Forming device and method for forming a glass blank

Abstract

The invention relates to a forming device (1) for forming a glass blank (36), comprising a first station and a second station for controlling the temperature of and / or forming the glass blank (36), wherein the first station has a first temperature control unit (18) and / or the second station has a second temperature control unit (38-42), which are arranged and designed to control the temperature of a transfer unit (28) holding the glass blank (36) at a predefined temperature within a temperature control time period, a control device (134) coupled for signal communication with the first temperature control unit (18) and / or the second temperature control unit (38-42), which is designed to adjust the first temperature control unit (18) and / or the second temperature control unit (38-42) with a temperature control process parameter, wherein the control device (134) is designed to alter the temperature control process parameter within the temperature control time period in such a way that the transfer unit (28) can be temperature-controlled with a predefined temperature profile.

Description

[0001] Forming device and method for forming a glass blank

[0002] The invention relates to a forming device and a method for forming a glass blank, in particular a volume blank and / or a thin glass.

[0003] Forming devices and methods for forming glass blanks are generally known. Forming devices are typically designed to first heat the glass blank to a forming temperature in one or more stages and then form the glass blank. The formed glass blank can be cooled in a subsequent station.

[0004] Tempering and forming can be carried out either isothermally or non-isothermally. In isothermal forming, the mold performing the forming has essentially the same temperature as the glass blank. In isothermal forming, the glass blank is usually already provided in the mold, which is successively moved through the various stages of the forming device so that the mold and glass blank are heated together, resulting in essentially the same temperature in both units. In non-isothermal forming, the temperature of the mold differs from the temperature of the glass blank. For example, the glass blank can be heated independently of the mold and then transferred to the mold for forming.

[0005] The disadvantage of isothermal forming of glass blanks is that it involves a long cycle time, since the tempering of the glass blanks must be carried out at a low temperature gradient at each station. If this temperature gradient were too high, especially during cooling of the glass blank, it would result in quality defects in the manufactured glass product. Furthermore, excessively high temperature gradients can lead to thermal shock in the mold.

[0006] Especially in the manufacture of high-precision glass products, the quality defects described above are unacceptable, so the resulting glass products either require reprocessing or are rejected. Since such glass products are often used in mass-produced products, such as smartphones or the automotive sector, reprocessing is not an economically viable option.

[0007] Industry demands that glass blanks be formed with such high quality that post-processing is unnecessary. Furthermore, industry demands that glass blanks be formed with a high degree of process reliability, so that subsequent quality controls after forming can be reduced or eliminated.

[0008] US 2017 / 0349472 A1 discloses a device for molding curved glass. KR 101845746 B1 discloses a molding system for lenses. KR 102019 0 109075 A discloses a molding device for curved plates. CN 107365063 A discloses a hot-pressing device for three-dimensional protective glasses for mobile terminals. JP 2002154836 A discloses a bending device for bending glass plates to produce curved mirrors.

[0009] It is therefore an object of the invention to provide a forming device and a method for forming a glass blank that reduce or eliminate one or more of the aforementioned disadvantages. In particular, it is an object of the invention to provide a solution that enables rapid heating of glass blanks, particularly in an isothermal process.

[0010] This object is achieved with a forming device and a method according to the features of the independent patent claims. Further advantageous embodiments of these aspects are specified in the respective dependent patent claims. The features disclosed in the patent claims, the description, and the drawings can be combined individually in any technologically expedient manner, with further embodiments of the invention being shown.

[0011] According to a first aspect, the object mentioned at the outset is achieved by a forming device for forming, preferably for isothermal forming, a glass blank, in particular a volume blank and / or a thin glass, comprising a first station and a second station for tempering and / or forming the glass blank, wherein the first station has a first tempering unit and / or the second station has a second tempering unit, which are arranged and designed to temper a transfer unit holding the glass blank to a predefined temperature within a tempering period, a control device which is signal-coupled to the first tempering unit and / or the second tempering unit and which is designed to set the first tempering unit and / or the second tempering unit with a tempering process parameter, wherein the control device is designedto change the tempering process parameters within the tempering time period in such a way that the transfer unit can be tempered with a predefined temperature profile.

[0012] The invention is based on the finding that quality defects in formed glass blanks arise when the transfer units are heated too strongly at the beginning of the heating process at a single station and / or cooled too strongly during the cooling process. In particular, sudden thermal loading can lead to residual stresses and unfavorable thermal expansion, and consequently to cracks, deformations, and wear on the glass and mold or tool. This can cause, among other things, thermal shocks and a decrease in glass quality. Furthermore, unfavorable tempering can negatively influence stress birefringence. In general, it has been found that unfavorable tempering causes defects of varying magnitudes in shape deviation, for example, deviations in roughness, waviness, and profile.

[0013] This leads to poor glass quality and an unstable forming process. This effect was previously compensated for by very low heating power, which, however, resulted in a long warm-up time and thus a long cycle time.

[0014] The individual tempering stations typically always have the same temperature, for example, 400°C. As soon as a transfer unit with a glass blank is placed on this station, the transfer unit is heated with a high temperature gradient, since the temperature difference between the station and the transfer unit is large. The invention is based on the finding that, at the beginning of the tempering period, the transfer unit or the glass blank is initially exposed to a low heating power, for example, and the heating power is subsequently increased. This leads to better glass quality and a stable forming process.

[0015] The forming device is designed for forming a glass blank. Forming can be understood, for example, as a change in geometry and / or bending. The forming device can be designed for forming solid glass and / or thin glass. In particular, the forming device can be designed for pressing, in particular for forming solid glass, press-bending, molding, countersinking, and / or deep drawing, in particular for forming thin glass. The forming device is preferably designed for isothermal forming of the glass blank, so that the glass blank and the mold have essentially the same temperature.

