Adjustment of liquid food holding package making machine

Abstract

A control device (230) operates a machine (2) for producing packages (10) containing a liquid food product. The machine is operated to move an inner tool (21) projecting radially from a rotatable member (22) to a processing position (II), position an outer tool (25) at the processing position (II) to surround an end of the inner tool (21), and operate the outer tool (25) to provide a top portion on an end of a package body (11) disposed on the inner tool (21). The control device (230) executes the monitoring procedure by determining at least one parameter value indicative of a lateral force acting on the inner tool (21) at the processing position (II) while the outer tool (25) is positioned to surround the end of the inner tool (21), and by selectively adjusting the relative positions of the inner and outer tools (21, 25) based on the parameter value.

Description

[Technical Field]

[0001] The present disclosure relates to the manufacture of packages for holding liquid food products, and in particular to techniques for controlling machines for manufacturing such packages. [Background technology]

[0002] In the food industry, it is common to package liquid foods in packages made of a paper-based laminate comprising a core layer of paper or paperboard and one or more barrier layers of, for example, plastic.

[0003] One common type of package is produced by forming a tubular blank ("sleeve") from the paper-based laminate described above and sealing one end of the sleeve with a top portion of plastic material. Conventionally, the top portion is formed directly on the end of the sleeve by injection molding. The top portion has a neck portion defining a spout and is sealed with a cap and / or foil. The cap and / or foil may be provided by injection molding or in a separate attachment step. The package is then transported to a subsequent filling station, where the liquid product is filled through the opposite open end of the package. After filling, the open end of the package is folded over and sealed. The applicant sells this type of package under the trademark Tetra Top®.

[0004] The sleeve is placed on the arm of the mandrel wheel, and the arm is rotated to place the sleeve in the injection molding apparatus. While the sleeve is held on the arm, the injection molding apparatus is positioned to surround the end of the sleeve and operated to form a top portion on the end.

[0005] Industrial production and packaging of liquid foods is automated, requiring sophisticated process control of machinery to achieve high-volume production. Safe and reliable operation is crucial, as operational failures and resulting production stoppages can have a significant impact on production costs and product quality. For example, it is crucial to avoid operational failures that could damage machinery or result in the rejection of mass-produced packaging.

[0006] The top forming operation is vulnerable to mishandling, as incorrect attachment of the top to the sleeve can result in a package that is prone to leaking liquid food or that is not sealed. Such packages must be discarded. Improper attachment can also cause consequential problems in downstream production, such as leaking food that must be cleaned at the filling station.

[0007] This problem is common when manufacturing packages for containing liquid foods, where a body portion needs to have a top portion. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object to at least partially overcome one or more of the above identified limitations of the prior art.

[0009] One such object is to provide a technique that improves the ability to form a top portion on a body portion when manufacturing a package for holding a liquid food product.

[0010] One or more of these objects, as well as further objects that may become apparent from the following description, are at least partly achieved by a computer-implemented method, a computer-readable medium, and a control device for operating a machine for producing packages for holding liquid food according to the independent claims, embodiments of which are defined by the dependent claims.

[0011] A first aspect relates to a computer-implemented method for operating a machine for manufacturing packages for containing a liquid food product. The machine includes an inner tool and an outer tool. The inner tool protrudes radially from a rotatable member operable to move the inner tool from a loading position to a processing position, and the outer tool is operable to be positioned to surround an end of the inner tool. The method includes a manufacturing sequence including: operating the rotatable member to position the inner tool in the loading position; placing a package body on the inner tool at the loading position; operating the rotatable member to move the inner tool together with the package body from the loading position to the processing position; positioning the outer tool to surround an end of the inner tool, thereby surrounding an end of the package body; and operating the outer tool to provide a top portion on the end of the package body, thereby manufacturing the package. The method further includes a monitoring procedure including the steps of determining, based on the measurement signal, at least one parameter value indicative of the lateral force acting on the inner tool at the machining position while the outer tool is positioned to surround the end of the inner tool, and selectively adjusting the relative position between the inner tool and the outer tool based on the at least one parameter value.

[0012] Through the monitoring procedure, the method of the first aspect provides a technique for quantifying and correcting misalignments between the inner and outer tools that may result in poor machine performance in terms of the quality of the resulting package. Misalignments may occur, for example, as a result of errors in the control of the rotatable members and / or the outer tool, shifts in the position of the inner and / or outer tool, mechanical deformation of the inner and / or outer tool, etc. The monitoring procedure may be performed separately from the manufacturing procedure or during the manufacturing procedure. If performed prior to the manufacturing procedure, the package body may or may not be positioned around the inner tool during the monitoring procedure. If performed during the manufacturing procedure, the actual performance of the machine may be evaluated while the outer tool is being operated to provide the top portion to the body. Thus, the method allows for corrective action to be taken during ongoing manufacturing, preventing production stoppages as a result of misalignments between the inner and outer tools.

[0013] The parameter value may be any measurement proportional to or otherwise representative of the lateral force on the inner tool, for example the parameter value may be a lateral force value from a force sensor, a torque value from a torque sensor, a power or drive current value of a drive unit for a rotatable member, a strain value from a strain sensor, etc.

[0014] The inner tool projects radially from the rotatable member and therefore has a longitudinal extent from the rotatable member to a distal end, which is the end that is surrounded by the outer tool in the processing position. As used herein, lateral force refers to the total component acting on the inner tool and directed perpendicular to the longitudinal extent of the inner tool.

[0015] As used herein, the term "selectively adjust" means that the relative position between the inner tool and the outer tool is adjusted, subject to meeting predefined criteria based on at least one parameter value.

