Machine arrangement for joining lid and container

Abstract

A control device performs a method (200) for configuring a capping machine operable to engage a threaded cap with a threaded neck of a container. In the method, APs are sequentially selected (201) from a predefined set of angular positions (APs) of the cap, where each AP corresponds to a direction of the cap relative to the neck. For each AP, a cap installation test (100) is performed in which the capping machine is operated to engage a plurality of caps disposed in the selected AP with the necks on the respective containers. The capping operation (202) is evaluated to achieve consistent capping performance. The method is performed until a consistent capping performance is detected for a sequence of adjacent APs corresponding to a sequence of spatially adjacent lid directions. The capper (204) is then configured by setting its operating APs relative to the sequence of adjacent APs.

Description

Technical Field

[0001] The present invention relates to the production of packages containing food products and in particular to the art of configuring a capping machine operable to screw a threaded cap onto a threaded neck of a container. Background Art

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

[0003] One common type of package is manufactured by forming a sleeve of the above-mentioned paper-based laminate material, sealing one end of the sleeve to form a neck defining a pouring spout, attaching a lid over the pouring spout, filling the liquid food product through the opposite open end of the sleeve and sealing the open end to form a final package ready for dispensing. This is just one example. There are many other types of paper-based laminate packages in which a lid is attached over the pouring spout.

[0004] The attachment of the cap is performed in a capping machine which is configured to rotate the cap so that the threads on the cap are securely engaged with corresponding threads on the neck. An example of such a capping machine is described in WO2016 / 177750.

[0005] Industrial production and packaging of liquid foods is automated and involves advanced mechanical process control to enable high-volume production. Safe and reliable operation is extremely important, as operational failures and the resulting production stoppages can have a profound impact on production costs and product quality. For example, it is critical to avoid operational failures that could damage machinery or cause large batches of produced packaging to be scrapped.

[0006] The capping operation is susceptible to operator errors, as incorrectly attaching the cap to the neck may result in damaged threads, inadequate sealing, leakage, etc. Such a package needs to be discarded. Incorrect attachment may also lead to subsequent problems in downstream production, such as the need to clean up leaking food at the filling station.

[0007] The above-mentioned WO2016 / 177750 proposes to determine the starting angle of the cap used when engaging the cap with the neck, and configure the capping machine to use this starting angle in production. This determination is done by performing multiple capping operations at different starting angles while looking for the starting angle that results in poor capping performance. The machine is then configured to use a starting angle that is offset by 60° relative to the starting angle that results in poor capping performance. The basic principle is that the capping performance is poor when the end of the thread on the cap meets the end of the thread on the neck. By offsetting the starting angle by 60°, the end of the thread on the cap should be arranged in the middle of the end of the thread on the neck, assuming that the cap and the neck each have three threads, with the starting points of the threads being 120° apart.

[0008] However, it has been found that this blind deviation from poor capping performance may not provide the proper starting angle to incorrectly attach the cap to the neck in production. Therefore, an alternative technique for configuring a capping machine is needed. Summary of the invention

[0009] It is an object to at least partially overcome one or more limitations of the prior art described above.

[0010] One such object is to provide a technique for configuring a capping machine to screw a threaded cap onto a threaded neck of a container.

[0011] Another object is to provide a technique for finding the proper starting angle of the cap relative to the neck to mitigate the risk of the cap being incorrectly attached to the neck.

[0012] One or more of these objects, as well as further objects that may emerge from the following description, are achieved at least in part by a computer-implemented method of configuring a capping machine, a computer-readable medium and a control device as described herein, embodiments of which are defined by the dependent claims.

[0013] A first aspect relates to a computer-implemented method for configuring a capping machine, wherein when the capping machine is configured, the capping machine is operable to arrange a cap at a given angular position relative to a neck on a container and to rotate the cap relative to the neck so that a threaded portion of the cap is fully engaged with a corresponding threaded portion of the neck. The method comprises: sequentially selecting angular positions from a predefined set of angular positions of the cap until a termination condition is satisfied, wherein the angular positions in the predefined set correspond to different orientations of the threaded portion of the cap relative to the threaded portion of the neck; for each selected angular position, operating the capping machine to perform a plurality of capping operations, wherein each of a plurality of caps is arranged at a selected angular position and rotated to fully engage with a corresponding neck on a corresponding container; and evaluating the plurality of capping operations to achieve consistent capping performance at the selected angular positions. The termination condition requires detection of consistent capping performance of a sequence of adjacent angular positions corresponding to a sequence of spatially adjacent orientations of the threaded portion of the cap relative to the threaded portion of the neck. The method further comprises: configuring the capping machine by setting a given angular position relative to the sequence of adjacent angular positions.

[0014] The method of the first aspect performs an active search for consistent capping performance in a set of predefined angular positions. When a consistent capping performance of a continuous range of lid directions represented by a sequence of adjacent angular positions is detected, the active search terminates. In other words, the sequence of adjacent angular positions defines a spatially continuous step of the lid direction relative to the neck of the container. Compared with the prior art, the method of the first aspect significantly reduces the risk of the capping machine outputting containers with incorrectly attached lids during production. The active search for a sequence of adjacent angular positions with consistent capping performance itself leads to a high probability of verifying that there is a continuous range of lid directions that can be used to configure the capping machine. In turn, verification makes it possible to configure the capping machine so as to achieve stable and consistent capping performance in production. The method of the first aspect limits the loss of containers and lids because the search automatically terminates when the termination condition is met. Therefore, there is no need to search all predefined angular positions.

[0015] As used herein, "liquid food" refers to any non-solid, semi-liquid or pourable food at room temperature, including beverages such as water, juice, wine, liquor, soda, as well as dairy products, sauces, oils, creams, custards, soups, dressings, etc., and solid foods in liquids, such as beans, fruits, tomatoes, stews, etc.

