TOOL FOR PROCESSING FIBER-CONTAINING MATERIAL, MOLDING PLANT AND METHOD FOR MANUFACTURING FIBER-CONTAINING PRODUCTS

Description

PRIORITY CLAIM

The present application claims priority under 35 U.S.C. § 119 to German Patent Application No. DE 10 2024 107 894.4, filed Mar. 20, 2024, the disclosure of which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

A tool for processing fiber-containing material for the manufacture of three- dimensional products, a molding plant for manufacturing fiber-containing products and a method for the manufacture of fiber-containing products are described.

BACKGROUND

Fiber-containing materials are sometimes used, for example, to produce 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 fiber-containing material. Fiber-containing materials contain natural fibers or artificial fibers. Recently, fiber-containing material is increasingly used that has or is made of natural fibers that can be obtained, for example, from renewable raw materials or waste paper.

Fiber-containing materials can be processed in a moist state in a so-called “wet fiber” molding process, whereby natural fibers are mixed, for example, in an aqueous fiber suspension (pulp) and possibly other additives such as starch. This pulp can for example have a proportion of natural fibers of, for example, 0.5 to 10 wt. %. The proportion of natural fibers varies depending on the method used for the production of packaging etc. and the product properties of the product to be produced. Additives in a pulp can also have effects on color, barrier properties and mechanical properties.

To produce three-dimensional products from the pulp, the fibers are suctioned via a suction tool, where the fibers then adhere to the surface (suction surface) of a suction body, which substantially corresponds to the geometry of a product to be manufactured. In so doing, the suction also causes a dewatering of the suctioned fiber mat or the preform resulting therefrom. As a rule, such a moist preform has a moisture content of 50 to 70 wt. % after suction.

A device and a manufacturing method for manufacturing products from fibers are known from DE 10 2019 127 562 A1, for example.

After the fibers have been suctioned, it has been suggested to pre-press the fiber mat in order to further dewater and strengthen it. For this purpose, it is also known to spray the underside of the suction tool with water using a spray bar in order to remove or align fibers in the edge section of the suction body so that the fiber mats have a smooth edge formation without fringes etc. even before pre-pressing, which consequently improves the formation of the edge of fiber-containing products in the subsequent manufacturing method.

When fibers are suctioned, especially two types of undesirable fiber deposits can arise that remain throughout subsequent processing and lead to protruding fibers in the edge section of the finished product. The fibers that collect on the suction surface during suction in the cavity of a suction body of the suction tool and form a composite there, show a tendency in the edge section to settle along the direction of movement on a stripping edge (type I). In order to remove fiber protrusions on an inner edge of the cavity, pre-pressing bodies of a pre-pressing tool can have a lip that pushes protruding fibers along the stripping edge towards the cavity. If fibers protrude beyond the area in which the lip grips into the edge section, it pinches them off. This results in fiber protrusions. These usually remain throughout the process and ultimately lead to excess fiber on the outer edge of the final product. The excess appears there in the form of frayed and wavy edges.

During suctioning, the suction tool dips into a pulp tank in the direction of the bottom. When leaving this tank, another form of undesirable fiber deposits (Type II) arises, where fiber lumps from the pulp are deposited on the tool surface. If lumps settle in the edge section of the cavities, they are usually also clamped by the lip of a pre-pressing body. The resulting overhangs remain throughout the process and form large protrusions on the final product.

However, known designs of a spray bar do not ensure reliable cleaning of a product edge section since a spray bar only moves along a linear axis from the upper cavity end to the lower one. The linear axis leads to different relative speeds at the differently aligned stripping edges. An edge that is aligned perpendicular to the movement of the spray bar is generally cleaned less reliably than an edge that runs horizontal to the spray axis movement.

Furthermore, it is not possible to specifically clean the edge section of cavities with a spray bar. Instead, a carrier plate for the cavities is sprayed completely, along with all the cavities installed thereon. Depending on the size and number of installed cavities, only a comparatively small part of a jet falls on the critical edge section. This also means that the interior section of the cavities that are already filled with fibers at this point, are sprayed with the jet. This resoftens the fibers. Furthermore, lumps of fibers can come loose and partially deposit in the edge section that was originally supposed to be freed of fibers. Furthermore, such a fiber displacement not only causes the contamination of the edge section but also a contamination of the machine compartment.

As a result, it is therefore still necessary to rework the edges of such products. Furthermore, a high use of resources (water, energy, etc.) and complex machine design are required. Ultimately, this leads to a major soiling of machines and machine components.

SUMMARY

Object

In contrast thereto, it is an object to provide a solution that eliminates the disadvantages of the prior art. It is another object to optimize the edge formation as early as possible in a fiber processing process. Furthermore, it is an object to keep the effort and installation space for edge formation low. Moreover, it is an object to keep the use of resources low.

Solution

The above-mentioned objects are achieved by a tool for processing fiber-containing material for the production of three-dimensional products, having a mold body with a three-dimensional surface that substantially reflects the shape of a product to be molded, where the mold body has a peripheral edge section, further having a spray arrangement via which a medium for aligning fibers in the edge section of the mold body and/or for aligning fibers in an edge section of an opposing tool with an further mold body can be dispensed.

The integration of a spray arrangement into the tool (suction tool or pre-pressing tool) for processing fibers offers the advantage of discharging a medium as a media flow in a targeted manner and bringing it to a section that is essential for edge formation. This means that irrelevant sections are not sprayed, and the spraying only strikes the relevant sections in the desired alignment and strength for the given application.

The employed medium can be, for example, water, a gas or gas mixture (e.g., air) or an air-water mixture. In other embodiments, other media (liquids) or additives for the above-described media can also be used, in order for example to influence the connection of fibers and/or (barrier) properties.

