Moulded body for a prepress tool for pressing three-dimensional preforms from a fibrous material and prepress station

Abstract

A molded body for a pre-compression tool for pressing three-dimensional preforms made of a fiber-containing material and a pre-compression station with a pre-compression tool with at least one molded body are described, wherein the molded body consists of a deformable material and has a shell which essentially reflects the geometry of a preform to be pressed, wherein the molded body has at least one support structure made of deformable material which is integrally formed with the shell.

Description

Technical field

[0001] A molded body for a pre-pressing tool for pressing three-dimensional preforms made of a fiber-containing material and a pre-pressing station with a pre-pressing tool with at least one molded body are described.

[0002] Fibrous materials are increasingly used to manufacture packaging for food (e.g., trays, capsules, boxes, etc.) and consumer goods (e.g., electronic devices, etc.), as well as beverage containers. Everyday items, such as disposable cutlery and tableware, are also made from fibrous materials. Fibrous materials include both natural and synthetic fibers. Recently, there has been an increase in the use of fibrous materials that contain natural fibers or are made from fibers derived from renewable resources or recycled paper. The natural fibers are mixed with water and, if necessary, other additives, such as starch, in a pulp. Additives can also affect 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 manufacture packaging, etc., and the product properties of the product being manufactured. background

[0003] The production of fiber-containing products from pulp typically involves several steps. A fiber processing unit comprises multiple stations or forming stations for this purpose. In a forming station, for example, fibers can be drawn into a cavity of a suction tool, thereby forming a preform. For this, the pulp is provided in a pulp reservoir, and the suction tool, with at least one suction cavity whose geometry essentially corresponds to the product to be manufactured, is at least partially immersed in the pulp. During immersion, fibers are drawn in through openings in the suction cavity, which are connected to a corresponding suction device, causing them to accumulate on the surface of the suction cavity. The drawn-in fibers, or the resulting preform, can then be transferred via the suction tool into a pre-compression tool, where the preform is pre-compressed.For this purpose, elastic molds can be used, which are inflated for compression and thereby exert pressure on the preforms. During this pre-compression process, the fibers in the preform are compressed and the water content of the preform is reduced. Alternatively, preforms can be provided by scooping, whereby a scooping tool is immersed in the pulp and, as it is raised, fibers are deposited on the molded parts of the scooping tool.

[0004] Afterwards, preforms are pressed into finished molded parts using a hot pressing machine. Preforms are placed in a hot pressing tool, which typically consists of a lower and an upper mold half, both of which are heated. Within the hot pressing tool, the preforms are compressed in a cavity under heat input. The pressure and heat cause residual moisture to be removed, reducing the moisture content of the preforms from approximately 60% by weight before hot pressing to, for example, 5-10% by weight afterward. The steam generated during hot pressing is extracted through openings in the cavities and channels in the hot pressing tool.

[0005] A manufacturing process and a fiber processing facility for this purpose are known, for example, from DE 10 2019 127 562 A1.

[0006] A disadvantage of known pre-pressing devices is that the deformation of the elastic molded parts is insufficient and varies depending on the geometry of the preforms, resulting in pre-pressed preforms with different wall thicknesses and moisture contents. This, in turn, leads to such preforms sticking to the pre-pressing tool or suction tool and / or tearing. Furthermore, preforms with areas of varying moisture content are also susceptible to damage in subsequent hot-pressing processes, as these areas dry at different rates.

[0007] Elastic molded parts also require a support structure to prevent them from collapsing. However, due to the necessary support structure, the elastic material cannot be adequately inflated, preventing uniform pressure from being applied across the entire surface of the preforms. This results in areas of varying compression within the preforms, exhibiting different wall thicknesses and / or moisture content. Consequently, in subsequent processes (e.g., hot pressing), this leads to damage and destruction of the (pre-)forms, as well as increased cycle times (e.g., pressing duration) and higher tool temperatures (e.g., hot pressing tool). Task

[0008] In contrast, the objective is to provide a solution that addresses the aforementioned problems and allows for improved pre-pressing of fiber-containing preforms with a high water content, whereby the mold bodies for pre-pressing tools and the pre-pressing dies are simply designed, and the costs with regard to maintenance, repair, and operation are reduced. Furthermore, an objective is to provide an alternative to the devices known from the prior art for pre-pressing preforms made of a fiber-containing material. Solution

[0009] The aforementioned problem is solved by a molded body for a pre-pressing tool for pressing three-dimensional preforms made of a fiber-containing material, wherein the molded body consists of a deformable material and has a shell which essentially reflects the geometry of a preform to be pressed, wherein the molded body has at least one support structure made of deformable material which is integrally formed with the shell.

[0010] The integral design of the support structure together with the shell enables the provision of inherent stiffness for the molded body without an additional rigid support body, which in the prior art has so far been formed from a metal block, wherein such a metal block additionally has bores to form channels for supplying a medium, which medium serves to "inflate" the molded body so that the pressing effect on the fiber-containing material of a preform can be provided.

[0011] The deformable material can be an elastic, flexible material that is malleable and generally tends to return to its original shape after deformation. Various materials can be used for this purpose, selected according to the substances and fibrous materials to which the material is exposed.

