Method for manufacturing three-dimensional products from a fiber-containing material using at least one forming tool and forming tool

Abstract

A method for manufacturing three-dimensional products with at least one inclined product portion made of a fiber-containing material using at least one forming tool and a forming tool are described. Vibrations are introduced via a device and this results in an improved compression of fiber-containing material in the region of inclined portions.

Claims

1. A method for manufacturing three-dimensional products with at least one inclined product portion made of a fiber-containing material, using at least one forming tool, wherein the at least one forming tool has at least one first tool component with at least one cavity and at least one second tool component with at least one mold part corresponding to the at least one cavity, wherein the at least one mold part and the at least one cavity are movable relative to one another to form a mold cavity between corresponding surfaces of the at least one cavity and the at least one mold part, the method comprising: introducing a fiber-containing material into the at least one cavity of the at least one first tool component; closing the at least one forming tool by relative displacement of the at least one first tool component and the at least one second tool component; pressing the fiber-containing material within the mold cavity; and introducing vibrations by moving the at least one first tool component and/or the at least one second tool component relative to a pressing direction during the pressing.

2. The method according to claim 1, wherein the vibrations are introduced perpendicular to the pressing direction.

3. The method according to claim 1, wherein the vibrations are introduced into a product geometry in parallel or in an optimized direction of action.

4. The method according to claim 1, wherein the vibrations are introduced via the at least one mold part.

5. The method according to claim 1, wherein a frequency of the vibrations is modified during the pressing.

6. The method according to claim 1, wherein a duration of the vibrations and a duration of the pressing are different.

7. The method according to claim 1, wherein a pressure used for the pressing is modified during the pressing.

8. The method according to claim 1, wherein a frequency of the vibrations and/or a vibration duration are adapted to a pressure used for pressing.

9. The method according to claim 1, wherein the vibrations are introduced in a plane perpendicular to the pressing direction by a linear or rotating movement.

10. The method according to claim 1, wherein the vibrations are introduced according to a product geometry specification of a product to be manufactured.

11. A forming tool for manufacturing three-dimensional products with at least one inclined product portion from a fiber-containing material, comprising at least one first tool component with at least one cavity and at least one second tool component with at least one mold part corresponding to the at least one cavity, wherein the at least one mold part and the at least one cavity operable to be moved relative to one another to form a mold cavity between corresponding surfaces of the at least one cavity and the at least one mold part, and are operable to be pressed to press the fiber-containing material that is configured to be inserted into the mold cavity, the forming tool further comprising a device for introducing vibrations by moving the at least one first tool component and/or the at least one second tool component perpendicular to a pressing direction during the pressing.

Description

BRIEF DESCRIPTION OF THE FIGURES

In the Drawings:

[0028] FIG. 1 depicts a schematic illustration of a forming tool for manufacturing products from a fiber-containing material, according to some embodiments.

[0029] FIG. 2 depicts a schematic illustration of a forming tool for manufacturing products in an embodiment according to the prior art.

[0030] FIG. 3 depicts a schematic illustration of a forming tool after the insertion of a fiber material, with a device for introducing vibrations, according to some embodiments.

[0031] FIG. 4a), b) depict schematic illustrations of devices for introducing vibrations, according to some embodiments.

[0032] FIG. 5 depicts a schematic illustration of a molding plant for manufacturing products from a fiber material, according to some embodiments.

[0033] FIG. 6 depicts a method for manufacturing products from a fiber material, according to some embodiments.

DETAILED DESCRIPTION

[0034] 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.

[0035] The figures show exemplary embodiments of apparatuses for manufacturing products from a formable material, where the exemplary embodiments shown do not constitute a limitation with regard to further embodiments and modifications of the described embodiments.

