Method for forming a glass product, apparatus for carrying out the method, and use of a molten metal for carrying out the method

Abstract

The present invention relates to a method for forming a glass product (10), in particular a three-dimensionally shaped flat glass product, in which the following steps are carried out: Between a forming plunger (20) and a liquid metal (30), in particular a melt of tin, glass (10), for example a flat glass sheet of uniform thickness, a flat glass sheet of non-uniform thickness, or a preformed flat glass sheet blank or a liquid two-dimensionally spread flat molding of glass is placed, and at least one portion formed from the flat molding of glass (10) is melted at a temperature of 10 Pas to 10 Pas. 6.5 Pas range, preferably 10 Pas to 10 4 Pas range, particularly preferably 10 Pas to 10 3 Tempering to the forming temperature of the glass having a viscosity in the range of 10 Pas, forming the flat molded body of glass (10) by pressing on the one hand by the forming plunger (20) and on the other hand by the molten metal (30) by pressing on both sides and / or by sucking and fitting the flat molded body of glass (10) onto the forming plunger (20) so that the surfaces of the forming plunger (20) and the molten metal (30) approach each other, forming the flat molded body of glass (10) by at least one linear motion, for example by a linear motor or a servo motor, forming the flat molded body of glass (10) by pressing the flat molded body of glass (10) on the other hand by pressing on both sides and / or by sucking and fitting the flat molded body of glass (10) onto the forming plunger (20) so that the surfaces of the forming plunger (20) and the molten metal (30) approach each other, forming the flat molded body of glass (10) by at least one linear motion, for example by a linear motor or a servo motor, forming the flat molded body of glass (10) by pressing the flat molded body of glass (10) against the glass 10. 7 cooling to a handling temperature below the molding temperature having a viscosity of 10 Pa or more, and demolding the cooled flat molding (10), as well as an apparatus for carrying out this method and the use of molten metal for carrying out this method.

Description

[Technical field]

[0001] The invention relates to a method for forming a glass product, in particular a three-dimensional shaped flat glass product, according to the preamble of claim 1, to an apparatus for producing a glass product according to the preamble of claim 8 and to the use of molten metal for producing a glass product according to the preamble of claim 15. [Background technology]

[0002] Methods for forming glass products, in particular three-dimensional shaped flat glass products, such as mobile phones, tablet covers or car windows, have been known for a long time and are mostly based on the fact that a flat glass blank is pressed and / or ground into a desired shape. In the pressing process, a plunger tool is used which has a plunger and a counter plunger, whereby the plunger and the counter plunger are formed in a complementary manner, i.e., for example, concave and convex, respectively, with the shape of the three-dimensional shaped flat glass product to be produced.

[0003] One problem with this manufacturing method is that during the pressing process, both the plunger and the counter plunger inevitably come into contact with the glass product being pressed, which is detrimental to the quality of the pressed glass surface. The optimization of the quality of the glass surface can actually be improved by using a specific suitable glass contact material on the contact surface of the pressing tool. However, post-treatment of each glass surface is usually still required, especially when high quality of each pressed surface is required.

[0004] For the molding and forming of glass, mainly casting alloys, steel alloys, or chrome coatings on steel alloys are used, which, when exceeding the critical temperature, glass adheres in a solid form. Therefore, the molds are designed to maintain a temperature range of 500°C or less, but the molding of glass is performed at temperatures between 10 Pas and 10 6 Pas (10 Pa s to 10 6 Since it is performed at a viscosity of 1 Pa·s, it is performed in the temperature range of 800°C to 1500°C.

[0005] As a result, the temperature gradient of the glass and the glass-contacting materials leads to a temperature gradient within each formed glass part. The forming process is therefore time-limited by the different thermal expansion of the glass and the glass-contacting materials in different temperature ranges. In this technical field, this time-limitation of the forming process should be, among other things, as follows: · Avoid overheating the mold, which cannot dissipate heat from the glass quickly enough and heats up beyond the critical bonding temperature. At high temperatures, glass shrinks faster, which can cause the glass to shrink onto the mold parts that form the internal contour of the workpiece, i.e., the protrusions of the plunger, making it difficult to separate the glass from the mold. The surface is not reheated by the infrared rays accumulated inside the glass, which prevents the glass from equalizing the temperature gradient within the part during the molding process, resulting in surface cracks and deformation due to distortion. Summary of the Invention [Problem to be solved by the invention]

[0006] In this technical field, this leads to very complicated and difficult process control, which is nevertheless detrimental in terms of the quality of the glass obtained.

[0007] As mentioned above, a further possibility for the production of three-dimensional shaped flat glass products is to grind a glass blank by ablation until this blank assumes the desired three-dimensional shape. However, this process also has disadvantages, being time-consuming and, moreover, laborious and difficult to implement, especially when high quality of the respective glass surface is required.

[0008] The present invention aims to provide a method for manufacturing three-dimensionally molded flat glass products, which can produce high-precision flat glass products that achieve high quality of the glass surface while minimizing the need for post-processing, and an apparatus for carrying out the manufacturing method. [Means for solving the problem]

[0009] This object is solved by a method according to claim 1, by a device according to claim 8 and by a use according to claim 15.

[0010] In particular, this object is solved by a method for forming a glass product, in particular a three-dimensional shaped flat glass product, in which the following steps are carried out: a) placing a flat molding of glass, for example a flat glass sheet of uniform thickness, a flat glass sheet of non-uniform thickness, or a preformed flat glass sheet blank, or a liquid two-dimensional diffuse glass, between a forming plunger and a molten metal, i.e. a liquid metal, in particular molten tin, b) The flat glass molded product is subjected to a pressure of 10 Pas to 10 6.5 Pas range, preferably 10 Pas to 10 4 Pas range, particularly preferably 10 Pas to 10 3 Tempering to the forming temperature of glasses with viscosities in the range of Pas, c) forming a flat shape of glass by moving the surfaces of the forming plunger and the molten metal closer to each other so that the flat shape of glass is formed by pressure on one side by the forming plunger and on the other side by the molten metal, by pressure on both sides and / or by sucking the flat shape of glass on the forming plunger to fit; d) The flat molded glass is subjected to a process in which the viscosity of the glass is ≧10 7 Pas(10 7 Cool to a handling temperature below the molding temperature (Pas or higher), e) The cooled flat part is demolded.

[0011] The essence of the invention is that the method of the invention is carried out as a pressing process, even though it uses only a forming plunger in solid, hard form and a liquid molten metal as a counter plunger. According to the invention, it is preferable to use liquid tin as the liquid metal, since tin is very inert to glass and can produce glass surfaces with very high surface quality. Furthermore, the tin bath with liquid tin can be heated to high temperatures that allow the forming of the glass.

[0012] In the process according to the invention, a flat shape of glass is introduced into a forming space arranged between a volume or container for receiving molten metal, such as a metal bath, and a forming plunger. The flat shape of glass, i.e. the glass blank, is subsequently tempered to the forming temperature.

[0013] In this context it should be noted that the volume or container for receiving the molten metal may already be filled with molten metal during the introduction of the flat molding of glass into the molding space.