[0016] The glass blank, for example, is a preform blank that already meets high requirements for weight tolerance and surface quality. The glass blank can, for example, be a volume blank. A volume blank can, for example, have a spherical, cylindrical, lenticular, or conical geometry. Furthermore, the glass blank can be a thin glass, which is characterized by a thickness orthogonal to a planar extension that is several times smaller than the planar extension. Formed thin glass is used, for example, as screen covers for smartphones.

[0017] The forming device comprises the first station and the second station for tempering and / or forming the glass blank. For example, the forming device can have a first station for tempering and a second station for forming the glass blank. The station for tempering the glass blank can, for example, be arranged upstream of the station for forming the glass blank in the process direction. Alternatively, the station for tempering the glass blank can be arranged downstream of the forming station, for example for cooling.

[0018] A station is understood to be a section of the forming device in which the transfer unit with the glass blank remains for a predetermined time during the process. In particular, the transfer unit with the glass blank remains at a single station during the tempering period. A station can have one, two, or more units for carrying out the forming, for example, pressing and / or tempering. For this purpose, in addition to the tempering units described below, press dies, further

[0019] Tempering elements, for example for convective heating, oxygen traps to prevent unwanted oxidation, sensors and the like can be arranged.

[0020] The first station has a first temperature control unit and / or the second station has a second temperature control unit. A temperature control unit is generally described below, whereby this description applies to the first temperature control unit and / or the second temperature control unit. The temperature control unit is arranged and designed to temperature control the transfer unit holding the glass blank to the predefined temperature within the temperature control period. A temperature control unit is generally understood to be a unit with which the transfer unit and / or the glass blank can be temperature controlled, in particular heated or cooled. The temperature control unit is arranged and designed to temperature control the transfer unit by means of heat conduction through mechanical contact.The temperature control unit can be designed in two parts with an upper temperature control unit and a lower temperature control unit, wherein the transfer unit can be arranged between the upper temperature control unit and the lower temperature control unit.

[0021] The tempering time depends on the process and, for example, on the molds used, the glass blanks, and / or the number of stations. A thin glass blank often requires a shorter tempering time than a bulk blank. The tempering time is preferably between 0.5 minutes and 10 minutes, especially between one and four minutes.

[0022] It is preferred that the temperature control unit is arranged and configured such that the transfer unit can be arranged thereon. For example, the temperature control unit can have a temperature control surface on which the transfer unit can be arranged. It is particularly preferred that the temperature control surface is oriented substantially horizontally during intended operation, so that the transfer unit can be arranged thereon. The temperature control surface can also have positioning elements for positioning the transfer unit on the temperature control surface in a predetermined position.

[0023] The transfer unit is arranged and designed to hold the glass blank. Holding the glass blank can be understood as any positioning of the glass blank. This can be done, for example, by means of a force-fitting and / or form-fitting connection. In particular, it is preferred that the glass blank can be arranged in a lower mold of the transfer unit. The transfer unit is preferably a mold with an upper and / or lower mold. Furthermore, it is preferred that the transfer unit has a cavity, in particular a first, lower cavity and / or a second, upper cavity. The glass blank can be arranged, in particular, within the cavity. The first cavity can be formed by a first mold unit of a mold and / or the second cavity by a second mold unit of a or the mold. The first and / or the second mold unit can be guided by means of an outer sleeve.

[0024] The transfer unit is further arranged and designed to be moved from the first station to the second station by means of a feed unit. For this purpose, the transfer unit can, for example, have coupling elements. The forming device further comprises a control device which is signal-coupled to the first temperature control unit and / or the second temperature control unit and which is designed to set the first temperature control unit and / or the second temperature control unit with a temperature control process parameter. In particular, it is preferred that the control device is designed to each set the first temperature control unit and the second temperature control unit with a temperature control process parameter. For this purpose, the control device can, for example, set the first temperature control unit with a first temperature control process parameter and the second temperature control unit with a second temperature control process parameter.Adjustment can also be understood as controlling and / or regulating. In particular, the temperature control process parameter can be continuously adjusted and thus changed. The control device can also be a computing unit.

[0025] The term "temperature control process parameter" refers, in particular, to any adjustable parameter that influences the temperature control of the transfer unit. The temperature control process parameter can directly or indirectly affect the temperature and / or heating power of the temperature control unit.

[0026] The control device is further configured to change the tempering process parameter within the tempering period such that the transfer unit can be tempered with the predefined temperature profile. With a control device configured in this way and tempering units adjusted in this way, it is possible for the transfer unit to be arranged on the tempering unit shortly before or at the beginning of the tempering period and, for example, for the temperature difference between the tempering unit and the transfer unit to be so small that thermal shock is prevented. Since every tempering process generally has a delay, with knowledge of the delay, which depends, for example, on the material and size of the mold and the glass blank, the tempering process, for example an adjustment of the heating output, can be initiated not only before contact between the transfer unit and the tempering unit, but also beforehand.

[0027] Furthermore, the temperature control unit can be adjusted so that, despite the existing temperature difference, the transfer unit does not overheat. As explained in more detail below, for example, the P parameter can be set so low at the beginning of the temperature control period that excessive heating does not occur. As the temperature control period progresses, the heating power can then be increased so that, taking material and / or process parameters into account, the transfer unit and the glass blank can be heated to their maximum intensity and thus quickly, thus reducing the cycle time of the forming device.

