EP3525998B1 - Device and method for producing ceramic parts - Google Patents

Description

The invention relates to a casting mold, in particular a slip casting mold, according to claim 1, a casting device, a method for dewatering a cast part and a method for producing a cast part.

The state of the art is first on DE 35 02 348 A1 , which discloses a mold for producing a casting according to the preamble of claim 1 and a method for dewatering a casting according to the preamble of claim 8, JP S54 45261 U such as JP S50 140507 A pointed out.

Castings, in particular ceramic castings, are usually produced using at least two mold parts. During the manufacture of ceramics, slip is introduced into these mold parts. Slip is a liquid (mushy to viscous) mass (water-mineral mixture) for the manufacture of ceramic products. The slip is pressurized and pressed into the mold, squeezing water out of the slip. The mold is held together by closing forces (e.g. hydraulic or pneumatic or the like). The water escapes from the mold due to the slip pressure and a so-called green body is created. In order to demould the green body (the shard), the mold parts must be opened so that the green body can be demoulded. The mold parts are then usually cleaned (e.g. with water and/or air). The mold parts can then be closed again so that a new casting cycle can begin.

DE 37 26 383 C2 describes a method and a device for the slip casting of ceramic parts. The corresponding device has several (Specifically four) mold parts, in which communicating channels are arranged, which are connected to a flexible pressure relief hose. The mold parts are here made of a porous material such as plaster. The dewatering process is perceived as being comparatively complex, in particular time-consuming.

Furthermore, it is known to form molded parts in such a way that they have a base body on which a filtration layer is applied, via which the water is drained during drainage. Below is still based on the 1 an example of such a design of a mold explained. The water is usually discharged through a connection on the respective base body. Since the mold parts move relative to each other (e.g. when removing the product, cleaning, etc.), the water is drained off via (flexible) hoses. Faster and more flexible onward transport of the finished green product is therefore only possible to a limited extent. Overall, therefore, the production of the green compact is comparatively complex and not very flexible here either.

It is therefore the object of the invention to propose a casting mold, in particular a slip casting mold for the production of a cast part, in particular a ceramic die-cast part, with which effective dewatering and in particular flexible further transport of the cast part is made possible. Furthermore, a corresponding casting device, a corresponding method for dewatering a cast part and a corresponding method for producing a cast part are to be proposed.

This object is solved by the features of claim 1. In particular, the object is achieved by a casting mold, in particular a slip casting mold, for producing a cast part, in particular a ceramic die-cast part, comprising at least a first mold part with a first base part and a first filtration layer and at least a second mold part with a second base body and a second filtration layer, wherein in at least one first drainage channel is provided on the first base body, with at least one drainage channel end which, in a pouring position, opens into a drainage channel within the second mold part.

A core aspect of the invention lies in the use of mold parts that are basically constructed in two parts (i.e. with a base body and a filtration layer) and in the first mold part the water is not drained off via a connection with a corresponding drain, but via the second mold part (or an additional drainage body , which is not part of the invention). As a result, the first mold part can be moved freely after the dewatering process (since it is not connected to a discharge line, such as a hose, for example) and can be transported further quickly. Nevertheless, the casting is dewatered effectively and quickly. In particular, it is also possible that the cast part is removed with a robot (together with the first mold part). The robot can then flexibly position the casting at a suitable location for further processing. For example, the cast part can also be moved sideways and does not have to be moved away in a direction opposite to the second mold part (as is usual in the prior art). A central idea is therefore that the drainage channel of the first mold part (directly) opens into a drainage channel of the second mold part. In particular, when a drainage channel of the second mold part is used, a structure for draining the water from a drainage channel inside the first mold part is omitted.

An (additional) drainage body is to be understood in particular as a body that is rigid (and possibly without open pores). The drainage body can (just like the second base body) lie directly against the first base body in the casting position and/or be (further) away from the first base body in a demolding position (in particular open mold parts), e.g. at least essentially the same distance away as the second body.