[0012] Depending on the design of the at least one support element made of a deformable material, such a support element can significantly influence the behavior or deformation (deformation behavior), so that a uniform pressure can be applied to a preform across the entire surface of the shell, resulting in a substantially uniform moisture content and a defined wall thickness after pre-pressing. For this purpose, the support structure can, for example, include strut-like connecting strands that are connected to opposing inner surfaces of the shell. When a medium is introduced, the deformation of the shell is influenced because the connecting strands counteract deformation. Since the connecting strands, like the shell, are made of a flexible material, they can also be deformed, particularly stretched, by pressure prevailing inside the shell, such as that caused by the introduced medium.However, the connecting strands counteract deformation of the shell, resulting in less deformation of the shell in the area of ​​the connection points between the connecting strands and the inside of the shell than in areas of the shell that are not connected by connecting strands or whose distance to such connection points is greater. This allows for targeted influence on the deformability of the shell of molded parts through the design and arrangement of support elements that are integrally formed with the shell.

[0013] The integral design of the at least one support structure with the shell allows, for example, the provision of inherent stiffness via multiple connecting strands, preventing the shell from collapsing or being negatively deformed under external pressure, i.e., being forced inwards by "bulging" against the intended shape direction. Several connecting strands can be arranged such that at least one internal connection, via at least one connecting strand of the at least one support structure, always counteracts any external pressure. In total, by appropriately designing a support structure (e.g., tree-like with multiple branches, each of which has further branches or limbs connected to the inside of the shell), a force can be counteracted by the support structure against any external influence.Within the scope of the technical teaching disclosed herein, embodiments are included in which the shell can be locally depressed to a small extent by external pressure, but immediately returns to its original shape on its own after the pressure is applied. This is achieved in particular by the deformable material of the support structure (and the shell), which is elastic.

[0014] Such a shaped body can be manufactured, for example, using an additive manufacturing process. 3D printing allows for the production of very delicate support structures that are integrally connected to the inner surface of the shell, thus ensuring optimized shell expansion. Additive manufacturing, in particular, enables seamless adaptation to the required wall thicknesses, diameters, and directions of action without compromise. In summary, this allows for the production of a shaped body with a support structure that is precisely tailored to the requirements (e.g., shape behavior).

[0015] Furthermore, such a shaped body already has a receiving space for a medium that provides a deformation.

[0016] In further embodiments, connecting strands can have several thinner, thread-like connecting threads at their end compared to a middle section, which extend over a relatively large area and are thus connected to the inside of the shell over a larger area, so that the expansion of the deformable material can be additionally influenced and controlled.

[0017] In further embodiments, the deformable material of the at least one support structure and the deformable material of the shell can differ with regard to their elasticity, whereby the deformation behavior of the molded body, in particular the shell, can be further influenced.

[0018] In further embodiments, the casing can have at least one raised section on an outer surface used for compression. This raised section facilitates the compression of fibrous material, particularly at transitions, such as the transition between the base of a fibrous preform and a side wall, preventing material accumulation in the transition area after compression. Furthermore, it allows for the creation of depressions in a fibrous material during compression.

[0019] In further embodiments, the shell can have a greater wall thickness in the area of ​​at least one raised section compared to areas of the shell without at least one raised section on the outer surface. This allows for targeted compression in these reinforced areas, resulting from the raised section's formation and not solely from the expansion of the shell's deformable material. The raised section can be pressed into a groove or depression (e.g., a transition) on its outer surface, with the inner surface of the shell deforming to the same extent as adjacent areas without a raised section. However, the raised section also allows for the targeted displacement of an outer surface of the shell into a depression, for which the shell's wall thickness in the raised section is increased by the height of the raised section. This is, for example,This is also advantageous in transitions as described above, because it prevents excessive material displacement and / or compression at excessive pressure, which could ultimately result in an area that is too thin.

[0020] In further versions, the shell can be deformable to varying degrees depending on its wall thickness. This allows, on the one hand, targeted areas of the preform to be pressed more or less firmly, and on the other hand, a constant pressing force to be set across the entire surface or a definable area of ​​the preform if the shell is deformed during pre-pressing.

[0021] In further embodiments, the at least one support structure can have an open-pore structure and / or at least one cavity, at least in sections. An open-pore structure and a cavity can weaken sections of the at least one support structure, so that, for example, these sections are more easily deformable or more elastic compared to sections without an open-pore structure or cavity, even with the same diameter or cross-section. Cavities can have various shapes, such as elongated, teardrop-shaped, or spherical.

[0022] In further embodiments, the shell can be perforated, at least in sections. This perforation allows the medium introduced for deformation (e.g., gas or gas mixture, such as compressed or ambient air), which primarily presses a preform against a corresponding cavity wall during pre-pressing in a pre-pressing tool, to additionally penetrate a moist preform and thus aid dewatering during the pressing process. Furthermore, this prevents excessive pressure, allowing the elastic mold to be deformed more uniformly. As a result, preforms can be dewatered more effectively because the airflow through the preform carries away additional moisture as it becomes saturated.

[0023] In further embodiments, the at least one support structure can have at least one strut which is connected to the shell at at least one first end. Such a strut can, for example, be designed as a connecting strand, as described above.

[0024] In further embodiments, the at least one support structure can have at least one second end that can be connected to a pre-pressing tool. For example, the at least one support structure can be connected to a tool holder for a molded body of a tool plate, the tool plate providing a counter bearing during deformation.

[0025] In further embodiments, the at least one supporting structure can have several struts, whereby the elasticity and deformation behavior of the shell can be determined according to the position of the ends. The struts can be designed as described above, and can also include connecting strands that form a tree-like structure with several branches and twigs.

[0026] In further embodiments, the molded body can have a connection area for a pre-pressing tool, in which an integrated connecting unit is arranged. Via a connection area and a connecting unit, molded bodies can be detachably connected to a tool holder of a pre-pressing tool, or connected to a tool holder, so that replacement for maintenance purposes, during a product change, etc., is possible.