The media flow exiting via the spray arrangement, which for example can have several outlets, can be directed, for example, onto another opposing tool so that the fibers on the opposing tool can be pressed into a cavity in an edge section. Alternatively or additionally, fibers that protrude beyond an edge section on the opposing tool can be sprayed away. As a result, a clear edge is formed without protruding fibers. During subsequent processing, the edge only becomes drier and firmer so that no impairment of edge formation thereby occurs. Accordingly, final products have an edge formation without fraying.

The spray arrangement can be designed in such a way that a media flow emerging via, for example, several outlets specifically strikes sections of, for example, an opposing tool and fibers, and thereby deflects and/or moves them.

The outlets themselves can be designed in other embodiments, for example as nozzles. Instead of nozzles, simple holes, slots, etc. can also be outlets that enable “spraying”.

In other embodiments, the mold body and the further mold body of an opposing tool can be designed differently. For example, a corresponding pair of tools can be a suction tool and a pre-pressing tool. Instead of completely spraying the underside of a suction tool with the aid of a spray bar after suction, as previously known from the prior art, a media flow is dispensed via the spray arrangement on one of the tools at a determinable distance between the pre-pressing tool and the suction tool. Since the two tools are coordinated with each other with regard to the design of the products to be manufactured, the media flow in the edge section always strikes a corresponding edge section of the opposing tool. Furthermore, in one of the two tools, the spray arrangement and the amount of dispensed medium can be specifically tailored to the design of the other tool corresponding to the alignment of outlets, e.g., nozzles.

In other embodiments, the spray arrangement can have outlets that are arranged at regular intervals so that uniform spraying can take place.

In other embodiments, the spray arrangement can have a common reservoir for providing a medium for the outlets (e.g., nozzles) so that pressure equalization is provided, and the pressure or media output is uniform at all outlets.

In other embodiments, the spray arrangement can have at least one supply to the reservoir. In still other embodiments, multiple feeds can be provided that are evenly, preferably arranged symmetrically distributed so that the delivery of a uniform media flow at all outlets is further supported.

In other embodiments, the spray arrangement can have at least one deflection arrangement for deflecting and/or fanning out an emerging media flow. The deflection arrangement can, for example, have a deflection tongue. This makes it possible to fan out a media flow. In addition, this allows the direction of the dispensed media flow to be set with regard to the design of a corresponding tool (opposing tool).

In other embodiments, the deflection arrangement can have a continuous deflection edge running parallel to the edge section of the mold body. The deflection arrangement can, for example, have a circumferential deflection edge. The deflection edge can be designed in such a way that a circulating media flow is emitted via outlets of the spray arrangement, which, like a “curtain,” strikes the edge section of an opposing tool substantially evenly.

In other embodiments, the deflection arrangement can have a deflection angle for a media flow exiting the spray arrangement of 0 to 85° relative to the exit direction.

In other embodiments, the deflection arrangement can have a plurality of deflection tongues. Each outlet (e.g., nozzle) can be assigned a deflection tongue. The exiting and deflected or fanned out media flows can overlap in sections, where overall, a “curtain” can also be formed.

In other embodiments, outlets can be designed as holes in the spray arrangement, and/or the outlets can be nozzles, in particular two-fluid nozzles and/or tongue nozzles. The formation of outlets as holes allows for individual and simple design. For example, holes can be introduced into a ring that has a common supply line (reservoir) for a medium. The arrangement and design of the openings (diameter, cross-section, exit angle and orientation relative to an opposite spray surface) can be specifically adjusted. Tongue nozzles have the advantage that they allow a fanning out of an exiting media flow.

In further embodiments, the mold body can have a stripping lip in the edge section. Such a stripping lip enables, for example, scraping off protruding fibers when closing the pre-pressing tool of a pre-pressing station, where a pre-pressing tool with at least one pre-pressing body and a suction tool with at least one suction body are moved relative to each other. As the distance between the suction body and the pre-pressing body decreases, for example a circumferential stripping lip, which can include a flexible material (e.g., silicone), can come into contact with the edge section of the suction body in the edge section. Any remaining fibers that protrude beyond the edge section of a suction surface of the suction body after spraying are scraped off, and the edge of the fiber mat is pressed. A suction tool usually has a suction surface with a plurality of openings by which the fibers and liquid of a pulp are suctioned. The suctioned liquid is discharged via channels in the suction tool. In the edge section, a ring surrounds the suction surface, where the inside of the ring defines the outer edge of the fiber mat/preform and accordingly of the product to be produced. The stripping lip can have an outer diameter that substantially corresponds to the inner diameter of the ring so that the stripping lip can dip into the ring and scrape off the fibers as well as press the edge of the fiber mat. To facilitate the “dipping” of the stripping lip into the ring, the ring can have a dipping section with a larger diameter. The stripping lip can have a varying diameter at its outer edge with respect to the closing direction, which supports the scraping off and pressing of fibers. In other embodiments, the height of the stripping lip can be at least as large as the height of a ring in the closing or pressing direction.

In other embodiments, the tool can be a pre-pressing tool for pressing three-dimensional preforms or suctioned fibers/fiber mats made of a fiber-containing material and the mold body can be a pre-pressing body, where the three-dimensional surface is a pressing surface of the pre-pressing body, and where the pre-pressing body includes a flexible material (e.g., silicone or silicone-containing plastic mixture).

In other embodiments, the tool can be a suction tool for suctioning fibers from a fiber-containing suspension, and the mold body can be a suction body, where the three-dimensional surface is a suction surface of the suction body.

The above-mentioned object is also achieved by a molding plant for manufacturing fiber-containing products, having a pre-pressing station for pressing three-dimensional preforms made of a fiber-containing material with at least one pre-pressing tool and a suction station with at least one suction tool, where at least one spray arrangement is arranged on the at least one pre-pressing tool or the at least one suction tool, and outlets of the at least one spray arrangement are aligned with an edge section of the at least one opposite suction tool or the at least one opposite pre-pressing tool.

