MULTI-DIMENSIONAL FORM, USE OF MULTI-DIMENSIONAL FORM, COMPRESSION DEVICE AND CONTINUOUS SYSTEM FOR PRODUCING AT LEAST TWO DENTAL GLASS CERAMIC BLANKS - Patent application

Abstract

To further improve manufacturing of a glass ceramic blank.SOLUTION: Described is a multiple mold (42) for manufacturing at least two glass ceramic blanks. The glass ceramic blanks are used for dentistry and are manufactured from at least two powder blanks by hot pressing. The multiple mold (42) includes a frame (48) that defines at least part of a housing capacity (50) for at least two powder blanks. And at least one separation element (52) is provided being disposed inside the housing capacity (50) and to divide the housing capacity (50) into at least two sub-capacities that are designed so that each of the sub-capacities houses one of the at least two powder blanks. Described further is use of the multiple mold (42) for manufacturing a dental glass ceramic blank. In addition to these are described a compression device and a continuous system for manufacturing a dental glass ceramic blank.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a multiple mold for producing at least two dental glass-ceramic blanks from at least two powder blanks by hot pressing. [Background technology]

[0002] The invention also relates to the use of multiple molds for producing dental glass-ceramic blanks.

[0003] Furthermore, the present invention relates to a compression device comprising a decompression chamber.

[0004] Additionally, the present invention relates to a continuous system for producing dental glass-ceramic blanks.

[0005] In this context, the use of glass ceramic blanks in dental technology is known, which are particularly suitable for producing aesthetically demanding dental restorations having very good optical and mechanical properties. Summary of the Invention [Problem to be solved by the invention]

[0006] It is an object of the present invention to further improve the production of glass-ceramic blanks. In particular, it is desirable to provide the possibility of efficiently producing glass-ceramic blanks. [Means for solving the problem]

[0007] This problem is solved by a multiple mold for producing at least two dental glass ceramic blanks. The glass ceramic blanks are produced from at least two powder blanks by hot pressing. The multiple mold comprises a frame that defines at least a part of a storage volume for the at least two powder blanks. The multiple mold also comprises at least one separating element that is arranged in the storage volume and divides said storage volume into at least two sub-volumes, each designed to accommodate one of the at least two powder blanks. In this context, a multiple mold is understood to mean a mold with which at least two glass ceramic blanks can be produced simultaneously. A multiple mold is a mechanically integral unit. For example, a multiple mold comprises a single die. Such a die is thus used for the production of at least two glass ceramic blanks. In a multiple mold, the relative positions of the sub-volumes are fixedly defined. In the present specification, a powder blank is understood to mean a quantity of powder from which a glass ceramic blank is produced. This quantity of powder can take the form of a green body or a white body. The quantity of powder may also be a simple powder agglomerate. The structure of a multiple mold consisting of a frame and a separating element is simple. This means that the multiple mold is long-lasting and robust. Thus, the multiple mold makes it possible to simultaneously and reliably produce at least two glass-ceramic blanks, which is particularly efficient compared to the use of a single mold.

[0008] In one embodiment, the frame is rectangular, in particular square. The frame may also be round, for example circular. In all variants, the frame may be referred to as annular. Such a frame is mechanically stable.

[0009] If the frame is rectangular, the separation elements and the sub-volumes can be cubic. It is thus possible to efficiently arrange the separation elements and the sub-volumes in the accommodation volume defined by the frame. The accommodation volume defined by the frame can thus be efficiently utilized by the sub-volumes. If the frame is circular, it is of course also possible to arrange cubic separation elements and cubic sub-volumes in it. However, for this purpose it is necessary to use compensation elements, for example in the form of compensation plates, which adapt the circular shape of the frame to the cubic shape of the sub-volumes and the separation elements.

[0010] The round frame can also function as a tension ring.

[0011] The multiplex mold can also comprise a support plate with a support surface for directly or indirectly supporting at least two powder blanks. Such a support plate can also be referred to as a base plate. Direct support in this context is understood to mean that at least two powder blanks are in contact with the support plate directly, i.e. without intervening elements. In the case of indirect support, at least one intervening element, for example a separating element, is arranged between the support plate and the powder blanks. To support at least two powder blanks together, always one support plate is used. The structure of the multiplex mold is therefore still simple. The multiplex mold is therefore long-lasting and robust. In this way, it is possible to simultaneously and reliably produce at least two glass ceramic blanks.

[0012] In one variant, the multiple mould comprises a heating device for heating at least a part of the containment volume, so that the powder blank can be subjected to a heat treatment.

