METHOD FOR PRODUCE A COLD CASTING MOLD AND COLD CASTING MOLD FOR THE PRODUCTION OF MOLDED PARTS, IN PARTS IN PARTS, IN PARTS IN PARTS

Description

[0001] The invention relates to a method for producing a cold casting mold for manufacturing molded parts, in particular dental molded parts, from a mixing compound. The cold casting mold, comprising a cavity geometrically corresponding to the molded part, in particular the dental molded part, is additively constructed from a starting material using an additive material build-up process, in particular a 3D printing process using a 3D printer, based on a digital data set derived from a spatial model of a patient's oral cavity and at least one first opening leading into the cavity for filling with the mixing compound. The invention also discloses the use and production of such an additively constructed cold casting mold for a method for manufacturing molded parts, in particular dental molded parts, from a sinterable or light-curing mixing compound.

[0002] The production of molded parts using computer-aided processes (CAD / CAM) is known in a variety of technical fields. Dental molded parts, in particular dentures such as crowns and bridges, but also dental implants and prostheses or parts relevant for orthodontics such as brackets, are also produced using computer-aided processes (CAD / CAM) in many dental practices and dental laboratories. First, a digital, three-dimensional model of a patient's oral cavity is created. The required dentures are planned using software, and the created data set is transmitted, for example, to a milling machine, which mills the finished dentures from a blank. The blanks are usually produced using a cold casting process, in which a mixing mass is first produced from a ceramic powder or metal powder suitable for dental technology. The mixing mass can be, for example,A pasty mass, a slurry, a suspension, or even a "dry" powder bed can be used. A method for manufacturing dental prostheses from dental metal powder is known from EP 2 470 113 B1. In this process, a CrCo dental metal powder is mixed to form a slurry, poured cold into a mold, and dried there. A binder added to the slurry provides sufficient dimensional stability after drying, so that the dried slurry, as a green body, is removed from the cold casting mold and milled into the desired shape using a milling machine based on the transmitted digital data set. Final (sealing) sintering gives the dental prosthesis the required hardness and density. The necessary material properties for approval as dental components are precisely defined by national and / or international standards. Such cold casting processes are only suitable for the production of blanks.The fine, complex shapes of the actual dental prosthesis are subsequently milled from the blank by machining. Templates for metal or ceramic slips for dental technology are state of the art and can be found, for example, in publications EP1658018 B1, EP1047355 B1, WO 2013007684 A, EP1558170 B1, and EP1885278 B1. Information on their conditioning can be found in publications DE 10 2005 023 727 B4 and DE19801534 A1. The execution of the final sealing sintering is also sufficiently described in the state of the art; corresponding methods and sintering furnaces can be found in EP 2765950 B1, EP 2844412 A1, and WO2011020688 A1.

[0003] Document CN106175946A1 describes a method and apparatus for manufacturing a dental prosthesis. The method comprises the following steps: producing a dental prosthesis model according to the shape of the patient's teeth, forming an injection molding cavity in the same shape as the dental prosthesis model in a mold, forming an injection molding hole and a vent connected to the injection molding cavity, injecting molten raw materials into the injection molding cavity through the injection molding hole, and removing the molten raw materials after cooling and molding to obtain a dental prosthesis.

[0004] When using powder as a mixing compound, an additional process step, isostatic pressing, is usually required to achieve sufficient dimensional stability. This involves applying high pressure evenly to the mixing compound from all sides. Corresponding processes for producing ceramic dental prostheses from ceramic powders, e.g., zirconium oxide, are also well known in the art. A process for producing dental components from ceramic powder is described in WO 2008 / 114 142 A1.

[0005] The digital, spatial model of the oral cavity is also used for the production of temporary dentures made of plastic. The data set created for the denture is then sent to a 3D printer, which builds the temporary denture layer by layer from the plastic starting material using an additive material build-up process (3D printing).

[0006] In the field of additive manufacturing, inorganic materials can now serve as starting materials in addition to plastics. Well-known additive manufacturing processes include SLM (selective laser melting), extrusion processes such as FDM (fused deposition molding) and FFF (fused filament fabrication). Additive manufacturing processes that utilize the light-curing properties of the starting materials are also known, such as SLA / STL (stereolithography), DLP (digital light processing), and LCM (lithography-based ceramic manufacturing).

[0007] Initial attempts have already been made to produce dental prostheses from metal or ceramic using additive manufacturing processes. A process for manufacturing a dental crown from zirconia using an additive manufacturing process is known from WO2018 / 065856 A1. However, 3D printers for metal or ceramic objects are very expensive and / or the printed part does not meet the stringent material requirements for approval for dental use. In particular, additive manufacturing processes require a very high binder content in the starting material (approx. 30%), which makes achieving the required final density and hardness either impossible or extremely difficult. An economically viable implementation of printing dental prostheses from ceramic or metal is not yet in sight.

[0008] Another possibility, which involves using digital spatial data of the oral cavity to produce complexly shaped and densely sintered dental prostheses with a 3D printer, is disclosed in WO 2019 / 210285 A2. Here, instead of the prosthesis itself, a self-destructive mold is printed using a 3D printer. The starting material for the printing process is a powder mixture of two components: a sinterable alumina powder and a powdered binder with a high coefficient of thermal expansion (CTE). The printed mold is filled with a sinterable, dry zirconia powder bed as the mixing material. The mold is then sealed with a lid printed from the same material, and the mold, along with the zirconia powder bed inside, is isostatically pressed at a pressure of 400 MPa.The key to this process is that the powder bed is free of binding agents to ensure uniform compression. The powder bed is compacted together with the mold and then sintered without removing the mold. During sintering, the binding agents contained in the mold expand, causing the mold to crack.

[0009] In order for the finished sintered part to be released from the mold, the sintering temperature of the mold must be higher than the sintering temperature of the powder bed. Disadvantages of the disclosed process are, on the one hand, the high costs associated with 3D printing the ceramic starting material and isostatic pressing at extremely high pressures of 400 MPa. However, the use of a ceramic starting material with a sintering temperature higher than that of the powder bed is crucial for the described process. On the other hand, the possible applications of the process are limited. The mixing compound used must be free of binders to achieve uniform pressing. Furthermore, compacting pressing processes, especially isostatic pressing, in which the pressure must act evenly on the molded part from all sides, are not suitable for mixing compounds with a moisture content of more than 7%. Liquids are virtually incompressible.Isostatic pressing requires the powder to be completely enclosed within the mold, which is then sealed with a lid. This prevents any moisture contained in the mix from escaping.