[0016] As used herein, "liquid food" refers to any food that is non-solid, semi-liquid, or pourable at room temperature, such as beverages like water, fruit juice, wine, beer, soda, etc., dairy products, sauces, oils, cream, custard, soup, paste, etc., or liquid solid foods like pulses, fruit, tomatoes, stews, etc.

[0017] As used herein, "package" refers to any package or container suitable for holding a liquid food product, including, but not limited to, containers formed from cardboard or paper-based laminates, containers made of or containing plastic materials, and the like.

[0018] A second aspect relates to a computer-readable medium comprising program instructions configured, when executed by a processor circuit, to cause the processor circuit to perform the method of the first aspect or any of its embodiments.

[0019] A third aspect relates to a control device configured to perform the method of the first aspect or any of its embodiments, the control device comprising a signal interface configured to receive the measurement signals and to provide control signals for operating a machine.

[0020] The second and third aspects share technical advantages with the first aspect. [Means for solving the problem]

[0021] Further objects, features, embodiments, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying schematic drawings. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating a sequence of processing stations in an example production line for producing packages containing liquid food products. [Figure 2A] 2 is a side view of an example of a package produced by the top forming station of the manufacturing line of FIG. 1. [Figure 2B] 2B is a cross-sectional view of the shoulder portion of the package of FIG. 2A. [Figure 3] FIG. 10 is a side view of a top forming station according to a detailed embodiment. [Figure 4A] 4 is a cross-sectional view of the inner tool misaligned with the outer tool at the top forming station of FIG. 3. FIG. [Figure 4B] 10A-10C illustrate the forces acting on the inner tool and its drive mechanism as a result of misalignment. [Figure 5] 10 is a flow chart illustrating an example of a manufacturing procedure for operating a top forming station. [Figure 6] 10 is a flow chart illustrating an example of a monitoring procedure associated with a top forming station. [Figure 7] 10 is a flow chart illustrating an example of a monitoring procedure associated with a top forming station. [Figure 8] FIG. 8 is an explanatory diagram showing an example of threshold values ​​used in the monitoring procedure of FIG. 7. [Figure 9A] 10 is a graph of measurement data obtained during operation of the top forming station. [Figure 9B] 10 is a graph of measurement data obtained during operation of the top forming station. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The embodiments will now be described in more detail with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject matter of this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

[0024] Where possible, any advantage, feature, function, device, and / or operational aspect of any of the embodiments described and / or contemplated herein may be included in any of the other embodiments described and / or contemplated herein, and / or vice versa. Additionally, where possible, terms used in the singular herein are intended to include the plural and / or vice versa, unless expressly stated otherwise. Thus, the terms "a" and / or "an" mean "one or more" or "at least one," but the expressions "at least one" or "one or more" are also used herein. The terms "multiple," "plural," and "plurality" are intended to mean the provision of two or more elements. The term "and / or" includes any and all combinations of one or more of the associated listed elements. Terms such as "first," "second," etc. may be used herein to describe various elements, but these elements should not be limited by these terms. These terms are used merely to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure.

[0025] Well-known functions or structures may not be described in detail for the sake of brevity and / or clarity. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0026] Like numbers refer to like elements throughout.

[0027] FIG. 1 shows a schematic diagram of an example of a production line for sealed packages containing liquid food products. The production line includes a series of stations 1 through 4. Sleeve-forming station 1 is configured to reshape a sheet material into a package body ("sleeve"). The package body may be cylindrical. The sheet material may be made of a paper-based laminate, as described in the Background of the Invention section. Top-forming station 2 is configured to provide a top at one open end of the sleeve, thereby completely or partially closing the open end of the sleeve. For example, the top may define an access opening. The access opening may or may not be covered by a film (foil) or cap when the package leaves top-forming station 2. In the example described below, top-forming station 2 is configured to provide the top by injection molding. After top-forming station 2, the package has an open end opposite the end where the top was provided. The production line may also include capping station 3 configured to attach a cap to the access opening. Filling station 4 is configured to fill the liquid food product into the package through an open end thereof and then seal the open end to form the final package containing the liquid food product. Filling station 4 may also be configured to sterilize the package prior to the filling operation.

[0028] Although not shown in FIG. 1, any one of stations 1-4 may be duplicated and operated in parallel to increase the throughput of the manufacturing line. Each station 1-4 may include one or more machines for performing the processing operations of the station. It is also possible for multiple stations to be implemented on a single machine.

[0029] The preferred designation "package" will be used throughout this specification. It will of course be understood that this designation also encompasses intermediate packages that may undergo various stages or states on their way to becoming a final package. The term final package is used herein to refer to a package that has been filled with product, sealed, and finally formed.

[0030] FIG. 2A is a side view of package 10 produced by top forming station 2 of FIG. 1. Package 10 is bottle-shaped and may have any cross-section, including, but not limited to, circular, square, rectangular, triangular, polygonal, etc. Package 10 is inverted. Package 10 includes sleeve 11, as described above, and top portion ("top") 12 coupled to sleeve end 11A. Opposite sleeve end 11B is open and provides a fill opening for filling package 10 with a liquid product. In the illustrated example, top portion 12 includes neck portion ("neck") 12A defining access opening or spout 12B. As described above, access opening 12B may be sealed by a membrane or foil (not shown). Alternatively, a cap (not shown) may be attached to neck portion 12A to close access opening 12B before the liquid product is filled into package 10. For example, one or more threads on the cap may engage threads 12C on neck 12A.