[0014] However, according to another embodiment of the invention, it is also possible to introduce the molten metal into the volume or vessel provided for it only after the flat molding of glass has been introduced into the molding space.

[0015] According to yet another embodiment, it is also possible that molten metal is already present in the volume or container of molten glass when the flat molding of glass is introduced, but that a flattening of the surface of the molten metal is then carried out, in which case it is possible to raise the level of the molten metal, for example by raising the metal bath and / or by adding more molten metal, or, if necessary, to lower the level of the molten metal, for example by removing the molten metal from the volume or container.

[0016] In the context of the present invention, the forming temperature of the glass is 10 Pas to 10 6.5 Pas range, preferably 10 Pas to 10 4 Pas range, particularly preferably 10 Pas to 103 It is understood that the temperature at which the glass blank has a viscosity in the range of Pas. In an advantageous embodiment, a glass blank of flat glass having a viscosity in the indicated range can be formed into a desired three-dimensional shape to produce a three-dimensionally formed flat glass product by the method according to the invention.

[0017] After the glass blank, i.e., a flat piece of glass, reaches the glass forming temperature, the forming plunger and molten metal are moved toward one another and the compression of the glass blank three-dimensionally forms the flat piece of glass into the desired three-dimensional shaped glass product.

[0018] According to the present invention, a preformed glass blank can be used as a starting glass body or as a starting flat molding, and is formed as a flat glass sheet of uniform thickness, or as a non-uniform thickness or preformed flat glass sheet blank, depending on the desired three-dimensional glass product to be formed.

[0019] Additionally, in accordance with the present invention, a liquid glass may be used as the starting glass, which is introduced between the forming plunger and the molten metal and formed as the forming plunger and the molten metal move closer to each other.

[0020] According to one embodiment of the present invention, during the actual forming of the glass blank into the desired three-dimensional shaped flat glass sheet, as the forming plunger and molten metal move toward each other, the three-dimensional shape contour of the forming plunger is forced into the softened flat glass blank, so that the side of the flat glass blank opposite the forming plunger is forced into the molten metal as the counter plunger.

[0021] According to the invention, the molten metal acts as a counter plunger for the forming plunger, whereby it conforms to the softened flat glass blank and, in interaction with its surface tension and its water pressure, presses the softened flat glass blank homogeneously and uniformly against the three-dimensional contour of the forming plunger.

[0022] The movement of the forming plunger and the molten metal towards each other can be affected in different ways.

[0023] According to one embodiment of the present invention, the molten metal is preferably below the forming plunger, which allows both the level of the molten metal to rise as the molten metal and forming plunger move toward each other, and simultaneously lower the forming plunger if necessary.

[0024] In order to prevent the forming plunger or the softened flat glass product guided by the forming plunger from being pushed out or pushed too far into the molten metal when the molten metal and the forming plunger move together or when forming the desired three-dimensional shaped flat glass product, the pressure that builds up during the forming process is precisely monitored on the one hand and the movement of the molten metal bath and the forming plunger towards each other is precisely controlled on the other hand. Furthermore, the forming plunger is moved in the desired way in a guide that precisely surrounds and guides the forming plunger, whereby the guide closes the volume located to the side of the forming plunger in a particularly sealing manner and ensures that during the immersion of the flat glass product and the forming plunger in the molten metal, the liquid level of the molten metal rises at most to the lower surface of the guide. Further immersion of the respective forming plunger of the softened flat glass product guided by the forming plunger into the molten metal leads to an immediately measurable pressure rise in the forming plunger and the guide on the one hand and in the metal bath on the other hand.

[0025] Similarly, a pressure rise occurs when the softened flat glass product is pressed uniformly over its entire surface against and fits against the contours of the forming plunger. In this condition, no further deformation of the flat glass product occurs, so as the molten metal and forming plunger move further toward each other, a clearly measurable pressure rise occurs, indicating the end of the forming process.

[0026] Because the pressure built up in the molten metal during the pressing process is uniform throughout the molten metal, the process of the present invention avoids stresses in the finished flat glass product that occur in conventional glass pressings because the process provides a uniform pressing of the soft flat glass blank against the three-dimensional mold contour of the forming plunger over the entire surface of the flat glass blank.

[0027] According to another embodiment of the invention, the forming plunger can have an opening that allows for the application of either overpressure or underpressure to the flat body of glass adjacent the forming plunger during the forming operation, as desired, depending on the operating conditions.

[0028] Such a forming plunger has an opening for applying an overpressure to the flat body of glass, thereby also enabling the forming of a flat glass body according to the invention to be carried out in that the metal bath on the one hand and the forming plunger on the other hand approach each other and the overpressure applied via the forming plunger sucks in the flat body of glass as soon as the distance between the flat body of glass and the forming plunger falls below a prescribed distance depending on the applied overpressure.

[0029] In this way, when the flat body of glass and the forming plunger are sufficiently close, shaping of the flat body of glass tempered to the forming temperature according to the invention can occur in that the forming plunger sucks the flat body of tempered glass so that the flat body of tempered glass exactly conforms to the contour of the forming plunger as defined by the forming plunger.

[0030] In such a forming process according to the invention, the tempered flat body of glass can be lifted off the surface of the metal bath by the suction force of the forming plunger. According to the invention, a related advantage is that, by such lifting, the flat body of glass, which was initially placed on the liquid metal surface, is removed from the hot liquid metal surface, which is substantially at the forming temperature, and, after the glass is conformed to it by the low pressure applied by the forming plunger, by contact with the cooled forming plunger, it is immediately or at least very rapidly cooled and solidified in the desired form predetermined by the forming plunger. The cooling of the glass to a viscosity at which the flat body of glass is sufficiently dimensionally stable so that it can be handled for further processing is carried out by contact of the flat body of glass, which is initially at the forming temperature, with the cooled forming plunger, which dissipates the heat of the flat body of glass in the course of contact with the flat body of glass. According to the invention, the forming plunger of glass is tempered to a temperature that allows the forming of the flat body of glass, but is sufficiently low so that no adhesion of the flat body of glass to the forming plunger occurs, so that the formed flat body of glass can be peeled off and / or removed from the forming plunger, in particular immediately, after forming.

[0031] According to yet another embodiment of the invention, the level of the liquid metal bath can be further raised by the forming plunger during the suction process of the flat body of glass tempered to the forming temperature, which can be achieved by raising the metal bath itself or by raising only the level of the liquid metal in the bath by further addition of liquid metal. Such a rise in the liquid metal level can be continued until, on the one hand, the flat body of glass fits into the forming plunger and, on the other hand, it is pressed against the forming plunger by the liquid metal. Such an embodiment has the advantage that the flat body of glass initially tempered to the forming temperature can be further heated or cooled in a targeted manner by temperature control of the metal bath, while, according to the invention, the metal bath remains completely liquid.

[0032] According to the invention, further heating or sustained tempering of the flat body of glass at least to the forming temperature or the relevant viscosity of the flat body of glass depending on the type of glass is particularly advantageous, for example, when forming the flat body of glass into a formed body having an undercut. In such a case, according to the invention, the fully formed glass cooled to the handling temperature can be non-destructively demolded by using a multi-piece forming plunger.