A molding plant with an integrated spray arrangement in a tool (suction tool or pre-pressing tool) offers the above-described advantages and enables faster processing by shortening the cycle time because spraying takes place during the closing of a suction tool and a pre-pressing tool. In the prior art, spraying is carried out as a separate process step before closing opposing tools that requires cycle time. Furthermore, the integration of the spray arrangement offers optimal alignment and spraying of fibers since there is no overspray of points that are not needed (e.g., underside of the carrier plate tool and fiber mat outside the edge section). In addition, the outlets of a spray arrangement can be specifically aligned and designed to the design of suction bodies and individually to products without compromise solutions.

In other embodiments, a molding plant can have at least one pre-pressing tool that is designed according to one of the above embodiments, or at least one suction tool that is designed according to one of the above embodiments.

In other embodiments, a molding plant can have a device for supplying media, which has at least one actuator for controlling the supply of media to the at least one spray arrangement, where the at least one actuator is arranged directly in front of a reservoir for providing a medium within the spray arrangement and/or directly in front of openings of the spray arrangement. The actuator can be, for example, a valve, a motor, a throttle valve, etc. The immediate arrangement of the actuator in front of a reservoir or the openings of the outlets of the spray arrangement allows a rapid response of the outlets to deliver a media flow. In addition, this can make controlling the actuator easier.

In other embodiments, the suction surface of the suction body and suction channels in the edge section for suctioning fibers can have different permeabilities for a reduced suction effect compared to the rest of the suction body. The different permeability can be achieved by a different design and distribution of openings in the suction surface (e.g., a mesh structure of a suction tool that rests on a suction surface of a suction body, where the suction body has suction channels). For example, the edge section of a suction surface in particular can have a smaller number of openings and/or a smaller opening width as well as different cross-sections at the openings than the remaining area of a suction surface so that overall fewer fibers are suctioned in the edge section, and there is also less protruding and excess fiber material. The section in which fewer fibers are suctioned can explicitly refer only to an outer edge section so that the edge of a product to be formed does not necessarily have to be thinner than the remaining area of the product.

The above-mentioned object is also achieved by a method for manufacturing fiber-containing products having a pre-pressing station for pressing three-dimensional preforms made of a fiber-containing material with at least one pre-pressing tool and a suction station with at least one suction tool, where at least one spray arrangement is arranged on the at least one pre-pressing tool or the at least one suction tool, and outlets of the at least one spray arrangement are aligned with an edge section of a suction body of the at least one opposite suction tool or a pre-pressing body of the at least one opposite pre-pressing tool, where a medium (media flow) is cyclically dispensed via the outlets in accordance with a control via an actuator when the distance between the suction surface of the suction tool and the pressing surface of the pre-pressing tool reaches a value between 1 and 30 mm.

The spraying of the fibers in the edge section of an opposing tool already takes place before the surfaces of the opposing tools touch each other. In particular, the delivery of a medium via the outlets (e.g., nozzles) can also be terminated before the surfaces of the opposing tools touch each other. The distance between the tools allows the edge section of an opposing tool to be exposed to a uniform media flow, where the influence of overlaps of the media flows of adjacent outlets, especially in the case of fan-shaped media flows, on the overall media flow is low.

In other embodiments, the media flow can be dispensed as a flat jet.

In other embodiments, the relative pressure for providing the media flow can be between 0.1 and 10 bar, preferably between 1 and 3 bar.

In other embodiments, the media flow can be dispensed for a period of 0.5 to 5 seconds in accordance with a relative movement of the pressing surface of the pre-pressing body of the at least one pre-pressing tool and the suction surface of the suction body of the at least one suction tool. In other embodiments, the duration and pressure of the media flow output is determined according to the distance between opposing surfaces of the involved tools.

The solution presented here enables material savings in the manufacture of products made of a fiber-containing material since only as much material (fibers) is suctioned at the edge as is actually needed. Moreover, a faster manufacturing method is provided since no interruption/waiting time is required as is necessary with classic prior art spray bars. Furthermore, less water is used because the spraying is targeted. Furthermore, there is no contamination of a molding plant or dilution of the pulp by spray water bouncing or dripping off as in the prior art when using spray bars. In addition, punching is no longer required since perfect edge quality is provided. Finally, a stable edge is provided since the edge is shaped, that is, the fibers in the edge are bound while a punch creates “angel hair” (loose fibers).

Further features, embodiments and advantages result from the following illustration of exemplary embodiments with reference to the figures.

BRIEF DESCRIPTION OF THE FIGURES

In the figures:

FIG. 1 depicts a schematic representation of a molding plant for manufacturing products from a fiber material, according to some embodiments.

FIG. 2 depicts a schematic representation of suction tool and a pre-pressing tool in cross-section, according to some embodiments.

FIGS. 3-7 depict different designs of nozzle arrangements in a suction tool or a pre-pressing tool, according to some embodiments.

FIG. 8 depicts a schematic representation of an embodiment of a nozzle arrangement in a pre-pressing tool, according to some embodiments.

FIGS. 9-11 depict various representations of an embodiment of a nozzle arrangement in a pre-pressing tool, according to some embodiments.

FIG. 12 depicts schematic representations of the formation of a tongue and the dispensed medium via the nozzle arrangement, according to some embodiments.

FIG. 13 depicts a method for the manufacture of three-dimensional products from a fiber-containing material, according to some embodiments.

DETAILED DESCRIPTION

Various embodiments of the technical teaching described herein are shown below with reference to the figures. Identical reference signs are used in the figure description for identical components, parts and processes. Components, parts and processes that are not essential to the technical teachings disclosed herein or that are obvious to a person skilled in the art are not explicitly reproduced. Features specified in the singular also include the plural unless explicitly stated otherwise. This applies in particular to statements such as “a” or “one.” The exemplary embodiments shown here do not represent any restriction with regard to further embodiments and modifications of the described embodiments.

