Method and forming device for manufacturing a packaging element

Abstract

Method for manufacturing a packaging element (1) comprising at least the following steps: a) Providing a preform consisting at least partially of a fiber-based packaging material (2) in a forming device (3); b) Holding down the preform (2) by means of a hold-down device (4) in a drawing gap (5) of the forming device (3) with a holding force (29); c) Forming the preform (2) into the packaging element (1) using the forming device (3); and d) Calibrating a sealing edge (6) of the packaging element (1) according to step c) by the hold-down (4) with a calibration force (30) which is greater than the hold-down force (29). Furthermore, a forming device for the production of a packaging element (1) is proposed.

Description

[0001] The present invention relates to a method and a forming device for producing a packaging element. The packaging element is particularly suitable for use as packaging for goods or for producing such packaging.

[0002] The packaging element can be designed, for example, as a tray, bowl, or cup. The packaging element can have a receiving cavity for the product. This receiving cavity can be filled with a product, such as a liquid or a powder, like coffee grounds. After the receiving cavity has been filled with the product, it can be sealed with a seal, particularly a peelable one. The seal can create a gas-tight seal around the product within the receiving cavity. The seal can be, for example, a film. The packaging element can have a sealing rim to which the seal can be attached. The seal can be attached, for example, by welding or adhesive bonding.

[0003] In the production of the packaging element, a preform, for example in the form of a blank or disc, can be formed into the packaging element using a forming device. During forming, the preform is clamped or positioned in a drawing gap between a blank holder and a die. Subsequently, the preform is drawn into the die in the area of ​​what will later become the bottom of the packaging element or the receiving cavity using a punch, allowing material from the preform to flow from the drawing gap into the die.

[0004] Such packaging elements, forming processes, and forming devices for their production are known, for example, from German patent applications DE 10 2022 129 118 A1 and DE 10 2013 107 931 A1. DE 10 2022 129 118 A1 discloses, for example, that different forces can be exerted on the packaging element by means of a hold-down device, for example, depending on the position of the punch. This allows the flow of the packaging element during the formation of at least one shape to be (selectively) varied or controlled. DE 10 2013 107 931 A1 discloses that a pleat holder can be pressed against the packaging element during the forming process using hydraulic or pneumatic pistons. These pistons, and consequently the pressing force of the pleat holder, can be controlled or regulated.

[0005] During forming, a receiving cavity is created in a drawing section of the packaging element, and a circumferential sealing rim forms at one upper end of the packaging element. This circumferential sealing rim can be undefined and / or uneven, particularly due to uneven flow of the preform material from the drawing gap and / or wrinkling. An undefined sealing rim can make it difficult to tightly attach the seal to the rim.

[0006] Starting from this premise, the object of the present invention is to at least partially solve the problems described with reference to the prior art and, in particular, to provide a method for producing a packaging element with which irregularities in the sealing edge can at least be reduced. Furthermore, a forming device for producing a packaging element with which irregularities in the sealing edge can at least be reduced is also to be provided.

[0007] These problems are solved by a method and a forming device according to the features of the independent claims. Further advantageous embodiments are specified in the dependent claims, as well as in the description and, in particular, in the description of the figures. It should be noted that a person skilled in the art can combine individual features in a technologically meaningful way and thereby arrive at further embodiments of the invention.

[0008] This includes a method for manufacturing a packaging element that comprises at least the following steps: a) Providing a preform consisting at least partially of a fiber-based packaging material in a forming device; b) Holding the preform down by means of a hold-down device in a drawing gap of the forming device with a holding force; c) Forming the preform into the packaging element using the forming device; and d) Calibrating a sealing edge of the packaging element according to step c) by the hold-down with a calibration force that is greater than the hold-down force.

[0009] The packaging element is particularly suitable for use as packaging for goods and / or for manufacturing packaging for those goods. The packaging element can be, for example, a tray, a bowl, a pod, or a cup.

