EP3695917A1 - Feeder insert, method for producing a feeder body for the feeder insert and king and core box for producing a feeder body box - Google Patents

Abstract

The present invention relates to a feeder insert (1) for use in the casting of metals in a casting mold, comprising a feeder body (2), having - a feeder cavity (3) for receiving liquid metal and - a feeder opening (4) for connecting the Feeder cavity (3) with a mold cavity of the casting mold during the casting process, wherein- the feeder cavity (3) has a larger diameter than the diameter of the feeder opening (4) in at least one portion, - the feeder body (2) consists of an insulating and / or exothermic feeder material, - the feeder body (2) is constructed in one piece, - the feeder opening (4) defines an axis (5), and - the feeder cavity (3) is designed asymmetrically to the axis (5).

Description

The present invention relates to a feeder insert comprising a feeder body for use in casting metals into a casting mold, a method for producing a one-piece feeder body and a king and a core box comprising the king for producing a one-piece feeder body.

In foundry technology, it is often necessary to arrange additional feeder inserts in the casting molds, the feeder body of which fills with the liquid metal when the casting is poured and compensates for any volume deficits that occur during the solidification of the casting, in order to prevent voids in the casting. For this purpose, the feeder inserts must be designed in such a way that the liquid metal fed into them solidifies later than the casting so that material can be transported to the casting during the solidification process, which tightly feeds the casting. For this purpose, the feeder inserts consist of an exothermic and / or insulating material. For this purpose, the feeder inserts have a feeder cavity for receiving liquid metal and a feeder opening for connecting the feeder cavity to a mold cavity of the casting mold during the casting process. In a large number of applications, the feeder insert is during the casting process aligned vertically, ie an axis defined by the feeder opening is aligned vertically. In this case, the feeder cavity adjoining the feeder opening is usually designed to be rotationally symmetrical about the axis, the hydrostatic pressure of the liquid metal located in the feeder cavity being sufficient for replenishment.

However, there are areas of application in which the feeder insert is aligned horizontally with its axis defined by the feeder opening during the casting process. For example, vertical green sand molding systems for the production of casting molds are known (also known as DISA molding systems and DISAMATIC®), in which a first half of the model is mounted on an exclusively linearly adjustable plunger and a second half of the model is mounted on a swiveling mold plate that is between a loading position in which it is aligned horizontally or vertically, for example, and in which it is equipped with a feeder insert, and a particularly vertically aligned casting position is moved back and forth. With these vertically divided casting molds, with which relatively thin-walled castings can be produced and in which the feeder insert is aligned horizontally during the casting process, there is the problem of ensuring the feed. So it's over EP 3 003 601 B1 For example, a two-part feeder body is known whose feeder cavity, delimited by two shaped elements, has a predominant volume above the axis when the axis is arranged horizontally, so that the hydrostatic pressure of the liquid metal located above the axis is sufficient for replenishment. The two molded elements of this feeder insert can be telescoped relative to each other, so that during the production of the casting mold one mold element is shifted to the other mold element, which enables the molding material of the casting mold to be compressed in the area surrounding the feeder opening.

Out DE 87 02 296 a feeder insert is known which, due to the undercut design of the feeder cavity to the feeder opening, consists of two shaped elements which have to be glued to one another after their respective manufacture, which increases the manufacturing costs of the feeder insert. It is therefore desirable to simplify the feeder body of a feeder insert and its manufacture.

For a feeder insert that is vertically aligned during the casting process and has a rotationally symmetrical feeder cavity, it is off WO 2017/046007 A1 known to produce a one-piece feeder body by means of a core shooting machine, in which an expandable, rotationally symmetrical king defines the geometric shape of the feeder cavity during the shooting process.

The object of the present invention is therefore to eliminate the disadvantages described with reference to the prior art and in particular to provide a feeder insert, a method for producing a one-piece feeder body, and a king and a core box having the king for producing the one-piece feeder body, through which the production of a feeder insert arranged horizontally during the casting process is simplified.

The object is achieved by a feeder insert, a method for manufacturing a feeder body and a king and a core box of a core shooting machine with the features of the respective independent claim. Advantageous developments of the invention are specified in the dependent claims and in the description, with individual features of the advantageous developments being able to be combined with one another in a technically meaningful way.