[0016] As used herein, "package" refers to any package or container suitable for holding a liquid food, including but not limited to containers formed from paperboard or paper-based laminate materials, and containers made of or comprising plastic materials.

[0017] A second aspect relates to a computer-readable medium comprising program instructions, which, when a processor circuit executes the program instructions, are configured to cause the processor circuit to perform the method of the first aspect or any embodiment thereof.

[0018] A third aspect relates to a control device configured to perform the method of the first aspect or any embodiment thereof, the control device comprising a signal interface for providing control signals for operating a capping machine and receiving input signals indicative of capping performance.

[0019] Other objects, features, embodiments, aspects and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A is a schematic diagram of a sequence of processing stations in an example production line for manufacturing packages containing food products, and Figure 1B yes Figure 1A Schematic diagram of the capping machine in the production line.

[0021] Figure 2A-2BPerspective views of the lid and container before and after the capping operation, respectively.

[0022] Figure 3A-3B is a schematic side elevation view (partially in cross-section) of a cap with the thread ends having two different angular orientations relative to the thread ends on the container.

[0023] Figure 4 is a bottom plan view of an example cap having three equally spaced threaded ends.

[0024] Figure 5 is a flow chart of an example lid installation test process.

[0025] Figure 6 is a graph of measurement data obtained during a lid installation test process.

[0026] Figure 7 is a flow chart of an example configuration method of a capping machine.

[0027] Figure 8 yes Figure 7 Diagram of example lid orientation angles used in the method.

[0028] Fig. 9 is a flow chart of an example configuration method of a capping machine.

[0029] Figures 10A-10B Shown in Figure 6 Background use Figure 8 When the cover direction angle is Fig. 9 An example of the operation of the configuration method.

[0030] Fig.11 Shown with Figure 6 The length threshold associated with the measurement data in .

[0031] Fig.12 is a flow chart of an example process for determining a length threshold.

[0032] Fig.13 is used for Fig. 9 Flowchart of an example validation process for a method.

[0033] Figures 14A-14B An example of the operation of the verification process is shown. DETAILED DESCRIPTION

[0034] Embodiments will now be described more fully with reference to the accompanying drawings, in which some but not all embodiments are shown. Indeed, the subject matter of the present 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 may satisfy applicable legal requirements.

[0035] Where possible, any advantages, features, functions, equipment and / or operational aspects of any embodiment described and / or envisioned herein may be included in any other embodiment described and / or envisioned herein, and / or vice versa. In addition, where possible, any term expressed in the singular herein is also meant to include plural forms and / or vice versa, unless otherwise expressly stated. Therefore, the term "one" and / or "one" should mean "at least one" or "one or more", even if the phrase "one or more" or "at least one" is also used herein. The terms "multiple", "plural" and "many" are intended to imply that two or more elements are provided. The term "and / or" includes any and all combinations of one or more related listed elements. Although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element without departing from the scope of the present disclosure.

[0036] For brevity and / or clarity, well-known functions or constructions may not be described in detail. 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 the present disclosure belongs.

[0037] Like reference numerals refer to like elements throughout.

[0038] Figure 1ASchematically illustrated is an example production line for producing a sealed package containing liquid food. The production line includes a sequence of stations 1-4. Sleeve forming station 1 is configured to reshape sheet material into a cylindrical packaging body ("sleeve"). The sheet material can be made of a paper-based laminate as discussed in the background section. Top forming station 2 is configured to receive the sleeve from station 1 and provide a top on an open end of the sleeve to form a container. The top includes a threaded neck that defines an entry opening. The neck is also referred to as a "finish" in the art. The entry opening may be covered or may not be covered by a film (foil). The neck is generally made of plastic material and may be incorporated into the top in different ways. In one embodiment, such as described in WO2007 / 106006, top forming station 2 is configured to provide the entire top by injection molding. In another embodiment, such as described in DE102005048821 and WO2010 / 085182, the material of the sleeve is folded or otherwise manipulated to engage a ready-made neck element. After the top forming station 2, the container has an open end opposite to the end provided with the top. The capping station 3 is configured to receive the container from the station 2 and screw the threaded cap onto the threaded neck. The filling station 4 is configured to fill the liquid food into the container through the open end of the container and then seal the open end to form a final package containing the liquid food. The filling station 4 can also be configured to sterilize the package before the filling operation.

[0039] Although not shown in Figure 1, any of the stations 1-4 can be replicated to operate in parallel to increase the output of the production line. Each station 1-4 can include one or more machines to perform the processing operations of the station. It is also conceivable that more than one station is operated by a single machine.

[0040] Since many embodiments are available and are well known to those skilled in the art, the structure of the respective stations 1-4 will not be described in detail. The present disclosure relates to the technology of configuring a capping station or machine 3. Thus, the method and capping station described herein can be used for any type of packaging in which a lid is arranged on the neck of the packaging, i.e. regardless of how the packaging body and the packaging neck are manufactured.

[0041] A non-limiting example of a capping machine 3 is schematically shown in Figure 1B The capping machine 3 comprises a first manipulator 31 configured to receive and hold a container 20 produced, for example, by the top forming station 2, and a second manipulator 32 configured to hold and arrange a threaded cap 10 relative to a threaded neck on the container 20 and to rotate the cap 10 so that its threads engage with the threads on the neck. When the cap 10 has been rotated to engage with the neck, the second manipulator releases the cap 10 and the first manipulator releases the container 20, for example, for transport to the filling station 4.