The first and/or second base bodies are (preferably) designed without pores or at least without open pores. The (first and/or second) filtration layer may have a (at least substantially) constant thickness. The (first and/or second) base body can have at least one recess and/or at least one projection for defining the shape of the cast part.

A drainage channel end filter device, in particular a drainage channel end filtration layer, is preferably provided at the drainage channel end. Alternatively or additionally, a drainage channel end valve device can be provided. As a result, a fluid resistance at the end of the drainage channel can be approximated or matched to a fluid resistance of the first filtration layer. If, for example, a fluid (e.g. water or air) is then pressed into the first drainage channel or sucked out from there, this also has an effect on the first filtration layer, since the fluid is not (exclusively) pressed over the end of the drainage channel or sucked out from there. The drainage process can thus also be influenced (controlled) via changes in the pressure in the drainage channel. This increases the efficiency of the dewatering process.

The first drainage channel has at least one fluid supply and/or discharge end, via which a fluid (e.g. air or water) can be supplied and/or discharged. This fluid supply and/or discharge end is preferably (in the pouring position) not in contact with the second mold part so that it is accessible from outside the mold (e.g. by a robot). In concrete terms, the drainage channel can (at least or exactly) have three ends, namely the drainage channel end, the fluid supply and/or discharge end and the end in contact with the first filtration layer. (At least) one corresponding branch is provided for this purpose. A pressure present at the first filtration layer at the corresponding end of the fluid channel can be increased and/or decreased via the fluid supply and/or discharge end, so that the dewatering process can be promoted and/or the removal of the finished green body via the first mold part ( for example via a robot) is facilitated. For this purpose, for example, suction can take place to lift the first molded part with the green compact and then the pressure can be increased to deposit the green compact at another location (for example an assembly line).

A valve is preferably assigned to the fluid supply and/or discharge end, so that the fluid supply and/or discharge end can be selectively opened or closed. This valve is preferably by a Recording device (such as a robot) actuated. This makes it easier to dewater and move the casting.

Preferably, the first drainage channel is adjacent to (without penetrating) the first filtration layer. Alternatively, the first drainage channel can at least partially penetrate the first filtration layer.

The (respective) second drainage channel within the second mold part can penetrate the second mold part without being in contact with the second filtration layer. Alternatively, the second drainage channel can also be in contact with the second filtration layer.

In general, at least two (or at least three or at least four) first drainage channels and/or at least two (or at least three or at least four) second drainage channels can be provided. In the second drainage channels, at least one (or at least two or at least three) drainage channels may not be in contact with the second filtration layer and/or at least one (or at least two or at least three) drainage channels may be in contact with the second filtration layer.

A seal (ring seal) is preferably provided in an area around the drainage channel end.

A drainage channel beginning of the second drainage channel is preferably in direct connection with the drainage channel end of the first drainage channel in the casting position.

A cross-sectional area of a (the) drainage channel start of the second drainage channel is preferably at least approximately (possibly +/- 40%, in particular +/- 10%) as large as a cross-sectional area of the drainage channel end of the first drainage channel.

In embodiments, the length of the first and/or second drainage channel is at least twice, preferably at least four times, the (average) diameter.

A (the) diameter of the first and/or second drainage channel is preferably constant (over the respective length of the first or second drainage channel).

A cross section of the first and/or second drainage channel is preferably (at least in sections, possibly over the entire length) round and/or oval and/or polygonal, in particular rectangular.

The above-mentioned object is also achieved by a casting device, in particular a slip casting device, comprising at least one casting mold, in particular a slip casting mold of the type described above, for producing a cast part, in particular a ceramic die-cast part.

The casting device, in particular a slip casting device, preferably has a removal device, in particular a robot (in order to remove the first mold part together with the cast part from the second mold part and thus remove the cast part). In particular, the removal device is designed so that the casting can be removed laterally (i.e. in a direction that deviates from a pressing direction (for example by an angle of at least 10 degrees or at least 30 degrees or at least 45 degrees or at least 60 degrees). The pressing direction is defined by the pressing of the first and second mold parts against each other. This means that the cast part can be picked up quickly and variably and positioned elsewhere. Preferably, there is at least one fluid supply and/or discharge device for fluid (in particular air and/or water and/or slip ) in the direction of a mold cavity or to be sucked from there, This can improve the dewatering and/or the pick-up and other positioning of the cast part.

