MX2007008956A

MX2007008956A - Method and mould for a stratified molding action with metalostatic pressure compensation.

Info

Publication number: MX2007008956A
Application number: MX2007008956A
Authority: MX
Inventors: Enrique Alvarado Murillo
Original assignee: Enrique Alvarado Murillo
Priority date: 2007-07-25
Filing date: 2007-07-25
Publication date: 2007-09-07
Also published as: US20100193151A1; BRPI0721865A2; WO2009014412A1; EP2191912A1

Abstract

Described is a stratified molding mold with metalostatic pressure compensation, which includes one or two staking moulds formed by a generally double frustum rhomboid-shaped cast cavity and one or a plurality of moulding cavities connected to the cast cavity by one or a plurality of supplying ducts, thus each cast cavity pertaining to each staking mold is interconnected to each other so as to form a filling central collector; each cast cavity allows the metalostatic pressure of the melted metal to be compensated during the pouring thereof into the filling central collector in order to obtain a uniform fill of the moulding cavities pertaining to the stacking moulds. The generally double frustum rhomboid-shaped allows temperature to be distributed trough out the mold during the melted metal pour.

Description

METHOD AND MOLD FOR STRATIFIED MOLDING WITH METALOSTATIC PRESSURE COMPENSATION TECHNICAL FIELD OF THE INVENTION This invention relates to the molding of molten metal, and in particular, it relates to a method and mold for stratified molding of multiple pieces by means of stackable molds that feature a pouring cavity in a generally double-rhomboidal shape of COPO that allows to compensate the metallostatic pressure and achieve a temperature distribution in the mold during the casting of the molten metal.

BACKGROUND OF THE INVENTION Currently, the normal mode for simultaneous casting in a plurality of stackable sand molds and the like to empty a plurality of identical or similar pieces, the stackable molds are placed one on top of the other (in what is known as layered molding or stacked molding), and they are arranged so that the sprue or central filling manifold joining together the stackable molds is vertical and, therefore, the molding cavities of each stackable mold are one above the other. By pouring the molten metal into an inlet opening in the upper stackable mold or in the central filling manifold, the mold cavities of the lower stackable molds are first filled and the upper wells are filled later, but the control is minimal with respect to the way in which the molten metal fills each molding cavity.

The inevitable turbulence introduced into the molten metal stream that descends through the central filling manifold and enters a molding cavity practically at a right angle to the direction of the molten metal flow in the central filling manifold, has resulted in the production of parts of poor quality. Likewise, since the stackable molds are vertically arranged, the molten metal, when being drained, induces a high static pressure (known as metallostatic pressure) on the lower stackable molds, which often exerts the effect of the molten metal passing through the metal of stackable molds (known as internal melting), which can lead to the formation of voids during the solidification of the molten metal and to a complete breakage of the mold wall and therefore can cause leaks in the joints between adjacent molds causing the formation of burr or the broken rupture of a joint. Another disadvantage is that since the central collector of generally straight filling promotes an inadequate distribution of temperature along the mold during the casting of the molten metal, it does not allow the formation of hot spots along the mold.

Given the complex structure of the pieces to be molded and the lack of control of the metallostatic pressure during the stratified molding, the use of feeders with enough excess metal is common to allow the location of the plug that forms at the end of the solidification period of the piece, allowing to get healthy pieces.

A current solution to avoid the formation of recesses in the stratified molding is described by José López Almendros, in the European patent EP-0640418, in which a mold for stratified molding is shown where each of its stackable molds includes an appendix in its end corresponding to the molding cavity for control of a gap that is arranged inside the piece, in an area far from the external surface thereof, so that the total filling of the molding cavity is performed without the use of risers.

In view of the above, and the current need to reduce the price of the pieces, together with obtaining a high quality in them, it has become necessary in the industry to offer a method and a mold for stratified molding that through the control of the metallostatic pressure and an adequate distribution of temperature in the mold during the casting of the molten metal allows to achieve an optimum use of the metal used in the casting, which results in a high coefficient of use of said mass of metal and that allows simultaneously Obtaining a greater number of pieces with high quality for a given space of stackable molds, in order to achieve greater productivity.