[0010] The object of the present invention is therefore to provide an additively manufactured, in particular 3D-printed, cold casting mold that enables the more cost-effective and mass-producible manufacture of dental components with complex anatomical shapes, colors, and light-refracting surface structures, such as crowns, bridges, dental implants, abutments, dentures, etc., compared to the prior art. At the same time, the range of applications is to be expanded. In particular, the use of a wide variety of mixing compounds, made of sinterable and non-sinterable, metallic and / or ceramic materials or plastics, is permitted, either in dry powder form or as a slurry, suspension, or paste.

[0011] The problem is solved by a method for producing a cold casting mold according to claim 1. A method for producing a cold casting mold of the type described above is characterized in that the cold casting mold is additively constructed with at least one second opening leading into and / or out of the cavity for venting gases, in particular air inclusions, and / or liquids, in particular diluents.

[0012] According to the invention, in addition to the first opening provided for filling the cavity with the mixing compound, at least one second opening is provided, which, like the first opening, leads into or out of the cavity in a fluid-conducting manner. In principle, it is conceivable to form the first opening and / or the second opening, in particular to drill it, after the additive manufacturing of the cold casting mold is complete. However, it is advantageous to form the first opening and / or the second opening directly during the additive material manufacturing process, thus avoiding an additional work step. Similar to, for example, (vacuum) bottle filling systems, it is also conceivable to form the second opening (for venting) during the additive material manufacturing process and to form the first opening (for filling) by, in particular, concentrically inserting a filling channel into the second opening. The second opening enables the introduction of fluids, i.e.,To discharge gases and / or liquids during the filling of the cold casting mold (comparable to a ventilation opening when pouring with a TetraPak ®< ). After filling, for the curing and / or solidification of the mixing compound, the at least one first opening and / or the at least one second opening remain unlocked, thereby allowing fluids to escape. On the one hand, this allows air pockets caused, for example, by filling the cold casting mold with the mixing compound to be discharged. On the other hand, liquids such as thinners contained in pasty, moist or slip-like mixing compounds or suspensions can be discharged from the cavity of the cold casting mold, thereby enabling the mixing compound to dry inside the cold casting mold.By forming at least one second opening, the cold casting mold additively constructed according to the inventive method can not only be used for mixing mass with any moisture content, the at least one second opening also allows venting when using a powder bed, which can be supported, for example, by vibration.

[0013] According to a preferred embodiment of the invention, at least one wall of the cold casting mold delimiting the cavity is therefore additively constructed, completely or in regions, with a plurality of second openings opening into the cavity and penetrating this wall for discharging gases, in particular air inclusions, and / or liquids, in particular diluents.

[0014] By perforating one or more walls of the cold casting mold with a plurality of adjacent secondary openings, a sieve-like surface can be formed that allows the passage of liquids and gases while retaining solids. Preferably, the diameter of the respective secondary openings is smaller than the particle size and / or the size of any particle agglomerates forming from the powders contained in the mixture, such as metal powders, ceramic, glass-ceramic powders, or plastic powders.

[0015] In a further development of this design, the numerous secondary openings are therefore also formed in the form of pores and / or capillaries that penetrate the wall, so that the wall has completely or partially porous and / or hygroscopic properties.

[0016] Such a design has the further advantage that moisture contained in the mixing compound is absorbed by the adjacent porous and / or hygroscopic wall and preferably transported outwards from the interior towards the atmosphere surrounding the cold casting mold. This effect can be enhanced by increasing the ambient temperature surrounding the cold casting mold or by other measures to reduce the ambient humidity, thereby creating drier ambient air.

[0017] It is also advantageous to produce the cold casting mold from different base materials with varying physical properties. For example, the moisture absorption capacity of the porous and / or hygroscopic areas can be increased by using a suitable base material. Other areas or structures of the cold casting mold, such as filling channels, compensation volumes, or support structures, can be formed by selecting a different base material with different properties, such as water solubility, color, transparency, etc.

[0018] To facilitate the filling of the cold casting mold, for example by means of a syringe or a cannula or a similar tool, the cold casting mold can be additively constructed with a filling channel adjacent to at least one first opening in a fluid-conducting manner.

[0019] The filling channel is preferably formed integrally with the cold casting mold. The filling channel particularly facilitates pressurized filling of the cold casting mold, for example by injection molding.

[0020] In a further development, the filling channel is fluidly connected to at least one compensation volume for holding mixing mass.

[0021] Preferably, the compensation volume is also additively built up in one piece with the cold casting mold. Particularly when using mixing material with a higher moisture content and / or with air inclusions, the compensation volume acts as a kind of reservoir and allows mixing material to flow or trickle in to compensate for the volume loss caused by the escape of gases and / or liquids from the cavity through the at least one second opening.

[0022] A faster and / or more uniform filling of the cavity of the cold casting mold can be realized according to an alternative variant of the invention by additively constructing the cold casting mold with two or more first openings, each opening into the cavity, for simultaneous or staggered filling with mixing compound.

[0023] By having two or more initial openings intended for filling at different positions within the cavity, it is possible, for example, to fill the cavity with different mixing materials at different points. If the additional initial openings are not used for filling, they can function as secondary openings for venting fluids.

[0024] It is particularly advantageous to use an organic material, in particular an organic wax and / or a polymer and / or a plastic as the starting material for the additive construction of the cold casting mold, so that the cold casting mold is plasticizable and / or thermally and / or thermochemically decomposable.

[0025] Organic materials such as waxes and / or polymers and / or plastics are significantly easier and therefore more cost-effective to use in additive material building processes, such as 3D printing. The heat resistance of plastics is comparatively low, so that a cold casting mold additively constructed from an organic material can plasticize or even decompose thermally and / or thermochemically, particularly through pyrolysis and / or combustion. Advantageously, a starting material with a lower melting point, e.g., wax, can be used for structures and / or walls of the cold casting mold that do not define the cavity or are directly adjacent to it, particularly for support structures, filling channels, compensation volumes, etc., than for the walls of the cold casting mold that define the cavity, which are then additively constructed from polymers or plastics, for example.In this way, stresses that occur during plasticizing or decomposition of the cold casting mold, especially heat-related ones that could lead to damage to the molded part, can be reduced or even completely avoided. The organic starting material may contain small amounts of inorganic materials. For example, it is common practice to add inorganic additives to plastics. However, the proportion of organic components is always higher than the proportion of inorganic components.

[0026] Preferably, the organic material used for the additive manufacturing of the cold casting mold has a melting point and / or a decomposition temperature in a temperature range of 40°C to 300°C, preferably 60°C to 300°C.

[0027] The melting temperature or melting temperature range of the cold casting mold is therefore below the melting and / or sintering temperature of the commonly used mixing materials. Advantageously, the decomposition temperature, i.e., the temperature at which thermal and / or thermochemical decomposition of the cold casting mold begins, is also below the melting and / or sintering temperature of the mixing material used.