[0031] In some embodiments, the top portion 12 is made of a plastic material and formed by injection molding. The injection molding process bonds the top portion 12 to the sleeve end 11A along its circumference. FIG. 2B is a cross-sectional view of a portion of the interface between the top portion 12 and the sleeve 11 within the dashed circle 13 in FIG. 2A. As can be seen, the top portion 12 includes a thickened head portion 14 or "bead" formed to surround and attach to the circumferential sleeve end 11A. It is understood that the strength of the bond between the top portion 12 and the sleeve 11 depends on the shape and thickness of the bead 14 along the sleeve end 11A. If the bond is too weak at one or more points along the sleeve end 11A, the bond may break when a consumer attempts to open the package by removing the membrane and / or unscrewing the cap. If the formation of the bond is not well controlled, holes or cracks may form along the bond, potentially allowing liquid food to leak from the package. If a leak occurs at filling station 4, the production line may need to be stopped for cleaning, causing a costly production outage. Furthermore, food safety may be compromised if weak joints in the final package break, for example when the final package is distributed to retailers or consumers.

[0032] 3 is a side view of a top forming station or machine 2 according to a non-limiting example. Top forming station 2 includes a loading device 200, a processing device 210, and an unloading device 220. Loading device 200 is configured to receive incoming sleeves 11 and place the sleeves 11 in processing device 210, as indicated by arrow A1. Processing device 210 is configured to process the sleeves 11 into packages 10. Unloading device 220 is configured to remove packages 10 from processing device 210 for downstream processing, as indicated by arrow A4.

[0033] 3 also includes a controller 230 configured to control the operation of the top forming station 2. The controller 230 may or may not be a part of the station 2. The controller 230 may be implemented in hardware or a combination of software and hardware. In the illustrated example, the controller 230 includes a processor circuit 231, computer memory 232, and a signal interface 233. The processor circuit 231 may include, for example, one or more of a CPU (“Central Processing Unit”), a DSP (“Digital Signal Processor”), a microprocessor, a microcontroller, an ASIC (“Application-Specific Integrated Circuit”), a combination of discrete analog and / or digital components, or other programmable logic devices such as an FPGA (“Field Programmable Gate Array”). A control program including computer instructions (program instructions) may be stored in the memory 232 and executed by the processor circuit 231 to perform the methods and procedures described herein. The control program may be provided to the controller 230 on a computer-readable medium, which may be a tangible (non-transitory) product (e.g., magnetic medium, optical disk, read-only memory, flash memory, etc.) or a propagated signal. The signal interface 233 may be configured according to conventional practices to receive input signals and provide output signals. In the illustrated embodiment, the controller 230 is further connected to a feedback device 234 configured to generate audible and / or visible feedback to an operator of station 2. For example, the feedback device 234 may comprise one or more of a display, an indicator lamp, a speaker, a siren, etc.

[0034] The operation of the loading device 200 and the unloading device 220 is controlled by control signals from a control device 230, designated C2 and C4. The loading device 200 and the unloading device 220 may be configured in many different ways to perform their respective functions, and a detailed description thereof will be omitted. Examples are described in the aforementioned WO2007 / 106006.

[0035] The processing device 210 includes elongated arms 21 attached to or otherwise coupled with rotatable members 22, also known as wheels or mandrel wheels. Each arm 21 forms or includes an inner tool, also known as a mandrel. For ease of explanation, no distinction will be made between arms and inner tools hereinafter. The elongated arms 21 project radially from the wheels 22 and are equidistantly spaced around the wheels 22. The illustrated example includes four arms 21, each positioned at a right angle to the adjacent arm. A drive unit 23 is connected to the wheels 22 and operable to rotate the wheels 22, as indicated by arrow A2. The drive unit 23 may be an electric motor capable of precise angular positioning, such as a servo motor or stepper motor. The drive unit 23 is actuated by a control signal C1 from the controller 230. Specifically, the drive unit 23 is operable to intermittently rotate or index the wheels 22 and arms 21 to four different angular positions. The drive unit 23 stops at each angular position. The positions are indicated by Roman numerals in dashed circles in Figure 3. Position I is the loading position, where the arm 21 is aligned with the loading device 200. Position II is the processing position, where the arm 21 is aligned with the top forming device 24. Position III is the unloading position, where the arm 21 is aligned with the unloading device 220. Position IV is an intermediate rest position.

[0036] Providing four arms 21 allows for high throughput at station 2 and allows three operations to be performed simultaneously: loading sleeves 11 onto arms 21 with loading device 200, processing sleeves 11 on arms 21 with top forming device 24, and unloading packages 10 from arms 21 with unloading device 220. However, wheel 22 may be provided with any number (n) of arms 21, where n≧1.

[0037] Arms 21 extend from wheels 22 in a common plane, which defines the plane of rotation of arms 21. In some embodiments, the plane of rotation may be vertical or horizontal.

[0038] The top-forming device 24 includes an outer tool 25 that is movable relative to the arm 21 when in position II. In the illustrated example, the outer tool 25 is linearly movable between a rest position and an operating position, as indicated by double-headed arrow A3. In the rest position, the outer tool 25 is spaced apart from the arm 21. In the operating position, the outer tool 25 is positioned to surround the distal end of the arm 21, thereby surrounding the end 11A (FIG. 2A) of the sleeve 11 disposed on the arm 21. An actuator 26 is connected to the outer tool 25 and operable to impart movement thereto. It should be emphasized that FIG. 3 is merely exemplary. The outer tool 25 may be movable in additional directions relative to the operating position. Furthermore, the outer tool 25 may be composed of separately movable parts that converge in the operating position. In the operating position, the outer tool 25 is operable to provide the top 12 on the sleeve end 11A. The top-forming operation by the device 24 is controlled by one or more control signals from a controller 230, represented by C3.