[0033] In any case, the flat body of glass in contact with the forming plunger can be cooled in a particularly targeted and temperature-controlled manner by contacting the liquid metal, which itself cools, thereby extracting heat in a targeted manner from the flat body of glass.

[0034] To release the flat body of formed glass that has been cooled to a handling temperature, overpressure can also be applied through an opening in the forming plunger, which causes and / or facilitates the release of the cooled flat body of glass from the forming plunger.

[0035] According to the invention, the introduction of the glass blank into the forming space can be carried out either by a holding device and / or a support device for flat moldings of glass, which is designed, for example, in the form of a gripper or a lance, holds the glass blank and in particular moves it into the forming space between the molten metal and the forming plunger.

[0036] Alternatively, the introduction of the glass blank into the forming space can be effected by the forming plunger itself and / or by an external axial guide of the forming plunger. In the latter case, in addition to the axial mobility of the forming plunger, the forming plunger is designed to be translatable at an angle to the axial direction of the forming plunger. As mentioned above, the forming plunger and / or its axial guide are in this case translatable together with the forming plunger and have openings through which a vacuum can be applied acting on the flat body of glass, by means of which the glass blank can be held to the forming plunger and / or its guide.

[0037] After the glass blank has been conveyed into the forming space, it floats loosely on the molten metal or, if desired, can be held and fixed by its edge at the edge of the metal bath, i.e. the upper edge of the vessel containing the molten metal or on the guide of the forming plunger, so that the respective position of the glass blank to be formed, in particular the final position intended for forming, can be precisely defined and, if necessary, corrected by movements of a holding device and / or a support device or guide of the forming plunger, which are axially movable independently of the forming plunger. When the molten metal and the forming plunger approach the flat glass blank from the opposite side, the forming of the glass blank takes place.

[0038] Thus, according to one embodiment of the present invention, a glass blank or molten glass can be placed on molten metal disposed in a vessel suitable for receiving the molten metal, such that the glass is substantially suspended on the molten metal. As the forming plunger and the molten metal move closer to each other, the forming plunger can be lowered onto the glass tempered to the forming temperature, whereby the forming plunger forces the soft glass at the forming temperature into the liquid molten metal to form it. During this forming process, the soft glass of the glass blank conforms to the glass contact surface of the forming plunger under the pressure of the forming plunger and takes the shape of the glass contact surface of the forming plunger, while the liquid molten metal acts as a counter plunger for the forming plunger, exerting a uniform counter pressure on the glass blank from the opposite side of the tempered glass blank.

[0039] According to another embodiment of the present invention, the approach between the forming plunger and the molten metal can also be achieved by raising the liquid metal level of the molten metal, so that the forming plunger does not approach the molten metal from above, but during this approach, the molten metal with the floating glass blank approaches the forming plunger and presses the glass blank against the forming plunger.

[0040] According to the invention, the level of the molten metal can be raised by filling the liquid metal receiving compartment with more liquid metal so that the level of the liquid metal rises, or the bottom of the liquid metal receiving compartment and / or the entire vessel in which the metal bath is located can be made movable to raise and lower the level of the liquid metal in the metal bath to bring the molten metal and the forming plunger closer together for the pressing operation and to move them apart for the subsequent demolding operation.

[0041] The above-mentioned embodiments of the invention can also be combined as desired, i.e., by simultaneously raising the level of the molten metal while bringing the forming plunger closer to the surface of the molten metal, such a combination being suitable, for example, for the production of three-dimensional formed flat glass products where high production speeds are desired, since the two approaching movements are simultaneous with each other.

[0042] According to a particularly preferred embodiment of the invention, the flat body of glass to be formed is introduced into the forming space by means of a holding and / or supporting device in such a way that the flat body of glass to be formed rests on the edge of the container containing the liquid metal with its outer edge region.

[0043] In this forming process, the outer edge region of the flat of glass to be formed, which lies at the edge of the vessel, is fixed to the edge of the vessel for the liquid metal, i.e. the edge of the metal bath, by applying pressure to an edge region of the flat of glass to be formed opposite the edge of the vessel, and the edge region of the flat of glass to be formed is fixed to the edge of the vessel. According to the invention, such pressing of the flat of glass to be formed against the edge region can be carried out in a particularly advantageous manner in the circumferential direction by means of a guide of the forming plunger which is movable independently of the forming plunger.

[0044] In this way, the flat body of glass being formed is secured to the edge of the metal bath during the forming process, while at the same time sealing against flooding of the metal bath as the liquid metal level in the metal bath rises during the forming process, particularly as the forming plunger is simultaneously lowered.

[0045] According to this embodiment of the invention, one or more openings can be provided both on the guide of the forming plunger and on the top of the metal bath, for example on its edge, which openings serve both to ventilate and to ventilate the space located between the flat of glass and the surface of the liquid metal after the flat of glass is fixed to the edge of the container. In this way, the level of the liquid metal in the metal bath can be lowered or raised without the formation of undesirable air bubbles or low pressure between the flat of glass and the surface of the liquid metal.

[0046] In this context, it should also be pointed out that in the present invention, the entire flat molded glass is not necessarily tempered to the forming temperature, but rather in an advantageous embodiment, only the three-dimensional forming area is actually tempered. This means that each end area of ​​the flat molded glass can be kept at any time at a handling temperature at which the glass can be gripped and handled. In this way, for example, by the holding and / or supporting device used in the present invention for conveying the flat molded glass into the forming space and removing it from there, it is possible to grip and hold each end area of ​​the flat molded glass even during the actual forming process.

[0047] The tempered glass blank can also be formed by placing the glass blank on a lowered forming plunger during the operation, then tempering the glass blank, then pouring liquid metal into the glass blank to form it, and forming the glass blank, once it has reached the forming temperature, against the lowered forming plunger by the weight of the liquid metal and the additional compressive force applied thereto. This embodiment of the invention also allows for a possibly simultaneous, preferably axial, movement of the forming plunger.

[0048] In the pressing process, the forming plunger comes into contact with the glass surface formed by the forming plunger, causing the glass surface to cool, which in turn causes the flat body to solidify, and the flat body solidifies in the shape produced by the pressing process.

[0049] After the solidification of the produced three-dimensional shaped flat glass product, the flat glass product is cooled until the three-dimensional shaped flat glass product reaches a handling temperature. According to the present invention, the handling temperature is set to a temperature at which the viscosity of each shaped glass is ≧10 7 Such a ≧10 7 At a viscosity of Pas, each formed glass is solidified to such an extent that deformation of the glass sheet does not occur when the glass sheet is handled, so that the glass sheet can be removed from the press.

[0050] It should be noted that, according to the present invention, it is preferred to use aluminum silicate glass to produce the desired three-dimensional shaped flat glass product, but other glasses may also be used. Since these different glasses have, to some extent, significantly different softening and processing temperatures, in the context of the present invention, the processing process is not based on a specific temperature, but on the viscosity required for each process, at which each used glass has a cohesive state, such as liquid, softened or solid, required for each processing step, and each used glass can either be transported or shaped or post-treated, such as fire-polished or other surface adjustments. In FIG. 9, an exemplary correlation between the respective viscosities of different glasses at their respective relevant temperatures is shown for different glasses.