[0027] The connection area is the point where the mold body is connected to a pre-compression tool and can be connected to a tool component via the connection unit. The connection unit allows the mold body to be connected, or connectable, to a tool component of a pre-compression tool, such as a tool plate. An integrated design includes, for example, versions in which the connection unit is completely or almost completely surrounded by the flexible material of the mold body. High loads occur in the connection area during closing to compress preforms, so the reinforced design provides sufficient rigidity to counteract damage. This also allows for pre-compression of preforms in an edge area. This is achieved through the increased wall thickness and overall stronger design, which includes at least one metal insert (e.g., a metal plate).The connecting unit can be further reinforced, providing a sufficiently stable pressing surface or counter-pressing surface against another tool. The interchangeability of a molded part via the connecting unit enables tool changes and maintenance without, for example, having to replace or service an entire tool plate with multiple molded parts.

[0028] In further embodiments, the at least one support structure can have an integrated connection unit for connection with a pre-pressing tool.

[0029] In further embodiments, the shell and the at least one support structure can be connected by a common connecting unit or have a common connecting unit.

[0030] In further embodiments, the shell can be closed in a connection area, which has at least one port for introducing a medium. Such molded bodies with integrated support structures can be manufactured particularly well using additive manufacturing processes, since even internal structures can be produced in essentially closed molded bodies.

[0031] Furthermore, the connecting unit can be made of or comprise a metal or a metal alloy. In further embodiments, the connecting unit can have at least one connecting element, wherein the at least one connecting element can be or comprise a groove, a threaded bore, a pin, a screw, or a snap-in opening. In further embodiments, the connecting area of ​​the molded body for a pre-compression tool can extend into an edge region of a preform. In further embodiments, the molded body can have a substantially uniform wall thickness in the wall and bottom regions of three-dimensional preforms. In further embodiments, the molded body can be made of or comprise silicone or thermoplastic elastomers, in particular thermoplastic polyurethanes (TPU).The aforementioned materials have proven advantageous for pre-pressing because they can be used in a wide temperature range and, depending on the mixture and design, are sufficiently flexible while also withstanding sufficient pressure for pre-pressing.

[0032] In further embodiments, the shell and / or the supporting structure can incorporate reinforcement. Reinforcement can, for example, serve to push the shell at least radially outwards. Such reinforcement can be formed by the deformable, elastic material of the shell or the supporting structure, whereby the elastic material of the reinforcement is less deformable than, for example, the shell itself. This ensures that an outward force is always exerted on the shell via the reinforcement, thus maintaining its shape. For example, the reinforcement can be helical and located on the inner wall of the shell. In further embodiments, the reinforcement can also be formed by a wire or similar element integrated into the shell, so that the shell itself maintains its position and shape. Due to its integration into the shell, the wire is also protected from external influences and is not affected by moisture or gases.In further variations, reinforcement can be achieved by fibers embedded in the elastic material. Such fibers can be, for example, aramid, glass, or carbon fibers. This allows the mechanical properties (e.g., modulus of elasticity) of the deformable, elastic material to be modified, for example, to make the material more resistant or less deformable, or to prevent or counteract damage to the material.

[0033] The aforementioned problem is also solved by a pre-compression station with a pre-compression tool comprising at least one first tool component with at least one tool holder for a molded body and at least one molded body for pressing three-dimensional preforms made of a fiber-containing material according to one of the embodiments described above, and with at least one second tool component comprising at least one cavity for receiving preforms, wherein a molding space for pressing preforms in the closed state of the pre-compression station is formed between an outer surface of a shell of the molded body and an inner wall of the cavity, and wherein the at least one molded body is connected to the tool holder via at least one support structure integrally formed with the shell and a connection area of ​​the shell.

[0034] By forming the molded body with an integral support structure made of a deformable material, in particular an elastic material, it is possible to dispense with support bodies for the molded body and, on the other hand, to achieve an adjustable offset, i.e., distance between the surface of the shell and the inner wall of the cavity (mold surface), during pressing when the molded body is deformed or the shell is pressed against a fiber-containing material in the cavity via a medium.

[0035] In further embodiments, the outer surface of the shell can have a shape essentially adapted to the surface contour of the inner wall of the cavity.

[0036] In further embodiments, the outer surface of the shell can have at least one elevation that corresponds to a transition and / or a depression on the inner wall of the cavity, so that a substantially uniform compression of the fibrous material of a preform can be achieved even in such sections of the cavity, so that the preform has a uniform wall thickness and / or moisture content after compression.

[0037] In further embodiments, the molded body can have an integrated connection unit in the connection area and / or in the at least one support structure for a connection with the tool holder.

[0038] In further embodiments, the first tool component can have at least one channel through which a gas or gas mixture can be introduced into the shell of the molded body in order to deform the shell and press a preform introduced into the molding space against the inner wall of the cavity via the outer surface of the shell.

[0039] In further embodiments, the wall thickness of the deformable material of the shell and the arrangement of the at least one support structure can be designed according to the geometry of a preform to be pressed, so that during pre-pressing, an essentially uniform pressure on the preform can be generated between the outer surface of the shell of the molded body and the inner wall of the cavity in the closed state of the pre-pressing station.

[0040] In further embodiments, in an undeformed state of the molded body, in particular the shell, the distance between the surface of the shell and the inner wall of the cavity can be of different sizes, whereby a substantially uniform pressure over the entire surface of a preform is also achieved by the shell through the formation and connection of the support structure to the shell.