[0042] Figure 1BAlso included is a control device 40, which is configured to control the operation of the capping machine 3. The control device 40 may or may not be part of the machine 3. The control device 40 may be implemented by hardware or a combination of software and hardware. In the example shown, the control device 40 includes a processor circuit 41, a computer memory 42 and a signal interface 43. The processor circuit 41 may, for example, include one or more CPUs ("central processing units"), DSPs ("digital signal processors"), microprocessors, microcontrollers, ASICs ("application-specific integrated circuits"), a combination of discrete analog and / or digital devices, or some other programmable logic devices, such as FPGAs ("field programmable gate arrays"). A control program including computer instructions may be stored in the memory 42 and executed by the processor circuit 41 to perform the methods and procedures described below. The control program may be provided to the control device 40 on a computer-readable medium, which may be a tangible (non-transient) product (e.g., a magnetic medium, an optical disk, a read-only memory, a flash memory, etc.) or a propagation signal. The signal interface 43 may be configured according to conventional practices to receive input signals and provide output signals. In the example shown, the control device 40 is further connected to a feedback device 44 that is configured to generate audible and / or visual feedback to an operator of the machine 3. For example, the feedback device 44 may include one or more of a display, indicator lights, speakers, alarms, etc.

[0043] The operation of the manipulators 31, 32 is controlled by control signals from the control device 40, which are indicated by C1, C2, based on input signals from the respective manipulators, which are indicated by S1, S2. The manipulators 31, 32 can be configured in a variety of different ways to perform their corresponding functions, and will not be described in detail. Examples can be found in the above-mentioned WO2016 / 177750 and WO2007 / 106006.

[0044] Figure 2A-2B 1 is a perspective view of the cover 10 before and after the capping operation. Figure 2A In the embodiment shown, the cap 10 is spaced apart from and aligned with the neck 21 on the container 20. In the example shown, the neck 21 has a threaded portion 22 including three threads 23. Figure 2A Although not shown in FIG. 1 , the cover 20 has three corresponding threads. Figure 2B , the cap 10 has been rotated in the direction of arrow R to engage its threads with the threads 23 on the neck 21 .

[0045] As mentioned in the background section, it is known that the orientation of the threads on the cap relative to the threads on the neck is important to the outcome of the capping operation. Figure 3A-3B(side view of lid 10), the lid 10 is slid onto the neck (end) 21 of the container 20 in two different starting directions. The structures located inside the lid 10 are represented by thin lines. As can be seen, the lid 10 defines an inner cavity 11, which is configured to receive the neck 21. The inner cavity 11 has a threaded portion 12 on the circumferential wall. The threaded portion 12 includes one or more threads 13, which are configured to coincide with one or more threads 23 on the threaded portion 22 of the neck 21. The lid 10 is aligned with the neck 21 by aligning the center / symmetry axis 10a of the lid 10 with the center / symmetry axis 21a of the neck 21.

[0046] Generally, "thread" is a spiral structure wound on a cylinder or cone in the form of a spiral. In the example shown in this article, the lid 10 defines one or more internal (female) threads 13, and the neck 21 defines one or more external (male) threads 23. The corresponding threads 13, 23 have outward thread ends or thread tips 13a, 23a, and the threads 13, 23 are wound into the lid 10 and the neck 21 from the thread ends or thread tips. In the field of liquid food packaging, it is usually that the lid 10 and the neck 21 each have three threads to limit the rotation required when the lid is removed from the packaging. The examples given herein all assume that three threads are provided. However, the present disclosure is applicable to any number (n) of threads, n≥1.

[0047] exist Figure 3A In the embodiment, the cap 10 is arranged so that the threaded end 13a faces the gap between the two threaded ends 23a on the neck 21. Therefore, when the cap 10 is turned in the direction R, the threaded end 13a will slide between the threaded ends 23a, and the thread 23 will be guided along the thread 13 until the cap 10 is firmly engaged with the neck 21.

[0048] exist Figure 3B In the embodiment, the cap 10 is arranged so that the threaded end 13a faces the threaded end 23a on the neck 21. Therefore, when the cap 10 is rotated in the direction R, the threaded end 13a can slide to the left of the threaded end 23A, as shown by the arrow 15, or slide to the right of the threaded end 23A. Figure 3B The orientation of the cap in the filling station 4 results in an unstable capping. This instability may result in the cap being incorrectly mounted on the neck. For example, the cap may be mounted crookedly on the neck. An incorrectly mounted cap may result in an inadequate container seal, damage to the threaded portions on the neck and / or cap, or the final package being too easy to open. Such a final package may need to be discarded. Furthermore, if a leak occurs in the filling station 4, the production line may need to be shut down for cleaning, resulting in an expensive production stoppage.

[0049] The following disclosure relates to the technology of configuring the capping machine 3, and specifically to the technology of determining the correct starting direction of the cap 10 relative to the neck 21 of the container 20, so as to achieve consistent capping performance of the capping machine 3 when the production line is running to produce the final package. The technology is based on the following basic understanding: the search for the correct starting direction of the cap should be designed to test the capping performance under different test directions of the cap relative to the neck, and to find a sequence of adjacent test directions that all produce consistent capping performance. This sequence of adjacent test directions will limit the range of coherent capping directions in which the capping machine may operate normally. Therefore, the correct starting direction is selected from this range and the capping machine is configured accordingly. In the following, the test direction of the cap is also expressed as "starting angle" or "angular position", abbreviated as AP.