[0028] In a further development, the organic material used for the additive construction of the cold casting mold is plasticizable by the action of heat, in particular at a temperature in a temperature range of 35°C to 300°C, preferably 50°C to 300°C, and / or thermally decomposable by the action of heat, in particular at a temperature in a temperature range of 200°C to 650°C, by pyrolysis and / or thermochemically decomposable by combustion. Waxes, for example, represent a group of materials with particularly low heat resistance. By using a wax-containing, organic material, softening or plasticization of the cold casting mold can be achieved starting at a temperature of approximately 35°C.

[0029] The thermal and / or thermochemical decomposition can preferably be carried out completely and / or at high temperatures in a sintering temperature range of 1300°C to 2500°C, so that a residue-free or at least almost residue-free dissolution of the cold casting mold is made possible by the application of heat.

[0030] Alternatively, according to an advantageous embodiment, mechanical destruction of the cold casting mold can also be provided during the additive material build-up process by additively building up at least one wall limiting the cavity of the cold casting mold with a predetermined breaking point, in particular with a reduced wall thickness in certain areas.

[0031] The proposed manufacturing process is based on spatial, digital data, in particular of a patient's oral cavity. The geometric shape data derived from this for molded parts, in particular for dental molded parts, are used directly in the additive material build-up process for the geometric design of the cavity of the cold casting mold. In order to guarantee, for example, in dental technology a precise fit of dental molded parts, in particular crowns, bridges, dental implant parts and / or prostheses in the patient's oral cavity, the digital data set for the geometric design of the cavity of the cold casting mold therefore preferably includes a sintering and / or curing-related volume shrinkage of the mixing compound. Depending on the mixing compound used, a corresponding volume shrinkage during curing orThe solidification and / or sintering of the mixing compound must be taken into account; the cavity of the cold casting mold must be designed with a correspondingly adapted (larger) initial geometry. For mixing compounds containing ceramic powder, for example, sintering shrinkage in the range of 25% to 50% must be considered; for mixing compounds containing sol and nanozirconium oxide particles, in the range of 50% to 95%; and for mixing compounds containing metal powder, in the range of 8% to 25%, each relative to the initial geometry. For the curing of the mixing compound by light and / or drying, a volume shrinkage of approximately 2% to 20% relative to the initial geometry must be considered. A volume shrinkage of 1% to 10% relative to the initial geometry can also be considered for the cold casting mold itself during the production of the molded part.The cold casting mold produced according to the inventive method enables cost-effective production of molded parts, in particular dental molded parts, from a wide variety of mixing compounds.

[0032] The object of the invention stated at the outset is therefore also achieved by a cold casting mold according to claim 7.

[0033] The cold casting mold according to the invention has at least one first opening leading into the cavity for filling with the mixing mass and is characterized by at least one second opening leading into the cavity for venting gases, in particular air inclusions, and / or liquids, in particular diluents.

[0034] In an embodiment, the cold casting mold comprises an organic material, in particular an organic polymer or a plastic with a melting point and / or a decomposition temperature in a temperature range from 40°C to 300°C, in particular from 60°C to 300°C, so that the cold casting mold is plasticizable, in particular at a temperature in a temperature range from 35°C to 300°C, in particular from 50°C to 300°C, and / or is thermally and / or thermochemically decomposable, in particular at a temperature in a temperature range from 200°C to 650°C.

[0035] Dental components such as crowns, bridges, implant components, and / or dentures often require delicate, thin-walled structures. High sintering temperatures are particularly necessary for the production of dental components made of ceramic or metal. To prevent damage to the component due to the thermal expansion of the cold-casting mold, the linear thermal expansion of the cold-casting mold is advantageously at most 10%, more preferably at most 3%, and most preferably at most 0.8% of its original geometry, with the maximum thermal expansion of the cold-casting mold being reached at a temperature of less than or equal to 240°C, more preferably less than or equal to 200°C, further preferably less than or equal to 150°C, and most preferably less than or equal to 100°C.Preferably, the coefficient of thermal expansion (CTE) of the mixing compound can be adjusted to the CTE of the cold casting mold by adjusting the proportions of polyelectrolytes and binders (polymers), taking into account the respective CTE values ​​of the metal, ceramic, or glass-ceramic powder used, so that the cold casting mold and the mixing compound are subject to similar or identical thermal expansion. Additionally or alternatively, the mechanical stability of the mixing compound (in its green state) can be increased by increasing the binder content.

[0036] To achieve the dimensional accuracy required for dental components, even in pressure-filling processes, the cold-casting mold must have a Shore A hardness of at least 15 and / or Shore D hardness of at least 10 and a modulus of elasticity of at least 5 MPa. The walls defining the cavity of the cold-casting mold preferably each have a wall thickness of at least 0.01 mm. Shore hardness is a material property for elastomers and plastics and is defined in the standards DIN EN ISO 868, DIN ISO 7619-1, and ASTM D2240-00. The modulus of elasticity, also known as the tensile modulus or Young's modulus, is determined for plastics, in particular, according to DIN EN ISO 527-1:2019-12.

[0037] An exemplary prototype of a cold casting mold according to the invention, suitable for the production of dental molded parts, was produced using a stereolithography 3D printing process with the following PHYSICAL PROPERTIES: ASTM method Property description Metric Imperial D638M Tensile modulus 2100 MPa 305,000 psi D638M Breaking strength 44.9 MPa 6,500 psi D638M Elongation at break 6.1% 6.1% D790M Flexural strength 74.3 MPa 10,770 psi D790M Bending modulus 2200 MPa 329,000 psi D224 Hardness (Shore D) 85 85 D256A Izod impact strength 0.23 J / cm 0.46 ft lb / in D570-98 Water absorption 0.7% 0.7% D648 HDT @ 0.46 MPa (66 psi) 59° C 138°F D648 HDT @ 1.82 MPa (264 psi) 50° C 122°F

[0038] By using a starting material for the additive manufacturing of the cold casting mold, which forms one or more transparent and / or UV-permeable walls defining the mold cavity, optical monitoring of the mold filling process is possible. For example, the mixing compound or different mixing compounds can be marked with optical markers, especially food coloring. The filling of the cold casting mold can then be automatically monitored with a camera.

[0039] Furthermore, the application possibilities of the cold casting mold can also be extended to light-curing mixing compounds, which are light-cured inside the cold casting mold in a suitably adapted process for the production of molded parts, especially dental molded parts.

[0040] The object of the invention stated at the outset is consequently also achieved by a method for producing molded parts, in particular dental molded parts, from a sinterable mixing compound using a cold casting mold according to the invention and by a method for producing molded parts, in particular dental molded parts, from a light-curing mixing compound using a cold casting mold according to the invention according to one of the preceding embodiments.

