EP1099499B1 - Molding process feedstock for castings containing an insert - Google Patents

Abstract

A method for the feeding of molten metal or alloy, for the moulding of components notably of light metals or alloys, with one or more inserts placed in the components, during the casting operation is characterised in that it consists, during the filling of the mould (6), of passing the molten material across the insert (2) and possibly its support (7), by means of some orifices (8, 9, 10) cut in the insert (2) and, if necessary, in its support , and creating at least one channel (11) transverse to the insert (2) and able to be travelled through by a flow of the molten material.

Description

The present invention relates to the field of foundry in metal molds, for the production of parts, in particular of metals or light alloys, with placement of one or more inserts in the piece, during the molding operation. More particularly, this invention has for object a process for feeding molten metal or alloy, for molding of such a piece with insert.

The foundry of light alloys consists of producing pieces of precise dimension, from a metallic material that is first put into fusion, then introduced into a metal mold inside which it is solidifies, taking the shape imposed by the cavity of the mold. The form solid thus obtained is extracted from the mold, and the following operation in the separation of the feeding system ("carrot" molding) from the room. The part obtained then undergoes finishing operations and finishing, before assembly or use.

When filling the mold, the flow of the material to casting involves complex hydraulic and thermal phenomena, and it is the technical mastery of these phenomena that makes it possible to obtain parts meeting the requirements in terms of: "health" of the material, mechanical characteristics, and specific demands.

However, when filling the mold, obstacles such as pins, cores or inserts are all factors that disturb the flow of the metal or alloy. Indeed, an obstacle located on the path of the molten metal or alloy causes a division of the flux, creating a "shadow zone" filled in return; at this point, the room can have defects that are not compatible with the quality requirements imposed.

In the particular case of a molded part 1 with insert 2, as illustrated in Figure 1 of the attached schematic drawing, insert 2 can constitute a more or less important obstacle, which must be circumvented by the molten metal or alloy, which thus disrupts the flow of molten material, when filling the mold, the areas where the flow is upset are indicated in 3. This causes defects in part 1, in the areas 4 opposed to the feeding of the mold, indicated in 5. Such defects may not be acceptable, particularly in the case of a coin 1 having a safety function, for example in the automotive field.

The present invention therefore aims to reduce or even to eliminate these disadvantages, due to the presence of an insert, and to allow thus obtaining pieces with insert by eliminating the negative effects of the presence of the insert on the flow of the material during the filling of the mold.

For this purpose, the subject of the invention is a feeding method for the molding of a part with insert, of the type specified in the introduction, which essentially consists, when filling the mold, of passing the molten material to be molded through the insert and possibly its support through openings in the insert and, where appropriate, in its support, and creating at least one transverse channel to said insert and able to be traveled by a stream of melt to mold.

Preferably, in the case of a recess-shaped insert, the openings are provided in opposite areas of the insert, so as to create, through the insert, a flow of material between the side of mold feeding and the opposite side to this feed. By example, in the case of an insert in the form of a sleeve or a ring, two diametrically opposed orifices are formed in this sleeve.

The inventive idea is to create an insert of orifices, suitably arranged on the insert and suitably oriented when placing the insert in the mold, these orifices (combined possibly with orifices formed in the support of the insert) allowing the molten metal or alloy to pass through this insert, to come fill the mold area opposite the feed. Of course, if this is necessary, the solidified material corresponding to the channel passing through the insert can be eliminated during operations carried out after extraction of the solid piece out of the mold.

• Le flux de matière fondue circule, de la manière la plus directe possible, vers la zone du moule opposée à l'alimentation.
• La solidification de cette matière est, elle aussi, dirigée.
• Le ou les canaux créés dans l'insert et/ou dans son support assurent une transmission éventuelle de la pression initiale en tout point de la cavité du moule, correspondant à la pièce à mouler.

With the method of the invention, the filling of the mold can be optimized in the case of a part with insert, with the following advantageous effects:

• The stream of molten material circulates, in the most direct way possible, towards the mold zone opposite the feed.
• The solidification of this matter is also directed.
• The channel or channels created in the insert and / or in its support ensure possible transmission of the initial pressure at any point in the mold cavity, corresponding to the workpiece.

