Molding tool, molding machine and method for molding three-dimensional articles

Description

Technical field

[0001] The present invention relates to the forming of sheet-like material sheets into three-dimensional articles. In particular, the invention relates to a forming tool and the use of such a forming tool for forming a sheet of material into at least one three-dimensional article. Furthermore, the invention encompasses a method for producing at least one three-dimensional article from a sheet-like material sheet. State of the art

[0002] Containers, cups, or capsules made of plastic materials such as polyethylene terephthalate (PET), polystyrene (PS), or polypropylene (PP) are used for large-scale portioning and packaging of food. Injection molding or a forming process such as thermoforming can be used to manufacture such items.

[0003] During thermoforming, a thermoplastic film is placed between a lower tool part and an upper tool part of the thermoforming tool used. The opened thermoforming tool is then closed by moving the two tool parts towards each other. The film placed between the two tool parts is pre-stretched into at least one mold cavity of a mold accommodated in the lower tool part or upper tool part using compressed air and / or at least one pre-stretcher. With the help of compressed air and / or negative pressure, the pre-stretched film can be completely formed in the at least one cavity, with the side wall of the mold cavity and the mold base closing the cavity defining the shape of the article to be formed. The thermoforming tool is then opened, i.e. the two tool parts are moved away from each other again, and the formed article can be removed from the thermoforming tool.

[0004] In multiple-cavity tools, the mold has a plurality of mold cavities. This allows a plurality of articles to be molded simultaneously in one molding cycle. Such molds and molding methods for forming thermoplastic films or plastic sheets into three-dimensional articles, in particular containers, cups, or capsules, are known, for example, from the publications EP 1 163 996 B1, DE 20 2018 106 461 U1, and US Pat. No. 6,440,354 B1. Furthermore, US Pat. No. 5,759,594 A discloses a mold designed for forming fiber-reinforced plastic films. The mold comprises a lower mold part and an upper mold part, as well as a cutting device with a cutting blade arranged circumferentially on the lower mold part. The cutting blade can be moved with the aid of an actuator to cut or incise the material sheet.

[0005] US 2007 / 0 257 397 A1 also discloses a thermoforming tool with a movable cutting device designed to cut off excess material during the forming of a material sheet into three-dimensional articles. Forming tools with cutting elements for cutting or incising a material sheet to be formed are also known from EP 2 408 607 B1, US 2009 / 0096127 A1, and EP 2 945 878 B1. In the publications cited here, the cutting of a material sheet takes place with the forming tool closed.

[0006] The advantage of thermoforming processes is that items can be produced in large quantities, in good quality and at low cost. However, the disadvantage is that improperly disposed of plastic items pollute the environment because they are not biodegradable. Due to the steady increase in plastic waste, the need to produce food portion containers from biodegradable material has grown. In recent years, there have been encouraging approaches to producing containers from natural fibers, particularly cellulose. For example, WO 2017 / 160218 A1 describes a technique in which cellulose fibers are processed into flat sheets and then formed into three-dimensional articles using a molding press. Forming pressures in the range of 1 MPa to 100 MPa and temperatures in the range of 100 °C to 300 °C are required to form cellulose sheets into three-dimensional articles of the desired wall thickness.

[0007] EP 2 408 607 B1, US 2019 / 070819 A1, US 5 759 594 A, US 2009 / 096127 A1 and EP 2 945 878 B1 disclose molding tools according to the preamble of claim 1.

[0008] However, since natural fiber sheets do not possess the elastic properties of thermoplastic materials, producing containers in large quantities and with consistent quality remains a challenge. Even chemical treatment of natural fiber sheets with additives cannot achieve the elastic properties of thermoplastic plastic films. As a result, uncontrolled cracking can repeatedly occur in the natural fiber sheets during the forming process.

[0009] It is therefore an object of the present invention to provide a forming technique which further improves the state of the art and in particular eliminates the problems described above in the forming of material sheets made of natural fibers. Brief outline

[0010] To achieve at least the above-mentioned object, according to a first aspect, a forming tool for forming a material sheet into at least one three-dimensional article is provided, wherein the forming tool is designed to selectively assume an open and a closed state, wherein the forming tool comprises: a first tool part and a second tool part interacting with the first tool part, wherein in the closed state of the forming tool, the two tool parts are moved towards one another, and wherein in the open state of the forming tool, the two tool parts are moved away from one another; a first mold half arranged in the first tool part and a second mold half arranged in the second tool part, wherein the two mold halves are designed to form the material sheet arranged between the two tool parts into at least one three-dimensional article when the two tool parts are moved towards one another;and a cutting device comprising at least one cutting element and at least one actuating device coupled to the at least one cutting element, wherein the at least one actuating device is designed to disengage the at least one cutting element in the direction of the material sheet arranged between the two tool parts in order to cut the material sheet, wherein the forming tool is in the open state or in a partially open state;

[0011] Cutting may, in particular, comprise pre-cutting the material sheet. However, cutting may also comprise complete cutting (finish cutting) of the material sheet (e.g., to separate the formed articles from the residual skeleton of the material sheet). In particular, cutting may also comprise pre-cutting and finish cutting of the material sheet, both to pre-cut the material sheet for forming the articles and to completely separate the formed article from the material sheet (or the residual skeleton of the material sheet).

[0012] The first tool part can be designed as the upper tool part or as the lower tool part of the mold. Accordingly, the second tool part can be designed as the lower tool part or as the upper tool part of the mold. The first mold half can comprise a positive mold (male mold) or a negative mold (female mold). Accordingly, the second mold half can comprise a negative mold (female mold) or positive mold (male mold) corresponding to the first mold half. The positive mold can comprise at least one forming punch. The negative mold can comprise at least one mold cavity corresponding to the at least one forming punch. Regardless of the specific implementation, the two mold halves are designed to cooperate when the mold is closed in such a way that they deform the material sheet arranged therebetween into the at least one desired three-dimensional article.

