EP3140200B1 - Method and device for producing molded parts from a continuous fiber-material sheet - Google Patents

Description

The invention relates to a method and an apparatus for producing three-dimensional molded parts from a web of a flat, plastically deformable fiber material. In particular nonwoven, paper, cardboard or cardboard can be formed by deep drawing of sheet metal similar forming process (hereinafter referred to as deep drawing) to form a molding.

Through multidimensional forming, the application potential of metals is exploited for metals and plastics. For nonwoven, paper, cardboard and cardboard, a multi-dimensional forming with low forming ratio by embossing has so far been widespread. The drawing process, on the other hand, has a high potential for the use of hollow containers with a high forming ratio closed on one side, but has hitherto been used only in marginal areas and there is a low level of scientifically proven knowledge. The reason for this is the forming behavior of the material. A flowable state as in plastics and metals is not achieved. In practice, the risk of further development or the use of innovative geometric shapes is too high, as long as there is no knowledge base on the geometric possibilities that ensure process-reliable operation. For this reason, drawing machines are designed for simple formats in their operation and the potential of the drawing process is not exploited in terms of quality of the moldings, shape design and flexibility of machines. ( Hauptmann, M. 2010: Targeted process control and possibilities for process monitoring in the multi-dimensional forming of cardboard by drawing. Dresden: Dissertation TU Dresden , 2010.)

At present, during deep drawing, a blank of suitable size and shape is supplied to the manufacturing process, the edges of which are dimensioned such that the material forms in the shell area and wrinkles when it is drawn into the matrix by the punch, and thus in this area a smaller area than that Cutting receives. The original area is reduced by the folding. Such a method is for example from the document DE 176 1 002 B known.

Since the blank can easily be pulled into the gap between punch and die with the stamp movement, only a slight tensile load acts on the bottom of the molded part to be produced. To obtain the blank, it is cut in advance from the board web in an additional process step and must be kept ready and prepared by appropriate handling and storage devices for the subsequent deep drawing. Out US 4,313,899 It is known to heat and moisturize a web and to deform it by means of heated tools in order to achieve a high forming ratio without damage. According to the state of the art, methods are also known which allow the forming directly from the board web without prior blanking. Exemplary for this are the documents DE 692 2 1490 T2 and DE 20 2012 102 550 U1 cited. In this case, a coated cardboard is used, which has a higher tensile strength. In addition, special board is known, which is costly, but also has a higher tensile strength. Despite these measures, however, only forming ratios (ratio of diameter to depth of the formed area) of 0.15 to 0.2 are possible with the forming method according to the prior art. Higher forming ratios fail because the material associated with the web is prevented from entering the gap between the punch and die without additional tensile forces. The resulting tensile forces acting on the material, especially in the region of the bottom of the molded part, lead to cracks in the material. This allows for only 3 to 6% elongation, then it comes to breakage. The molding is thus unusable. The above figures are the book Hesse, Fritz and Hans - Jürgen Tenzer, Foundations of paper processing . Volume 1 to 3, book publisher, 1966 taken.

It is therefore the object of the present invention to provide a method and an apparatus for producing three-dimensional molded parts from a fiber material, in which the forming takes place by deep drawing from a blank located in the web of the material and leads to a high forming ratio.

The object is achieved by a method for producing three-dimensional molded parts from a web of a flat, plastically deformable fiber material by deep drawing with a punch and an associated draw bush. A fiber material usually has a low tensile strength, however, undergoes high friction by strong compression in the drawing gap. As a result, the material is subjected to high loads when it is drawn into the gap between the punch and the drawing sleeve, which leads to breakage of the material.

By a relative movement between the punch and the Ziehbüchse the fiber material is deformable. The targeted permitting or even controlling this compensation movement ensures that the material can reshape without being held back in the sheet plane and thus to obtain expansion cracks. In this case, a round, rectangular, oval or irregular blank for the molding during deep drawing with the web of fiber material of different grammage is connected via at least one web and solved by the way by at least one relief cut from the web. wherein a forming ratio as a ratio of diameter and depth greater than 0.2 is feasible.

