Method and Device for Producing Molded Parts from a Continuous Fiber-Material Sheet

Abstract

The invention relates to a method and a device for producing three-dimensional molded parts from a continuous sheet of a flat, plastically malleable fiber material via deep drawing with a stamp and an associated die, wherein the fiber material between the stamp and the die can be reshaped via a relative movement.

The object of the instant invention is to offer a method and a device for producing three-dimensional molded parts in which the reshaping is done via deep drawing from a cut-to-size section in the continuous sheet and which leads to a high reshaping ratio. The problem is solved by connecting the round, rectangular, oval or irregular cut-to-size section for the molded part during the deep-drawing process to the continuous sheet of fiber material via at least one web and otherwise separating it from the continuous sheet via at least one stress-easing cut; a reshaping ratio, as the ratio of the diameter and the depth, of greater than 0.2 can be realized.

Claims

1. A method for producing three-dimensional molded parts from a continuous sheet of a flat, plastically malleable fiber material via deep drawing with a stamp and an associated drawing case, wherein the fiber material between the stamp and the drawing case can be reshaped via a relative movement, wherein a round, rectangular, oval or irregular cut-to-size section for the molded part is connected during the deep-drawing process with the continuous sheet of fiber material via at least one web and is otherwise separated from the continuous sheet via at least one stress-easing cut, wherein a reshaping ratio, as the ratio of the diameter and the depth, of greater than 0.2 is realized.

2. The method according to claim 1, wherein fleece, paper, paperboard or cardboard is provided as the flat, plastically malleable fiber material.

3. The method according to claim 1, wherein reshaping ratios of 0.3 to 0.9 are realized.

4. The method according to claim 1, wherein reshaping ratios of 0.6 to 0.8 are realized.

5. The method according to claim 1, wherein multi-part packaging components are produced.

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 manufactured in connection with this.

7. The method according to claim 1, wherein the deep drawing is carried out in a closed process.

8. The method according to claim 1, wherein a compensation movement is provided that can be carried out as a passive compensation movement, wherein the continuous sheet is free to subsequently move along during the reshaping process, or/and as an active compensation movement, wherein the stamp and the drawing case are moved in such a way during the reshaping process that they can be carried along with the shifting of a center point M2 during the transition from the cut-to-size section to the molded part with respect to a center point M1 of the stress-easing cut.

9. The method according to claim 1, wherein the deep drawing is carried out on a shaping, filling and closing machine and the following steps are simultaneously carried out at various stations: production of the molded part as a container in a deep-drawing device, transport of the continuous sheet with the containers to a filling device, filing the container in the filling device, transport of the continuous sheet with the containers to a closing device, closing the container in the closing device, separating the container individually or in units from the continuous sheet in a separation device.

10. A device for producing three-dimensional molded parts from a continuous sheet of a flat, plastically malleable fiber material via deep drawing, comprised of a stamp and an associated drawing case, which form a deep-drawing device wherein the fiber material between the stamp and the drawing case is reshaped via a relative movement of the stamp and drawing case, wherein the deep-drawing device and a cutting device connected to it in a process-related way are provided, wherein a round, rectangular, oval or irregular cut-to-size section for the molded part is cut out of the continuous sheet (1) made of fiber material via at least one stress-easing cut with the cutting device in such a way that the cut-to-size section remains connected via at least one web to the continuous sheet and is otherwise separated from the continuous sheet via the stress-easing cut.

11. The device according to claim 10, wherein the deep-drawing device is arranged in the area of the cutting device so that the continuous sheet is cut and the deep drawing is subsequently done without the continuous sheet being moved further.

12. The device according to claim 10, wherein the deep-drawing device and the cutting device are spaced apart from one another so that a cut-out process takes place at first and the deep drawing follows after further transport of the continuous sheet to the deep-drawing device.

13. A shaping, filling and closing machine having at least one deep-drawing device to create containers open at the top in the form of molded parts, at least one filling device that fills the containers that are open at the top, at least one closing device that closes the open tops of the filled containers, and a transport device that conveys a continuous sheet, which extends along the deep drawing device, the filling device and the closing device, along the deep drawing device, the filling device and the closing device, wherein the shaping, filling and closing machine also has a separation device that separates webs between the continuous sheet and molded parts in such a way that individual containers or units of several containers are cut out of the continuous sheet, wherein at least one deep-drawing device and at least one cutting device according to claim 10 are provided to create containers in the form of molded parts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Further details, features and advantages of the invention result from the description below of examples with reference to the accompanying drawings. The following are shown in the figures:

[0028] FIG. 1: Prior art; results of drawing experiments according to customary methods with a high reshaping ratio with damage in the base area;

[0029] FIG. 2: Schematic representation of an embodiment of the reshaping results with the use of the process as per the invention in a top view;

[0030] FIG. 3: Schematic representation of an embodiment of the reshaping results with the use of the process as per the invention in a view in perspective;

[0031] FIG. 4: Schematic representation of an embodiment of the deep-drawing device as per the invention in a sectional side view;

[0032] FIG. 5: Schematic representation of the process steps as per the invention in a sectional view of the reshaping device;

[0033] FIG. 6: Schematic representation of a shaping, filling and closing machine with an embodiment of the reshaping device as per the invention; and

[0034] FIG. 7: The process flow and operation of the compensation movement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] FIG. 1 shows the prior art with results of drawing experiments according to customary methods with a high reshaping ratio with damage to the base area that arises because of that. A free and largely unhampered movement of material into the clearance is not possible or is only possible when fairly high forces are overcome because of the complete connection of the molded part to the continuous sheet 1 that also exists during the drawing process. The result is excess stresses on the material from pulling; a rupture 3 of the material bond comes about, and the molded part 2 becomes useless because of that. Different variants of ruptures 3 in the base area are shown. Ruptures 3 in the wall of the fiber material can likewise come about, because the greatest stresses specifically arise there when deep drawing fiber materials, always in dependence upon coefficients of friction between the stamp and the fiber material, for instance paperboard.

