EP4345209A1 - Moule et procédé de régulation de la répartition de température dans un moule pour produits tridimensionnels - Google Patents

Moule et procédé de régulation de la répartition de température dans un moule pour produits tridimensionnels Download PDF

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Publication number
EP4345209A1
EP4345209A1 EP23193793.9A EP23193793A EP4345209A1 EP 4345209 A1 EP4345209 A1 EP 4345209A1 EP 23193793 A EP23193793 A EP 23193793A EP 4345209 A1 EP4345209 A1 EP 4345209A1
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EP
European Patent Office
Prior art keywords
tool
heating
cavity
molding
heating element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23193793.9A
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German (de)
English (en)
Inventor
Martin Hahnemann
Raphael Köppl
Richard Hagenauer
Thomas Schickmaier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kiefel GmbH
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Kiefel GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kiefel GmbH filed Critical Kiefel GmbH
Publication of EP4345209A1 publication Critical patent/EP4345209A1/fr
Pending legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J3/00—Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21J—FIBREBOARD; MANUFACTURE OF ARTICLES FROM CELLULOSIC FIBROUS SUSPENSIONS OR FROM PAPIER-MACHE
    • D21J3/00—Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds
    • D21J3/10—Manufacture of articles by pressing wet fibre pulp, or papier-mâché, between moulds of hollow bodies

Definitions

  • a mold for producing three-dimensional products from a fiber-containing material and a method for controlling a temperature distribution in a mold for producing three-dimensional products are described.
  • Fibrous materials are increasingly being used to produce, for example, packaging for food (e.g. bowls, capsules, boxes, etc.) and consumer goods (e.g. electronic devices, etc.) as well as beverage containers. Everyday objects such as disposable cutlery and tableware are also made from fibrous materials. Fibrous materials include natural fibers or artificial fibers. Recently, fibrous materials have been increasingly used that contain natural fibers or consist of fibers that can be obtained from renewable raw materials or waste paper, for example. The natural fibers are mixed in a so-called pulp with water and, if necessary, other additives such as starch. Additives can also have an effect on the color, barrier properties and mechanical properties. This pulp can contain, for example, 0.1 to 10% by weight of natural fibers. The proportion of natural fibers varies depending on the process used to produce packaging, etc., and the product properties of the product to be manufactured.
  • a fiber processing facility has several stations or forming stations.
  • a forming station for example, fibers can be sucked into a cavity of a suction tool , whereby a preform is shaped or formed.
  • the pulp is provided in a pulp supply and the suction tool with at least one suction cavity, the geometry of which essentially corresponds to the product to be manufactured, is at least partially immersed in the pulp.
  • suction takes place via openings in the suction cavity which are connected to a corresponding suction device, with fibers from the pulp collecting on the surface of the suction cavity.
  • the sucked-in fibers or a preform can then be brought via the suction tool into a pre-pressing tool, whereby the preform is pre-pressed. During this pre-pressing process, the fibers in the preform are pressed and the water content of the preform is reduced.
  • preforms can be provided by scooping, whereby a scooping tool is dipped into the pulp and fibers are deposited on molded parts of the scooping tool when it is raised.
  • the preforms are then pressed into finished products in a hot press.
  • preforms are introduced into a hot pressing tool, which, for example, has a lower tool half and an upper tool half that are heated.
  • the preforms are pressed in a cavity with heat input, with residual moisture being released by the pressure and heat, so that the moisture content of the preforms is reduced from approx. 60% by weight before hot pressing to, for example, 5-10% by weight. % is reduced after hot pressing.
  • the water vapor created during hot pressing is extracted during hot pressing through openings in the cavities and channels in the hot pressing tool.
  • a hot-pressing tool and a manufacturing process using the hot-pressing process described above are known, for example, from EN 10 2019 127 562 A1 known.
  • a control system for heating tool plates fails when the surface temperature of the mold surfaces is measured, because this drops sharply cyclically due to contact with moist material and water. It should also be noted that the heat energy stored in the tool plates and also in the cavities and molded parts "continues to flow".
  • the surface temperatures on the mold surfaces of cavities and molded parts can depend on other, different factors. For example, the number of molding devices per tool plate, the tool material or material pairing, the material used for the preforms, their moisture content, the heat storage capacity of the molding devices, etc.
  • the task is to provide a uniform temperature distribution on the molding surfaces of molding devices of a molding tool, especially for products with large mold depths. Furthermore, the task is to provide an alternative to the state of the art and to ensure improved production for a large number of different product geometries.
