Mold body for a pre-pressing tool, and pre-pressing tool
20240218597 · 2024-07-04
Inventors
- Matthias Hausmann (Unken, DE)
- Werner Steinbacher (Piding, DE)
- Josef REHRL (Teisendorf, DE)
- Hubert REHRL (Teisendorf, DE)
- Marcel Boxleitner (Abtenau, AT)
- Thomas Schickmaier (Kremsm?nster, AT)
Cpc classification
D21J3/00
TEXTILES; PAPER
International classification
Abstract
The present disclosure relates to a molding station a mold body for a pre-pressing tool that is utilized for pressing three-dimensional preforms made of a fiber-containing material. The mold body includes a deformable material and is perforated in some portions.
Claims
1. A mold body for a pre-pressing tool for pressing three-dimensional preforms made of a fiber-containing material, wherein the mold body includes a deformable material and is perforated at least in portions.
2. The mold body according to claim 1, wherein the mold body substantially images a geometry of the preform on an outer surface.
3. The mold body according to claim 1, wherein the mold body has substantially a same wall thickness in wall and floor sections of the three-dimensional preforms.
4. The mold body according to claim 1, wherein the mold body has a larger radius at an inner surface in transitions from wall and floor sections than at a corresponding transition at an outer surface.
5. The mold body according to claim 1, wherein the mold body has a reduced material thickness at an inner surface in transitions from wall and floor sections.
6. The mold body according to claim 1, wherein the mold body is concave in wall and/or floor sections.
7. The mold body according to claim 1, wherein the mold body includes silicone.
8. The mold body according to claim 1, wherein a connection section of the mold body for the pre-pressing tool extends in an edge section for accommodating an edge of a preform.
9. The mold body according to claim 8, wherein the connection section has integrated edge ventilation for an edge of the preforms.
10. The mold body according to claim 1, wherein the mold body has an integrated connection unit in a connection section for a pre-pressing tool.
11. The mold body according to claim 10, wherein the connection unit includes a metal or a metal alloy.
12. The mold body according to claim 11, wherein the connection unit has at least one connection element.
13. The mold body according to claim 12, wherein the at least one connection element is or has a groove, threaded hole, pin, screw, or latching opening.
14. A pre-pressing tool having at least one mold body for pressing three-dimensional preforms made of a fiber-containing material, wherein the at least one mold body includes a deformable material and is perforated at least in portions, wherein the preforms have a moisture content of at least 50 wt. %, the tool having a first tool component having at least one support structure for the at least one mold body and a second tool component having a corresponding cavity, wherein, in the closed state of the pre-pressing tool, a mold cavity for pressing preforms is formed between an outer surface of the at least one mold body and an inner wall of the corresponding cavity.
15. The pre-pressing tool according to claim 14, wherein the at least one support structure has at least one channel via which a gas or gas mixture can be introduced between a surface of the at least one support structure and an inner surface of the at least one mold body in order to deform the support structure and press a preform introduced into the mold cavity against the inner wall of the corresponding cavity via the outer surface of the at least one mold body.
16. The pre-pressing tool according to claim 14, wherein the mold cavity has openings for discharging water that escapes from preforms during a pre-pressing process.
17. The pre-pressing tool according to claim 14, wherein the at least one mold body is detachably connected to a tool plate of the first tool component.
18. The pre-pressing tool according to claim 14, wherein the at least one mold body has a portion that immerses in the mold cavity in a connection section, which immersing portion is not used for pressing and, when immersing, causes fiber-containing material to push together in edge sections of the preforms.
19. The pre-pressing tool according to claim 18, wherein a height of the immersing portion is at least twice as great as a material thickness of the at least one mold body in a wall or base section.
20. The pre-pressing tool according to claim 14, wherein the at least one support structure for the at least one mold body is replaceably connected to a tool plate of the first tool component.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0086] In addition, further features, effects and advantages of the present disclosure are explained with reference to the attached drawing and the following description. Components which at least essentially correspond in terms of their function in the individual figures are identified by the same reference signs, with the components not having to be numbered and explained in all figures.