[0041] Furthermore, at least one cavity may have openings for draining water that escapes from preforms during a pre-pressing process.

[0042] Further features, designs and advantages will become apparent from the following presentation of exemplary embodiments with reference to the figures. Brief description of the characters

[0043] The drawings show: Fig. 1 a schematic representation of a fiber forming plant for the production of products from a fiber material; Fig. 2 a schematic representation of an embodiment of a molded body and tool parts in a pre-pressing station before a pre-pressing step; Fig. 3 a schematic representation of another embodiment of a molded body and tool parts in a pre-pressing station before a pre-pressing step; Fig. 4 a schematic representation of yet another embodiment of a molded body and tool parts in a pre-pressing station before a pre-pressing step; Fig. 5 a schematic representation of the embodiment of Fig. 4during a pre-pressing step; Fig. 6 shows schematic representations of embodiments of a shell with integrated reinforcement; Fig. 7 a further schematic representation of an embodiment of a molded body with a support structure; and Fig. 8 a yet another schematic representation of an embodiment of a molded body with a support structure. Detailed description of implementation examples

[0044] The following are exemplary embodiments of the technical teaching described herein, with reference to the figures. The same reference numerals are used in the figure descriptions for identical components, parts, and processes. Components, parts, and processes that are immaterial to the technical teaching disclosed herein or that are obvious to a person skilled in the art are not explicitly shown. Features given in the singular are also included in the plural unless explicitly stated otherwise. This applies in particular to terms such as "a" or "an".

[0045] Fig. 1 Figure 1 shows a schematic representation of a fiber processing unit 1000 for the production of three-dimensional molded parts from a fiber-containing material. In the illustrated embodiment, the fiber-containing material for the production of molded parts is prepared in a pulp tank 250 of the fiber processing unit 1000. For this purpose, water and fibers, as well as any additives, can be introduced into a pulp tank 250 via a liquid supply, and the pulp is prepared in the pulp tank 250 by mixing the individual components with the input of heat and auxiliary equipment, such as a stirrer.

[0046] Pulp is defined as an aqueous solution containing fibers, with the fiber content ranging from 0.1 to 10 wt%. It may also contain additives such as starch, chemical additives, wax, etc. The fibers can be, for example, natural fibers like cellulose fibers or fibers derived from a fibrous source material (e.g., recycled paper). A fiber processing plant offers the capability to process pulp in large quantities and supply it to multiple fiber processing units.

[0047] The Fiber Processing Unit 1000 can be used to produce, for example, biodegradable cups 3000, capsules, bowls, plates, and other molded and / or packaging parts (e.g., as holders / support structures for electronic devices). Since the starting material for these products is a fiber-containing pulp with natural fibers, the products manufactured in this way can themselves serve as a starting material for the production of such products after use, or can be composted, because they are generally completely decomposable and do not contain any harmful or environmentally hazardous substances.

[0048] The in Fig. 1The fiber processing unit 1000 shown has a frame 150, which may be enclosed by a casing. The supply units 300 of the fiber processing unit 1000 include, 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 intake unit 320, piping 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 may also exist instead of a wired data connection. The data connection may, for example, exist between the control unit 310 and a central control system for several fiber processing units 1000, a fiber processing plant, a service center, and / or other facilities.The fiber processing unit 1000 can also be controlled via a bidirectional data connection using a mobile device, such as a smartphone, tablet computer or the like.

[0049] The control unit 310 communicates bidirectionally with an HMI panel 700 via a bus system or data connection. The HMI (Human-Machine Interface) panel 700 features a display that shows operating data and statuses of the fiber processing unit 1000 for selectable components or the entire fiber processing unit 1000. The display can be a touchscreen, allowing an operator of the fiber processing unit 1000 to manually adjust settings. Additionally or alternatively, the HMI panel 700 can be equipped with other input devices, such as a keyboard, joystick, or keypad, for operator input. These allow settings to be changed and the operation of the fiber processing unit 1000 to be influenced.

[0050] The fiber processing unit 1000 includes a robot 500. The robot 500 is designed as a so-called 6-axis robot and is therefore capable of picking up parts, rotating them, and moving them in all spatial directions within its operating radius. Instead of the robot 500 shown in the figures, other handling devices can also be provided, designed to pick up and twist or rotate products and move them in various spatial directions. Furthermore, such a handling device can also be configured differently, in which case the arrangement of the corresponding stations of the fiber processing unit 1000 may differ from the illustrated embodiment.

[0051] A suction tool 520 is arranged on the robot 500. In the illustrated embodiment, the suction tool 520 has cavities, formed as negatives of the three-dimensional molded parts to be formed, such as cups 3000, as suction cavities 522. The suction cavities 522 can, for example, have a mesh-like surface to which fibers from the pulp adhere during suction. Behind the mesh-like surfaces, the cavities are connected to a suction device via channels in the suction tool 520. The suction device can be implemented, for example, by a suction device 320 or a fan. Pulp can be drawn in via the suction device when the suction tool 520 is positioned within the pulp basin 250 such that the suction cavities 522 are at least partially immersed in the aqueous fiber solution, i.e., the pulp. A vacuum or...A vacuum for drawing in fibers, when the suction tool 520 is located in the pulp basin 250 and the pulp, can be provided via the suction device 320. For this purpose, the fiber processing unit 1000 has corresponding means at the supply units 300. The suction tool 520 has lines for providing the vacuum / negative pressure from the suction device 320 at the supply units 300 to the suction tool 520 and the openings in the suction cavities 522. Valves are arranged in the lines, which can be controlled via the control unit 310 and thus regulate the suction of the fibers. Instead of suction, the suction device 320 can also be used for "blowing out," for which the suction device 320 is switched to a different operating mode according to its design.

