WO2017092845A1

WO2017092845A1 - Method for the production of a casting mold

Info

Publication number: WO2017092845A1
Application number: PCT/EP2016/001917
Authority: WO
Inventors: Stephan Back; Michael HEFTRICH; Markus Bahr
Original assignee: Audi Ag
Priority date: 2015-12-03
Filing date: 2016-11-17
Publication date: 2017-06-08
Also published as: DE102015015629A1

Abstract

The invention relates to a method for manufacturing a casting mold (40) for a motor vehicle component that is to be cast, wherein the casting mold (40) is made from sand in an additive manufacturing process.

Description

Method for producing a casting mold

The invention relates to a method for producing a casting mold, and to a method associated therewith for producing a component from a casting mold.

For the production of a component can be provided to cast this with the aid of a mold. First, the casting mold is to be produced. For this purpose, usually individual components of the component based on design data to provide a model of the component in

Styrofoam milled. Such a model of styrofoam, which can also be referred to as a positive form, is then sent. From the submitted model of Styrofoam creates a negative form or the mold. Subsequently, this mold is poured out to

To obtain components of the component. Here, the sent in model of Styrofoam burned, wherein at least one Kevität ice Negetiv form is filled by liquid metal. The cast component eus Metell is to continue working mechanically. It is also possible that the manufactured component should comprise a cooling system. In this case, this cooling system comprises a plurality of cooling channels, which are drilled in the cast quarry. However, it should be borne in mind that such bores can only be implemented in line production. A curved chiller, which is not lineer shaped, can not be manufactured by drilling.

Publication WO 2015/029935 A1 discloses a method for producing a body eus Send with a 3D Druckverfehren. In the document DE 20 2012 100 640 A1 is an arrangement of

confesses contour-related tempering in a tool. A salt core for making a casting having a layered construction and by means of a generative manufacturing process

is to be prepared, is described in the document DE 10 2014 214 528 A1. Furthermore, the publication DE 10 2004 027 109 A1 discloses a casting method for producing a temperature-controllable tool which has an engraving.

Against this background, procedures with the characteristics of the

independent claims presented. Embodiments of the methods are evident from the dependent claims and the description.

According to the invention, a method is provided for producing a casting mold for a component to be cast for a motor vehicle, wherein the casting mold is produced from sand by a three-dimensional printing process.

The casting mold comprises at least one partial casting mold. In the method, first with a first dispenser on a surface of a

Worktops a loose mass of sand and an activator substance, which are mixed together, applied. Thereafter, a binding substance is applied to the loose mass of sand and the activator substance with a second donor, wherein the mass of sand and the

Activator substance and the added binding substance chemically react with each other, wherein the loose sand is cured to a sand core in areas in which the binding substance is applied.

In the method, for the production of the casting mold from the loose mass, the sand and the activator substance and thus forms a sand activator mixture, at least one by the three-dimensional printing process Part mold to produce at least one sand core made of at least locally hardened sand.

Usually, the at least one partial casting mold is produced from at least one layer. To form the at least one layer, the mass, which comprises sand and the activator substance, is applied to a surface. From the layer which is formed from the loose mass, a layer of a sand core is cured after addition of the binding substance in regions of the at least one partial casting mold to be produced. Loose excess mass of sand and the activator substance is in

Embodiment of and / or removed from the at least one layer formed the sand core.