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DETAILED DESCRIPTION
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Mold Body for a Pre-Pressing Tool, and Pre-Pressing Tool
[0115] The production of fiber-containing products from a pulp generally takes place in several work steps. For example, fibers can be suctioned in a cavity of a suction tool, thus forming a preform. For this purpose, the pulp is provided in a pulp supply, and the suction tool is at least partially immersed in the pulp with at least one suction cavity whose geometry essentially corresponds to the product to be manufactured. During the immersion, suction takes place via openings in the suction cavity, which are connected to a corresponding suction device, wherein fibers from the pulp accumulate on the surface of the suction cavity. Alternatively, suction can be provided by means of scooping, wherein a scoop tool is immersed in the pulp and during startup fibers are deposited on molded parts of the scoop tool. After this, the suctioned fibers are pressed to form finished molded parts.
[0116] Thus, it is an object to provide a solution for forming products made of fiber containing materials which eliminates the problems of the prior art wherein products made of fiber containing materials have poor quality. It is another object to provide tooling for forming products made of fiber containing materials with high quality which does not have a negative effect on the forming process. It is a further object to provide a simple configuration of forming parts for manufacturing products made of fiber containing materials, wherein the costs relating to servicing, maintenance and operation are reduced.
[0117] The above-mentioned problem is solved by a mold body for a pre-pressing tool for pressing three-dimensional preforms made of a fiber-containing material where the mold body includes a deformable material and is perforated at least in portions.
[0118] As a result of the perforated design, gas or gas mixture introduced for deformation, such as compressed or ambient air, which primarily presses a preform against a corresponding wall of a cavity via the elastic mold body, can additionally penetrate a moist preform and in the process support the drainage during pressing. Furthermore, excessively high pressure can thus be prevented, such that the elastic mold body can be deformed more uniformly. As a result, preforms can thus be better drained because the pressure is distributed evenly over the entire surface and the air flow through the preform additionally discharges water due to the saturation of the preform.
[0119] In further embodiments, the mold body can substantially image the geometry of the preform on an outer surface. In this way, preforms that have been introduced can be pressed when a pre-pressing tool is closed, even before compressed air or the like is introduced in order to deform the elastic mold body.
[0120] In further embodiments, the mold body can have a substantially identical or uniform wall thickness in wall and floor sections of three-dimensional preforms. It is thus possible to deform the elastic material substantially uniformly. In this way it is possible to prevent sections of preforms from being pressed to different degrees and with differences in terms of time.
[0121] In further embodiments, the mold body can have a larger radius at an inner surface in transitions from wall and floor sections than at a corresponding transition at an outer surface. A substantially uniform wall thickness of the elastic mold body in the molding or pre-pressing section can thus also be provided in such transitions. Furthermore, this assists uniform deformation when the mold body is subjected to pressure, since the pressure or the deformation of the flexible material takes place uniformly with the adjacent sections, which generally have a flat and uniform extension. In embodiments with smaller radii on an inner side than on the outer side, a stronger deformation relative to the adjacent sections can occur on the outer side.
[0122] In yet further embodiments, the mold body can have a reduced material thickness at an inner surface in transitions from wall and floor sections, as a result of which the expansion is deliberately greater when compressed air or the like is introduced, such as in adjacent sections.
[0123] In further embodiments, the mold body can be concave in wall and/or floor sections. This allows the expansion of the molded part to be staggered when the mold body is deformed, in order to achieve specific wall or floor designs, for example. For example, it may be required to press these sections to a lesser degree because less fiber material is contained, for example at an edge.
[0124] In further embodiments, the mold body can be silicone or include silicone. Silicone has proven to be advantageous as a material for pre-pressing since it can be used within a wide temperature range and, depending on the mixture and design, is sufficiently flexible but at the same time withstands sufficient pressure for pre-pressing.
[0125] In further embodiments, the mold body can have, with respect to a wall section and floor section, a greater material thickness in a connection section for a pre-pressing tool. The connection section is the location at which the mold body is connected to a pre-pressing tool. High loads occur in the connection section when the tool closes, and therefore sufficient rigiditywhich also counteracts damageis thereby provided.
[0126] In further embodiments, a connection section of the mold body for a prepressing tool can extend in an edge section for accommodating an edge of a preform. The connection section can in this case also provide, for example, at least partly, a molding and pre-pressing section.
[0127] In further embodiments, the mold body can have an integrated connection unit in a connection section for a pre-pressing tool. The mold body can be connected or connectable to a tool component of a pre-pressing tool, for example a tool plate, via the connection unit. An integrated design includes, for example, embodiments in which the connection unit is completely or almost completely surrounded by the flexible material of the mold body.