[0036] FIG. 1 is a schematic illustration of a forming tool 10 for manufacturing products from a fiber material. The forming tool 10 can be part of a molding plant 100, as shown below with reference to FIG. 5. The forming tool 10 has a first tool component 12. The first tool component 12 includes a tool material for the manufacture of products from a fiber-containing material, and has corresponding properties, in particular with regard to strength and thermal conductivity. A second tool component 20 of the forming tool 10 can include the same material and have the same properties as the first tool component 12. Heating devices can be provided in the first tool component 12 and/or the second tool component 20, which bring the tool components 12, 20 to a temperature required for pressing fiber-containing material. Usually, the pressing of fiber-containing material takes place at temperatures in the range of 20 to 300 C., ideally from 100-200 C. In addition, the tool components 12, 20 are pressed under high pressure in the range of 100 N/cm.sup.2 to 5,000 N/cm.sup.2, ideally from 250 N/cm.sup.2 to 1,000 N/cm.sup.2 specific surface load. For this purpose, the forming tool 10 can be operatively connected to pressing devices, such as a toggle press. The toggle press can be part of a molding plant 100. The forming tool 10 can be interchangeably connected to the toggle press of the molding plant 100, so that different products can be manufactured using the molding plant 100 by changing the forming tool.

[0037] The first tool component 12 has at least one cavity 13, the surface 14 of which represents the external geometry of a product to be manufactured. The cavity 13 has a mold bottom 18 and slopes 16 extending laterally upwards from the mold bottom 18. The angle between the mold bottom 18 and the slopes 16 can, for example, be between 91 and 179. In most embodiments of products, such as cups, bowls, etc., a mold bottom 18 has an angle of 91 to 105 with respect to lateral slopes 16.

[0038] In further embodiments, the first tool component 12 can have a plurality of cavities 13 that extend flatly over the first tool component 12.

[0039] The second tool component 20 has at least one mold part 21 arranged corresponding to the at least one cavity 13 of the first tool component 12, which is immersed in the cavity 13 when the forming tool 10 is closed. The mold part 21 has a surface 22 that is formed corresponding to the surface 14 of the cavity 13. The surface 22 extends over a mold part bottom 26, which in the embodiment shown is aligned parallel to the mold bottom 18. In the closed state of the forming tool 10, slopes 24 of the mold part 21 are opposite the slopes 16. In the closed state of the forming tool 10, a mold cavity 11 is formed between the surface 14 of the at least one cavity 13 and the surface 22 of the mold part 21. In the mold cavity 11, fiber-containing material previously inserted into the cavity 13 is pressed with simultaneous pressure and temperature input. In this case, the fiber layer inserted into the cavity 13 can be compressed and thus pressed as soon as the forming tool 10 is closed. The final pressing is carried out when the forming tool 10 is completely closed.

[0040] The first tool component 12 and the second tool component 20 can each have a tool plate. In further embodiments, cavities 13 and mold parts 21 can be integrally installed on the mutually facing surfaces of the tool plates or can be detachably connected to the tool plates. In the case of a detachable connection, the cavities 13 and mold parts 21 can be fastened, for example, by means of screws. In such embodiments, at least one cavity 13 and/or mold part 21 can be replaced if, for example, a cavity 13/a mold part 21 is damaged, dirty or if replacement is necessary to manufacture other products.

[0041] The manufacture of products from a fiber-containing material takes place by inserting a suitable material, e.g. fiber material that includes exclusively natural fibers that have a relatively low moisture content. The water content can be, for example, 5 to 30 wt. %. Such fiber material can be introduced, for example, as a preformed preform made of a loose fiber composite (fluff pulp) or as individual fibers. In the following description, the fiber-containing material is generally referred to as fiber material. Such a fiber material can include different types of fibers.

[0042] FIG. 2 shows a schematic illustration of a forming tool 10 for manufacturing products in an embodiment according to the prior art, after a fiber material has been inserted and the forming tool 10 has been closed. For the pressing, a pressure is applied to the forming tool 10 as shown schematically by the arrow P. In the embodiment shown, pressure is applied only from above via the second tool component 20. In further embodiments of the forming tools 10 described herein, pressure can also be applied from below via the first tool component alternatively or additionally. Due to the applied pressure, the fiber material in the mold cavity 11 is pressed by the relative displacement of the mold part 21 and the cavity 13. The pressure required to manufacture a product leads to a desired pressing in the areas extending orthogonally to the applied pressure P, since the pressure can act on these areas over their entire surface. In these areas, a finished product has the required strength after pressing because the fibers in these areas have been sufficiently compressed. In FIG. 2, this is shown by the arrows in the region of the mold bottom 18 and the edge areas running parallel to it, which have a greater length or height than the small arrows in the region of the slopes 16 and 24. However, in the region of the slopes 160 and 24, the pressing force cannot develop the required effect via the applied pressure, which decreases considerably depending on the design of the slopes 16 and 24. For example, in the case of particularly steep slopes 16 and 24, the vertically acting pressing force can only achieve very poor compression of the fibers of the fiber material, so that the finished product does not have sufficient strength after pressing, especially in the region of slopes.