[0013] The heating device can include at least two separate heating segments for independently heating two different portions of the storage volume. This configuration has the advantage that a controlled temperature distribution can be established within the multiple molds. This makes it possible to achieve a uniform temperature distribution within the multiple molds that meets particularly strict tolerance requirements.

[0014] In one embodiment, the heating device includes at least one induction heating element, which allows for reliable and precise heating of the containment volume and any powder blanks placed therein.

[0015] The induction heating element is designed, for example, as an induction heating ring or as an induction heating plate.

[0016] In another embodiment, the heating device includes at least one electrical resistance heating element that generates heat when an electrical current is passed through it, allowing for precise and reliable heating of the containment volume and any powder blanks placed therein.

[0017] In an alternative design, the separating element is at least partially formed as a resistive heating element. That is to say, it performs two functions: firstly, it divides the accommodation volume into sub-volumes; secondly, it serves to heat the accommodation volume and any powder blanks present therein. It will be clear that for this purpose the separating element must comprise an electrically conductive material. Such an arrangement has the advantage that it can bring about a heating effect in the accommodation volume. This allows efficient and reliable heating of the powder blanks placed in the accommodation volume.

[0018] In one variation, only a portion of the isolation element comprises conductive material, which allows pinpointing the current path through the isolation element, thereby allowing the exact location of heat generation to be pinpointed.

[0019] In one variant where the multiplex type comprises a plurality of isolation elements, only some of the isolation elements may contain electrically conductive material, while other isolation elements are in the form of electrical insulators, allowing pinpoint influence of the current path and thus precise definition of the location of heat generation.

[0020] The multi-type can comprise at least two resistive heating elements, which can have different electrical resistances. This allows the amount of heat or heating power to be generated locally to be easily and reliably set. Firstly, this can be used to generate different temperature levels within the multi-type. Secondly, a uniform temperature distribution can be achieved with high precision.

[0021] In this regard, the different electrical resistances can be provided by the inherent resistances of different materials, i.e. the resistive heating elements are made from different materials, or alternatively, the different resistances in the broad sense can be provided by different geometries of the resistive heating elements.

[0022] In the multiplex application for producing dental glass ceramic blanks, it is emphasized that the powder blank does not have electrical conductivity, it is therefore an electrical insulator, so no electrical current flows through it and it does not generate heat.

[0023] In one variant, the separating element comprises or is made of a graphite material. This has two advantages. Firstly, the graphite material is electrically conductive, so that the separating element can obtain a heating effect. Furthermore, the graphite material has good non-stick properties, which makes it possible to prevent the powder blank from adhering undesirably to the separating element.

[0024] A separation element comprising a graphite material may comprise a separation element body made of a metal or ceramic material coated with a graphite material. If the separation element body is made of a ceramic material, the separation element body may be electrically conductive or electrically insulating.

[0025] It is of course also possible for the separating element to be manufactured entirely from a graphite material.

[0026] In one variant, the frame is provided with a clamping device for clamping the separating element and the at least two powder blanks in the receiving volume. The separating element and the at least two powder blanks are held in place during the production of the glass ceramic blank. In one example, the clamping device comprises a mechanical clamping element, for example a screw, which is movable relative to the frame to bring about the clamping. It is also possible to form the clamping device by utilizing the thermal expansion properties of the frame and the separating element. In this context, in particular, the frame can be manufactured from a material that has only a relatively small coefficient of thermal expansion. In particular, the coefficient of thermal expansion of the frame is much smaller than that of the separating element. When such a multi-mold is heated, the desired clamping occurs. In this context, the frame is manufactured, for example, from a ceramic material. The frame may be manufactured from carbon fiber reinforced carbon. Carbon fiber reinforced carbon is understood to mean a material having a carbon or graphite matrix reinforced with carbon fibers.

[0027] Thus, the clamping device can be at least partially formed as a resistive heating element, so that at least a part of the clamping device is electrically conductive. If the parts of the clamping device in the form of resistive heating elements are in direct contact with the powder blank, they can be manufactured, for example, from a graphite material.

[0028] In the receiving volume, a compensation plate can be provided adjacent to at least one of the powder blanks and / or adjacent to the separating element. This compensation plate can serve for position compensation and / or force compensation. In a first option, the compensation plate thus has the effect that the sub-volume for the powder blanks is accurately positioned. In a second option, the aim is to be able to introduce a controlled force, for example a tension, into the powder blank.