[0128] In further embodiments, the connection unit can be or include a metal or a metal alloy. A connection unit designed in this way can, for example, enter into a form-fitting connection or an integral bond to a tool plate or the like.
[0129] In further embodiments, the connection unit can have at least one connection element. A (direct) connection to a tool component (for example, tool plate) can take place via the at least one connection element.
[0130] In further embodiments, the at least one connection element can be or have a groove, a threaded hole, a pin, a screw or a latching opening. Thus, for example, a mold body with a connection unit designed as a ring can be connected via screws and corresponding threaded holes to a tool component of a pre-pressing tool.
[0131] In further embodiments, the connection section can have integrated edge ventilation for an edge of preforms. Thus, for the pre-pressing, an additional air supply can thus be provided over the entire surface, such that preforms can be treated uniformly over the entire surface during the pre-pressing.
[0132] The aforementioned problem is also solved by a pre-pressing tool having at least one mold body according to any of the aforementioned embodiments for pressing three-dimensional preforms made of a fiber-containing material, wherein the preforms have a moisture content of at least 50 wt. %, the tool having a first tool component having at least one support structure for a mold body made of a deformable material and a second tool component having a corresponding cavity, wherein, in the closed state of the prepressing tool, a mold cavity for pressing preforms is formed between an outer surface of the mold body and an inner wall of the corresponding cavity.
[0133] In further embodiments, the at least one support structure can have at least one channel via which a gas or gas mixture (e.g. (compressed) air) can be introduced between a surface of the at least one support structure and an inner surface of the mold body in order to deform the support structure and press a preform introduced into the mold cavity against the inner wall of the cavity via the outer surface of the at least one mold body.
[0134] In further embodiments, the at least one cavity can have openings for discharging water that escapes from preforms during a pre-pressing process.
[0135] In further embodiments, the at least one mold body can be detachably connected to a tool plate of the first tool component. In this way, it is possible to replace specifically only mold bodies that are damaged or contaminated and have to be replaced or cleaned. It is therefore not necessary to replace, for example, a tool plate having a plurality of molding and support structures of a tool component.
[0136] In further embodiments, the at least one mold body can have a portion that immerses in the at least one cavity in a connection section, which immersing portion is not used for pressing and, when immersing, causes fiber-containing material to push together in edge sections of preforms. The edge formation of preforms can thus be considerably improved so that subsequent processing, such as spraying by means of a spray bar to remove protruding fibers, or punching, can be dispensed with.
[0137] In further embodiments, the height of the immersing portion can be at least twice as great as the material thickness of the at least one mold body in a wall or base section.
[0138] In further embodiments, the at least one support structure for the at least one mold body can be replaceably connected to a tool plate of the first tool component. Thus, not only the mold body but also the associated support structure can be replaced. This makes it possible to retrofit a tool plate of a tool component onto other mold bodies and support structures in order to carry out pre-pressing of other preforms, for example. The pre-pressing unit having the pre-pressing tool therefore does not have to be replaced as a whole, which considerably reduces the costs of providing a pre-pressing tool.
[0139] In some embodiments, the aforementioned problem is solved by a mold body for a pre-pressing tool for pressing three-dimensional preforms made of a fiber-containing material where the mold body includes a deformable material and is perforated at least in portions, and where the mold body has, with respect to a wall section and floor section, a greater material thickness in a connection section for a prepressing tool.
[0140] The connection section is the location at which the mold body is connected to a pre-pressing tool. High loads occur in the connection section when the tool closes, and therefore sufficient rigiditywhich also counteracts damageis provided by means of the stronger design. In addition, preforms can thus be pre-pressed in an edge section, as described below in exemplary embodiments. For this purpose, a sufficiently stable pressing surface, or a press-mating surface relative to a further tool, is provided by the stronger wall thickness and overall stronger design, which can be reinforced by at least one insert made of metal (e.g., connection unit).
[0141] In some embodiments, the aforementioned problem is solved by a mold body for a pre-pressing tool for pressing three-dimensional preforms made of a fiber-containing material where the mold body includes a deformable material and has, with respect to a wall section and floor section, a greater material thickness in a connection section for a pre-pressing tool, and where the mold body has an integrated connection unit in the connection section for a pre-pressing tool.
[0142] The connection section is the location at which the mold body is connected to a pre-pressing tool and can be connected to a tool part via the connection unit. The mold body can be connected or connectable, for example to a tool component of a prepressing tool, for example a tool plate, via the connection unit. An integrated design includes, for example, embodiments in which the connection unit is completely or almost completely surrounded by the flexible material of the mold body.