[0010] In step a), a preform consisting at least partially of a fiber-based packaging material is provided in a forming device. This provisioning can be carried out, for example, by a conveyor system, particularly an automated one. The preform can be a blank and / or a disc. The preform can be flat and / or have a material thickness of, for example, 0.1 mm to 2 mm. The preform can have a round cross-section. The preform can have a diameter of, for example, 20 mm to 300 mm or an edge length of, for example, 20 mm to 300 mm. The fiber-based packaging material can comprise fibers of plant origin and / or cellulose. The fiber-based packaging material can be, for example, paper, cardboard, or carton. The fiber-based packaging material offers particular advantages with regard to recyclability.The preform can have a coating of at least one other material and / or be impregnated with at least one other material. The coating can, for example, be applied to an inner and / or an outer surface of the preform. The coating can form a barrier layer.

[0011] The forming device can be a deep-drawing press. The forming device can comprise a punch, a die, and / or a blank holder. The blank holder is adjustable, in particular, between a hold-down position and a release position along a blank holder travel path. The blank holder travel path can be straight and / or vertical. The blank holder can be made at least partially of metal. The blank holder can be designed, at least partially, as a plate or a ring. The blank holder has, in particular, a punch opening for the punch, through which the punch can be adjusted, at least partially, into the forming cavity of the die. The blank holder can have a hold-down surface. The hold-down surface is, in particular, designed to be at least partially flat. The blank holder or the hold-down surface of the blank holder limits, at least partially, the drawing gap.The drawing gap extends, in particular, around the at least one forming cavity. The drawing gap can be formed, at least partially, between the blank holder and the die. The blank holder can be made, at least partially, of metal and / or surround the punch. The blank holder can have a punch opening for the punch. The blank holder can be electrically, hydraulically, or pneumatically adjustable between the hold-down position and the release position. The blank holder is, in particular, adjustable relative to the die and / or independently of the punch. The die can have at least one forming cavity. The die is, in particular, made, at least partially, of metal. The die or the at least one forming cavity can form, at least partially, a negative of a shape or an outer shape of the packaging element (to be manufactured and / or formed).The at least one forming cavity can be designed as an opening, a drawing opening, and / or a trough. The at least one forming cavity can be located in an upper outer surface of the die. The upper outer surface of the die can be flat.

[0012] In step b), following step a), the preform is held in place by a blank holder within a drawing gap of the forming device using a holding force. For this purpose, the blank holder is moved into the holding position. In this position, the preform is clamped in the drawing gap, specifically between the blank holder and the die. In this position, the drawing gap (particularly in a vertical direction) can have a gap width that corresponds, in particular, (essentially) to the material thickness of the preform. The gap width can, for example, be from 0.1 mm to 2 mm. The blank holder is pressed onto the preform with a holding force that allows the preform to flow and / or slide out of the drawing gap towards the forming cavity of the die. The holding force can, for example, be from 1 N [Newton] to 200 N.The holding force can be generated using a pressing device of the forming device.

[0013] In step c), the preform is formed into the packaging element using the forming device. The forming process takes place while the preform is held in the drawing gap by the blank holder with a clamping force. The clamping force can be varied during the forming of the preform, for example, depending on the position of the punch. This allows the flow and / or slippage during the forming of the preform to be (specifically) varied or controlled. For forming the preform, the punch can be adjusted to a forming position, in particular into the at least one forming cavity of the die. During forming, the punch draws the preform, in particular partially, into the at least one forming cavity of the die. The forming process creates, in particular, a receiving cavity for the packaging element to hold the product. During forming, the preform can be transformed into the packaging element by plastic deformation or deep-drawn.The punch can be designed, for example, as a male die, deep-drawing die, or embossing die. The shape of the punch can be at least partially adapted to the shape of at least one forming cavity. The punch can be electrically, hydraulically, and / or pneumatically driven or adjustable, for example, by means of a punch drive. The punch is adjustable relative to the die, particularly along a punch travel path and / or between a starting position and the forming position. The punch travel path can be straight and / or vertical. During forming, a sealing edge of the packaging element is created, particularly from an edge of the preform, in the drawing gap. This sealing edge can, for example, have a sealing edge width of 0.5 mm to 10 mm. The sealing edge width can be (essentially) constant along the sealing edge.A seal for closing the receiving cavity of the packaging element can be attached to the sealing edge, for example by means of an adhesive bond and / or a weld. The seal can, for example, be in the form of a film. The receiving cavity can be sealed by the seal in a fluid-tight, gas-tight, and / or airtight manner.