The object is achieved in particular by a king for the production of a feeder body, which is reversibly expandable in its outer contour and extends in a non-expanded state along a central longitudinal axis, the king in an expanded state having an asymmetrical shape with respect to the longitudinal axis.

In the non-expanded state, the king has, in particular, a cross-sectional configuration that can taper conically from a root, which can also be referred to as a foot, of the king to a free end. The cross-sectional design in the non-expanded state of the king can be, for example, circular, oval, elliptical, trapezoidal, rectangular or square, with the corners being rounded in the case of a rectangular or square cross-sectional design. In the case of a rectangular or square cross-sectional configuration, the king thus has two side walls, each at least parallel in cross-section.

According to the invention, it is now provided that the king, in an expanded state, has an asymmetrical shape with respect to the longitudinal axis. The outer contour of the expanded king thus extends in one direction at a greater distance from the longitudinal axis defined in the non-expanded state than in an opposite direction (in a cross-sectional plane orthogonal to the longitudinal axis). The king is designed in particular so that there is little or no expansion in the area of the root of the king, so that the root of the king defines the shape of the feeder opening of the feeder body to be produced.

Such a king is used in particular together with a core box in a core casting machine for the production of a feeder body, wherein the core box comprises at least a first box and a second box. The core box can also comprise further boxes.

• Ausbilden zumindest eines ersten Teilhohlraums in einem ersten Kasten und eines zweiten Teilhohlraumes in einem zweiten Kasten,
• Zusammenbringen zumindest des ersten Kastens und des zweiten Kastens, so dass der erste Teilhohlraum und der zweite Teilhohlraum einen Hohlraum mit einer Innenwandung bilden, wobei die Innenwandung zumindest teilweise die äußere Kontur des herzustellenden Speiserkorpus bildet,
• Einstellen eines reversibel aufweitbaren Königs in den Hohlraum,
• Aufweiten des Königs, so dass der aufgeweitete König zumindest abschnittsweise eine asymmetrische äußere Gestalt aufweist, insbesondere in Bezug auf eine im Ausgangszustand definierte Längsachse des Königs,
• Einbringen von exothermen und/oder isolierenden Speisermaterial zwischen den aufgeweiteten König und die Innenwand des Hohlraums zur Ausbildung des Speiserkorpus, wobei der aufgeweitete König eine Gestalt eines Speiser-Hohlraums vorgibt,
• Zusammenziehen des Königs, bevorzugt nachdem das Speisermaterial ausgehärtet wurde,
• Entfernen des Königs aus dem Speiserkorpus durch Relativbewegung zwischen dem König und dem Speiserkorpus, wobei der zusammengezogene König durch die während des Einbringvorgangs ausgebildete Speiseröffnung, welche im Bereich der nicht aufgeweiteten Wurzel des Königs ausgebildet ist, herausbewegt wird.

Such a core box with a corresponding king can be used to manufacture a one-piece feeder body of a feeder insert, the manufacturing process comprising at least the following steps (if necessary in any order, if technically reasonable):

• Forming at least a first partial cavity in a first box and a second partial cavity in a second box,
• Bringing together at least the first box and the second box so that the first partial cavity and the second partial cavity form a cavity with an inner wall, the inner wall at least partially forming the outer contour of the feeder body to be produced,
• Placing a reversibly expandable king in the cavity,
• Expanding the king so that the expanded king has an asymmetrical outer shape, at least in sections, in particular in relation to a longitudinal axis of the king defined in the initial state,
• Introducing exothermic and / or insulating feeder material between the expanded king and the inner wall of the cavity to form the feeder body, the expanded king specifying the shape of a feeder cavity,
• Contracting the king, preferably after the riser material has hardened,
• Removal of the king from the feeder body by relative movement between the king and the feeder body, the contracted king being moved out through the feeder opening formed during the introduction process, which is formed in the area of the unexpanded root of the king.

Such an asymmetrical outer shape of the expanded king can be achieved, for example, in that the expansion of the king takes place in one direction during manufacture and no expansion takes place in the opposite direction. Of course, there can also be a greater expansion in one direction and a smaller expansion in an opposite direction.