  • a molding tool for producing three-dimensional products from a fiber-containing material having at least a first tool component and at least a second tool component, the first tool component and the second tool component each having a tool body, the tool body of the first tool component having at least a cavity and the tool body of the second tool component has at least one molded part corresponding to the at least one cavity, wherein the at least one molded part and the at least one cavity can be moved relative to one another and for pressing to form a mold space between corresponding surfaces of the at least one cavity and the at least one molded part a fibrous material that can be introduced into the mold space can be pressed, and wherein the first tool component and / or the second tool component have at least one heating device, wherein the at least one heating device is arranged such that due to the arrangement of the at least one heating device, at least a first heating circuit in the tool body and at least one second heating circuit is formed in the associated at least one cavity or the at least one molded part.
  • the temperatures in the tool body and an associated cavity or molded part can be individually regulated in order to achieve an optimal temperature for the manufacturing process, without tool components being heated too much or too little to achieve an average temperature which represents a compromise.
  • different temperatures can be achieved in a tool body and the associated at least one mold device (cavity or molded part), whereby basic heating can take place via the tool plate, for example in the range of 200 to 300°C.
  • a tool plate can be heated to around 250 °C.
  • the heating of the at least one mold device (cavity or molded part) can take place, for example, in the range of 170 to 250 °C. If the tool plate is heated to 250 °C, the mold devices can be heated to 220 °C, for example.
  • the basic heating of the tool body can also be maintained in standby mode, for example.
  • the molding devices themselves can be brought to a lower or higher temperature, which is sufficiently high for the hot pressing process.
  • the temperature of the basic heating is adapted to the required hot-pressing temperature on the mold surfaces, so that the "continuing flow" of heat from the tool body does not lead to an increase in the surface temperature or the surface temperature on the surfaces of the mold surfaces does not exceed the required hot-pressing temperature ( e.g. 220 °C).
  • the temperature of the molding devices can be higher, such as a base heating system in a tool body, whereby a "continued flow" of heat from the molding devices into a tool body does not usually occur, since thermal energy is cyclically extracted from the molding devices by the evaporation of water stored in the fibrous material.
  • the prevailing temperature difference can essentially compensate for the loss of thermal energy when water evaporates.
  • the at least one heating device can have at least one heating element which is arranged asymmetrically in the tool body and in the associated at least one cavity or molded part.
  • An asymmetrical arrangement occurs, for example, when a heating element designed as a heating cartridge lies largely in the tool body, with a small portion protruding into the molding device.
  • the molding devices cavities, molded parts
  • the recordings must always be adapted to the arrangement and design of the corresponding heating device.
  • a symmetrical arrangement of the at least one heating device can be provided, whereby an individual temperature distribution can be achieved according to the design and arrangement within a tool body and the molding devices.
  • An individual temperature distribution can be achieved, for example, via the distance of a heating element to a surface or molding area.
  • a "continued flow" of heat at larger distances between a heating element and a molding surface in a molding device can lead to the surface temperature being lower than in a design with a smaller distance.
  • the temperature distribution in a tool body is also different to the temperature distribution in the molding devices, so that in these embodiments an individual temperature setting in the components of the molding tool can also be achieved by a symmetrical arrangement.
  • an effective heating surface of the at least one heating element can have a larger area within the tool body than an area within the associated at least one cavity or mold part, so that a larger heat transfer takes place in the tool body, or an effective heating surface of the at least one heating element can have a larger area within at least one cavity or mold part than an area within the tool body, so that a larger heat transfer takes place in the mold devices, which are cyclically cooled by the evaporation of water.
  • a heating element can have at least two heating zones, which can provide different heating and are arranged accordingly so that a first heating zone in the tool body and a second heating zone are arranged in an associated molding device.
  • the at least one heating device can have at least one first heating element and at least one second heating element, the at least one first heating element being arranged in the tool body and the at least one second heating element being arranged in the associated at least one cavity or molded part.
  • the first heating element and the second heating element can be separate heating elements that can be controlled independently of one another and can provide heating that differs from one another in order to generate different temperatures in a tool body and at least one associated molding device.
  • the at least one first heating element is part of the first heating circuit and the at least one second heating element is part of the second heating circuit.
  • a mold can have a plurality of cavities and associated molded parts, with heating elements of the at least one heating device being arranged differently with respect to position and/or orientation to one another and/or to the associated cavities or molded parts.
  • the position and orientation can, for example, relate to the alignment and the distance to surfaces of the tool body and the mold surfaces.