[0041] A method according to the invention for producing molded parts, in particular dental molded parts, especially crowns, bridges, dental implant components, prostheses, etc., from a sinterable mixing mass, such as dental ceramic or glass ceramic powders or slurries, dental metal powders or slurries, etc., using the cold casting mold according to the invention, comprises the following process steps: Providing and / or manufacturing the cold casting mold with a cavity and at least one first opening leading into the cavity, as well as at least one second opening leading into the cavity, filling the cavity of the cold casting mold via the at least one first opening with the sinterable mixing compound, and curing and / or solidifying the sinterable mixing compound in the cavity of the cold casting mold.

[0042] During both filling and curing and / or solidification of the mixing compound, any gases and / or liquids contained and / or trapped in the mixing compound are discharged from the cavity through the at least one second opening. Optionally, and following filling, any gases and / or liquids contained and / or trapped in the mixing compound can also escape through the at least one first opening, which remains unlocked throughout the entire process.

[0043] Already during the hardening and / or solidification of the mixing compound, or optionally only after the mixing compound has completely hardened, especially to green body hardness, a Thermal and / or thermochemical decomposition of the cold casting mold is initiated, particularly at temperatures between 200°C and 650°C. Finally, the mixture is sintered to its final hardness, particularly at temperatures between 900°C and 2500°C, until a ready-to-use part, especially a dental prosthesis, is obtained. Optionally, the thermal and / or thermochemical decomposition of the cold casting mold can be continued or terminated during sintering.

[0044] A manufacturing process is also published that uses a cold-casting mold with at least two openings connected to the cavity via a fluid-conducting mechanism. The cavity of the cold-casting mold is filled through one opening (the first), and fluids contained in the mixture, such as thinning agents, or fluids trapped within the mixture, such as air inclusions, are discharged from the mixture or the cavity through at least one other opening (the second). The at least two openings enable the process to cure and / or solidify even mixtures containing binders and / or moist or pasty mixtures, such as slurries or suspensions.

[0045] Preferably, according to a further development of the process, the mixing mass is therefore in the form of a slurry and / or pasty mass and contains a thinning agent, in particular water, wherein the mixing mass hardens in the cavity of the cold casting mold by drying and a liquid component and / or moisture content of the mixing mass is drained out of the cold casting mold, in particular removed from the mixing mass, by means of the at least one or the plurality of second openings.

[0046] In an advantageous process design, the mixing mass comprises a metal powder, in particular a CrCo powder or a ceramic powder, in particular a zirconium oxide powder and / or an aluminum oxide powder or a glass ceramic powder, in particular a lithium disilicate powder and a binder, wherein, in a further development of this process design, the mixing mass hardens to green body hardness in the cavity of the cold casting mold.

[0047] Binder-containing mixtures can be hardened to green compact hardness in the cold casting mold solely by drying, without applying pressure. Therefore, the use of a binder eliminates the need for the costly isostatic pressing process known from the prior art. However, compared to the prior art method, this requires the hardening of the mixture with the cold casting mold open (without a "lid"), whereby fluids are discharged from the mold cavity through at least one second opening and, if necessary, also through at least one first opening.

[0048] Binders are known in many forms from the prior art and consist largely of organic substances such as resins, surfactants, polyelectrolytes, polymers and / or waxes, which result in a comparatively low melting point.

[0049] In order to achieve a gentle removal of the cold casting mold from the mixing mass before debinding takes place or before the binder begins to melt, according to one process variant the temperature resistance and / or heat deflection temperature of the cold casting mold, in particular the melting point and / or the decomposition temperature of the cold casting mold, is below the melting point of the binder and / or below the sintering temperature of the metal powder or the ceramic powder.

[0050] The method envisages the use of a thermally and / or thermochemically decomposable cold casting mold. The thermal and / or thermochemical decomposition of the cold casting mold is preferably carried out in a sintering furnace, wherein the cold casting mold is opened and placed in the sintering furnace together with the mixing mass contained therein. The decomposition of the cold casting mold can be initiated or completed at a temperature in the range of 200°C to 650°C. The respective sintering temperatures of the ceramic powders or metal powders contained in the sinterable mixing masses are in a range between 1200°C and 2500°C, such that the cold casting mold is completely or almost completely thermally and / or thermochemically decomposed by the time the finished molded part, in particular a dental molded part, is obtained, i.e. one sintered to its final hardness.In this way, the cold casting mold can be removed gently and without damaging the molded part without any additional work steps before or during the sintering process.

[0051] An optional process step involves pre-sintering the mixture before the actual sintering, particularly at a temperature in a range of 650°C to 1300°C, in order to remove the binder content before the molded part is compacted to final hardness.

[0052] According to one process variant, the cold casting mold can be decomposed pyrolytically under oxygen-free conditions. Specifically, the cold casting mold, together with the mixing compound it contains, is placed in a sintering furnace, which allows sintering under vacuum and / or a protective atmosphere. This process variant is particularly suitable for the production of metallic dental molded parts, for example, made of a CrCo alloy, to prevent damage to the molded part due to oxidation. However, according to another process variant, decomposition of the cold casting mold under oxygen supply by combustion is also possible, particularly to preserve ceramic dental advantages.

[0053] A method for producing molded parts, in particular dental molded parts, from a light-curing mixture using a cold casting mold according to the invention, comprises the following steps: Providing and / or manufacturing the cold casting mold with a cavity and at least one first opening leading into the cavity, as well as at least one second opening leading into the cavity; filling the cavity of the cold casting mold via the at least one first opening with the light-curing mixing compound; curing and / or solidifying the light-curing mixing compound in the cavity of the cold casting mold. Gases and / or liquids contained and / or trapped in the mixing compound are vented from the cavity via at least one second opening. For the production of molded parts, particularly dental components, from light-curing mixing compounds, it is also intended that fluids contained therein can escape through at least one second opening during filling and / or curing or solidification. Especially when using multi-component materials that must be mixed together during filling, undesirable air inclusions often occur. Even during filling with the mixing compound, such air inclusions can escape through at least one second opening of the cold casting mold.

[0054] Optionally, thermal and / or thermochemical decomposition of the cold casting mold can be omitted. The cold casting mold is separated or detached from the mixing compound along one or more predetermined breaking points to obtain a ready-to-use molded part, particularly a dental component such as a denture. The predetermined breaking points are preferably formed during the manufacturing of the cold casting mold; in particular, they may be wall areas with a thinner wall than the other wall areas. Particularly by blowing in compressed air or using an eccentric tool, the cold casting mold can be "torn open" along the predetermined breaking points after the mixing compound has hardened and / or solidified, thus separating it from the molded part.

