DE102018117208A1 - Process, tool module and system for forming flat workpieces - Google Patents

Abstract

Method for shaping flat workpieces, in whicha) a shaping die (5, 23) arranged in a tool module (1, 28, 41) is heated to a shaping die preheating temperature, b) the workpiece (26, 37) outside one intended for the shaping process Forming furnace (35) is heated to a workpiece preheating temperature, c) the workpiece (26, 37) is introduced into the forming furnace (35), the forming furnace (35) having a higher temperature than the preheated one, at least in a forming furnace area provided for the forming process Workpiece (26, 37), d) in the forming furnace (35) the workpiece (26, 37) is heated to a forming temperature at a distance from the forming die (5, 23), the distance being increased by a relative to the forming die (5, 23) movable holding device arranged on the tool module is defined, e) the workpiece (26, 37) is lowered to the forming die (5, 23) by means of the holding device after the forming temperature has been reached, and f) then the factory A tool module for forming flat workpieces with a forming die (5, 23) has a holding device for a workpiece (26, 37) and means for moving the holding device relative to the forming die (5, 23) A system for forming flat workpieces with several tool modules (1, 28, 41) and forming furnaces (35) is also proposed.

Description

The invention relates to a method for forming flat workpieces, a tool module according to the preamble of claim 8 and a system for forming flat workpieces.

The flat workpieces can be thin glass, for example, which is used in a wide variety of areas, for example for vehicle glazing in the interior or exterior of vehicles, displays, also head-up displays, controls, covers for controls, as components of Mobile phones, in medical technology or optics. Complex three-dimensional shapes are often required as a result of the reshaping.

For the forming process, the workpiece is brought to a temperature that allows the forming and e.g. formed by pressing, gravity bending or vacuum in a mold. Forming by means of vacuum, possibly also combined with other force-exerting measures, has proven to be advantageous for achieving complex three-dimensional geometries with high dimensional accuracy, high aspect ratios and / or small bending radii with thin wall thicknesses.

From the EP 2724992 A1 a method and a system for forming flat workpieces are known, with which an automated mass production should be possible. For this purpose, a large number of form matrices are arranged on a rotary table. Using a robot, raw workpieces are placed on a molding die. Before the raw workpieces are placed on them, they can be preheated in a separate device. Due to the rotation of the rotary table, the form matrices are guided through a large number of heat transfer modules. In successive heat transfer modules, the workpiece is gradually heated further, this time together with the forming die, until a sufficient temperature is reached for the forming. A vacuum is then applied so that the forming can take place under isothermal conditions. By isothermal conditions it is meant that the workpiece and the tool, ie the molding die, have essentially the same temperature. After the forming, the workpiece and the die are passed through further heat transfer modules, in which a controlled cooling takes place. After passing through the heat transfer modules, the finished formed workpieces are automated, for example by means of a robot arm, the rotary table and thus the mold dies. To support the detachment of the finished formed workpiece from the associated forming die, gas can be introduced into the forming die to generate an overpressure. The associated molding die can be cooled by means of a plate-shaped cooling device, for example. In the isothermal process given here, the temperature of the molding die is essentially the same at the time the workpiece temperature is deformed. The high temperature of the mold die leads to higher tool wear compared to lower temperatures. In the case of isothermal processes, an annealing process for the workpiece usually takes place after the shaping on the molding die, which leads to correspondingly high mold loading times.

From the EP 2307325 B1 Methods and a system for forming thin glass and a tool module of the type mentioned at the outset are known, where the thin glass is heated by means of radiation in such a way that its temperature is at least 100 ° C. higher than the temperature of the shaping surface of the molding die. This can be achieved by heating the thin glass lying on the molding die in a targeted manner to the temperature desired for the shaping with infrared radiators within a few minutes, so that the shaping surface of the molding die only reaches a lower temperature until the shaping. The temperature difference should be advantageous for the quality of the surface of the molded glass. The disclosed tool module consists of a molding die and devices for applying a vacuum to carry out vacuum-assisted forming. To achieve a higher throughput, it is proposed to use several molding dies simultaneously in the same forming furnace. A correspondingly large furnace space is required for this.

The invention is based on the technical problem of providing a method, a tool module and a system of the type mentioned at the outset which can accelerate the forming process and make it more efficient. The technical problem is solved with regard to the method with the features of claim 1, with regard to the tool module with the characterizing features of claim 8 and with regard to the system with the features of claim 15.

