crush resistance.

In addition, the upper half-mold is shaped so that during the introduction of it into the lower mold half, in an intermediate position like that highlighted in Figure 2, the area middle of the upper half-mold is already in contact with the molten metal while the mold is not completely closed. This allows the molten metal to overflow partially from the mold to contribute to the calibration referred to by the backpressure piston or the recovery conduit.

The type of alloy used to produce these tips is a composition that in itself confers characteristics of successfully passing the test of robustness mentioned above.

An alloy that is suitable for making these tips, in addition to containing aluminum, contains 3.5 to 4% copper, silicon in a content of less than 0.1%, magnesium from 0.4 to 0.5%, titanium from 0.15 to 0.20% and about 0.16% iron.

A tip made according to this method and using this alloy has successfully undergone the shock test referred to above.

Claims (13)

A process for producing metal alloy components comprising the steps of: casting a predetermined amount of molten metal alloy in a lower half-mold comprising at least one pair of indentations having the same shape, arranged symmetrically with respect to each other and interconnected by a central conduit, moving an upper half-mold towards said lower half-mold, recovering a predetermined quantity of molten metal alloy overflowing from said lower half-mold during the mold closing phase, closing the upper half-mold on said lower half-mold and molding the component, extract the mold made component. The method of claim 1, wherein said recovery phase comprises the steps of: channeling said predetermined quantity of alloy, exert a pre-established back pressure on said conduit so as to regulate said amount of molten alloy. The method of claim 1, further comprising the steps of: solubilize the molded component, soak the molded component. Tip for a safety shoe, characterized in that it is made of an aluminum alloy comprising from 3.5 to 4% copper, silicon in a content of less than 0.1%, magnesium from 0.4 to 0.5%, titanium of 0.15 to 0.20% and about 0.16% iron. End piece for safety shoe according to claim 4 comprising a plurality of holes through-holes made at pre-established locations tip. Machine for producing by molding of metal alloy components comprising: a lower half-mold and an upper half-mold which can be coupled to each other so as to form the model of at least one of said metal alloy components, a feed device for the molten alloy in said lower half-mold, characterized in that
said lower half-mold comprises at least one pair of identically identical impressions communicating with each other through a central duct, so that said supply device fills the two cavities in a single casting. Machine for producing by molding of metal alloy components comprising: a lower half-mold and an upper half-mold which can be coupled to each other so as to form the model of at least one of said metal alloy components, a feed device for the molten alloy in said lower half-mold, characterized in that it further comprises a device for compensation and recovery of the material which may have flowed in excessive quantity in the lower half-mold during the molding phase of the component. Machine according to claim 7, wherein said lower half-mold comprises at least one pair fingerprints identical to each other and communicating one with the other by a central duct, so that said feeder fills both footprints in one casting. Machine according to claim 7, wherein said compensation device includes a circuit hydraulic system comprising a back pressure piston and a recovery conduit, connected to one of its ends piston and associated with the opposite end to a peripheral portion of said lower half-mold. Machine according to claim 7, wherein the movement of said piston is controlled by a circuit oleodynamic. Machine according to claim 10, wherein said oleodynamic circuit comprises a chamber in which is inserted said piston and which is filled with a fluid both below and above the piston by through a pair of feed ducts and of a feed pump, said piston being placed in an intermediate position and this pump being capable to maintain a constant pressure of the fluid in said chamber and a constant pressure on said piston. Machine according to claim 8, wherein said backpressure piston is arranged in the tray of lower press, near the central duct, and has a pre-compressed spring that allows movement up the piston once the press platter superior was raised, so as to fulfill the function ejection of the tips of the lower half-mold once completed the molding phase. Machine according to claim 7, wherein said compensation and recovery device includes a recovery duct of the molten metal in excess.

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