CUTTING DEVICE AND METHOD FOR MANUFACTURING A CUTTING PUNCH

Abstract

The disclosure relates to a cutting device which is adapted for cutting substantially round packaging corners from a film web, wherein the cutting device has at least one cutting tool comprising a cutting punch which has at its outside at least one concavity provided for forming a cutting edge of the cutting punch. According to the disclosure, the cutting edge has a cutting contour extending both transversely and longitudinally along the cutting punch. The disclosure further relates to a method for manufacturing a cutting punch.

Claims

1. A cutting device adapted for cutting substantially round packaging corners from a film web, the cutting device having at least one cutting tool comprising a cutting punch which has at its outside at least one concavity provided for forming a cutting edge of the cutting punch, wherein the cutting edge has a cutting contour extending both in transverse and in longitudinal extension of the cutting punch.

2. The cutting device according to claim 1, wherein the cutting edge projected in a cutting plane at least partially has a star-shaped cutting contour.

3. The cutting device according to claim 1, wherein the cutting punch has a plurality of tips which are configured both in transverse and in longitudinal extension of the cutting punch.

4. The cutting device according to claim 3, wherein along the cutting contour of the cutting edge the tips formed in longitudinal extension of the cutting punch correspond to the tips formed in transverse extension of the cutting punch.

5. The cutting device according to claim 3, wherein along the cutting contour of the cutting edge the tip formed in longitudinal extension of the cutting punch are configured between the tips formed in transverse extension of the cutting punch.

6. The cutting device according to claim 1, wherein the cutting punch has at least one depression which, superimposed with the first concavity, forms the cutting edge.

7. The cutting device according to claim 6, wherein the depression is cone-shaped.

8. The cutting device according to claim 6, wherein the depression is at least partially in the form of a truncated cone with respect to a longitudinal axis of the cutting punch.

9. The cutting device according to claim 1, wherein the cutting punch is formed in one piece.

10. The cutting device according to claim 1, wherein the cutting punch has four concavities on its outside.

11. A thermoforming packaging machine comprising, in a transport direction, a forming station, a sealing station, a transverse cutting station and a longitudinal cutting station, wherein the transverse cutting station comprises at least one cutting device according to claim 1.

12. A method for manufacturing a cutting punch, wherein at least one concavity is produced on an outer side of a workpiece blank and wherein a depression is produced on another side of the workpiece blank such that the depression, superimposed on the concavity, forms a cutting edge of the cutting punch with a cutting contour extending both in the transverse and in the longitudinal extent of the cutting punch.

13. The method according to claim 12, wherein a cylindrical milling tool is used to produce the concavity and an at least partially conical, parabolic or cylindrical milling tool is used to produce the depression.

14. The method according to claim 13, wherein the milling tool for producing the concavity and the milling tool for producing the depression produce the cutting edge by means of an at least temporarily simultaneously controlled feed movement or are used in successive separate working steps.

15. The method according to claim 12, wherein the cutting punch is cured at least along its cutting edge by means of a thermal method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In the following, preferred embodiments of the disclosure are explained in more detail with reference to drawings.

[0031] FIG. 1 shows a perspective view of a thermoforming packaging machine;

[0032] FIGS. 2A to 2D show a cutting device according to the disclosure during various operating phases;

[0033] FIGS. 3A to 3G show a cutting punch of the cutting device according to the disclosure during cutting of a film web; and

[0034] FIG. 4 shows a cutting punch with a three-dimensional cutting contour according to a variant.

[0035] Similar components are identified by the same reference signs throughout the Figures.

DETAILED DESCRIPTION

[0036] FIG. 1 shows a perspective view of an intermittently operating thermoforming packaging machine 1. This thermoforming packaging machine 1 has a forming station 2, a sealing station 3, a transverse cutting device 4 and a longitudinal cutting device 5, which are arranged in this order in a transport direction R on a machine frame 6. On the input side, a feed roller 7 is located on the machine frame 6, from which a lower film 8 is drawn off. Furthermore, the thermoforming packaging machine 1 has a transport chain 11 which grips the lower sheet 8 and transports it further in the transport direction R per main working cycle, in particular transport chains or clamp chains 11 arranged on both sides.