[0050] Figure 4 is a bottom plan view toward the cavity 11 of the example cover 10 . Figure 4 The cover 10 will be used to further explain and illustrate the configuration technology. The cover 10 includes three internal threads, which are identical but offset in the circumferential direction of the cover 10. Specifically, as Figure 4 As shown, the thread ends 13a are equidistantly distributed around the periphery of the cap 10. For clarity of illustration, the threads are not shown. In this example of three threads, the angular spacing (angular range) ΔA between adjacent thread ends 13a relative to the central axis 10a of the cap 10 is 120°. Those skilled in the art will appreciate that due to the symmetry of the thread ends 13a, it is only necessary to find the starting direction of the cap 10 within ΔA. Figure 4 A predefined set of test directions within ΔA is also shown by reference symbol [AP]. Each test direction is represented by a dot and corresponds to an angular position AP of the lid relative to the neck on the container. In the illustrated example, 16 points are equiangularly distributed within ΔA, resulting in an angular spacing of 7.5° between adjacent points. Figure 8 In some embodiments described in -10, the test directions are divided into two different categories: PAP (open point) and SAP (solid point).

[0051] like Figure 4 As shown, the cap 10 includes at least one reference element 14 (one is shown in the figure) having a known position relative to the threaded end 13a. The reference element 14 is used to identify the position of the threaded end 13a on the cap 10 for the capping machine 13. Based on the reference element 14, the capping machine 3 can be operated to arrange the cap 10 at any selected angular position between its threaded end 13a and the threaded end 23a on the neck 21 of the container 20. This assumes that the capping machine 3 is also operable to arrange the container 20 at a known orientation of its threaded end 13a. The reference element 14 can be a three-dimensional structure that is configured to cooperate with a corresponding structure on the gripping element of the manipulator 32 ( Figure 1B). For example, the reference element 14 can be a protrusion / depression of a specific shape that matches a depression / protrusion of a corresponding shape on the clamping element, so that the cover reaches a predetermined direction on the clamping element. In another example, the reference element 14 is a visual mark that is detected by the manipulator 32 and used to arrange the cover 10.

[0052] Figure 5 1 is a flow chart of a test procedure 100 that is performed to evaluate the closure performance of a cap in a selected test orientation. Hereinafter, the procedure 100 is also referred to as a cap installation test, abbreviated as CMT. The procedure 100 may be performed by the control device 40 ( Figure 1B ) is implemented, the control device 40 is operated to receive input signals S1, S2 from the capping machine 3 through the signal interface 43 and provide control signals C1, C2 to the capping machine 3. During CMT, the capping machine is operated to perform a plurality of capping operations in the selected test direction and measure the capping performance of each capping operation. The number of capping operations is at least 2, typically at least 5 or 10. Each capping operation consumes one cap and one container. The number of capping operations is weighed between obtaining sufficient data for subsequent capping performance evaluation and limiting the consumption of containers and caps.

[0053] In step 101, the control device 40 waits for the container to be in place for capping. For example, in step 101, the control device 40 may wait until the signal S2 ( Figure 1B ) confirms that the container 20 is located on the manipulator 31. Optionally, the control device 40 may wait for a predetermined period of time in step 101.

[0054] In step 102, the capping machine 3 is operated to arrange the cap 10 in the selected test orientation and rotate the cap 10 to screw it onto the neck 21 of the container 20. The cap 10 is rotated to fully engage the neck 21. Here, "fully engaged" means that the cap 10 is rotated until it meets a predetermined engagement criterion. In some embodiments, the cap is fully engaged with the neck when the torque acting on the cap 10 or equivalently on the container 20 during the rotation of the cap exceeds a predetermined threshold. The torque can be controlled by the manipulator 32 ( Figure 1B ) is given or derived by the instantaneous drive power or drive current of the drive unit in the capping machine 3, or is given by a dedicated torque sensor in the capping machine 3. The signal S1 can indicate the torque.

[0055] In step 103, the capping performance of step 102 is measured or otherwise quantified. Thus, step 103 produces one or more parameter values ​​indicative of the capping performance. In the following examples, the capping performance is given by a parameter "rotational path length" (path length), which is the total rotation of the cap from a selected test orientation to its full engagement. For example, the path length may be given in degrees (°) or any equivalent unit. In the following examples, if the cap fails to fully engage when the path length reaches a maximum length value (MLV), the path length is set to a predetermined MLV. In Figure 1B In the example in FIG. 4 , the path length is given by a signal S1 which may be generated by a drive unit in the manipulator 32 described above or by a dedicated rotation sensor in the capping machine.

[0056] It may be noted that the capping performance may be quantified in other ways in step 103. In one example, the capping performance is evaluated by computer vision based on digital images or videos of the cap 10 and the neck 21 during the capping operation and graded according to a predefined scale. In another example, the cap is rotated for a predetermined period of time or until it is fully engaged in step 102, and the capping performance is derived from the maximum torque obtained within the predetermined period of time.

[0057] In step 105, the control device checks whether all capping operations have been performed. If not, the control device returns 106 to step 101 to wait for the next container to be in position for capping. If all capping operations have been performed, the CTM 100 ends 107.

[0058] As indicated by the dashed line, the CMT 100 may include a step 104 that ends the CTM 100 if the path length during the capping operation is too long. Figure 11-12 The rapid termination of step 104 is discussed further.

[0059] Figure 6 is a graph of measurement data obtained by CMT in the test direction ("starting angle") in the angular range of 0° to 120° in steps of 10°. For each angle, CMT includes 10 capping operations. The measurement data are given in degrees (°) as the rotation path length. The measurement data can be divided into three different areas 61, 62, 63, as indicated by the dotted lines. It can be noted that the starting angle 0° is equivalent to the starting angle 120° (see Figure 4 ), so region 61' is redundant. In region 61, the path length for each test direction is bimodal, with some capping operations having a path length of about 580° and some capping operations having a path length of about 700°. Figure 3BAs shown, region 61 exhibits unstable capping performance. The bimodal distribution in region 61 is likely to occur when the end of the thread on the cap and the neck meet. In region 62, the path length has another bimodal distribution, in which a set of path lengths is close to or at the maximum length value (MLV), in this case 950°. Therefore, region 62 also exhibits unstable capping performance. In the example shown, some capping operations in each test direction in region 62 failed to fully engage the cap with the neck. This may occur if the threads on the cap "engage" the threads on the neck. It is also believed that certain shapes of the top of the container may contribute to the appearance of region 62, for example, when the cap is tightened to the neck, the top is prone to deformation. This deformation may cause the path length to be extended. On the other hand, region 63 exhibits stable capping performance. In the example shown, region 63 spans a starting angle of 10°-40°.