Advantageous embodiments of the method, the tool module and the system result from the dependent claims.

Thus, in a method for forming flat workpieces, it is proposed that a molding die arranged in a tool module is heated to a molding die preheating temperature, the workpiece is heated to a workpiece preheating temperature outside a forming furnace provided for the forming process, which Workpiece is introduced into the forming furnace, the forming furnace having a higher temperature than the preheated workpiece at least in a forming furnace area intended for the forming process, in the forming furnace the workpiece is heated to a forming temperature at a distance from the forming die, the distance being movable by a distance relative to the forming die and the holding device arranged on the tool module is defined, the workpiece is lowered onto the forming die by means of the holding device after the forming temperature has been reached, and the workpiece is then formed.

The peculiarity of the proposed method consists, on the one hand, in that the workpiece preheated outside the forming furnace to a workpiece preheating temperature is introduced into the forming furnace, the forming furnace area having a higher temperature, preferably at least the forming temperature, than that, at least in a forming furnace area intended for the forming process has preheated workpiece. In this way it is avoided that the workpiece has to be completely heated from ambient temperature to the forming temperature in the forming furnace, which would increase the occupancy time of the forming furnace and thus the process time.

On the other hand, further heating of the workpiece takes place within the forming furnace, which is preferably at a temperature in the region of the forming temperature, when the workpiece is introduced, thereby accelerating the further heating of the workpiece due to the unnecessary heating of the molding matrix mass.

The shaping furnace preferably already has the temperature required for the shaping process, at least in a region provided for the shaping process, so that the shaping furnace itself does not have to be warmed up together with the workpiece, as is usually the case with isothermal chamber processes.

By means of the distance between the workpiece and the forming die, which is generated by means of the holding device, even when the workpiece and the forming die are located together in the forming furnace, the temperature of the workpiece and the forming die for forming under non-isothermal conditions are different.

Opposite the one from the EP 2 307 325 B1 Known non-isothermal processes are proposed for the first time to preheat the workpiece and the tool module outside the forming furnace, so that the heating process within the forming furnace can also be significantly shortened here.

In the case of a workpiece made of glass, the preheating is preferably carried out in such a way that the workpiece preheating temperature of the glass is at least 100 ° C., more preferably at least 70 ° C. to a maximum of preferably 50 ° C. below the respective glass transition temperature of the glass.

The method according to the invention can also be carried out in such a way that the workpiece lying on the holding device or on the molding die is heated to the workpiece preheating temperature. In this variant, the tool module is also outside the forming furnace while the workpiece is being heated to the workpiece preheating temperature.

The mold can be preheated to the mold preheat temperature at the same time. Workpiece preheating temperature and mold die preheating temperature can also be largely the same, for example by introducing the tool module with the workpiece lying thereon into a preheating furnace. However, the workpiece preheating temperature and the mold die preheating temperature can also be different within the preheating furnace, e.g. because an isothermal temperature distribution within the preheating furnace is not set. Different preheating temperatures for the workpiece and the die can also be easily achieved by setting a distance between the workpiece and the die using the holding device, e.g. by placing the workpiece on the holding device which is at least partially extended or at least partially extending the holding device after placing the workpiece on it,

It is also conceivable that the temperature of the molding die, depending on the previous application, is higher than the desired molding die preheating temperature. In this case, it may make sense to cool the mold die to reach the mold die preheating temperature. This can also take place when the workpiece has already been introduced into the tool module, in particular if the workpiece is placed at a distance from the molding die by means of the holding device.

The method according to the invention can be carried out in such a way that vacuum is used for the forming process. By means of the vacuum with which the workpiece is drawn into the forming die, forming with small radii can be achieved, in particular in the case of thin workpieces, for example in the case of thin glass. The vacuum can be the only measure for reshaping or have a supporting effect, for example in addition to lowering gravity or to use overpressure or a stamp device on the opposite side.

Provision can be made to keep the workpiece for a certain period of time in the area of the forming temperature after the forming in order to relax, in the case of glasses generally above the transition temperature. This is done with the workpiece resting on the form die. The time period can be at least 10 seconds and at most 1 minute, preferably at most 30 seconds, in particular in connection with thin glass as a workpiece.