[0028] A preferred embodiment of the forming device is characterized in that the control device is designed to

[0029] Tempering process parameters are to be set in such a way that at an initial time of the tempering period a first initial temperature of the first

[0030] temperature control unit and / or a second initial temperature of the second

[0031] Tempering unit is adjustable, and at an end time of the

[0032] A first target temperature of the first tempering unit and / or a second target temperature of the second tempering unit can be set during the tempering period, wherein for heating the glass blank, the first initial temperature is lower than the first target temperature and / or the second initial temperature is lower than the second target temperature. Furthermore, it is preferred that for cooling the glass blank, the first initial temperature is higher than the first target temperature and / or the second initial temperature is higher than the second target temperature.

[0033] The start time of the tempering period is preferably the beginning of the tempering period. Furthermore, it may be preferred that the start time lies within the first 10% of the tempering period. It is further preferred that the end time represents the end of the tempering period. Furthermore, it may be preferred that the end time lies within the last 10% of the tempering period. It may be preferred that the first target temperature corresponds to the second start temperature. Furthermore, it may be preferred that a ratio of the second start temperature to the first target temperature is less than 1.5, preferably less than 1.25, further preferably less than 1.1.

[0034] Furthermore, it is preferred that a predefined temperature profile is provided between the first initial temperature and the first target temperature and / or between the second initial temperature and the second target temperature by the second temperature control unit.

[0035] In a further preferred embodiment of the forming device, it is provided that the control device has or is a controller unit and the tempering process parameter is or comprises a P parameter of the controller unit, in a first time period of the tempering period the controller unit has a first P value and in a second time period of the tempering period following the first time period the controller unit has a second P value, and the second P value is higher than the first P value.

[0036] The P parameter of the controller unit is generally known as the proportional component and is also referred to as the controller gain. The higher the P value selected for the controller unit, the more strongly the controller reacts to a deviation of the actual temperature from the setpoint temperature. If the transfer unit with a low temperature is arranged next to the temperature control unit, the controller unit with a high P value would provide a high heating output in order to regulate from the low actual temperature to the setpoint temperature as quickly as possible. This high P value would result in the transfer unit being heated with a high temperature gradient at the beginning of the temperature control period. This has the disadvantages already mentioned. With a controller unit that has a variable P value in the form of the P parameter, it can be ensured that, for example, the aforementioned thermal shock does not occur.

[0037] Additionally or alternatively, the controller unit can have an I parameter and / or a D parameter, which can also be configured variable. Such controller units are also referred to as P, PI, PD, or PID controllers.

[0038] In a further preferred embodiment of the forming device, the tempering process parameter relates to a temperature and / or a pressure. This temperature and / or pressure can be that of a tempering unit, the glass blank, and / or a tempering element acting on the glass blank.

[0039] A further preferred embodiment of the forming device is characterized in that the tempering process parameter relates to a temperature of the transfer unit and / or a tempering element acting on the glass blank, wherein the predefined temperature depends on a point in time within the tempering period. With such a tempering process parameter, a temperature profile can advantageously be adjusted.

[0040] It is further preferred that the tempering process parameter relates to a tempering pressure with which the tempering element acts on the glass blank, wherein the tempering pressure depends on a point in time within the tempering period. The greater the pressure of the tempering element, the greater the heat transfer to the glass blank. However, the tempering pressure should not exceed a predetermined pressure, as the glass blank could be damaged or destroyed. It is further preferred that the tempering pressure be provided in an oscillating manner. It is preferred that the temperature is increased, in particular for heating, and decreased for cooling. Furthermore, it is preferred that the tempering pressure is adjusted, in particular increased.

[0041] A further preferred development of the forming device is characterized in that the control device is configured to adjust the tempering process parameter such that, in a first time period of the tempering period, the temperature rises or falls with a first temperature gradient, and in a second time period of the tempering period following the first time period, the temperature rises or falls with a second temperature gradient, wherein the second temperature gradient is greater than the first temperature gradient. This has the advantage that the transfer unit or the glass blank is initially heated with a low temperature gradient and subsequently with a higher one, thus reducing or eliminating the aforementioned disadvantages.

[0042] Furthermore, it is preferred that the control device is configured to adjust the tempering process parameter such that, in a first time period of the tempering period, the tempering pressure has a first pressure value, and, in a second time period following the first time period, the tempering pressure has a second pressure value, wherein the second pressure value is greater than the first pressure value. Due to the increasing temperature of the glass blank, a higher tempering pressure can be applied in the second time period, thus enabling better tempering.

[0043] A further preferred embodiment of the forming device is characterized in that the first temperature control unit and / or the second temperature control unit has heating elements that can be separately controlled by the control device, and the control device is configured to control the heating elements such that the first temperature control unit and / or the second temperature control unit has or have a predefined temperature distribution. Separately controllable heating elements are understood to mean, in particular, that they can be controlled individually.

[0044] For example, it may be preferable to provide a lower heating power in a central section of a temperature control unit than in an outer section surrounding the central section. The outer section typically loses more heat than the central section, so such a control enables a more homogeneous temperature distribution and thus better heating of the transfer unit.

[0045] A further preferred embodiment of the forming device is characterized in that the first tempering unit and / or the second tempering unit has or have a cooling unit which is or are arranged and designed to cool the first tempering unit and / or the second tempering unit.

[0046] Using a cooling unit, the temperature control unit can be cooled to a predetermined temperature, for example, at the end of the temperature control period or before the temperature control period. This may be necessary, for example, to achieve the temperature profile described above or to enable a short cycle time.

[0047] In a further preferred embodiment, it is provided that the control device is configured to heat a core of the first temperature control unit and / or the second temperature control unit more strongly than an outer section surrounding the core in a first time segment of the temperature control period, so that the heat is transported from the core into the outer section in order to avoid a thermal shock.