[0060] from Figure 6 It can be seen why the prior art described in the background section may fail. If poor capping performance is detected for a starting angle in region 61, then a starting angle offset of 60° will eventually appear in region 62. If poor capping performance is detected for a starting angle in region 62, then a starting angle offset of 60° will eventually appear in region 61. Applicants have developed a completely different approach, namely actively searching for a sequence of adjacent angular positions (APs) that result in stable capping performance, i.e. actively identifying at least a portion of stable region 63. In Figure 6 In the example of FIG. 6 , region 63 includes a sequence of four such adjacent APs, at 10°, 20°, 30° and 40°. The sequence should include at least two adjacent APs, and preferably at least three adjacent APs, to increase the certainty that a stable region 63 has been found. It should be noted that an AP with acceptable performance is searched for in a set of predefined APs (test directions). This set is denoted "predefined set" and is designated as [AP] in the following. Reference Figure 6 The test results in [AP] show that the number of predefined APs is 12, extending from 0° to 110° at intervals of 10°. Preferably, the predefined APs in [AP] span the angle range ΔA ( Figure 4 ) to cover the full range of relevant test directions. The predefined APs may be equally spaced within ΔA or unequally spaced. Equidistant distribution (equal angular spacing) is considered to be more effective in detecting stable regions 63. Each AP corresponds to a direction of the lid, and a "sequence of adjacent APs" means a sequence of APs corresponding to spatially adjacent directions of the lid. To emphasize the spatial relationship, "adjacent APs" is used synonymously with "spatially adjacent APs" in this article. Figure 6In the example of , AP = 10° and AP = 30° are spatially adjacent to AP = 20°. Note that the angular position wraps around at the end of the angular range, since AP = 120° is equivalent to AP = 0°. Figure 6 In the figure, AP=100° and AP=0° are spatially adjacent to AP=110°.

[0061] Figure 7 2 is a flow chart of an example configuration method 200 according to some embodiments. The method 200 is performed whenever the capping machine needs to be configured, such as when the capping machine is started or restarted, after service or maintenance, when a new type of container / closure is to be processed, etc. The method 200 can be performed by the control device 40 ( Figure 1B ) is implemented. In step 201, an AP is selected from the above predefined set ([AP]). The APs in [AP] are sorted, and step 201 selects an AP based on the sorting. Therefore, step 201 involves selecting APs from [AP] in order. As will be seen, step 201 is repeated until a termination condition is met in step 203 (below). For example, according to Figure 5 , after step 201, method 200 continues to perform CMT 100 at the selected AP. Therefore, the parameter value generated by CMT 100 indicates the capping performance of multiple capping operations at the selected AP. In step 202, the capping performance is evaluated to detect consistent capping performance, referred to as CCP. As used herein, "consistent capping performance" means that the parameter value generated by CMT 100 has sufficiently low variability. In the following description, the parameter value is the path length, and the CCP is detected when the variability of the path length is below a variability threshold. The variability can be given by any suitable metric, including but not limited to variance, standard deviation, range, interquartile range, coefficient of variation, sum of absolute deviations, mean absolute deviation, etc. If step 202 fails to detect a CCP, the method returns to step 201, where the next AP is selected from [AP]. If step 202 detects a CCP, the method continues to step 203, where a termination condition is evaluated. The termination condition requires that a CCP be detected for a sequence of N (where N≥2) spatially adjacent APs. As will be further described below, the termination condition may include additional criteria. If the termination condition is not met, the method returns to step 201. If it is met, the method proceeds to step 204, where the capping machine is configured by setting an operating AP to be used as a starting angle for capping when the capping machine is running in production. The operating AP is set relative to a sequence of N spatially adjacent APs, typically within a range of APs spanned by the sequence. For example, the operating AP may be set to the average or median of the APs in the sequence, or to one of the APs in the sequence.

[0062] It may be noted that the ordering of the APs in the predefined set [AP] defines the search order of method 200 and thereby defines the order in which the APs are searched for detecting CCPs. In one example, the APs are arranged in [AP] in a random order. In another example, the APs are arranged in [AP] to represent consecutive spatial directions of the cover. This may be achieved by increasing or decreasing the magnitude of the arranged APs, e.g. Figure 6 However, the sequencing can start from another AP and consider the winding AP, such as Figure 6 30°, ..., 110°, 0°, ..., 20°.

[0063] In some embodiments, step 203 may also require that the sequence of N spatially adjacent APs span a predefined width (angle sub-range) to meet the termination condition. This will increase the number of stable regions ( Figure 6 63) in the certainty. The predefined width can be set in the range of about 5%-50% of the angle range ΔA. In some embodiments, the predefined width is set in the range of 10%-40%. The predefined width should be set smaller than the expected width of the stable area. Figure 6 In the example shown, the width is approximately 40°.