[0043] FIG. 3 shows a schematic illustration of a forming tool 10 after the insertion of a fiber material 40, with a device 30 for introducing vibrations according to the technical teaching disclosed herein, where a substantially uniform compression of inserted fiber material 40 is achieved over the entire surface, so that a finished product has a substantially uniform strength over the entire surface or product geometry.

[0044] The pressing and introduction of vibrations can be carried out substantially independently of the type of insertion of fiber material 40. For example, individual fibers and/or fiber bundles can be insertedwhere fiber bundles have a relatively small number of fibers that are attached to one another and thus form a bundle. In further embodiments, a fiber material 40 can be inserted into the cavity 13 as a preform or fiber mat made of loose fibers. For example, a preform can already substantially have the geometry of the product to be manufactured. In contrast, a fiber mat and/or a portion of a fiber mat has no preformed portions or formations and can be inserted into a cavity 13. The fiber mat can be designed like a fleece and can adhere to the surface 14 of the cavity 13 due to its own weight. Both a preform and a fiber mat can have a relatively loose composite of individual fibers and/or fiber bundles. The fibers/fiber bundles can be obtained in further versions in a comminuting device, such as a mill, from e.g. paper, cardboard, fleece, plant fibers, etc. The fibers and/or a fiber mat/preform can have a moisture content of 0-60 wt. % water. In still further embodiments, the fibers and/or the fiber mats/preform have a moisture content of 5-40 wt. % of water. In still further embodiments, the fibers and/or the fiber mats/preform have a moisture content of 7-30 wt. % of water.

[0045] After the comminution in a comminuting device, individual fibers are present, which are in a length spectrum of a few micrometers to, for example, 6 mm depending on the material used. Depending on their length, the fibers have different properties. Thus, in principle, higher strengths can be achieved in products with long fibers; however, long fibers exhibit poor formability. That is to say, it is generally possible to achieve only a non-uniform distribution on the product surface with long fibers (e.g., in the range of 4 to 6 mm). In contrast, short fibers (1-2 mm) have a lower strength with good formability. The density of a finished product is decisively influenced by fines (fiber parts) with a length of less than 1 mm, the proportion of which is basically higher in the case of short fibers. Thus, higher compressions can be achieved with shorter fibers and/or fiber fractions, where the mechanical properties and barrier properties of a product can be influenced accordingly. A very dense fiber layer can be produced, for example. Overall, the properties of the product to be produced can thus also be influenced by the length of the fibers.

[0046] The fiber material 40 can further have additives that affect the mechanical properties and the barrier action. Depending on the composition of the fiber material 40, products may be biodegradable, and can themselves be used again as starting material for manufacturing products, such as a cup-like product (see mold in FIG. 3) made from a fiber material, and can be composted because they can generally be completely decomposed and do not contain any questionable, environmentally hazardous substances.

[0047] A product can in particular be a three-dimensional product, such as, for example, a cup, lid, bowl, capsule, plate, and further molded and/or packaging parts (for example, as holding/support structures for electronic or other devices).

[0048] To introduce vibrations, the upper second tool component 20 is connected to a device 30. In further embodiments, the lower first tool component 12 can alternatively or additionally be connected to a device 30. In still further embodiments, at least one second device 30 that introduces vibrations can also be provided on a first tool component 12 and/or second tool component 20.

[0049] The at least one device 30 performs lateral movements L, thereby generating vibrations with a frequency in the range of 500 to 50,000 Hz, ideally 5,000 to 30,000 Hz. The frequency of the vibrations can be modified during a pressing process.