In an embodiment, the at least one partial casting mold is produced from a plurality of layers. In this case, after producing an n-th layer of a sand core on this n-th layer, the loose mass comprising the sand and the activator substance is applied, wherein u. a. the n-th layer is used as a surface for an η + 1-th layer of a sand core to be produced. The initially loose mass reacts after adding the

Binding substance in areas of the η + 1-th layer to be produced with the binding substance, whereby the sand core is hardened. In addition, excess loose mass of sand and the activator substance and

Tissue removed from the formed η + 1-th layer of the sand core. In an embodiment, loose, excess mass is removed only after completion of a final or final layer, since the loose mass also serves in the unbound state as a support for at least one overlying layer of the sand core. In addition, at least one additional sand core is already out

arranged hardened sand on the at least one layer and / or inserted into the at least one already cured layer. In addition, it is possible that the at least one additional sand core, for example at least one strand of already hardened sand, into the finished, d. H. hardened and cleaned mold is inserted from sand cores. In this case, the at least one additional sand core, eg strand, previously also prepared by curing a loose mass of sand and the activator substance. The sand core, which is also sand-printed, is inserted into the mold and later encased in metal, whereby the sand core forms a channel within the component after removal of the sand. If several sand cores are connected to each other, they are inserted as channels in the mold and surrounded and form a network of channels.

With the mold produced by the method, a negative copy for the component to be produced is provided. Usually, the loose mass of sand and the activator substance is used, which is mixed with the binding substance. The activator substance and the binding substance react with each other to provide a layer of a sand core. In addition, it is possible that the mold is composed of several sub-casting molds and thus provided.

Furthermore, a method for producing a component for a motor vehicle is provided, in which the component is cast from a casting, which is produced by the method described above. Thus, it is possible to print the at least one partial mold for producing the component with a three-dimensional printing process from a mass of sand, wherein the at least one partial mold is produced directly as a negative mold for the component to be cast. Here are the

Construction data of the component to be cast including a

Casting allowance in a model for the at least one part mold

which is produced directly by the three-dimensional printing process.

Thus, among other things, it is possible to dispense with an otherwise usual model of Styrofoam. As a result, harmful vapors that form when burning the model of Styrofoam during casting, avoided. As a result, it is also possible within the scope of the method to reduce the casting allowance, since structural disturbances which arise due to the burning of polystyrene and accumulate on the surface of the casting mold do not occur. Otherwise, such structural defects are to be removed and / or reamed off. With the procedure. it is also possible to print holes and threads on additional sand cores directly into the mold so that they do not drill subsequently and possibly only by fine

Finishing are to be completed. An untreated surface of the at least one partial casting mold which arises during the process has a largely smooth structure. Here, the risk is low, that, for example, in small wells remnants of loose sand are stored, which otherwise at a later

Completion of the component or a tool in a series production can lead to errors and malfunctions. By using the three-dimensional printing process offers a great freedom of design for a user, since in the at least one

Partial mold now undercuts or internal structures can be introduced.

To manufacture the component, the manufactured mold is used like a conventional mold. The at least one additional sand core produced in the process is, for example, also produced by printing and stored in the at least one partial casting mold contoured and running parallel to the contour. If this at least one additional sand core is enclosed in a later casting with metal, the channel formed therefrom runs in the component contour close and contour parallel to the surface and thus provides an optimal

Cooling capacity.

For producing the component, liquid starting material, for example of metal or plastic, is cast, cooled and cured in the produced casting mold. Thereafter, the mold formed from sand is removed again. The at least one cooling channel is thereby produced by removing the sand, which is used to provide the at least one strand. Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained not only in the respectively specified

Combination, but also in other combinations or in isolation are usable without departing from the scope of the present invention.

The invention is schematically illustrated by means of embodiments in the drawings and will be described schematically and in detail with reference to the drawings.

FIG. 1 shows a schematic representation of a sequence of individual steps of an embodiment of the method according to the invention for producing a casting mold.