[0048] Furthermore, it may be preferred that the control device is configured to cool the core with the cooling unit in a second time period of the tempering period following the first time period, so that heat is transported from the outer portion to the transfer unit and cooling of the first tempering unit and / or the second tempering unit is ensured after the tempering period has elapsed.

[0049] In a further preferred embodiment, it is provided that the control device is configured to cool a core of the first temperature control unit and / or the second temperature control unit more strongly than an outer section surrounding the core in a first time segment of the temperature control period.

[0050] The cycle time is influenced, among other things, by how quickly the temperature control unit can be cooled again after the temperature control period in order to accommodate another transfer unit with a low initial temperature. In this design variant, the core of the temperature control unit is cooled again before the end of the temperature control period. Due to the mass of the temperature control unit, cooling the core does not immediately lead to a cooling of the temperature control surface and thus to a cooling of the transfer unit. However, this prior cooling of the core leads to a subsequent faster cooling of the entire temperature control unit, thus reducing the cooling time between two consecutive temperature control periods.

[0051] In a further preferred embodiment, it is provided that the first temperature control unit and / or the second temperature control unit has a heating unit, preferably with an inductive heating element. It is preferred that the heating unit and the cooling unit are formed integrally, wherein the transfer unit can be arranged on the cooling unit, so that heat provided by the heating unit is transferred through the cooling unit to the transfer unit. Furthermore, the heating unit can have the heating element described above, wherein the cooling unit can be present. For example, cooling can also take place by means of convection, for example by supplying a gaseous cooling medium or a thermal oil.

[0052] In a preferred embodiment of the forming device, it is provided that the heating unit has an upper side for arranging the transfer unit and that one or the heating element is arranged on an underside of the heating unit facing away from the upper side.

[0053] In a preferred embodiment of the forming device, it is provided that a heat-conducting intermediate layer is arranged between the cooling unit and the heating unit in order to conduct heat to the transfer unit during normal operation.

[0054] A further preferred development of the forming device is characterized in that the heating unit has two or more heating elements that are at least partially enclosed by a heating ring. For example, the heating unit can have two or more heating elements arranged parallel to one another, for example heating cartridges. The heating ring can, for example, also be designed in the shape of a heating cartridge or as a heating channel with a heating fluid. The heating ring encloses the other heating elements at least partially or essentially completely. This arrangement prevents an outer section from having a lower temperature than a central section of the heating unit or the temperature control unit, since the outer section generally requires a higher heating output than the core or the central section, since the outer section has a higher heat loss.

[0055] Furthermore, it is preferred that the heating unit has two or more heating rings, arranged, for example, as heating coils. In this embodiment, the heating cartridges can be optional.

[0056] A further preferred embodiment of the forming device comprises a fluid unit for effecting a flow of a tempering fluid contained in two or more cavities of the cooling unit, wherein the control device is configured to control the fluid unit in such a way that between two successive tempering periods the tempering fluid is exchanged for a tempering fluid of lower temperature, so that rapid cooling of the first tempering unit and / or the second tempering unit is enabled.

[0057] Preferably, the fluid unit is fluidically coupled to a fluid container in which the fluid, in particular the low-temperature temperature control fluid, is stored. Furthermore, the fluid container can be designed to temperature-control, in particular to cool, the temperature control fluid. It is preferred that the temperature control fluid is provided in a central section of the cooling unit and flows from the central section in a star-shaped pattern toward an outer section. Between two consecutive temperature control periods can also mean that at the end of one temperature control period or at the beginning of another temperature control period, the temperature control fluid is exchanged for the low-temperature temperature control fluid.

[0058] A further preferred embodiment of the forming device comprises a process chamber surrounded by a wall, in which the first station and the second station are arranged, a transfer opening within the wall for introducing and / or removing the transfer unit into or from the process chamber, a movable lock element for opening and closing the transfer opening, which can be guided along the wall, wherein a volume-controllable sealing element acts between the wall and the lock element.

[0059] With the volume-controllable sealing element, the process chamber can be sealed more securely, reducing or preventing nitrogen loss and oxygen ingress to reduce mold wear.

[0060] The volume-controllable sealing element can, for example, be designed to be inflatable. In particular, it is preferred that the sealing element has an interior space that is fluidically coupled to a fluid supply unit, so that a sealing fluid can be introduced into the sealing element to inflate it. This has the advantage that, when the transfer opening is closed, the sealing element has a high volume and thus securely closes the transfer opening. When the transfer opening is opened, for example, by moving the lock element, the volume-controllable sealing element can have a low volume in order to reduce or prevent wear on the sealing element.

[0061] A further preferred development of the forming device is characterized in that it comprises a fastening plate which can be coupled to the transfer unit, wherein a press stamp which can be coupled to the fastening plate has a cavity for effecting a pressing force, through which a cooling fluid can flow in order to cool the press stamp.

[0062] The coupling between the transfer unit and the mounting plate can be achieved, for example, by arranging the transfer unit on the mounting plate. A cooled press ram has the advantage of reduced thermal displacement. Furthermore, sealing surfaces are less likely to be damaged.

[0063] In particular, it is preferred that a cooling sleeve is arranged within the cavity of the press ram, so that a cooling fluid can be introduced into the cavity through the cooling sleeve and can be discharged again at one end of the cavity.

[0064] In a further preferred embodiment of the forming device, it comprises an electric motor coupled to the mounting plate and / or the press ram, which generates the pressing force. In the prior art, the pressing force is typically provided by a pneumatic cylinder. An electric motor, particularly a servomotor, allows the pressing force to be precisely and variably adjusted. For example, a defined pressing force can be applied depending on the position of the press ram.