Thus, the advantages of deep-drawing a single blank, which can already be achieved in the prior art high forming ratios, with the advantages of processing a web, i. a virtually infinitely feedable to the process sheet material, linked. While usually the forming of web material is possible only to a small extent, namely with forming ratios of 0.15 to 0.2. Basically, however, embossing is done instead of deep drawing with forming ratios around 0.05. This disadvantage is overcome by the invention. The present as a web material allows a very simple handling, since a manipulation of individual blanks is eliminated. This is particularly interesting for non-rotationally symmetric blanks, which must be brought into an exact position in each axis before the deep-drawing process can begin.

In addition, it is also possible to use the continuing connection with the web for subsequent method steps which follow the shaping by deep drawing. Thus, the molded part produced can be easily transported and placed in an exact location without the need for additional expenses would be required. It can be done, for example, a filling and closing of the formed as a packaging molding.

In the preferred embodiment of the invention nonwovens, paper, cardboard or paperboard are provided as a flat, plastically deformable fiber material. With these materials, especially paper and cardboard, a good deformation is guaranteed, even if no special materials whose properties are specifically designed for deep drawing, apply. In addition, paper and board are particularly suitable after deep drawing as a product with sufficient stability to be used, for example as packaging for packaging other products.

It has been shown in a particularly advantageous manner that high deformation ratios can be realized to 0.9 by the deep-drawing process provided according to the invention. This is possible in the prior art only if separate, completely cut out of a material context blanks are fed to the deep drawing process individually. Particularly preferred according to the invention forming ratios of 0.6 to 0.8 can be realized.

Further advantages result from the fact that multipart packaging components are adjustable. It is then unnecessary to produce these components in individual manufacturing steps and subsequently connect them together, including the respectively necessary manipulation steps, with which they would have to be brought into the required position for the connection to each other.

In this context, for example, a lower shell, an upper shell and a lower shell and upper shell movable connecting hinge can be produced. By the hinge can later, for example, after filling the lower shell, the upper shell are folded and the entire molded part are closed. Such an application would be particularly advantageous in the field of packaging.

Preferably, according to the invention, the deep-drawing is carried out in a closed process. In this case, the molding after the deep drawing, wherein the blank is pressed by the stamp in the Ziehbüchse, ejected out of this in the opposite direction. This allows the molded part after its production continue to remain in conjunction with the web and be supplied according to the aforementioned possibilities of further manipulation or subsequent process steps.

In contrast, if the open method is used, which is not part of the invention in which the molded part produced from the drawing sleeve in the same direction as the punch has pressed the blank is ejected, the bond with the web must be solved beforehand. This can be done by a complete cutting of the blank prior to deep drawing and would be useful, for example, when deep drawing at the same time represents the final production step and no further process steps would have to follow.

Particular advantages are associated with a compensating movement, which is carried out either as a passive compensating movement and in which the web is free to move during the forming process or which can be carried out as an active compensating movement and in which the punch and the draw sleeve during the forming process are moved so that they with the midpoint shift of the center at the transition from the blank to the molded part to the center of the relief section. Both variants can also be used in parallel. The compensation movement serves for the free flow of material during forming. Without this compensating movement no symmetrical deep moldings can be made. Holding the web relative to the tools hinders the leveling movement. This leads to unevenly high moldings or tearing off the web.

Particular advantages accrue from the invention in the case that the deep-drawing is carried out on a form, fill and seal machine and at the same time at various stations, the steps of producing the molding as a packaging or container, transporting the web with the containers to the filling device, filling the Container, transport of the web with the containers to the closing device, closing the container, separating the individual containers or in units from the web to be performed. Then, as already stated above, a manipulation of the moldings and the resulting package in a simple manner to the remaining web material, for example, at the edge, take place. The molded parts and later the packing remain in a defined position and need not be manipulated in order to carry out the subsequent process steps. Once the package has been produced, the individual packages can be released from the composite with the material band, either individually or in groups, according to the need for subsequent logistics processes.

The object of the invention is also achieved by a device according to claim 10 for carrying out a deep drawing process for a flat, plastically deformable fiber material according to the invention described above. This device consists of a deep-drawing device, as is known in the prior art for fiber materials, and a process associated with this cutting device. The A cutting device is for cutting or punching one or more relief cuts, leaving one or more webs with which the blank remains connected to the web. The cutting device can be placed directly on the thermoforming device and cut the web material in the same position, as the subsequent deep-drawing takes place. The web is thus not moved between the two process steps, which can follow one another directly.