FIG. 2 shows an example of a component to be produced by the method according to the invention for producing a component. FIGS. 1 a, 1 b, 1 c, 1 d, 1 e, 1 f, 1 g, 1 h, 1 i, 1 j, k, 11, 1 m and 1 n show schematically different successive steps for carrying out the embodiment of the method according to the invention for producing a casting mold , 1 a to 1 h show an arrangement 2 for carrying out a three-dimensional printing process, which has as components a working table 4 designed as a container and a first dispenser 6 and a second dispenser 8. For controlling the method, the arrangement 2 has a computing unit 10. The two dispensers 6, 8 are arranged above the work table 4. When the method is carried out, as indicated by a first double arrow 12, the work table 4 is moved in the vertical direction relative to the dispensers 6, 8 arranged above it. In contrast, the two dispensers 6, 8 are moved relative to the work table 4 (double arrows 14, 16) in the horizontal direction. As part of the process, a loose mass comprising a mixture of sand and an activating substance is provided by the first dispenser 6 and conveyed to the worktable 4. From the second dispenser 8, a binding substance is provided and conveyed to the work table 4. Here, with the first dispenser 6, the loose mass of sand and the activator substance on a surface of the work table 4 surface

applied. In addition, the binding substance is applied by the second dispenser 8 in a respective contour to be produced on the loose mass of sand and the activator substance previously applied over the whole area. Both donors 6, 8 are not shown further storage containers for the loose mass of sand _{J (} and the activator substance and the binding substance assigned.

Figures 1 b and 1 c show how by the first dispenser 6 a first full-surface layer 18.1 of the loose mass of sand and the

Activation substance is applied to a surface of the work table 4, wherein the first dispenser 6 first starting from a

Starting position (Figure 1a) to a first position (Figure 1 b) is moved. By contrast, FIG. 1 c shows the completely applied first layer 18. 1 that is completely on the surface of the first dispenser 6

Worktable 4 is applied. For this purpose, the first dispenser 6 is once completely moved over the work table 4 and then moved back to its original position. Figure 1d shows how the second dispenser 8, starting from its

Starting position (eg., Figure 1c) is moved to a first position relative to the work table 4, wherein from the dispenser 8 to the first layer 18.1 from the loose mass of sand and the activator substance

sections of the binding substance is applied. The loose mass of sand and the activator substance react with the binding substance, wherein the sand is cured and a first layer 20.1 of a hardened sand core is provided.

After applying the first layer 18.1 of the loose mass and after

Providing the first layer 20.1 of the sand core, the work table 4, as indicated with reference to FIG. 1f, moves relative to the two dispensers 6, 8 by one layer height downwards. Thereafter, on the first two layers 18.1, 20.1, first of the first dispenser 6, a second

Layer 18.2 of the loose mass of sand and the activator substance

applied. Thereafter, the binding substance is applied again on this second layer 18.2 from the loose mass of the second dispenser 8, wherein the second layer 18.2 of the loose mass of sand and the activator substance is mixed with the binding substance, reacted and cured, with a second layer 20.2 a hardened sand core is provided, as shown in Figure 1g.

These steps presented above are repeated several times in succession, until here, as shown in Figure 1 h, a total of ten layers 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 18.10 the loose mass of sand and the activator substance and ten layers 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10 of hardened sand cores are stacked, said layers 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10 out of sand cores

Mixing a loose mass of sand and the activator substance of a respective layer 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 18.10 with the binding substance.

It is provided that the layers 20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10 are connected to each other from the sand cores and form a total and the partial mold 22 shown in Figure 1 i. For this purpose, the partial mold 22 can be seen from the work table 4. The remaining loose mass of sand and the activator substance is then removed from the part mold 22, for example, by a suction device and / or manually, wherein within the part mold 22, inter alia, a cavity 24 is provided by the partial mold 22 and the layers 20.1 , 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10 enclosed sand cores and previously filled with several layers 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 18.10 from the loose mass of sand and the activator substance wherein this loose mass has previously supported the split mold 22. This cavity 24 is formed after removal of the loose mass of sand and the activator substance. Since the sub-casting mold 22 is not further to be processed, it is also referred to as a casting mold, which has at least the sub-casting mold 22. Thereafter, liquid starting material 26 is filled into the cavity 24, this liquid starting material consisting of either liquid metal or liquid plastic.

After cooling the starting material 26, the partial mold 22 is removed and finally the finished molded component 28 is provided.