Moreover, as a direct consequence of the process according to the invention, the orifices formed in the insert, and finally filled by the solidified molding material, allow effective mechanical fastening of the insert on the molded part.

It will be noted that the feeding method, object of the invention, promotes mold filling and contributes to the quality of a piece molded with insert, avoiding areas of defects, whatever the principle of the mold and the feeding side of this mold. So the process according to the invention is compatible with molds and injection molding machines with vertical closure and vertical injection, or with horizontal closure and vertical injection, or with horizontal closure and injection horizontal. This method can be used also in the case of a molding by gravity (without pressure).

The conformation and the number of the channels, created by the orifices of the insert and possibly of its support, can be adapted in depending on the part to be molded, as well as desired material flows.

Figure 1 (déjà mentionnée plus haut) illustre, sous forme de schéma de principe, le procédé de moulage traditionnel d'une pièce avec insert ;

Figure 2 est un schéma de principe similaire à figure 1, mais relatif au procédé objet de la présente invention ;

Figure 3 est une vue en coupe suivant III-III de figure 2 ;

Figure 4 est une vue en perspective de l'insert, tel qu'utilisé pour la mise en oeuvre du procédé illustré aux figures 2 et 3 ;

Figure 5 est une vue en perspective d'un exemple concret de pièce avec insert, moulée par le procédé objet de l'invention ;

Figure 6 illustre le procédé de moulage de la pièce de figure 5 ;

Figure 7 est un schéma de principe, similaire à figure 2, illustrant une variante du procédé selon l'invention ;

Figure 8 est une vue en coupe suivant VIII-VIII de figure 7 ;

Figure 9 est un schéma de principe, illustrant une autre variante de ce procédé ;

Figure 10 est un schéma de principe, illustrant encore une autre variante.

In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended schematic drawing illustrating an embodiment of this feed method for molding a part with an insert, as well as that applications and variants of this process:

Figure 1 (already mentioned above) illustrates, in block diagram form, the traditional molding process of a part with insert;

Figure 2 is a block diagram similar to Figure 1, but relating to the method object of the present invention;

Figure 3 is a sectional view along III-III of Figure 2;

Figure 4 is a perspective view of the insert, as used for the implementation of the method illustrated in Figures 2 and 3;

Figure 5 is a perspective view of a concrete example of insert part, molded by the method object of the invention;

Figure 6 illustrates the molding process of the part of Figure 5;

Figure 7 is a block diagram, similar to Figure 2, illustrating a variant of the method according to the invention;

Figure 8 is a sectional view along VIII-VIII of Figure 7;

Figure 9 is a block diagram, illustrating another variant of this method;

Figure 10 is a block diagram, illustrating yet another variant.

Referring first to Figures 2 and 4, we consider the molding of a piece 1 of metal or light alloy, for example aluminum, the part 1 to be produced comprising an insert 2 in the form of a sleeve or Ring. Inside the mold 6, the insert 2 is positioned on a support 7, formed by raised portions of the fixed mold portion 6a and the mobile mold part 6b (see Figure 3).

The insert 2 in the form of a sleeve, shown alone in FIG. 4, is feasible in a separate metal, and here it comprises two orifices 8 and 9 of oblong shape, arranged in diametrically opposed positions.

The insert 2 is positioned in the mold 6, on its support 7, such that one of the orifices 8 is opposite the feed 5 of the mold 6. The other orifice 9 of the insert 2 is then placed facing the zone 4 opposite to the power supply 5.

Between the positions taken by the two orifices 8 and 9, the support 7 of the insert 2 has a diametrical orifice 10, constituted by two grooves complementary parts, respectively, in the mold parts 6a and 6b (see Figure 3). The three orifices 8, 9 and 10, aligned, define a transverse channel 11 to the insert 2, more particularly a diametrical channel, which passes through this insert 2 from one side to the other.

Thus, when filling the mold 6, as indicated by the various arrows in Figure 2, the molten material from feed 5 is subdivided into several streams, more particularly into two lateral flows flowing on either side of the insert 2, and a flow central flowing through the channel 11, so through the insert 2 and its 3. As can easily be understood, this triple flow and in particular the flow through the channel 11 favor the filling, in matter to be molded, Zone 4 opposite to food 5.