[0014] In step d), the sealing edge of the packaging element is calibrated by the blank holder with a calibration force greater than the holding force after step c). Step d) is performed, in particular, only after the preform has been completely formed in step c) and / or after the punch has been completely moved into the forming position in step c). During calibration, the blank holder is pressed against the sealing edge of the packaging element in the drawing gap with the calibration force, and / or, in particular, the sealing edge of the packaging element is clamped in the drawing gap, especially between the blank holder and the die, with the calibration force. The calibration force is greater than the holding force, in particular the maximum force, during step c).Calibration in step d) can be performed with a calibration force that is (particularly significantly) greater than a holding force that still allows sufficient flow and / or slippage of the preform from the drawing gap in step c). In other words, calibration in step d) can be performed with a calibration force that is (particularly significantly) greater than the maximum permissible holding force in step c). The maximum permissible holding force in step c) is a holding force that, if exceeded, causes cracks in the packaging element during the forming process. The calibration force can be generated by the forming machine's pressure device.

[0015] Calibrating the sealing edge with the calibration force allows wrinkles that may have formed in the sealing edge of the packaging element during the forming process in step c) to be at least partially or completely smoothed out. This prevents leaks when attaching the seal to the sealing edge.

[0016] The calibration force can be at least twice as large as the maximum holding force (in step c). Preferably, the calibration force can be at least ten, one hundred, or one thousand times as large as the maximum holding force (in step c).

[0017] The calibration force can be at least 0.5 kN (kilonewtons). Preferably, the calibration force can be at least 1 kN, at least 5 kN, at least 10 kN, at least 50 kN, or at least 100 kN. In particular, the calibration force can be up to 120 kN. For example, the calibration force can be 0.5 kN to 120 kN, 1 kN to 120 kN, 5 kN to 120 kN, 10 kN to 120 kN, 50 kN to 120 kN, or 100 kN to 120 kN.

[0018] Calibration can be performed with a calibration duration of 1 second to 10 seconds.

[0019] Following another aspect, a forming device for manufacturing a packaging element is also proposed, which has at least the following features: - a stamp for transforming a preform into the packaging element; - a hold-down device for holding the preform in place with a holding force in a drawing gap during forming; - a pressure device for the hold-down device; - a control system for controlling the pressure device, which is designed and intended to calibrate a sealing edge of the packaging element by the hold-down device with a calibration force greater than the hold-down force after the preform has been formed into the packaging element.

[0020] The forming device and / or the control system can be used to carry out the procedure described here, or can be set up and / or intended to carry out the procedure described here.

[0021] The clamping device can be electric, hydraulic, and / or pneumatic. The clamping device allows the hold-down clamp to be adjusted along its travel path, particularly between the release position and the clamping position. The clamping device is specifically responsible for generating the clamping force and / or the calibration force of the hold-down clamp.

[0022] The forming device may include a device for variable design (distance) of the drawing gap during forming. The forming device may also include a device for setting a gap width of the drawing gap during forming. The gap width may be dimensioned, in particular, in a vertical direction and / or parallel to the punch travel path.

[0023] The control system is, in particular, an electronic control system. The control system may include at least one microprocessor. The control system allows, in particular, the adjustment of the blank holder along its travel path, the magnitude of the blank holder force, and / or the magnitude of the calibration force. The control system may be configured and / or intended for controlling the forming device. Specifically, steps a), b), c), and / or d) of the process may be at least partially (especially automatically) controllable or executable by the control system. The control system may be connected to the pressing device and / or the punch drive via data transmission.