SUMMARY OF THE INVENTION In view of the previously described and with the purpose of solving the limitations found. It is an object of the invention to provide a mold for layered molding with metallostatic pressure compensation formed by one or more stackable molds formed by a casting cavity in generally rhomboidal form of double truncated cone and one or more molding cavities connected to the cavity of cast by one or more feed lines; such that each pouring cavity of each stackable mold is interconnected to form a central filling collector, and each pouring cavity allows compensating the metallostatic pressure of the molten metal during its emptying by the central filling collector to achieve a generally uniform filling of each of the molding cavities of each of the stackable molds.

It is also an object of the invention to provide a stackable mold including a casting cavity in generally rhomboidal double-frustoconical shape and one or more molding cavities connected to said casting cavity by one or more feed ducts; such that the pouring cavity allows compensating the metallostatic pressure of the molten metal during its casting to achieve a generally uniform filling of each of the mold cavities.

Finally e. Another object of the invention is to provide a method for layered molding with metallostatic pressure compensation, the method includes the steps of: (a) forming a mold for layered molding from a plurality of stackable molds arranged one above the other on a vertical column, each Stackable mold includes a pouring cavity in generally rhomboidal form with double truncated cone; and one or more molding cavities connected to the casting cavity by one or more feed ducts; wherein the stackable molds are arranged so that their respective pouring cavities are placed one on top of the other to form a central filling collector; and (b) pouring molten metal into the central filling manifold so that the molten metal flows through the pouring cavity and fills the mold cavities from the lower stackable mold to the upper stackable mold; where each casting cavity allows compensating the metallostatic pressure of the molten metal during its casting to achieve a generally uniform filling of each of the mold cavities of each stackable mold.

BRIEF DESCRIPTION OF THE FIGURES The characteristic details of the invention are described in the following paragraphs in conjunction with the figures that accompany it, which are for the purpose of defining the invention but without limiting the scope of it.

Figure 1 illust. to a schematic perspective view of a layered molding mold according to the invention.

Figure 2 illustrates a schematic cross-sectional view through the section plane 2-2 'indicated in Figure 1 of a layered molding mold according to the invention.

Figure 3 illustrates a schematic view in longitudinal section through the plane of section 3-3 'indicated in Figure 1 of a mold for laminating molding according to the invention.

Figure 4 illustrates a schematic detail view in longitudinal section of a pouring cavity embodiment of a stackable mold according to the invention.

DETAILED DESCRIPTION OF THE INVENTION The term "mold for stratified molding", in the context of the present description, means a mold formed by one or more stackable molds arranged one above the other in a vertical column.

The term "stackable mold", in the context of the present description, means each of the mold blocks forming the layered molding mold, which includes the molding cavities, casting cavity and feed ducts.

The term "molding", in the context of the present description, means a part manufacturing process based on pouring molten metals into the molding cavity of a mold, to obtain after solidification and cooling a piece that is reproduction of the molding cavity.

The term "molding cavity", in the context of the present description, means hollow space within a mold that represents the shape of the piece to be molded.

The term "pouring cavity", in the context of the present description, means hollow space within a mold used to distribute and feed the molten metal into the mold cavity through the feed conduit.

The term "feed conduit", in the context of the present disclosure, means passage for the molten metal connecting the pouring cavity with a molding cavity.

The term "metallostatic pressure", in the context of the present description, means the static pressure exerted by the molten metal on the internal walls of the layered molding mold and its stackable molds.

With reference to Figures 1, 2, 3 and 4 there is illustrated a mold for laminating molding according to the invention. The mold for stratified molding 10 is formed by one or more stackable molds 20 which in turn each is formed by a casting cavity 30 and one or more molding cavities 40 connected to each other by one or more feed ducts 50. Each Stackable mold 20 can be a sand mold, a permanent mold, i. a ceramic mold.

The pouring cavity 30 and the molding cavities 40 of each stackable mold 20 are formed from the assembly of an upper mold part 60 with a lower mold part 70 by a generally male-female mechanism.

