US20160346832A1

US20160346832A1 - Method and Device for Making a Casting Mold Having at Least One Lateral Feeder System

Info

Publication number: US20160346832A1
Application number: US15/169,431
Authority: US
Inventors: Joerg Schaefer; Thomas Schaefer
Original assignee: GTP Schaefer Giesstechnishe Produkte GmbH
Current assignee: GTP Schaefer Giesstechnishe Produkte GmbH
Priority date: 2015-06-01
Filing date: 2016-05-31
Publication date: 2016-12-01
Also published as: EP3100801B1; TR201906639T4; DE102015108656B4; DE102015108656A1; EP3100801A1

Abstract

A method for making casting molds includes the steps of providing a casting model (10) that forms a mold cavity of the casting mold, and positioning at least one lateral feeder system (11) at the casting model (10) or mold cavity. The lateral feeder system (11) has a feeder (12) forming an inner feeder cavity (13) and a feeder cage (14) having a connecting channel (15) to the casting model (10) or the mold cavity. A frame (16) made from a heat-resistant material is mounted in the casting mold between an end of the connecting channel (15) on a casting model-side and the casting model (10) or the mold cavity, the frame (16) having a netlike web mounted and fixed therein. The netlike web is made of a fireproof material and has a through-hole.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The instant application claims the priority date of Jun. 1, 2015, the filing date of the German patent application DE 10 2015 108 656.5.

BACKGROUND OF THE INVENTION

The invention relates to a method for making casting molds with a casting model forming the mold cavity of the casting mold and at least one lateral feeding system positioned on the casting model, whereby the lateral feeding system has a feeder forming a feeder cavity and a feeder cage having a connecting channel to the casting model or the mold cavity, and the primary axis of the connecting channel runs at an angle to the primary axis of the feeder, as well as a device for performing the method in the form of a frame comprising a heat-resistant material with a net-like web tensioned therein.
In foundry technology, it is often necessary to provide additional feeders in the casting molds, which fill with the liquid metal during casting of the casting piece and compensate for volume deficits occurring during solidification of the casting piece in order to prevent cavitation shrink holes in the casting piece. Thus, the feeder must be made, such that the liquid metal fed into it solidifies later than the casting piece, so that during the solidification process, a material transport to the casting piece can occur, which seals the casting piece. In this connection, the feeders comprise an exothermic and/or insulating material or are formed as so-called natural sand feeders in the mold sand surrounding the casting model. In the frame of known methods for manufacturing casting molds provided with feeders, the feeders with any geometric shape is arranged at the position to be fed of the later casting piece on the casting model and with the formation of the casting mold by sealing of the mold sand that is introduced are strongly molded or formed. With another method, during forming of the casting model by means of the casting sand, cavities are produced, in which individual feeders made of an exothermic and/or insulating material are later provided and in this manner are connected to the mold cavity formed by the demolding of the casting model. In this manner, the feeders are arranged in the so-called head feeder, which are arranged on the casting model surface or the later casting part, and in the so-called lateral feeders different cavities are positioned, which differ for example based on the inaccessibility from upper feeding points laterally to the casting model or are formed later, and in this regard, have a feeder formed by an inner feeder cavity and a feeder cage having a connecting channel to the casting model, whereby the primary axis of the connecting channel runs at an angle to the primary axis of the feeder. This feeder cage is formed during creation of the casting mold by means of a corresponding model in the mold sand of the casting mold or comprises likewise a specific mold part made from an exothermic and/or insulating material. This type of lateral feeder system is known, for example, from DE 84 18 911.8 U1.
When using feeders, generally the problem exists that after the casting, solidified casting material in the form of so-called feeder residue remains in the feeders, which after demolding of the casting piece must be removed. Since the cleaning costs connected to this process can be substantial, different proposals have been made to form predetermined breaking points in the connection between the feeder and the casting piece in the form of restrictions or edges, where the feeder residue can be broken out of otherwise removed as close as possible to the surface of the casting piece. In particular, lateral feeding systems, however, must provide greater connections to the mold cavity or the later casting piece based on the prevailing thermal conditions, so that for removal of the corresponding feeder residue with lateral feeder systems, often heavy machines such as saws, angle grinders or hydraulic shears must be used.
For producing the desired predetermined breaking points, it is known to mount a web made of a fireproof material in the flow path of the metal flowing curing casting, which, on the one hand, permits the entry of the flowing metal into the feeder cavity or back out into the mold cavity, and on the other hand, based on the washing of the net structure through the hot metal after the solidification of the casting part, forms a metal layer that interfuses with the web and thus produces a defined material weakening, whereby a knocking off of the remaining feeder residue occurs over the web layer. In this regard, with head feeders, it is known to arrange the netlike web to a breaking core mounted on the head feeder.
With lateral feeder systems, generally the netlike webs are anchored between the actual lateral feeder system and the casting model or the mold cavity in the shaped mold sand. This is similar to the use of netlike webs in a running system provided on a finished casting mold for guiding the liquid metal to different casting openings of the casting mold. However, one disadvantage with this method is that the mold sand in the direct vicinity of the casting model has insufficient strength, in order to hold the netlike web with the required tension; thus, the netlike web with the arrangement of the lateral feeder system in the casting mold is provided at a greater distance to the casting model. This results, however, in a greater amount of feeder residue on the casting part, which in turn, requires expensive cleaning processes to resolve.