[0013] The terms "open state" and "closed state" are further defined below. In the "open state," the two tool parts (and thus also the two mold halves) of the mold are moved away from each other. In this state, a sheet of material can be placed between the two tool parts or mold halves (for example, using a conveyor device). Furthermore, in the open state, an article formed in the mold can be removed from the mold (for example, using a removal device). In the "closed state," however, both tool parts (and thus also the mold halves arranged in the two tool parts) are moved toward each other. In the closed state, the two mold halves assume their final forming position, in which the article takes on its final shape.

[0014] A "partially open state" refers to a state of the mold in which the two mold parts (and their mold halves) are at least far enough apart that the material sheet arranged between them is not yet (significantly) deformed or reshaped by the two mold halves. The at least one cutting element can be disengaged until it comes into contact with at least one opposing counter-cutting element of the mold and cuts (or punches) the material sheet arranged between them. Alternatively, the at least one cutting element can be disengaged to a predetermined position.Subsequently, the tool part opposite the at least one cutting element can be moved with the at least one counter-cutting element toward the at least one cutting element until the at least one counter-cutting element comes into contact with the at least one cutting element and cuts (or punches) the material sheet arranged between the counter-cutting element and the cutting element. The predetermined disengagement position can be directly below or above the material sheet. By disengaging the at least one cutting element, it is possible to (locally) cut (pre-cut) the material sheet before the material sheet is (significantly) formed.

[0015] The at least one actuating device can further be configured to re-engage the at least one cutting element after cutting (pre-cutting) the material sheet. After the at least one cutting element has been engaged, the two tool parts and their mold halves can continue to move toward each other, thereby forming the material sheet into the at least one article.

[0016] The at least one cutting element can be designed and arranged in the forming tool such that, in the disengaged position, it at least partially pre-cuts or cuts the material sheet at the outer edge of the article to be formed or in the vicinity of the outer edge of the article to be formed. The partial pre-cutting can comprise a locally limited cutting of the material sheet in regions in which high deformation forces (tensile stresses) occur during the forming process (for example, at the outer edges of the article). Alternatively, it is also conceivable for the at least one article to be completely pre-cut in the circumferential direction. In this case, the pre-cut corresponds to a final cut in which the article to be formed is separated from the remaining material sheet. In both cases, the cut with the at least one cutting element is carried out substantially before the material sheet is formed into the at least one three-dimensional article.The pre-cutting of the material sheet before forming, as described here, effectively "flexibilizes" the material sheet to be formed. The material sheet can be formed more easily and lower deformation forces act on the material sheet, thus eliminating or at least significantly reducing the occurrence of uncontrolled cracks in the material sheet.

[0017] Alternatively, it is also conceivable that the at least one article, after its forming, is cut (finish-cut) from the material sheet using the at least one retractable cutting element. The cutting (finish-cut) can be performed with the forming tool partially or fully open by retracting the corresponding cutting element.

[0018] The at least one cutting element can be arranged in the first tool part and / or the second tool part. In particular, the at least one cutting element can be arranged near the first mold half and / or the second mold half. The at least one cutting element is thus part of the mold, thus realizing a particularly compact design.

[0019] The at least one actuating device, which is provided for engaging and disengaging the at least one cutting element, can also be arranged in the first tool part and / or the second tool part. The at least one actuating device can thus also be a component of the molding tool. In this way, a particularly compact design is realized, so that the molding tool can be mounted in a conventional molding machine / molding press.

[0020] The cutting device can further comprise a counter-cutting element that interacts with the at least one cutting element. This counter-cutting element can be arranged in the tool part opposite the at least one cutting element. If the cutting element is arranged in the first tool part, the counter-cutting element can be arranged in the opposite second tool part. If, however, the at least one cutting element is arranged in the second tool part, the counter-cutting element can be arranged in the first tool part.

[0021] The at least one retractable cutting element may comprise at least one cutting blade. The cutting blade may, for example, comprise a wedge-shaped cutting blade or another type of blade. The counter-cutting element may comprise a cutting support that interacts with the at least one cutting blade.

[0022] The at least one actuating device can comprise a disengaging and re-engaging mechanism. This is provided to disengage and re-engage the at least one cutting element as needed. For this purpose, the disengaging and re-engaging mechanism can be mechanically coupled to the at least one cutting element. For the coupling, for example, a carrier element or a carrier plate can be provided, which receives the at least one cutting element on one side and is in contact with the engaging and disengaging mechanism on the opposite side. The engaging and disengaging mechanism can be implemented in the form of a pneumatically or hydraulically actuated piston-cylinder device. Alternatively, it is also conceivable for the engaging and disengaging mechanism to be implemented in the form of an electromechanical actuating device.

[0023] Furthermore, the at least one actuating device can comprise a support mechanism. The support mechanism can be provided to support the at least one cutting element during the cutting process. The support mechanism serves to relieve the load on the disengaging and engaging mechanism, since during cutting (punching) considerable compressive forces act on the at least one cutting element and the disengaging and engaging mechanism coupled to the at least one cutting element.

[0024] In addition to the above-described retractable cutting element, the forming tool may comprise at least one cutting line arranged in the first and / or second tool part. The at least one cutting line arranged in the first and / or second tool part may be designed to separate (completely cut out) the at least one formed article from the material sheet after the forming process. The at least one cutting line may be in the form of a strip steel line.

[0025] If the complete cutting out of the at least one formed article from the material sheet is carried out by the above-described cutting device with the at least one disengageable cutting element, the cutting line / cutting edge additionally arranged on the first and / or second tool part can also be omitted.