After forming and, if necessary, after relaxing, the tool module is removed from the forming furnace together with the workpiece. The first cooling step for the workpiece can preferably be effected by actively cooling the molding die. The active cooling takes place, for example, by means of a fluid, preferably compressed air, which is blown into the vacuum area of the molding die. The workpiece is cooled by the compressed air and ideally raised from the die. For this purpose, a possibly existing hold-down device, which is shown below, has already been removed from the workpiece.

Furthermore, the method according to the invention can be carried out in such a way that the workpiece is lifted off the molding die after the shaping process by means of the holding device. This may take place after the workpiece has cooled to a temperature which offers sufficient strength for the workpiece to be lifted off. The lifted workpiece then cools down further.

The entire process can be visual and / or metrological, e.g. via volume flow and / or temperature measurement

Insofar as the workpiece is cooled on the lifted workpiece, the influence of the molding die on the cooling process is reduced. In particular, the cooling time of the workpiece can be reduced as a result. In addition, a potentially harmful influence of different coefficients of thermal expansion of the workpiece and the die is eliminated. Another advantage of reducing the contact time between the workpiece and the die can be less wear on the die. It is also not necessary to cool the mold die to the temperature desired for the formed workpiece, which is why energy can be saved for a subsequent process.

The method according to the invention can also be carried out in such a way that the molding die for the forming process is heated to a lower temperature than the workpiece, the temperature difference preferably being at least 30 ° C. and at most 250 ° C. This results in a non-isothermal process which, as a rule, has shorter process times compared to isothermal processes, since smaller masses have to be heated to the temperature desired for the forming. This also protects the form die.

Furthermore, the method according to the invention can be carried out in such a way that a plurality of forming furnaces are provided, which are loaded one after the other from a loading station with at least one preheated workpiece. The preheated workpiece can already be located in the tool module or can be inserted into the tool module that is already in the respective forming furnace.

For this purpose it can be provided that the forming furnaces are moved relative to the loading station, preferably with a rotary table device. In this case, an unloading station can also be provided which removes the formed workpiece from the tool module remaining in the forming furnace or the tool module together with the formed workpiece from the respective forming furnace. In this way, the process can be rationalized and automated with a high throughput. The loading station can also have a preheating unit that preheats the workpiece or the tool module together with the workpiece.

In the case of a tool module of the type mentioned at the outset, it is proposed that the tool module have a holding device for a workpiece to be formed and means for moving the holding device relative to the molding die. The workpiece can thus be placed on the molding die by the holding device arranged on the tool module. Separate devices outside the tool module, such as a robot arm is therefore not absolutely necessary to ensure a distance between the workpiece and the die during heating. The same applies to the lifting of the workpiece, which can also be done by the holding device, e.g. for the cooling process and / or for preparing the removal of the workpiece from the tool module.

The tool module according to the invention can also be designed such that the holding device has a plurality of pin-like elements. The contact area between the holding device and the workpiece can thus be minimized. The number of pins can be selected such that an optimal compromise between the smallest possible contact area and sufficient support is achieved, for example to minimize one inadvertent bending of the workpiece between the pins due to a reduced strength of the workpiece during heating. However, it can also make sense to provide at least one element for the holding device which is not pin-shaped, for example a wall-like element with a continuous, preferably narrow or sharp upper edge on which the workpiece rests. Sharp-edged elements - especially in combination with a hold-down device - can also be used to create predetermined breaking points in the workpiece. Such predetermined breaking points can be useful for removing marginal areas that are not required for the end product. However, the holding device can also have a combination of differently shaped elements.

Furthermore, the tool module according to the invention can be designed such that the tool module has at least one cooling unit and / or at least one heating unit. This cooling unit and / or the heating unit can e.g. serve the form matrix. The workpiece resting on the holding device can be heated in the forming furnace, e.g. by means of infrared radiation, while the molding die is simultaneously cooled via the cooling unit to ensure the desired temperature difference between the workpiece and the molding die. The heating unit can also be used to regulate or control the temperature of an element of the tool module, e.g. the mold die, for example when setting the mold die preheating temperature.

Furthermore, the tool module according to the invention can be designed in such a way that a position insert, which is arranged underneath the molding die and provides the positioning of the molding die, is provided. The position insert is preferably interchangeable and thus also enables the use of different form matrices in the tool module. The position insert and any elements arranged on or in it have a long service life. The material to be exchanged can be limited to the elementary parts of the die. In addition, the layer insert can be designed such that it also serves as a homogenizing element for the homogenization of the temperature distribution in the molding die. In addition, at least one bushing for fluid or as a vacuum line or at least part of a vacuum distribution chamber can be formed in the position insert. The position insert can also act as a cooling unit and / or heating unit, so that a separate cooling unit or a separate heating unit can be dispensed with.