SUMMARY OF THE INVENTION

The invention therefore is based on the object of providing a method and a suitable device for performing the method, which with the use of lateral feeder systems in the manufacture of casting mold reduces the occurrence of remaining metal residue after casting on the casting piece and which must be removed with cleaning processes.
The invention contemplates a method in which a frame made up of a heat-resistant material with a netlike web tensioned therein is secured between the casting model-side end of the connection channel and the casting model, the net-like web comprising a fireproof material and having a through-hole.
An advantage of the present invention is that, based on the netlike web tensioned in the frame, this frame can be positioned in direct vicinity of the casting model for the mold cavity and is made as a specialized component during the manufacture of the casting mold in a reliably process and commonly with the formation of the lateral feeder system. In so far as a sufficient tensioning of the netlike web in the flow path can be ensured, the web, during the flow through with the liquid metal during the casting process is not pulled into the mold cavity and therewith, into the casting part structure. The arrangement of the frame enables a tensioning and holding of the netlike web in the frame independently of the strength of the mold sand at the positioning point of the netlike web. The use of a frame made from a heat-resistant material for holding the tensioned netlike web offers the advantage that the frame is not melted by the hot metal flowing through the casting mold and therefore, no dangerous combustion gases exists for the casting process.
According to one exemplary embodiment of the invention, according to known method technology, it can be provided that the frame is positioned together with the lateral feeder system on the casting model before formation of the casting mold by molding of the casting model on a model plate supporting the casting model and is formed or molded together with the casting model and the lateral feeder system during formation of the casting mold. Alternatively, during formation of the casting mold by common formation of the casting model with the lateral feeder system position thereon, a recess for later insertion of the frame is formed. In turn, it can alternatively be provided that during formation of the casting mold by molding of the casting model, respectively, a recess for later insertion of the lateral feeder system and frame is formed.
A frame suitable for use with the method of the present invention with a netlike web tensioned herein that is made from a fireproof material and which has a through-hole, according to one embodiment of the present invention, has a conical, tapers shape, whereby the netlike web is secured to the taper side of the frame. In this manner the netlike web, during the positioning of the frame, can be position very close to the casting model contour, while the frame part having broadened side of the frame can be used for fixing the frame in the casting mold.
According to an embodiment of the present invention, it is advantageous if the frame comprises two oppositely moveable partial frames, which can be secured together after the required tensioning of the netlike web is achieved.
With regard to the through-hole formed in the netlike web, it can be provided that this through-hold has a smaller dimension as the cross section of the connecting channel located in the feeder bottom part. According to an embodiment of the invention, it can be provided that the through-hole has a surface of 10 to 50% of the surface of the connecting channel enclosed by the frame, whereby the net width, which means, the width of the net opening is 1 to 22 mm with a width of the fibers forming the net structure of 1 to 15 mm.
According to one embodiment of the invention, the through-hold is arranged centrally in the frame and based on the positioning of the frame, is positioned centrally in the connecting channel of the feeder cage.
According to an embodiment of the invention, the frame can be made of a metallic, ceramic, or a fireproof or heat resistant material.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, an exemplary embodiment of the present invention is provided, which will be described in greater detail below. In the drawings:

FIG. 1 shows the arrangement of a casting model, a frame with a netlike web, and a lateral feeder system in a schematic, exploded view;

FIG. 2 shows a first partial frame of the frame in a detail view;