[0143] The ability to replace a mold body via the connection unit makes it possible to perform a tool change and provide maintenance without an entire tool plate having a plurality of mold bodies as a whole having to be replaced or serviced.
[0144] In various embodiments, the aforementioned problem is also solved by a prepressing tool having at least one mold body according to any of the preceding embodiments for pressing three-dimensional preforms made of a fiber-containing material, wherein the preforms have a moisture content of at least 50 wt. %, the tool having a first tool component having at least one support structure for a mold body made of a deformable material with a connection unit integrated in the connection section, and a second tool component having a corresponding cavity, wherein, in the closed state of the pre-pressing tool, a mold cavity for pressing preforms is formed between an outer surface of the mold body and an inner wall of the corresponding cavity, and wherein the at least one mold body is detachably connected to the first tool component via the at least one connection unit.
[0145] In this way, it is possible to replace specifically only mold bodies that are damaged or contaminated and have to be replaced or cleaned. It is therefore not necessary to replace, for example, a tool plate of the first tool component having a plurality of molding and support structures of a tool component.
[0146] As described above, it is possible to form products made of fiber containing materials wherein devices for pre-pressing that have elastic mold bodies provide sufficiently deforming of pre-pressed preforms to different degrees over the geometry of the preforms, such that pre-pressed preforms do not have different thicknesses and moisture content due to poor tool configuration. In addition, the teachings disclosed herein prevent preforms remaining adhering to the pre-pressing tool or suction tool and/or tearing. Furthermore, damage of preforms in a subsequent hot pressing process due to preforms with sections that are moist to different degrees and dry at different rates are prevented by the teachings disclosed herein.
[0147] Further high costs and efforts in the service lives of a pre-pressing tool are prevented, since the flexible material, which is connected to a corresponding tool plate and which has to be replaced over time does not result in replacing a whole tool plate which has multiple flexible mold bodies arranged thereon, even if only one flexible mold body is damaged, since the elastic bodies are each removeable connected to a tool plate. The costs for maintenance can thus be reduced by the teachings disclosed herein.
[0148] In addition, due to the configuration of the mold body, fraying of edges of pre-pressed preforms does not occur, so that removing (e.g. cutting) frays in a complex manner in downstream steps is not necessary and can be omitted. Thus, the manufacturing is less expensive and less complex saving costs and process time.
[0149]
[0150] Pulp refers to an aqueous solution containing fibers, wherein the fiber content of the aqueous solution can be in a range of 0.1 to 10 wt. %. In addition, additives such as starch, chemical additives, wax, etc. can be contained. The fibers can be, for example, natural fibers, such as cellulose fibers, or fibers from a fiber-containing original material (for example waste paper). A fiber treatment plant offers the possibility of preparing pulp in a large quantity and providing several fiber processing devices 1000.
[0151] The fiber processing device 1000 can be used to produce, for example, biodegradable cups 3000, 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.
[0152] The fiber processing device 1000 shown in
[0153] The control unit 310 is in bidirectional communication with an HMI panel 700 via a bus system or a data connection. The HMI (Human Machine Interface) panel 700 has a display which displays operating data and states of the fiber processing device 1000 for selectable components or the entire fiber processing device 1000. The display can be designed as a touch display so that adjustments can be made manually by an operator of the fiber processing device 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 fiber processing device 1000 can be influenced.
[0154] The fiber processing device 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 the figures, 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 arrangement of the corresponding stations of the fiber processing device 1000 may differ from the exemplary embodiment shown.
[0155] 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, e.g., cups 3000, as suction cavities 522. The suction cavities 522 can have, for example, a net-like surface on which fibers from the pulp are deposited during the suction. Behind the net-like surfaces, the cavities are connected to a suctioning device via channels in the suction tool 520. The suctioning device can be realized, for example, by a suction device 320 or a fan. Pulp can be suctioned in via the suctioning device when the suction tool 520 is located within the pulp tank 250 in such a way that the suction cavities 522 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 250 and the pulp, can be provided via the suction device 320. For this purpose, the fiber processing device 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 522. 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.
[0156] During 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 522 so that fibers are suctioned out of the pulp and are deposited for example on the network of suction cavities 522 in the suction tool 520.