[0039] As mentioned above, the top portion 12 may be formed on the sleeve 11 by injection molding. In such an embodiment, the outer tool 25 is an injection molding apparatus. In the operative position of the outer tool 25, the sleeve end 11A (FIG. 2A) is surrounded by the outer tool 25 to engage the sleeve end 11A between the end of the arm 21 and the outer tool 25 during injection molding.

[0040] More specifically, when the outer tool 25 is positioned to surround the end of the inner tool 21 and the end of the package body, a small gap is formed that extends between the outer tool 25 and the end of the inner tool 21 and the end of the package body. Operation of the outer tool 25 to provide the top portion 12 on the end of the package body (sleeve) 11 typically involves injecting a plastic material, or other suitable material, into the gap. The injection-molded portion formed by the gap then becomes the package top portion 12. Techniques for injection molding a plastic top portion 12 onto a sleeve 11 are conventional and will not be described in detail herein.

[0041] FIG. 5 is a flowchart of a procedure 100 for operating the top forming station 2 to produce a package 10 starting from a sleeve 11. The production procedure 100 may be implemented by operating the controller 230 to provide appropriate control signals C1-C4 via its signal interface 233. As described above, each arm is or includes an inner tool 21 that cooperates with an outer tool 25 during the top forming operation. In step 101, the wheel 22 is operated to place the inner tool 21 in a loading position. In FIG. 3, step 101 includes operating the drive unit 23 to rotate the wheel 22 to a predetermined angular position corresponding to position I. In step 102, the sleeve 11 is placed on the inner tool 21 while the inner tool 21 is in the loading position. In FIG. 3, step 102 includes operating the loading device 200 to press or slide the sleeve 11 onto the inner tool 21 in position I. In step 103, the wheel 22 is operated to move the inner tool 21 carrying the sleeve 11 from the loading position to a processing position at a predetermined angular position of the wheel 22. In FIG. 3 , step 103 includes operating the drive unit 23 to rotate the wheel 22 and swing the inner tool 21 from position I to position II. In step 104, the outer tool 25 is positioned to surround the end of the inner tool 21, thereby surrounding the sleeve end 11A. In FIG. 3 , step 104 includes operating the actuator 26 to move the outer tool 25 toward the inner tool 21 and to the operating position. In step 105, the outer tool 25 is operated to provide the top portion 12 on the sleeve end 11A, thereby manufacturing the package 10. As described above, step 105 may include operating the outer tool 25 to perform injection molding to form the top portion 12 on the sleeve end 11A. In step 106, the wheel 22 is operated to move the inner tool 21 carrying the package 10 from the processing position to an unloading position at a predetermined angular position of the wheel 22.In Figure 3, step 106 involves operating the drive unit 23 to rotate the wheels 22 and swing the inner tool 21 from position II to position III. In step 107, the package 10 is removed from the inner tool 21 while the inner tool 21 is in the unloading position. In Figure 3, step 107 involves operating the unloading device 220 to pull or slide the package 10 off the inner tool 21 at position III. In the context of Figure 3, step 107 is followed by a step (not shown) of operating the wheels 22 to move the inner tool 21 from position III to position IV. It should be noted that position IV may be omitted depending on the number of arms 21 and their mutual arrangement.

[0042] Manufacturing procedure 100 is then repeated to produce a stream of packages 10. It is understood that procedure 100 may be performed for each arm 21 of processing apparatus 210, or preferably may be performed such that steps 102, 104-105, and 107 are performed simultaneously for different arms 21, i.e., a sleeve 11 is loaded onto one arm 21 at position I, a top 12 is formed onto the sleeve 11 on another arm 21 at position II, and a package 10 is unloaded from yet another arm 21 at position III.

[0043] Applicant has realized that the relative positioning of the inner tool 21 and the outer tool 25 during the top-forming operation is critical to the quality of the package 10. Poor alignment of the inner tool 21 and the outer tool 25 during the top-forming operation can result in the top 12 being formed with an undesirable appearance / thickness and / or a poor connection with the sleeve 11. FIG. 4A illustrates an example of such misalignment, showing a cross-sectional view of the inner tool 21 and the outer tool 25 during the top-forming operation. The inner tool 21, carrying the sleeve 11, is positioned in position II, and the outer tool 25 is positioned in the operating position. This positions the end of the inner tool 21 and the sleeve end 11A within the top-forming cavity 25B of the outer tool 25. In the illustrated example, the inner tool 21 is slightly tilted relative to the outer tool 25 in the plane of rotation, as indicated by the angle α between the axis of symmetry 25A of the outer tool 25 and the longitudinal axis 21A of the inner tool 21. Applicant has realized that if misalignment can be detected and quantified, it is possible to correct the misalignment, thereby improving the performance of station 2. In the example of FIG. 4A, the correction may comprise modifying the predetermined angular position of wheel 22 at position II to reduce angle α. After much experimentation, Applicant has discovered that the lateral force acting on inner tool 21 can be analyzed to detect misalignment. In the example of FIG. 4A, tilting of inner tool 21 relative to outer tool 25 increases the lateral force LF on inner tool 21 as it presses against the wall of cavity 25B.

[0044] Based on these insights and significant experimentation, applicant has devised a monitoring procedure for detecting and correcting misalignment between the inner tool 21 and the outer tool 25 in the top forming station 2. The monitoring procedure comprises determining, based on the measurement signals, at least one parameter value indicative of a lateral force acting on the inner tool 21 at position II while the outer tool 25 is positioned to surround the end of the inner tool 25. The monitoring procedure further comprises selectively adjusting the relative position between the inner tool 21 and the outer tool 25 based on the at least one parameter value. The monitoring procedure is further illustrated and described below with reference to Figures 6 to 9.