[0029] In this way, the compensation plate can be at least partially formed as a resistive heating element, i.e., the compensation plate is used to generate heat that serves the heat treatment of the powder blank. For this purpose, the corresponding parts of the compensation plate must also be electrically conductive. These parts can be made, for example, from a graphite material. If they come into contact with the powder blank, this is further advantageous, since it avoids the powder blank from adhering undesirably to the compensation plate.

[0030] In one embodiment, the two or more separation elements and sub-volumes are arranged alternately in a first direction extending from a first end surface of the frame to a second end surface of the frame. The first end surface and the second end surface are opposite each other. Thus, the powder blanks and the separation elements are arranged alternately in one dimension. This allows two or more glass ceramic blanks to be produced simultaneously and efficiently.

[0031] Two or more separation elements and sub-volumes can also be arranged alternately in a second direction perpendicular to the first direction, so that the sub-volumes and separation elements are arranged in a two-dimensional pattern, which allows a relatively large number of glass-ceramic blanks to be produced simultaneously.

[0032] Two or more separation elements and sub-volumes can also be arranged alternately in a third direction perpendicular to the first and second directions. Thus, in this case, the separation elements and sub-volumes are arranged in a pattern extending in three dimensions. Thus, the multiplex mold is especially designed for the simultaneous production of a large number of glass-ceramic blanks.

[0033] The object of the present invention is also achieved by the use of a multiple mold, in particular the multiple mold of the present invention, for producing a glass ceramic blank for dentistry, in particular for a dental restoration. In this context, it can also be referred to as a dental machining blank, a dental CAD / CAM blank or a dental restoration blank. Such a glass ceramic blank is typically first processed by material removal, for example by machining and / or grinding, to produce a dental restoration, and then subjected to a heat treatment. In the course of the heat treatment, the glass ceramic blank is hardened, in particular as a result of a crystallization process. By means of the multiple mold, it is possible to produce a relatively large number of dental glass ceramic blanks. This is particularly cost-effective from the point of view of costs.

[0034] Furthermore, the object of the present invention is achieved by a compression device with a decompression chamber. In this case, the multiple mold of the present invention is arranged in the decompression chamber of the compression device. In this context, the compression device is a stationary compression device in which multiple molds can be used. In addition to the decompression chamber, the compression device can also include a heating device. In this case, the compression device can also be referred to as an oven. Overall, at least two glass-ceramic blanks can be simultaneously produced using multiple molds in the compression device. This is relatively efficient, in particular in comparison with compression devices in which only a single mold, i.e. a mold capable of producing only a single glass-ceramic blank, is used. In the context of the present invention, the compression device can be integrated into a plant for producing glass-ceramic blanks. In this context, the compression device can be arranged in a decompression chamber, which ensures that the compression takes place under a decompression atmosphere. Such a decompression chamber is considered as a decompression chamber of the compression device, regardless of whether further components of the system for producing glass-ceramic blanks are arranged in this decompression chamber or not.

[0035] The compression device may include a support plate having a support surface for directly or indirectly supporting the mould, thereby allowing the mould to be safely and securely supported within the compression device, this being particularly true for moulds designed without a support plate.

[0036] The compaction device may also comprise a pressure ram, which is movably mounted so that an object placed in a multi-type receiving volume can be subjected to a force by said pressure ram. The receiving volume is thus limited by said pressure ram. As a result, it is possible to produce a geometrically defined glass ceramic blank. Furthermore, the pressure ram can apply a controlled force, i.e. a mechanical pressure, to the powder blank. Thus, the compaction device is suitable for compacting the powder blank.

[0037] In the production of glass-ceramic blanks in a pressing apparatus, for example, the powder blank can first be heated to a temperature of 700° C. or higher. Once this temperature has been reached, a pressing force can be applied to the powder blank. The method can be carried out in a vacuum chamber under reduced pressure, i.e. in a technical vacuum.

[0038] It is emphasized that the compaction machine equipped with a heating device does not mean that the multiple heating device is omitted, instead the two heating devices are complementary to each other in the sense that the multiple heating device is used to heat the powder blank and the heating device of the compaction machine heats the entire multiple mold, thus reducing or avoiding heat losses.

[0039] In addition, the object of the present invention is solved by a continuous system for producing dental glass ceramic blanks. The continuous system comprises a heating station, a pressing station and a cooling station, each of the heating station, the pressing station and the cooling station being designed to accommodate at least one mold, in particular the multiple mold of the present invention. The continuous system further comprises a conveying device for transferring the mold and / or at least one powder blank from the heating station into the pressing station and from the pressing station into the cooling station. The continuous system can be operated with a single mold, i.e. a mold designed to produce only a single glass ceramic blank, or with multiple molds, in particular the multiple mold of the present invention.