[0051] After the desired three-dimensional shaped flat glass article has cooled to a handling temperature, demolding of the cooled flat article, i.e., the produced three-dimensional shaped flat glass article, is performed.

[0052] According to one embodiment of the present invention, the flat molding of glass or the flat molding of glass forming at least a part of the flat molding of glass is preferably formed by melting the glass at least 10% by weight of the glass before step a), i.e. before the introduction into the molding space between the molten metal and the molding plunger. 6.5 Pas, preferably ≥ 10 7 It is preheated to a temperature having a viscosity of 1 Pas.

[0053] At such a viscosity, the glass blank can still be held and even handled, but since it is already preheated to a temperature close to its forming temperature, tempering of the flat molding or its formed parts to the forming temperature can be carried out very quickly in the press tool.

[0054] In this context, it should also be mentioned that the glass blank may already have softening phenomena in the course of its introduction into the pressing tool, since impurities or microstructures on the blank surface are advantageously smoothed out in the course of the pressing process of the invention, and therefore an important advantage of the inventive method is the fact that blanks with small surface damage or blanks with microstructures can also be used in the inventive process without problems. This applies in particular if the damaged surface is located on the metal bath side of the pressing tool.

[0055] Provided that no preformed glass blanks are used to carry out the method according to the invention, the glass can be poured in liquid form into a molten metal or forming plunger and tempered to its forming temperature by cooling. The method according to the invention is thus not limited to the treatment of preformed glass blanks but can be used in particular in a variety of ways.

[0056] According to the invention, the tempering of the flat molding of glass is carried out, in the case of heating of the blank or the flat molding, by heaters, for example infrared (IR) heaters and / or, optionally supplementarily, at least one induction heater and / or at least one microwave heater. Furthermore, the heating or cooling of the blank can also or additionally be carried out by thermal conduction by heating or cooling the molten metal.

[0057] Further, according to the invention, the molded plunger may have fluid flow paths allowing separate temperature control of the multi-part molded plunger, whereby the molded plunger may be heated and cooled by a fluid to provide an optimal temperature for each process step. A gaseous fluid may preferably be used as the cooling or heating fluid.

[0058] According to one embodiment of the present invention, step c), i.e. bringing the forming plunger and the metal bath closer together, is carried out by at least one linear motor, in particular a servomotor. The use of such a motor to generate a linear movement allows a very precise control of the press tool and, moreover, an immediate and instantaneous reaction in case of a pressure increase.

[0059] As mentioned above, the molten metal used in the present invention is a tin melt, a material that is inert to glass even at high temperatures and allows the production of a qualitatively optimized glass surface while allowing the "repair" of defects on the surface of the glass blank.

[0060] According to the invention, this "repair" property of molten tin is also used for the post-treatment of the finished three-dimensionally formed flat glass product in the form of surface conditioning. For this purpose, the formed flat glass molding can be rotated, for example by a gripper and / or a vacuum holding device, after it has cooled to the handling temperature and contacted with liquid tin on the side that was not in contact with the molten metal during the forming process. Through the contact of the glass with the liquid tin, defects on the glass surface and / or stresses on the glass surface are "corrected" or repaired, respectively, without the need for manual or mechanical post-treatment of the glass surface, for example by grinding or polishing.

[0061] According to a preferred embodiment, the molten metal with which the flat glass moulding comes into contact during the surface preparation is subjected to high frequency vibrations, which can be generated, for example, by ultrasound, in such a way that a planar uniform contact between the flat glass moulding and the liquid metal, i.e. liquid tin, is preferred.

[0062] Furthermore, the process according to the invention is carried out in the absence of oxygen, i.e. in an atmosphere that is preferably inert to the glass, the liquid metal, in particular molten tin, and the material of the forming plunger, for example a noble gas atmosphere, in particular an argon atmosphere, and / or a nitrogen atmosphere and / or a carbon dioxide atmosphere, in this way any oxidation of these components and in particular the tin bath can be avoided.

[0063] According to a preferred embodiment of the invention, the tin bath is layered with the respective inert gas used, where heavy noble gases and carbon dioxide are particularly suitable due to their higher specific gravity compared to air. According to this embodiment, a container of liquid metal, in particular tin, arranged in its area adjacent to the flat mold of glass and / or the guide of the mold plunger, is in fluid communication with a reservoir for the respective glass in which an inert atmosphere is generated above the metal bath.

[0064] According to the invention, for the purpose of inert gas supply, it is also possible to use one or more openings, which allow, for example, ventilation and evacuation of the space between the metal bath and the flat body of glass being formed.

[0065] In order to be able to carry out the actual forming process according to the invention in an inert atmosphere, the glass blank, either held by a gripper, a vacuum holding device or a support device, is brought via an airlock into a space with a controlled atmosphere, which space is filled with the desired inert and / or protective gas or a mixture thereof, respectively, and is preferably under a slight overpressure to prevent the intrusion of environmental air into the space with the controlled atmosphere.

[0066] In the airlock, evacuation is first carried out and then the space is flooded with an inert and / or protective gas. Since this process takes time, according to the invention, a preheating of the glass blank can be carried out at the same time, thus shortening the time sequence of the method according to the invention.

[0067] In this case, instead of evacuating the airlock chamber, it is also conceivable to replace the air with an inert and / or protective gas, so that the inert and / or protective gas which escapes from the forming chamber due to the overpressure in the forming chamber can be used for this purpose.

[0068] According to yet another embodiment of the invention, it is further possible to place the entire pressing device according to the invention under an inert and / or protective gas bell that opens downwards and allows a slight overpressure inside the bell to maintain a controlled atmosphere inside the bell. In this case, the glass blanks and the finished glass products are loaded and unloaded from under the bell. Since the bell opens downwards, an inert gas that is less dense than air is suitable for this embodiment of the invention.

[0069] When the glass blank is supported on a support device, the heating of the glass blank is essentially carried out from above, preferably by infrared radiation, but when the glass blank is held at the edge of the metal bath and / or placed with its edge, the heating of the glass blank is possible not only from above but also from below.

[0070] The use of grippers to hold the glass blank is advantageous according to the invention as the blank can be moved and rotated together with the grippers, which is very advantageous for carrying out, for example, surface conditioning.

[0071] According to the invention, the formed flat glass product can be removed from the pressing tool by a gripper, but also by a vacuum holding device, which can be integrated in the forming plunger and / or in an annular guide of the forming plunger that at least partially surrounds the forming plunger. In this case, according to the invention, the forming plunger is designed to be movable not only axially, but also laterally. Such an embodiment of the invention is particularly advantageous, since the forming plunger comes into contact with the formed flat product during the pressing process in any case and therefore also serves as a protection for the pressed glass surface.

[0072] To remove the flat glass product from the press tool, the forming plunger can have a micro-opening through which a vacuum can be applied, holding the formed flat glass product to the forming plunger. In this way, according to the invention, the finished formed flat glass product can be reliably adhered to the forming plunger during the removal process, and can be separated from the forming plunger in a simple manner by releasing the vacuum after removal.