[0055] According to an advantageous process design, the mixing mass comprises an organic material, in particular a plastic or a plastic-based composite material, especially a plastic-based hybrid composite material or nanohybrid composite material. Such composites are currently used in dental technology primarily for fillings or temporary restorations. However, nanohybrid composite materials, with a high filler content of fibers or particles and a particle size in the nanometer range, can also, in principle, achieve the material properties required for dental prostheses, such as hardness and density.

[0056] In an advantageous embodiment of the process, the mixing compound hardens in the cavity of the cold casting mold through a chemical reaction, for example, using a two-component binder. The chemical reaction can be initiated by the application of heat and / or the removal of moisture. Particularly preferably, the chemical reaction is triggered by exposure to light, wherein the walls delimiting the cavity of the cold casting mold are transparent and / or UV-permeable, and the cold casting mold is irradiated with a light source, in particular a UV lamp.

[0057] Preferably, the mixing compound is hardened in the cavity of the cold casting mold to the desired final hardness, i.e., the hardness of the finished molded part, before the cold casting mold is removed.

[0058] The following descriptions contain advantageous process variants that are applicable both to the production of molded parts from sinterable mixing compounds and to the production of molded parts from chemically curing, in particular light-curing, mixing compounds. For example, the cold casting mold, and in particular the walls of the cold casting mold that define the cavity, can be coated with a coating agent before being filled with the mixing compound in order to prevent a frictional and / or material-bonded connection between the cold casting mold and the mixing compound.

[0059] It is conceivable to immerse the cold casting mold in a basin containing an organic, oily liquid such as petroleum shortly before or immediately before filling it with the mixing compound, or alternatively to rinse it with an organic, oily liquid such as petroleum. This allows a heat-resistant protective layer to be easily and simply formed between the walls of the cold casting mold that define the cavity and the mixing compound, without closing the first and / or second opening.

[0060] Preferably, the cavity of the cold casting mold is filled under pressure, wherein the internal pressure present in the cavity is lower than the filling pressure with which the mixing mass is supplied to the cavity.

[0061] In practical implementation, two basic variants are conceivable. In a so-called vacuum filling (similarly implemented, for example, in bottle filling systems), a negative pressure compared to the ambient pressure or a vacuum (0.1 mbar to 0.5 mbar) can be created within the cavity, whereby the mixing compound is "sucked" into the cavity. After filling, the vacuum or negative pressure is released, allowing liquids and / or gases to escape from the at least one second opening and / or the at least one first opening. In this first variant, the filling pressure then corresponds to the ambient pressure. In the second variant, the mixing compound can be pressurized, for example using a pump, a screw conveyor, or a simple syringe, with overpressure in a range of, for example,Pressures between 1.5 mbar and 10 bar are injected into the cavity, whereby liquids and gases can escape from at least one secondary opening during filling. A well-known pressure filling method is, for example, injection molding.

[0062] After filling, it is advantageous for the mixing compound to harden in the cavity of the cold casting mold under the influence of heat. The cold casting mold, filled with the mixing compound and opened, is placed in a drying oven, climate chamber, or sintering furnace, and a temperature is maintained within a range of 35°C to 120°C, preferably 50°C to 120°C. If necessary, the humidity can also be adjusted to a desired value. For gentle, uniform, and rapid drying, a humidity level between 1% and a maximum of 50% has proven advantageous.

[0063] The effect of heat and, if necessary, reduced air humidity can accelerate the curing and / or solidification of the mixing compound, for example, in the case of a drying process. In particular, the ambient atmosphere, i.e., in the drying cabinet, climate chamber, or sintering furnace, is dried, which allows moisture and / or liquid contained in the mixing compound to be transported more quickly from the cavity into the environment. This effect can have a significant impact on drying times, especially when cold casting mold walls are designed with a porous and / or hygroscopic surface interspersed with numerous secondary openings such as pores and / or capillaries.

[0064] According to one process option, the cold casting mold is plasticized after filling with the mixing compound and preferably also after its hardening in order to facilitate the detachment of the walls defining the cavity from the mixing compound contained therein. The cold casting mold filled with the mixing compound is placed in a drying cabinet or climate cabinet or a sintering furnace and a temperature is set in a temperature range of 35°C to 300°C, preferably 45°C to 180°C. The material properties of organic materials or plastics can be utilized here. Before the melting point of the cold casting mold is reached, the organic material, in particular the plastic, begins to soften, whereby the cold casting mold can be plasticized or plastically deformed. By specifically blowing in compressed air, the soft, deformable cold casting mold can be released from the preferably hardened mixing compound.

[0065] Particularly fast and even filling can be achieved, for example, by one variant of the process, in which the cavity of the cold casting mold is filled with the mixing compound through several initial openings.

[0066] For example, mixing compounds consisting of two or more components can be filled into the cavity of the cold casting mold via two or more corresponding first openings in order to prevent premature (light-induced) hardening and / or solidification during filling.

[0067] In a further development of this design variant, the cavity of the cold casting mold is filled via the several first openings with respective mixing masses containing additives for coloring and / or for generating opacity to produce a molded part, in particular a dental molded part with areas of differing coloring and / or opacity.

[0068] In this way, the natural appearance of a tooth can be replicated. The various mixing compounds can contain different additives that, in the finished molded part, result in a color matching the standard shade guide of Vita, Bad Säckingen, A1 to A4, B1 to B4, C1 to C4, and D1 to D4. A multitude of suitable additives are known from the prior art. Examples of suitable coloring elements are Fe, Mn, Cr, Ni, Co, Pr, Ce, Eu, Gd, Nd, Yb, Tb, Er, and Bi.

[0069] Finally, according to an advantageous process variant, the cold casting mold is produced according to one of the process variants of the manufacturing process for a cold casting mold described at the beginning.

[0070] Further details, features, combinations of features, advantages, and effects based on the invention will become apparent from the following description of preferred embodiments of the invention and the drawings. These show in Fig. 1 a schematic perspective view of a first embodiment of a cold casting mold according to the invention with a filling channel and a compensation volume, Fig. 2 a sectional view of the cold casting mold made of Figure 1Fig. 3 a schematic perspective view of a second embodiment of a cold casting mold according to the invention with one filling channel, Fig. 4 a sectional view of a third embodiment of a cold casting mold according to the invention with a total of five filling channels, Fig. 5 a schematic perspective view of a fifth embodiment of a cold casting mold according to the invention with five filling channels and a mixing agent, Fig. 6 a sectional view of the cold casting mold made of Figure 5 with attached filling means, Fig. 7 a schematic side view of a fourth embodiment of a cold casting mold according to the invention with wall reinforcements and predetermined breaking points, Fig. 8 a schematic perspective view of a molded part which was produced with a cold casting mold according to the invention, Fig. 9 a sectional view of the cold casting mold made of Figure 4, which is filled with different mixing compounds, Fig. 10 a schematic representation of the cavity of the cold casting mold filled with different mixing compounds made of Figure 9 , Fig. 11 a sectional view of the cavity of the cold casting mold filled with different mixing masses made of Figure 9 , Fig. 12 a flow diagram of an exemplary sequence of the method for producing a molded part, in particular a dental molded part, Fig. 13 a schematic sectional view of the cold casting mold from the Figures 1 and 2 , which is filled electrophoretically with mixing compound, Fig. 14 a schematic sectional view of the cold casting mold made from the Figures 1 and 2 , which is filled with mixing compound under pressure and Fig. 15 a schematic representation of a cold casting mold whose cavity corresponds to the shape of a dental prosthesis.