[0045] The measurement signal may be provided in many different ways. As shown in FIG. 3, one or more sensors 26 may be arranged at station 2 to generate a measurement signal S1 indicative of the lateral force LF. Each sensor 26 may be, for example, a force sensor, a strain sensor, or a torque sensor. Each sensor 26 may be associated with the drive unit 23 (as shown), the inner tool 21, the wheel 22, or the outer tool 25. In some embodiments, the measurement signal S1 may be generated by the drive unit 23 and represent the torque required to hold the wheel 22 in a fixed angular position, i.e., position II. FIG. 4B illustrates a situation in which the drive unit 23 generates a torque T about the axis of rotation of the wheel 22 to withstand the lateral force LF acting on the end of the inner tool 23. The torque T may be provided by the instantaneous drive force or drive current of the drive unit 23 or obtained from a dedicated torque sensor in the drive unit 23. Electric motors are commercially available that are configured to provide a measurement signal indicative of the current torque. Examples of such motors include Rockwell Automation servo motors such as model MPL-B420P-M and Wittenstein servo motors such as model TPM050x-031P-6.

[0046] At least one parameter value may indicate both the magnitude and direction of the lateral force. For example, opposite directions may be assigned a positive or negative sign. In the example of FIG. 4B, the sign of the torque T indicates whether the lateral force (LF) is clockwise or counterclockwise.

[0047] An example of the monitoring procedure 200 is shown in the flowchart of FIG. 6. The monitoring procedure 200 may be performed by the control device 230 based on the measurement signal S1 received via the signal interface 233 and any further input signals that may be required. In step 201, the control device 230 waits until the outer tool 25 is in its operating position relative to the inner tool 21 before proceeding to step 202. For example, in step 201, the control device 23 may wait until an output signal (not shown) from the drive unit 23 confirms that the inner tool is in position II and an output signal (not shown) from the actuator 26 confirms that the outer tool 25 is in the operating position. Alternatively, the control device 230 may wait a predetermined time in step 201. In step 202, the measurement signal S1 is processed to determine at least one parameter value. In some embodiments, in step 202, multiple parameter values ​​indicative of lateral forces are determined. In step 203, the at least one parameter value is evaluated with respect to an acceptance criterion (e.g., a threshold value as described below). If at least one parameter value indicates that there is a sufficiently small (or no) misalignment between the inner tool 21 and the outer tool 25, the acceptance criterion is met. If the acceptance criterion is met, the procedure 200 returns to step 201. If not, the controller 230 executes step 204, in which the relative position between the inner tool 21 and the outer tool 25 is adjusted based on at least one parameter value. Step 204 may comprise adjusting the position of the inner tool 21, the outer tool 25, or both. Specifically, the adjustment is performed to reduce the misalignment and, therefore, reduce the lateral force acting on the inner tool 21. The adjustment may be performed by a mathematical function or a look-up table relating the adjustment to the parameter value. The adjustment may take into account not only the magnitude of the lateral force, but also its direction.

[0048] In the example of FIGS. 4A-4B, at least one parameter value indicates a lateral force LF in the rotation plane of the arm 21. With such a parameter value, the relative position between the inner tool 21 and the outer tool 25 is adjusted only in this rotation plane. The inner tool 21 may be adjusted by changing the rotation angle of the wheel 22 to decrease the angle α, and the outer tool 25 may be adjusted by shifting its position laterally, i.e., laterally relative to the line of symmetry 25A, and / or by tilting the outer tool 25. In some embodiments, the relative position between the inner tool 21 and the outer tool 25 is adjusted only by changing the rotation angle of the wheel 22. Such an adjustment is simple to perform and avoids the complexity of moving the outer tool 25. In the example of FIGS. 4A-4B, the wheel 22 may be rotated counterclockwise to decrease the angle α.

[0049] If the lateral forces are measured in a geometric plane other than the plane of rotation, it is contemplated that the adjustments in step 204 may be made in this geometric plane, provided that station 2 is equipped with appropriate structure for such adjustments. However, it is presently believed that adjustments in the plane of rotation are most appropriate.

[0050] In some embodiments, monitoring procedure 200 is performed concurrently with manufacturing procedure 100, specifically during the top forming operation (steps 104-105 in FIG. 3). Monitoring procedure 200 can thereby detect and correct alignment errors that occur during production, thereby minimizing the risk of producing a large number of defective packages. In some embodiments, monitoring procedure 200 is performed as a preliminary inspection before manufacturing procedure 100 begins. The preliminary inspection aims to correct any existing misalignment between the inner tool and the outer tool. During the preliminary inspection, station 2 may be operated to produce a limited number of packages 10. Alternatively, the preliminary inspection may be performed with the sleeve attached to the inner tool, without operating the outer tool. As another alternative, the preliminary inspection may be performed without attaching the sleeve to the inner tool, thereby eliminating the need to operate the outer tool to form the top.

[0051] FIG. 7 is a flowchart of another example of a monitoring procedure 200. The example in FIG. 7 assumes that there are multiple inner tools 21 on the wheel 22, as shown in FIG. 3 . Procedure 200 includes two evaluations for assessing the need for correction: a slow evaluation and a fast evaluation. The slow evaluation is performed after one revolution of the wheel 22 and is based on a set of parameter values ​​acquired for all inner tools 21 during that revolution. If the set of parameter values ​​indicates a certain misalignment between the inner and outer tools, the position of the wheel and / or outer tools is adjusted to reduce the misalignment. This adjustment is performed for all inner tools collectively, for example, to reduce the average misalignment of all inner tools or to reduce the maximum misalignment among the inner tools. The slow evaluation thus serves to evaluate the processing apparatus 210 as a whole and, if necessary, find acceptable adjustments for all inner tools. Performing the evaluation and adjustments individually for each inner tool risks runaway correction, i.e., adjustments to one inner tool necessitate adjustments to the next inner tool, because all inner tools are fixedly positioned on a common wheel. This runaway correction can be avoided by slow evaluation.