FIG. 3 shows a second partial frame of the frame in a detail view; and

FIG. 4 shows the frame according to FIG. 1 comprising the first and second partial frames.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows only the schematic arrangement of the parts to be placed into a molding box, which is divided if necessary, for a casting mold to be manufactured, such as a casting model 10, lateral feeder system 11, and frame 16 that holds a netlike web (not shown). The above-noted arrangement is placed onto a pattern plate 19. In the frame of making a casting mold, the above-noted parts are arranged in their technically requirement arrangement to one another either in the molding box and are formed or molded by filling of the molding box or the molding box halves with molding sand, or the casting model is merely formed in the molding box, whereby by means of corresponding additional mold parts, recesses in the mold sand are made, in which subsequently, the frame and the lateral feeder system are disposed.
As shown further in FIG. 1, the lateral storage system 11 comprises a feeder 12 having an inner feeder cavity 13 and a feeder cage 14 having a connecting channel 15, which is arranged with its connecting channel 15 such that a connection between the mold cavity, which exists after removal of the casting model 10 from the molding box (not further shown) and during casting is to be filled with hot metal and the inner feeder cavity 13 of the feeder 12 is provided. In the flow path between the mold cavity and the connecting channel 15 of the feeder cage 14, the frame 16 is arranged with the netlike web held by it in a tensioned manner. The web has a through-hold as a passage for the hot metal flowing through the connecting channel 15 of the feeder cage 14. The frame 16 is arranged, therefore, as close as possible to the casting model 10 or the mold cavity produced thereby, which is supported by the conical, tapered contour of the frame, insofar as the tapered side of the frame 16 is facing the casting model 10 or the mold cavity and the netlike web is secured on the taper side of the frame 16.
Insofar as the frame should comprise a heat-resistant material, the frame can comprise a metal, ceramic, or a flameproof material.
In FIGS. 2 through 4, a frame 16 comprising two partial frames 24, 26 is shown, however, without the netlike web to be held within the frame 16. FIG. 2 shows the first partial frame 24, which forms the outer partial frame of the two-part frame 16. FIG. 3 shows the second partial frame 26, which is identical in construction with the first partial frame 24, but which is dimensioned such that the second partial frame 26 is insertable or displaceable into the first partial frame 24, whereby the netlike web (not shown) is positioned between the two partial frames 24, 26 and is tensioned accordingly.
Each partial frame 24, 26 comprises accordingly frame legs 20 running on three sides and forms a U-shaped design, whereby the open end of the U-shaped arranged frame legs 20 is closed by means of a flat connecting leg 27, so that each partial frame 24, 26 is designed to be stable. The two partial frames each have a conical design, in which the frame legs 20, respectively, are positioned at an angle or slant, such that the lower edge 21 of the frame leg 20 encompasses a smaller surface than the upper edge 22 of the frame leg 20. The surface encompassed by the lower edge of the frame leg 21 is therefore closed by the netlike web plated between the partial frames 24, 26, which means that the netlike web is arranged with the completed frame 16 on the conically tapered side of the frame 16. As far as the first partial frame 24 forms the outer edge region of the frame 16 upon placement of the frame 16, a raised edge 25 extending over the U-shaped frame leg 20 is arranged on the lower edge 21 of the first partial frame 24, which serves to attach and secure the frame 16. On both oppositely disposed frame legs 20 of the two partial frames 24, in addition, three attachment openings 28 are formed, respectively, in the embodiment shown, which enable securing of the frame 16 onto the model structure or in the mold sand. Thus, for example, the mold sane can penetrate the attachment openings 28 and provide a positive locking or form fit between the frame 16 and the mold sane. It also is contemplated to pound a fixing nail through the attachment opening 28, in order to anchor the frame 16 in the mold sand or also to the model structure.
The specification incorporates by reference the disclosure of DE 10 2015 108 656.5, filed Jun. 1, 2015.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.

Claims

We claim:

1. A method for making casting molds, comprising:

providing a casting model (10) that forms a mold cavity of the casting mold;

positioning at least one lateral feeder system (11) at the casting model (10) or mold cavity, wherein the lateral feeder system (11) has a feeder (12) forming an inner feeder cavity (13) and a feeder cage (14) having a connecting channel (15) to the casting model (10) or the mold cavity, wherein a primary axis of the connecting channel (15) runs at an angle to a primary axis of the feeder (12);

mounting a frame (16) made from a heat-resistant material in the casting mold between an end of the connecting channel (15) on a casting model-side and the casting model (10) or the mold cavity, the frame (16) having a net-like web mounted and fixed therein, the netlike web comprising a fireproof material and having a through-hole.

2. The method according to claim 1, further comprising commonly casting the frame (16) with the lateral feeder system (11) before forming the casting mold by molding of the casting model (10) on a model plate (19) supporting the casting model on which the casting model (10) is positioned and upon making of the casting mold commonly with the casting model (10) and the lateral feeder system (11).

3. The method according to claim 1, in which upon making the casting mold by common casting of the casting model (10) with the lateral feeder system (11) positioned thereon, a recess is formed for subsequent insertion of the frame (16).

4. The method according to claim 1, in which upon making of the casting mold by casting of the casting model (10) respective, a recess for subsequent insertion of the lateral feeder system (11) and frame (16) is formed.

5. A frame with a netlike web made of a fireproof material and having a through-hold tensioned therein for performing the method of claim 1, wherein the frame (16) has a conical, tapered contour and wherein the netlike web is fixed to the tapered side of the frame (16).

6. The frame according to claim 5, wherein the frame (16) comprises two partial frames (24, 26) oppositely moveable relative to one another, wherein the two partial frames (24, 26) are attachable to one another after application of a required tensioning of the netlike web.

7. The frame according to claim 5, wherein the through-hold formed in the netlike web has smaller dimensions than a cross section of the connecting channel (15) formed in a feeder lower section (14).

8. The frame according to claim 5, wherein the through-hold is disposed centrally in the frame (16) and based on the positioning of the frame (16), is positioned centrally in the connecting channel (15) of the feeder cage (14).

9. The frame according to claim 5, wherein the frame (16) comprises a metallic material.

10. The frame according to claim 5, wherein the frame (16) comprises a ceramic material.

11. The frame according to claim 5, wherein the frame (16) comprises a fireproof material.