[0071] The figures are merely illustrative and serve only to explain the invention. The same elements are identified by the same reference symbols and are therefore generally described only once.

[0072] The Figures 1 and 2 Figures 1 and 2 each show a first embodiment of a cold casting mold 100 according to the invention, in a schematic perspective view and a sectional view, respectively. The cold casting mold 100 is shown here by way of example in the form of a test specimen, the cavity 110 of which has geometric properties typical for dental components 210, resulting in wall thicknesses of the component 210 in a range of 0.30 mm to 10 mm. The cavity 110 of the cold casting mold 100 is bounded by the outer walls 121 and the inner walls 122 of the cold casting mold 100, so that the finished component 210, e.g., a crown, has an inner cavity 211 (see Figure 1). Figure 8) has a shape, for example, corresponding to that of an abutment, allowing the crown to be placed on the abutment. The inner walls 122 form a cylindrical or frustoconical shape for this purpose. A first opening 111 leads into the cavity 110 and penetrates one of the outer walls 121, which is occlusal with respect to the dental component 210. The cavity 110 is filled with the mixing compound 200 via the first opening 111. The inner walls 122 are perforated with a multitude of second openings 112, which, for example, allow fluids 205, 207 and / or air inclusions 208 contained in the mixing compound 200 to escape during filling. After filling, fluids 205, 207, 208 can optionally also escape via the first opening 111. The multitude of second openings 112 can, as shown here by way of example, penetrate an inner surface of the cavity 110 in a sieve-like manner.Alternatively, the multitude of second openings 112 could be designed in the form of pores and / or capillaries and form a porous and / or hygroscopic surface.

[0073] A fluid-conducting filling channel 130 with a compensation volume 131 is connected to the first opening 111. Filling media 400, such as injection syringes 420, in particular low-pressure injection syringes (see figure), can be connected to the filling channel 130. Figure 15 ) or supply lines, such as hoses 410 (see Figure 6) to facilitate the filling of the cavity 110 with mixing compound 200. The compensation volume 131 serves as a type of reservoir for the mixing compound 200, so that the volume loss of fluids 205, 207, 208 escaping through the second openings 112 can be compensated by the mixing compound 200 stored in the compensation volume 131. In the illustrated embodiment, the cold casting mold 100 is manufactured in one piece with the filling channel 130 and the compensation volume 131.

[0074] In the Figure 3 Figure 1 shows a schematic perspective view of a second embodiment of a cold casting mold 100 according to the invention. The cold casting mold 100 corresponds to the one described in the Figures 1 and 2shown first embodiment, with the exception that the filling channel 130 is formed without the (optional) compensating volume 131 and a channel-like, second opening 112 opens integrally into the occlusal, outer wall 121. The filling channel 130 can be realized either in one piece or as an additional part of the cold casting mold (100) and opens into the cavity (110) with its first opening 111. In this variant, the first opening 111 passes concentrically through the second opening 112. If necessary, a separate compensating volume 131, in particular as a component of a filling means 400, can be connected to the filling channel 130.

[0075] A sectional view of a third embodiment of a cold casting mold 100 according to the invention with a total of five filling channels 130 can be found in the Figure 4The filling channels 130 each open into the cavity 100 via first openings 111 that penetrate the occlusal, outer wall 121 of the cold casting mold 100. Each of the filling channels 130 is fluid-conductingly connected to an associated compensation volume 131. The cold casting mold 100 can be filled with the same or different mixing material 200 via one or more of the filling channels 130. Filling channels 130 not used for filling then function as secondary openings 112 and serve to discharge fluids 205, 207 and / or air inclusions 208 contained in the mixing material 200. In particular, when all filling channels 130 are used, rapid and especially uniform filling of the cavity 110 of the cold casting mold 100 is possible.

[0076] The Figure 5A schematic perspective view of a fourth exemplary embodiment of a cold casting mold 100 according to the invention can be seen. The cold casting mold 100 has a total of five filling channels 130, which open into the cavity 110 via first openings 111, passing through the occlusal, outer wall 121. One of the filling channels 130 is provided with a conveying and / or mixing means 132, here in the form of a screw conveyor. This filling channel 130 is designed with a larger cross-sectional area, in particular a larger diameter, than the four remaining filling channels 130. According to the illustration shown, the conveying and / or mixing means 132 is inserted as an additional component into the filling channel 130, which is preferably designed integrally with the cold casting mold 100.Particularly advantageously, the conveying and / or mixing agent 132 can be additively formed directly inside the filling channel 130 during the production of the cold casting mold 100.

[0077] In the Figure 6 is the cold casting mold according to the Figure 5in a sectional view with additional, respective compensation volumes 131, which are fluidically connected to the respective filling channels 130. A filling means 400 is connected to the filling channel 130 containing the conveying and / or mixing means 132 via two hoses 420. Mixing compound 200 is supplied to the cold casting mold 100 via the hoses 420. The exemplary embodiment shown here is particularly well suited for mixing compounds 200 which are composed of, for example, two components. The components can initially be fed separately to the filling channel 130 via the two hoses 420 and mixed with one another there by means of the conveying and / or mixing means 132 before the mixed mixing compound 200 enters the cavity 110 through the first opening 111.

[0078] A fifth embodiment of a cold casting mold 100 according to the invention can be described as follows: Figure 7can be seen in a schematic side view. Along the outer walls 121 defining the cavity 110, the cold casting mold 100 is formed integrally with two wall reinforcements or projections 123, each designed in the manner of a flange. The section of the corresponding outer wall 121 located between the wall reinforcements 123 is manufactured with a thinner wall thickness than the wall reinforcements 123 and therefore serves as a predetermined breaking point 124. By inserting an eccentric tool 125 between the two wall reinforcements 123, the cold casting mold 100 can be "levered open" along the predetermined breaking point 124 in order to release the cold casting mold 100 from the mixing compound 200 that has hardened therein.