[0073] As mentioned above, the guide of the forming plunger, which surrounds the forming plunger, can be designed as a ring, for example in the case of a circular forming plunger, and can have an opening through which a vacuum can be applied. This guide, functionally also called a cover ring, for example, is applied to the glass blank along its edge and thus holds the glass blank when low pressure is applied through the openings formed in the guide, the blank or its edge being sucked by the guide. In this way, either the transport of the glass blank or the lifting and picking up of the three-dimensionally formed flat glass product from the molten metal can be performed.

[0074] Furthermore, the glass blank can also be held by a gripper or a support device throughout the entire manufacturing process, whereby the glass blank is first placed on the support device or gripped by the gripper to carry out the process of the invention. With the help of this holding and / or support device, which can be connected, for example, to a transport carriage or other transport device, the glass blank is then transported from the ambient atmosphere into the airlock, where it is heated to a temperature that still allows gripping and transporting the glass blank, while at the same time an exchange of atmosphere takes place in the airlock, in the process of which the ambient atmosphere is replaced by an inert and / or protective gas atmosphere. After completion of the atmosphere exchange, the blank is then transported into the forming space and placed between a volume or container for molten metal and a forming plunger. Heating of the glass blank to the forming temperature then takes place. The glass blank is also held or supported during this process. The glass blank is formed by bringing the molten metal and the forming plunger into close proximity, so that the glass blank is in intimate contact with the molten metal on the one hand and the forming plunger on the other hand, and is shaped such that the molten metal acts as a counter plunger to the forming plunger, forcing the glass blank precisely against the forming contour of the forming plunger.

[0075] When the glass blank is held and fixed on the edge of the metal bath, preferably in a manner that seals the metal bath, additional liquid metal, i.e. liquid tin, is forced into the volume provided for the metal bath during the forming process, so that the liquid level of the metal bath, in particular the tin bath, rises to such an extent that the glass blank comes into contact with the liquid tin, and the glass blank is forced into the desired shape by a forming plunger from the opposite side.

[0076] In the pressing process, the cooling of the formed flat glass product is carried out simultaneously after the completion of the pressing process, respectively, so that the three-dimensional formed flat glass product is solidified into the desired shape. According to the present invention, the cooling is mainly initiated by the forming plunger itself, which has a temperature slightly lower than the forming temperature of the glass toward the end of the pressing process. Since the forming plunger is in direct and immediate contact with the entire formed surface of the flat glass product, a uniform cooling is carried out to the handling temperature of the flat glass product below the forming temperature, and the viscosity of the flat glass product increases, making further forming impossible.

[0077] According to one embodiment of the invention, the forming plunger can have heating and cooling devices for this purpose, so that during the execution of the method according to the invention, the forming plunger can be tempered to the temperature required for the respective process step. Such a heating or cooling device can be designed, for example, in the form of channels or conduits formed inside the forming plunger and through which a heating or cooling fluid can flow. Alternatively, the forming plunger can also be heated, for example, inductively. The same is true for the guide of the forming plunger, since the guide according to the invention has a heating and / or cooling device in order to avoid stresses between the guide and the forming plunger.

[0078] Additionally, it is noted at this point that the metal bath can be heated and cooled depending on the process step so that the glass blank has the optimum temperature and viscosity for forming the glass blank. This means that in addition to using induction and / or infrared heaters to heat the glass blank, the glass blank can be heated by contact with the metal bath or cooled when the metal bath is cooled.

[0079] It should further be noted that the level of the metal bath can be lowered again after the forming process is completed: for this purpose, the metal bath is in fluid communication with a reservoir and / or compensation container for liquid metal, so that the liquid metal required to replenish the metal bath can also be taken from this container.

[0080] After the formed flat glass product has solidified to such an extent that no further undesirable deformation of the flat glass product occurs, the flat glass product is picked up and turned over, so that the sides of the flat glass product that were not in contact with the metal bath during the forming process are also brought into contact with the metal bath, and the surfaces that were previously only in contact with the forming plunger are also brought into contact with liquid tin, which "heals" the impurities and creates a perfectly smooth and defect-free surface of the flat glass product. In this way, the formed flat glass product produced according to the invention has an optimized perfect surface on both sides.

[0081] After surface conditioning has been carried out, the fully formed and surface treated flat glass products are transported by the holding and / or supporting device and its transport device back out of the forming device through the airlock to the outside atmosphere where the atmosphere exchange takes place again.

[0082] According to a further embodiment of the invention, the demolding step can be carried out with the aid of pressurizing the molded flat molding with compressed air. This is particularly useful when the molded flat glass product comes into intimate contact with the mold plunger or its guide, e.g., a ring, during cooling, e.g., due to shrinkage. In this case, compressed air can be used to slowly push the molded flat glass product out of the mold plunger and / or its guide.

[0083] As mentioned above, the demolded flat molding is surface-treated according to the invention on at least one side, in particular by contacting the desired side to be treated with a metal bath or a further metal bath, preferably whilst rotating the flat molding, wherein the further metal bath preferably has a lower temperature than the metal bath used during the moulding process, i.e. in step c).

[0084] At this point, it should be noted that the metal bath used for the post-treatment of one or more surfaces of the three-dimensionally formed flat glass product may be the same metal bath used to form the glass blank. Alternatively, a second metal bath may be provided that is used to perform surface conditioning or treatment. According to the invention, this second metal bath is also a tin bath, so that the second metal bath according to the invention has a somewhat lower temperature than the metal bath used for forming. This is particularly advantageous, since smoothing and repair of the surface of the flat glass product only requires contact with liquid tin, which does not, however, require high tempering, such that melting of the glass occurs. Rather, it is sufficient to perform surface conditioning if only a few μm of the surface of the flat glass product to be treated is softened, so that smoothing of the glass occurs due to the surface tension of the glass.

[0085] Now, the method according to the invention can be carried out both as a continuous, i.e. through-feed process and as a so-called batch process, in which each glass product is held by a holding device or, alternatively, is treated by at least one supporting device and, if appropriate, at least one swiveling device.

[0086] According to a further embodiment of the invention, the glass blank can be placed outside the forming device, i.e. in the ambient atmosphere, on a supporting device such as a lance, by means of which the exchange of the atmosphere to an inert atmosphere is then carried out, being transported into an airlock by a transport device such as a carriage or other displacement mechanism. In this airlock, the glass blank can be preheated to a temperature whose viscosity is still high enough for handling and transporting the glass blank. Subsequently, i.e. after the exchange of the atmosphere, the glass blank leaves the airlock on the supporting device and is guided by the lance of the supporting device, respectively, between the tin bath, i.e. a volume or container for receiving the tin bath, and the plunger, i.e. the forming plunger and its guide, i.e. for example a ring. There, the guide of the forming plunger, which is placed above the glass blank, takes over the further transport of the glass blank, which sucks the edges of the glass blank through a vacuum nozzle, lifts them from the supporting device, e.g. the lance, and deposits them into the tin bath or its edges. The forming plunger, which was initially stored behind the guide, is then moved forward by the guide toward the glass blank, and on the opposite side of the glass blank, the liquid level and / or pressure of the metal bath is raised or increased to such an extent that the metal bath acts as a counter plunger to the forming plunger, forming a glass blank disposed between the forming plunger and the metal bath.