FIG. 1 shows a schematic representation of a molding plant 1000 for manufacturing three-dimensional products from a fiber material, according to some embodiments. The fiber material for production can be provided by a fiber processing plant and made available to the molding plant 1000. The provision and the making available can for example take place via supply lines, in which liquid pulp is fed from a fiber preparation plant to a storage container or pulp tank 200 of the molding plant 1000, for example continuously or discontinuously. Alternatively, pulp can be prepared in a pulp tank 200 of the molding plant 1000. For this purpose, for example, water and fibrous materials and, if necessary, additives can be introduced into a pulp tank 200 via a liquid supply, and the pulp can be treated in the pulp tank 200 by mixing the individual components under heat input and by auxiliary means, such as an agitator.

Pulp refers to an aqueous solution containing fibers, where the fiber content of the aqueous solution can be in a range of 0.5 to 10 wt. %. In addition, additives such as starch, chemical additives, wax, etc. can be present. The fibers can be, for example, natural fibers, such as cellulose fibers, or fibers from a fiber-containing original material (for example waste paper).

The molding plant 1000 can be used to produce, for example, biodegradable cups, capsules, trays, plates, and other molded and/or packaged parts (e.g., as holder/supporting structures for electronic appliances). Since a fibrous pulp with natural fibers is used as the starting material for the products, the products manufactured in this way can themselves be used as a starting material for the manufacture of such products after their use, or they can be composted, because they can usually be completely decomposed and do not contain any substances that are harmful to the environment.

The molding plant 1000 shown in FIG. 1 has a frame 100 that can be surrounded by a cladding. The supply units 300 of the molding plant 1000 include, for example, interfaces for the supply of media (for example, 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., and interfaces for bidirectional communication via a wired and/or wireless data connection. Instead of a wired data connection, there can also be a data connection via a fiber optic line. The data connection can be, for example, between the control unit 310 and a central controller for multiple molding plants 1000, to a fiber preparation plant, to a service point, and/or subsequent devices. It is also possible to control the molding plant 1000 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 that displays operating data and states of the molding plant 1000 for selectable components or the entire molding plant 1000. The display can be designed as a touch display so that adjustments can be made manually by an operator of the molding plant 1000. Additionally or alternatively, further input means, such as a keyboard, a joystick, a keypad, etc. for operator inputs, can be provided on the HMI panel 700. In this way, settings can be changed and the operation of the molding plant 1000 can be influenced.

The molding plant 1000 has a robot 500. The robot 500 is designed as a so-called 6-axis robot and is thus able to pick up parts within its radius of action, to rotate them and to move them in all spatial directions. Instead of the robot 500 shown in FIG. 1, other handling devices can also be provided that are designed to pick up and twist or rotate products and move them in the various spatial directions. In addition, such a handling device may also be otherwise configured, in which case the assembly of the corresponding stations of the molding plant 1000 may differ from the exemplary embodiment shown.

A suction tool 520 is arranged on the robot 500. In the exemplary embodiment shown, the suction tool 520 has cavities formed as negatives of the three-dimensional molded parts to be formed, such as of cups 3000, as suction cavities. The suction cavities can have, for example, a net-like surface as a suction surface 532 on which fibers from the pulp are deposited during the suction. Behind the net-like surfaces, the suction cavities are connected to a suctioning device via suction channels 536 in the suction tool 520. The suctioning device can be realized, for example, by a suction device 320. Pulp can be suctioned in via the suctioning device when the suction tool 520 is located within the pulp tank 200 in such a way that the suction cavities are at least partially located in the aqueous fiber solution-the pulp. A vacuum or a negative pressure for suctioning fibers, when the suction tool 520 is located in the pulp tank 200 and the pulp, can be provided via the suction device 320. For this purpose, the molding plant 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 in the supply units 300 to the suction tool 520 and the openings in the suction cavities. Valves are arranged in the lines, which can be controlled via the control unit 310 and thus regulate the suction of the fibers. It is also possible for the suction device 320 to perform a “blow-out” instead of a suction, for which purpose the suction device 320 is switched to another operating mode in accordance with its design.

In the production of molded parts made of 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, so that fibers are suctioned out of the pulp and are deposited on the suction surface 532, for example on a mesh of the suction cavities of the suction tool 520.

Thereafter, the robot 500 lifts the suction tool 520 out of the pulp tank 200 and moves it together with the fibers adhering to the suction cavities 532, which still have a relatively high moisture content of, for example, over 80 wt. % of water, to the pre-pressing station 400 of the molding plant 1000, where the negative pressure is maintained in the suction cavities for the transfer. The pre-pressing station 400 has a pre-pressing tool 410 with pre-pressing bodies. The pre-pressing bodies can be formed, for example, as a positive of the molded parts to be manufactured and have a corresponding size with regard to the shape of the molded parts for receiving the fibers adhering in the suction cavities.

During the production of products, the suction tool 520 is moved, with the fibers adhering in the suction cavities, to the pre-pressing station 400 in such a way that the fibers are pressed into the suction cavities. The fibers are pressed together in the suction cavities, so that a stronger connection is thereby produced between the fibers. In addition, the moisture content of the preforms formed from the suctioned-in fibers is reduced, so that the preforms formed after the pre-pressing only have a moisture content of, for example, 60 wt. %. To squeeze out water, flexible pre-pressing bodies can be used, which are inflated, for example, by means of compressed air (method air), thereby pressing the fibers against the suction surface 532 of the suction cavities. As a result of the “inflation,” both water is squeezed out, and the thickness of the sucked-in fiber layer is reduced. The liquid or pulp discharged during pre-pressing is sucked off via the suction tool 520 and can, for example, be reused.

After pre-pressing in the pre-pressing station 400, the thus produced preforms on the suction tool 520 are moved by the robot 500 to a hot-pressing station 600, which has a molding tool 610 for the final shaping and drying of the preforms to form three-dimensional products. For this purpose, the negative pressure is maintained at the suction tool 520 so that the preforms remain in the suction cavities. The preforms are transferred via the suction tool 520 to a lower tool body of a first tool component of the molding tool 610, which can be moved along the production line and out of the hot-pressing station 600. If the lower tool body is in its extended position, the suction tool 520 is moved to the lower tool body in such a way that the preforms can be placed on forming devices or forming parts of the lower tool body. Subsequently, an overpressure is produced via the openings in the suction tool 520 so that the preforms are actively deposited by the suction cavities in the suction tool 520, or the suction is ended, so that the preforms remain on the forming devices or forming parts of the lower tool body due to gravity. By providing overpressure at the openings of the suction cavities of the suction tool 520, pre-pressed preforms resting/adhering in the suction cavities of the suction tool 520 can be released and dispensed.