[0024] The pressing device can have a shaft with at least one eccentric section. The shaft can be made at least partially of metal. The shaft can be rotatable about an axis of rotation by means of a drive, for example, an electric motor. The shaft can be connected to a rotor of the drive, for example, at a longitudinal end of the shaft. The connection between the shaft and the rotor can be made via a coupling. The drive can be controlled by the control system of the forming device. The shaft can have a wavelength of, for example, 100 mm to 1,000 mm (in particular parallel to the axis of rotation). The shaft can have at least one bearing section. The at least one bearing section can have a bearing section diameter of, for example, 10 mm to 100 mm (in particular orthogonal to the axis of rotation). The shaft can be connected to the at least one bearing section in at least one rotary support bearing of the forming device.The forming device's machine frame must be rotatably mounted. The at least one rotary support bearing can, for example, be a roller bearing. The shaft and / or the at least one rotary support bearing can be fixed to the forming device's machine frame.

[0025] The at least one eccentric section can have a circular cross-section (particularly perpendicular to the axis of rotation), the center of which lies outside the axis of rotation of the shaft. The at least one eccentric section can have an eccentric section diameter of, for example, 15 mm to 150 mm. The at least one eccentric section allows a rotational movement of the shaft about the axis of rotation to be converted into a translational movement of the blank holder along its travel path. The further the at least one eccentric section of the shaft is rotated towards the die, particularly by means of the control and / or the drive, the further the blank holder can be moved towards the die and / or into the blanking position.The further at least one eccentric section of the shaft is rotated towards the die, particularly by means of the control and / or the drive, the greater the holding force with which the blank holder is pressed onto the preform, and / or the greater the calibration force with which the blank holder is pressed onto the sealing edge of the packaging element. Particularly high calibration forces can be generated using the shaft.

[0026] The shaft can be rotatable about an axis of rotation that runs orthogonally to the blank holder's travel path. The axis of rotation can extend horizontally and / or the blank holder's travel path vertically. This reduces the installation space required for the forming device.

[0027] At least one eccentric section can be arranged in a rotary bearing of the hold-down device. This rotary bearing can, for example, be a cam bearing or a roller cam bearing.

[0028] The shaft can extend through the punch. In particular, the shaft can extend through an opening formed in the punch. The opening is specifically designed such that the punch can be adjusted along its travel path by means of the punch drive, while the shaft extends through the opening in the punch. The opening can, for example, be designed as an elongated slot.

[0029] It should be noted that the advantages and features described in connection with the process are also applicable and transferable to the forming device. Furthermore, the advantages and features described in connection with the forming device are also applicable and transferable to the process.

[0030] The invention and its technical context are explained in more detail below with reference to the figures. The figures show a preferred embodiment, to which the invention is not limited. It should be noted in particular that the figures, and especially the size relationships shown in the figures, are only schematic. The following are shown by way of example and schematically: Fig. 1: a forming device with a hold-down in a release position and a punch in a starting position in a longitudinal section; Fig. 2: the forming device with the hold-down in a hold-down position and the punch in the starting position in the longitudinal section; Fig. 3: the forming device with the hold-down device in the hold-down position and the punch in a forming position in the longitudinal section; Fig. 4: the forming device with the hold-down device in the hold-down position and the punch in the starting position in the longitudinal section; Fig. 5: the forming device in the longitudinal section; and Fig. 6: A shaft of a pressing device of the forming device in a perspective view.

[0031] Fig. Figure 1 shows a forming device 3 in a longitudinal section. The forming device 3 comprises a punch 7, a blank holder 4, and a die 18 with a forming cavity 19. The punch 7 extends through a punch opening 20 of the blank holder 4 and is located in Fig. 1 in a starting position 21. The stamp 7 is between the starting position 21 and one in Fig. 3 forming position 22 shown along a vertical punch travel path 23 with a in Fig. The punch drive 27 shown in section 5 is adjustable. The hold-down device 4 is located in Fig. 1 in a release position 24. The hold-down device 4 is located between the release position 24 and one in the Fig. 2 to 4 shown hold-down position 25 with a in Fig. The pressure device 8 shown in Figure 5 is adjustable along a vertical blank holder travel path 26. If the punch 7 is in the starting position 21 and the blank holder 4 is in the release position 24, a preform 2 can be provided in the forming device 3 in one step. The preform 2 is a blank. The preform 2 can be provided by a conveying device (not shown here). The preform 2 was in Fig. 1 arranged on an upper outer surface 28 of the die 18.

