EP1099499A1 - 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 one or more inserts in the room, during the molding operation. More particularly, this invention has for subject a process for supplying molten metal or alloy, for molding of such a part with insert.

The light alloy foundry consists in producing pieces of precise dimension, from a metallic material which is first put in fusion, then introduced into a metal mold inside which it solidifies, taking the form imposed by the mold cavity. The form solid thus obtained is extracted from the mold, and the following operation consists by separating 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 molding involves complex hydraulic and thermal phenomena, and it is the technical mastery of these phenomena which allows obtaining parts meeting the requirements set in terms of: "health" of the material, mechanical characteristics, and specific requests.

However, when filling the mold, obstacles interiors such as pins, cores or inserts are all factors that disrupt 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 present defects, not compatible with quality requirements imposed.

In the particular case of a molded part 1 with insert 2, as illustrated in Figure 1 of the accompanying schematic drawing, insert 2 can constitute a more or less significant 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 impeded being indicated in 3. This generates defects in part 1, in the zones 4 opposite to the mold supply, indicated in 5. Such defects may not be acceptable, particularly in the case of a room 1 having a safety function, for example in the automotive field.

The object of the present invention is therefore to reduce, or even remove these drawbacks, due to the presence of an insert, and allow thus obtaining parts with insert by eliminating the negative effects of presence of the insert on the flow of the material during filling of the mold.

To this end, the invention relates to a supply method for molding a part with insert, of the type specified in the introduction, which essentially consists, during filling of the mold, in passing the molten material to be molded through the insert and possibly its support through orifices made in the insert and, if necessary, in its support, and creating at least one transverse channel to said insert and able to be traversed by a flow of molten material to be molded.

Preferably, in the case of a hollow-shaped insert, the holes are provided in opposite areas of the insert, so that create, through the insert, a material flow between the side of feeding the mold and the side opposite this feeding. Through example, in the case of a sleeve or ring-shaped insert, two diametrically opposite orifices are formed in this sleeve.

The inventive idea thus consists in making an insert provided orifices, suitably arranged on the insert and suitably oriented when placing the insert in the mold, these orifices (combined possibly with holes in the insert support) allowing 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 part 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.

Thanks to the process which is the subject of the invention, the filling of the mold can be optimized in the case of a part with an insert, with the following advantageous effects being obtained:

• The flow of molten material circulates, as directly as possible, towards the zone of the mold opposite the feed.
• The solidification of this material 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 part to be molded.

In addition, as a direct consequence of the process according to the invention, the orifices made in the insert, and finally filled by the solidified molding material, allow efficient mechanical attachment of the insert on the molded part.

It will be noted that the supply method, object of the invention, promotes mold filling and contributes to the quality of a part molded with insert, avoiding fault areas, 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 process can also be used in the case of a molding by gravity (without pressure).

The conformation and the number of channels created by the orifices insert and possibly its support, can be adapted in depending on the part to be molded, as well as the 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 supply method for molding a part with insert, thus that applications and variants of this process:

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

Figure 2 is a block diagram similar to Figure 1, but relating to the method 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 part with insert, molded by the method 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 process;

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, consisting of raised portions of the fixed mold part 6a and the movable mold part 6b (see Figure 3).

The sleeve-shaped insert 2, shown alone in FIG. 4, is made of a separate metal, and here it has two holes 8 and 9 of oblong shape, arranged in diametrically opposite positions.

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

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

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

After solidification of this material, the mold 6 is opened by distance from its fixed 6a and mobile 6b parts. The portion of matter solidified, corresponding to channel 11, can then be eliminated leaving in place the material occupying the two orifices 8 and 9 of the insert 2, so as 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 previously described. The part 1 is here a pivot wheel, for motor vehicle, made of aluminum and provided with a insert 2 in the form of a sleeve or a ring, of another metal, located in the region of the central hub of this wheel pivot. Figure 6 illustrates the molding process for such a part 1 with insert 2 which, apart from the shapes particular 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 canal formation 11.

Figures 7 and following illustrate some variants of this process, by way of nonlimiting examples. The variants relate to positions and shapes of the orifices of the insert 2, and of the orifice (s) of the support 7 of insert 2, these examples showing various possibilities orientation of molten metal flows inside the mold 6.

According to Figures 7 and 8, the sleeve-shaped insert 2 still has two opposite holes 8 and 9, but these are positioned laterally. As for the support 7 of the insert 2, this comprises two lateral grooves 10a and 10b, in correspondence with the positions of the holes 8 and 9 of insert 2. The two lateral flows of molten material can thus be brought closer to the center of the mold 6, and pass through partially insert 2, to fill more directly zone 4 located at the opposite of food 5.

In the case of FIG. 9, the channel 11 has a "Y" or flared configuration (holes 8 and 9 are uneven), ensuring better distribution of the molten material in zone 4 opposed to feeding 5.

Finally, as shown in Figure 10, in a variant arising from that of FIGS. 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 overall in "V", so as to greatly reduce the obstacle to the flow of the molten material, constituted by the insert 2 and its support 7.

Other configurations remain possible, in particular in depending on the shapes of part 1 and insert 2.

The invention embraces all the variant embodiments and applicable within the scope of the appended claims, whatever are in particular: the nature of the material to be molded, the shape and the material of the insert, the number and distribution of the holes of the insert, and the resulting configuration of the channel (s) transverse to this insert, the or channels can be straight, angled, "Y", cross, etc ... We note also that, in the case of a massive 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 provide one or more holes in a support insert. Furthermore, this process is compatible with all principles of molding and casting, especially 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 contain one or more inserts.

Claims (4)

Method for supplying molten metal or alloy, for molding parts, in particular of metals or light alloys, with placement of one or more inserts in the part, during the molding operation, characterized in that it consists, during filling of the mold (6), in passing the molten material to be molded through the insert (2) and possibly its support (7), by means of these orifices (8, 9, 10) formed in the insert (2) and, if necessary, in its support (7), and creating at least one channel (11) transverse to said insert (2) and capable of being traversed by a flow of molten material to be molded. Method according to claim 1, characterized in that, in the case of an insert (2) of hollowed out shape, the orifices (8, 9) are provided in opposite areas of the insert (2), so as to create, through insert (2), a flow of material between the feed side (5) of the mold (6) and the side (4) opposite this supply (5). Method according to claim 2, characterized in that the insert (2), in the form of a sleeve or a ring, has two orifices (8, 9) formed in diametrically opposite positions, this insert (2) being positioned in the mold (6), on its support (7), so that one of the holes (8) is located opposite the supply (5) of the mold (6), the other orifice (9) then being placed facing the zone (4) opposite the supply (5), while the support (7) of the insert (2) comprises, between the positions taken by the aforesaid orifices (8, 9), a diametrical orifice (10) defining, with the orifices (8, 9) of the insert (2), the channel (11) transverse to the insert (2). Method according to claim 3, characterized in that the diametrical orifice (10) of the support (7) of the insert (2) results from two grooves complementary formed, respectively, in the fixed parts (6a) and movable (6b) of the mold (6)

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