[0026] The material sheet to be formed can consist predominantly of fibers, particularly natural fibers. The natural fibers can be plant fibers or fibers of animal origin. In particular, the fibers can be cellulose fibers.

[0027] According to a further aspect of the invention, a use of the above-mentioned molding tool for producing at least one three-dimensional article from a sheet-like material sheet is provided. The material sheet may consist, in particular, of natural fibers. According to one implementation, the natural fibers may comprise cellulose. The article may, for example, be a container, a cup, a capsule, a lid, or another three-dimensional article.

[0028] According to a further aspect of the invention, a molding machine, in particular a molding press, is provided for producing at least one article from a flat sheet of material. The molding machine comprises the molding tool described above, having a first molding tool part and a second molding tool part; an upper table for receiving the first molding tool part, and a lower table for receiving the second molding tool part, wherein the upper table and / or the lower table is / are movably mounted.

[0029] The molding machine can be designed to apply a predetermined molding pressure to the molding tool. Furthermore, the molding machine can comprise a conveyor device configured to (intermittently) feed the material sheet to the molding tool.

[0030] According to a further aspect of the invention, a method is provided for producing at least one three-dimensional article, in particular a cup, from a sheet-like material sheet, the method comprising the following steps: providing the above-mentioned molding tool; arranging the sheet-like material sheet between the two mold halves of the molding tool; disengaging the at least one cutting element of the molding tool in the direction of the material sheet arranged between the two tool parts; cutting the material sheet with the aid of the at least one cutting element when the molding tool is open or at least partially open; engaging the at least one cutting element after the material sheet has been cut; and subsequently closing the molding tool and forming the material sheet into at least one three-dimensional article.

[0031] The material sheet can in particular be a flat material sheet made of natural fibers, in particular cellulose fibers.

[0032] The step of placing the sheet-like material between the two mold halves can be performed whenever the mold is in the open state, i.e., when the two mold parts with the corresponding mold halves are moved away from each other, as described above. The sheet-like material can be fed (intermittently) to the mold with the aid of a conveyor and thus placed between the two mold parts.

[0033] The step of disengaging the at least one cutting element may comprise positioning the at least one cutting element directly below or above the material sheet. "Directly below or above the material sheet" may mean a position in which the at least one cutting element, in the disengaged state, is positioned in the immediate vicinity below or above the material sheet arranged between the two tool parts, without touching it. Furthermore, the subsequent step of cutting with the aid of the at least one cutting element may comprise moving the tool part opposite the at least one cutting element in the direction of the disengaged cutting element until the at least one counter-cutting element (or the cutting support of the counter-cutting element) comes into contact with the at least one cutting element.By contacting the cutting element and the cutting support of the counter-cutting element, the material sheet in between is severed in the area of ​​the cutting element.

[0034] The cutting step using the disengageable cutting element can thus include pre-cutting the material sheet at predetermined positions to prevent uncontrolled cracking during the subsequent forming process. The pre-cutting of the material sheet can be performed in localized areas of the material sheet that are in the immediate vicinity of the cup rim. The final cut to separate the formed article from the material sheet can be performed in a subsequent cutting step with a cutting line different from that of the disengageable cutting element when the tool is closed (so-called final cut).

[0035] The step of engaging the at least one disengaged cutting element can comprise a slight movement of the tool part with the counter-cutting element away from the tool part with the at least one cutting element in order to release the at least one cutting element for engagement. Alternatively, it is also conceivable for the at least one cutting element to be engaged without the tool part opposite the at least one cutting element moving away from it. After engagement or even during engagement, the two tool parts can be moved toward each other to be transferred into the final forming position.

[0036] According to a further aspect of the invention, a method is provided for producing at least one three-dimensional article, in particular a cup, from a sheet-like material sheet, the method comprising the following steps: providing the above-mentioned forming tool; arranging the sheet-like material sheet between the two mold halves of the forming tool; closing the forming tool and forming the material sheet into at least one three-dimensional article; disengaging the at least one cutting element of the forming tool; and cutting out, with the aid of the at least one disengaged cutting element, the at least one three-dimensional article from the material sheet.

[0037] The at least one cutting element of the forming tool can be disengaged when the forming tool is open or at least partially open.

[0038] The step of cutting out the at least one three-dimensional article also takes place with the mold open or at least partially open. By moving at least one of the two mold parts, the at least one disengaged cutting element can be moved against the counter-cutting element arranged opposite the at least one cutting element, whereby the material sheet with the formed article(s) arranged between the at least one disengaged cutting element and counter-cutting element is cut. Alternatively, the at least one cutting element can be disengaged until it comes into contact with the opposite counter-cutting element, whereby the material sheet with the formed article(s) arranged therebetween is cut.

[0039] The disengaged cutting element can be reengaged after cutting out the at least one three-dimensional article. Short character description

[0040] Further details and advantages of the invention will be further described with reference to the embodiments shown in conjunction with the figures. They show: Figure 1 shows a representation of a forming tool according to the present invention; Figure 2 shows a flowchart illustrating a method for forming flat material sheets according to the present invention; Figures 3a to 3j show representations of a further forming tool for forming a material sheet; and Figure 4 shows representations of a further forming tool for forming a material sheet. Detailed description

[0041] Figure 1 shows a molding tool 100 according to the invention, which is installed in a molding machine 1. The molding machine 1 is only schematically indicated by an upper table 2 and a lower table 3.