[0065] It is further preferred that the forming device comprises a feed unit arranged and configured to move the transfer unit from the first station to the second station. The feed unit preferably comprises an electric motor for moving the transfer unit.

[0066] According to a further aspect, the object mentioned at the outset is achieved by a method for forming, preferably for isothermal forming, a glass blank, in particular a volume blank and / or a thin glass, comprising the steps of: tempering a transfer unit holding the glass blank with a tempering unit within a tempering time period to a predefined temperature, wherein the glass blank is movable with the transfer unit from a first station to a second station, and setting the tempering unit with a tempering process parameter which is changed within the tempering time period such that the transfer unit can be tempered with a predefined temperature profile.

[0067] It is preferred that at a start time of the temperature control period, a first initial temperature of the first temperature control unit and / or a second initial temperature of the second temperature control unit is set. Furthermore, it is preferred that at an end time of the temperature control period, a first target temperature of the first temperature control unit and / or a second target temperature of the second temperature control unit is set. Furthermore, for heating, it is preferred that the first initial temperature is lower than the first target temperature and / or the second initial temperature is lower than the second target temperature. Furthermore, for cooling, it is preferred that the first initial temperature is higher than the first target temperature and / or the second initial temperature is higher than the second target temperature.

[0068] It is preferred that a first P-value is set in a first time period of the tempering period and a second P-value is set in a second time period of the tempering period following the first time period, wherein the second P-value is higher than the first P-value.

[0069] It is preferred that the predefined temperature is dependent on a point in time within the tempering period. It is preferred that the tempering process parameter is set such that in a first time period of the tempering period the temperature rises or falls with a first temperature gradient and in a second time period of the tempering period following the first time period the temperature rises or falls with a second temperature gradient, wherein the second temperature gradient is greater than the first temperature gradient. The fact that the second temperature gradient is greater than the first temperature gradient is to be understood in particular in terms of its absolute value, so that this applies to both heating and cooling. In the case of heating, in particular before forming, the temperature generally rises. In the case of cooling, in particular after forming, the temperature generally falls.

[0070] Furthermore, it is preferred that the tempering process parameter is set such that in a first time period of the tempering period, the tempering pressure has a first pressure value and in a second time period following the first time period, the tempering pressure has a second pressure value, wherein the second pressure value is greater than the first pressure value.

[0071] It is preferred that the heating elements are controlled such that the first temperature control unit and / or the second temperature control unit have a predefined temperature distribution. Furthermore, it is preferred that the first temperature control unit and / or the second temperature control unit are cooled.

[0072] It is preferred that, in a first time period of the tempering period, a core of the first tempering unit and / or the second tempering unit is heated more strongly than an outer section surrounding the core, so that heat is transported from the core into the outer section. Furthermore, it is preferred that, in a second time period of the tempering period following the first time period, the core is cooled by the cooling unit, so that heat is transported from the outer section of the transfer unit, and cooling of the first tempering unit and / or the second tempering unit is ensured after the tempering period has elapsed.

[0073] It is preferred that between two consecutive tempering periods, a tempering fluid of the cooling unit is exchanged for a tempering fluid of lower temperature, so that rapid cooling of the first tempering unit and / or the second tempering unit is enabled.

[0074] For further advantages, design variants and details of the individual aspects and their possible further training, please refer to the description of the other aspects, the corresponding features and further training.

[0075] Preferred embodiments are explained by way of example with reference to the accompanying figures. Figure 1 shows a schematic, two-dimensional view of an exemplary

[0076] Embodiment of a forming device;

[0077] Figure 2: a schematic, two-dimensional view of another exemplary embodiment of a forming device;

[0078] Figure 3: a schematic, two-dimensional view of an exemplary

[0079] Design of a heating unit;

[0080] Figure 4: a schematic, two-dimensional view of an exemplary

[0081] Design of a cooling unit;

[0082] Figure 5: a schematic, two-dimensional view of an exemplary

[0083] Embodiment of a first transfer opening;

[0084] Figure 6: a further schematic, two-dimensional view of an exemplary embodiment of a first transfer opening;

[0085] Figure 7: a schematic, two-dimensional view of a pressing unit;

[0086] Figure 8: a schematic, two-dimensional view of an exemplary embodiment of a press piston;

[0087] Figure 9: a schematic, two-dimensional view of a

[0088] feed unit;

[0089] Figure 10: another schematic, two-dimensional view of a

[0090] feed unit;

[0091] Figure 11 : a schematic, two-dimensional view of an exemplary

[0092] Embodiment of a temperature control unit; and

[0093] Figure 12: a schematic view of an exemplary process.

[0094] In the figures, identical or essentially functionally identical or similar elements are designated by the same reference numerals.

[0095] Figures 1 and 2 show a forming device 1 in whose process chamber 2 a first station 4, a second station 5, a third station 6, and a fourth station 8 are arranged. The forming device 1 comprises a first transfer opening 10, through which the transfer units 28 enter the process chamber 2. The first transfer opening 10 can be closed with a first lock element 12, which is arranged so as to be movable in the vertical direction in order to release the first transfer opening 10. Furthermore, the forming device 1 has the second transfer opening 14, through which the transfer units 28 can be led out of the process chamber 2 again. The second transfer opening 14 can be opened and closed with the second lock element 16.