[0064] Each CMT executed by method 200 consumes a container and a lid. Therefore, it is best to minimize the number of CMTs. This can be achieved through clever sorting and use of predefined sets ([AP]) to achieve a more efficient search for stable regions. In some embodiments, [AP] is defined as a first subset of primary angular positions (PAPs) and a second subset of secondary angular positions (SAPs) dispersed among the PAPs. Figure 7 In the context of , step 201 is implemented to sequentially select APs among the PAPs in the first subset. When a CCP is detected in step 202, at least one SAP is selected from the second subset, the selected SAP being spatially adjacent to the selected PAP, and then CMT is performed on each selected SAP. Then, if a CCP is detected at each selected SAP, step 203 terminates the method, otherwise the method returns to step 201 to select the next PAP from the first subset. The search method is graphically illustrated in Figure 8 In the figure, the hollow dots represent PAP and the solid dots represent SAP. Figure 8 The points in correspond to Figure 4 The first and second subsets are designated by [PAP] and [SAP], respectively. In the example shown, the APs are equally spaced within ΔA, and each PAP has two adjacent SAPs; one smaller and one larger. Figure 8In the figure, solid arrows 81-87 represent the order of PAPs in [PAP], and dashed arrows with apostrophes (') and double apostrophes (") represent adjacent SAPs associated with the corresponding PAPs. In the example shown, PAP=0° is the first selected AP. If a CCP of PAP=0° is detected, a corresponding CMT is performed on at least one of SAP=7.5° and SAP 112.5°, as shown by arrows 80', 80". If a CCP of SAP is not detected, PAP=30° is selected, and so on.

[0065] Based on the above, it can be realized that the choice of SAP depends on the CCP detection of the PAP. This means that fewer CMTs need to be performed when searching for ΔA to detect stable areas. It is currently believed that based on the configuration of the capper, container and lid, there should be 4-12 PAPs in the predefined set to provide sufficient ΔA coverage. In the example of ΔA=120° and equidistant PAPs, this corresponds to a spacing of 10°-30° between spatially adjacent PAPs. Figure 8 The spacing between spatially adjacent PAPs was 15°.

[0066] exist Figure 8 In the example of , there is one SAP between each pair of spatially adjacent PAPs, so each PAP has two adjacent SAPs, one on each side. It is conceivable that there is more than one adjacent SAP on one or both sides of the corresponding PAP. The SAPs may or may not be evenly distributed among the PAPs.

[0067] It may be advantageous to match the distribution of PAPs and SAPs to the termination condition. For example, if the termination condition specifies that N = 3, i.e., CCPs should be detected for three spatially adjacent APs, then it may be advantageous to have one SAP between each pair of PAPs, e.g. Figure 8 If the termination condition specifies N = 5, then it may be advantageous to have two SAPs between each pair of PAPs. In general, if N ≥ 3, efficient detection of stable regions can be achieved by defining the termination condition as requiring the detection of CCPs at a PAP and at one or more SAPs on either side of the PAP. Figure 8 In the example of , this corresponds to detecting a CCP at the hollow dot and at two solid dots indicated by dashed arrows starting from the hollow dot.

[0068] from Figure 8 It is understood that in [PAP], the PAPs do not have to be strictly ordered by magnitude. Figure 8The ordering shown in is intended to further speed up the search for stable regions. According to this ordering, [PAP] includes a first subsequence SS1 of PAPs sorted by amplitude, and a second subsequence SS2 of PAPs interleaved with the PAPs of SS1 and sorted by amplitude, wherein SS2 is located after SS1 in [PAP]. As shown by the solid arrows 81-87, this results in two consecutive scans ΔA at different PAPs. In practice, the first scan skips every second PAP, and then a second scan is performed on the skipped PAPs. In a variant, more than one PAP may be skipped in the first scan. It is currently believed that the "jumps" between PAPs in the first scan (derived from the PAP spacing in SS1) should be smaller than the expected width of the stable region.

[0069] like Figure 8 As shown, the PAPs in both SS1 and SS2 are sorted by increasing amplitude. This means that the first and second scans are performed in the same direction across ΔA. Although the root cause is not fully understood, it has been found that this can speed up the search for stable regions. The same is true when the PAPs in both SS1 and SS2 are sorted by decreasing amplitude.

[0070] It is worth noting that the splitting of [PAP] into SS1 and SS2 is an optional feature. Adequate results may also be achieved with other orderings of [PAP], such as increasing or decreasing amplitudes, random ordering, etc.

[0071] Fig. 9 2 is a flow chart of a configuration method 200' for implementing the aforementioned PAP and SAP. The method 200' may be implemented by the control device 40 ( Figure 1B ) is executed. In step 201A, Figure 7 , a PAP is selected from [PAP] based on its ranking. The method then continues to execute CMT 100 at the selected PAP. Step 202 evaluates the parameter values ​​measured in the CMT to detect a CCP. If step 202 fails to detect a CCP, the method returns to step 201A, where the next PAP is selected from [PAP]. As shown, step 210 can be performed to check whether there are more PAPs in [PAP], and if all PAPs have been processed, an alarm is generated (step 211). The feedback device 44 ( Figure 1B) to generate an alarm. If step 202 detects a CCP, the method proceeds to step 201B. In step 201B, a SAP is selected from [SAP]. The selected SAP is spatially adjacent to the last selected PAP. The method then continues to perform CMT 100 at the selected SAP. Step 202 evaluates the parameter values ​​measured in the latest CMT to detect a CCP. If step 202 fails to detect a CCP, the method returns to step 201A. If step 202 detects a CCP, the method proceeds to step 203' to check whether a sufficient number N of spatially adjacent APs have been found for CCPs. If not, step 203' proceeds to step 201B, where another spatially adjacent SAP is selected from [SAP]. When a sufficient number N of adjacent APs have been found for CCPs, step 203' proceeds to step 204. In step 204, the capping machine is configured as described above. It can be appreciated that step 203' corresponds to the evaluation of a termination condition. As shown, method 200' may also include a verification step 400 performed after step 203'. If the verification fails, the method returns to step 201A. If the verification succeeds, the method proceeds to step 204. Step 400 also corresponds to the evaluation of the termination condition, which will be referred to below. Fig.13 -14 further described.