Each of the pouring cavities 30 have a generally rhomboidal shape of double cone frustum and are vertically interconnected to form a central filling collector 80, by which a flow of molten metal, as it is poured into the The stratified molding mold 10 successively fills the pouring cavities 30 of the stackable molds 20 beginning with those of the lower part until they reach those of the upper part. As the molten metal is filled with each casting cavity 30, the molding cavities 40 connected thereto are filled.

The generally rhomboidal double cone shape of each of the pouring cavities 30 allows compensating the metallostatic pressure of the molten metal during its emptying by the central filling collector 80, whereby a generally uniform filling of each one is achieved. of the mold cavities 40 of each of the stackable molds 20.

The double-cone-shaped rhomboidal shape of each of the pouring cavities 30 is formed from an upper cavity 110 in the upper mold part 60 in the form of a truncated cone with a smaller base and a larger base, and a lower cavity in the lower mold part 70 also in the form of a truncated cone with a smaller base and a larger base, such that the assembly of the upper mold part 60 with the lower mold part 70, to integrate a stackable mold 20, upper cavity 110 and lower cavity 120 are opposite each other and joined by their respective major base. The upper cavity 110 or lower cavity 120 may have Bell shape, pyramid trunk shape, spherical segment form of two bases or combinations of these forms.

During the casting of the molten metal by the central filling collector 80 and as the lower cavity 120 of each stackable mold 20 is filled, the metallostatic pressure decreases as the cross-sectional area of this cavity increases and as the cross-section increases When filling the upper cavity 110 of each stackable mold 20, the metallostatic pressure increases as the cross-sectional area of this cavity decreases. This compensation of the metallostatic pressure of the molten metal through its passage through the pouring cavities 30 makes it possible to fill each of the molding cavities 40 uniformly and without forming contractions, so that the plugs are eliminated without the need for use of sprinklers.

In each pouring cavity 30, the minor base of the upper cavity 110 is smaller than the smaller base of the lower cavity 120; while the greater base of the upper cavity 110 is smaller than the larger base of said lower cavity 2.20. This configuration makes it possible to form a central filling collector 80 that varies (from top to bottom) in a stepped manner in its diameter. This irregular shape of central filling collector 80 allows the formation of hot spots, at the points of attachment of the pouring cavities 30, during the casting of the molten metal and therefore a temperature distribution is achieved in the mold for laminating molding. .

In an alternative embodiment, the layered molding mold 10 includes a pouring cup 90 through which the molten metal is poured and is located in the upper part of the mold 10 and connected to the central filling collector 80 at its upper part.

The emptying cup 90 is defined by a bell-shaped mold cavity, Pyramid trunk shape, spherical segment shape of two bases and combinations of these forms.

In another alternative embodiment, the stratified molding mold 10 includes a flow stabilizer 100 located in the lower part of the mold 10 and connected to the central filling collector 80 in its lower part. The flow stabilizer 100 is defined by a bell-shaped mold cavity, pyramid trunk shape, spherical segment shape of a base, spherical segment shape of two bases and combinations of these shapes.

The shape of the drain cup 90 and the flow stabilizer 100 allows no bubbles to form during the casting of the molten metal, because it counteracts or dampens the turbulence of the flow.

According to Figures 1, 2, 3 and 4 described above, a method for stratified molding with metallostatic pressure compensation is observed, the method starts by forming a layered molding mold 10 from a plurality of stackable molds 20 (described above). ) arranged one above the other in a vertical column. Alternatively, a pouring cup 90 is placed in the upper part of the stratified molding mold 10 and in the lower part a flow stabilizer 1 ©, both connected to the central filling collector 80; to then pour molten metal into the central filling manifold 80 so that the molten metal flows through each pouring cavity 30 and fills the molding cavities 40 from the lower stackable mold 20 to the upper stackable mold 20; in such a way that each casting cavity 30 allows to compensate the metallostatic pressure of the molten metal during its casting to achieve a generally uniform filling of each of the molding cavities. 40 of each stackable mold 20. Likewise, each pouring cavity allows the formation of scratchy spots during the pouring of the molten metal by the central filling collector 80 to achieve a temperature distribution along the layered molding mold 10.