[0096] At each station 4-8, a respective tempering unit 18, 38, 40, 42 is arranged. The tempering units 18, 38-42 are arranged and configured to temper a transfer unit 28 holding the glass blank 36 to a predefined temperature within a tempering period. In particular, the first station 4 and the second station 5 are provided for heating the glass blank 36. For this purpose, they are arranged and heated on a tempering surface of the tempering units 18, 38-42 with the transfer unit 28 designed as a mold. The tempering unit 18 is shown with a lower tempering unit 18a and an upper tempering unit 18b. The other tempering units 38-42 can also have upper tempering units in an analogous manner.

[0097] The control device 134 is signal-coupled to the temperature control units 18, 38-42. The control device 134 is configured to adjust the temperature control units 18, 38-42 using a temperature control process parameter. The temperature control process parameter can be, for example, a P value. Furthermore, the temperature control process parameter can be a temperature of the transfer unit 28 or the glass blank 36. Furthermore, the temperature control process parameter can be a temperature control pressure.

[0098] The control device 134 is further configured to change the tempering process parameter within the tempering time period such that the transfer unit 28 can be tempered with a predefined temperature profile.

[0099] To advantageously enable such a temperature profile, the first temperature control unit 18, analogous to the further temperature control units 38-42, has a heating unit 20 and heating elements 22, for example heating cartridges, embedded therein. Furthermore, the first temperature control unit 18 comprises an insulating plate 24 and a cooling unit 26. The heating unit 20 forms, among other things, the temperature control surface on which the transfer unit 28 can be arranged during normal temperature control operation. The insulating plate 24 is arranged between the cooling unit 26 and the heating unit 20. The transfer unit 28 has a lower mold 30 and an upper mold 32. Furthermore, a centering sleeve 34 is provided around the mold 30, 32. In addition, a further handling sleeve (not shown) is usually provided around the centering sleeve.

[0100] Alternatively to this embodiment, the insulating plate 24 may not be provided and instead only the heating unit 20 and the cooling unit 26 may be provided. In particular, the cooling unit 26 may form the tempering surface and the heating unit 20 may be arranged on a surface of the cooling unit 26 arranged opposite the tempering surface, so that the heat transfer from the heating unit 20 to the transfer unit 28 takes place through the cooling unit.

[0101] The forming device 1 shown in Figure 1 features transfer units 28 for forming glass blanks designed as volume blanks. In Figure 2, the transfer unit 28 is designed for forming thin glass and has the lower mold 30' and the upper mold 32' for this purpose.

[0102] Figure 3 shows a detailed view of the heating unit 20. The heating unit 20 comprises a heating plate 54. Heating cartridges 56 are embedded in the heating plate 54. As an alternative to the embedded heating cartridges 56, heating channels 58 can be embedded in the heating plate 54, through which, for example, a thermal oil flows. A heating ring 60 is arranged adjacent to an outer edge of the heating plate 54. The heating ring 60 can be designed either in the shape of a heating cartridge or as a heating channel through which a thermal oil flows. With such a heating unit 20, the transfer unit 28 can be advantageously temperature-controlled, since this enables a particularly homogeneous heat provision. In particular, the heating ring 60 offers better heat distribution, since the edge regions of heating plates 54 are usually cooler.

[0103] Figure 4 shows a detailed view of a preferred embodiment of a cooling unit 26. The cooling unit 26 comprises a cooling plate 48, which has a central coolant inlet 50 and cooling channels 52 extending in a star shape from the coolant inlet 50. A cooling channel 53 simulating the outer contour of the cooling plate 48 is provided around the star-shaped cooling channels 52. Such a cooling unit 26 has the advantage that a cold cooling fluid can be provided through the central coolant inlet 50 even before the end of the temperature control period. However, with appropriate control, this cooling fluid only flows slowly towards the outer cooling channel 53. This makes it possible for the cooling unit 26 to cool the inner core of the cooling plate 48 even before the end of the temperature control period, while the transfer unit 28 arranged on the cooling plate 48 continues to be heated.

[0104] Figure 5 shows a detailed illustration of the first transfer opening 10 with the first lock element 12. The first transfer opening 10 is arranged within a process chamber wall 62 of the process chamber 2. The first lock element 12 is guided on the process chamber wall 62 by means of a first guide rail 64 and a second guide rail 66. The first lock element 12 has a first sealing recess 68 and a second sealing recess 72. The sealing recesses 68, 72 can be designed as a groove and preferably form a circumferential groove. Volume-controllable sealing elements 70, 74 are arranged in the sealing recesses 68, 72. A single volume-controllable sealing element can also be arranged, which can, for example, be arranged circumferentially as shown in Figure 6.

[0105] Since the first lock element 12 opens and closes once with each cycle, wear on the seals is typically high. The first volume-controllable sealing element 70 and the second volume-controllable sealing element 74 are therefore designed to be inflatable. For clarity, the first volume-controllable sealing element 70 is shown in the deflated state and the second volume-controllable sealing element 74 is shown in the inflated state. It is shown that the second volume-controllable sealing element 74 forms a tight connection between the lock element 12 and the process chamber wall 62.

[0106] Figure 7 shows a forming unit, which is usually arranged outside the process chamber 2 and whose press piston 46 passes through the process chamber wall 62 and can act there on the transfer unit 28 or the mold by means of the mounting plate 44. The forming unit has an electric motor 86, which can be designed, for example, as a servomotor. The electric motor 86 is connected to a threaded spindle 84 and, above this, to a spindle nut 88. The spindle nut 88 is positively connected to the hollow shaft 90, so that by rotating the threaded spindle 84, the spindle nut 88 can be moved up or down. This also allows the hollow shaft 90 to move vertically. The hollow shaft 90 is in turn coupled to the guide carriage 76. The guide carriage 76 is guided by a first linear guide 78 and a second linear guide 80, so that it can be moved vertically with high precision.The guide carriage 76 is connected to the press piston 46. The electric motor 86 and the linear guides 78, 80 are arranged on the frame 82 of the forming unit.