Such an expansion in one direction can be achieved, for example, in that the king has a solid mandrel and comprises a flexible membrane fastened to the mandrel, which membrane can be expanded by introducing a fluid into a space between the membrane and the mandrel, wherein the membrane expands to different degrees when it is expanded in a plane orthogonal to the longitudinal axis of the mandrel. This can take place, for example, in that the membrane has elasticity modules which are arranged locally differently distributed. Alternatively, the expansion in one direction could be caused by a delimitation element which is applied from the outside to the flexible membrane.

However, it is preferred that expansion in one direction and no expansion in the opposite direction is achieved by the membrane with its peripheral edges both in the axial direction (i.e. at the bottom in the area of the root and at the top in the area of the free end of the king) as well as in the circumferential direction (for example along the longitudinal axis on the surface of the fixed mandrel) is attached to the mandrel, for example by vulcanization.

A feeder body produced in this way therefore has a feeder cavity for receiving liquid metal and a feeder opening for connecting the Feeder cavity with a mold cavity of the casting mold during the casting process, the feeder cavity having a larger diameter than the diameter of the feeder opening in at least one portion, the feeder opening defining an axis. The feeder body consists of an insulating and / or exothermic feeder material and is designed in one piece, the feeder cavity being designed asymmetrically to the axis. Such a feeder insert can be produced in just one shooting process in a core shooting machine.

Thus, the feeder cavity thus has a volume which is designed so that with a horizontal arrangement of the feeder insert and the axis defined by the feeder opening, a larger proportion of the volume of the feeder cavity can be positioned above the axis than below the axis. Such a feeder insert is ideally suited for a vertically divided casting mold, in which the feeder insert is arranged horizontally during the casting process, since the liquid metal located above the axis provides sufficient hydrostatic pressure during the casting process, which is necessary for a replenishment of liquid metal in the mold cavity of the mold is sufficient.

The exothermic and / or insulating material of the feeder body is thus homogeneously distributed in the wall area, cover area and the feeder opening having bottom area of the feeder body, so that no interfaces would be formed between individual sections of the feeder body, as would be the case, for example, if the Feeder body would be glued together from several parts. The feeder body can in particular have a further (ventilation) opening on a side opposite the feeder opening (that is to say in the cover area), which is used to guide the cap during molding. Such a further opening can be created, for example, during the manufacturing process of the feeder body, in that the free end of the king opposite the root of the king is not expandable or can be expanded relatively little. The asymmetry of the feeder cavity is characterized in particular by the fact that the feeder cavity extends, starting from the axis defined by the feeder opening, orthogonally to this axis, further than in an opposite direction. The feeder cavity can thus be aligned during the casting process in such a way that a larger feeder volume is arranged above the axis than below.

The feeder cavity preferably has a minimum point on its circumferential surface in the region of the asymmetrical configuration, which is less spaced from the axis than adjacent points on the circumferential surface which are axially adjacent and opposite to the minimum point. Such a minimum point, with which the liquid material initially comes into contact when the feeder cavity is filled, improves the replenishment. Such a point-like or linearly designed minimal point (also known as a Williams notch or Williams strip) can be produced during the manufacture of the feeder body in that the expanded king has a corresponding minimum point on its expanded surface, which is a smaller distance to the longitudinal axis (of the unexpanded king) than in both directions of axially adjacent locations on the expanded surface.

To form the minimum point on the expanded surface of the king, the membrane can be connected to the mandrel on its inside in an expandable area, so that the expansion of the membrane is locally limited. For example, the membrane can be fastened directly and directly to the mandrel at a point or line-shaped point, so that no expansion of the membrane takes place at this fastening point. Alternatively the expansion of the membrane could also be limited with a tether, which is fastened at one end to the mandrel and at the other end to the inside of the membrane.

In a preferred embodiment, the king, in a non-expanded state, has a cross-sectionally rectangular, in particular square, shape with parallel side walls, it being possible for the side walls to be connected to one another by roundings. The side walls can also be designed to be conically tapered along the longitudinal axis. The feeder opening produced in the feeder body would thus also have an essentially rectangular (cross-sectional) shape. In this context it is provided in particular that the membrane is only arranged on one side wall of the king. Alternatively, the king can have a different cross-sectional shape, such as round, oval or elliptical, the membrane preferably only extending over part of the circumference in the circumferential direction. For example, the membrane extends in the circumferential direction over no more than half of the total circumference.