[0072] Fig. 10A The operation of method 200' is further illustrated in Figure 6 It is related to the measured data in . It is assumed here that the spacing of PAPs is 30°, and the order in [PAP] is as follows: 0°, 30°, 60°, 90°, 15°, 45°, 75°, 105°, and each PAP has two adjacent SAPs, offset by -10° and +10°, respectively. It is also assumed that the termination condition requires three spatially adjacent APs to produce a CCP (N=3). At PAP=0° (AP1), CMT leads to a bimodal distribution of path lengths, resulting in variability exceeding the variability threshold. Therefore, no CCP is found at PAP=0°. Next, as indicated by the solid arrow, CMT is performed at PAP=30° (AP2). Here, the variability is below the variability threshold and a CCP is found. Therefore, CMT is performed at SAP=20° (AP2'). Here, a CCP is also found. Since N=3, CMT is also performed at SAP=40°(AP2"). Since CCPs are found at AP2, AP2' and AP2", a stable region has been detected and the operating AP (OAP) is set within the stable region, in this example at 30°(AP2).

[0073] Fig. 10B The method 200' is shown with respect to Figure 6Another example of the operation of the measurement data in . Here, it is assumed that the PAPs have the following order in [PAP]: 50°, 80°, 110°, 20°, 65°, 95°, 5°, 35°, and each PAP has two adjacent SAPs, offset by -10° and +10°, respectively. It is also assumed that the termination condition requires N=3. As shown in the figure, no CCP is found at PAP=50° (AP1), PAP=80° (AP2), or PAP=110° (AP3). A CCP is found at PAP=20° (AP4), and CCPs are also found at SAP=10° (AP4') and SAP=30° (AP4"). Since CCPs are found at AP4, AP4', and AP4", a stable region is detected and the OAP is set within the stable region, which is 20° (AP4) in this example.

[0074] Back to Figure 5 , CMT 100 may include a fast termination step 104, which is used to further speed up the search for the stable area and reduce the consumption of containers and lids. Step 104 checks whether the corresponding path length for the capping operation determined by step 103 exceeds a length threshold TH1. If so, the CMT is terminated. The principle behind step 104 is that if the selected AP results in a path length that is too long, it cannot be in the stable area. The position of TH1 is Fig.11 The skilled person recognizes that the path length for a proper capping operation itself varies with the capping direction. Fig.11 TH1 should be well above BL and well below the maximum length value (MLV) assigned to the unengaged lid.

[0075] As an alternative to the fast determination step 104, the evaluation step 202 in the configuration method 200, 200' can apply TH1 when detecting CCP by requiring that all measured path lengths are below TH1. Therefore, in one example, CCP is detected only when the variability of the path lengths measured at the selected AP is below the variability threshold and all measured path lengths at the selected AP are below the length threshold TH1.

[0076] In some embodiments, TH1 is given as a predefined value. In other embodiments, TH1 is given by Fig.12 The initial calibration procedure or operation 300 shown in FIG. 300 may be determined by the control device 40 ( Figure 1B). In step 301, an AP is selected from a predefined set [AP]. After step 301, a limited CMT 100 is performed at the selected AP. In order to limit the consumption of containers and lids, the limited CMT 100 contains a smaller number of capping operations than the CMT 100 performed during the method 200, 200'. For example, the limited CMT 100 may involve 1-3 capping operations. Steps 301 and 100 are repeated, through step 302, until all APs in [AP] or a predefined subset of [AP] are selected. Then, in step 303, TH1 is determined based on the path length measured for the corresponding capping operation during the limited CMT (see Figure 5 Step 303 can be implemented in a variety of different ways to position TH1 between BL and MLV ( Fig.12 ), for example through histogram analysis.

[0077] The process 300 is to implement an initial calibration operation in which the capper is operated to perform at least one capping operation at each AP in [AP] or a subset thereof, and a length threshold (TH1) is determined based on the capping path length during the initial calibration operation.

[0078] Fig.13 It can be used as Fig. 9 Flowchart of an example of a verification 400 performed as part of the method 200, 200'. The verification 400 is optional and may be performed to increase the certainty of detecting a stable region. Fig.14A , which is a graph of the path length measured as a function of AP. Therefore, if the corresponding CMT is performed at AP=20°, AP=30° and AP=40°, the final distribution of path length is represented by the solid rectangles 71. The path length variability at each rectangle 71 is low and stable regions 70 can be identified by methods 200, 200'. Applicants have discovered that there may be potential instabilities in the capping performance at the AP, which means that the instability may not show up in the measured path length, for example, if the number of capping operations is small relative to the probability of instability occurring. Go to Fig. 14B , AP=110° indicates potential instability, where the solid rectangle 71 represents the measured path length, and the hollow rectangle 71' represents the path length that would also be measured if the number of capping operations increases. As shown in rectangle 71, due to the low variability of the path length measured at AP=90°, AP=100°, and AP=110°, the method 200, 200' may erroneously identify the stable region 70. The verification 400 can avoid this problem.

[0079] exist Fig.13In the example of FIG. 4 , verification 400 includes a step 401 of obtaining the path length of the AP sequence that leads to the CCP, i.e., the AP that has been identified as being potentially contained in the stable region. For example, assuming that the measured path length has been stored in the memory 42 during the CMT 10, the path length can be retrieved from the memory 42 in step 401. In step 402, a variability constraint is obtained, for example, from the memory 42. The variability constraint can be predefined and Figures 14A-14B Specified by ΔL in step 401. The variability constraint ΔL defines the maximum allowed variability or spread of the measured path lengths obtained in step 401. The variability may be given by any suitable metric and may have a predetermined value. In step 403, the measured path lengths are collectively evaluated with respect to the variability constraint. If the variability of the measured path lengths is within the variability constraint, step 404 proceeds to step 405 and the validation is deemed successful. Otherwise, step 404 proceeds to step 406 and the validation is deemed failed. Fig. 9 As shown, the result of verification 400 may affect whether the termination condition is met. Fig.14A , verification 400 will succeed and region 70 will be considered a stable region. Fig. 14B , verification 400 will fail and region 70 will not be considered a stable region.