[0052] In the production of molded parts from a fiber material, the suction tool 520 is immersed in the pulp and a negative pressure / vacuum is applied to the openings of the suction cavities 522, so that fibers are sucked out of the pulp and, for example, adhere to the network of the suction cavities 522 of the suction tool 520.

[0053] The robot 500 then lifts the suction tool 520 from the pulp basin 250 and moves it, along with the fibers adhering to the suction cavities 522, which still have a relatively high moisture content of, for example, over 80 wt% water, to the pre-compression station 400 of the fiber processing unit 1000, maintaining negative pressure in the suction cavities 522 for the transfer. The pre-compression station 400 has a pre-compression tool with pre-compression molds 410. The pre-compression molds 410 can, for example, be designed as positive models of the molded parts to be produced and have a corresponding size, relative to the shape of the molded parts, to accommodate the fibers adhering to the suction cavities 522.

[0054] In the production of molded parts, the suction tool 520, with the fibers adhering to the suction cavities 522, is moved to the pre-compression station 400 in such a way that the fibers are pressed into or against the suction cavities 522. This compresses the fibers together in the suction cavities 522, creating a stronger bond between them. Furthermore, the moisture content of the preforms formed from the suction fibers is reduced, so that the preforms produced after pre-compression have a moisture content of, for example, only 60 wt.%. Flexible pre-compression molds 410 can be used to expel water. These molds are inflated, for example, with compressed air (process air), pressing the fibers against the wall of a suction cavity 522 of another suction tool component. This inflation process expels water and reduces the thickness of the suctioned fiber layer.

[0055] During pre-pressing, liquid or pulp can be extracted and returned via the suction tool 520 and / or via further openings in pre-pressing molds 410 or tool parts (cavities).

[0056] After pre-pressing in the pre-pressing station 400, the preforms produced are moved by the robot 500 to a hot pressing station 600 using the suction tool 520. For this purpose, the vacuum is maintained at the suction tool 520 so that the preforms remain in the suction cavities 522. The preforms are transferred via the suction tool 520 to a lower tool body 620, which can be moved along the production line from the hot pressing unit 610. When the lower tool body 620 is in its extended position, the suction tool 520 is moved towards the lower tool body 620 so that the preforms can be placed onto the forming devices of the lower tool body 620.Subsequently, overpressure is generated via the openings in the suction tool 520, so that the preforms are actively deposited from the suction cavities 522, or the suction is terminated, so that the preforms remain on the forming elements of the lower tool body 620 due to gravity. By providing overpressure at the openings of the suction cavities 522, pre-pressed preforms that are in contact with / adhere in the suction cavities 522 can be released and discharged.

[0057] Afterwards, the suction tool 520 is moved away via the robot 500 and the suction tool 520 is immersed in the pulp basin 250 to suck up further fibers for the production of molded parts from fiber-containing material.

[0058] After the preforms are transferred to the hot pressing station 600, the lower tool body 620 moves. In the hot pressing station 600, the preforms are pressed into finished parts under heat and high pressure. For this purpose, an upper tool body 630 is brought onto the lower tool body 620 by a press. The upper tool body 630 has cavities corresponding to the forming units. After the hot pressing process, the lower tool body 620 and the upper tool body 630 are moved away from each other, and the upper tool body 630 is moved along the fiber processing unit 1000 in the production direction. After hot pressing, the finished parts are drawn over the upper tool body 630 and thus remain within the cavities.The manufactured molded parts are thus removed from the hot pressing station 600 and, via the upper tool body 630, placed onto a conveyor belt of a conveying device 800. After placement, the suction via the upper tool body 630 is terminated, and the molded parts remain on the conveyor belt. The upper tool body 630 returns to the hot pressing station 600, and another hot pressing operation can be carried out. Alternatively, the lower tool body 620 can be moved in the opposite direction before extending to receive the preforms, in order to remove the manufactured products / molded parts from the hot pressing device for further transport.

[0059] The fiber processing unit 1000 also includes a conveyor unit 800 with a transport belt. After final forming and hot pressing in the hot pressing station 600, the manufactured molded parts made of fiber-containing material can be placed on the transport belt and discharged from the fiber processing unit 1000. In further configurations, additional processing can take place after the molded parts are placed on the conveyor belt of the conveyor unit 800, such as filling and / or stacking the products. Stacking can be carried out, for example, by an additional robot or other equipment.

[0060] The fiber processing unit 1000 made of Fig. 1Figure 1 shows a possible embodiment. A fiber processing device according to the technical teaching described herein can also comprise only one forming station with an interchangeable tool, e.g., a suction tool 520 or a hot press tool, in which fiber-containing material can be processed, wherein various tools for producing different three-dimensional molded parts can be accommodated in the at least one forming station. The further details for the fiber processing device 1000 are described below. Fig. 1 The stations and devices shown are not absolutely necessary for the implementation of the technical teaching.

[0061] Fig. 2 Figure 1 shows a schematic representation of an embodiment of a molded body 420 made of an elastic material 422, a pre-pressing mold 410, a pre-pressing tool, and a pre-pressing station 400 in a sectional view. Fig. 2In addition, a tool body 402 of the pre-pressing tool of a pre-pressing station 400 and a tool body 526 of the suction tool 520 are shown schematically.