Thereafter, the suction tool 520 is moved away via the robot 500 and the suction tool 520 is dipped into the pulp tank 200 in order to suction subsequent fibers for the production of molded parts from fiber-containing material.

After the transfer of the preforms, the lower tool body of the molding tool 610 moves into the hot-pressing station 600. In the hot-pressing station 600, the preforms are pressed into finished products under heat and high pressure, for which purpose an upper tool body of a second tool component of the molding tool 610 is brought onto the lower tool body via a press. The upper tool body has cavities corresponding to the forming devices or forming parts. After the hot pressing operation, the lower tool body and the upper tool body are moved away relatively from one another and the upper tool body is moved along the molding plant 1000 in the manufacturing direction, where after the hot pressing the manufactured products are suctioned via the upper tool body and accordingly remain within the cavities. Accordingly, the manufactured products are brought out of the hot pressing station 600 and deposited via the upper tool body after the method on a transport belt of a conveyor device 800. After the deposition, the suction via the upper tool body is ended and the products remain on the conveyor belt. The upper tool body moves back into the hot pressing station 600 and a further hot pressing operation can be carried out.

The molding plant 1000 subsequent has a conveying device 800 with a transport belt. The manufactured products made of fiber-containing material can be placed on the transport belt after the final molding and the hot pressing in the hot-pressing station 600, and discharged from the molding plant 1000. In further embodiments, after placing the products on the transport belt of the conveying device 800, further processing can take place, such as filling and/or stacking the products. The stacking can take place, for example, via an additional robot or another device.

The molding plant 1000 from FIG. 1 shows a possible embodiment. A molding plant according to the technical teaching described herein can also have only one forming station with a replaceable tool, e.g., a suction tool 520 or a hot press tool, in which fiber-containing material can be processed, where different tools for manufacturing different three-dimensional products can be received in the at least one forming station. The subsequent stations and devices shown for the molding plant 1000 of FIG. 1 are not absolutely necessary for implementing the technical teaching.

FIG. 2 shows a schematic representation of a suction tool 520 and a pre-pressing tool 410 in a sectional view, according to some embodiments, where the rough structure is shown. A spray arrangement designed as a nozzle arrangement 900 for spraying fibers is described in detail below with reference to FIGS. 3 to 13.

The suction tool 520 has a base body with a carrier plate 522 on which a suction body 530 is arranged. The suction body 530 has suction channels 536 and openings 534 that extend over the surface or the suction surface 532. The suction channels 536 and the openings 534 are connected to each other and serve to suction fibers when the suction tool 520 is immersed in a pulp. Furthermore, a fiber mat of suctioned fibers that are deposited on the suction surface 532 can be held in the suction cavity by maintaining a negative pressure via the openings 534 and suction channels 536. In other embodiments, a net or a similar structure (mesh) can be arranged on the inner surface of the suction body 530, which then serves as a suction surface 532 and on which the fibers collect. The arrangement and design of a mesh, the openings 534 and the suction channels 536 are selected such that fewer fibers are suctioned in the outer edge section on the suction surface 532 than in the remaining section of the suction surface 532. The outer edge section is the section in the immediate vicinity of a ring 540. The ring 540 surrounds the suction surface 532 and defines the outer edge of a product to be formed. There may be fewer openings 534 and suction channels 536 in the outer edge section, and/or the diameters of the openings 534 and the suction channels 536 may be smaller than in the remaining section of the suction surface 532. In other embodiments, additionally or alternatively, a net or a similar structure in an outer edge section of a suction surface 532 can have a smaller number of openings, or fewer sections may be formed in a net-like manner.

The ring 540 defines an outer edge for a product to be formed on its inner circumference. In an entrance area for a silicone body 426 of the pre-pressing tool 410, the ring 540 has a stripping edge 542. The stripping edge 542 extends over the entire circumference of the ring 540.

The components of the suction tool 520 can, for example, be made of a metal (e.g., aluminum) or a metal alloy.

The pre-pressing tool 410 has a support body 420 made of a metal (e.g., aluminum) or a metal alloy. At a pre-pressing section of the pre-pressing tool 410, the support body 420 has an elevation on which a silicone body 426 is arranged. The silicone body 426 and the support body 420 together form a pre-pressing body for a pre-pressing tool 410. The support body 420 has an air channel 422 in its interior, which merges into secondary channels so that by providing a medium such as compressed air, the silicone body 426 can be inflated, and this exerts additional pressure on the fiber material in the cavity of the support body 420 for pressing and dewatering the fiber mat. The silicone body 426 can additionally be perforated. The support body 420 is connected to a carrier plate 412 of the pre-pressing tool 410. Instead of a silicone body 426, a pre-pressing body can have a flexible material that has the same properties as silicone and causes expansion upon the application of pressure. Thermoplastic elastomers or others can be used for this purpose.

The silicone body 426 has a stripping lip 430 on the upper outer circumference. When closing the components shown in FIG. 2, the pre-pressing tool 410 and suction tool 520, this scrapes off fibers protruding from the edge section of the suction surface 532 or the ring 540 and can push fibers specifically into the edge section of the suction surface 532. The flexibility of the silicone body 426 supports the scraping and pushing of fibers in this section. Furthermore, this brings about a pressing or pre-pressing so that any deficit of fibers in the outer edge section of the suction surface 532 is compensated by “edge” fibers that are pushed over the stripping lip 430 along the stripping edge 542 into the outer edge section. After reaching an end position, the fibers are pressed over the silicone body 426.