Alternatively, it is provided that the cutting device is spaced from the thermoforming device, so that the first cutting takes place, the web is then transported a process step further until it has reached the thermoforming device, so that there the deep drawing can be made. The object of the invention is further achieved by a form, fill and seal machine according to claim 13, comprising at least one of the above-described molding devices, in particular thermoforming devices. The thermoforming device is arranged and designed so that it forms a sheet-like, plastically deformable fiber material open-topped containers as moldings. The form, fill and seal machine has at least one filling device arranged and configured to fill the open-topped containers. In addition, it has at least one closing device, which is arranged and designed such that it closes the open upper sides of the filled containers. Furthermore, a transport or container conveying device is provided, which is designed such that it conveys the web, which extends past the forming device, the filling device and the closing device, along the molding device, the filling device and the closing device, and wherein , Filling and closing machine further comprises a separating device which is designed and arranged so that it separates the webs in such a way that individual containers or units of a plurality of containers are cut out of the web.

A further advantage of the invention is that the machine performance can be used continuously, since there are different process stages for a plurality of deep-drawing punches which are inserted into the drawing sleeve at different times. This is particularly advantageous because when deep drawing of fleece, paper, cardboard or cardboard at the beginning of the deep drawing process, the greatest force must be spent.

• Fig. 1: Stand der Technik; Ergebnisse von Ziehversuchen nach herkömmlichen Verfahren bei hohem Umformverhältnis mit Schäden im Bodenbereich;
• Fig. 2: schematische Darstellung einer Ausführungsform der Umformergebnisse bei der Nutzung des erfindungsgemäßen Verfahrens in Draufsicht;
• Fig. 3: schematische Darstellung einer Ausführungsform der Umformergebnisse bei der Nutzung des erfindungsgemäßen Verfahrens in perspektivischer Ansicht;
• Fig. 4: schematische Darstellung einer Ausführungsform der erfindungsgemäßen Tiefziehvorrichtung in geschnittener Seitenansicht;
• Fig. 5: schematische Darstellung der erfindungsgemäßen Verfahrensschritte in geschnittener Darstellung der Umformvorrichtung;
• Fig. 6: schematische Darstellung einer Form-, Füll- und Verschließmaschine mit einer Ausführungsform der erfindungsgemäßen Umformvorrichtung; und
• Fig. 7: den Ablauf und die Funktion der Ausgleichsbewegung.

Further details, features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

• Fig. 1 : State of the art; Results of drawing tests according to conventional methods at high forming ratio with damage in the soil area;
• Fig. 2 : schematic representation of an embodiment of the forming results in the use of the method according to the invention in plan view;
• Fig. 3 : schematic representation of an embodiment of the forming results when using the method according to the invention in a perspective view;
• Fig. 4 : schematic representation of an embodiment of the deep-drawing device according to the invention in a sectional side view;
• Fig. 5 : schematic representation of the method steps according to the invention in a sectional view of the forming device;
• Fig. 6 : schematic representation of a form, fill and seal machine with an embodiment of the forming device according to the invention; and
• Fig. 7 : the process and the function of the compensation movement.

Fig. 1 shows the state of the art with results of drawing tests according to conventional methods at high forming ratio with resulting damage in the soil area. By existing during the drawing process complete compound of the molded part with the web 1 is a free and largely unhindered sliding material into the drawing gap or only possible by overcoming higher forces. The result is overloading of the material by train, it comes to the fraction 3 of the composite material and the molded parts 2 'is therefore useless. Shown are different variants of fractures 3 in the floor area. Likewise, it can cause breaks 3 in the wall of the fiber material, since there especially in the deep drawing of fiber materials, the highest stresses occur, always depending on the coefficient of friction between the punch and fiber material such. B. cardboard.

Fig. 2 shows a schematic representation of an embodiment of the forming results in the use of the method according to the invention in plan view. In this case, molded parts 2 'have been formed by deep drawing, which are still connected to the web 1 via a web 5. The remaining areas in which the blank for the molded part 2 'was originally connected to the web 1, are by a Relief section 4 has been separated. There, the material of the web 1 was pulled without hindrance during deep drawing in the drawing gap, so that a defect-free molded part 2 'could be formed.