[0062] The elastic material 422 is perforated and has a large number of small openings, as shown in Fig. 2 schematically indicated by the openings 428. The diameter of the perforation or the openings 428 is preferably in the range of 0.4 to 1.5 mm.

[0063] The deformable, elastic material of the molded body 420 is in the exemplary embodiment of Fig. 2 directly connected to the tool body 402, although this is only one of a variety of connection options. For example, a detachable connection can be made via connecting units 432, as shown below with reference to the Figs. 3 to 5 revealed.

[0064] In contrast to prior art designs, the molded body 420 does not require a support structure made of a metal block or the like. To prevent the molded body 420 from collapsing, it has an internal support structure 440, which is integrally formed with a shell 480 and is made of an elastic material. The shell 480 and the support structure 440 can be made of the same material and can be produced, for example, using an additive manufacturing process (e.g., 3D printing) to ensure the integral formation of the shell 480 and the support structure 440. Suitable elastic materials include, for example, silicones or thermoplastic elastomers, in particular thermoplastic polyurethanes (TPU).

[0065] The support structure 440 has several struts 460 which are connected or integrally formed with the inside of the shell 480 via a first end in a connection area 462. In the illustrated embodiment, second ends are connected to the tool body 402 in connection areas 464.

[0066] Fig. 2Figure 1 shows a schematic representation of the design of struts 460. In further embodiments, multiple struts 460 may be provided. In further embodiments, the struts 460, particularly in the connection areas 462, may be designed such that a connection exists over a relatively large area. The connection area of ​​the struts 460 in the connection area 462 may be larger than, for example, the diameter of the struts 460. For this purpose, the struts 460 may be fanned out at their ends and, for example, have a multitude of branches that extend over a surface and are connected to the inside of the shell 480. In further embodiments, a support structure 440 may be designed in a tree-like manner, with several struts 460 projecting from a central section, which divide into further struts 460 in a branch-like manner, which themselves may, in further embodiments, have struts 460 designed as twigs.The struts 460 can have a decreasing diameter depending on the type (branch, twig, etc.), while the number of struts 460 can increase.

[0067] The connection of the ends in the connection areas 462 can be carried out according to the shape of the shell 480, the shell 480 itself essentially having the geometry of a molded part to be produced or of the preform to be pressed. In the connection areas 462, the material of the shell 480 is more strongly retained than in areas of the shell 480 that are not connected to a strut 460. Therefore, an optimal distribution and dimensioning of the connection areas 462 is crucial for determining the deformability of the shell 480, in addition to the material of the shell 480 and the struts 460. Furthermore, a targeted arrangement and connection of struts 460 can counteract the collapse of the shell 460, provided that the struts 460 mutually ensure that the shell 480 retains its basic structure.Although external pressure on the shell 480 can slightly deform it and push it inwards, the shell 480 automatically returns to its original position after the pressure is removed due to the flexible material of the shell 480 and the support structure 440 and their design.

[0068] The support structure 440 and struts 460 thereof can in all versions have sections that are open-pored and / or have cavities in order to influence the mechanical properties of the support structure 440 and / or struts 460 and / or to save weight and material.

[0069] The tool body 402 includes a supply channel 404 through which compressed air can be introduced. The introduced compressed air flows into an interior space 490 and causes the flexible material 422 of the shell 480 of the mold body 420 to deform or "inflate." Depending on the thickness and material used for the flexible material 422, the pressure and volume flow rate of the introduced compressed air, and other factors such as the perforation of the flexible material 422, the deformability of the shell 480 can be influenced and controlled. Furthermore, the number and design of the struts 440 and their connection to the inside of the shell 480 determine the deformability.

[0070] In the illustrated embodiment, the shell 480 has areas with substantially the same wall thickness and areas with protrusions 470. The protrusions 470 are located in areas opposite transitions on the molded surface of the intake cavity 522, as shown in Fig. 2As shown schematically, when a gas or gas mixture is introduced via the feed channel 402 into the interior 490 of the mold body 420 of the pre-press mold 410, the flexible, deformable material expands, causing the shell 480 to press against the fiber-containing material 900 previously introduced into the intake cavity 522. The protrusions 470 are pressed into the transitions and compensate for weaknesses that arise due to the deformability of the elastic material. These weaknesses arise particularly because, although the elastic material is essentially homogeneously deformable, it cannot fully penetrate or be pressed into transitions (e.g., corners, grooves, etc.) because this would require increasing the pressure, which would lead to excessive compression of the fiber-containing material 900 in the adjacent areas. This can be achieved, for example, by varying the wall thickness of the shell 480.By forming protrusions 470, which extend outwards from the shell 480, uniform compression of the fibrous material 900 can be achieved particularly easily over the entire length of preforms, even in such transitions, with uniform deformation of the shell 480. The pressure exerted on the fibrous material 900 by the shell 480 is essentially the same. This ensures that the fibrous material 900 of a preform is compressed uniformly, so that the fibrous material 910 of the preform has a substantially uniform moisture content after pre-compression. The perforation of the flexible material 422 also allows air to be drawn through the fibrous material of a preform for dehumidification.The design of the perforation and the applied compressed air must be coordinated so that the deformation of the flexible material 422 takes place to a sufficient degree to provide the required pressing pressure necessary for squeezing water out of the relatively moist preforms.

[0071] The previously specified wall thickness of the shell 480 extends essentially over the area (product area) of the molded body 420, which is in contact with the preform to be pressed during pre-pressing.