Based on the embodiments described above, it is contemplated that the modifications to the embodiments described, as well as to the alternative embodiments, will be considered obvious to a person skilled in the art of the art under the present description. It is therefore contemplated that the claims encompass said modifications and alternatives that are within the scope of the present invention or its equivalents.

Claims

REVIVAL DICTION EN

1. A mold for stratified molding with metallostatic pressure compensation formed by one or more stackable molds, characterized in that each stackable mold includes: a pouring cavity in generally rhomboidal form of double truncated cone; and one or more molding cavities connected to said casting cavity by one or more feed ducts; where each pouring cavity of each stackable mold is interconnected to form a central filling collector and where each pouring cavity allows compensating the metallostatic pressure of the molten metal during its emptying by said central filling collector to achieve a generally uniform filling of each one of said molding cavities of each of said stackable molds.

2. The stratified molding mold of claim 1, characterized in that each stackable mold is formed by an upper mold part and a lower mold part assembled to define said casting cavity and said molding cavities.

3. The stratified molding mold of claim 1, characterized in that said casting cavity includes: an upper cavity in the form of a truncated cone with a smaller base and a larger base; and a lower cone-shaped cavity with a smaller base and a larger base; wherein said upper cavity and said lower cavity are opposite each other and are joined by their respective major base.

4. The stratified molding mold of claim 3, characterized in that the minor base of said upper cavity is smaller than the minor base of said lower cavity.

5. The stratified molding mold of claim 3, characterized in that the major base of said upper cavity is smaller than the larger base of said lower cavity.

6. The mold for laminating molding of claim 3, characterized in that said lower cavity allows lowering the metallostatic pressure during the emptying of the molten metal by said central filling collector to feed the contractions that may be formed in said molding cavities and thus eliminate clogging .

7. The mold for laminating molding of claim 3, characterized in that said upper cavity allows raising the metallostatic pressure during the emptying of the molten metal by said central filling collector to feed the contractions that can be formed in said molding cavities and thus eliminate plugs .

8. The layered molding mold of claim 3, characterized in that said upper cavity has a shape selected from a group comprising a bell shape, a pyramid trunk shape, a spherical segment shape of two bases or combinations of these forms.

9. The layered molding mold of claim 3, characterized in that said lower cavity has a shape selected from a group comprising a bell shape, a pyramid shape, a spherical segment shape of two bases and combinations of these shapes.

10. The mold for stratified molding of claim 1, characterized in that it also includes a drain cup located in the upper part of said mold and connected to said central filling collector.

11. The layered molding mold of claim 10, characterized in that said emptying cup has a shape selected from a group comprising bell-shaped, pyramid-shaped, spherical segment form of two bases and combinations d? - > these forms.

12. The stratified molding mold of claim 1, characterized in that it also includes a flow stabilizer located in the lower part of said mold and connected to said central filling collector.

13. The layered molding mold of claim 12, characterized in that said flow stabilizer has a shape selected from a group comprising a bell-shaped, pyramid-shaped, spherical segment shape of a base, a spherical shape of two spherical segments. bases and combinations of these forms.

14. The stratified molding mold of claim 1, characterized in that each casting cavity also allows the formation of hot spots during the casting the molten metal by said central filling collector to achieve a temperature distribution in said mold.

15. A stackable mold characterized by comprising: a pouring cavity in generally rhomboidal form with double truncated cone; and one or more molding cavities connected to said casting cavity by one or more feed ducts; where said casting cavity allows compensating the metallostatic pressure of the molten metal during its casting to achieve a generally uniform filling of each of said mold cavities.

16. The stackable mold of claim 15, characterized in that it is formed by an upper mold part and a lower mold part assembled to define said casting cavity and said molding cavities.

17. The stackable mold of claim 15, characterized in that in said casting cavity includes: an upper cavity in the form of a truncated cone with a smaller base and a larger base; and a lower cone-shaped cavity with a smaller base and a larger base; wherein said upper cavity and said lower cavity are opposite each other and are joined by their respective major base.

18. The stackable mold of claim 17, characterized in that the minor base of said upper cavity is smaller than the minor base of said lower cavity.