Fig. 3 shows a schematic representation of an embodiment of the forming results in the use of the method according to the invention in a perspective view. In this case, molded parts 2 'have been formed in two rows in the web 1. The moldings are also connected via a web 5 still with the web 1 and separated by way of relief cuts from the web 1.

Fig. 4 shows a schematic representation of an embodiment of the deep-drawing device 6 according to the invention in a sectional side view. In this case, the web 1 is located in the deep-drawing device 6 so that it covers the opening of the drawing bushing 7. In order to obtain a suitable blank 2, the cutting devices 11 are provided which make at least one relief cut 4 in the web 1 in cooperation with the counter cutters 12. As a result, in the case of the subsequent deep-drawing process, not shown here, when the punch 8 sinks into the draw bush 7, the blank 2 can be formed almost unhindered into the draw gap between the draw bush 7 and the punch 8.

First, however, the blank 2 with the fold holder 9, which presses against the draw sleeve 7, fixed so far that the insertion of the blank 2 takes place in the drawing gap against a defined frictional force and without excessive wrinkling. If the molded part is produced, it pushes the counter-holder 13 in the direction of the punch 8, which has now left the drawing sleeve 7 against the forming again, from.

Fig. 5 shows a schematic representation of an embodiment of the method steps according to the invention by means of cut representations of the forming device 6, but here without the cutting devices 11, 12. These are not arranged directly on the deep-drawing device 6 according to the illustrated embodiment, but come in an upstream process step to effect. Therefore, in process step a), the web 1 reaches the forming device 6 with already introduced relief cuts, which, however, are not visible in the selected representation.

In process step b), the punch 8 is placed on the blank 2 in the direction of the arrow. A heater 10 heats the Ziehbüchse 7. The actual forming process takes place in process step c), wherein the punch 8 further lowers in the arrow direction and pushes the blank 2 in the Ziehbüchse 7. There, the now formed molding 2 'is fixed by the heat treatment in its shape. Finally, the shaping follows, as shown in process step d), in that the counterholder 13 ejects the fixed molded part 2 'from the mold, the drawing bushing 7.

Fig. 6 shows a schematic representation of a form, fill and seal machine with an embodiment of the forming device 6. In process step a), the formation of the molding 2 'by means of a deep-drawing device 6 according to the invention is performed. The molding 2' is designed as a packaging. This is filled in process step b) by means of the filling device 30 with the packaged goods. This is followed by process step c) in which a closure is fastened on the molded part 2 'by the closing device 31.

Until then, the now formed pack is still connected to the web 1, which ensures easier handling and exact positioning. However, in order to prepare the package for delivery, it is necessary to separate it from the web 1. This takes place in a further station, the separating device 32. Thus, in process step e), there is now a single or grouped pack as required, which can be removed and prepared for shipping or the required logistical further treatment.

The web 1 is transported by means of a transport device 33 and thus the molded part 2 'from station to station, as described above, promoted.

Fig. 7 shows the sequence and the function of the passive compensation movement during deep drawing with an initial state a), an intermediate state b) and a final state c) in each case in side view and plan view. In this case, the web 1 with the blanks 2 and later the molded part 2 'can be seen, the latter being connected by the web 5 to the web 1.

While the center M1 of the relief cut 4 before forming coincides with the center M2 of the (future) molded part 2 ', this changes during forming as material of the blank 2 is drawn into the drawing nip. There the molding is fixed on one side over the web in the web, while the material flow takes place only on one side, so that the web must either be free to immigrate the amount of compensating movement 40 (passive, as shown) or the tools, ie stamp and Ziehbüchse, so be moved so that they are carried along with the center shift (active compensation movement, not shown).