The above-mentioned object is further achieved in particular by a method for dewatering a cast part, in particular a ceramic die-cast part, in a mold, in particular of the type described above, with the features of claim 8, wherein the mold has at least a first mold part with a base body and a first filtration layer and at least one second molded part having a second body and a second filtration layer, wherein liquid is drained through and from the body is derived by the second body. The first and second mold parts are preferably pressed against one another during dewatering.

During the drainage, a vacuum or excess pressure can be built up in at least one first drainage channel of the first mold part. Alternatively or additionally, a negative or positive pressure can be built up in at least one second drainage channel of the second mold part during the drainage. For example, an overpressure can be built up in one of the first drainage channels and a negative pressure in another of the first drainage channels, so that the liquid in the filtration layer is pressed from one drainage channel to the other. Alternatively or additionally, an overpressure is built up in one of the second drainage channels and/or a negative pressure in another of the second drainage channels, so that water from the first and/or second filtration layer is conveyed from the first drainage channel to the second drainage channel and is thus effectively removed can. Overall, this enables efficient dewatering.

• Einfüllen einer zu gießenden Masse in einen Hohlraum,
• Entwässern gemäß den oben beschriebenen Verfahren und
• Entfernen des Gussteils aus der Gussform.

The above-mentioned object is also achieved in particular by a method for producing a cast part, in particular a ceramic die-cast part, using a mold, in particular of the type described above, comprising the steps:

• filling a mass to be cast into a cavity,
• Dewatering according to the methods described above and
• Removing the casting from the mold.

The cast part is preferably removed (or removed) laterally (in particular via a robot). In principle, however, the direction of removal is arbitrary.

The above-mentioned object is also achieved in particular by using a casting mold, in particular a slip casting mold of the type described above and/or a casting device, in particular a slip casting device of the type described above, for producing a cast part, in particular a die-cast slip part, with the features of claim 13.

Further embodiments emerge from the dependent claims.

Fig. 1

eine schematische Darstellung eines Vergleichsbeispiels einer Schlickergussform; und

Fig. 2

eine schematische Darstellung einer Schlickergussform gemäß einer ersten Ausführungsform der Erfindung; und

Fig. 3

eine schematische Darstellung einer Schlickergussform gemäß einer zweiten Ausführungsform der Erfindung.

The invention is described below using a comparative example and an exemplary embodiment, which are explained in more detail using the figures. Here show:

1

a schematic representation of a comparative example of a slip casting mold; and

2

a schematic representation of a slip casting mold according to a first embodiment of the invention; and

3

a schematic representation of a slip casting mold according to a second embodiment of the invention.

In the following description, the same reference numbers are used for the same parts and parts with the same effect.

1 shows a comparative example for a slip casting mold in a schematic section. The slip casting mold comprises a first mold part 10 and a second mold part 11. Slip 26 for producing a die-cast part is located between the mold parts 10,11. In the first mold part 10, two first drainage channels 12a, 12b are provided. In the second mold part 11, two second drainage channels 13a, 13b are provided.

The first drainage channels 12a, 12b are arranged in a first base body 14 of the first mold part 10. Furthermore, the first molded part 10 also has a first filtration layer 15 . Similarly, the second mold part 11 includes a second base body 16 and a second filtration layer 17. To produce a (ceramic) casting, the slip 26 is introduced between the first mold part and the second mold part 11 into a cavity 18. The slip is pressurized so that water is pressed out of the slip and can be discharged via the filtration layers 15, 17 or the drainage channels 12a, 12b, 13a, 13b. This creates a so-called shard (green body). For the demolding of the body, the mold parts 10, 11 are opened (i.e. removed from each other) so that the shard can be removed. The mold parts 10, 11 can then be cleaned (usually with water and/or air). The mold parts 10, 11 can be closed again so that a new casting cycle can start.