[0072] Fig. 3 Figure 1 shows a schematic representation of a further embodiment of a molded body 420 and tool parts in a pre-pressing station 400 before a pre-pressing step, wherein a connecting unit 432 is provided, which is essentially plate-like. The connecting unit 432 of Fig. 3A common connecting unit 432 for the shell 480 and the support structure 440 is directly connected to the plate or connecting unit 432, which is made of a metal or a metal alloy. For example, the shell 480 and the support structure 440 can be integrally integrated into recesses in the plate. This can be implemented, for example, in an additive manufacturing process, whereby material is introduced into the recesses of the plate to form the shaped body 420.

[0073] The connecting unit 432 also has an opening 434 which, in the connected state of the pre-pressing mold 410 and the tool body 402, is congruent with the feed channel 404, so that a medium (gas, gas mixture) can be introduced into the interior 490 to deform the shell 480.

[0074] The connecting unit 432 can additionally have connecting elements, such as threaded bores, etc., so that the connecting unit 432 and thus the entire pre-pressing mold 410 can be reversibly connected to the tool body 402.

[0075] Fig. 4Figure 1 shows a schematic representation of a further embodiment of a mold body 420 and tool components in a pre-pressing station 400 prior to a pre-pressing step, wherein the connecting unit 432 is ring-shaped and integrated into a connecting section 430. The connecting section 430 is formed integrally with the shell 480 and the support structure 440 and has an opening 434 for introducing a medium into the interior 490. In this embodiment, the connecting unit 432 is made of a metal or a metal alloy and may, for example, have threaded bores, etc., to reversibly connect the pre-pressing mold 410 to a tool body 402. For example, screws can engage in the threaded bores from the tool body 402, thus essentially without affecting the interior 490.

[0076] In further embodiments, the connecting units 432 shown in the figures can also be reversibly connected to a tool body 402 via clamping, locking or snap connections.

[0077] Fig. 5 shows a schematic representation of the embodiment of Fig. 4 during a pre-pressing step. As in Fig. 5 As shown, the formation of the molded body 420 causes a deformation of the elastic material 422 when a medium (schematically indicated by the arrows) is introduced into the interior 490, resulting in a substantially uniform distance between the molded surface of the intake cavity 522 and the outer surface of the shell 480. Furthermore, a sharp demarcation can be achieved at the transitions, as shown schematically in particular at the transition between the bottom and wall of the preform or fibrous material 910, as well as in the central elevation and at the transition from the wall to an edge.

[0078] Firstly, the elevations 470 press specifically into the transitions, and secondly, the support structure 440 significantly influences the deformation of the shell 480, as the struts 460 counteract deformation.

[0079] During pre-pressing, the suction tool 520 with the suction cavities 522 is moved towards the pre-pressing tool. Fibers from the pulp are deposited on nets or other similarly designed surfaces in the suction cavities 522. Fig. 2 Figure 5 shows part of an intake cavity 522 with channels 524 for drawing fibers from a pulp and for holding the fibers in the drawn-in filter cakes or preforms. Water is also drawn from the filter cake and preforms via the channels 524. Particularly during pre-pressing, the pressed-out water is discharged through these channels. The mesh, which is located on the surface of the intake cavities 522, is in Fig. 2 not shown in detail.

[0080] Once the tool body 526 has come into contact with the tool body 402, the pre-pressing process can be started, for which, for example, compressed air is introduced into the interior 490 of the mold body 420 for deformation. This results in uniform deformation of the flexible material 422 and thus uniform pre-pressing.

[0081] After the molded body 420 is positioned in the intake cavity 522 with pre-aspirated fiber-containing material 900, the pre-compression process starts and the fiber-containing material 900, or the preform, is compressed and dewatered, thereby reducing the wall thickness of the preform. The preforms are located within the cavity 522. Fig. 2 , 3 , 4 The shown mold space is located between the outer surface of the molded body 420 and the inner surface of the intake cavity 522, or the mesh or mesh-like structure arranged therein. This is particularly evident from a comparison of the Fig. 4 and5 It is evident that the mold space is reduced when the molded body 420 is deformed, so that pressure can build up on the fiber-containing material 900 introduced therein. Such pressure then causes the material to be compressed, whereby water is squeezed out and carried away via the channels 524.

[0082] The figures only partially show a pre-compression mold 410 and an intake cavity 522. In further embodiments, a pre-compression tool and an intake tool 520 can be designed as multi-cavity tools and thus have several intake cavities 522 and corresponding pre-compression molds 410.

[0083] Fig. 6 shows schematic representations of designs of a shell 480 with integrated reinforcement 450. Fig. 6aFigure 480 shows a sectional view of part of a sheath 480 into which a wire or the like is incorporated as reinforcement 450 within the elastic material 422. The wire can, for example, be incorporated in a helical fashion within the sheath 480, as shown in Figure 422. Fig. 6b It has been shown that the casing 480 constantly strives to maintain its shape. However, the wire still allows deformation for the purpose of compressing fibrous material 900.

[0084] Fig. 7 Figure 1 shows a further schematic representation of an embodiment of a molded body 420 with a support structure 440, wherein at least part of the struts 460 have a curved profile, so that they exert a radially outward force which holds the shell 480 in shape and counteracts inward deformation. These struts 460 act as springs against deformation. However, deformation for compression can occur and is supported by the design of the spring-like struts 460.

[0085] Fig. 8 Figure 1 shows a further schematic representation of an embodiment of a shaped body 420 with a support structure 440, wherein the struts 460 are tree-like and several struts 460 extend as branches from a main strut, which themselves may be divided into twigs.