[0042] The mold 100 comprises a first tool part 120 and a second tool part 140. In the Figure 1 In the implementation shown, the first tool part 120 is designed as the upper tool part and the second tool part 140 as the lower tool part of the molding tool 100. The first tool part 120 is mounted on the upper table 2 and the second tool part 140 on the lower table 3 of the molding machine 1. As can also be seen from the Figure 1As indicated by arrows 20 and 22, at least one of the two tables 2 and 3 can be movable in the vertical direction (i.e., perpendicular to the planes of the two tables 2, 3). Thus, the two tool parts 120, 140 are movably mounted in the molding machine 1. They can be moved toward each other (shown by arrows 20 on the left) or away from each other again (shown by arrows 22 on the right). Accordingly, the molding tool 100 can assume a closed state (position) when the two tool parts 120, 140 are (fully) moved toward each other, or an open state (position) when the two tool parts 120, 140 are (fully) moved away from each other. In the Figure 1 In the illustration shown, the forming tool 100 is in the open state, ie the two tool parts 120, 140 are moved away from each other.

[0043] The first tool part 120 comprises a first mold half 130 (hereinafter also referred to as the upper mold half 130), which is designed as a negative mold (male mold) and has at least one cavity 132. The first mold half 130 is mounted on a first support device 122 of the first tool part 120. The second tool part 140 comprises a second mold half 134 corresponding to the first mold half 130, which is designed as a positive mold (male mold) and has at least one punch 136 corresponding to the cavity 132. The second mold half 134 is mounted on a second support device 142 of the second tool part 140. The specific configuration of the two mold halves 130, 134 is not important for the present invention. According to an alternative implementation, it is also conceivable for the first mold half 130 to be designed as a male mold and the second mold half 134 to be designed as a female mold.What is crucial is that the two mold halves 130, 134 interact in the closed state in such a way that they transform a material sheet 10 stored between the two mold halves 130, 134 into the at least one desired article.

[0044] The material sheet 10 to be formed can be made of natural fibers or another recyclable material. Plant fibers or fibers of animal origin can be used as natural fibers. In particular, the material sheet can contain cellulose fibers.

[0045] As further stated in the Figure 1 As indicated, the material sheet 10 to be formed can be fed (intermittently) to the forming tool 100 by means of a conveyor device 4. The conveyor device 4 can be part of the forming machine 1 and is in Figure 1 only schematically indicated by two rollers (see rollers 4). The direction of transport is indicated by arrows 12.

[0046] The forming tool 100 further comprises a cutting device 180. The cutting device 180 comprises at least one cutting element 182 and at least one actuating device 184 coupled to the at least one cutting element 182. The at least one actuating device 184 is provided to selectively disengage or reengage the at least one cutting element 182 in the direction of the material sheet 10 to be formed. The disengagement position 189 of the at least one cutting element 182 is shown on the right in the figure. On the left in the Figure 1The at least one cutting element 182 can be seen in its engaged position. By disengaging the at least one cutting element 182, it is possible to cut the material sheet 10, in particular to pre-cut it, even before the material sheet 10 has undergone any significant deformation. It is also conceivable to design the at least one cutting element 182 such that, with the aid of the at least one disengageable cutting element 182, the at least one article formed in the material sheet 10 can be completely cut out. This cutting process or cutting-out process will be described in more detail below in connection with the following figures.

[0047] The at least one cutting element 182 and the at least one actuating device 184 are arranged in the lower tool part 140. However, an arrangement in the upper tool part 120 is also conceivable. Regardless of the arrangement in the lower tool part 140 or upper tool part 120, the at least one cutting element 182 is arranged in the vicinity of the second mold half 134 or first mold half 130 such that the at least one cutting element 182, in the disengaged position, cuts, in particular pre-cuts, the material sheet 10 in the vicinity of the article 10 to be formed. In particular, the at least one cutting element 182 can be aligned with respect to the mold halves 130, 134 such that it pre-cuts the material sheet 10 locally in those areas (positions) where strong deformations and thus strong deformation forces (tensile forces) occur during the subsequent forming process.Such areas of strong deformation and thus high deformation forces include, for example, the corners of a product. By locally pre-cutting the material sheet in the corner area, the material sheet 10 can be locally "flexibilized," which significantly reduces the tensile forces occurring during forming and thus prevents uncontrolled cracking in the material sheet 10.

[0048] In addition to the local cutting or pre-cutting described here, it is also conceivable that the at least one cutting element 182 is designed and arranged such that it completely cuts the material sheet 10 along or near the outer peripheral edge of the article to be formed. In this implementation, the cut is a final cut, in which the material sheet region to be formed or formed into the article is separated from the remaining material sheet before / after it is / has been formed. Accordingly, the at least one cutting element 182 is designed and arranged on the lower tool part 140 or upper tool part 120 such that it (completely) surrounds the corresponding mold halves 130 and 134, respectively, along their outer circumference.

[0049] The cutting device 180 may further comprise at least one counter-cutting element 186. The at least one counter-cutting element 186 is arranged opposite the at least one cutting element 182. In the Figure 1 In the implementation shown, the at least one counter-cutting element 186 is arranged on the upper tool part 120. In contrast to the Figure 1 In the implementation shown, the at least one cutting element 182 is arranged in the upper tool part 120, the counter-cutting element 186 is arranged opposite on the lower tool part 140. The at least one counter-cutting element 186 comprises at least one counter-cutting support 187, against which the at least one cutting element 182 is pressed when cutting the material sheet.

[0050] Figure 1For the sake of simplicity, the molding tool 100 is shown with only one mold. It is understood that the molding tool 100 described here can also be a multiple-use tool, comprising a plurality of (identical or different) molds with corresponding mold cavities 132 and corresponding mold punches 136. These are arranged next to one another (for example in matrix form) in the upper tool part 120 and the lower tool part 140. In such a multiple-use tool, at least one cutting element 182 is provided for each mold. The cutting elements 182 assigned to the respective molds can be jointly actuated (i.e., disengaged and re-engaged) by a common actuating device. Alternatively, it is also conceivable that a separate actuating device 184 is provided for each mold to actuate the cutting element 182 belonging to each mold.