The tool module according to the invention can also be designed such that the mold die has at least one exchange opening, e.g. in the form of an implementation, for exchanging an active medium, in particular for generating a vacuum.

Furthermore, the tool module according to the invention can be designed such that the tool module has a hold-down device that can be moved relative to the forming die for holding down a workpiece to be formed on the forming die. Such a hold-down device prevents the flowing of workpiece edges into the mold die and the formation of folds in the edge area during the forming process. The formation of folds can have an undesired influence on the shape of the workpiece and, in the case of vacuum-assisted forming, can also lead to leaks which can hinder the forming process.

The hold-down device on the tool module is an alternative to a hold-down device fixed to a forming furnace, against which the workpiece would have to be pressed via the tool module. Hold-down devices attached to the metal-forming furnace have the disadvantage that they quickly decompose due to the high temperatures that occur in the process and the fact that they remain permanently in the metal-forming furnace, and they often have to be replaced as wearing parts. A hold-down device arranged on the molding tool is regularly moved out of the furnace chamber, and may therefore have a longer service life or may also be more easily accessible for replacement.

If the hold-down device is arranged on the tool module, the same forming furnace can be used for different tool modules and thus different workpiece shapes. It is then not necessary to replace a holding-down device fixed in the forming furnace for different workpiece shapes.

The tool module according to the invention can also be designed such that the hold-down device can be controlled in its position and / or its orientation relative to the molding die, in particular by means of at least one gas pressure spring. In an open, for example raised, position or arrangement, there is the possibility of placing the workpiece on the holding device, while in a closed, for example lowered, position or arrangement, the workpiece is pressed onto the molding die. The hold-down device itself or means for changing the position and / or arrangement of the hold-down device can be elastic elements, e.g. Springs, to make the effect on the workpiece as gentle as possible. The pressing force of the hold-down device on the workpiece can preferably be regulated.

With regard to the system of the type mentioned in the introduction, it is proposed that at least two tool modules, at least two Forming furnaces and at least one loading station set up for loading the forming furnaces with workpieces and at least one removal station set up for removing formed workpieces from the forming furnaces are provided, the forming furnaces preferably being movable by means of a conveying element relative to the loading station and / or to the unloading station.

The workpieces can e.g. with suitable gripping and moving units, inserted into the tool modules already located in the forming furnaces at the loading stations and removed from the tool modules at the unloading stations. However, it is also possible to insert the tool modules together with at least one workpiece each into the forming furnaces at the loading stations and to remove them from the forming furnaces at the unloading stations. The respective workpiece or the respective tool module together with the workpiece can be supplied with pretreatments, e.g. preheating before the workpiece or the workpiece is moved into the forming furnace together with the tool module or at least with a part of the tool module.

The conveyor element can e.g. a conveyor belt, but preferably a rotary table on which the forming furnaces are arranged. It can be provided that the shaping furnaces are arranged to be movable on the conveying element relative to the conveying element, so that the shaping furnaces e.g. can be moved relative to the associated tool module positioned on the conveyor element, for example in order to achieve an optimal effect of the temperature distribution generated in the respective forming furnace. The forming furnaces can be lockable furnaces with a door or open forming furnaces into which the workpieces or the tool modules can be inserted without a door mechanism.

The system according to the invention can also have at least one preheating unit different from the forming furnaces, e.g. in the loading station or in close proximity to the loading station.

The tool module is preferably designed to be movable relative to the shaping furnace, preferably horizontally and vertically, in order to move in and out of the shaping furnace and preferably from below into the shaping furnace. A travel unit can be provided for this.

Exemplary embodiments of the method according to the invention, the tool module according to the invention and the system according to the invention are explained below with reference to figures.

• 1: ein Werkzeugmodul in perspektivischer Ansicht,
• 2: das Werkzeugmodul nach 1 im Querschnitt mit ausgefahrenen Stiften,
• 3: das Werkzeugmodul nach 1 im Querschnitt mit eingezogenen Stiften,
• 4: eine Formmatrize mit Werkstück und Niederhalter
• 5: das Werkzeugmodul nach 1 mit auf Stiften aufgelegtem Werkstück,
• 6: das Werkzeugmodul nach 1 ergänzt mit Werkstück und verfahrbarem Niederhalter und
• 7: eine Rundtischanlage.