After the feeder body has been manufactured, accessories can be attached to the feeder body, in particular for forming a feeder neck and thus for forming a predetermined breaking point for the metal feeder remainder near the surface of the cast part, for example a so-called ME disk can be attached to the outside of the feeder body in the area of the feeder opening. Alternatively, it would also be possible for the accessories to be arranged in the core boxes in order to be connected to the feeder body produced in the process as soon as the feeder material is injected. The feeder insert then includes in particular the feeder body and the accessories.

Fig. 1:

einen König in Seitenansicht in einem Ausgangszustand,

Fig. 2:

den König in einem aufgeweiteten Zustand,

Fig. 3:

einen aufgeweiteten König mit einem Speiserkorpus und

Fig. 4:

den Speiserkorpus als Bestandteil eines Speisereinsatzes.

The invention and the technical environment are explained below by way of example using the figures. It show schematically

Fig. 1:

a king in side view in an initial state,

Fig. 2:

the king in an expanded state,

Fig. 3:

an expanded king with a feeder body and

Fig. 4:

the feeder body as part of a feeder insert.

Figure 1 shows a king in an unexpanded state. The king 7 comprises a mandrel 9 and a membrane 10. The king 7 extends along a longitudinal axis 8 from a root 14 to a free end 15.

The non-expanded king 7 is rectangular in its cross-sectional configuration, with the membrane 10 extending only over a side wall 13 of the mandrel 9. The membrane 10 is completely attached to the mandrel with its peripheral edge 12. Through lines, not shown, inside the mandrel 9, it is possible to conduct a fluid in an intermediate space 11 between the mandrel 9 and the membrane, so that the membrane 10 and thus the outer contour of the king 7 is widened.

The correspondingly expanded king is in Figure 2 shown. It can be clearly seen that the membrane 10 is only in the in Figure 2 has expanded in the direction shown on the left and not in the opposite, right direction. Accordingly, the king 7 has a shape which is asymmetrical with respect to the longitudinal axis 8. By connecting the membrane 11 to a surface of the mandrel 9, it has also been possible that a minimal point 17 is formed on the outer contour of the widened area, so that the widened area has a camel-like structure.

Such a king 7 is used in a core shooting machine to produce a feeder body 2. Figure 3 shows the use of a similar king 7 with core boxes (not shown) of a core shooting machine. The core boxes each have a partial cavity which, in a merged state, forms a cavity with an inner wall 18, this inner wall defining the outer contour of the feeder body 2 that produces the heart. To produce the feeder body 2, exothermic and / or insulating feeder material is injected between the inner wall 18 of the cavity formed by the core boxes and the outer contour of the expanded king 7. In Figure 3 a correspondingly expanded king 7 is shown with an inserted feeder body 2, the core boxes, which define the outer contour of the feeder body 2, not being shown.

In Figure 4 a feeder insert 1 is shown which comprises the feeder body 2 and an ME disk 16. The feeder body 2 has a feeder cavity 3 and a feeder opening 4, via which the feeder cavity 3 is connected to a mold cavity, not shown, of a casting mold during the casting process. The feeder opening 4 defines an axis 5, whereby it can be clearly seen that the diameter of the feeder cavity 3 is larger than the diameter of the feeder opening 4. Such a feeder insert 1 is used in particular in vertically divided casting molds in which the feeder insert 1 during the Casting process is aligned with its axis horizontally. During the casting process, the feeder insert 1 is therefore.

Since the volume of the feeder cavity 3 is greater above the axis 5 than below the axis 5, a sufficiently high hydrostatic pressure is available through the liquid metal during the casting process to ensure replenishment. The Williams strip 6 formed on the circumferential surface of the feeder cavity 3 serves as a hotspot for the liquid metal.

With the present invention, a feeder body having an asymmetrical feeder cavity can be manufactured in one piece in just one manufacturing process, so that the outlay for manufacturing such a feeder body is significantly simplified.