[0051] A function of the associated with Figure 1The process of manufacturing the described mold 100 is described in the flow chart in Figure 2 described further. Figure 2 describes a method 200 for producing at least one article, wherein the method 200 is carried out using the tool 100.

[0052] In a first step S201 of method 200, the molding tool 100 described above is provided. Providing the molding tool 100 may include mounting the molding tool 100 in a molding machine 1 (molding press). The two tool parts 120, 140 are mounted displaceably relative to one another in the molding machine 1 of the molding tool 100. "Displaceably mounted" means that at least one of the two tool parts 120, 140, with its mold halves 130, 134, is movable, so that the molding tool 100 can transition cyclically into an open state and a closed state.

[0053] In the open state of the mold 100 (i.e., when the two tool parts 120, 140 are moved apart), in a next step S202, a flat material sheet 10 is arranged between the two tool parts 120, 140 (or their mold halves 130, 140). The arrangement can be carried out with the aid of a conveyor device 4, as described in connection with the Figure 1 briefly described. Figure 1 shows the forming tool 100 in the open state and the arrangement of the material sheet 10 to be formed between the two tool parts 120, 140.

[0054] In a subsequent step S203, with the forming tool 100 open or still partially open, the at least one cutting element 182 arranged in the forming tool 100 is disengaged in the direction of the material sheet 10 arranged between the two tool parts 120, 140. The disengagement takes place with the aid of the Figure 1described actuating device 184 is essentially perpendicular to the feed direction of the material sheet 10. The feed direction is in the Figure 1 indicated by the arrows 12.

[0055] In the subsequent step S204, the material sheet 10 is cut with the aid of the at least one cutting element 182. The cutting step occurs when the at least one cutting element 182 is brought into contact with the at least one opposing counter-cutting element 186 (or its counter-cutting support 187). This can be done, for example, by disengaging the at least one cutting element 182 until it comes into contact with the at least one counter-cutting element 186 (or the counter-cutting support 187 of the counter-cutting element 186). Alternatively, the at least one cutting element 182 can be extended to a predetermined position (just) below or above the material sheet 10 (see position 189 in Figure 1) and then the lower tool part 140 in the direction of the upper tool part 120 or the upper tool part 120 in the direction of the lower tool part 140 or both tool parts 120, 140 are moved towards each other until the at least one cutting element 182 comes into contact with the corresponding counter-cutting element 186 (or its cutting support 187). If the at least one cutting element 182 comes into contact with the opposite counter-cutting element 186, the material sheet 10 arranged therebetween is cut or punched at the corresponding positions. Since the at least one cutting element 182 is disengaged by means of the at least one actuating device 184, this cut takes place with the forming tool 100 open or at least still partially open.A partially opened mold 100 means a state in which the two tool halves 120, 140 are at least far enough apart that they do not significantly deform or reshape the material sheet 10 lying between them.

[0056] In the subsequent step S205, after cutting (pre-cutting) the material sheet 10 with the aid of the at least one cutting element 182, the at least one cutting element 182 is re-engaged. The engagement step S205 is carried out with the aid of the at least one actuating device 184, which returns from its disengaged state to the engaged state (basic state).

[0057] In the subsequent step S206, the mold 100 is closed, i.e., the two mold parts 120, 140 are moved completely towards each other. As a result, the material sheet 10 arranged between the two mold halves 130, 134 is formed into a three-dimensional article. During forming, the material sheet to be formed can be heated to a desired forming temperature. Typical forming temperatures for forming material sheets made of natural fibers are in the range from 50 °C to 300 °C. The desired forming temperature can be generated by a heating device arranged in the mold 100. Furthermore, a desired forming pressure can be exerted on the mold 100 by means of the forming machine 1. Typical forming pressures for material sheets made of natural fibers are in the range from 1 MPa to 100 MPa. The specific forming temperature and forming pressure are individually adjusted depending on the material of the material sheet 10 to be formed and the geometry of the article to be produced.The produced item can be a container, cup or capsule for portioning food.

[0058] To separate the produced article from the material sheet 10, a cutting line or cutting edge can additionally be integrated into the forming tool 100. This cutting line or cutting edge is arranged and configured in the upper tool part 120 or lower tool part 140 such that, when the forming tool 100 is closed, it cuts or punches the material sheet 10 along the outer edge of the article. Alternatively, it is also conceivable that the material sheet 10 with the at least one formed article is fed to a downstream punching station, which punches out the at least one formed article.

[0059] In connection with the Figures 3a to 3j a molding tool 100a is described which is a further development of the molding tool 100a described in connection with Figure 1 discussed mold 100. In the Figures 3a to 3jFeatures and tool elements that are similar or identical to the mold 100 in the Figure 1 are provided with the same reference numerals.

[0060] Figure 3a shows the molding tool 100a in the open state. The molding tool 100a comprises a first (upper) tool part 120, which comprises a first carrier device 122 and a first (upper) mold half 130 arranged on the carrier device 122. The first mold half 130 is in turn designed as a negative mold (matrix) with at least one cavity 132. The first carrier device 122 can be designed in the form of a carrier plate. The upper tool part 120 further comprises at least one counter-cutting element 186 with a cutting support 187, as described in connection with the Figure 1discussed. Furthermore, the upper tool part 120 comprises a cutting line (or cutting edge) 150 surrounding the first mold half 130 in the circumferential direction, which is provided for the final cutting of a formed article and in connection with Figure 3i described further below. Furthermore, the forming tool 100a can have at least one upper stop element 162 for the preliminary cut described further below and one upper stop element 164 for the final cut.