[0037] In the embodiment shown, the forming station 2 is configured as a deep-drawing station in which troughs are formed in the lower film 8 by deep-drawing, for example by means of compressed air and/or vacuum. The forming station 2 can be configured such that several troughs are formed next to each other in the direction perpendicular to the transport direction R. A filling path 12 is provided downstream of the forming station 2 in the transport direction R, in which the troughs formed in the lower film 8 are filled with products.

[0038] The sealing station 3 has a hermetically sealable chamber 3a in which the atmosphere in the troughs can be replaced, e.g., evacuated and/or by gas purging, with an exchange gas or with a gas mixture before sealing with the upper film 10 dispensed from an upper film receptacle 9.

[0039] The transverse cutting device 4 is adapted to cut a film web F fed into it, consisting of the lower film 8 and the upper film 10 sealed therewith, in a direction transverse to the transport direction R between adjacent troughs. The transverse cutting device 4 operates such that the lower film 8 is not cut across its entire width, but is not cut through at least in an edge region. This allows controlled onward transport through the transport chain 11.

[0040] The longitudinal cutting device 5 can be configured as a knife arrangement with which the film web F, i.e., the lower film 8 and the upper film 10, are cut between adjacent troughs and at the lateral edge of the lower film 8 in the transport direction R so that separated packages are present downstream of the longitudinal cutting device 5.

[0041] The right and left transport chains 11 of the thermoforming packaging machine 1, which grip the lower web 8 on both sides, are each guided in a chain guide 13. These chain guides 13 are each protected from the outside by a side panel 14 of the thermoforming packaging machine 1 and, if necessary, fastened to the side panel 14. The side paneling 14 can be a sheet metal part.

[0042] The thermoforming packaging machine 1 furthermore has a control system 19. This has the task of controlling and monitoring the processes running in the thermoforming packaging machine 1. A display device 20 with operating elements 21 is used to visualize or influence the process sequences in the thermoforming packaging machine 1 for or by an operator.

[0043] FIGS. 2A to 2D show a cutting device 15 belonging to the transverse cutting device 4 of FIG. 1.

[0044] The cutting device 15 comprises a cutting tool 16 and a hold-down device 17 positioned above it. FIG. 2A shows the cutting device 15 in an open position. The cutting tool 16 and/or the hold-down device 17 are mounted in a height-adjustable manner. According to FIG. 2a, the cutting tool 16 has several spaced-apart cutting punches 18. The respective cutting punches 18 are adapted for cutting round packaging corners from the film web F.

[0045] In FIG. 2A, cutting knives 22 are mounted between the respective cutting punches 18. The cutting knives 22 can cut the film web F in a direction transverse to the transport direction R between adjacent troughs.

[0046] Corresponding to a horizontally projected geometry of the cutting punches 18 and the cutting knives 22 positioned between them, the hold-down device 17 has a corresponding die 23. According to FIG. 2A, the die 23 is equipped with star-shaped openings 24 as piercing openings for the cutting punches 18, into which, as shown in FIGS. 2B to 2D, the cutting punches 18 can immerse in order to produce round packaging corners in the web F.

[0047] The cutting punches 18 mounted on the cutting tool 16 in FIG. 2A each have a cutting edge 25 which forms a cutting contour 26 extending both transversely and longitudinally along the cutting punch 18. The cutting contour 26 is thus three-dimensional with respect to a cutting plane E (see FIG. 3A) in which the film web F is guided.

[0048] How the cutting punches 18 and the cutting knives 22 positioned therebetween cooperate with the die 23 formed within the hold-down device 17 is illustrated with reference to FIGS. 2B to 2D.

[0049] FIG. 2B shows that tips 27 formed on the respective cutting punches 18 first dip into the die 23 formed on the hold-down device 17 when the cutting device 15 closes. This ensures that the entire cutting edge 25 does not penetrate the film web F at once during the cutting process (see FIG. 3A), but that the tips 27 are to a certain extent first punctured into the film web F. In the process, the tips 27 cut through the film web F further and further with increasing penetration depth until a complete star-shaped cutout (see FIG. 3G) is produced. Because the tips 27 of the respective cutting punches 18 penetrate into the film web F with increasing penetration depth, i.e., with increasing cross-section, the respective cutting edge 25 of the cutting punches 18 can cut through the film web F with a reduced cutting force.