[0086] In all embodiments shown in the figures, the elastic material of the casing 480 can be perforated and have openings 428, as for example in Fig. 2 shown schematically.

[0087] The formation of molded bodies 420 described herein enables the pre-pressing of fibrous material 900, which rests on a surface (e.g., mesh) of an intake cavity 522 of an intake tool 520 and, as schematically shown in the figures, can exhibit frequently varying layer thicknesses. This pre-pressing process ensures that the fibrous material 910, or the resulting preforms, has a defined wall thickness across the entire geometry of the preform and that the moisture content is significantly reduced. The method described herein allows for optimization of the pre-pressing effect, as this is highly dependent on the product geometry and the material. This includes product-specific, local adjustments to stiffness, geometry, porosity, and offset (distance between the tools before inflation). Consequently, significantly higher (>40%, up to 50%) and more uniform dry contents across the product surface can be achieved compared to known pre-pressing stations.Furthermore, the pre-pressing time can be reduced, as the entire surface is subjected to the same high efficiency (pressure, airflow). Reference symbol list

[0088] 150 Frame 250 Pulp basin 300 Supply units 310 Control unit 320 Suction unit 400 Pre-compression station 402 Tool body 404 Feed channel 410 Pre-compression mold 420 Mold body 422 Material 428 Opening 430 Connection section 432 Connection unit 434 Opening 440 Support structure 450 Reinforcement 460 Strut 462 Connection area 464 Connection area 470 Elevation 480 Shell 490 Interior 500 Robot 520 Suction tool 522 Suction cavity 524 Channel 526 Tool body 600 Hot pressing station 610 Hot pressing unit 700 HMI panel 800 Conveyor 810 Camera 900 Fibrous material 910 Compressed fibrous material 1000 Fiber processing equipment 3000 cups

Claims

1. Mold body for a pre-pressing tool for pressing three-dimensional preforms made of a fibrous material, wherein the mold body consists of a deformable material and has a shell which essentially reflects the geometry of a preform to be pressed, wherein the mold body has at least one support structure made of deformable material which is integrally formed with the shell.

2. Molded body according to claim 1, wherein the deformable material of the at least one support structure and the deformable material of the shell differ with respect to their elasticity.

3. Molded body according to claim 1 or 2, wherein the shell has at least one protrusion on an outer surface used for compression.

4. Molded body according to claim 3, wherein the shell has a greater wall thickness in the area of ​​the at least one protrusion compared to areas of the shell without at least one protrusion on the outer surface.

5. Molded body according to one of claims 1 to 4, wherein the at least one support structure has at least partially an open-pore structure and / or at least one cavity.

6. Molded body according to one of claims 1 to 5, wherein the shell is formed with perforations at least in sections.

7. Molded body according to one of claims 1 to 6, wherein the at least one support structure has at least one strut which is connected to the shell at at least one first end.

8. Molded body according to claim 7, wherein the at least one support structure has at least one second end which can be connected to a pre-pressing tool.

9. Molded body according to claim 7 or 8, wherein the at least one support structure has several struts, wherein the elasticity and deformation behavior of the shell can be determined according to the position of the ends.

10. Molded body according to any one of claims 1 to 9, wherein the molded body has a connection area for a pre-pressing tool in which an integrated connection unit is arranged.

11. Molded body according to one of claims 1 to 10, wherein the at least one support structure has an integrated connection unit for connection with a pre-pressing tool.

12. Molded body according to any one of claims 1 to 11, wherein the shell and the at least one support structure are connected by a common connecting unit or have a common connecting unit.

13. Molded body according to one of claims 1 to 12, wherein the shell is closed in a connection area, the connection area having at least one connection for introducing a medium.

14. Molded body according to any one of claims 1 to 13, wherein the shell and / or the support structure has a reinforcement which pushes the shell at least radially outwards.

15. Pre-compression station with a pre-compression tool comprising at least one first tool component with at least one tool holder for a molded body and at least one molded body according to one of claims 1 to 14 for pressing three-dimensional preforms made of a fiber-containing material, and with at least one second tool component comprising at least one cavity for receiving preforms, wherein a molding space for pressing preforms in the closed state of the pre-compression station is formed between an outer surface of a shell of the molded body and an inner wall of the cavity, and wherein the at least one molded body is connected to the tool holder via at least one support structure integrally formed with the shell and a connection area of ​​the shell.

16. Pre-pressing station according to claim 15, wherein the outer surface of the shell has at least one protrusion which is associated with a transition and / or depression on the inner wall of the cavity.

17. Pre-pressing station according to claim 15 or 16, wherein the molded body has an integrated connection unit in the connection area and / or in the at least one support structure for a connection with the tool holder.

18. Pre-compression station according to one of claims 15 to 17, wherein the first tool component has at least one channel through which a gas or gas mixture can be introduced into the shell of the molded body in order to deform the shell and to press a preform introduced into the molding space over the outer surface of the shell against the inner wall of the cavity.

19. Pre-compression station according to one of claims 15 to 18, wherein the wall thickness of the deformable material of the shell and the arrangement of the at least one support structure are designed according to the geometry of a preform to be compressed, so that during pre-compression a substantially uniform pressure on the preform can be generated between the outer surface of the shell of the molded body and the inner wall of the cavity in the closed state of the pre-compression station.

20. Pre-pressing station according to one of claims 15 to 19, wherein in an undeformed state the distance between the surface of the shell and the inner wall of the cavity is of different sizes.

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