According to 1 the filtration water (ie the water pressed out of the slip) is thus (individually) discharged from the two mold parts 10, 11. For this purpose, first connections 19a, 19b are provided on the first mold part 10 and second connections 20a and 20b are provided on the second mold part 11. Hoses (or similar lines) are then usually connected to these connections, through which the water can be drained. Such (flexible) lines can be used to compensate for a relative stroke between the first and second mold parts (for example during product removal or cleaning, etc.).

In 2 a first embodiment of a slip casting mold according to the invention is shown in a schematic section.

Here, the first mold part 10 has first drainage channels 12a, 12b, each of which has a drainage channel end 21a, 21b, which in the casting position (in which the first mold part 10 and second mold part 11, as in FIG 1 shown pressed against each other) are (directly) connected to second drainage channels 22a, 22b, so that pressed water (filtration water) can be discharged from the first filtration layer 15 via the first drainage channels 21a, 21b and the second drainage channels 13a, 13b. As a result, it is not necessary to connect a hose or the like to the drainage channel ends 21a, 21b (which is also not possible in the pouring position), but the water is discharged via the second mold part. The first mold part 10 can therefore be lifted together with the shard (green body) comparatively easily and flexibly (in particular by means of a robot) and flexibly positioned elsewhere. All in all, the water gets from the slip in the cavity 18 via the first filtration layer 15 into the first drainage channels 12a, 12b and can be discharged from there via the second drainage channels 13a, 13b.

Once the green body is fully cast (particularly in a die-casting process to produce a ceramic product), it can first mold part 10 using a removal device (a robot; in particular together with the green body) are raised.

For this purpose, it is preferred that a vacuum (negative pressure) is applied to the first mold part 10 so that the green compact adheres to the first mold 10 and can be moved as well. For this purpose, a robot or other removal device can open (press) a valve 22a or 22b, so that a fluid connection is established between the first filtration layer 15 and a fluid supply and/or discharge end 23a or 23b, and from there a negative pressure can be applied can. Furthermore, for the purpose of positioning (or setting down) the green compact in a different way, an overpressure can then be applied accordingly, so that the green compact detaches from the first mold part 10 . Furthermore, water and/or air can also be introduced or extracted via the fluid supply and/or discharge end 23a or 23b (for example for cleaning). A drainage channel end filtration layer 24a or 24b in the first drainage channel 12a or 12b ensures that fluid that is present, for example, via the fluid inlet and/or outlet end 23a or 23b and is to be conveyed in the direction of the filtration layer 15 is not (exclusively ) runs over the first drainage channel end 21a or 21b.

Furthermore (in particular for better drainage of the filtration water in the casting process, in which the mold parts 10, 11 are closed), an (at least slight) overpressure or negative pressure can be built up (in the first drainage channels 12a, 12b and/or second drainage channels 13a, 13b) . For example, it would be conceivable that an overpressure is built up in the second drainage channel 13a and a negative pressure is built up in the second drainage channel 13b, so that overall the filtration water is conveyed in the direction of the second drainage channel 13b.

A second (in 2 middle) drainage channel 13c is in contact with the second filtration layer 17. This drainage channel can define a slip port. Furthermore, the drainage channel 13c can also be arranged at a different point. The second drainage channels 13a and 13b are not in communication with the second filtration layer 17 (nor with the first filtration layer 15).

Seals 25a, 25b are arranged around the drain channel ends 21a, 21b to allow an effective transfer of water from the first drain channels 12a, 12b into the second drain channels 13a, 13b.

In principle, two or more second drainage channels can also be provided, which are in contact with the second filtration layer. An example shows figure 3 . This shows a second embodiment which corresponds to the first embodiment with the difference that two second drainage channels 13c, 13d are provided which are in contact with the second filtration layer 17.