[0052] Meanwhile, the fast evaluation is performed individually for each inner tool 21, but is adjusted to detect larger misalignments than the slow evaluation to reduce the risk of runaway correction. If parameter values ​​indicate a large enough misalignment, adjustments are made. The fast evaluation detects misalignments that could result in excessive performance degradation or mechanical damage to the inner tool or other tools. The fast evaluation is based on the insight that if there is a large misalignment between one inner tool and an outer tool, this misalignment is likely to be present for all inner tools on the wheel 22.

[0053] The procedure of FIG. 7 includes steps 201 and 202, which are identical to the corresponding steps of FIG. 6. Thus, procedure 200 waits until the outer tool is positioned to surround the end of the inner tool (step 201) and determines at least one parameter value PV (step 202). Next, procedure 200 proceeds to perform a fast evaluation via step 203A, in which a representative magnitude value PVR2 for PV is determined and compared to a threshold value TH2. If PVR2 exceeds TH2, procedure 200 proceeds to step 204A, in which an adjustment is made to counteract the deviation represented by PV. If multiple parameter values ​​were determined in step 202, PVR2 may be given as the mean, median, mode, maximum, minimum, etc., of the multiple parameter values. If a single parameter value was determined in step 202, PRV2 may be set to the magnitude of this parameter value. In some embodiments, step 204A includes calculating an adjustment to be applied by the controller when subsequently aligning the inner and outer tools (see steps 103-104 of FIG. 3). For example, the adjustment value may change the predefined angular position of wheel 22 to place the next inner tool at position II. After step 204A, procedure 200 proceeds to monitor the next inner tool on the wheel (step 205). If PRV2 does not exceed TH2 in step 203A, the procedure proceeds to step 203B to check whether the parameter values ​​have been determined for all inner tools, i.e., a complete rotation of the wheel. If so, procedure 200 proceeds to monitor the next inner tool (step 205).

[0054] Once all inner tools have been monitored, step 203B proceeds to step 203C, which performs a consistency check of the set of parameter values ​​(designated [PV]) determined in step 202 for the inner tools during a complete wheel revolution. The consistency check in step 203C looks for inconsistent directions within [PV]. As discussed above, parameter values ​​can represent both the magnitude and direction of lateral forces. For example, step 203C may identify an inconsistency if [PV] contains parameter values ​​with different signs, meaning that corresponding lateral forces are in opposite directions. To identify an inconsistency, step 203C may also require that the magnitude of the parameter value exceed a threshold, i.e., that the inconsistent lateral forces have an associated magnitude. If step 230C identifies an inconsistency, procedure 200 proceeds to step 206, which generates an alert to the controller, for example, via a feedback device (see 234 in FIG. 3). Alternatively or additionally, step 206 may cause the controller to stop operation of the top forming station. The motivation for the consistency check in step 203C is that the direction of the lateral force should be the same for all inner tools: if the direction is different, a mechanical error may have occurred, for example, one or more inner tools may have been bent or deformed.

[0055] If no discrepancy is found in step 203C, the procedure proceeds to step 203D, where a slow velocity evaluation is performed, and a representative value of [PV], PVR1, is determined and compared to a threshold value, TH1. PRV1 may be given as the mean, median, mode, maximum, minimum, etc., of the parameter value of [PV]. The calculation of PRV1 is based on the magnitude and, optionally, its sign of the parameter value. As understood from the above discussion, TH1 is less than TH2. If PVR1 exceeds TH1, the procedure 200 proceeds to step 203E, where an appropriate adjustment is estimated based on [PV], and the relative position is adjusted accordingly, at step 204B. For example, the appropriate adjustment may be estimated based on PRV1 or another representative value of [PV] using a lookup table or a mathematical function. In some embodiments, step 203E results in an adjustment, e.g., an angle change, to be applied by the controller when subsequently aligning the inner and outer tools (see steps 103-104 in FIG. 3). After step 204B, the procedure 200 proceeds to monitor the next inside tool on the wheel (step 205).

[0056] FIG. 8 illustrates TH1 and TH2 on a lateral force scale, LF. The scale extends from zero (0) to a maximum value, MAX. As shown, TH1 and TH2 separate the scale into three force ranges. The range between TH1 and TH2 results in slow adjustment, per steps 203E and 204B. The range between TH2 and MAX results in fast adjustment, per step 204A. In the range between 0 and TH1, no adjustment is performed. Note that FIG. 8 assumes that the lateral force is given by a positive number, i.e., a magnitude value. Currently, it is believed that sufficient performance is achieved, at least for the Rockwell Automation and Wittenstein motors exemplified above, by setting TH1 between 10% and 40% of MAX and TH2 between 60% and 90% of MAX. In some embodiments, TH1 is set between 20% and 30% of MAX and TH2 is set between 70% and 80% of MAX.

[0057] In the example of FIG. 7, the adjustment to be made is determined based on the lateral force acting on the current inner tool engaged with the outer tool, and then the adjustment is applied to the next inner tool that is aligned with the outer tool. It is conceivable to apply the adjustment to the current inner tool to achieve an immediate correction of the current inner tool. However, if the end of the current inner tool is locked within the outer tool, such an immediate correction is not possible. Furthermore, an immediate correction may cause instability in the position control of the inner and outer tools.