[0050] FIG. 2B also shows that, when the cutting device 15 is closed, the tips 27 of the cutting punches 18 first cut out the round packaging corners from the film web F. Subsequently, as shown in FIG. 2C, the cutting knives 22 positioned between the punches 18 immerse through the die 23 formed in the hold-down device 17, creating cross-sections between the round packaging corners already cut out.

[0051] In FIG. 2D, the cutting punches 18 and the cutting knives 22 positioned between them are maximally dipped into the die 23 in the hold-down device 17 so that a complete cutout in the film web F is achieved.

[0052] The outer cutting punches 18 shown on the cutting tool 16 in FIGS. 2A to 2D have a blade 28 by means of which the film web F can be cut on its outsides.

[0053] FIGS. 2A to 2D show that the respective cutting punch 18 has a dome-like cutting head. This allows the cutting punch 18 to penetrate the film web F with the tips 27 in front with little force, resulting in a cutting path that is drawn into the film web F. This results in low stresses forming within the film F during the cutting process, which enables a more precise cutout of the film.

[0054] FIGS. 3A to 3G show how the cutting punch 18 penetrates further and further into the film web F with its cutting edge 25 as the penetration depth increases. The film web F is positioned within the cutting plane E in FIG. 3A. In this cutting plane E, the film web F is held between the cutting tool 16 and the hold-down device 17 positioned above it for the cutting process.

[0055] FIG. 3A shows that the cutting punch 18 already punctures the film web F with its tips 27. The tips 27 can penetrate the film web F with comparatively little force. FIG. 3A shows that the cutting edge 25 of the cutting punch 18 between the tips 27 is for the most part still positioned below the film web F. With increasing penetration of the cutting punch 18 into the film web F, the cutting edge 25 cuts through the film web F more and more, resulting in a complete cutout. This is shown in FIGS. 3B to 3G.

[0056] A depression 29 is formed in the cutting punch 18 of FIG. 3A. Together with a concavity 30 formed on the circumference of the cutting punch 18, the depression 29 forms the curved cutting edge 25.

[0057] According to FIG. 3A, the depression 29 is cone-shaped. A conical milling tool could be used to produce the depression 29 so that the depression 29 is at least partially in the form of a truncated cone with respect to a longitudinal axis of the cutting punch 18.

[0058] The concavities 30 formed on the outside of the cutting punch 18 in FIG. 3A together with the depression 29 form a dome-like cutting head whose tips 27 penetrate the film web F like knife tips during the cutting process. The concavities 30 can be produced by means of a cylindrical milling tool.

[0059] FIG. 3B shows the tips 27 with increasing penetration depth compared to FIG. 3a. In view of FIGS. 3A to 3G, it is shown that the cutting edge 25 increasingly cuts through the film web F as the cutting punch 18 moves into the die 23 (see FIGS. 2A to 2D). The cutting edge 25, which is increasingly pulled through the film web F, is thus pulled through the film web F like a knife until, as shown in FIG. 3G, the tips 27 are positioned completely above the film web F, whereby the round packaging corners are completely cut out.

[0060] FIG. 4 shows a cutting punch 18′ according to the embodiment in various views. The cutting punch 18′ of FIG. 4 has a cutting edge 25′ providing tips 27′ formed in longitudinal extension of the cutting punch 18′, which are located between tips 27″ formed in transverse extension of the cutting punch 18′. Seen in a horizontal projection plane, the cutting punch 18′ thus has the star shape shown in FIG. 4, i.e., a star-shaped cutting line course, as can also be produced by means of the cutting punch 18 shown in FIGS. 3A to 3G.

[0061] The cutting punch 18, 18′ used in the disclosure has a cutting edge 25, 25′ with a three-dimensional cutting contour 26, 26′, by means of which a cutting path can be produced which gradually moves with increasing penetration depth so that the transverse cutting device 4 can operate under comparatively low cutting forces in order to produce round packaging corners. The three-dimensional, curved cutting contour 26, 26′ can be used to prevent the film cutouts produced from folding away, so that an overall precise cutout is achieved. The production of a cutting punch 18, 18′ used on the cutting device 15 according to the disclosure is possible at low cost by means of a milling machine with single-axis operation. The cutting punches 18, 18′ according to the disclosure improve a precise separation of packages from the film web F, can be manufactured economically as such and enable an efficient operation of the transverse cutting device 4.