Reference sign

10

First mold part

11

Second mold part

12a, 12b

First drainage canal

13a, 13b, 13c, 13d

Second drainage canal

14

First body

15

First filtration layer

16

Second body

17

Second filtration layer

18

cavity

19a, 19b

connection

20a, 20b

connection

21a, 21b

drainage canal end

22a, 22b

Valve

23a, 23b

Fluid supply and/or discharge end

24a, 24b

Drainage canal end filtration layer

25a, 25b

poetry

26

slip

Claims (13)

1. Casting mold, in particular a slip casting mold, for producing a cast part, in particular a ceramic die cast part, comprising at least one first mold part (10) having a first base body (14) and a first filtration layer (15) and at least one second mold part (11) having a second base body (16) and a second filtration layer (17), wherein at least one first dewatering channel (12a, 12b) having at least one dewatering channel end (21a, 21b) is provided in the first base body, characterized in that the dewatering channel end (21a, 21b) opens in a casting position into a second dewatering channel (13a, 13b) within the second mold part (11).
2. Casting mold, in particular slip casting mold, according to claim 1, characterized in that a dewatering channel end filter device, in particular a dewatering channel end filtration layer (24a, 24b), and/or a dewatering channel end valve device is provided at the dewatering channel end (21a, 21b).
3. Casting mold, in particular slip casting mold, according to claim 1 or 2, characterized in that the first dewatering channel (12a, 12b) has at least one fluid supply and/or discharge end (23a, 23b) via which a fluid, in particular air or water, can be supplied and/or drained, wherein a valve (22a, 22b) is preferably associated with the fluid supply and/or discharge end (23a, 23b) so that a flow path can be opened or closed in the direction of the first filtration layer (15) and/or in the direction of the dewatering channel end (21a, 21b).
4. Casting mold, in particular slip casting mold, according to one of the preceding claims, characterized in that the first dewatering channel (12a, 12b) adjoins the first filtration layer (15) without penetrating it, or in that the first dewatering channel penetrates the first filtration layer at least partially.
5. Casting device, in particular slip casting device, comprising at least one casting mold, in particular slip casting mold, according to one of the preceding claims for producing a cast part, in particular a ceramic die cast part.
6. Casting device, in particular slip casting device, according to claim 5, characterized in that a removal device, in particular a robot, is provided to remove the first mold part (10) together with the cast part from the second mold part (11).
7. Casting device, in particular slip casting device, according to claim 5 or 6, characterized in that at least one fluid supply and/or discharge device is provided to press fluid, in particular air or water, towards a mold cavity or to suck it off from there.
8. Method for dewatering a cast part, in particular a ceramic die cast part, in a mold, in particular according to one of claims 1 to 4, wherein the mold has at least one first mold part (10) having a first base body (14) and a first filtration layer (15) and at least one second mold part (11) having a second base body (14) and a second filtration layer (17), characterized in that, for dewatering, fluid is discharged through the first base body (14) and from there through the second base body (16).
9. Method according to claim 8, characterized in that first (10) and second (11) mold parts are pressed against each other during dewatering.
10. Method according to claim 8 or 9, characterized in that during dewatering a negative or positive pressure is built up in at least one first dewatering channel (12a, 12b) of the first mold part (10) and/or during dewatering a negative or positive pressure is built up in at least one second dewatering channel (13a, 13b, 13c) of the second mold part (11).
11. Method for producing a cast part, in particular a ceramic die cast part, using a mold, in particular according to one of claims 1 to 4, comprising the steps of:

    - filling a mass to be cast into a cavity (18),

    - dewatering according to one of claims 8 to 10, and

    - removing the cast part from the mold.
12. Method according to claim 11, characterized in that the cast part is removed laterally, in particular via a robot.
13. Use of a casting mold, in particular a slip casting mold, according to one of claims 1 to 4 and/or a casting device, in particular a slip casting device, according to one of claims 5 to 7 for producing a cast part, in particular a die cast slip part.

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