It shows schematically

• 1 : a tool module in perspective view,
• 2 : the tool module after 1 in cross section with extended pins,
• 3 : the tool module after 1 in cross section with retracted pins,
• 4 : a form die with workpiece and hold-down device
• 5 : the tool module after 1 with workpiece placed on pins,
• 6 : the tool module after 1 supplemented with workpiece and movable hold-down and
• 7 : a rotary table system.

1 shows schematically a perspective view of a tool module 1 with a base plate 2 , a top 3 of the tool module 1 and between the base plate 2 and the top 3 arranged column elements 4 , The pillar elements 4 ensure a sufficient distance between the base plate 2 and possibly elements arranged thereon or therein for the hot area of the forming furnace.

2 shows the tool module 1 according to 1 in a cross section and an interrupted view through which the column elements 4 are only abbreviated. The top 3 includes a form die 5 , a location mission 6 , a, for example plate-shaped, heating unit 7 and a, for example plate-shaped, cooling unit 8th , Through the cooling unit 8th , the heating unit 7 , the location use 6 and the form die 5 four pin-like elements, hereinafter referred to as pins, are used as a holding device for a workpiece not shown here 9 referred to, performed relative to other elements of the tool module 1 are movable. The representation of the 2 the pencils 9 here all on a connecting plate 10 fixed and stand over this connecting plate 10 as well as a support beam 11 with a lifting cylinder 12 in connection. By means of this lifting cylinder 12 can the pens 9 relative to the other elements of the tool module 1 be moved. The pencils 9 are in 2 shown in the extended state, so one on the pins 9 placed workpiece (in 2 not shown) the form die 5 would not touch.

In the top 3 become form matrix 5 , Location use 6 , Heating unit 7 and cooling unit 8th using bolts 13 (please refer 2 ) fixed to each other with a pre-tension, so that a sufficiently thermally conductive contact between these elements is guaranteed and possibly the elements of the upper part 3 flowing fluid lines are tight. The Bolts are through holes 15 performed, as shown in 1 in recesses 14 lead.

The heating unit 7 has heating grooves 16 and the cooling unit 8th cooling grooves 17 in which, for example, heating elements or cooling elements can be guided. The heating or cooling elements can be fluids or other temperature control elements, such as electrical heating loops. The heating can thus be resistance heating or can also be carried out inductively or by means of a heating fluid or by a combination of different heating methods. The grooves are depending on the tempering method 16 or 17 not required, for example if the heating unit is concerned 7 around induction loops are provided. It is also possible to use the form die 5 to be heated directly, for example by induction, so that on the heating unit 7 can be dispensed with. It is also conceivable on heating unit 7 and / or cooling unit 8th and / or use of position 6 not to be used, for example if the temperature control is from outside the tool module 1 arranged means can be achieved.

The form die 5 has bushings 18 on which the deepening 19 the form die 5 with a distribution chamber 20 connect, some in the form die 5 and partly in the field 6 is formed. The distribution chamber 20 is via a vacuum line 21 with a vacuum connection 22 connected, which is intended for connection to a vacuum pump, for example. Using the vacuum line 21 , the distribution chamber 20 and the bushings 18 can with a workpiece (in 1 to 3 not shown) a negative pressure is generated with which the heated workpiece for the purpose of forming in the recess 19 can be drawn in. The vacuum can also be applied to the surface of the recess with a single one 19 the form die 5 running vacuum line or by some other alternative arrangement.

3 shows the tool module 1 in the representation according to 2 , but with retracted pens 9 , A workpiece that is also not shown here and that is lying on top would immediately form the die 5 touch. Except for the position of the pens 9 are the 2 and 3 identical, which is why due to the description of the individual elements to the explanations 2 is referred.

4 shows a second die 23 in a sectional perspective view, the second mold die 23 a single one to a deepening 24 leading vacuum line 25 having. The second form die 23 should also belong to a tool module that is not shown here in its entirety. On the second mold die 23 is a workpiece 26 , for example a thin glass, which is fitted with a hold-down device 27 on the second die 23 is held down. This prevents edge areas of the workpiece 26 during the forming process, which is caused, for example, by a vacuum in the recess 24 can be effected or at least supported, in the deepening 24 flow into or be drawn into. The hold-down 27 can be fixed to a forming furnace, not shown here, so that the second form die 23 in such a way, for example through an access from below, that the workpiece must be guided into the forming furnace 26 in the right position to hold down 27 arrives. As shown later, the hold-down can also be from 4 Tool module, not shown, are held and be part of the same.