19. The stackable mold of claim 17, characterized in that the larger base of said upper cavity is smaller than the larger base of said lower cavity.

20. The stackable mold of claim 17, characterized in that said lower cavity allows lowering the metallostatic pressure during the casting of the molten metal by said central filling collector to feed the contractions that can be formed in said molding cavities and thus eliminate voids.

21. The stackable mold of claim 17, characterized in that said upper cavity allows increasing the metallostatic pressure during the casting of the molten metal by said central filling collector to feed the contractions that can be formed in said molding cavities and thus eliminate plugs.

22. The stackable mold of claim 17, characterized in that said upper cavity has a shape selected from a group comprising a bell shape, a pyramid trunk shape, a spherical segment shape of two bases and combinations of these forms.

23. The stackable mold of claim 17, characterized in that said lower cavity has a shape selected from a group comprising a bell shape, a pyramid trunk shape, a spherical segment shape of two bases and combinations of these forms.

24. The stackable mold of claim 15, characterized in that further said casting cavity allows the formation of hot spots during the casting of the molten metal to achieve a temperature distribution in said mold.

25. A method for stratified molding with metallostatic pressure compensation, said method is characterized by comprising the steps of: (a) forming a mold for layered molding from a plurality of stackable molds arranged one above the other in vertical column, each stackable mold includes : a pouring cavity in a generally rhomboidal form with a double truncated cone; and one or more molding cavities connected to said casting cavity by one or more feed ducts; wherein the stackable molds are arranged so that their respective pouring cavities are placed one on top of the other to form a central filling collector; and (b) pouring molten metal into said central filling manifold so that the molten metal flows through each casting cavity and fills the mold cavities from the lower stackable mold to the upper stackable mold; where each casting cavity allows compensating the metallostatic pressure of the molten metal during its casting to achieve a generally uniform filling of each of said mold cavities of each stackable mold.

26. The method of claim 25, characterized in that each stackable mold is formed by an upper mold part and a lower mold part assembled to define said casting cavity and said molding cavities.

27. The method of claim 25, characterized in that said casting cavity includes: an upper cavity in the form of a truncated cone with a smaller base and a larger base; and a lower cone-shaped cavity with a smaller base and a larger base; wherein said upper cavity and said lower cavity are opposite each other and are joined by their respective major base.

28. The method of claim 27, characterized in that the minor base of said upper cavity is smaller than the minor base of said lower cavity.

29. The method of claim 27, characterized in that the major base of said upper cavity is smaller than the larger base of said lower cavity.

30. The method of claim 27, characterized in that said lower cavity allows lowering the metallostatic pressure during the emptying of the molten metal by said central filling collector to feed the contractions that can be formed in said molding cavities and thus eliminate plugs.

31. The method of claim 27, characterized in that said upper cavity allows raising the metallostatic pressure during the emptying of the molten metal by said central filling collector to feed the contractions that can be formed in said molding cavities and thus eliminate plugs.

32. The method of claim 27, characterized in that said upper cavity has a shape selected from a group comprising a bell shape, a pyramid trunk shape, a spherical segment shape of two bases or combinations of these forms.

33. The method of claim 27, characterized in that said lower cavity has a shape selected from a group comprising bell shape, pyramid trunk shape, spherical segment shape of two bases and combinations of these forms.

34. The method of claim 25, characterized in that said step of forming a mold for stratified molding from a plurality of stackable molds includes the steps of: placing a pour cup on top of said mold for laminating and connected to said mold central filling collector; and placing a flow stabilizer in the lower part of said stratified molding mold and connected to said central filling manifold.

35. The method of claim 34, characterized in that said emptying cup has a shape selected from a group comprising a bell shape, a pyramid trunk shape, a spherical segment shape of two bases and combinations of these forms.

36. The method of claim 34, characterized in that said flow stabilizer has a shape selected from a group comprising a bell shape, of pyramid trunk, spherical segment shape of a base, spherical segment shape of two bases and combinations of these forms.

37. The method of claim 25, characterized in that each casting cavity also allows the formation of hot spots during the casting of the molten metal by said central filling collector to achieve a temperature distribution in said mold.