[0040] With regard to the fact that the conveying device can be designed to transport the mould and / or at least one blank, several options are evident. In a first option, the mould is transported by the conveying device from the heating station to the pressing station and from there to the cooling station. The mould then has one or more powder or glass ceramic blanks, which are therefore transported together with the mould. In a second option, at least one mould is fixedly assigned to the pressing station. This means that the blank must pass through the heating station without a mould and be inserted into the mould of the pressing station. Similarly, the blank must be released from the mould of the pressing station after hot pressing and pass through the cooling station without a mould. The first option can therefore be called a continuous system with a moving or passing mould, and the second option can also be called a continuous system with a fixed mould.

[0041] It will be clear that in the second option the powder blank must be demolded in a hot state. For this purpose the mould must be opened. Free shrinkage and subsequent removal of the blank is not possible. This means that in the second option the blank is accessible at all stations.

[0042] In the second option, a cleaning step must also be provided, whereby the mould is again prepared to receive a new powder blank and be converted into a glass-ceramic blank by hot pressing. It is preferred to mechanically clean the mould, at least after the pressing has been carried out under reduced pressure or vacuum. This cleaning may be carried out under vacuum conditions.

[0043] The continuous system can be operated with a method for producing a glass-ceramic blank, in which the powder blank is first heated, for example in a heating station, to a temperature of 700° C. or more, and only after reaching that temperature can a compressive force be applied, for example in a compression station. Thus, in this context too, a temperature of 700° C. or more can be used as a trigger criterion for applying a compressive force.

[0044] Since heating and cooling of the moulds with blanks placed therein usually takes longer than compression, the heating and cooling stations are designed to accommodate moulds with more blanks than the compression station, making it possible to compensate for different processing times at the individual stations and thus to achieve a smooth transport of the moulds and / or blanks through the continuous system. This is of course applicable to both variants with moving moulds and variants with fixed moulds.

[0045] The heating station may have at least two fixed temperature zones. Alternatively or additionally, the cooling station may have at least two fixed temperature zones. Thus, the mould in which the powder blank is placed can be exposed to a defined temperature profile by passing through at least two fixed temperature zones. Alternatively to this, it is of course also possible for the mould to be exposed to a defined temperature profile at a single point. In both variants, the mould with the powder blank can be exposed to a defined temperature profile in the heating station and / or the cooling station.

[0046] The invention will now be described with reference to various embodiments shown in the accompanying drawings. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is an explanatory diagram showing a continuous system according to a first embodiment of the present invention, which includes a compression device according to the present invention in which multiple types of compression devices can be arranged. [Diagram 2]FIG. 11 is an explanatory diagram showing a continuous system according to a second embodiment of the present invention, which includes a compression device according to the present invention in which multiple types of compression devices can be arranged. [Diagram 3] FIG. 1 is a perspective view showing a multiplex type of the present invention. [Figure 4] FIG. 4 is a cross-sectional view along plane IV in FIG. 3, with the addition of a portion of the compression device of the invention to allow a better understanding of the multiple version of the invention. [Diagram 5] FIG. 5 is an explanatory view of the multi-layer mold of the present invention shown in FIGS. 3 and 4 in a partially filled state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] 1 shows a continuous system 10 for producing a dental glass-ceramic blank 12. Such a glass-ceramic blank 12 can be used, for example, to make a dental restoration.

[0049] In particular, such glass ceramic blanks 12 can be used to make crowns, abutments, abutment crowns, inlays, onlays, veneers, bridges, as well as overdentures.

[0050] The continuous system 10 comprises, in a process direction P, an inlet lock 14 , a heating station 16 , a compression station 18 , a cooling station 20 and an outlet lock 20 .

[0051] The heating station 16 , the compression station 18 , and the cooling station 20 are disposed within a reduced pressure chamber 24 .

[0052] The inlet lock 14 and the outlet lock 20 are therefore designed as pressure locks or vacuum locks.

[0053] The continuous system 10 further comprises a conveying device 26, which in the illustrated embodiment includes a conveyor belt 28, shown in simplified form.

[0054] In the first embodiment shown in FIG. 1, the conveying device 26 is designed to convey moulds 30 through the continuous system 10, in each of which a powder blank 32 is first placed and thereafter, i.e. after the hot pressing operation, a glass-ceramic blank 12 is placed.

[0055] The moulds 30 with each powder blank 32 are transferred from an introduction area 34 located upstream of the entry lock 14 in the process direction P, through the entry lock 14 and into the heating station 16. The moulds 30 with each powder blank 32 are then transferred from the heating station 16 to the compression station 18.