  • At least one heating element of at least one heating device for a cavity or molded part can be arranged and/or controlled differently than at least one heating element of at least one heating device for another cavity or molded part of a first tool component and/or a second tool component. This not only allows different heating of tool bodies and associated molding devices, but also allows individual molding devices to be heated differently than other molding devices of an associated tool body. In addition, zones of a tool body can also be heated differently.
  • the at least one first heating element and the at least one second heating element can have different heating outputs due to their design.
  • heating elements can have heating surfaces of different sizes and different heating outputs.
  • a molding tool can additionally have at least one cooling device, wherein the temperature of the molding tool, in particular of the at least one tool body, can be regulated during operation between a standby temperature and a maximum production temperature of a production temperature range via the at least one heating device and the at least one cooling device, wherein the standby temperature is lower than a minimum production temperature.
  • the molding tool can have at least one sensor element for detecting the temperature of the tool body and/or the at least one molding device (cavity, molded part) in order to control the at least one heating device in accordance with the detected temperature.
  • at least one sensor element can be provided which detects the surface temperature of the molding surfaces of the at least one molding device.
  • the arrangement/orientation of the at least one heating device and heating elements as well as their control for heating the corresponding components can be determined in advance in a simulation.
  • the mold is then formed based on the optimal arrangement determined.
  • the above-mentioned object is also achieved by a method for controlling a temperature distribution in a mold for producing three-dimensional products from a fibrous material, wherein preforms are pressed into products under pressure and temperature in the mold, wherein the mold has at least one first tool component and at least one second tool component, wherein the first tool component and the second tool component each have a tool body, wherein the tool body of the first tool component has at least one cavity and the tool body of the second tool component has at least one molded part corresponding to the at least one cavity, wherein the at least one molded part and the at least one cavity are moved relative to one another to form a mold space between corresponding surfaces of the at least one cavity and the at least one molded part and are pressed to form a fibrous material that can be introduced into the mold space, wherein the first tool component and/or the second tool component have at least one heating device, wherein at least one first heating circuit in the tool body and at least one second heating circuit in the associated at least one cavity or the at least one molded part are formed
  • the temperature can be individually controlled and regulated.
  • the individual regulation or control means that the temperatures can be specified and set independently of one another.
  • the surface temperature of the mold surfaces drops due to contact with moist fibrous material and the evaporation of water.
  • the surface temperature can drop by approx. 100 to 130 °C, e.g. 120 °C.
  • the direct heating, independent of the tool body, via, for example, a separate heating element in the at least one mold device enables rapid reheating to the extent actually required, whereby the mold device is not heated higher than, for example, an optimal hot pressing temperature determined in advance.
  • the advantage of faster heating is achieved compared to known Designs in which only one heater is provided via a tool body are achieved in that the heat from the tool body does not have to "flow in" first, but is provided directly via the first heating device in the mold device.
  • the at least one heating device can have at least one first heating element and at least one second heating element and the at least one first heating element can be arranged in the tool body and the at least one second heating element can be arranged in the associated at least one cavity or molded part, the temperature in the tool body and the temperature in the at least one associated cavity or the at least one associated molding can be individually regulated via the at least one first heating element and the at least one second heating element.
  • the at least one first heating element and the at least one second heating element can, for example, be heated differently.
  • the heating of the tool body of the first tool component and/or the second tool component and the associated at least one cavity or the at least one molded part can be individually regulated with regard to the temperature and heating duration provided via the at least one first heating element and the at least one second heating element.
  • the heating temperature can be set and adjusted differently, but the heating duration can also be adjusted. This can, for example, prevent molding devices from overheating if the hot-pressing process is briefly interrupted or a standby mode is activated in which no hot-pressing takes place and therefore no cooling of the molding surfaces takes place.
  • several cavities and/or mold parts of the second heating circuit assigned to a tool body can be heated differently in order to take individual heat requirements into account and to achieve the optimum temperature on the mold surfaces.
  • the molding devices influence each other thermally depending on their position on the tool body and their design, so that, for example, different heating is required for molding devices on the edge than for molding devices in a middle position on the tool body.
  • a temperature distribution is regulated in a mold for three-dimensional products, in particular products made of a fiber-containing material, with preforms being pressed under pressure into finished products in the mold, the mold having at least two molding devices [cavity and molding] and at least two heating devices has, wherein the at least two heating devices can be controlled differently to achieve a definable temperature distribution on mold surfaces of the at least two molding devices and / or the distance of a heating device of the at least two heating devices to at least one assigned molding surface of a molding device is larger or smaller than the distance of a further heating device at least two heating devices for at least one assigned molding surface of a further molding device.