[0087] After the glass blank has been shaped, the produced shaped flat glass product is again gripped by the ring, i.e. sucked in by low pressure, and lifted off the metal bath or the edge of the metal bath.

[0088] The formed flat glass product is then deposited onto a second support device, such as a second lance, and transported out of the former again through an airlock.

[0089] Alternatively, according to the invention, the formed flat glass product can be subjected to surface conditioning before being discharged from the forming device. In this case, the flat glass product lifted from the metal bath by the guide of the forming plunger is gripped by a vacuum gripper on the side opposite the guide and rotated so that the side of the formed flat glass product not yet in contact with the metal bath comes into contact with the tin bath, so that the glass comes into contact with the tin bath and defects are repaired. Also in this case, the tin bath used for forming or a tin bath downstream of this tin bath, optionally having a lower temperature than the tin bath used for forming, can be used.

[0090] It should also be mentioned here that the vacuum gripper, i.e. the vacuum holding device used, can either deposit the formed flat glass products onto a support device after the surface conditioning has been carried out again, or transfer them directly from the forming device via an airlock.

[0091] Furthermore, it should be mentioned that the actual forming process and, if necessary, the surface preparation of the flat glass products can also be carried out at low pressure, mostly in an evacuated chamber.

[0092] Furthermore, the object of the present invention is also solved by an apparatus, in particular for producing glass products, in particular three-dimensional shaped flat glass products, in particular by the method described above, which has a receiving section suitable for receiving molten metal, in particular tin, and a forming plunger opposite the receiving section, in the direction of the receiving section and adjacent to the forming plunger a forming space is arranged in which a flat molding of glass, in particular a glass blank or liquid glass, can be introduced, the forming plunger and the molten metal can be moved close to each other, the forming plunger optionally having openings for applying underpressure or overpressure so that the flat molding of glass can be pressed from the forming plunger on the one hand and from the molten metal on the other hand, which can be formed by pressing on both sides and / or by sucking and fitting the flat molding of glass on the forming plunger.

[0093] According to one embodiment of the present invention, the receiving compartment for the liquid metal, in particular tin, is in fluid communication with a compensation vessel suitable for containing and dispensing molten tin and which can be pressurized if necessary.

[0094] In this way, according to the invention, on the one hand it is possible to increase the tin counterpressure during the forming process, and on the other hand it is possible to use tin from the compensation vessel to increase the liquid metal level, respectively.Furthermore, the compensation vessel can be used to control the liquid metal level when the forming plunger pushes the flat glass shape heated to the forming temperature into the metal bath for forming.

[0095] According to the invention, the shaped plunger is made of or coated with a heat-resistant material, such as, for example, steel, gold, copper, ruthenium, osmium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum or tungsten, or a refractory alloy, such as a carbide or nitride, or a ceramic, which is inert to glass at temperatures in the range of 700°C to 1600°C.

[0096] As mentioned above, the molded plunger may include at least one cavity, in particular at least one passage and / or conduit through which a heating or cooling fluid, in particular a gaseous fluid, may flow.

[0097] In this way, separate tempering of the forming plungers is possible, and their temperature can be adapted to the respective process steps: for example, the forming plungers can be cooled in a controlled manner to facilitate cooling of the finished formed flat glass product, or can be kept hot during the pressing step, if this is desired.

[0098] Additionally, the forming plunger and / or its guide may have an opening that allows an overpressure or overpressure to be created at the interface between the flat molding of glass and the forming plunger.

[0099] In this way, the forming plunger and / or its guide itself can be used as a conveying means for the glass blank on the one hand and for the formed flat glass product on the other hand, by holding and conveying the glass blank or flat glass product with an overpressure on the forming plunger. If the glass blank or flat glass product is not independent of the forming plunger, the application of overpressure can be used. If the application of overpressure is necessary to release the glass blank on the press tool, an inert gas such as nitrogen or argon can be used to generate the overpressure. At this point, compressed air can also be applied. For this purpose, the gas supply of the forming plunger can have a reversing valve so that the desired gas or air can be used to remove the product from the forming plunger.

[0100] According to a further advantageous embodiment of the invention, the device can comprise at least one transport carriage for introducing flat mouldings of glass into the moulding space and / or removing the moulded flat glass products from it, via an airlock of the device, which serves to generate an exchange of the outside air atmosphere for an inert gas and / or protective gas atmosphere or a low pressure or vacuum, respectively, in the actual moulding space and / or in the after-treatment space. Here, the transport carriage can be moved between a position inside the press tool in the pressing position and a position outside the press tool, whereby both the glass blank and the finished moulded flat glass product can be transported with the help of the transport carriage. In this way, either a moulding plunger and / or its guide, or alternatively other support devices such as holding devices or lances, can be attached to the transport carriage, in order to transport both the glass blank into the press tool and the finished moulded flat glass product thereafter outside the press tool. Furthermore, the transport carriage can also have several moulding plungers, holding devices and / or support devices, each of which forms and transports the glass blank and the finished moulded flat glass product alternately or successively. In this way, according to the invention, for example, a circulating operation, preferably continuous, is possible.

[0101] As mentioned above, the device according to the invention can be operated either in batch mode or in continuous mode as desired. When operating in batch mode, the device according to the invention has only one airlock, but for operating in continuous mode, the device according to the invention can also have two or more airlocks, preferably arranged opposite each other, where a first airlock serves as an input airlock and a second, particularly opposite, airlock serves as an output airlock.

[0102] Furthermore, the device according to the invention comprises at least one heater, for example an infrared (IR) heater and / or optionally additionally at least one induction heater and / or at least one microwave heater, for heating in particular the glass blank and, if desired, the components of the press tool, in particular the metal bath.

[0103] According to a further advantageous embodiment of the invention, the molded plunger can be exchangeable, preferably by means of at least one coupling device. Possible further couplings can be provided for components connected to the molded plunger, such as a fluid supply or a vacuum device.

[0104] A further important aspect of the present invention is that the forming plunger can be designed as one piece, but also as a multi-piece. The multi-piece design of the forming plunger makes it possible to produce flat glass products with, for example, undercuts, where the forming plunger or the respective parts of the forming plunger covering the respective undercuts can retract to the extent possible the release of the formed flat glass product. According to the present invention, the respective parts of the forming plunger designed as a multi-piece can be moved separately, independently of each other, and the individual parts of such a multi-piece forming plunger can be tightly joined to each other during or before the pressing or forming process, so that the multi-piece forming plunger has a smooth and uniform surface during the forming process for forming the flat glass product.

[0105] Furthermore, the object of the present invention is also solved by using a molten metal, in particular a tin melt, which acts as a counter plunger to the solid forming plunger and is used for the production of three-dimensional formed flat glass products.

[0106] In summary, the method according to the invention and its advantages, i.e. the use of liquid tin as a liquid glass contact material, can be described as follows.

[0107] The use of liquid tin makes it possible to carry out the forming process not only at the cooling stage, but already at the previous stage, i.e., at the stage of adjusting the glass to the optimum forming temperature and temperature uniformity, so that the glass can be fed to the forming process under optimum conditions.