After solidification of this material, the mold 6 is opened by away from its fixed parts 6a and mobile 6b. The portion of matter solidified, corresponding to channel 11, can then be removed leaving in place the material occupying the two orifices 8 and 9 of the insert 2, in order to ensure mechanical attachment of this insert 2 to the remainder from room 1.

Figures 5 and 6 illustrate a concrete example of part 1 achievable by the method described above. Piece 1 is here a pivot wheel, for a motor vehicle, made of aluminum and provided with a insert 2 in the form of a sleeve or a ring, made of another metal, located in the region of the central hub of this wheel pivot. Figure 6 illustrates the molding process of such a part 1 with insert 2 which, except for the forms particulars of part 1, is carried out exactly according to the principle previously described, thanks to the two orifices 8 and 9 of the insert 2 and to the formation of the canal 11.

Figures 7 and following illustrate some variants of this method, by way of non-limiting examples. The variants concern positions and shapes of the orifices of the insert 2, and of the orifices of the support 7 of the insert 2, these examples showing various possibilities orientation of molten metal streams inside the mold 6.

According to FIGS. 7 and 8, the insert 2 in the form of a sleeve still has two opposite ports 8 and 9, but these are positioned laterally. As for the support 7 of the insert 2, it comprises two lateral grooves 10a and 10b, in correspondence with the positions of the openings 8 and 9 of the insert 2. The two side flows of molten material can thus be brought closer to the center of the mold 6, and to cross partially insert 2, to fill more directly zone 4 located at the opposite of the power supply 5.

In the case of Figure 9, the channel 11 has a configuration in "Y" or flared (the orifices 8 and 9 being unequal), ensuring a better distributed distribution of the molten material in zone 4 opposed to food 5.

Finally, as shown in Figure 10, in a variant resulting from that of Figures 7 and 8, the orifices 8 and 9 of the insert 2, and the grooves 10a and 10b of the support 7 of the insert 2, have a configuration "V", so as to reduce the obstacle to the flow of the melt constituted by the insert 2 and its support 7.

Other configurations are possible, especially in function of the shapes of part 1 and the insert 2.

The invention embraces all the embodiments and within the scope of the appended claims, whatever in particular: the nature of the material to be molded, the shape and the material of the insert, the number and distribution of the orifices of the insert, and the resulting configuration of the channel or channels transverse to this insert, the or the channels can be straight, cranked, "Y", cross, etc ... It will be noted also, in the case of a solid insert (and not hollowed out), the method of the invention can be implemented by creating a channel only in this insert, without the need to spare one or holes in a support insert. Moreover, this process is compatible with all principles of molding and casting, in particular under pressure or by gravity (without pressure). Finally, it is understood that the method of the invention can apply to molded parts of all sizes, and all destinations, insofar as these parts include one or more inserts.

Claims (4)

1. A method of feeding molten metal or alloy for the casting of parts, particularly parts made of metals or light alloys, with the placement of one or more inserts in the part during the casting operation, characterised in that it consists of causing the molten material to be cast to pass through the insert (2), and possibly through the support (7) thereof, when the mould (6) is filled, by virtue of openings (8, 9, 10) disposed in the insert (2) and in its support (7) if applicable, and creating at least one channel (11) which is transverse to said insert (2) and through which a flow of molten material to be cast can occur.
2. A method according to claim 1, characterised in that, in the case of an insert (2) of hollow form, the openings (8, 9) are disposed in opposite regions of the insert (2) so as to create a flow of material across the insert (2) between the side of the feed (5) to the mould (6) and the side (4) opposite said feed (5).
3. A method according to claim 2, characterised in that the insert (2), which is in the form of a sleeve or ring, comprises two openings (8, 9) disposed in diametrically opposite positions, said insert (2) being positioned on its support (7) in the mould (6) so that one of the openings (8) is situated facing the feed (5) to the mould (6), and the other opening (9) is then situated facing the region (4) opposite the feed (5), whilst the support (7) for the insert (2) comprises, between the positions occupied by the aforementioned openings (8, 9), a diametric opening (10), which, with the openings (8, 9) in the insert (2), defines the channel (11) which is transverse to the insert (2).
4. A method according to claim 3, characterised in the diametric opening (10) in the support (7) for the insert (2) results from two complementary grooves which are disposed in the fixed part (6a) and in the moveable part (6b) of the mould (6), respectively.

Images