  • control and thus the heating of the at least one heating device or heating elements can be different from one another and/or the heating elements can be at an unequal distance from the mold surfaces assigned to them. This means that with identical heating devices that cannot, for example, be controlled or heated differently, a desired temperature distribution can be achieved via the distance of the heating devices from the mold surfaces.
  • the heating devices can - additionally or alternatively - be controlled or heated differently so that a uniform temperature distribution is achieved on the molding surfaces of the molding devices. In particular, this can ensure that all molding surfaces of a molding tool are in a definable temperature range.
  • Molding devices can, for example, be designed as positive and/or negative of the products to be manufactured and protrude into a tool plate of the molding tool or protrude from a tool plate. To form products, negatives and positives of the molding devices are brought together so that cavities form between them.
  • the arrangement and orientation of heating elements can also be deliberately chosen so that there is a non-homogeneous heat distribution on the surfaces of molding surfaces, for example in order to take into account the material thickness in products with different thickness sections and therefore the correspondingly lower or higher heat requirement.
  • Fig. 1 shows a schematic representation of a fiber processing device 1000 for producing three-dimensional products from a fiber-containing material.
  • the fiber-containing material for the production of molded parts is processed in a pulp basin 200 of the fiber processing device 1000.
  • a pulp basin 200 of the fiber processing device 1000 for example, water and fibers and, if necessary, additives can be introduced into a pulp basin 200 via a liquid supply and the pulp in the pulp basin 200 can be processed by mixing the individual components with heat and aids, such as a stirrer.
  • Pulp is an aqueous solution that contains fibers, whereby the fiber content of the aqueous solution can be in a range of 0.1 to 10% by weight. It can also contain additives such as starch, chemical additives, wax, etc.
  • the fibers can be natural fibers such as cellulose fibers or fibers from a fiber-containing original material (e.g. waste paper).
  • a fiber processing plant offers the possibility of processing pulp in large quantities and making it available to several fiber processing facilities 1000.
  • the fiber processing device 1000 can be used to produce, for example, biodegradable cups 3000 and other products that have great heights (> 50mm). Since a fibrous pulp with natural fibers is used as the starting material for the products, the products produced in this way can themselves be used as starting material for the production of such products after their use or can be composted because they can generally be completely decomposed and do not contain any harmful, environmentally hazardous substances.
  • the fiber processing device 1000 shown has a frame 100, which can be surrounded by a casing.
  • the supply units 300 of the fiber processing device 1000 comprise, for example, interfaces for the supply of Media (e.g. water, pulp, compressed air, gas, etc.) and energy (power supply), a central control unit 310, at least one suction device 320, line systems for the various media, pumps, valves, lines, sensors, measuring devices, a BUS system, etc. as well as interfaces for bidirectional communication via a wired and/or wireless data connection.
  • Media e.g. water, pulp, compressed air, gas, etc.
  • energy (power supply) energy (power supply)
  • a central control unit 310 at least one suction device 320
  • line systems for the various media, pumps, valves, lines, sensors, measuring devices, a BUS system, etc. as well as interfaces for bidirectional communication via a wired and/or wireless data connection.
  • a data connection via a fiber optic cable can also exist.
  • the data connection can exist, for example, between the control unit 310 and a central controller for several fiber processing devices 1000, to a fiber processing plant, to a service point and/or other devices.
  • the fiber processing device 1000 can also be controlled via a bidirectional data connection via a mobile device, such as a smartphone, tablet computer or the like.
  • the control unit 310 is in bidirectional communication with an HMI panel 700 via a BUS system or a data connection.
  • the HMI (Human Machine Interface) panel 700 has a display which displays operating data and states of the fiber processing device 1000 for selectable components or the entire fiber processing device 1000.
  • the display can be designed as a touch display, so that settings can be made manually by an operator of the fiber processing device 1000.
  • additional input means such as a keyboard, a joystick, a keypad, etc., can be provided on the HMI panel 700 for operator input. This can be used to change settings and influence the operation of the fiber processing device 1000.
  • the fiber processing device 1000 has a robot 500.
  • the robot 500 is designed as a so-called 6-axis robot and is therefore able to pick up, rotate and move parts in all spatial directions within its radius of action.
  • other handling devices can also be provided, which are designed to pick up products and twist or rotate them and move them in different spatial directions.
  • such a handling device can also be designed differently, for which purpose the arrangement of the corresponding stations Fiber processing device 1000 may differ from the exemplary embodiment shown.
  • a suction tool 520 is arranged on the robot 500.
  • the suction tool 520 has cavities formed as suction cavities as a negative of the three-dimensional molded parts to be formed, such as cups 3000.
