LEJON, Hanna (Fagottgatan 5, Råå, S-25271, SE)
ELGEBRANT, Johan (Engelska gången 8, Helsingborg, S-254 51, SE)
SOERENSEN, Karsten (Östen Undensgata 180, Lund, S-22762, SE)
ANDERSSON, Bengt (Västervångsgatan 22, Malmö, S-21774, SE)
LEJON, Hanna (Fagottgatan 5, Råå, S-25271, SE)
ELGEBRANT, Johan (Engelska gången 8, Helsingborg, S-254 51, SE)
SOERENSEN, Karsten (Östen Undensgata 180, Lund, S-22762, SE)
| CLAIMS 1. A sheet of packaging material comprising a plurality of magnetisable portions thereon comprising at least three magnetisable portions per package to be formed from the packaging material, wherein said at least three magnetisable portions, for each package to be formed, provide a magnetic mark carrying a magnetic field pattern such that position and orientation information related to finishing of the respective package is provided. 2. The sheet according to claim 1, wherein the forming comprises forming a tubular intermediate product from the sheet of packaging material, and wherein the magnetic mark is applied to control skew of the material. 3. The sheet according to any of claim 1 or 2, wherein the forming comprises forming a tubular intermediate product from the material, and wherein the magnetic mark defines an overlap upon forming the tubular intermediate product such that a desired diameter of the tubular intermediate product is controllable. 4. The sheet according to any of claims 1 to 3, wherein the forming comprises forming a tubular intermediate product from the material, and wherein the magnetic mark defines at least one position for determining a twist of the tube when forming the final package. 5. The sheet according to any of claims 1 to 4, wherein the magnetic mark defines at least one position for folding of the final package. 6. The sheet according to any of claims 1 to 5, wherein the magnetic mark defines at least one position for sealing of the final package. 7. The sheet according to any of claims 1 to 6, wherein the magnetic mark defines at least one position for determining mutual positions of a first web of the material and a second web of the material when splicing the first and second webs. 8. A method for finishing packages from a sheet of packaging material comprising a plurality of magnetisable portions thereon and comprising at least three magnetisable portions per package to be formed from the sheet, wherein said at least three of the magnetisable portions, for each package to be formed, provide a magnetic mark carrying a magnetic field pattern, the method comprising reading position information from the magnetic marks; forming the sheet into a tubular intermediate product; filling the tubular intermediate product with content; and sealing the tubular intermediate product, wherein said forming and sealing is performed based on position information read from the magnetic mark. 9. The method according to claim 8, wherein an overlap ot the formed tubular intermediate product is controlled based on a reading of the magnetic marks such that a desired diameter of the tubular intermediate product is provided. 10. The material according to any of claim 8 or 9, wherein any twist of the formed tubular intermediate product is controlled based on a reading of the magnetic marks. |
Technical field
The present invention relates to a packaging material, and a method for finishing packages from a web of such a packaging material.
Background Within packaging technology where a packaging container is formed from a packaging laminate, it is known to provide the packaging laminate as a web which prior or during packaging is formed to the packaging container. Guiding marks, e.g. for optical reading has been provided to guide operations when finishing the package, such as forming, sealing, folding, etc. Such guiding marks are sometimes referred to as register marks. The register mark for optical reading is provided during printing of the packing laminate, where e.g. decoration or product information is printed on the packaging laminate. A problem with such register marks is that they consume a non-negligible area of what becomes the exterior of the package. A further problem is that such a register mark has to rely on the printing being well aligned with other operations performed on the web. It is therefore a desire to provide an improved provision of marking of web of packaging laminate to enable proper finishing of the packages.
Summary
The present invention is based on the understanding that magnetic marking can be provided on a packaging laminate. The understanding further comprises that alignment of operations for finishing a package from such a packaging laminate can greatly improve accuracy and reliability of finishing operations.