[0061] The mold 100 according to Figure 3afurther comprises a second (lower) tool part 140, which comprises a second carrier device 142 and a second (lower) mold half 134 arranged on the carrier device 142. The second mold half 134 is in turn designed as a positive mold (male mold) with at least one punch 136 cooperating with the cavity 134. The second carrier device 142 can in turn be designed in the form of a carrier plate. The lower tool part 140 further comprises a cutting device 180 with at least one cutting element 182 and at least one actuating device 184 coupled to the at least one cutting element 182. In the Figures 3a to 3jTwo cutting elements 182 (and two actuating devices 184) can be seen flanking the lower mold half 134. It is understood that, deviating from this, the molding tool 100a can also have three or more cutting elements 182 flanking the lower mold half 134. The at least one actuating device 184 can be designed as a pneumatic, hydraulic, or electromechanical actuating device. The at least one cutting element 182 can be implemented as a cutting blade, preferably as a wedge blade.

[0062] Deviating from the mold 100 in the Figure 1, the molding tool 100a further comprises a support mechanism. The support mechanism comprises at least one support element 185, which is coupled to at least one second actuating device 188. The at least one second actuating device 188 and the at least one support element 185 are arranged in the lower tool part 140. The at least one support element 185 has a support surface 185a (see Figure 3c ) and a lower stop element 166 for the pre-cut. The at least one second actuating device 188 can in turn be designed as a pneumatic, hydraulic, or electromechanical actuating device. The function of the at least one support element 185 and the at least one second actuating device 188 is described in detail in connection with the following figures.

[0063] Furthermore, the lower tool part 140 can have at least one lower stop element 168 for the final cut, corresponding to the at least one stop element 164 of the upper tool part 120. The function of the stop elements 164 and 168 will be described in more detail below.

[0064] In connection with the Figures 3a to 3j the production of at least one article 11 (see Figure 3j ) from a flat material sheet 10, in particular from a natural fiber sheet, using the forming tool 100a. Figures 3a to 3j show the actuation of the forming tool 100a during a forming cycle.

[0065] In Figure 3athe forming tool 100a is in the open state, in which the two tool parts 120, 140 are moved apart. The material sheet 10 to be formed is positioned between the two tool parts 120, 140 (for example, with the aid of a conveyor device). The at least one cutting element 182 of the cutting device 180 is located in Figure 3a still in the engaged state. The positioned material sheet 10 can, for example, be a material sheet made of natural fibers, in particular cellulose.

[0066] In Figure 3bthe forming tool 100a remains in the open or at least partially open state. The at least one cutting element 182 is disengaged with the aid of the at least one actuating device 184 coupled to the at least one cutting element 182. In this case, the at least one cutting element 182 moves essentially perpendicularly from the carrier device 142 of the lower tool part 140 in the direction of the material sheet 10 arranged above it. This disengaging movement is indicated in Figure 3b by the arrows 31. The at least one cutting element 182 is disengaged until the cutting element 182 or the tip of the at least one cutting element 182 is located just below the material sheet 10. The at least one cutting element 182 does not yet touch the sheet 10 in the disengaged position.

[0067] With the aid of the at least one second actuating device 188, the at least one support element 185 is now moved in the direction of the at least one disengaged cutting element 182, so that at least one section (see section with support surface 185a in Figure 3c ) of the at least one support element 185 engages under the at least one cutting element 182. In the Figure 3c In the implementation shown, the at least one support element 185 is moved horizontally inwards (see arrows 32 in the Figure 3c). As a result, a support element 184a of the actuating device 184 can rest on the support surface 185a of the at least one support element 185. The at least one support element 185 thus has the function of supporting the at least one cutting element 182 during the cutting process and thus relieving the load on the actuating device 184. The cutting forces (punching forces) acting on the cutting element 182 during cutting (punching) rest on the support element 185. The load on the actuating device 184, which implements, for example, a pneumatic or hydraulic lifting mechanism, is thus relieved.

[0068] Subsequently, the upper tool part 120 is lowered until the upper stop element 162 comes into contact with the lower stop element 166. This lowering movement of the upper tool part 100a is indicated by downward-pointing arrows 33 in the 3D figures and 3eAs a result of the lowering movement, the upper tool part 120 comes into contact with the material sheet 10 (see Figure 3d ) and presses it in the direction of the at least one cutting element 182. As a result, the sheet 10 is pre-cut or pre-punched at the location of the at least one disengaged cutting element 182, even before the sheet 10 undergoes any significant deformation (see Figure 3e ). This pre-cut serves as a controlled relief cut and ensures that the flat sheet 10 can be more easily formed into a three-dimensional shape.

[0069] As in the Figures 3a to 3jAs indicated schematically, the at least one cutting element is arranged at or near the outer edge of the mold (or of the two mold halves 130, 134) and thus creates a cut in the sheet 10 at or near the outer edge of the article 11 to be produced, where the transition from the flat sheet to the three-dimensional article is. This is where the greatest forming forces (tensile forces) occur during forming. In this way, uncontrolled cracks during forming can be eliminated or greatly reduced, thereby significantly reducing the amount of defective articles that are rejected.

[0070] Following the cutting process, the upper tool 120 is slightly raised again. This is indicated by arrow 34 in Figure 3fclarifies. Due to the lifting movement, the upper tool part 120 is again slightly moved away from the lower tool part 140. This allows the at least one counter-cutting element 186 to detach from the disengaged and supported cutting element 182 located underneath. No significant load now acts on the at least one cutting element 182, so that the at least one support element 185 can be moved horizontally outwards, i.e. away from the at least one cutting element 182, by the at least one second actuating device 188. This horizontal outward movement of the support element 185 is indicated by arrows 35 in the Figure 3g indicated.

[0071] Subsequently, the at least one cutting element 182 which is no longer supported can be re-engaged by means of the at least one actuating device 184. This movement is indicated by arrows 36 in the Figure 3h indicated, whereby Figure 3hshows the state in which the at least one cutting element 182 is fully engaged.