[0079] The mixing compound 200, hardened to the final hardness required for dental molded parts 210, is the Figure 8as a finished molded part 210, which was produced with the cold casting mold 100 designed as a test specimen. The molded part 210 has wall thicknesses in a range of 0.3 mm to 10 mm. A lower, apical section of the molded part 210 is formed with a recess 211, the shape of which corresponds to the shape of an abutment for placing a dental molded part 210, for example a crown. Due to the plurality of second openings 112, which penetrate the inner walls 122 of the cold casting mold 100 in a sieve-like structure (see Figure 2 The inward-facing walls of the recess 211 are provided with a nub-like surface 212. The nub-like surface 212 improves the retention between the dental component 210, for example a crown, and, for example, the abutment.

[0080] In the Figure 9 is the cold casting mold 100 from the Figure 4The cavity 110 of the cold casting mold 100 is shown in a sectional view. Here, the cavity 110 of the cold casting mold 100 is filled with different mixing compounds 201, 202, 203, and 204 via a filling medium 400. The mixing compounds 201, 202, 203, and 204 each contain additives suitable for coloring and / or creating opacity in the finished molded part 210. Each of the mixing compounds 201, 202, 203, and 204 is preferably filled into the cavity 110 via its own filling channel 130 and the first opening 111 adjoining it.

[0081] The Figures 10 and 11Each figure shows a schematic cross-sectional view of a cavity 110 filled with different mixing compounds 201, 202, 203, and 204. For example, the lower, apical section of the cavity 110 can be filled with a third mixing compound 203, two outer, occlusal sections with a first mixing compound 201 and a fourth mixing compound 204 respectively, and an intermediate occlusal section with a second mixing compound 202. After curing and / or hardening to its final strength, the finished dental component 210 then exhibits areas or sections of different colors or tooth shades and / or different opacities or transparencies.

[0082] The Figure 12shows a flow diagram of an exemplary sequence of the method for producing a dental molded part 210. First, a cold casting mold 100 is provided or produced (1). The cold casting mold 100 is constructed using an additive material construction process, for example, with a 3D printer, wherein the cold casting mold 100 has at least one first opening 111 and at least one second opening 112. A thermally and / or thermochemically decomposable plastic is preferably used as the starting material 150. Optionally, the cold casting mold 100 can be formed with one or more predetermined breaking points 124 during production. Optionally, the cold casting mold 100 can be coated with a coating agent 220 (1.1) before it is filled with the mixing compound 200. Petroleum, for example, is suitable as the coating agent 220, wherein the cold casting mold 100 is preferably immersed in a basin containing petroleum.The cold casting mold 100 is then filled with the mixing compound 200 (2). Depending on the desired molded part 210, the mixing compound 200 comprises a ceramic, a metallic, or a plastic powder 209, which is suitable for the production of dental molded parts. The respective powder 209 is preferably mixed with a diluent 205, for example water or an organic solvent, to form a slip or a pasty mass, mixed with a binder 206, and conditioned before use. The mixing compound 200 is filled into the cavity 110 of the cold casting mold 100 via the at least one first opening 111. Already during filling, fluids 207 contained in the mixing compound 200, in particular the diluent 205 or air inclusions 208, can escape via the at least one second opening 112. After filling, the mixing compound 200 hardens inside the cold casting mold 100, more precisely in its cavity 110 (3).To accelerate curing, the cold casting mold 100 is placed, for example, in a drying cabinet or climate cabinet to adjust the desired ambient humidity and is subjected to heat 230 so that the liquid components of the mixing compound 200 dry or evaporate more quickly. Fluids 207, diluents 205, or air pockets 208 can continue to escape through the at least one second opening 112 and optionally also through the at least one first opening 111. For the production of dental molded parts 210 made of plastic, the cold casting mold 100 is transparent and is exposed to light 231, in particular UV light. With dental plastic, curing in the cold casting mold 100 until the final hardness is achieved is possible.For the production of ceramic or metallic dental components 210, curing in the cold casting mold 100 is preferably carried out until the green body hardness is reached. The stability of the green body can be achieved by the binders 206 used.

[0083] After curing, the cold mold 100 can optionally undergo plasticization (3.1). For this purpose, the cold mold 100, together with the cured mixing compound 200 contained within it, is placed in a sintering furnace, and a temperature in the range of 35°C to 300°C, particularly 50°C to 300°C, is set inside the sintering furnace. The plastic of the cold mold 100 softens and can, for example, be "inflated" by blowing in compressed air 232 and separated from the mixing compound 200. In the case of a dental plastic mold 210, the cold mold 100 is opened (4.B) by applying mechanical force along one or more predetermined breaking points 124 formed during production, and the finished dental mold 210 is removed.

[0084] For the production of ceramic or metallic dental components 210, the cold-casting mold 100 is thermally or thermochemically decomposed (4.A) before or while the mixing compound 200 hardens to its final strength. For this purpose, the cold-casting mold 100, together with the mixing compound 200 contained therein, is placed in a sintering furnace, and thermal decomposition or pyrolysis under exclusion of oxygen, or thermochemical decomposition or combustion with oxygen, is initiated at a temperature in the range of 200°C to 650°C, at which point the starting material 150 is completely or almost completely dissolved. At a temperature in the range of 650°C to 1300°C, the mixing compound 200 can optionally be pre-sintered (5.1), whereby the binder 206 evaporates.During the final or sealing sintering (5), the mixing compound 200 is compacted to its final hardness at a temperature in a range of 900°C to 2500°C and can be removed from the sintering furnace as a finished dental component 210. Any remaining fragments of the cold casting mold 100 that are not yet completely decomposed are also decomposed during the pre- or final sintering.

[0085] The Figure 13 shows a schematic representation of a possible filling of the cold casting mold 100. Figure 2by means of electrophoresis, in particular electrofiltration. The filling material 400 is designed here in the form of an electrophoretic device. For electrofiltration, it is necessary that the mixing material 200 is conductive, e.g., comprising a metallic powder, whereas the cold-casting mold 100 is optionally made of conductive polymers, either as an insulator, e.g., of plastic, or also conductive. The at least one first opening 111 of the cold-casting mold 100 is electrically connected via the mixing material 200 to a cathode 430 of the filling material 400. The plurality of second openings 112 are also electrically connected via the conductive mixing material 200 to an anode 431 of the filling material 400. By applying a voltage via a voltage source 432, an electric current can be generated, which causes particle transport from the cathode 430 to the anode 431.Experiments have shown that approximately 80% of the diluent 205 escapes from the mixing compound 200 during the electrophoretic filling of the cold casting mold 100, resulting in a significantly shortened process time. The remaining moisture content in the mixing compound 200 escapes, as previously described in detail, through the multiple secondary openings 112, particularly through the porous and / or hygroscopic surfaces formed by these openings, until the mixing compound 200 hardens and / or solidifies. Preferably, the first opening 111 located in the region of the cathode 430, or a subsequent filling channel 130, is provided with a tubular siphon 433, which allows the hydrogen formed in aqueous mixing compounds 200 to escape, thus ensuring the homogeneity of the mixing compound 200.