[0050] During the manufacture of products, a pressure P is exerted via the forming tool 10 in at least one time period, and at the same time vibrations are introduced via the at least one device 30 perpendicular to the pressing direction (shown schematically by arrow P), so that the fiber material 40 and/or the fibers are repeatedly squeezed between the surfaces 14, 22 of the cavity 13 and the mold part 21, in particular in the region of the slopes 16, 24. As a result, the fiber material 40 and/or the product in the region of the slopes 16, 24 is also compressed, where the fiber material 40 is thus compressed to substantially the same extent over the entire surface of the product to be manufactured, as shown schematically by the arrows on the fiber material 40 in FIG. 3. The arrows have the same length as in FIG. 2, which illustrates the pressing effect on the surface of the fiber material 40. As shown, in FIG. 3 the pressing effect is substantially the same, whereas in FIG. 2 the pressing effect is sufficiently large only in the region of the surfaces running orthogonal to the pressing direction and is too small in the region of the slopes 16, 24.

[0051] The at least one device 30 can, for example, be connected directly to the first tool component 12 and/or the second tool component 20. The at least one device 30 can, for example, be screwed to the first tool component 12 and/or the second tool component 20 or be an integral part thereof. The at least one device 30 can be arranged centrally with respect to at least one cavity 13 and/or a tool component 12, 20. A single device 30 can be provided for all cavities 13 and/or mold parts 21. In further embodiments, a separate device 30 can be provided for each cavity 13 and/or mold part 21.

[0052] In embodiments with cavities 13 and mold parts 21, which can be connected to tool plates via screws, for example, the connection between the tool plates and the cavities 13 and mold parts 21 fastened thereto is designed such that vibrations introduced via the at least one device 30 are transmitted without damping.

[0053] The at least one device 30 can be designed, for example, as a vibrator or as an ultrasonic sonotrode that is operated electrically. The power of such a device 30 is to be determined according to the weight of the forming tool 10 to be moved and the size of the mold cavity 11, as well as the fiber material and the applied pressing force P. For this purpose, the power with which the vibrations are introduced can be approximately determined in advance. Devices 30 or vibrators may include a motor having at least one shaft with an imbalance. The rotation generates centrifugal forces which, for the application described here, can be in the range between 1,000 N/cm.sup.2 and 10,000 N/cm.sup.2 specific surface pressure.

[0054] FIG. 4a), b) show schematic illustrations of devices 30 for introducing vibrations. Depending on the design of the at least one device 30 and its arrangement on a first tool component 12 and/or a second tool component 20, the vibrations can be introduced in a circular manner (FIG. 4a) or in a straight line (FIG. 4b). In the embodiments according to FIG. 4b), vibrations can be introduced both in one direction only and in directions orthogonal to each other.

[0055] The type of vibration introduction can depend significantly on the geometry of the product to be manufactured.

[0056] FIG. 5 shows a schematic illustration of a molding plant 100 for manufacturing products from a fiber material 40. The molding plant 100 has at least one controller 50, a feed device 60, and a forming tool 10. The forming tool 10 additionally has at least one device 30 via which vibrations are introduced into the forming tool 10. The controller 50 serves to control the processes and sequences of the molding plant 100, and is connected to the corresponding devices for this purpose. The controller 50 regulates the required energy and material conversion, and processes information and control commands for this purpose. The feed device 60 is used to feed fiber material between a first tool component 12 and a second tool component 20 of a forming tool 10, which has at least one cavity 13, and a corresponding mold part 21. In further embodiments, a molding plant 100 can have a forming tool 10 with a plurality of cavities 13 and corresponding mold parts 21.

[0057] The fiber material 40 can be inserted as a preform, as a fiber mat or as loose fiber material via the feed device 60 into at least one cavity 13 of at least one forming tool 10. In further embodiments, the fiber-containing material can be moistened in order to improve the bonding effect between the fibers of the fiber material 40 during the subsequent compressing. In yet further embodiments, a molding plant 100 can also have a preform station in which preforms are generated. For this purpose, in further embodiments, molding plants 100 can additionally or alternatively have a supply container for fiber material 40. Finally, a molding plant 100 can have an apparatus for removing and for further processing of molded products.

[0058] The manufactured product is then removed from the at least one cavity 13, and can be sent for further processing (coating, filling, sealing, printing, stacking, packaging, etc.).

[0059] FIG. 6 schematically shows a method 200 for manufacturing products from a fiber material. The manufacturing process can be carried out using a molding plant 100 as shown in FIG. 5. In further embodiments, the method 200 can be carried out using a forming tool 10 that has a different design than that shown in FIG. 3 and is part of a different design of a molding plant 100 than that shown in FIG. 5.