In other embodiments, a suction tool 520 can be designed as a multi-cavity tool and have multiple suction bodies 530. A corresponding pre-pressing tool 410 can also be designed as a multi-cavity tool and have a corresponding plurality of pre-pressing bodies or silicone bodies 426 and support bodies 420.

In the following, embodiments of spray arrangements are described that, in the shown embodiments, are designed as nozzle arrangements 900, where in other embodiments, spray arrangements can also have other outlets such as the shown nozzles 922.

FIG. 3-7 show various embodiments of nozzle arrangements 900 as can be designed for spraying fibers. In this case, a nozzle arrangement can be provided on a suction tool 520 or a pre-pressing tool 410.

FIG. 3 shows an embodiment with a nozzle arrangement 900 on a pre-pressing tool 410, according to some embodiments, where nozzles of the nozzle arrangement 900 are provided in an edge section of the silicone body 426. For this purpose, the silicone body 426 is partially opened so that the nozzles provided all around can dispense a medium that strikes the ring 540 and the stripping edge 542 in order to spray fibers in the stripping section of the ring 540. The nozzle arrangement 900 has a plurality of nozzles or a circumferential nozzle slot. The nozzles are designed as bores in a nozzle ring that runs in the edge section of the silicone body 426. Below the nozzle ring, an annular reservoir 928 is located in the support body 420. The reservoir 928 is connected to a connection for the media supply and serves to equalize the pressure across all nozzles of the nozzle arrangement. Due to the design of the shown embodiments, a concentric pressure equalization takes place here via the reservoir 928. In addition, pressure loss regulation is achieved via the reservoir 928.

FIG. 4 shows an embodiment with a nozzle arrangement 900 that has a nozzle ring 920 that is provided on the outer edge of a silicone body 426 of a pre-pressing tool 410, according to some embodiments. The nozzle ring 920 has a reservoir 928 for providing a medium for spraying fibers. Furthermore, the nozzle ring 920 has a plurality of nozzles 922 or a circumferential nozzle slot. The nozzle arrangement 900 has a deflection device for deflecting the media flow output via the nozzles 922, where the surface of the silicone body 426 does not require any openings for the nozzle arrangement 900, and the pressing surface of the silicone body 426 is therefore not reduced. As shown, this allows a media flow to be output to the scraping section of the ring 540.

FIG. 5 shows an embodiment with a nozzle arrangement 900 that has a nozzle ring arranged on the support body 420 of the pre-pressing tool 410, according to some embodiments. The arrangement and design of the nozzle ring of FIG. 5 differs from the embodiment according to FIG. 4 in particular in that the output media flow or jet is not deflected by a deflection device, but strikes the opposite scraping section of the ring 540 substantially in a straight line.

FIG. 6 shows an embodiment with a nozzle arrangement 900 that is integrated in the suction tool 520, according to some embodiments. The nozzle arrangement is formed in the suction body 530 and, in addition to the reservoir 928, has a plurality of nozzles or a circumferential nozzle slot that open into the edge section of the suction surface 532 at an outer edge and can directly spray off protruding fibers.

FIG. 7 shows an embodiment with a nozzle arrangement 900 that is arranged on the outside of the ring 540 on the suction tool 520 and can have a plurality of nozzles or a circumferential nozzle slot, according to some embodiments. The nozzles are directed towards the suction surface 532 or the interior of the suction cavity so that fibers in the stripping section of the ring 540 can be flushed into the suction cavity. Additional medium such as water can be sucked out via the openings 534 and suction channels 536.

The embodiments shown in FIGS. 3 to 7 have the advantage that, compared to known systems for spraying fibers from the prior art, such as spray bars, a medium is only introduced into the actually required section, and the jet is adapted to the given geometry so that this allows a significant improvement to be achieved with less use of resources (e.g., spraying medium). Furthermore, the shown embodiments allow spraying during a closing movement of two corresponding tools, the suction tool 520 and pre-pressing tool 410, which is already taking place, so that no additional time is required for spraying that is absolutely necessary, for example, with a spray bar.

FIG. 8 shows a schematic representation of an embodiment of a nozzle arrangement 900 on a pre-pressing tool 410, according to some embodiments, which is based on the concept shown in FIG. 4. FIG. 8 shows a more detailed representation of a nozzle ring 920 that has a plurality of nozzles 922 that are evenly arranged at defined intervals. The nozzles 922 are connected to a reservoir 928 that is supplied with a medium via at least one connection 924 (see FIG. 9-11). In the supply to the connection 924, there is at least one actuator, for example a valve, that is arranged immediately in front of the reservoir 928 in order to ensure a rapid response when the valve is opened or closed. In other embodiments, a reservoir 928 can be arranged below the support body 420. In still other embodiments, nozzles 922 can be aligned straight upwards, i.e., vertically.

The nozzle arrangement 900 has a tongue ring 930 that serves as a deflection arrangement for medium exiting the nozzles 922. In the shown exemplary embodiment, the nozzles 922 are designed as bores so that a substantially straight jet of medium initially emerges from them. For spraying, it is advantageous if this is done completely around the circumference, where a water jet or the like not only strikes sections, but forms a closed spray wall as a “curtain”. Especially for products with a round cross-section, as shown here in the figures, the formation of a spray wall is a challenge that can be solved by the tongue ring 930. The embodiments and effects of a tongue ring 930 are described in FIG. 12. The nozzle ring 920 and the tongue ring 930 surround the support body 420 on the circumference. In other embodiments, the nozzle ring 920 and the tongue ring 930 can be designed as one piece. In other embodiments, the nozzle ring 920 and/or the tongue ring 930 can also be formed together with a support body 420.

The tongue ring 930 and nozzle ring 920 can be made of a metal (e.g., aluminum) or a metal alloy.

FIG. 9-11 show various representations of another embodiment of a nozzle arrangement 900 on a pre-pressing tool 410 that is based on the concept shown in FIG. 4 and has the components of a nozzle arrangement 900 shown in FIG. 8.