  • the cavities can, for example, have a net-like surface on which fibers from the pulp are deposited during suction. Behind the net-like surfaces, the cavities are connected to a suction device via channels in the suction tool 520.
  • the suction device can be realized, for example, by a suction device 320. Pulp can be sucked in via the suction device if the suction tool 520 is located within the pulp basin 200 in such a way that the cavities are at least partially in the aqueous fiber solution, the pulp.
  • a vacuum or negative pressure for sucking fibers when the suction tool 520 is in the pulp basin 200 and the pulp can be provided via the suction device 320.
  • the fiber processing device 1000 has corresponding means in the supply units 300.
  • the suction tool 520 has lines for providing the vacuum/negative pressure from the suction device 320 in the supply units 300 to the suction tool 520 and the openings in the cavities. Valves are arranged in the lines, which can be controlled via the control unit 310 and thus regulate the suction of the fibers.
  • the suction device 320 can also “blow out” instead of suction, for which the suction device 320 is switched to a different operating mode according to its design.
  • the suction tool 520 When producing molded parts from a fiber material, the suction tool 520 is dipped into the pulp and a negative pressure/vacuum is applied to the openings of the cavities, so that fibers are sucked out of the pulp and, for example, attach themselves to the network of cavities of the suction tool 520.
  • the robot 500 then lifts the suction tool 520 out of the pulp basin 200 and moves it with the fibers adhering to the cavities, which still have a relatively high moisture content of, for example, over 80% by weight of water, to the pre-pressing station 400 of the fiber processing device 1000, The negative pressure in the cavities is maintained for transfer.
  • the pre-pressing station 400 has a pre-pressing tool pre-press molds.
  • the pre-press molds can, for example, be designed as positives of the molded parts to be produced and have an appropriate size with regard to the shape of the molded parts to accommodate the fibers adhering to the cavities.
  • the suction tool 520 with the fibers adhering to the cavities is moved to the pre-pressing station 400 in such a way that the fibers are pressed into the cavities.
  • the fibers in the cavities are pressed together, so that a stronger connection is created between the fibers.
  • the moisture content of the preforms formed from the sucked fibers is reduced, so that the preforms formed after pre-pressing only have a moisture content of, for example, 60% by weight.
  • flexible pre-pressing molds can be used, which are inflated, for example, using compressed air (process air) and thereby press the fibers against the wall of a cavity of another suction tool part. “Inflating” both presses out water and reduces the thickness of the sucked-in fiber layer.
  • liquid or pulp can be sucked out and returned via the suction tool 520 and/or via further openings in pre-pressing molds or tool parts (cavities).
  • the liquid or pulp emerging during suction via the suction tool 520 and/or during pre-pressing in the pre-pressing station 400 can be returned to the pulp basin 200 or a pulp processing facility.
  • the preforms produced in this way are moved on the suction tool 520 via the robot 500 to a hot-pressing station 600, which has a molding tool 610 for the final shaping and drying of the preforms into three-dimensional products.
  • a hot-pressing station 600 which has a molding tool 610 for the final shaping and drying of the preforms into three-dimensional products.
  • the negative pressure is maintained on the suction tool 520 so that the preforms remain in the cavities.
  • the preforms are transferred via the suction tool 520 to a lower tool body 622 of a first tool component of the molding tool 610, which can be moved along the production line from the hot-pressing station 600.
  • the suction tool 520 is moved to the lower tool body 622 so that the preforms can be placed on molding devices or molded parts 624 of the lower tool body 622. Subsequently, an overpressure is generated via the openings in the suction tool 520 so that the preforms are actively deposited from the cavities in the suction tool, or the suction is stopped so that the preforms remain on the mold devices or mold parts 624 of the lower tool body 622 due to gravity. By providing overpressure at the openings of the cavities of the suction tool, pre-pressed preforms that are resting/adhering to the cavities of the suction tool can be released and released.
  • the suction tool 520 is moved away from the robot 500 and the suction tool 520 is immersed into the pulp tank 200 to suck in further fibers for producing molded parts from fibrous material.
  • the lower tool body 622 of the molding tool 610 moves after the preforms have been transferred to the hot-pressing station 600.
  • the preforms are pressed into finished products under heat input and high pressure, for which purpose an upper tool body 632 of a second tool component 630 of the molding tool 610 via a Press is brought onto the lower tool body 622.
  • the upper tool body 632 has cavities 634 corresponding to the molding devices or molded parts 624.
  • the lower tool body 622 and the upper tool body 632 are moved relatively away from each other and the upper tool body 632 is moved along the fiber processing device 1000 in the production direction, with the manufactured products being sucked in via the upper tool body 632 after the hot pressing and thus remaining within the cavities.