[0058] Note that the monitoring procedure of Figure 7 may be modified by omitting any of the consistency checks, fast evaluations, and slow evaluations, depending on the perceived risk and desired monitoring performance for a particular top forming station.

[0059] 9A-9B are included to illustrate the utility of the slow-speed correction of the processing unit 201 of FIG. 3. In FIG. 9A, signal 80 specifies the angular position of the wheel 22, given as an indexed angle value between 0° and 90°. As the angle value increases from 0° to 90°, the wheel 22 rotates a quarter-turn, at which point the angle value is reset to 0°. Time P1 indicates the time during which the wheel 22 is stationary, approximately 1.6 seconds in this case. During P1, a top-forming operation is performed. Time P2 indicates the duration of one rotation of the wheel 22, and therefore corresponds to four top-forming operations, one for each inner tool 21 on the wheel 22. A full rotation of the wheel 22 is also referred to as a "full production cycle," or FPC. Signal 81 represents the execution state of the software code executed by the controller 230 at each time step. The execution states correspond to subsets of the software code. The numbering of the execution states is arbitrary and is provided merely to indicate when the corresponding execution states occur in time. Reference symbol S indicates data sampling, which corresponds to step 202 in FIGS. 6-7, thereby obtaining parameter values. In the illustrated example, five parameter values ​​are obtained for each time period P1. Sampling multiple parameter values ​​for each time period P1 reduces the effect of erroneous data samples. Reference symbol E1 designates the execution step corresponding to steps 203A and 203B in FIG. 7, and optionally step 204A if fast correction is initiated. While E1 is shown only once in FIG. 9A, it should be understood that each data sampling S is followed by E1. Reference symbol E2 designates a set of execution states corresponding to steps 203D, 203E, and 204B. E2 thus results in slow correction. Reference symbol E2' designates the set of execution states corresponding to step 203D, i.e., no slow correction.

[0060] Turning to FIG. 9B, signal 82, in conjunction with the data in FIG. 9A, represents the torque of the drive unit 23, here the servo motor. In this example, the lateral force is provided by the torque. Therefore, the parameter value is the torque value. In FIG. 9B, data sampling occurs within a time period ΔS during each top-forming operation. During ΔS, the torque value is relatively stable because the wheel 22 is stationary. The spikes at the beginning and end of period P1 represent the torque of the drive unit 23 as the wheel 22 accelerates and decelerates. For clarity, the entire successive production cycles are listed at the top of FIG. 9B, from FPC1 to FPC5. The dashed horizontal lines indicate the positions of TH1 and TH2 on the torque scale. As shown in FIG. 9B, the torque value during the top-forming operation is less than TH2, so no high-speed correction is initiated. In FPC1, the torque value is greater than TH1, so a low-speed correction (E2) is performed for the next FPC2. In FPC2, the low-speed correction results in a decrease in the torque value. However, the torque value is still greater than TH1, so another low speed correction (E2) is performed for the next FPC3. This is repeated for the next FPC4, where the torque value is less than TH1, so the controller does not perform a low speed correction (E2') for the next FPC5. Therefore, for FPC5, the torque value is almost the same as for FPC4.

[0061] The drawings, and particularly FIG. 7 , can be seen to illustrate several embodiments of a monitoring procedure associated with a top section forming machine or station operated according to the manufacturing procedure 100 of FIG. 5 . The top section forming machine includes a plurality of inner tools arranged to project radially from a rotatable member, and the manufacturing procedure is repeated for each inner tool of the plurality of inner tools. In one embodiment, the monitoring procedure includes determining at least one parameter value for each inner tool of the plurality of tools (step 202) while an outer tool is arranged to surround an end of each inner tool, performing an evaluation of a resultant data set [PV] of the estimated parameter values ​​for the plurality of inner tools (steps 203C, 203D, 203E), and selectively altering the rotation angle of the rotatable member based on the evaluation (step 204B). In one embodiment, the rotation angle of the rotatable member is altered for future iterations of the manufacturing procedure. In other words, the rotation angle is altered when the next inner tool is aligned with the outer tool. In one embodiment, [PV] associates each parameter value with a direction of the lateral force in the plane of rotation, and the evaluation comprises evaluating [PV] for detecting a mismatched direction (step 203C) and generating a warning signal upon detecting a mismatched direction (step 206). In one embodiment, the evaluation comprises evaluating [PV] against a threshold value TH1 (step 203D), and upon detecting that a representative value PVR1 of [PV] exceeds TH1, determining an angle adjustment value for the rotatable member based on [PV] (step 203E), wherein the rotation angle of the rotatable member is changed according to the angle adjustment value. In one embodiment, the angle adjustment value is determined based on PVR1 (step 203E). In one embodiment, PVR1 is a mean, median, mode, maximum, or minimum value. In one embodiment, the monitoring procedure further includes evaluating, during each manufacturing procedure, at least one parameter value of each inner tool in relation to a further threshold value TH2 that exceeds TH1 (step 203A), and changing the rotation angle of the rotatable member upon detecting that a representative value PVR2 of the at least one parameter value exceeds TH2 (step 204A).In one embodiment, the rotation angle is changed based on PVR2 exceeding TH2.

[0062] The present disclosure is not limited to the use of injection molding to provide the top portion on the sleeve. For example, the outer tool may be configured for other types of molding, such as blow molding, compression molding, thermoforming, etc. In a variant, the outer tool is configured to attach a pre-fabricated top portion or portion thereof onto the sleeve, for example by gluing, melting, mechanical attachment, etc. In a further variant, the outer tool is configured to mold a portion of the sleeve into the top portion or portion thereof. Examples of such molding are described in WO2010 / 085182 and DE102005048821.