The pre-pressing tool 410, including the silicone body 426 and the support body 420, forms a pressing surface 428 on the surface of the silicone body 426 for compacting and dewatering a fiber mat that is provided in a suction cavity of a suction tool 520. The geometry of the pre-pressing tool 410 and in particular of the silicone body 426 substantially corresponds to the geometry of the product to be molded.

In the interior, the support body 420 has at least one air channel 422 for supplying a gas or gas mixture (e.g., air), by means of which the silicone body 426 can expand (“be inflated”) due to its elastic design and, when the pre-pressing tool 410 and the suction tool 520 are in a closed state, exerts additional pressure on the fiber mat in the suction cavity. In the unpressurized state, i.e., when no gas or gas mixture is introduced, the silicone body 426 lies against the outer surface of the support body 420.

The silicone body 426 is connected to the tongue ring 930 via a tongue and groove connection with a suitable profile (e.g., dovetail profile). The tongue ring 930 lies on the support body 420 and is connected thereto as well as the nozzle ring 920 that circumferentially surrounds the tongue ring 930, the support body 420 and the silicone body 426. The nozzle ring 920 has a plurality of nozzles 922 arranged regularly around the circumference. The nozzles 922 are designed as bores. Depending on the dimensions of the tool and the product to be manufactured, the bores have a diameter of 0.5-1.5 mm. Furthermore, the employed medium and the distance between a pressing surface 428 and a suction surface 532 at which the spraying is to take place, as well as the heights H1, H2 (see FIG. 12) are decisive for determining the diameter. In the embodiment shown in FIGS. 9-11, the nozzles 922 have a length of approximately 8 mm and a diameter of 0.8 mm. The shown design for a product or fiber mat with a diameter of approximately 60 mm has a total of 36 holes as nozzles 922, which are evenly distributed. In other embodiments, two-fluid nozzles can also be provided instead of bores so that, for example, an air-water mixture is dispensed as a medium via the nozzle arrangement 900.

The nozzles 922 open into a reservoir 928 that is connected to at least one connection 924. The design in FIGS. 9 to 11 has four evenly distributed connections 924 for media supply. In other embodiments, the number of connections 924 can also differ from that shown, where, for example, only one connection 924 can be provided. The other end of the nozzles 922 for media dispensing is directed toward a deflection surface 934 of the tongue ring 930 that serves to deflect and fan out the dispensed media. A fanning out of the medium along the deflection surface 934 is achieved by rounding the tongue ring 930 (see FIG. 12).

As further shown in FIG. 10, an upper tongue edge of the tongue ring 930 protrudes in the radial direction from the stripping lip 430 extending thereabove so that a fanned-out jet 940 cannot strike the stripping lip 430 and the silicone body 426.

The height of the section of the silicone body 426 that runs from the upper tongue edge to the stripping lip 430 has a comparatively large height so that, on the one hand, during the relative displacement of the pre-pressing tool 410 and the suction tool 520 during closing, fibers can be scraped off early on and, on the other hand, there is a sufficiently large, compressible buffer for pressing in the edge section. A corresponding height for this section can be, for example, 0.8 to 0.9 times the height of the deflection surface 934. The deflection surface 934 has a length of 5-30 mm, depending on the design of the tool and the product to be manufactured, where in the exemplary embodiments shown in FIGS. 9-11, the length of the deflection surface 934 is 5 mm.

The illustration in FIG. 11 shows the formation of channels 910 that extend circumferentially in regular sections around an outer edge section of the nozzle ring 920 of the nozzle arrangement 900. The outer edge section of the nozzle ring 920 surrounds a channel 912 into which the ring 540 can dip when the pre-pressing tool 410 and the suction tool 520 are in a closed state. In addition, water pressed out of a fiber mat as well as spray water can be removed via the channel 912. As a rule, however, spray water that strikes the edge section of a fiber mat in the edge section of the suction surface 532 is suctioned via the openings 534 and suction channels 536 and accordingly cannot reach the machine compartment of a molding plant 1000 or a pulp tank 200, which would affect the concentration of the pulp or contaminate the molding plant. The pre-pressing tool 410 with the nozzle arrangement 900 can be fastened to a carrier plate 412 by means of screws via the indicated holes.

FIG. 12 shows schematic representations of the formation of a tongue 932 and the dispensed medium via the nozzle arrangement 900, according to some embodiments. The embodiments shown in the figures refer to substantially rotationally symmetrical products and correspondingly designed tool components. However, spraying edge sections can also be done with on straight edge sections, where special tongue nozzles or other devices such as deflection surfaces can be provided to form a “jet wall” of medium. Due to the curvature in the edge section, the embodiments described herein require a corresponding deflection of the dispensed medium in addition to a fanning out to provide a flat jet.

A flat jet is achieved by the curvature of the deflection surface 934 parallel to the vertical axis through the air channel 422 together with the radius of the tongue ring 930 that runs concentrically around the vertical axis. The medium striking the deflection surface 934 is deflected in two directions by the curvature of the deflection surface 934 since the medium follows the curvature of the surface on that the medium strikes. The upper part of the tongue ring 930 has a sharp tear-off edge that is referred to as tongue 932 and ensures that the deflection of the jet 940 by an angle n is maintained. The angle n is between 30° and 45° depending on the design and dimensions of the tools and the products to be manufactured. In the shown exemplary embodiment, the angle n is about 36°.

The lower illustration in FIG. 12 shows a schematic representation of the lateral deflection of the medium, where a fan-like jet formation results from the nozzles 922 due to the curvature of the deflection surface 934. This results in overlaps between neighboring jets 940 in sections 950. However, in the edges of a jet 940, this is weaker than in the middle section so that the overlap has no negative effects, and accordingly a substantially even jet (pressure) is dispensed over the entire length of the common jet, i.e., the jet wall. For this purpose, the formation of the curvature or deflection via the deflection surface 934 must be accordingly adapted. As a rule, lateral fanning occurs at an angle a that is greater than 50°. The total deflection can be calculated with respect to a height H1 between the outlet opening of nozzles 922 to a contact point, i.e., surface of the fiber material in the suction cavity in the edge section, or between the upper tongue edge or tear-off edge for the jet 940 and the surface of the fiber material in the suction cavity in the edge section.