5 shows the tool module 1 as shown in 2 with extended pins 9 , but with the workpiece resting on it 26 after reshaping. The shape of the workpiece 26 is on the surface shape of the mold 5 customized. After forming the workpiece 26 by means of the pens 9 from the form die 5 lifted off, eg around the workpiece 26 separate from the form die 5 cool down and / or to remove the workpiece 26 to facilitate. The other elements of the tool module 1 are opposite 2 unchanged, which is why reference is made to the relevant description.

6 shows a second tool module 28 , which is the structure of the tool module 1 according to the 1 to 3 corresponds, but with a movable hold-down device 29 is added. The hold-down 29 is from through the base plate 2 guided hold-down bars 30 worn by those in 6 two are shown, but the number can also be higher. The hold-down bars 30 are in turn on a cross member 31 supported, which can be plate-shaped, for example, and via a base plate 33 embedded second lifting cylinder 32 in height relative to the form die 5 is movable. With the hold-down device raised 29 can the workpiece 26 on the pens 9 (in 6 however already in the retracted state). Has the workpiece 26 the pins reach the desired temperature for the forming 9 shut down until the workpiece 26 on the form die 5 rests. Then the hold-down device 29 drove down until it was on the workpiece 26 rests and this on the form matrix 5 presses, preferably with regulated force. This is the situation in 6 is shown. Because of the other elements of the second tool module 28 will refer to the description of the 1 to 3 directed.

The forming process can then be carried out. After the forming process, the hold-down is 29 raised the workpiece 26 pre-cooled by means of compressed air blown in via the vacuum system and from the molding die 5 solved by means of the pins 9 further from the form die 5 lifted off and cooled to a desired extent. The cooling can take place in the forming furnace or preferably outside the forming furnace, not shown here. After that, the workpiece 26 from the second workpiece module 28 removed or together with the second workpiece module 28 be subjected to further treatment.

The shape of the hold-down 29 or the means for moving the hold-down device 29 can of course also be selected differently, for example to remove or place the workpiece 26 to facilitate. A laterally movable and / or laterally foldable, possibly divisible hold-down device can be used.

The following is an exemplary forming process using the second tool module 28 according to 6 presented. First the workpiece 26 in a preheating unit, not shown here, preheated separately to a first temperature and then with the hold-down device raised 29 on the raised pins 9 of the preheated tool module 28 hung up. The preheating temperature of the workpiece 26 is preferably only just below the forming temperature. Preheating the second tool module 28 , especially the form die 5 , usually to a significantly lower temperature than the preheating temperature of the workpiece 26 , can, for example, with the on the tool module 28 existing heating unit 7 can be achieved. Alternatively, the form die 5 along with that on the pens 9 resting workpiece 26 be heated in the preheater.

The workpiece brought to preheating temperature 26 is together with the second tool module 28 introduced into a forming furnace, also not shown here, in which this continues on the extended pins 9 resting workpiece 26 is heated to the forming temperature, for example by means of infrared radiation. By taking suitable measures, for example by using the cooling unit 8th , the mold die is achieved 5 the forming temperature has not been reached and a desired temperature difference between the workpiece 26 and form die 5 of eg 100 ° C remains. Depending on the materials involved, the temperature difference is to be selected so that, on the one hand, the workpiece is glued 26 on the form die 5 is prevented, which is usually at too high temperatures of the mold 5 happens, and on the other hand a cooling of the workpiece, which disturbs the forming 26 is avoided. With thin glass as a workpiece 26 experience shows that a sensible temperature difference can be between 40 ° C and 200 ° C, for example.

Is the forming temperature in the workpiece 26 the pins are reached 9 lowered until the workpiece 26 on the form die 5 rests. At the same time the hold-down 29 lowered so that the workpiece 26 is fixed. Via the vacuum line 21 , the distribution chamber 20 and the implementations 18 will in the deepening 19 the form die 5 creates a vacuum which, together with gravity if necessary, deforms the workpiece 26 causes. The workpiece hugs the surface of the form die 5 until the forming process is completed.