[0107] Figure 8 shows a preferred embodiment of the press piston 46. This comprises a piston housing 92 having a hollow space. The fluid sleeve 94, which has a fluid inlet 96, is arranged in this hollow space. Thus, a fluid can flow through the fluid inlet 102 into the fluid inlet 96. The length of the fluid sleeve 94 is selected such that it leaves a gap between the outlet and the bottom of the piston housing. Thus, at this end, the fluid can exit the fluid sleeve 94 and flow into the hollow space or fluid outlet 98 of the piston housing 92. From there, it can flow out through the fluid outlet 100. This enables a press piston 46 that is continuously cooled, so that the high temperatures in the process chamber 2 do not lead to any expansion and / or deformation of the press piston 46 that could disrupt the process.

[0108] Figures 9 and 10 show a feed unit 104, which is arranged and designed to move the transfer unit 28 through the process chamber 2 from one station to the next station. The feed unit 104 comprises an electric motor 106 which is mechanically coupled to a threaded spindle 114 by means of a coupling 108. The threaded spindle 114 is mounted on bearing blocks 110, 116. Furthermore, a spindle nut 112 is arranged on the threaded spindle 114. The spindle nut 112 is connected in the translational direction to a connecting element 126. The connecting element 126 is in turn rotatably coupled to a feed rod 122 via a bearing block 120. A rotary movement of the threaded spindle 114 thus causes a feed movement 124 of the linear guide rail 118. The transfer unit 28 can thus be moved through the process chamber 2.

[0109] Figure 11 shows a possible embodiment of a temperature control unit 18. The temperature control unit comprises the heating unit 20 with heating elements 22, an insulating plate 24, and the cooling unit 26. The unit, consisting of the heating unit 20, insulating plate 24, and cooling unit 26, is connected to the mounting plate 44 via threaded rods 138. During normal operation, the transfer unit 28 is arranged below the heating unit 20. By a vertical downward movement of the press piston 46 in Figure 11, a force is exerted on the transfer unit 28, so that the upper cavity of the transfer unit 28 is pressed downward, and the glass blank 36 is formed.

[0110] Figure 12 shows a schematic process. In step 200, a transfer unit 28 holding the glass blank 36 is tempered to a predefined temperature by a tempering unit 18, 38-42 within a tempering period. Between two consecutive tempering periods, the glass blank 36 is moved by the transfer unit 28 from the first station 4 to the second station 5.

[0111] In step 202, the temperature control unit 18, 38-42 is set with a temperature control process parameter, which is changed within the temperature control period such that the transfer unit 28 is temperature-controlled according to a predefined temperature profile. Setting the transfer unit 28 can also be a control and / or regulation process.

[0112] The forming device 1 described above and the corresponding method enable better forming of glass blanks 36. The improvement lies in particular in the fact that the temperature control units 18, 38-42 are not set to a fixed temperature, but rather the temperature control of the transfer unit 28 is adjustable. REFERENCE SYMBOL

[0113] Forming device

[0114] Process chamber first station second station third station fourth station first transfer opening first lock element second transfer opening second lock element first temperature control unit heating unit heating element insulation plate cooling unit

[0115] Transfer unit, 30' lower mold, 32' upper mold

[0116] Centering sleeve

[0117] Glass blank second tempering unit third tempering unit fourth tempering unit mounting plate

[0118] Plunger

[0119] Cooling plate

[0120] Coolant inlet, 53 cooling channel

[0121] heating plate

[0122] Heating cartridge

[0123] Heating duct

[0124] Heating ring

[0125] Process chamber wall first guide rail second guide rail first sealing recess first volume-controllable sealing element second sealing recess second volume-controllable sealing element

[0126] Guide carriage first linear guide second linear guide

[0127] frame

[0128] threaded spindle

[0129] electric motor

[0130] spindle nut

[0131] Hollow shaft 2 piston housing

[0132] 94 Fluid sleeve

[0133] 96 Fluid inlet

[0134] 98 Fluid drain

[0135] 100 fluid outlet

[0136] 102 Fluid inlet

[0137] 104 feed unit

[0138] 106 Electric motor

[0139] 108 Clutch

[0140] 110 bearing block

[0141] 112 spindle nut

[0142] 114 Threaded spindle

[0143] 116 bearing block

[0144] 118 Linear guide rail

[0145] 120 bearing block

[0146] 122 push rod

[0147] 124 Feed direction

[0148] 126 connecting element

[0149] 128 base plate

[0150] 130 linear guide carriages

[0151] 132 fixed bearings

[0152] 134 Control device

[0153] 136 fitting screws

[0154] 138 threaded rods

Claims

CLAIMS Forming device (1) for forming a glass blank (36), comprising a first station (4) and a second station (5, 6, 8) for tempering and / or forming the glass blank (36), wherein the first station (4) has a first tempering unit (18) and / or the second station (5, 6, 8) has a second tempering unit (38-42), which are arranged and designed to temper a transfer unit (28) holding the glass blank (36) to a predefined temperature within a tempering time period, a control device (134) which is signal-coupled to the first tempering unit (18) and / or the second tempering unit (38-42) and which is designed to set the first tempering unit (18) and / or the second tempering unit (38-42) with a tempering process parameter, wherein the control device (134) is designed to To change tempering process parameters within the tempering time period in such a way,that the transfer unit (28) can be tempered with a predefined temperature profile. Forming device (1) according to claim 1, wherein the control device (134) is configured to set the tempering process parameter such that, at a start time of the tempering period, a first initial temperature of the first tempering unit (18) and / or a second initial temperature of the second tempering unit (38-42) can be set, and at an end time of the tempering period, a first target temperature of the first tempering unit (18) and / or a second target temperature of the second tempering unit (38-42) can be set, wherein, for heating the glass blank, the first initial temperature is lower than the first target temperature and / or the second initial temperature is lower than the second target temperature, and / or, wherein for cooling the glass blank the first initial temperature is higher than the first target temperature and / or the second initial temperature is higher than the second target temperature.