[0056] The powder blank 32 is converted into the glass-ceramic blank 12 in the compaction station 18 by hot pressing.

[0057] Thereafter, the molds 30 with each glass-ceramic blank 12 are transferred from the compression station 18 to the cooling station 20. The molds 30 with each glass-ceramic blank 12 proceed from the cooling station 20 and are transferred through the exit lock 22 to an exit area 36 where the molds 30 with each glass-ceramic blank 12 may be removed from the continuous system 10.

[0058] For clarity, only a portion of the mold 30, only a portion of the powder blank 32, and only a portion of the glass-ceramic blank 12 are labeled with reference numbers in FIG.

[0059] In order to ensure uniform progression of the molds 30 with each powder blank 32 or glass ceramic blank 12 through the continuous system 10, while at the same time taking into account the fact that the molds 30 with each powder blank 32 or glass ceramic blank 12 are processed for different times at different stations, the individual stations are designed to accommodate different numbers of molds 30 with their respective assigned powder blanks 32 or glass ceramic blanks 12.

[0060] Specifically, in the illustrated embodiment, the introduction area 34 is designed to accommodate a single mold 30 having an associated powder blank 32 .

[0061] The entry lock 34 is also designed to accommodate a single die 30 with an associated powder blank 32 .

[0062] Heating station 16 is designed to accommodate a total of nine molds 30 with associated powder blanks 32 .

[0063] The heating station 16 comprises a first fixed temperature zone 16a and a second fixed temperature zone 16b, where the temperature of the first fixed temperature zone 16a is lower than the temperature of the second fixed temperature zone 16b.

[0064] Thus, the mold 30 with its associated powder blank 32 is heated in two stages as it passes through the heating station 16 .

[0065] The compression station 18 is designed to accommodate a total of three dies 30 .

[0066] At any one time, only a single mold 30 having an associated powder blank 32 is positioned within the compaction apparatus 18a. The powder blank 32 is converted into a glass-ceramic blank 12 within the compaction apparatus 18a.

[0067] A mold 30 with an associated powder blank 32 is present within the compacting station 18, but is located in the process direction P upstream of the compacting device 18a.

[0068] A further mould 30 with its associated glass-ceramic blank 12 is present within the pressing station 18 but is located in the process direction P beyond the pressing device 18a.

[0069] The cooling station 20 is designed to accommodate a total of nine molds 30 with their associated powder blanks 12, too.

[0070] Similar to the heating station 16, the cooling station 20 has a first fixed temperature zone 20a and a second fixed temperature zone 20b, where the temperature of the second fixed temperature zone 20b is lower than the temperature of the first fixed temperature zone 20a.

[0071] Figure 2 shows a continuous system 10 for manufacturing dental glass ceramic blanks 12, designed according to a second embodiment. In the following, only the differences with respect to the embodiment shown in Figure 1 will be described. Elements that are the same or correspond to each other are provided with the same reference signs.

[0072] 2 differs from the embodiment according to Fig. 1 in that the mould 30 is fixedly arranged within the compression station 18. The mould 30 is therefore also fixedly arranged within the continuous system 10.

[0073] Therefore, the conveying device 26 in the second embodiment is only designed to convey the powder blank 32 and the glass ceramic blank 12 , but not the mold 30 .

[0074] Therefore, in the second embodiment, the conveyor belt 28 is divided into two conveyor belt portions 28a, 28b, in this case the conveyor belt portion 28a being assigned to the introduction area 34, the entrance lock 14, the heating station 16 and partly to the compression station 18.

[0075] The conveyor belt section 28b is assigned to the cooling station 20, the exit lock 22, the exit area 36 and also partially to the compression station 18.

[0076] Furthermore, the transport device 26 of the second embodiment includes a total of four gripper units 38a, 38b, 38c, and 38d.

[0077] The gripper unit 38a is arranged in the process direction P upstream of the entrance lock 14 and in the introduction area 34.

[0078] The gripper unit 38d is arranged in the process direction P beyond the exit lock 22 and in the exit area 36.

[0079] The two gripper units 38b, 38c are disposed within the reduced pressure chamber 24. Each of the two gripper units 38b, 38c is coupled to a linear motion unit 40. Thus, the gripper units 38b, 38c can be moved in the process direction P within the reduced pressure chamber 24 by the linear motion units 40 assigned to them, respectively.

[0080] One of the linear motion units 40 coupled to the gripper unit 38b is positioned upstream of the compression device 18a in the process direction P, and the other of the linear motion units 40 coupled to the gripper unit 38c is positioned beyond the compression device 18a in the process direction P.