After the forming process is complete, the workpiece can be 26 to relax a certain time in the range of the forming temperature. Then the workpiece 26 in the form die 5 be actively cooled, for example indirectly via the forming die 5 by means of the cooling unit 7 and / or by blowing a fluid, for example compressed air, between the molding die 5 and formed workpiece 26 , The fluid becomes the workpiece 26 with the hold-down device raised 29 from the form die 5 lifted. As soon as the workpiece has achieved sufficient strength, or in the case of thin glass, an adequate viscosity value, the workpiece becomes 26 by means of the pens 9 further from the form die 5 lifted off in order to be able to cool further at a distance from it.

The second tool module is preferably immediately after the forming or, if appropriate, after the relaxation 28 removed from the forming furnace, and the formed workpiece 26 can cool further, for example when passing through a cooling furnace, not shown here, by convection of the workpiece 26 surrounding atmosphere or by blowing cooling gas through the vacuum channels 18 ,

After cooling, the workpiece can 26 from the second tool module 28 are removed, and the second tool module 28 Another forming process is available, due to the modularity of the tool module 28 if necessary, the form die 5 and / or at least one of its other elements can be easily replaced.

With the tool module 28 , as with any other tool module, which is relative to the form die 5 movable pins 9 or another relative to the form die 5 movable holding device, a considerable degree of automation and a time and thus cost savings can also be achieved for forming into complex three-dimensional shapes. By preheating outside the forming furnace and thus using the forming furnace solely for increasing the workpiece temperature from the workpiece preheating temperature to the forming temperature and the Forming process itself, the cycle rate can be increased significantly. By means of the holding device, for example in the form of the pins 9 , given distance between workpiece 26 and form die 5 it takes less time to heat up to the forming temperature and to cool down later. In particular, the mold must be used for the cooling process 5 not on that for the workpiece 26 desired temperature are cooled. Rather, the form die 5 are kept at a higher temperature, which is closer to or even corresponds to the die preheating temperature desired for the next forming process, so that a separate preheating for the die can then at least partially be omitted.

7 shows a purely schematic representation of a rotary table system with a rotary table 34 , on the example of six forming furnaces 35 are arranged. Via a preheating oven 36 a loading station 42 become workpieces 37 preheated to a workpiece preheating temperature and by means of a first conveyor 38 the rotary table 34 fed and if necessary with transfer means, not shown here, in each of the forming furnaces 35 spent. In the forming furnaces shown here by way of example as open units, ie without a door mechanism 35 there are only symbolically shown tool modules here 41 into which the workpieces 37 by means not explicitly shown, for example gripping elements, preferably on elements already extended, for example pins 9 (please refer 2 . 3 . 5 and 6 ), the holding devices. With the tool modules 41 can be, for example, those as described above by way of example. The form die 5 can in the associated forming furnace 35 be heated to the mold die preheating temperature, the heating unit and / or the cooling unit of the tool module also being used to adjust the mold die preheating temperature, if present 41 can be used.

The first conveyor 38 can be kept very short to keep temperature loss on the way low. The conveyor 38 can have a conveyor belt or alternative means such as a robotic arm.

After loading one of the forming furnaces 35 becomes the rotary table 35 relative to the preheating furnace 36 twisted to the next forming furnace 35 to position for loading. The forming furnaces 37 have in their interior, at least in a forming area, a temperature which is sufficient, the preheated one and at a distance from the molding die 5 workpiece 37 to bring to the forming temperature. The temperature increase of the workpiece 37 and the forming of the workpiece 37 , for example with the method steps described above, optionally also relaxing the workpiece 37 , preferably take place on the way of the respective forming furnace 35 to an unloading position in which the tool module contained therein 37 together with the formed workpiece from the forming furnace 35 removed and via a second conveyor 40 an unloading station 39 can be supplied. A cooling process can be carried out in the unloading station.

The forming furnaces 35 are on over web elements 44 one, here exemplary star-shaped, forming furnace holding device 43 fixed. The web elements 44 can be controlled in length to change the forming furnaces 35 relative to the rotary table 34 to be able to proceed. This makes it possible to position the forming furnaces relative to the respective tool module 41 to adjust.