3. Forming device (1) according to one of the preceding claims, wherein the control device (134) has a controller unit and the tempering process parameter is a P parameter of the controller unit, in a first time segment of the tempering period the controller unit has a first P value and in a second time segment of the tempering period following the first time segment the controller unit has a second P value, and the second P value is higher than the first P value.

4. Forming device (1) according to one of the preceding claims, wherein the tempering process parameter relates to a temperature of the transfer unit (28) and / or a tempering element acting on the glass blank (36), wherein the predefined temperature is dependent on a point in time within the tempering period, and / or the tempering process parameter relates to a tempering pressure with which the tempering element acts on the glass blank (36), wherein the tempering pressure is dependent on a point in time within the tempering period.

5. Forming device (1) according to one of the preceding claims, wherein the control device (134) is arranged such that the tempering process parameter is set such that in a first time period of the tempering period, the temperature rises or falls with a first temperature gradient and in a second time period of the tempering period following the first time period, the temperature rises or falls with a second temperature gradient, wherein the second Temperature gradient is greater than the first temperature gradient, and / or the tempering process parameter is set such that in a first time period of the tempering period the tempering pressure has a first pressure value and in a second time period following the first time period the tempering pressure has a second pressure value, wherein the second pressure value is greater than the first pressure value.

6. Forming device (1) according to one of the preceding claims, wherein the first temperature control unit (18) and / or the second temperature control unit (38-42) has heating elements (56, 58) that can be controlled separately by the control device (134), and the control device (134) is configured to control the heating elements (56, 58) such that the first temperature control unit (18) and / or the second temperature control unit (38-42) has or have a predefined temperature distribution.

7. Forming device (1) according to one of the preceding claims, wherein the first tempering unit (18) and / or the second tempering unit (38-42) has a cooling unit (26) which is arranged and designed to cool the first tempering unit (18) and / or the second tempering unit (38-42).

8. Forming device (1) according to one of the preceding claims, wherein the control device (134) is configured to heat a core of the first temperature control unit (18) and / or the second temperature control unit (38-42) more strongly in a first time period of the temperature control period than an outer section surrounding the core, so that the heat is transported from the core into the outer section in order to avoid a thermal shock, and / or the control device (134) is configured to cool the core with the cooling unit in a second time period of the temperature control period following the first time period, so that heat is transported from the outer section to the transfer unit (28) is transported and after the tempering period has elapsed, cooling of the first tempering unit (18) and / or the second tempering unit (38-42) is ensured.

9. Forming device (1) according to one of the preceding claims, wherein the first tempering unit (18) and / or the second tempering unit (38-42) has a heating unit (20), and preferably the heating unit (20) and the cooling unit (26) are formed integrally, wherein the transfer unit can be arranged on the cooling unit so that heat provided by the heating unit is transferred through the cooling unit to the transfer unit.

10. Forming device (1) according to one of the preceding claims, wherein the heating unit (20) has an upper side for arranging the transfer unit (28) and one or the heating element (56, 58) is arranged on an underside of the heating unit (20) facing away from the upper side.

11. Forming device (1) according to one of the preceding claims, wherein a heat-conducting intermediate layer (24) is arranged between the cooling unit (26) and the heating unit in order to conduct heat to the transfer unit (28) during normal operation.

12. Forming device (1) according to one of the preceding claims, wherein the heating unit (20) has two or more heating elements (56, 58) which are at least partially enclosed by a heating ring (60).

13. Forming device (1) according to one of the preceding claims, comprising a fluid unit for effecting a flow of a tempering fluid contained in two or more cavities (52, 53) of the cooling unit (26), wherein the control device (134) is designed to control the fluid unit in such a way that between two successive tempering periods the tempering fluid is exchanged for a tempering fluid of lower temperature, so that a rapid Cooling of the first temperature control unit (18) and / or the second temperature control unit (38-42) is made possible. Device (1) according to one of the preceding claims, comprising a process chamber (2) surrounded by a wall (62), in which the first station (4) and the second station (5, 6, 8) are arranged, a transfer opening (10, 14) within the wall (62) for introducing and / or removing the transfer unit (28) into or from the process chamber (2), a movable lock element (12, 16) for opening and closing the transfer opening (10, 14), which can be guided along the wall (62), wherein a volume-controllable sealing element (70, 74) acts between the wall (62) and the lock element (12, 16).Device (1) according to one of the preceding claims, comprising a fastening plate (44) which can be coupled to the transfer unit (28), wherein a press die (46) which can be coupled to the fastening plate for effecting a pressing force has a cavity (98) through which a cooling fluid can flow in order to cool the press die. Device (1) according to one of the preceding claims, comprising an electric motor (86) which is coupled to the fastening plate and / or the press die and which generates the pressing force. Device for forming a glass blank (36), comprising the steps: Tempering a transfer unit (28) holding the glass blank (36) with a tempering unit (18) within a tempering period to a predefined temperature, wherein the glass blank (36) can be moved with the transfer unit (28) from a first station to a second station, and setting the tempering unit (18) with a tempering process parameter which is changed within the tempering period such that the transfer unit (28) can be tempered with a predefined temperature profile.

Images