[0081] In the continuous system 10 according to FIG. 2, the powder blank 32 thus passes through the process carried out by the continuous system 10 .

[0082] In the illustrated process, the powder blank 32 is first placed on the conveyor belt section 28a by the gripper unit 38a and then transported into the entrance lock 14 by the conveyor belt section 28a.

[0083] The powder blanks 32 are then transported through the heating station 16 by conveyor belt sections as described above in connection with the first embodiment shown in FIG.

[0084] As in the first embodiment, the heating station 16 has a first fixed temperature zone 16a and a second fixed temperature zone 16b. Thus, within the heating station 16, the powder blank 32 is first heated in the first fixed temperature zone 16a, and after a certain period of time, is heated in the second fixed temperature zone 16b.

[0085] The gripper unit 38b is then used to insert the powder blank 32 into the mould 30 of the compaction station 18, in particular into the mould 30 of the compaction device 18a. The powder blank 32 is hot pressed in that mould.

[0086] Thereafter, the glass-ceramic blank 12, which has been formed by hot pressing from the powder blank 32, is removed from the mold 30 of the compaction device 18 by the gripper unit 38c and placed on the conveyor belt section 28b.

[0087] The glass-ceramic blank 12 passes on the conveyor belt portion 28b through the cooling station 20, more specifically through a first fixed temperature zone 20a and a second fixed temperature zone 20b of the cooling station 20.

[0088] After the glass-ceramic blank 12 has sufficiently cooled, it is transported by a conveyor belt section through the exit lock 32 to the exit area 36 .

[0089] The glass ceramic blank 12 is removed therefrom by a gripper unit 38d.

[0090] In the second embodiment, it goes without saying that the powder blank 32 must always be able to be handled, and therefore the powder blank 32 is provided, for example, as a coherent white or green body (unsintered compact).

[0091] It will also be clear that the gripper units 38a, 38b, 38c, 38d are shown only diagrammatically, and depending on the application it is also possible to provide more or less gripper units 38a-38d.

[0092] The continuous system 10 has been described above with reference to the molds 30 each being designed as a single mold. Such a mold is designed to accommodate a single powder blank 32 or a single glass-ceramic blank 12 at any one time.

[0093] However, it is also possible to use a multiplexed mould 42 in the continuous system 10 according to the first embodiment (see FIG. 1) instead of the mould 30. What has been said above applies analogously.

[0094] The multiple mold 42 and its use to produce dental glass-ceramic 12 are described below with reference to FIGS.

[0095] The glass-ceramic blank 12 produced by the multiple mold 42 can be used, for example, to make a dental restoration.

[0096] In the embodiment shown in Figures 3 to 5, the multi-layer mold 42 does not include a support plate.

[0097] However, for ease of understanding, FIG. 4 shows a support plate 44 of the assigned compression device 18a, which has a support surface 46 for supporting the multiple molds 42 and in particular the powder blanks 32 present therein.

[0098] Similarly, and again for ease of understanding, pressure ram 62 of compression device 18a is shown in FIG.

[0099] The multiplex 42 comprises a frame 48 which, in the embodiment shown, has a square cross section.

[0100] In this case, the frame 48 defines a storage volume 50 .

[0101] In the embodiment shown, the multiplex 42 further comprises a number of separation elements 52. All separation elements 52 are arranged in the receiving volume 50 and are designed to divide the receiving volume 50 into a number of sub-volumes 54. For this purpose, adjacent separation elements 52 respectively overlap in their end regions (see FIG. 4).

[0102] Each of these sub-volumes 54 is designed to accommodate a powder blank 32 .

[0103] In the embodiment shown in FIGS. 3 and 4, each sub-volume 54 is filled with such a powder blank 32.

[0104] Thus, the storage volume 50 is also a storage volume 50 for the powder blank 32 .

[0105] In the illustrated embodiment, the sub-volumes 54 and separation elements 52 form a regular three-dimensional pattern.

[0106] This means that in three directions R1, R2, R3 corresponding to the three spatial dimensions, a number of separation elements 52 are arranged alternately with the sub-volumes 54 or the powder blanks 32 provided therein.

[0107] The first direction R1 extends from a first end surface 48a of the frame 48 to a second end surface 48b of the frame 48. The first end surface and the second end surface face each other.

[0108] The second direction R2 is perpendicular to the first direction R1 and thus extends from a third end surface 48c of the frame 48 to a fourth end surface 48d of the frame 48. The third end surface 48c and the fourth end surface 48d face each other. Furthermore, the third end surface 48c and the fourth end surface 48d are each between the first end surface 48a and the second end surface 48b.