  • the manufactured products are thus removed from the hot pressing station 600 and placed on a conveyor belt of a conveyor device 800 via the upper tool body 632 after the process. After depositing, the suction via the upper tool body 632 is stopped and the products remain on the conveyor belt. The upper tool body 632 moves back into the hot pressing station 600 and another hot pressing operation can be carried out.
  • the fiber processing device 1000 also has a conveyor device 800 with a conveyor belt. After the final shaping and hot pressing in the hot pressing station 600, the manufactured products made of fiber-containing material can be placed on the conveyor belt and removed from the fiber processing device 1000. In further versions, after placing the products on the Further processing takes place on the conveyor belt of the conveyor device 800, such as filling and/or stacking the products. Stacking can be done, for example, using an additional robot or another device.
  • the fiber processing device 1000 from Fig.1 shows a possible embodiment.
  • a fiber processing device according to the technical teaching described here can also have only one forming station with an exchangeable tool, for example a suction tool 520 or a hot-pressing tool in which fiber-containing material can be processed, wherein different tools for producing different three-dimensional products can be accommodated in the at least one forming station.
  • the other for the fiber processing device 1000 of Fig.1 The stations and devices shown are not absolutely necessary for the implementation of the technical teaching.
  • Fig. 2 shows a schematic representation of a mold 610 for hot pressing preforms made of a fiber-containing material according to the prior art.
  • the molding tool 610 has a first tool component 620 and a second tool component 630.
  • the first tool component 620 has a tool body 622 and the second tool component 630 has a tool body 632.
  • Molding devices are arranged on the mutually facing surfaces or connected to the tool bodies 622, 632.
  • molding devices designed as molded parts 624 are arranged on the surface of the tool body 622.
  • molding devices designed as cavities 634 are arranged, which are designed to correspond to the molded parts 624, so that in the closed state of the molding tool 610 there is a molding space between the surfaces of the molded parts 624 and the surfaces of the cavities 634 is trained.
  • the molding devices are interchangeably connected to the tool bodies 622, 632, so that various products can be produced with the molding tool 610 of a hot pressing station 600.
  • the molding devices can be connected to the tool bodies 622, 632 by means of screws.
  • a first heating element 625 is arranged in the tool body 622 and a first heating element 635 is arranged in the tool body 632.
  • the first heating elements 625 and 685 can be designed, for example, as heating cartridges.
  • the tool bodies 622, 632 and the associated molding devices are heated via the heating elements 625 and 635.
  • the components of the mold 610 consist of a heat-conducting material, such as aluminum.
  • the components of the molding tool 610 can have channels and openings for sucking in and sucking out water or steam that emerges when moist preforms are pressed (hot pressed).
  • the embodiment shown according to the prior art has the disadvantage that the heating of the mold 610 for a hot pressing process does not allow a demand-optimized temperature distribution.
  • the heat introduced via the first heating elements 625, 635 is distributed in the tool bodies 622, 632 and from there in the molding devices.
  • the heat transfer is therefore very slow and has several disadvantages.
  • the temperature on the surfaces of the molding devices only depends on the heat input provided by the heating elements 625, 635 and, on the other hand, a different power requirement, as is usually the case with molding tools with several molding devices ("multi-cavity" tool), cannot be taken into account so that the quality of the manufactured products and the cycle time of the hot pressing process suffer.
  • the requirements for the variability of the heating depending on the position of a molding device on a tool body 622, 632 increases with increasing height for large mold depths or product heights.
  • Fig. 3 shows a schematic representation of an embodiment of a tool component 620 of a mold 610 according to the technical teachings disclosed herein, which solves the problems of the prior art.
  • the first tool component 620 has at least one second heating element 626 for the molded parts 624, so the molded parts 624 can be heated directly via this and the temperature on the molded surfaces of the molded parts 624 can vary from the temperature of other molded parts 624.
  • basic heating of a tool body 622 can take place, as described at the beginning, which is necessary to maintain a gauge temperature and which provides basic heating, but the temperature of the molded parts 624 is lower or the same as the basic heating.
  • Such second heating elements 626 can be designed, for example, as heating cartridges.
  • the mold parts 624 and the tool body 622 can have channels have in which lines are accommodated.
  • the channels and connection points between channels in molded parts 624 and a tool body 622 can have insulation in further embodiments. Furthermore, these can be arranged in such a way that the load on such lines is minimized.