[0108] Additionally, the method according to the invention allows for the expansion of temperature parameters in the process since the tin temperature not only minimizes the temperature delta between the mold and the glass, but can also reverse the temperature delta.

[0109] Thus, when the glass blank is loaded, the tin bath can have a higher temperature than the glass itself has when it is loaded, and in this case the tin bath can transfer its temperature to the glass.

[0110] Furthermore, due to the high thermal conductivity of tin, the tin bath allows for very rapid temperature control during the heating process as well as preconditioning of the glass blank in the form of heating to the forming temperature and holding the temperature during the forming process, allowing control of the temperature parameters during forming and advantageously increasing the forming window.

[0111] This leads to improved process control through active control of both time and forming pressure, holding pressure and temperature control at the individual process steps, which allows homogenization of the glass over time, i.e., control of heating, reheating and temperature gradients of the glass during forming and cooling.

[0112] Thus, increased flexibility in temperature control is achieved through active temperature control rather than through passive thermal conductivity or indirect air / water cooling of the mold tooling as in the prior art.

[0113] The regulation of the tin pressure can be achieved by at least one servo valve.

[0114] Process control can be minimized in terms of reducing process times in the actual forming and shaping process, for example including downstream processes such as upstream heating of the glass blank and dedicated cooling if necessary.

[0115] Additionally, the use of a tin bath in the forming process of the present invention can improve the surface quality of the formed three-dimensional flat glass by contact with tin.

[0116] In this manner, the surface structure of the molded three-dimensional flat glass can be optimized by forming a thin tin oxide layer on the molded glass surface as an inherent component of the glass.

[0117] Furthermore, in an intermediate process step, the sides of the glass parts that were not in contact with the tin bath due to the three-dimensional nature of the glass product are contacted with warm liquid tin in a temperature range where no geometric deformation occurs, effectively "repairing" any surface defects in the glass.

[0118] Further embodiments of the invention will become apparent from the dependent claims.

[0119] The invention will now be described with reference to examples and in more detail with reference to the figures, which are given below. [Brief description of the drawings]

[0120] [Figure 1] FIG. 1 is a schematic view of an apparatus according to the invention for producing a three-dimensionally shaped flat glass product according to a first embodiment in an open position. [Diagram 2] FIG. 2 is a schematic view of the device according to the invention according to the embodiment shown in FIG. 1, on which a flat glass blank is laid. [Diagram 3] FIG. 2 is a schematic diagram of an apparatus according to the invention according to the embodiment shown in FIG. 1 for preparation of a molding process. [Figure 4] FIG. 2 is a schematic view of the apparatus according to the invention according to the embodiment shown in FIG. 1 in a further preparation state for the moulding process. [Diagram 5] 2 is a schematic diagram of the device of the present invention during a molding process according to the embodiment shown in FIG. 1; [Figure 6] FIG. 3 is a schematic enlarged detail view of the section Z marked in FIG. 2. [Figure 7] FIG. 4 is a schematic enlarged detail view of section Y marked in FIG. 3. [Figure 8] FIG. 5 is a schematic enlarged detail view of section X marked in FIG. 4. [Figure 9] FIG. 2 is an exemplary diagram showing the correlation between the respective viscosities of different glasses and their associated temperatures.

[0121] In the following description, the same reference numbers are used for identical and similarly acting parts.

[0122] Fig. 1 is a schematic view of an apparatus 1 for producing flat glass sheets 10 according to a first embodiment of the invention. According to Fig. 1, the apparatus 1 of the invention is shown in an open, starting position.

[0123] The device 1 according to the invention essentially comprises three subunits: a plunger unit 1a, a transport unit 1b for a flat molding 10 of glass, and a counter-plunger unit 1c designed as a metal bath unit.

[0124] The plunger unit 1a in turn comprises a shaped plunger 20 and a plunger receiver 80 to which the shaped plunger 20 is attached by a fastening device, preferably a quick clamping system 90. The plunger unit 1a further comprises a covering unit comprising a fastening ring 100, a suspension bolt 110 fastened to the fastening ring 100 and directed perpendicularly downward, i.e., toward the counter plunger unit 1c, in which the bolt 110' is axially guided, a receiver 120 and a covering ring 60. The receiver 120 serves to fasten the bolt 110' slidably arranged on the suspension bolt 110, and the cooperation of the fastening ring 100, the suspension bolt 110, the bolt 110', the receiver 120 and the covering ring 60 allows the plunger unit 1a, in particular the shaped plunger 20, to be guided.

[0125] The transport unit 1b consists essentially of a holding device 70, which makes it possible to hold, in particular support and transport, the flat mouldings 10 of glass.

[0126] According to the embodiment of the invention shown in Fig. 1, the opposed plunger unit, i.e. metal bath unit 1c, comprises two heaters 40, which comprise at least one heating element 41 and a coil 42 for inductively heating the metal bath. Furthermore, the opposed plunger unit 1c comprises a tubular container 50 for receiving the liquid metal, in particular tin 30, inlet and outlet openings 125 for the liquid metal, an inert gas inlet 130 and an inert gas outlet 135, via which an inert gas, e.g. carbon dioxide, can be supplied and exhausted to cover the metal bath 30.

[0127] Furthermore, the counter plunger unit 1c comprises an inert gas compartment 138, which is arranged above the liquid level 35 of the metal bath 30 and serves to cover the metal bath 30 with an inert gas, which is particularly heavier than air. The inert gas compartment 138 is in turn in fluid communication, in particular in gas communication, with an inert gas receiving compartment 139 via an annular gap 137, which is shown in detail in Fig. 7. The inert gas receiving compartment 139 and, if desired, the annular gap 137 itself are in fluid communication, in particular in gas communication, with the inert gas inlet 130 and the inert gas outlet 135.

[0128] Furthermore, the counter plunger unit 1c is provided with a quick-change system 150 for connection to a press or lifting device (not shown), by means of which the entire counter plunger unit 1c and / or the container 50 can be vertically raised and lowered, inter alia, relative to the outer sleeve 140 and the sealing disk 145. Such relative movement is evident, for example, from a comparison of Fig. 1 with Figs. 3-5, where Figs. 1-5 are diagrams showing respective operating states of the apparatus of the present invention, which are reversibly passed through the apparatus of the present invention to produce a three-dimensionally shaped flat glass 10.

[0129] According to the invention, the counter plunger unit 1 c further comprises an outer sleeve 140 surrounding the metal bath 30 and having a sealing disk 145 .

[0130] According to FIG. 1, the plunger unit 1a, the conveying unit 1b and the counter plunger unit 1c are shown diagrammatically separated from each other.

[0131] FIG. 2 shows a further flow of the forming process for producing a three-dimensional shaped flat glass sheet 10 according to the present invention, in which the flat glass sheet 10 is deposited by a holding device 70 onto an end 55 of a tab for liquid metal 50 .