[0032] Fig. Figure 2 shows the forming device 3 after the hold-down device 4 has been removed from the forming device in step b). Fig. The release position 24 shown in Figure 1 was moved to the hold-down position 25. In the hold-down position 25, the hold-down device 4 can hold the preform 2 in a drawing gap 5 with a holding force 29 in step b). The drawing gap 5 is formed between the hold-down device 4 and the upper outer surface 28 of the die 18. The punch 7 is located in Fig. 2 remain in the starting position 21

[0033] Fig. Figure 3 shows the forming device 3 after the punch 2 has been removed from the die in step c). Fig. The starting position 21 shown in section 2 was moved along the punch travel path 23 to the forming position 22. In this process, the punch 7 pulls the [part] into Fig. 1 and Fig. The preform 2 shown in Figure 2 is placed into the forming cavity 19 of the die 18, so that the preform 2 is formed into a cup-shaped packaging element 1. During the forming of the preform 2 into the packaging element 1, the blank holder 4 holds the preform 2 in the drawing gap 5 with the blanking force 29, so that a Fig. The edge 14 of the preform 2 shown in Figure 2 can be partially drawn out of the drawing slot 5 into the forming cavity 19 of the die 18. The edge 14 remaining in the drawing slot 5 after the preform 2 has been formed into the packaging element 1 forms a sealing edge 6 of the packaging element 1.

[0034] Fig. Figure 4 shows the forming device 3 after step c) in step d) during the calibration of the sealing edge 6 of the packaging element 1. During the calibration of the sealing edge 6, the hold-down device 4 presses the sealing edge 6 in the drawing gap 5 onto the upper outer surface 28 of the die 18 with a calibration force 30, which is greater than that in Fig. 2 and Fig. 3. Holding force 29 shown. This at least partially smooths and / or removes wrinkles that form in the sealing edge 6 during forming in step c). After calibrating the sealing edge 6, the punch 7 is returned to the Fig. 1 and Fig. 2 shown starting position 21 and the hold-down device 4 from the hold-down position 25 back into the in Fig. The release position 24 shown is adjusted. This allows the packaging element 1 to be removed from the forming device 3.

[0035] In Fig. Figure 5 shows the forming device 3 in a longitudinal section with a higher level of detail. The blank holder 4 is adjustable along the blank holder travel path 26 with the pressure device 8. The pressure device 8 comprises a shaft 10, which can be rotated about a rotary axis 13 by means of an electric motor 17. The shaft 10 is connected to a rotor 37 of the electric motor 17 via a coupling 36. The electric motor 17 can be controlled by a control unit 9 of the forming device 3. The shaft 10 has a Fig. 6 shown first storage section 31 and one in Fig. The second bearing section 32 shown in Figure 6. The shaft 10 is rotatably mounted with the first bearing section 31 in a first rotary support bearing 33 of the forming device 3 and with the second bearing section 32 in a second rotary support bearing 34 of the forming device 3. The rotary support bearings 33, 34 can, for example, be roller bearings. The rotary support bearings 33, 34 are fixedly attached to a machine frame 35 of the forming device 3, which is only partially shown here. The shaft 10 has a Fig. 6 shown first eccentric section 11 and one in Fig. The second eccentric section 12 is shown in Figure 6. The eccentric sections 11 and 12 each have a circular cross-section (orthogonal to the axis of rotation 13), the center of which lies outside the axis of rotation 13. The first eccentric section 11 is arranged in a first rotary bearing 15 of the hold-down device 4, and the second eccentric section 12 in a second rotary bearing 16 of the hold-down device 4, so that a rotational movement of the shaft 10 about the axis of rotation 13 can be converted into a translational movement of the hold-down device 4 along the hold-down device travel path 26. The rotary bearings 15 and 16 can, for example, be cam bearings or roller cam bearings. The further the eccentric sections 11, 12 of the shaft 10 are rotated towards the die 18, in particular by means of the control 9 and / or the electric motor 17, the further the hold-down 4 is moved towards the die 18 and / or the greater the force with which the hold-down 4 presses against the workpiece in the drawing gap 5. Fig. 1 and Fig. The preform shown in 2 is pressed onto the packaging element 1.