  • Fig. 4 shows a schematic representation of an embodiment of a mold 610 according to the technical teaching disclosed herein, wherein both the mold parts 624 and the cavities 634 have at least one second heating element 636, so that individual heating of the cavities 634 and the corresponding mold parts 624 can take place. In this case, individual heating can take place in particular depending on the position of the molding devices or the pairs of molding devices (cavity 634 and associated molding 624).
  • the cavities 634 have a plurality of second heating elements 636 which are arranged in an edge region.
  • cooling through the evaporation of water during hot pressing of moist preforms made of fibrous material can be counteracted, since the heat does not have to flow out of the tool body 632 as was previously the case in the prior art, but can be introduced directly into the mold surfaces or the heat flow is constant in the immediate vicinity of the cooled areas of the mold surfaces.
  • the basic heating of the tool bodies 622, 632 also prevents the heat-conducting components of the mold 610 from cooling down.
  • first heating elements 625, 635 are also arranged in the tool bodies 622, 632, so that the basic heating can also be adjusted locally.
  • Fig. 5 shows a schematic representation of a further embodiment of a tool component 620 of a mold 610 according to the technical teaching disclosed herein, wherein heating elements 627 are provided which have a first heating area 627A and a second heating area 627B.
  • the two heating areas 627A, 627B can be controlled differently and thus provide heating that differs from one another.
  • the molded parts 624 can have openings, for example. When connecting molded parts 624 to the associated one Tool body 622, the molded parts 624 with the openings can be placed on the protruding areas or heating areas 627B and then firmly connected to the tool body 622, for example by means of screws.
  • heating elements can be arranged in such a way that only part of their effective heating surface is accommodated in molding devices, so that a larger heat transfer takes place in the area of the tool bodies 622, 632 than in the molding devices.
  • Fig. 6 shows a schematic representation of a still further embodiment of a tool component 620 of a mold 610 according to the technical teaching disclosed herein, which shows the concept of the technical teaching disclosed herein to overcome the problems known from the prior art, wherein the distribution of the heating for a tool component 620 is shown.
  • the distribution of the heating also applies to a second tool component 630 with cavities 634 as molding devices.
  • a first heating zone A is provided in the tool body 622 via at least one first heating element 625.
  • a second heating zone B is provided via at least one second heating element 626 per molded part 624.
  • the division into two different heating zones A and B enables individual heating of the molding devices, taking into account the heat energy actually required to evaporate water according to the position on the tool body 622, 632 and the geometry of the product to be manufactured. It is also possible to manufacture different products in a hot pressing process because the heating on the molding surfaces of the molding devices can be individually adjusted.
  • Fig. 7 shows a schematic representation of yet another embodiment of a tool component 620 of a mold 610 according to the technical teaching disclosed herein, wherein the arrangement of a plurality of mold parts 624 is shown. Due to the mutual influence and due to the heat flow via basic heating through at least one first heating element 625 or 635, different heating may be required for each molded part 624 (and also each cavity 634). The requirement of Different heating can also be due to differences in the removal of water vapor generated during the hot pressing process, whereby a sucked-in air flow with water vapor can cool channels and thus the tool body 622. It must also be taken into account how the basic heating of the tool body 622 affects the heating.
  • the mold parts 624 are operated with different maximum power (70-100%), so that the mold parts 624 are heated to different degrees. In the exemplary embodiment, only six mold parts 624 are shown. In mold tools 610 with several molding devices, the required heat energy can differ even further.
  • the required heating power can be determined before a hot pressing process, for example with the help of a calculation program in a simulation.
  • the shape and design of a product to be manufactured is decisive, with products with relatively large mold depths (e.g. > 50 mm) requiring direct heating of the molding devices.
  • heating elements which can be part of heating devices, are arranged in relation to the molding surfaces of the molding devices in such a way that they have a definable distance from the molding surfaces.
  • heating devices and heating elements can also extend around a molding device and/or, for example, run parallel to side walls of the molding devices.
  • indirect heating via the associated tool body is usually provided.
  • the maximum number of molding devices per available area of a tool body 622, 632 must also be determined with regard to the amount of heat that can be provided while achieving the shortest possible hot pressing times. It is not only the maximum area occupied by a tool surface that is important, but also the cooling effect due to the preforms introduced. It is important to note that excessive cooling requires longer hot pressing.
  • a (first) estimate of the required drying energy can be made based on the product geometry, wall thickness and target material of the products to be manufactured.
  • a heating design can then be carried out. This can be done, for example, for a first tool component 622 (lower tool) and a second tool component 632 (upper tool) alone or for both together.
  • Suitable heating devices and heating elements can be selected.