[0072] The upper tool part 120 is now lowered onto the lower tool part 140 (see arrow 37 in Figure 3i ) until the upper stop element 164 comes into contact with the corresponding lower stop element 168. The forming tool 100a is now closed (see Figure 3i ).

[0073] By lowering the upper tool part 120 onto the lower tool part 140, the material sheet 10 arranged between the two mold halves 130, 134 is formed into the at least one article 11. Furthermore, the at least one article 11 is finish-cut at its outer edge using the cutting line 150 (or cutting edge) as soon as the mold 100a is closed. Finish-cutting means that the formed article 11 is separated from the material sheet 10. The forming of the material sheet 10 into the three-dimensional article 11 is now complete.

[0074] The upper tool part 120 is now moved away from the lower tool 140, i.e. lifted. This lifting movement is indicated by arrow 38 in Figure 3j clarified. Figure 3j shows the mold 100a in the open state (starting position). The article 11 can be removed by means of a removal device (in the Figure 3j(not shown). A section of the material sheet 10 can then be advanced using a conveyor device (not shown in detail). A new forming cycle can then begin.

[0075] In connection with the Figure 4 a further forming tool 100b is described, which differs from the forming tool 100a of the Figures 3a to 3j differs primarily in the support mechanism. This is described in more detail below. All other elements of the mold 100b are identical or fulfill the same function as the elements in the mold 100a and are therefore not described again. Rather, reference is made to the corresponding description of the mold 100a in connection with the Figures 3a to 3j referred to above.

[0076] Figure 4shows the mold 100b in a partially opened state, in which the material sheet 10 between the two mold halves 130, 134 has not yet been significantly deformed. The at least one cutting element 182 is located in its disengaged position below the material sheet 10. The disengagement of the at least one cutting element 182 can be carried out with the aid of the at least one actuating device 184, as described in connection with the Figure 3b and the forming tool 100a as described above. The disengagement movement is indicated by the arrow 41 in Figure 4 indicated.

[0077] The support mechanism of the forming tool 100b comprises at least one second actuating device 188 and at least one roller element 185d coupled to the at least one second actuating device 188. The at least one roller element 185d is arranged such that it can roll on a beveled support surface 185c of at least one support element 185b. The at least one support element 185b, the at least one roller element 185d, and the at least one actuating device 188 coupled to the at least one roller element 185d are each arranged in the lower tool part 140. In particular, the at least one support element 185b and roller element 185d are arranged below the at least one cutting element 182.

[0078] To support the at least one actuating device 184 (or the at least one cutting element 182) during the cutting (punching) of the material sheet 10, the at least one roller element 185d is disengaged. In this case, the at least one roller element 185d is displaced (horizontally) inwardly (i.e., in the direction of the lower mold half 134) with the aid of the at least one second actuating device 188, which is indicated by the arrow 44 in the Figure 4 is indicated. The at least one roller element 185d is brought into a position below the support element 185b by the disengagement. The support element 185b located above rests with its (outwardly) beveled support surface 185c on the disengaged roller element 185d.

[0079] The at least one second actuating device 188 is further configured to exert a supporting force on the at least one disengaged roller element 185d, the magnitude of which approximately corresponds to the punching force exerted on the at least one cutting element 182 during cutting (punching). The upper tool part 120 is now lowered until the at least one counter-cutting element 186 comes into contact with the at least one underlying cutting element 182 and exerts a desired punching force thereon to cut through the material sheet 10 (represented by arrow 42 in Figure 4 ). The punching force exerted on the at least one cutting element 182 is substantially compensated by the supporting force applied by the underlying support mechanism, which counteracts the punching force, thereby relieving the load on the actuating device 184.

[0080] After the punching process, the first tool part 120 is lowered further. At the same time, the supporting force built up by the second actuating device 188 can be reduced again. Due to the resulting force imbalance, the at least one supporting element 185b is moved downwards together with the at least one cutting element 182 (see arrow 45 in the Figure 4 , which indicates this movement). Due to the downward movement of the at least one support element 185b, the at least one roller element 185d arranged underneath rolls outwards along the bevelled support surface 185c. This movement is indicated by the arrows 46 in the Figure 4 indicated schematically. The at least one roller element 185d and the cooperating support element 185b are then returned to their engaged position. The forming tool 100b can now be completely closed and the material sheet 10 can be completely formed.

[0081] The advantage of the associated with the Figure 4 The advantage of the support mechanism described is that the upper tool part 120 does not have to be raised again in order to be able to re-engage the at least one support element 185b and the roller element 185d with the aid of the second actuating device 188. Rather, the at least one roller element 185d is simply pushed outwards by the beveled support surface 185c as the upper tool part 120 continues to move towards the lower tool part 140. A brief lifting of the upper tool part 120, as described above in connection with the molding tool 100a, is therefore no longer necessary to release the support mechanism for engagement. The molding process can thus be further accelerated.

[0082] The forming technique described here is particularly suitable for material sheets, which exhibit lower elasticity than thermoplastic films and are therefore more difficult to form. By creating local cuts (pre-cuts) in the material sheet, it is possible to increase its flexibility and thus improve the forming process into three-dimensional articles.