[0060] In an optional method step 210, fiber material 40 is provided. Depending on the type of material, the fiber material 40 can be provided in different ways. Thus, the provision can also include the production and/or processing of the fiber material 40.

[0061] In a subsequent method step 220, the fiber material 40 is inserted into at least one cavity 13 of at least one first tool component 12 of a forming tool 10. The fiber material 40 can be inserted as loose fibers/fiber bundles, as a fiber mat or as a preform. The insertion can be carried out using a feed device 60 of a molding plant 100.

[0062] After the introduction of the fiber material 40, the forming tool 10 is closed in a method step 230 by relative displacement of the at least one first tool component 12 and/or the at least one second tool component 20. During the closing, the fiber material 40 may be partially compressed.

[0063] In a method step 240, the fiber material 40 is pressed within the mold cavity 11 between the surface 14 of the cavity 13 and the surface 22 of the mold part 21. In a method step 250, vibrations are introduced by moving the at least one first tool component 12 and/or the at least one second tool component 20 perpendicular to the pressing direction during the pressing, where the vibrations are introduced by at least one device 30. Here, the fiber material 40 is pressed into the final product and the fibers are compressed within the mold cavity 11 in the region of the slopes 16, 24 by the vibrations.

[0064] During the pressing process, heat can be introduced and/or the fiber material 40 can be heated via the first tool component 12 and/or the second tool component 20, where the bonding of the fibers of the fiber material 40 is significantly influenced. For this purpose, the at least one cavity 13 and/or the at least one mold part 21 are preferably heated via heating elements arranged in a tool plate (e.g. electrically controllable heating cartridges), so that the surface 14 of the at least one cavity 13 and/or the surface 22 of the at least one mold part 21 have a surface temperature of 20 to 300 C., ideally 50 to 150 C.

[0065] The introduction of vibrations and the application of pressure during a pressing process can take place over different periods of time, and their intensity can be varied. In further embodiments, the time at which the pressing process begins and the time at which the introduction of vibrations begins may be different. For example, in other embodiments, vibrations can be introduced first and the pressing process can be started at a later time. In other embodiments, the pressing process begins before the introduction of vibrations. In other embodiments, the introduction of vibrations takes place simultaneously with the pressing process.

[0066] In still other embodiments, the pressing process or the introduction of vibrations can be terminated before the introduction of vibrations or the pressing process is terminated, respectively. In still other embodiments, the pressure during the pressing process and/or the duration and intensity of the vibrations during the pressing can be modified. For example, the introduction of vibrations can be increased with a continuously increasing pressure for pressing the fiber material 40, for which purpose the frequency of the vibrations is increased, for example. In further embodiments, for example, the centrifugal force of an excenter can be achieved by changing the speed of a shaft connected to the excenter. In other embodiments, however, both the pressing force and the intensity of the vibrations can decrease continuously (e.g. reduction of the frequency; reduction of the speed of an unbalanced shaft).

[0067] Further manufacturing and processing steps can be carried out in optionally provided process steps 260. These include, for example, coating, filling, closing, stacking, printing, packaging, quality control, etc.

[0068] The above sequence can then be repeated for at least one new product.

[0069] Advantageously, by introducing vibrations, the surface pressure on the entire surface of a forming tool 10 or the geometry of a product to be manufactured, even in the region of slopes 16, 24, can be substantially the same as in surfaces of the forming tool 10 aligned parallel to the pressing direction (e.g. mold bottom 18; mold part bottom 26), where the pressing direction does not run parallel to the slopes 16, 24. This achieves uniform strength across the entire surface of a product without the known disadvantages of the prior art. In particular, flexible tool components, which have disadvantages with regard to heat transfer, can be dispensed with. Furthermore, even with thin-walled products, consistent strength and identical properties can be achieved across the entire surface of a product.

LIST OF REFERENCE SIGNS

[0070] 10 forming tool [0071] 11 mold cavity [0072] 12 first tool component [0073] 13 cavity [0074] 14 surface [0075] 16 slope [0076] 18 mold bottom [0077] 20 second tool component [0078] 21 mold part [0079] 22 surface [0080] 24 slope [0081] 26 mold part bottom [0082] 30 device [0083] 40 fiber material [0084] 50 controller [0085] 60 feed device [0086] 100 molding plant [0087] 200 method [0088] 210-260 method step