  • electrically controlled heating cartridges can be selected, whereby a selection of heating cartridges (uniform or different types) can also be made, for example depending on the available installation space for placing them (including consideration of wiring, steam and air ducts).
  • a first, rough distribution of the heating cartridges or other heating devices/heating elements can be carried out.
  • the distribution of heating devices/heating elements and their alignment and orientation in the tool can be carried out, for example, in accordance with a heating concept based on the storage mass of the tool material (in particular the tool material for the molding devices).
  • it can be achieved to create distances to the product surface, i.e. to the molding surfaces, that are as equal as possible.
  • a FEM model can be constructed according to the specifications and assumptions and a calculation of the temperature distribution and a possible deformation of the tools (molding devices and/or tool bodies 622, 632) can be carried out according to a calculation model.
  • a dynamic calculation model can be used for this purpose.
  • the results of the calculation of the temperature distribution and/or deformation are analyzed and the selection and distribution of the heating devices/heating elements (e.g. heating cartridges) are optimized. For example, distances can be increased and/or reduced, the alignment and/or orientation of heating devices/heating elements can be changed and/or the heating power can be changed in order to achieve definable temperature distributions on all/selected mold surfaces.
  • a new FEM calculation of the tool can be carried out until the temperature gradients are globally below a definable value.
  • a definable value can, for example, be in a range from 30 °C to 100 °C.
  • the threshold for the temperature gradient is 50 °C.
  • the heating devices/heating elements can be divided into power zones (individual for first tool component 620 and second tool component 630; heating zone A, B).
  • an additional division into zones can be made with regard to the extent over the surface of a tool body 622, 632 (inside - outside and/or molding device-specific for large products).
  • a change in the specific heating powers in the FEM model can be carried out and then a calculation of the temperature distribution and a possible deformation of the tools (forming devices and/or tool bodies 622, 632) can take place.
  • an iteration can take place until a temperature gradient of less than 5 to 30 °C, preferably less than 10 °C, has been achieved. If it is not possible to achieve a temperature gradient of less than 10 °C, the heating design can be restarted.
  • the specific heating output can be read out in a further process step and the selection of devices, materials, etc. as well as the arrangement and control can be documented and adopted as default values for the heating control in a hot press, a mold 610 and/or a fiber processing device 1000.
  • a new calculation for a type of heating device and/or heating element can be carried out automatically.
  • the above change can be made for a possible adjustment of the heating cable and/or the alignment/orientation and/or distance between mold surfaces and heating devices/heating elements.
  • temperatures, pressures and product properties of the product to be manufactured or manufactured as well as of preforms introduced into a molding tool 610 and its original material (pulp) can be monitored via sensors and measuring directions and, in the event of a change, the control of the heating devices can be adjusted (automatically).

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)
EP23193793.9A 2022-09-28 2023-08-29 Moule et procédé de régulation de la répartition de température dans un moule pour produits tridimensionnels Pending EP4345209A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102022124938.7A DE102022124938A1 (de) 2022-09-28 2022-09-28 Verfahren zur regelung einer temperaturverteilung in einem formwerkzeug für dreidimensionale formteile und formwerkzeug

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EP4345209A1 true EP4345209A1 (fr) 2024-04-03

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US (1) US20240102250A1 (fr)
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20030008877A (ko) * 2001-07-20 2003-01-29 김대식 펄프몰드제어시스템 및 펄프몰드시스템
DE102019127562A1 (de) 2019-10-14 2021-04-15 Kiefel Gmbh Faserformanlage zur herstellung von formteilen aus umweltverträglich abbaubarem fasermaterial
US20210138696A1 (en) * 2019-11-11 2021-05-13 Zume, Inc. Molded fiber product production line
WO2022072555A1 (fr) * 2020-09-29 2022-04-07 Zume, Inc. Moules poreux pour fabriquer des parties en fibres moulées et leur procédé de fabrication additive

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20030008877A (ko) * 2001-07-20 2003-01-29 김대식 펄프몰드제어시스템 및 펄프몰드시스템
DE102019127562A1 (de) 2019-10-14 2021-04-15 Kiefel Gmbh Faserformanlage zur herstellung von formteilen aus umweltverträglich abbaubarem fasermaterial
US20210138696A1 (en) * 2019-11-11 2021-05-13 Zume, Inc. Molded fiber product production line
WO2022072555A1 (fr) * 2020-09-29 2022-04-07 Zume, Inc. Moules poreux pour fabriquer des parties en fibres moulées et leur procédé de fabrication additive

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US20240102250A1 (en) 2024-03-28

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