[0157] Thereafter, the robot 500 lifts the suction tool 520 out of the pulp tank 250 and moves said tool together with the fibers that are adhering to the suction cavities 522 and still have a relatively high moisture content of, e.g., over 80 wt. % water, to the prepressing station 400 of the fiber processing device 1000, the negative pressure being maintained in the suction cavities 522 for the transfer. The pre-pressing station 400 has a pre-pressing tool with prepress molds 410. The prepress molds 410 can be formed, for example, as positives of the molded parts to be manufactured and have a corresponding size with regard to the shape of the molded parts in order to receive the fibers adhering in the suction cavities 522.
[0158] During the production of molded parts, the suction tool 520 is moved, with the fibers adhering in the suction cavities 522, to the pre-pressing station 400 in such a way that the fibers are pressed into or against the suction cavities 522. The fibers are pressed together in the suction cavities 522, 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 prepress molds 410 can be used, which are inflated, for example, by means of compressed air (process air), and in the process press the fibers against the wall of a suction cavity 522 in a further suction tool part. As a result of the inflation, both water is squeezed out, and the thickness of the sucked-in fiber layer is reduced.
[0159] During the pre-pressing, liquid or pulp can be extracted and returned via the suction tool 520 and/or via further openings in prepress molds 410 or pre-pressing tool parts (cavities).
[0160] After pre-pressing in the pre-pressing station 400, the preforms produced in this way are moved to a hot pressing station 600 on the suction tool 520 via the robot 500. For this purpose, the negative pressure 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 out of the hot pressing device 610. If the lower tool body 620 is in its extended position, the suction tool 520 is moved to the lower tool body 620 in such a way that the preforms can be placed on forming devices of the lower tool body 620. Subsequently, an overpressure is generated via the openings in the suction tool 520 so that the preforms are actively deposited by the suction cavities 522, or the suction is ended, so that the preforms remain on the forming devices of the lower tool body 620 due to gravity. By providing overpressure at the openings of the suction cavities 522, pre-pressed preforms resting/adhering in the suction cavities 522 can be released and dispensed.
[0161] Thereafter, the suction tool 520 is moved away via the robot 500 and the suction tool 520 is dipped into the pulp tank 250 in order to suction further fibers for the production of molded parts from fiber-containing material.
[0162] After the transfer of the preforms, the lower tool body 620 moves into the hot pressing station 600. In the hot pressing station 600, the preforms are pressed under heat and high pressure so as to produce finished molded parts, for which purpose an upper tool body 630 is brought onto the lower tool body 620 via a press. The upper tool body 630 has cavities corresponding to the forming devices. After the hot-pressing process, the lower tool body 620 and the upper tool body 630 are moved away from one another, and the upper tool body 630 is moved along the fiber processing device 1000 in the manufacturing direction; then, after the hot pressing, the molded parts are suctioned in via the upper tool body 630 and thus remain within the cavities. Thus, the manufactured molded parts are brought out of the hot pressing station 600 and deposited via the upper tool body 630 after traveling on a transport belt of a conveying device 800. After the molded parts are deposited, the suction via the upper tool body 630 is ended and the molded parts remain on the transport belt. The upper tool body 630 moves back into the hot-pressing station 600, and a further hot-pressing process can be carried out. Alternatively, the lower tool body 620 can be moved in an opposite direction prior to being extended to receive the preforms in order to move the manufactured products/molded parts out of the hot pressing device for further transport.
[0163] The fiber processing device 1000 further has a conveying device 800 with a transport belt. The manufactured molded parts 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 fiber processing device 1000. In further embodiments, after placing the molded parts 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.
[0164] The fiber processing device 1000 from
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[0166] The elastic material 422 is perforated and has a plurality of small openings, as indicated schematically in
[0167] The mold body 420 is arranged on the support structure 440. The inner surface of the elastic, elastic material 422 rests on the support structure 440 in the inactive state in which it is not subjected to pressure. The support structure 440 is a metal or a metal alloy. Preferably, the material of the support structure 440 has aluminum or consists essentially of aluminum. In further embodiments, other suitable materials can also be used for the support structure 440. In the exemplary embodiment shown, the support structure 440 is solid. In further embodiments, the interior of support structures 440 can be designed to be substantially hollow or have free spaces. This can save weight for a pre-pressing tool, for example.
[0168] The support structure 440 is connected to the tool body 402 of the pre-pressing tool via fastening means (e.g., screws), not shown. Support structures 440 can thus be replaced for a tool change or for cleaning purposes. In further embodiments, support structures 440 can also be fixedly connected to a tool body 402 or formed integrally with a tool body 402.