[0036] Wave 10 extends with a in Fig. The connecting section 38 shown in 6 is connected by an opening 39 formed in the punch 7. The connecting section 38 connects the Fig. The eccentric sections 11 and 12 of the shaft 10 are shown in Figure 6. The opening 39 is designed such that the punch 7 can be adjusted along the punch travel path 23 by means of the punch drive 27. The opening 39 is designed here as an elongated slot. The punch travel path 23 of the punch 7 is orthogonal to the axis of rotation 13 of the shaft 10. The punch travel path 23 of the punch 7 is vertical, and the axis of rotation 13 of the shaft 10 is horizontal.

[0037] Fig.Figure 6 shows the shaft 10 in a perspective view. The shaft 10 has a wavelength 40 (parallel to the axis of rotation 13). The bearing sections 31, 32 each have a bearing section diameter 41 and the eccentric sections 11, 12 each have an eccentric section diameter 42.

[0038] The invention makes it at least possible to reduce irregularities in the seal edge 6. Reference symbol list 1 packaging element 2 Preform 3. Converter 4 hold-down devices 5 Draw gap 6 Seal edge 7 stamps 8. Pressing device 9 Control 10 wave 11 first eccentric section 12 second eccentric section 13. Axis of rotation 14 Rand 15 first pivot bearing 16 second pivot bearing 17 Electric motor 18 die 19 Forming cavity 20 Stamp opening 21 Starting position 22 Forming position 23 Stamp travel path 24 Release position 25 Hold-down position 26 Hold-down travel 27 Stamp drive 28 upper outer surface 29 Holding force 30 Calibration force 31 first camp section 32 second camp section 33 first rotary support bearing 34 second rotary support bearing 35 machine frame 36 Clutch 37 Rotor 38 Connecting section 39 Opening 40 a wavelength 41 Bearing section diameter 42 eccentric section diameter

Claims

[1] Method for producing a packaging element (1), comprising at least the following steps: a) providing a preform (2) consisting at least partially of a fiber-based packaging material in a forming device (3); b) holding down the preform (2) by means of a hold-down device (4) in a drawing gap (5) of the forming device (3) with a hold-down force (29); c) forming the preform (2) into the packaging element (1) by means of the forming device (3); and d) Calibrating a sealing edge (6) of the packaging element (1) after step c) by the hold-down device (4) with a calibration force (30) which is greater than the hold-down force (29). [2] Method according to claim 1, wherein the calibration force (30) is at least twice as large as the hold-down force (29). [3] Method according to one of the preceding claims, wherein the calibration force (30) is at least 0.5 kN. [4] Method according to one of the preceding claims, wherein the calibration is carried out with a calibration duration of 1 second to 10 seconds. [5] Forming device (3) for producing a packaging element (1) which consists at least partially of a fiber-based packaging material, at least comprising: - a stamp (7) for forming a preform (2) into the packaging element (1); - a hold-down device (4) for holding down the preform (2) with a hold-down force (29) in a drawing gap (5) during forming; - a pressing device (8) for the hold-down device (4); - a controller (9) for controlling the pressing device (8), which is designed and provided to calibrate a sealing edge (6) of the packaging element (1) by the hold-down device (4) with a calibration force (30) which is greater than the hold-down force (29) after the preform (2) has been formed into the packaging element (1). [6] Forming device (3) according to claim 5, wherein the pressing device (8) has a shaft (10) with at least one eccentric section (11, 12). [7] Forming device (3) according to claim 6, wherein the shaft (10) is rotatable about an axis of rotation (13) which is orthogonal to a hold-down travel path (26) of the hold-down device (4). [8] Forming device (3) according to claim 6 or 7, wherein the at least one eccentric section (11, 12) is arranged in at least one rotary bearing (15, 16) of the hold-down device (4). [9] Forming device (3) according to one of claims 6 to 8, wherein the shaft (10) extends through the punch (7). [10] Forming device (3) according to one of claims 5 to 9, wherein the pressing device (8) comprises an electric motor (17).

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