[0109] The third direction R3 is perpendicular to the first direction R1 and the second direction R2.

[0110] The frame 48 is further provided with a clamping device 56, which is designed to clamp the separation element 52 and the powder blank 32 within the accommodation volume 50. In other words, the powder blank 32 and the separation element 52 are held in the frame 48 by the clamping device 56 in a frictional engagement manner.

[0111] In the illustrated embodiment, the clamping device 56 has a total of four clamping plates 58 between which the powder blank 32 and the separation element 52 can be clamped by actuating a total of ten clamping screws 60.

[0112] In order to enable the pressure exerted by the clamping screw 60 to be introduced as uniformly as possible onto the clamping plate 58 as well as onto the separation element 52 and the powder blank 32 , each end of the clamping screw 60 acts on the clamping plate 58 by means of two pressure plates 59 .

[0113] Furthermore, for the same purpose, compensation plates 61 a , 61 b ​​, 61 c , 61 d are provided adjacent to the powder blank 32 and the separating element 52 on each side.

[0114] During the hot pressing operation, the containment volume 50 is limited by the pressure ram 62 of the compression device 18a and the support plate 44 of the compression device 18a (see FIG. 4).

[0115] The pressure ram 62 is movably mounted such that it can subject the objects placed in the accommodation volume 50 , i.e. in particular the separation element 52 and the powder blank 32 , to a compressive force F in the direction of the accommodation plate 44 .

[0116] For this purpose, the above-mentioned overlap between the edge regions of adjacent separation elements 52 is configured such that adjacent separation elements 52 are slidable relative to one another in direction R3, so that the powder blank 32 arranged in the sub-volume 54 can be compressed (see FIG. 4).

[0117] Thus, the separation element 52 functions as a compression ram element for each adjacent sub-volume 54 .

[0118] For the sake of clarity, the multiplex 42 also includes a heating device 64, which is shown only in FIG.

[0119] The heating device 64 is designed to heat the receiving volume 50 and thus the powder blank 32 disposed therein.

[0120] The heating device 64 in the illustrated embodiment is designed as an electrical resistance heater.

[0121] In this regard, the electrical resistance heater includes a number of electrical resistance heating elements 66 .

[0122] In the embodiment shown, a portion of the separating element 52 forms a resistive heating element 66. Only the separating elements 52 which are cross-hatched are designed as electrical insulators.

[0123] Furthermore, the compensation plates 61a, 61b, 61c, 61d of the clamping device 56 form an electrical resistance heating element 66. The compensation plates 61a, 61b, 61c, 61d are therefore electrically conductive.

[0124] In this regard, each separation element 52 comprises a graphite material. More specifically, in the present context, the electrically conductive separation elements 52 are manufactured from a graphite material.

[0125] Thus, each conductive separation element 52 forms a separate heating segment 68 capable of heating each adjacent powder blank 32 .

[0126] It is therefore possible to control the distribution of heating power within the storage volume 50 .

[0127] In the embodiment shown in FIG. 4, the circuit of the heating device 64 is completed through the pressure ram 62 and support plate 44 of the compression device 18a, which are therefore at least partially conductive.

[0128] In contrast, the clamping plates 58 are designed to be electrically non-conductive. They function to electrically isolate the heating device 64 from the clamping device 56.

[0129] 4, for the sake of clarity, only some of the electrical resistance heating elements 66 and some of the heating segments 68 are labeled with reference numbers. In an alternative embodiment (not shown), the heating device 64 comprises at least one inductive heating element. The heating device 64 is therefore designed as an inductive heater.

[0130] It should be noted that the heating device 64 of the multiple mold 42 does not replace the heating device of the heating station 16 in the continuous system 10, but rather complements it. Thus, the glass-ceramic blank 12 is produced using both the heating device 64 of the multiple mold 42 and the heating device in the heating station 16. [Explanation of symbols]

[0131] 10 Continuous Systems 12 Glass ceramic blank 14 Entrance Lock 16 Heating Station 16a First fixed temperature zone of the heating station 16b Second fixed temperature zone of the heating station 18 Compression Station 18a Compression device 20 Cooling Station 20a First fixed temperature zone of the cooling station 20b Second fixed temperature zone of cooling station 22 Exit Lock 24 Decompression Chamber 26 Transport Equipment 28 Conveyor Belt 28a Conveyor belt section 28b Conveyor belt part 30 Mold 32 Powder Blanks 34 Introduction area 36 Exit area 38a Gripper unit 38b Gripper unit 38c Gripper unit 38d Gripper unit 40 Linear motion unit 42 Multiplex type 44 Support Plate 46 Support surface 48 Frames 48a 1st end face 48b 2nd end face 48c 3rd end face 48d 4th end face 50 Capacity 52 Separation elements 54 Sub-volume 56 Clamping device 58 Clamp plate 59 Pressure Plate 60 Clamp screw 61a Compensation plate 61b Compensation plate 61c Compensation plate 61d Compensation plate 62 Pressure Ram 64 Heating device 66 Electrical Resistance Heating Elements 68 Heating Segment F Compressive force P process direction R1 spatial dimension R2 spatial dimension R3 spatial dimension