List of reference symbols

1

Feeder insert

2

Feeder body

3

Riser cavity

4th

Feeder opening

5

axis

6

Williams bar

7th

king

8th

Longitudinal axis

9

mandrel

10

membrane

11

Space

12

Peripheral edge

13

Side wall

14th

root

15th

free end

16

disc

17th

Minimum position

18th

Inner wall

Claims (15)

Feeder insert (1) for use in casting metals in a casting mold, comprising a feeder body (2) - A feeder cavity (3) for receiving liquid metal and - a feeder opening (4) for connecting the feeder cavity (3) to a mold cavity of the casting mold during the casting process, in which - the feeder cavity (3) has a larger diameter than the diameter of the feeder opening (4) in at least one partial area, - the feeder body (2) consists of an insulating and / or exothermic feeder material, - the feeder body (2) is made in one piece, - the feeder opening (4) defines an axis (5), and - The feeder cavity (3) is designed asymmetrically to the axis (5). Feeder insert (1) according to Claim 1, the feeder cavity (3) having a minimum point (6) on its peripheral surface which is less spaced from the axis (5) than axially adjacent points on the peripheral surface in both directions. Feeder insert (1) according to claim 2, wherein the minimal point (6) is point-shaped or linear. Feeder insert (1) according to one of the preceding claims, wherein the feeder opening (4) has a shape which is rectangular in cross section and has parallel feeder opening walls. Feeder insert (1) according to one of the preceding claims, wherein the asymmetry of the feeder cavity (3) extends at most over 150 ° in a sectional plane orthogonal to the axis (5). A method for manufacturing a one-piece feeder body (2) of a feeder insert (1), comprising the following steps: - Forming at least a first partial cavity in a first box and a second partial cavity in a second box, - Bringing at least the first box and the second box together so that the first partial cavity and the second partial cavity form a cavity with an inner wall (18), the inner wall (18) at least partially forming the outer contour of the feeder body (2) to be produced, - Setting a reversibly expandable king (7) in the cavity, - expanding the king (7) so that the expanded king (7) has an asymmetrical outer shape, - Introducing exothermic and / or insulating feeder material between the widened king (7) and the inner wall (18) of the cavity to form the riser body (2), the widened king (7) specifying the shape of a riser cavity (3), - contracting the king (7), - Removal of the king (7) from the feeder body (2) by relative movement between the king (7) and the feeder body (2), wherein the contracted king (7) is moved out through the feeder opening (4) formed during the introduction process. Method according to claim 6, wherein the expansion of the king (7) takes place in one direction and no expansion takes place in the opposite direction. King (7) for producing a feeder body (2), in particular for carrying out the method according to one of Claims 6 or 7, the outer contour of the king (7) being reversibly expandable and, in a non-expanded state, extends along a central longitudinal axis (8 ), characterized in that the king (7) in an expanded state has an asymmetrical outer shape with respect to the longitudinal axis (8). King (7) according to claim 8, wherein the asymmetrically expanded king (7) has a minimum point (17) on its expanded surface, which is less spaced from the longitudinal axis (8) than axially adjacent points in both directions on the expanded surface. King (7) according to claim 8 or 9, wherein the king (7) in a non-expanded state has a cross-sectionally rectangular shape with parallel side walls (13). King (7) according to one of claims 8 to 10, wherein the king (7) has a fixed mandrel (9) and a flexible one attached to the mandrel (9) Membrane (10) which can be expanded by introducing a fluid into an intermediate space (11) between the membrane (10) and the mandrel (9). King (7) according to claim 11, wherein the membrane (10) is attached to the mandrel (9) with its peripheral edges (12) both in the axial direction and in the peripheral direction. King (7) according to Claim 11 or 12, the membrane (10) being connected to the mandrel (9) on its inner side in an expandable area, so that the expansion of the membrane (10) is locally limited. King (7) according to one of Claims 11 to 13, the membrane (10) being arranged only on one side wall (13) of the king (7). Core box for producing a feeder body (2), in particular for carrying out the method according to one of claims 6 or 7, having at least a first box and a second box and a king (7) according to one of claims 8 to 14 that can be inserted into the boxes.

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