[0132] 3 shows that in a further step of the forming process according to the invention for producing a three-dimensionally shaped flat glass product 10, the container 50 for the liquid metal 30 is raised relative to the outer sleeve 140 and the sealing disk 145, and by the raising of the container 50 for the liquid metal, the inert gas is conveyed, especially under pressure, from the inert gas compartment 138 through the annular gap 137 to the inert gas receiving compartment 139. In this state, the flat glass blank 10 rests on the one hand on the end of the tab end 55 of the container 50 for the liquid metal 30 and on the other hand is in contact with the liquid metal 30 on its underside. The contact of the edge of the flat glass blank 10 with the tank edge 55 ensures that the edge of the flat glass blank 10 remains cooled with respect to the part of the flat glass blank 10 in contact with the liquid metal 30, and after lowering the cover ring 60 on the edge of the flat glass blank 10, a metal-free seal is provided between the tank edge 55 and the flat glass blank 10 in the course of the subsequent pressing process shown in FIG.

[0133] The operating state of the device according to the invention shown in Fig. 5 shows how the flat glass blank 10 is formed into a three-dimensionally formed flat glass 10 by lowering the forming plunger 20. The liquid metal 30 is displaced during the forming process according to the desired shape of the three-dimensionally formed flat glass 10, so that the tray 50 for the liquid metal 30, which is a tank provided for this purpose, and the inlet and outlet openings 125 for the liquid metal 30 are in fluid communication with a pressurizable compensation container (not shown) which can control the liquid level of the metal bath on the one hand and generate a counter pressure against the forming plunger 20 on the other hand, and the metal bath 30 acts on the side of the flat glass 10 formed opposite the forming plunger 20. Furthermore, Figs. 6, 7 and 8 show detailed views of the parts Z, Y and X marked in Figs. 2 to 4, respectively.

[0134] In the subsequent process of producing the desired three-dimensionally shaped flat glass 10, after the shaping of the flat glass 10, the process control is reversed from that of the shaping of the apparatus of the present invention, and the plunger unit 1a is removed from the counter plunger unit 1c, followed by the transfer unit 1b with the flat glass 10 being removed from the shaping position. The shaped flat glass 10 can then be removed from the holding device 70, for example by a vacuum holder, and placed upside down on another metal bath 30 for surface conditioning. It is also conceivable that at this point, the end of the flat glass 10 is first removed, and the flat glass 10 after the inversion is surface-conditioned in the same metal bath 30 that also served as the counter plunger to the shaping plunger 20.

[0135] It should be noted at this point that all the above parts, considered separately or in any combination, and in particular the details shown in the drawings, are claimed as essential to the invention, the variations of which are well known to those skilled in the art. [Explanation of symbols]

[0136] 1. Apparatus of the Present Invention 1a Plunger unit 1b Transport unit 1c Opposed plunger unit, metal bath unit 10 Flat glass moldings 20 Molded plunger 30 Melting of liquid metal, metal bath 35 Metal bath liquid level 40 Heater 41 Heating element 42 Coil 50 Receivers, containers, liquid metal bathtubs 55 Bathtub edge 60 Frames, Rings, Coverings 70 Holding device 80 Plunger receiver 90 Quick Clamp System 100 Fastening Ring 110 Suspension bolt 110' Bolt 120 Receiver 125 Liquid metal inlet and outlet openings 130 Inert gas inlet 135 Inert gas outlet 137 Annular Gap 138 Inert Gas Compartment 139 Inert Gas Receiving Section 140 Outer sleeve 145 Sealing disk 150 Quick Change System

Claims

1. A method for forming a glass product, comprising: a) placing a flat glass preform between a forming plunger and molten metal; b) annealing at least one portion formed from the flat glass preform to a forming temperature of the glass having a viscosity in the range of 10 Pa·s to 10 ６．５ Pa·s; c) moving the forming plunger and the surface of the molten metal closer to each other by at least one linear motion so that the flat glass preform is pressurized on one side by the forming plunger and on the other side by the molten metal, and the flat glass preform is formed by pressurization on both sides and / or suction onto the forming plunger to fit; d) cooling the formed flat glass preform to a handling temperature below the forming temperature at which the glass has a viscosity of ≧10 ７ Pa·s; e) demolding the cooled flat glass preform. A method.

2. Before step a), preheating the flat glass preform to a temperature at which it has a viscosity of ≧10 ６．５ Pa·s. The method according to claim 1.

3. Pouring the flat glass preform liquid onto the molten metal or the forming plunger, and then cooling to the forming temperature. The method according to claim 1.

4. The annealing of the flat glass preform is performed by at least one heater and / or at least one microwave heater, and / or by heating or cooling the molten metal. The method according to any one of claims 1 to 3.

5. It is carried out in a state where oxygen is absent, and / or in an atmosphere inert to the materials of the glass, liquid metal, and forming plunger, and / or in a carbon dioxide atmosphere. The method according to any one of claims 1 to 3.

6. The releasing step is performed by pressurizing the formed glass flat formed article with compressed air. The method according to any one of claims 1 to 3.

7. The released glass flat formed article is surface-treated on at least one surface, and is surface-treated by contacting a metal bath or a second metal bath while turning over the glass flat formed article, and the second metal bath has a lower temperature than the metal bath used during step c). The method according to any one of claims 1 to 3.

8. An apparatus for manufacturing a three-dimensional formed flat glass product by the method according to any one of claims 1 to 3, having a receiving section suitable for receiving the molten metal and a forming plunger on the opposite side of the receiving section; A forming space is formed between the receiving section and the forming plunger, and the glass flat formed article can be introduced therein. The forming plunger and the molten metal can move closer to each other. The forming plunger has an opening for applying a low pressure or overpressure, if appropriate. The glass flat formed article is pressurized on one side by the forming plunger and on the other side by the molten metal, and is formed by pressurizing on both sides and / or sucking and conforming the glass flat formed article onto the forming plunger. Apparatus.

9. The receiving section is in fluid communication with a container suitable for containing molten tin and optionally pressurizable. The apparatus according to claim 8.

10. The forming plunger is made of a heat-resistant material that is inert to the glass at a temperature in the range of 700°C to 1600°C, which is a heat-resistant metal such as steel, gold, copper, ruthenium, osmium, zirconium, hafnium, niobium, tantalum, chromium, molybdenum, or tungsten, or a refractory alloy or ceramic that is a carbide or nitride, or is coated with such a heat-resistant material. The apparatus according to claim 8.

11. The forming plunger has at least one cavity through which a heating or cooling fluid for gas flows. The apparatus according to claim 8.

12. The forming plunger includes at least two plunger components, and each plunger component is independently movable. The apparatus according to claim 8.

13. The forming plunger is surrounded by a frame, and the frame surrounding the forming plunger optionally has an opening. Thereby, it is possible to generate a low pressure or overpressure through the opening on the contact surface between the glass flat formed article and the forming plunger. The apparatus according to claim 8.

14. It includes at least one conveying device. At least one of the conveying devices is for guiding a holding device and / or a supporting device, and in the form of a gripper or a lance, for introducing the glass flat formed article into the forming space and / or for taking out the formed flat glass product from the forming space. The apparatus according to claim 8.

15. Use of molten metal as a counter plunger of a fixed die forming plunger for the production of a three-dimensional formed flat glass product by the method according to any one of claims 1 to 3.

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