[0080] like Figures 14A-14B As shown, the variability constraint ΔL can be set based on the changing baseline BL, which is known and given by the thread structure on the lid and the container. Specifically, ΔL can be set to allow for the known changes in BL so that the required number (N) of spatially adjacent APs can be detected within the stable region.

[0081] The present disclosure is not limited to containers made from a sleeve of sheet material, but is applicable to any container that includes a threaded neck configured to engage a threaded lid.

Claims

1. A computer-implemented method for configuring a capping machine (3), the configured capping machine being operable to place a cap (10) in a given angular position (OAP) relative to a neck (21) on a container (20), and to rotate the cap (10) relative to the neck (21) so that a threaded portion (12) of the cap (10) is fully engaged with a corresponding threaded portion (22) of the neck (21), the method comprising: sequentially selecting (201) angular positions from a predefined set ([AP]) of angular positions of the cap (10) until a termination condition (203) is satisfied, wherein the angular positions in the predefined set ([AP]) correspond to different orientations of the threaded portion (12) of the cap (10) relative to the threaded portion (22) of the neck (21), For each selected angular position, operating (100) the capping machine (3) to perform a plurality of capping operations, wherein each of a plurality of lids (10) is arranged at the selected angular position and rotated to fully engage a corresponding neck (21) on a corresponding container (20), and evaluating (202) consistent capping performance of the plurality of capping operations at the selected angular positions, wherein the termination condition requires detection of the consistent capping performance of a sequence of adjacent angular positions corresponding to a sequence of spatially adjacent directions of the threaded portion (12) of the cap (10) relative to the threaded portion (22) of the neck (21), and The method further comprises configuring (204) the capping machine (3) by setting the given angular position (OAP) relative to the sequence of adjacent angular positions.

2. A method according to claim 1, wherein the angular positions in the predefined set ([AP]) span a predefined angular range (ΔA) corresponding to the angular spacing of one or more threads (12) on the cover (10). 3 . The method according to claim 2 , wherein the angular positions in the predefined set ([AP]) are mapped to the predefined angular range (ΔA) with equal angular spacing.

4. The method according to claim 2 or 3, wherein the sequence of adjacent angular positions spans an angular sub-range of 5%-50% or 10%-40% of the predefined angular range (ΔA).

5. A method according to any one of the preceding claims, wherein: The predefined set ([AP]) comprises a first subset of primary angular positions ([PAP]) and a second subset of secondary angular positions ([SAP]) dispersed between the primary angular positions, wherein the selected angular positions are selected sequentially among the primary angular positions in the first subset ([PAP]), the method further comprising: selecting (201B) at least one secondary angular position from the second subset ([SAP]) when the consistent capping performance is detected at the selected angular position, the at least one secondary angular position being spatially adjacent to the selected angular position, and for each selected secondary angular position, operating (100) the capping machine (3) to perform a further plurality of capping operations and evaluating (202) the consistent capping performance of the further plurality of capping operations at the selected secondary angular position, Wherein, in order to detect the consistent capping performance of the sequence of adjacent angular positions, the termination condition (204) requires the consistent capping performance at each selected secondary angular position to be detected.

6. A method according to claim 5, wherein the first subset ([PAP]) comprises an ordered sequence of principal angular positions, and wherein the selected angular positions are selected sequentially from the first subset according to the ordered sequence of principal angular positions.

7. A method according to claim 6, wherein the first subset ([PAP]) includes a first subsequence (SS1) of main angular positions sorted by amplitude, and a second subsequence (SS2) of main angular positions interleaved with the main angular positions of the first subsequence (SS1) and sorted by amplitude, wherein the second subsequence (SS2) follows the first subsequence (SS1) in the first subset ([PAP]).

8. The method according to any one of claims 5-7, wherein the predefined set ([AP]) consists of 4 to 12 principal angular positions.

9. Method according to any one of claims 5-8, wherein the second subset ([SAP]) comprises at least one secondary angular position between each pair of spatially adjacent primary angular positions in the first subset ([PAP]).

10. A method according to any one of claims 5-9, wherein the termination condition (203) requires detection of the consistent capping performance at one or more selected secondary angular positions less than the selected angular position and at one or more selected secondary angular positions greater than the selected angular position.

11. The method according to any one of the preceding claims, further comprising: An input signal (S1) indicative of a rotational path length of the plurality of caps (10) is acquired during the plurality of capping operations, wherein the rotational path length (202) is evaluated to detect the consistent capping performance.

12. The method of claim 11, wherein the consistent capping performance is detected when a variability in the rotational path length is below a variability threshold.

13. The method of claim 12, wherein the consistent capping performance is further detected when all rotational path lengths are below a length threshold (TH1).

14. The method according to claim 11 or 12, further comprising: While operating the capping machine to perform the plurality of capping operations at the selected angular position, evaluating (104) the rotational path length of the cap (10) relative to a length threshold (TH1), stopping the plurality of capping operations when at least one rotational cap length exceeds the length threshold (TH1), and sequentially selecting another angular position from the predefined set ([AP]).

15. The method according to any one of claims 11 to 14, further comprising: The rotational path lengths of the plurality of lids (10) during the plurality of capping operations are collectively evaluated (403) relative to a variability constraint (ΔL) for each angular position in the sequence of adjacent angular positions, and wherein the termination condition (204) also requires that the variability constraint be satisfied.

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