[0169] The support structure 440 has, at its lower floor section shown in
[0170] The channels 448 end at an outer surface of the support structure 440, at which the flexible material 422 of the mold body 420 rests in the inactive state. A feed channel 404 having a connector corresponding to the connector 444 is provided in the tool body 402. Compressed air can be introduced into the channel 446 and the channels 448 via the feed channel 404. The compressed air introduced then flows out of the support structure 440 and causes a deformation or inflation of the flexible material 422 of the mold body 420. Depending on thickness and the material used for the flexible material 422, the number and design of the channels 446, 448, the pressure and volume flow of the compressed air introduced, as well as other factors such as the perforation of the flexible material 422, the deformability of the mold body 420 can be influenced and controlled. In further embodiments, the surface of the support structure 440 and/or the inner side of the mold body can have structures (channels, grooves, etc.) which support the distribution over the entire surface of the mold body 420 when compressed air flows in. For example, channels 448 can have a greater diameter at their end in the outer surface of the support structure 440. Furthermore, openings in the outer surface of the support structure 440 connected with the channels 448 can be funnel-shaped so as to support air distribution over an area between the flexible material 422 and the outer surface of the support structure 440.
[0171] In the exemplary embodiment shown, the flexible material 422 of the mold body 420 has substantially the same wall or material thickness in a floor section 424 and in a wall section 426, so that deformation is uniform when compressed air is introduced into the space between the flexible material 422 and the surface of the support structure 440. It is thereby achieved that fiber-containing material of a preform is pressed uniformly, so that the fiber-containing material of the preform has a substantially uniform moisture content after the pre-pressing. As a result of the perforation of the flexible material 422, air is additionally guided through the fiber-containing material of a preform for dehumidification. The formation of the perforation and the compressed air introduced are to be coordinated in such a way that the deformation of the flexible material 422 takes place to a sufficient extent in order to provide the required pressing pressure that is required to squeeze out water from the relatively moist preforms.
[0172] The flexible material 422 has, in transitions from the floor section 424 to the wall sections 426 on the inner side, a radius R.sub.i which is greater than the radius R.sub.a of the flexible material 422 on the outer side. This supports uniform deformation of the flexible material 422 in the transitions from the floor section 424 to the edge sections 426. The uniform wall thickness of the flexible material 422 extends substantially over the mold body 420 surface (product section) that is in contact with the preform to be pressed during pre-pressing. The pre-pressing of an edge of preforms generally takes place in the pressing direction of the suction tool 520 to the pre-pressing tool, such an edge of a preform being supported in this case in the horizontal portion (shown in
[0173] To fasten the mold body 420 to the support structure 440, the mold body 420 has a ring 434 in the connection section 430. The ring 434 preferably is a metal (e.g., aluminum) or an alloy and, in the exemplary embodiment shown, has a plurality of preferably evenly distributed threaded holes via which the ring 434 is connected to the support structure 440 by means of screws 450. In further embodiments, a direct connection to a tool body 402 can also be realized via such a ring 434. The mold body 420 is thus replaceable so that, during a tool change or for cleaning and maintenance purposes, it is no longer necessary for an entire pre-pressing tool to be replaced, as is usually the case in the prior art.
[0174] In the exemplary embodiment shown, the support structure 440 has a substantially annular receptacle 442 in which the connection section 430 of the mold body 420 is received. The receptacle is adapted to the design of a connection section 430 and, in further embodiments, can also be designed to be angular or oval, depending on the design of the connection section 430 and the corresponding product geometry of a preform to be pre-pressed.
[0175] The flexible material 422 almost completely surrounds the ring 434 in the connection section 430. The ring 434 is accessible only in the section of the threaded holes. A ring 434 can be cast during the production of mold bodies 420.
[0176] The connection section 430 has a relatively large wall thickness at its outer edge 436 at a height H which is at least twice as large as the wall thickness in the product section. This increases the service life of the mold body 420. In addition, it provides a sufficient contact surface relative to the tool body 526 so that fibers that project over or out of the cavity in the interior of suction cavities 522 are pushed into the suction cavity 522 when the pre-pressing tool is closed or during the relative movement of the prepressing tool toward the suction tool 520. In this portion, the flexible material 422 serves as a wiper strip or block and prevents the formation of frayed edges in preforms and finished pressed or hot-pressed products. An additional station in fiber processing devices 1000 can thus be dispensed with.