[0063] Additionally, the sleeve may be made of or include materials other than a paper-based laminate, such as cardboard or a plastic material. The top portion may be made of any suitable material or combination of materials. Furthermore, the techniques disclosed herein are applicable to the production of non-bottle-shaped packages. The monitoring techniques described herein are equally applicable to machines configured to produce packages for holding liquid food products by providing a bottom portion at the end of the sleeve. Accordingly, references herein to a "top portion" may be replaced with a "bottom portion" or the more general term "end portion."

Claims

1. A computer implementation method for operating a machine (2) that manufactures a package (10) for holding liquid food, The machine (2) comprises an inner tool (21) and an outer tool (25), wherein the inner tool (21) protrudes radially from a rotatable member (22) that can be operated to move the inner tool (21) from a loading position (I) to a machining position (II), and the outer tool (25) can be operated to surround the end of the inner tool (21). The above method comprises a manufacturing procedure (100), and the manufacturing procedure (100) is The rotatable member (22) is operated (101) to position the inner tool (21) at the loading position (I), Placing the package body (11) on the inner tool (21) at the loading position (I) (102), The rotatable member (22) is operated (103) to move the inner tool (21) together with the package body (11) from the loading position (I) to the processing position (II), The outer tool (25) is positioned (104) to surround the end of the inner tool (21), thereby surrounding the end of the package body (11). The external tool (25) is operated (105) to provide a top portion (12) to the end of the package body (11), thereby manufacturing the package (10). Equipped with, The method further comprises a monitoring procedure (200), the monitoring procedure (200) is Based on the measurement signal (S1), determine at least one parameter value (PV) that indicates the lateral force (LF) acting on the inner tool (21) at the machining position (II) while the outer tool (25) is positioned to surround the end of the inner tool (21) (202), Based on the aforementioned at least one parameter value (PV), selectively adjust the relative position between the inner tool (21) and the outer tool (25) (204), Equipped with, Computer implementation method.

2. The measurement signal (S1) is generated while the package body (11) is positioned on the inner tool (21) at the processing position (II) and the outer tool (25) is being operated to provide the top portion (12) to the end of the package body (11). The method according to claim 1.

3. The measurement signal (S1) indicates a lateral force (LF) and is obtained from an electric motor (23) connected to and operable for rotating the rotatable member (22), or from a sensor (S1) associated with the machine (2). The method according to claim 1.

4. The at least one parameter value (PV) represents the lateral force (LF) in the rotation plane of the inner tool (21), and the rotation angle of the rotatable member (22) is changed to adjust the relative position between the inner tool (21) and the outer tool (22). The method according to claim 1.

5. The machine (2) comprises a plurality of internal tools (21) arranged to protrude radially from the rotatable member (22), The above manufacturing procedure (100) is repeated for each of the multiple inner tools (21), The aforementioned monitoring procedure (200) is: While the outer tools (25) are positioned to surround the ends of each inner tool (21), determine at least one parameter value (PV) for each of the inner tools (21) among the multiple tools (202), and Evaluating a dataset of estimated parameter values ​​([PV]) for multiple internal tools (203C, 203D, 203E), and selectively changing the rotation angle of the rotatable member (22) based on the evaluation (203C, 203D, 203E) (204B). Equipped with, The method according to claim 4.

6. The rotation angle of the rotatable member (22) is changed with respect to subsequent repetitions of the manufacturing procedure (100). The method according to claim 5.

7. The aforementioned result dataset ([PV]) associates each of the parameter values ​​with the direction of the lateral force (LF) in the plane of rotation. The evaluation described above (203C, 203D, 203E) comprises evaluating the result dataset ([PV]) for the detection of conflicting directions (203C), and generating a warning signal when conflicting directions are detected (206). The method according to claim 5.

8. The evaluation described above (203C, 203D, 203E) is The obtained dataset ([PV]) is evaluated in relation to the threshold (TH1) (203D), When it is detected that the representative value (PVR1) of the obtained dataset ([PV]) exceeds a threshold (TH1), the angle adjustment value of the rotatable member (22) is determined based on the obtained dataset ([PV]) (203E), Includes, The rotation angle of the rotatable member (22) is changed according to the angle adjustment value. The method according to claim 5.

9. The angle adjustment value is determined based on the representative value (PVR1) (203E). The method according to claim 8.

10. The aforementioned representative value (PVR1) is the mean, median, mode value, maximum value, or minimum value. The method according to claim 8.

11. The monitoring procedure (200) includes evaluating, during each manufacturing procedure (100), at least one parameter value (PV) for each internal tool (21) in relation to a further threshold (TH2) that exceeds a threshold (TH1) (203A). When it is detected that the representative value (PVR2) of at least one parameter value (PV) exceeds a further threshold (TH2), the rotation angle of the rotatable member (22) is changed (204A). Furthermore, The method according to claim 8.

12. The rotation angle of the rotatable member (22) is changed based on a representative value (PVR2) that exceeds a further threshold (TH2). The method according to claim 11.

13. The package (10) is in the shape of a bottle. The method according to claim 1.

14. A computer-readable medium containing program instructions, which, when executed by a processor circuit (231), is configured to cause the processor circuit (231) to perform the method according to claim 1.

15. A control device configured to perform the method described in claim 1, wherein the control device comprises a signal interface (233) configured to receive a measurement signal (S1) and to provide control signals (C1 to C4) for operating a machine (2).

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