Claims

1. Molding tool (100, 100a, 100b) for reshaping a sheet of material (10) into at least one three-dimensional article (11), wherein the molding tool (100, 100a, 100b) is adapted to occupy optionally an open and a closed state, wherein the molding tool (100, 100a, 100b) comprises: a first tool part (120) and a second tool part (140) that works together with the first tool part (120), wherein in the closed state of the molding tool (100, 100a, 100b), the two tool parts (120, 140) are moved toward one another, and wherein in the open state of the molding tool (100, 100a, 100b), the two tool parts (120, 140) are moved away from one another; a first mold half (130) arranged in the first tool part (120) and a second mold half (134) arranged in the second tool part (140), wherein the two mold halves (130, 134) are adapted for reshaping the sheet of material (10) arranged between the two tool parts (120, 140) into at least one three-dimensional article (11) when the two tool parts (120, 140) are moved toward one another; and a cutting device (180) comprising at least one cutting element (182) and at least one actuating device (184) coupled to the at least one cutting element (182), wherein the at least one actuating device (184) is adapted to extend the at least one cutting element (182) in the direction of the sheet of material (10), arranged between the two tool parts (120, 140), in order to cut the sheet of material (10), characterized in that the molding tool (100, 100a, 100b) is adapted such that the molding tool (100, 100a, 100b) is in the open state or in a partially open state during this process.

2. Molding tool (100, 100a, 100b) according to claim 1, wherein the at least one actuating device (184) is adapted to retract again the at least one cutting element (182) after the sheet of material (10) is cut.

3. Molding tool (100, 100a, 100b) according to one of the preceding claims, wherein the at least one cutting element (182) is arranged in the molding tool (100, 100a, 100b) in such a way that in the extended position, it at least partially precuts or cuts the sheet of material (10) on the outer edge of the article (11) that is to be molded or is already molded or close to the outer edge of the article (11) that is to be molded or is already molded.

4. Molding tool (100, 100a, 100b) according to one of the preceding claims, wherein the at least one cutting element (182) is arranged in the first tool part (120) and / or in the second tool part (140) and / or wherein the at least one actuating device (184) is arranged in the first tool part (120) and / or in the second tool part (140).

5. Molding tool (100, 100a, 100b) according to one of the preceding claims, wherein the cutting device (180) further comprises at least one opposing cutting element (186) that works together with the at least one cutting element (182), wherein, optionally, the at least one opposing cutting element (186) is arranged in the tool part (120 or 140) opposite to the extendable cutting element (182).

6. Molding tool (100, 100a, 100b) according to one of the preceding claims, wherein the extendable cutting element (182) comprises at least one blade.

7. Molding tool (100, 100a, 100b) according to one of the preceding claims, wherein the at least one actuating device (184) comprises an extending and retracting mechanism driven pneumatically, hydraulically, or electromechanically.

8. Molding tool (100, 100a, 100b) according to one of the preceding claims, further comprising: at least one support mechanism (188, 185, 185a-d) that is provided for supporting the at least one extended cutting element (182) and / or at least one cutting line (150), arranged in the first and / or second tool part (120, 140), for final-cutting the at least one molded article (11).

9. Molding tool (100, 100a, 100b) according to one of the preceding claims, wherein the sheet of material (10) consists primarily of fibers, in particular natural fibers.

10. Use of a molding tool (100, 100a, 100b) according to one of claims 1 to 9 for producing at least one three-dimensional article (11) from a laminar sheet of material (10), in particular a laminar sheet of material (10) made of natural fibers.

11. Molding machine (1) for producing at least one article (11) from a laminar sheet of material (10), comprising: the molding tool (100, 100a, 100b) according to one of claims 1 to 9; an upper table (2) for accommodating the first tool part (120) of the molding tool (100, 100a, 100b); and a lower table (3) for accommodating the second tool part (140) of the molding tool (100, 100a, 100b), wherein the upper table (2) and / or the lower table (3) is / are movably mounted.

12. Method (200) for producing at least one three-dimensional article (11) from a laminar sheet of material (10), comprising the following steps: - providing (S201) a molding tool (100, 100a, 100b) according to one of claims 1 to 9; - arranging (S202) the laminar sheet of material (10) between the two mold halves (130, 134) of the molding tool (100, 100a, 100b); - extending (S203) the at least one cutting element (182) of the molding tool (100, 100a, 100b) in the direction of the sheet of material (10) arranged between the two mold halves (130, 134); - cutting (S204) the sheet of material (10) using the at least one cutting element (182) with the molding tool (100, 100a, 100b) being open or at least partially open; - retracting (S205) the at least one cutting element (182) after the sheet of material (10) was cut; and - subsequently closing (S206) the molding tool (100, 100a, 100b) and reshaping the sheet of material (10) to form at least one three-dimensional article (11).

13. Method according to claim 12, wherein the cutting using the extendable cutting element (182) comprises a precutting of the sheet of material, and wherein the method further comprises: - final-cutting of the at least one formed article (11) in order to separate the article (11) from the sheet of material (10).

14. Method according to claim 12 or 13, wherein the extension comprises a positioning of the at least one cutting element (182) directly below or above the sheet of material (10), and wherein the step of cutting comprises a movement of the tool part, opposite to the at least one cutting element (182), in the direction of the cutting element (182), until the at least one opposing cutting element (186) comes into contact with the at least one cutting element (182), and wherein the step of retracting the at least one extended cutting element (182) comprises moving the tool part with the at least one opposing cutting element (186) away from the at least one cutting element (182) in order to release the at least one cutting element (182) for retraction.

15. Method for producing at least one three-dimensional article (11) from a laminar sheet of material (10), comprising the following steps: - providing a molding tool (100, 100a, 100b) according to one of claims 1 to 13; - arranging the laminar sheet of material (10) between the two mold halves (130, 134) of the molding tool (100, 100a, 100b); - closing the molding tool (100, 100a, 100b) and reshaping the sheet of material (10) to form at least one three-dimensional article (11); - extending the at least one cutting element (182) of the molding tool (100, 100a, 100b); and - cutting-out, using the at least one extended cutting element (182), of the at least one three-dimensional article (11) from the sheet of material (10), wherein the steps of extending and cutting-out are performed when the molding tool (100, 100a, 100b) is in the open state or in a partially open state.