Claims

1. A multiple mold (42) for producing at least two dental glass ceramic blanks (12) from at least two powder blanks (32) by hot pressing, comprising: a frame (48) defining at least a portion of a storage volume (50) for said at least two powder blanks (32); at least one separating element (52) arranged in said receiving volume (50) and dividing said receiving volume (50) into at least two sub-volumes (54) each designed to receive one of said at least two powder blanks (32); A multiple type having:

2. 2. The multi-part mold (42) of claim 1, comprising a support plate (44) having a support surface (46) for directly or indirectly supporting the at least two powder blanks (32).

3. 3. The multi-part system (42) of claim 1 or 2, further comprising a heating device (64) for heating at least a portion of the storage volume (50).

4. 4. The multiple type (42) of claim 3, wherein the heating device (64) includes at least two separate heating segments (68) for independently heating two different portions of the containment volume (50).

5. The multi-part (42) of claim 3, wherein the heating device (64) includes at least one induction heating element.

6. The multi-part (42) of claim 3, wherein said heating device (64) comprises at least one electrical resistance heating element (66).

7. 7. The multi-layer mold (42) of claim 6, wherein the separation element (52) is formed at least in part as a resistive heating element (66).

8. 7. The multi-layer mold (42) of claim 6, wherein the multi-layer mold (42) comprises at least two resistive heating elements (66), the at least two resistive heating elements (66) having different electrical resistances.

9. 3. The multi-part type (42) according to claim 1 or 2, wherein the separation element (52) comprises or is made of a graphite material.

10. 3. The multiple mold (42) according to claim 1 or 2, wherein a clamping device (56) for clamping the separation element (52) and the at least two powder blanks (32) in the storage volume (50) is provided on the frame (48).

11. The multi-part (42) of claim 10, wherein the clamping device (56) is formed at least in part as a resistive heating element (66).

12. 3. A multiple mold (42) according to claim 1 or 2, wherein a compensation plate (61a, 61b, 61c, 61d) is provided adjacent to at least one of the powder blanks (32) and / or adjacent to the separation element (52) within the storage volume (50).

13. 13. The multi-layer (42) according to claim 12, wherein the compensation plates (61a, 61b, 61c, 61d) are at least partially formed as resistive heating elements (66).

14. 3. The multiple type (42) of claim 1 or 2, wherein two or more separation elements (52) and sub-volumes (54) are alternately arranged in a first direction (R1) extending from a first end face (48a) of the frame (48) to a second end face (48b) of the frame (48), and the first end face (48a) and the second end face (48b) are opposed to each other.

15. 15. The multiple type (42) of claim 14, wherein two or more separation elements (52) and sub-volumes (54) are arranged alternately in a second direction (R2) perpendicular to the first direction (R1).

16. 16. The multiple type (42) of claim 15, wherein two or more separation elements (52) and sub-volumes (54) are arranged alternately in a third direction (R3) extending perpendicular to the first direction (R1) and the second direction (R2).

17. 3. Use of a multiple mold (42) according to claim 1 or 2 for producing glass-ceramic blanks (12) for dentistry, in particular for dental restorations.

18. A compression device (18a) comprising a decompression chamber (24), wherein a multiplex (42) according to claim 1 or 2 is disposed in the decompression chamber (24) of the compression device (18a).

19. A continuous system (10) for producing dental glass ceramic blanks (12), comprising: a heating station (16), a compression station (18) and a cooling station (20), each of the heating station (16), the compression station (18) and the cooling station (20) being designed to accommodate at least one mould (30), in particular a multiple mould (42) according to claim 1 or 2; a conveying device (26) for transferring the mould (30) and / or at least one powder blank (32) from the heating station (16) into the pressing station (18) and from the pressing station (18) into the cooling station (20); A continuous system comprising:

20. 20. The continuous system (10) of claim 19, wherein the heating station (16) comprises at least two fixed temperature zones (16a, 16b) and / or the cooling station (20) comprises at least two fixed temperature zones (20a, 20b).

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