In a variant of the embodiment of the method, as shown in FIG. 11, an additional sand core 30 of solid bound sand is placed in the sub-casting mold 22, this sand core 30 being produced in a similar manner as the sub-casting mold 22 in a three-dimensional printing process. By connecting the partial mold 22 to the sand core 30, a mold 40 is provided. Thereafter, as shown in FIG. 1 m, liquid matrix substance 26 of liquid metal or liquid plastic is filled into the cavity 24. After curing of the matrix substance 26, the casting mold 40, which the sub-casting mold 22 and the sand core 30 from each hardened Sand comprises, removed and provided in Figure 1 n represented component 32, which additionally has a channel 34 which is formed from the previously inserted sand core 30 of hardened sand. Another example of such a finished component 36 is shown schematically in Figure 2. In this case, this component 36 has a network 38 of channels and thus cavities. As explained with reference to FIGS. 1 a to 1 m, this component 36 is produced from a partial casting mold, which in turn is produced from sand by a three-dimensional printing process. After the sub-casting mold provided for this purpose, several sand cores are inserted into this part-casting mold, from which in turn the channels are formed. The network 38 of channels is shown in FIG. 2b independently of the component 36.

Claims

claims

A method of manufacturing a mold (40) for a component to be molded (28, 32, 36) for a motor vehicle, wherein the mold (40) is made of sand by a three-dimensional printing process.

2. The method of claim 1, wherein the mold (40) has at least one part mold (22), wherein first with a first dispenser (6) on a surface of a work table (4) a loose mass of sand and an activator substance with each other are mixed, and then with a second donor (8) on the loose mass of sand and the activator substance, a binding substance is applied, wherein the mass of sand and the activator substance is cured in areas in which the binding substance is applied ,

3. The method of claim 2, wherein the at least one

Part mold (22) of at least one layer (20.1, 20.2, 20.3, 20.4, 20.5,

20.6, 20.7, 20.8, 20.9, 20.10) is produced from sand cores, wherein for producing the at least one layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10) from sand cores a layer (18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 18.10) of the loose mass of sand and the activator substance is applied to the surface of the work table (4), the at least one layer (18.1, 18.2, 18.3, 18.4 , 18.5, 18.6,

18.7, 18.8, 18.9, 18.10) from the loose mass to provide the

Sand core in areas of the produced at least one layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10) is cured with the binding substance.

4. The method of claim 3, wherein the excess loose mass of sand and the activator substance of the at least one formed Layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10) is removed from sand cores.

5. The method of claim 3 or 4, wherein the at least one partial mold (22) consists of several layers (20.1, 20.2, 20.3, 20.4, 20.5, 20.6,

20.7, 20.8, 20.9, 20.10) is made from sand cores, according to

Producing an n-th layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10) on this nth layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7,

20.8, 20.9, 20.10) first a layer (18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 18.10) of the loose mass (10) of sand and the

Activator substance is applied, in which case the binding substance applied to the layer (18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, 18.9, 18.10) of the loose mass and to provide a sand core in areas to be produced η + 1-th Layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10) is cured.

6. The method according to any one of claims 2 to 5, wherein at least one additional sand core (30) of already hardened sand on the at least one layer (20.1, 20.2, 20.3, 20.4, 20.5, 20.6, 20.7, 20.8, 20.9, 20.10) is arranged.

7. The method according to any one of the preceding claims, wherein

Design data of the component to be cast (28, 32, 36) are converted into a model for the at least one casting mold (40) of the component to be cast (28, 32, 36).

8. The method according to any one of claims 2 to 6, wherein the

Binding substance resin.

A method according to any one of claims 2 to 8, wherein the mold (40) is provided from a plurality of sub-molds (22).

10. A method of manufacturing a component (28, 32, 36) for a

A motor vehicle cast with a mold (40) made by a method according to any one of the preceding claims.