[0036] FIG. 2 shows a schematic representation of an embodiment of the reshaping results with the use of the process as per the invention in a top view. Molded parts 2 that are still connected to the continuous sheet 1 via a web 5 are formed via deep drawing in the process. The other areas where the cut-to-size section for the molded part 2 was originally connected to the continuous sheet 1 are separated with a stress-easing cut 4. The material of the continuous sheet 1 was pulled into the clearance there without obstruction during the deep-drawing process, so a flawless molded part 2 was able to be formed.

[0037] FIG. 3 shows a schematic representation of an embodiment of the reshaping results with the use of the process as per the invention in a perspective view.

[0038] Molded parts 2 are formed in two rows in the continuous sheet 1 in the process. The molded parts are likewise still connected via a web 5 to the continuous sheet 1 and otherwise separated out of the continuous sheet 1 via stress-easing cuts.

[0039] FIG. 4 shows a schematic representation of an embodiment of the deep-drawing device 6 as per the invention in a sectional side view. The continuous sheet 1 lies in the deep-drawing device 6 in such a way here that it covers the opening of the drawing case 7. The cutting devices 11 that make at least one stress-easing cut 4 in the continuous sheet 1 in collaboration with the opposing blades 12 are provided to obtain a suitable cut-to-size section 2. When the stamp 8 drops into the drawing case 7 during the subsequent deep-drawing process, which is not shown here, the cut-to-size section 2 can be put for shaping into the clearance between the drawing case 7 and the stamp 8 with virtually no obstructions because of that.

[0040] First off, however, the cut-to-size section 2 is fixed in place with the blank holder 9, which presses against the drawing case 7, to the extent that the cut-to-size section 2 is pulled into the clearance against a defined frictional force and without excessive folding. When the molded part has been created, the counter support 13 ejects it in the direction of the stamp 8, which has left the drawing case 7 again in the meanwhile in a direction opposite to the reshaping direction.

[0041] FIG. 5 shows a schematic representation of an embodiment of the method steps as per the invention via sectional views of the reshaping device 6, but without the cutting devices 11, 12 here. They are not directly arranged on the deep-drawing device 6 in the embodiment that is shown, but instead have their effect in an upstream process step. The continuous sheet 1 therefore reaches the reshaping device 6 with stress-easing cuts that have already been made in process step a), but they are not visible in the presentation that was chosen.

[0042] The stamp 8 moves onto the cut-to-size section 2 in the direction of the arrow in process step b). A heater 10 heats the drawing case 7. The actual reshaping process takes place in process step c); the stamp 8 is lowered further in the direction of the arrow, and presses the cut-to-size section 2 into the drawing case 7. The molded part 2 that has now been formed is fixed in terms of its shape via the heat treatment. Finally, the removal from the mold follows, as represented in process step d), in that the counter support 13 ejects the fixed molded part 2 from the mold, the drawing case 7.

[0043] FIG. 6 shows a schematic representation of a shaping, filling and closing machine with an embodiment of the reshaping device 6 as per the invention. The molded part 2 is formed in the process in process step a) with the aid of a deep-drawing device 6 as per the invention. The molded part 2 is designed in the form of packaging material here. It is filled with the goods to be packed via the filling device 30 in process step b). Process step c) follows here, in which a closure is fastened on the molded part 2 via the closing device 31.

[0044] Up to that point, the packaging that has now been formed is still connected to the continuous sheet 1, which ensures easier handling and exact positioning. The packaging has to be separated from the continuous sheet 1, however, to prepare it for delivery. This takes place in a further station, the separation device 32. An individual instance of packaging or, as necessary, grouped packaging therefore exists at this point in process step e) that can be removed and prepared for shipping or for the required follow-up logistical handling.

[0045] The continuous sheet 1 is transported via a transport device 33, and the molded part 2 is therefore conveyed from station to station, as described above.

[0046] FIG. 7 shows the process flow and operation of the passive compensation movement during deep drawing with a starting state a), an intermediate state b) and an end state c), in a side view and top view in each case. The continuous sheet 1 with the cut-to-size sections 2 and later the molded part 2 can be recognized here; the latter is connected to the continuous sheet 1 with the web 5.

[0047] Although the center point M1 of the stress-easing cut 4 coincides before the reshaping with the center point M2 of the (future) molded part 2, this changes during the reshaping when material of the cut-to-size section 2 is pulled into the clearance. Since the molded part is fixed in place on one side in the continuous sheet through the web, the material flow only takes place on one side in the process, so the continuous sheet has to either be free, in order to subsequently move along by the amount of the compensation movement 40 (passive, as shown), or the tools, thus the stamp and the drawing case, have to be moved in such a way that they are carried along with the shift in the center point (active compensation movement, not shown).

LIST OF REFERENCE NUMERALS

[0048] 1 Continuous sheet [0049] 2 Cut-to-size section for the molded part [0050] 2 Molded part [0051] 3 Rupture [0052] 4 Stress-easing cut [0053] 5 Web [0054] 6 Deep-drawing device [0055] 7 Drawing case [0056] 8 Stamp [0057] 9 Blank holder [0058] 10 Heater [0059] 11 Cutting device [0060] 12 Opposing blade [0061] 13 Counter support [0062] 30 Filling device [0063] 31 Closing device [0064] 32 Separation device [0065] 33 Transport device [0066] M1 Center point of the stress-easing stamp [0067] M2 Center point of the molded part [0068] 40 Passive compensation movement