[0177] During pre-pressing, the suction tool 520 with the suction cavities 522 is moved to the pre-pressing tool. Fibers from the pulp are deposited on nets or other similarly designed surfaces in the suction cavities 522.
[0178] During the relative movement of the suction tool 520 and the pre-pressing tool, the outer edge 436 of the connection section 430 first comes into contact with the inner wall surface of the tool body 526 (see
[0179] At the latest after reaching the position shown in
[0180]
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[0182] The channels 432 can extend through the ring 434, as shown schematically in
[0183]
[0184] The design of the prepress molds 410 makes it possible to considerably reduce the servicing and maintenance outlay and to provide preforms which have improved quality at faster pre-pressing times; the design of edges of the preforms can additionally be improved, so that additional processing stations and steps can be dispensed with.
LIST OF REFERENCE SIGNS
[0185] 1 pulp [0186] 11 environmentally-friendly, degradable fiber material [0187] 2 suction tool [0188] 21 suction head [0189] 21a suction head outside [0190] 21i suction head inside [0191] 21p end face of the suction head facing the pulp [0192] 21s suction head suction side [0193] 22 porous strainer of the suction head [0194] 22p pulp-facing side (pulp side) of the screen [0195] 22s side of the screen facing the suction side surface 23s [0196] 22w wave crests on the side 22s of the screen [0197] 22t wave troughs of the screen [0198] 23 suction channels in the suction head [0199] 23s suction-side surface of the suction head [0200] 24 collecting ring in the suction head [0201] 25 discharge channel for the liquid solution [0202] 26 base plate of the suction tool [0203] 27 gas line system in the base plate [0204] 27d compressed gas line in the gas line system [0205] 27h main gas line in the gas line system [0206] 27n secondary gas line in the gas line system [0207] 27v valves in the gas line system [0208] 28 reversible fastening means for the screen, e.g., clamping means [0209] 29 modules with suction heads [0210] 3 prepressing station [0211] 31 prepressing lower tool [0212] 31a pressing surface of the prepressing lower tool [0213] 33 cavity in prepressing lower tool [0214] 34 wall as the pressing surface of the prepressing lower tool [0215] 37 carrier plate [0216] 36 heating element of the carrier plate [0217] 4 movement unit [0218] 4a robotic arm that can move freely in space [0219] 4s interface [0220] 41 hot-pressing lower tool of the hot-pressing station [0221] 41a hot-pressing side of the hot-pressing lower tool, e.g., the outside [0222] 41k channels in the hot-pressing lower tool [0223] 42 hot-pressing upper tool of the hot-pressing station [0224] 42a hot-pressing side of the hot-pressing upper tool, e.g., the inside [0225] 43 heating cartridges [0226] 44 thermally insulating covering or material [0227] 45 carrier plates for the respective hot-pressing lower tool and hot-pressing [0228] upper tool designed as a multi-tool [0229] 46 bracket [0230] 47 expansion means [0231] 5 vacuum pump [0232] 6 reservoir of pulp [0233] 10 formed part made from environmentally-friendly, degradable fiber [0234] material [0235] 10a inner contour (inside) of the formed part [0236] 10i outer contour (outside) of the formed part [0237] 20 molding station [0238] 30 preforming station [0239] 35 pulp preparation and replenishment unit [0240] 40 hot-pressing station [0241] 40i inner tool [0242] 40a outer tool [0243] 50 control unit [0244] 60 coating unit [0245] 70 ejection unit [0246] 80 cutting unit [0247] 90 stacking unit [0248] 95 conveyor belt [0249] 100 fiber-forming system [0250] 200 process for the production of formed parts from environmentallyfriendly-degradable fiber material by means of a fiber-forming process in a fiber-forming system [0251] 210 molding of the formed part in a molding station [0252] 220 preforming of the formed part in a preforming station [0253] 230 final shaping of the formed part in a hot-pressing station [0254] 240 ejecting of the final-shaped formed part [0255] A-B cutting line in
[0303] At this point it should be explicitly pointed out that features of the solutions described above or in the claims and/or figures can also be combined if necessary in order to be able to implement or achieve the features, effects and advantages explained in a cumulative manner.
[0304] It goes without saying that the exemplary embodiment explained above is merely a first embodiment of the present disclosure. In this respect, the design of disclosed embodiments is not limited to this exemplary embodiment.