LIST OF REFERENCE NUMBERS

1

train

2

Blank for molding

2 '

moldings

3

fracture

4

relief cut

5

web

6

Deep-drawing device

7

drawing box

8th

stamp

9

blank holder

10

heater

11

cutter

12

against cutting

13

backstop

30

filling

31

sealer

32

separating device

33

transport device

M1

Center relief punching

M2

Centerpiece molding

40

passive compensation movement

Claims (13)

1. A method for manufacturing three-dimensional shaped parts from a continuous sheet of flat, plastically shapable fibrous material by deep drawing with a punch and an associated drawing die, the fibrous material being reshapable between the punch and the drawing die through relative movement, characterized in that during the deep drawing a round, rectangular, oval or irregular blank (2) for the shaped part (2') is connected to the continuous sheet (1) of fibrous material via at least one web and is otherwise detached from the continuous sheet (1) by at least one relief cut (4), wherein a reshaping ratio, which is a ratio of diameter to depth, of greater than 0,2 is feasible.
2. The method according to claim 1, wherein non-woven fabric, paper, cardboard or paperboard are provided as flat, plastically shapable fibrous material.
3. The method according to claim 1 or 2, wherein reshaping ratios of 0.3 to 0.9 are feasible.
4. The method according to any one of the preceding claims, wherein reshaping ratios of 0.6 to 0.8 are feasible.
5. The method according to any one of the preceding claims, wherein multipart packaging components are manufacturable.
6. The method according to claim 5, wherein a lower tray, an upper tray and a hinge movably connecting the lower tray and the upper tray are manufacturable.
7. The method according to any one of the preceding claims, wherein the deep drawing is carried out in a closed process.
8. The method according to any one of the preceding claims, wherein a compensation movement is provided, which can be carried out as a passive compensation movement (40), wherein the continuous sheet (1) is free to follow along during the reshaping operation, and/or which can be carried out as an active compensation movement, wherein the punch (8) and the drawing die (7) are moved during the reshaping operation such that they are carried along with the center point shift of the center point (M2) relative to the center point (M1) of the relief cut (4) during the transition from the blank (2) to the shaped part (2').
9. The method according to any one of the preceding claims, wherein the deep drawing is carried out at a shaping, filling and closing machine, and the steps of manufacturing the shaped part (2') as a container in the deep drawing device (6), transporting the continuous sheet (1) with the containers to a filling device (30), filling the container inside the filling device (30), transporting the continuous sheet with the containers to a closing device (31), closing the container inside the closing device (31), separating the containers individually or in units from the continuous sheet inside the separating device (32) are carried out simultaneously at different stations.
10. A device for manufacturing three-dimensional shaped parts (2') from a continuous sheet (1) of a flat, plastically shapable fibrous material by deep drawing, including a punch (8) and an associated drawing die (7), which form a deep drawing device (6), the fibrous material being reshapable between the punch (8) and the drawing die (7) through relative movement of the punch (8) and the drawing die (7), characterized in that the deep drawing device (6) and a procedurally linked cutting device (11, 12) are provided, wherein a round, rectangular, oval or irregular blank (2) for the shaped part (2') can be cut out from the continuous sheet (1) of fibrous material by means of at least one relief cut (4) using the cutting device (11, 12) in such a manner that the blank (2) remains connected to the continuous sheet (1) via at least one web (5) and is otherwise detached from the continuous sheet (1) by the relief cut (4).
11. The device according to claim 10, wherein the deep drawing device (6) is arranged in the region of the cutting device (11, 12), so that the continuous web (1) is cut and the deep drawing is subsequently performed without the continuous sheet (1) being carried further.
12. The device according to claim 10, wherein the deep drawing device (6) and the cutting device (11, 12) are spaced from one another, so that the cutting out is performed first and the deep drawing is performed after further transport of the continuous sheet (1) to the deep drawing device (6).
13. A shaping, filling and closing machine, including at least one deep drawing device for forming open-top containers as shaped parts (2'), at least one filling device (30) arranged and configured to fill the open-top containers, at least one closing device (31) arranged and configured to close the open top sides of the filled containers, and a transport device (33) configured to convey the continuous sheet (1), which extends along the deep drawing device (6), the filling device (30) and the closing device (31), along the deep drawing device, the filling device (30) and the closing device (31), wherein the shaping, filling and closing machine further includes a separating device (32) configured and arranged to separate webs between the continuous sheet (1) and shaped parts (2') in such a manner that individual containers or units of multiple containers are thereby cut out from the continuous sheet (1), characterized in that at least one device according to any one of claims 10 to 12 is provided for the forming of containers as shaped parts (2').

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