LIST OF REFERENCE NUMBERS

1

tool module

2

baseplate

3

top

4

pillar member

5

forming die

6

able use

7

heating unit

8th

cooling unit

9

pen

10

connecting plate

11

shore

12

lifting cylinder

13

bolts

14

recess

15

bolt head

16

heating groove

17

cooling groove

18

bushings

19

deepening

20

distribution chamber

21

vacuum line

22

vacuum connection

23

Second form die

24

deepening

25

vacuum line

26

workpiece

27

down device

28

Second tool module

29

down device

30

Hold-down bar

31

crossmember

32

Second lifting cylinder

33

baseplate

34

roundtable

35

Umformofen

36

Preheating oven

37

workpiece

38

First funding agency

39

unloading

40

Second conveyor

41

tool module

42

loading

43

Umformofen holder

44

web element

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2724992 A1 [0004]
• EP 2307325 B1 [0005, 0013]

Claims (17)

Process for forming flat workpieces, in which a) a molding die (5, 23) arranged in a tool module (1, 28, 41) is heated to a molding die preheating temperature, b) the workpiece (26, 37) is heated to a workpiece preheating temperature outside a forming furnace (35) provided for the forming process, c) the workpiece (26, 37) is introduced into the shaping furnace (35), the shaping furnace (35) having a higher temperature than the preheated workpiece (26, 37) at least in a shaping furnace area provided for the shaping process, d) in the forming furnace (35) the workpiece (26, 37) is heated to a forming temperature at a distance from the forming die (5, 23), the distance being defined by a holding device which can be moved relative to the forming die (5, 23) and is arranged on the tool module . e) the workpiece (26, 37) is lowered to the molding die (5, 23) after the forming temperature has been reached, and f) the workpiece (26, 37) is then formed. Procedure according to Claim 1 , characterized in that the workpiece (26, 37) on the holding device or on the molding die (5, 23) is heated to the workpiece preheating temperature. Method according to one of the preceding claims, characterized in that vacuum is used for the forming process. Method according to one of the preceding claims, characterized in that the workpiece (26, 37) is cooled outside the forming furnace (35). Method according to one of the preceding claims, characterized in that the workpiece (26, 37) is lifted off the molding die (5, 23) by means of the holding device after the shaping process. Method according to one of the preceding claims, characterized in that the forming die (5, 23) for the forming process is heated to a lower temperature than the workpiece (26, 37), the temperature difference preferably being at least 30 ° C and at most 250 ° C , Method according to one of the preceding claims, characterized in that a plurality of forming furnaces (35) are provided, which are loaded one after the other by a loading station with at least one preheated workpiece (26, 37). Tool module for forming flat workpieces with a forming die (5, 23), characterized in that the tool module (1, 28, 41) has a holding device for a workpiece to be formed (26, 37) and means for moving the holding device relative to the forming die (5, 23). 23). Tool module after Claim 8 , characterized in that the holding device has a plurality of pin-like elements (9). Tool module after Claim 8 or 9 characterized in that the tool module (1, 28, 41) has at least one cooling unit (8) and / or at least one heating unit (7). Tool module according to one of the Claims 8 to 10 , characterized in that a position insert (6) is provided underneath the molding die (5, 23) and specifies the positioning of the molding die (5, 23). Tool module according to one of the Claims 8 to 11 , characterized in that the molding die (5, 23) has at least one exchange opening (18) for exchanging an active medium, in particular for generating a vacuum. Tool module according to one of the Claims 8 to 12 , characterized in that the tool module (1, 28, 41) has a hold-down device (27, 29) which can be moved relative to the forming die (5, 23) for holding down a workpiece (26, 37) to be reshaped onto the forming die (5, 23). Tool module after Claim 13 , characterized in that the hold-down device (27, 29) can be controlled in its position and / or its orientation relative to the molding die (5, 23), in particular by means of at least one gas pressure spring. System for forming flat workpieces, comprising at least two tool modules (1, 28, 41) according to one of the Claims 8 to 14 , at least two forming furnaces (35) and at least one loading station (42) set up for loading the forming furnaces (35) with workpieces (26, 37) and at least one removal station set up for removing formed workpieces (26, 37) from the forming furnaces (35) (39), the forming furnaces (35) preferably being movable relative to the loading station and / or to the unloading station (39) by means of a conveyor element (34). System according to Claim 15 , characterized by at least one preheating unit different from the forming furnaces (35). System according to Claim 15 or 16 , characterized in that at least one of the forming furnaces (35) is arranged on the conveyor element (34) and can be moved relative to the conveyor element (34).

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