The parameters for the formation of the nozzle arrangement 900 and the heights H1, H2 as well as the spray duration, the pressure and the starting point of the beginning of the spray in relation to the distance between the pressing surface 428 and the surface of the fiber material in the suction cavity in the edge section during a closing movement are to be determined and specified depending on the design and dimensions of products. Furthermore, the closing speed must be adapted to the spraying (starting point, duration, pressure, medium) and coordinated. In the shown embodiment, for example, with water as the medium, a spray pressure of about 3 bar can be set, and the spraying can take place for about 1 second. The distance between the surface of the fiber material in the suction cavity in the edge section and the corresponding pressing surface 428 is preferably 5 mm, where with respect to the start of the spraying or the media output, the output can be started when such a distance is reached and is stopped when the distance is less than 5 mm, or the media output can be started before the distance of 5 mm is reached and stopped when the distance of 5 mm is reached.

In other embodiments, the distance can be greater or less than 5 mm depending on the design of the products to be manufactured and the tool design resulting therefrom. Preferably, such a distance lies in the range between 3 and 15 mm, where a sufficient spraying effect can be achieved taking into account the deflection of the flat jet.

FIG. 13 shows a method 2000 for the production of three-dimensional molded parts from a fiber-containing material, according to some embodiments. The method 2000 can be used, for example, in a molding plant 1000 shown in FIG. 1.

The upstream method steps are the provision of pulp and tool components and, if necessary, a tool change for the production of the three-dimensional products. Subsequently, in a method step 2010, fibers are suctioned out of the pulp, where a suction tool 520 with suction bodies 530 that form suction cavities is dipped into the pulp. During suction by providing a negative pressure via openings 534 and suction channels 536 of the suction tool 520, fibers are deposited on the suction surface 532. Suctioned water is discharged via openings 534 and channels 536.

After the fibers have been suctioned, in a method step 2020, the suction tool 520 is moved out of the pulp and to a pre-pressing station 400, where a fiber mat formed by the suctioned fibers remains in the suction cavities by maintaining the negative pressure. During or thereafter, the suction tool 520 is aligned with a pre-pressing tool 410 that has pre-pressing bodies corresponding to the suction cavities. Thereafter in a method step 2030, a relative displacement of the suction tool 520 to the pre-pressing tool 410 takes place, where the distance between the surface of the fiber mat in the suction cavities and an opposite pressing surface 428 of the pre-pressing body is continuously reduced. After reaching a minimum distance between the free surface of the fiber mat in the suction cavities and the opposite pressing surface 428 of the pre-pressing bodies, a medium is output via a nozzle arrangement 900 in the edge section of the pre-pressing bodies, which medium strikes an opposite stripping edge 542 of the given suction tool 520 as a jet wall at an adjustable angle and thereby flushes fibers into the edge section of the fiber mat depending on the orientation and arrangement. The delivery of the medium is maintained for a definable period of time, e.g., 1 to 3 seconds with a relative pressure of 3 to 5 bar. Before the distance between the free surface of the fiber mat and the opposite pressing surface 428 of the pre-pressing body approaches “0” and the fiber mat touches the pressing surface 428, the spraying is terminated, and a stripping lip 430 of the pre-pressing body touches the stripping 542 of the suction cavities in a method step 2050 so that fibers are additionally pushed into the edge section of the fiber mat via the stripping lip 430. For this purpose, the stripping lip 430 is designed to be elastic and can be compressed or deformed and moved along the stripping edge 542 that preferably has an incline of at least 45 degrees (see FIGS. 2 to 7).

The fibers are then pressed in the suction cavities between the suction surfaces 532 and the pressing surfaces 428. In addition, a gas or gas mixture can be introduced into the pre-pressing bodies via an air channel 422 so that silicone bodies 426 of the pre-pressing bodies expand and exert additional pressure on the fiber material in the suction cavities to dewater the fiber mat and compact the fibers. At the same time, the discharged water continues to be suctioned via the openings 534 and suction channels 536 for removal.

Thereafter, in a method step 2060, the two tools, the suction tool 520 and pre-pressing tool 410, are opened, and the thereby pre-pressed preforms made of fiber-containing material in the suction cavities are transferred via the suction tool 520 in a method step 2070 to a subsequent station such as a hot-pressing station 600 with a molding tool 610. After hot pressing, subsequent forming steps and, if necessary, subsequent processing steps can be carried out.

LIST OF REFERENCE SIGNS

• • 100 Frame
  • 200 Pulp tank
  • 300 Supply units
  • 310 Control unit
  • 320 Suction device
  • 400 Pre-pressing station
  • 410 Pre-pressing tool
  • 412 Carrier plate
  • 420 Support body
  • 422 Air channel
  • 426 Silicone body
  • 428 Pressing surface
  • 430 Stripping lip
  • 500 Robot
  • 520 Suction tool
  • 522 Carrier plate
  • 530 Suction body
  • 532 Suction surface
  • 534 Opening
  • 536 Suction channel
  • 540 Ring
  • 542 Stripping edge
  • 600 Hot pressing station
  • 610 Molding tool
  • 700 HMI panel
  • 800 Conveying device
  • 810 Camera
  • 900 Nozzle arrangement
  • 910 Channel
  • 912 Channel
  • 920 Nozzle ring
  • 922 Nozzle
  • 924 Connection
  • 928 Reservoir
  • 930 Tongue ring
  • 932 Tongue
  • 934 Deflection surface
  • 940 Jet
  • 950 Section
  • 1000 Molding plant
  • 2000 Method
  • 2010-2070 Method steps
  • 3000 Cup