[0086] The Figure 14 shows a schematic sectional view of the cold casting mold 100 from the Figures 1 and 2 The mold 100 is pneumatically filled with mixing compound 200 under pressure. This method is particularly well suited for the homogeneous filling of powdered mixing compounds 200, but also for slurries or pasty masses. For filling, the cold casting mold 100, or rather its cavity 110, is used in the manner of a vacuum cleaner bag, whereby the pressure within the cavity 110 is lower than the ambient pressure. This can be achieved either by supplying the mixing compound 200 to the cavity 110 via a pressurized conveying line 440 of the filling device 400, which is designed here as a pressure device. The introduction of the mixing compound 200 into the conveying line 440 can be achieved using rotary valves, pressure vessels, and / or pressure conveying systems.

[0087] Alternatively or additionally, a vacuum can be generated in the cavity 110 of the cold casting mold 100, thereby enabling vacuum conveying or suction conveying of the mixing compound 200. A vacuum generator 441 is used to create a vacuum, either centrally or decentrally, to draw in the mixing compound 200 through the at least one first opening 111 and transport it into the cavity 110 of the cold casting mold 100. The mixing compound 200 is retained within the cavity 110 by the multiple secondary openings 112 or the intervening wall sections. The conveying air 442 used to transport the mixing compound 200 passes through the multiple secondary openings 112 and is supplied from the environment via a particle filter 443. The filling process is controlled by a bypass channel 444, which is fluidly connected to the filling channel 130.

[0088] The Figure 15Finally, Figure 1 shows an exemplary embodiment of the invention, in which the cold-casting mold 100 has a cavity 110 corresponding to the geometry of a dental component 210. A print nozzle 310 of a 3D printer 300 is also schematically indicated in the figure, by means of which the cold-casting mold 100 is additively built up in one piece from the starting material 150. The cold-casting mold 100 comprises a first opening 111, which is fluidly connected to a filling channel 130 via a valve-controlled compensation volume 131. The cavity 110 is filled with the mixing compound 200 via the filling channel 130 using a filling medium 400, here by way of example an injection syringe 420. Fluids 207 contained in the mixing mass 200 or air inclusions 208 formed during filling are discharged from the cavity 110 via a multitude of second openings 112.The second openings 112 are formed here as capillaries or pores in the outer walls 121 and are therefore not visible to the naked eye. The multitude of second openings 112 creates a porous or hygroscopic surface that conducts fluids 207 or moisture contained in the mixing compound 200 from the cavity into the external environment. List of reference symbols

[0089] 100 Cold casting mold 110 Cavity or tool shape 111 First opening 112 Second opening 120 Wall 121 Outer wall 122 Inner wall 123 Wall reinforcement / wall projection 124 Break point 125 Eccentric tool 130 Filling channel 131 Equalizing volume 132 Conveying and / or mixing medium 140 Support structure 150 Starting material 200 Mixing compound 201, 202, 203, 204 Mixing compound with additives 205 Thinner 206 Binder 207 Fluids 208 Air inclusions 209 Powder 210 Molded part 211 Recess 220 Coating agent 230 Heat / humidity 231 Light 232 Compressed air 300 3D printer 310 Print nozzle 400 Filling agent 410 Hose 420 Injection syringe, especially low-pressure injection syringe 430 Cathode 431 Anode 432 Power source 433 Tubular siphon 440 Conveyor line 441 Vacuum generator 442 Conveying air 443 Particle filter 444 Bypass channel Process steps:

[0090] 1Providing and / or producing a cold casting mold 1.1Coating the cold casting mold 2Filling the cold casting mold with mixing compound 3Curing and / or solidifying the mixing compound in the cold casting mold 3.1Plasticizing the cold casting mold 4.Thermal or thermochemical decomposition of the cold casting mold 4.Mechanical separation of the cold casting mold and mixing compound 5.1Pre-sintering 5Sintering

Claims

1. A method for producing a cold casting mold (100) for producing molded parts (210), in particular dental molded parts (210), from a mixing compound (200), wherein the cold casting mold (100), having a cavity (110) that corresponds geometrically to the molded part (210), in particular the dental molded part (210), is additively constructed from a starting material (150) by means of an additive material construction method, in particular a 3D printing method using a 3D printer (300), on the basis of a digital data set in particular based on a three-dimensional model of the oral cavity of a patient and with at least one first opening (111) that opens into the cavity (110) for filling with the mixing compound (200), characterized in that the cold casting mold (100) is additively constructed having at least one second opening (112) opening into the cavity (110) and / or leading out of the cavity (110) for discharging gases, in particular air inclusions (208), and / or liquids, in particular diluents (205).

2. The method as claimed in claim 1, characterized in that at least one wall (120) of the cold casting mold (100) delimiting the cavity (110) is additively constructed completely or in regions having a plurality of second openings (112) opening into the cavity (110) and penetrating this wall (120) for discharging gases, in particular air inclusions (208) and / or liquids, in particular diluents (205).

3. The method as claimed in claim 2, characterized in that the plurality of second openings (112) are formed in the manner of pores and / or capillaries penetrating the wall (120), so that the wall (120) has porous and / or hygroscopic properties completely or in regions.

4. The method as claimed in any one of the preceding claims, characterized in that the cold casting mold (100) is additively constructed having a filling channel (130) adjoining the at least one first opening (111) in a fluid-conducting manner, wherein the filling channel (130) is connected in a fluid-conducting manner to at least one compensating volume (131) for storing mixing compound (200).

5. The method as claimed in any one of the preceding claims, characterized in that an organic material, in particular an organic wax and / or a polymer and / or a plastic, is used as the starting material (150) for additively constructing the cold casting mold (100), so that the cold casting mold (100) can be plasticized and / or thermally and / or thermochemically decomposed.

6. The method as claimed in any one of the preceding claims, characterized in that at least one wall (120) delimiting the cavity (110) of the cold casting mold (100) is additively constructed having a predetermined breaking point (124), in particular having a reduced wall thickness in regions.

7. A cold casting mold (100) for producing molded parts (210), in particular dental molded parts (210) from a mixing compound (200), which cold casting mold (100) is integrally produced by means of an additive material construction method, in particular as claimed in any one of the preceding claims, wherein the cold casting mold (100) has a cavity (110) that corresponds geometrically to the molded parts (210), in particular dental molded parts (120) and is created on the basis of a digital data set, in particular based on a three-dimensional model of the oral cavity of a patient, and at least one first opening (111) opening into the cavity (110) for filling with the mixing compound (200), characterized in that the cold casting mold (100) has at least one second opening (112) opening into the cavity (110) for discharging gases, in particular air inclusions (208), and / or liquids, in particular diluents (205).