According to a first aspect, there is provided a packaging material comprising a plurality of magnetisable portions thereon and comprising at least three magnetisable portions per package to be formed from the packaging material, wherein the at least three of the magnetisable portions, for each package to be formed, provides a magnetic mark carrying a magnetic field pattern such that position and orientation information related to finishing of the respective package is provided. In a preferred practical embodiment of the invention a web of the packaging material comprises three magnetic marks per package to be formed from the packaging material, said three magnetic marks are carrying a magnetic field pattern which may be used to detect and control skew of the packaging material as well as to define an overlap upon forming a tubular intermediate product from the packaging material. In other words, unacceptable skew and/or overlap of the formed tubular product can safely and simply be detected and discarded at a time before the tubular product is filled with its intended product, such as a liquid food. The magnetic marks may define a position for cutting the web into the parts thereof for forming respective package, and/or define a position and orientation for forming of the package.
The forming may comprise forming a tubular intermediate product from the material, and the magnetic marks can be applied to control skew of the material, define an overlap upon forming the tubular intermediate product such that a desired diameter of the tubular intermediate product is controllable, and/or define at least one position for determining a twist of the tube when forming the final package.
The magnetic marks may define at least one position for folding of the final package, and/or define at least one position for sealing of the final package.
The magnetic mark may define at least one position for determining mutual positions of a first web of the material and a second web of the material when splicing the first and second webs. According to a second aspect, there is provided a method for finishing packages from a web of packaging material comprising a plurality of magnetisable portions thereon and comprising at least three magnetisable portions per package to be formed from the packaging laminate, wherein at least three of the magnetisable portions, for each package to be formed, provides a magnetic mark carrying a magnetic field pattern, the method comprising reading position information from the magnetic marks; cutting the web into parts to form the packages; forming the parts into an intermediate product; filling the package with content; and sealing the package, wherein the any of the cutting, forming, and sealing is performed based on position information read from the magnetic marks. The method may further comprise, after the cutting and before the forming, moving the respective part from the position of cutting to a position of forming, wherein position and orientation information of at least two of the magnetic marks is used for aligning the part into the position of forming. The forming may comprise forming a tubular intermediate product from the material. The method may also comprise controlling skew of the material based on a reading of the magnetic marks. The method may also comprise controlling the overlap of the tubular intermediate product based on a reading of the magnetic marks such that a desired diameter of the tubular intermediate product is provided. The method may also comprise controlling twist of the tube when forming the final package based on a reading of the magnetic marks.
The reading may be performed at a position where the material has any of no movement or constant movement during reading, and control of the movement at that position during reading may comprise providing a slack of the material before that position.
The method may further comprise moulding a cap portion, wherein aligning of a moulding tool is based on position information read from a magnetic mark. The cap portion may be moulded at a recess of the part of the web, wherein a position of the recess is defined by a magnetic mark dedicated and aligned with the recess.
Brief description of drawings
Fig. 1 schematically illustrates a process of finishing a package according to an embodiment.
Figs 2a and 2b schematically illustrates utilizing the magnetic marks for aligning forming of a tubular intermediate product upon finishing a package according to an embodiment.
Fig. 3 schematically illustrates an approach for controlling speed at a position for reading a magnetic mark.
Detailed description
Fig. 1 schematically illustrates an exemplary process of finishing a package for food or liquids. 1. A web 100 of packaging material, such as a laminate, comprising a plurality of magnetisable portions 102 is used. The web 100 comprises four magnetisable portions 102 per package to be formed from the packaging material. The magnetisable portions carry magnetic marks indicating positions on the web and these marks are used for aligning finishing operations. Further magnetic marks can be provided to support further finishing operations, but the function of the four magnetic marks will be explicitly discussed below. At least one of the magnetisable portions, for each package to be formed, provides a magnetic mark carrying a magnetic field pattern for aid of cutting the part 105 of the packaging material to form the package from the web. Thus, the magnetic mark(s) 102 can define positions 103, 104 for cutting the web into the parts thereof for forming respective package. For the transversal cut 104, in principle only one mark is needed. However, further marks can be used for improving accuracy, e.g. by applying a decision algorithm, e.g. averaging or compensation for skew, from several mark readings. Similar applies for the longitudinal cut 103. The part 105 is transported from the cutting operation position to a package forming position. Here, at least two of the marks are preferably used to be able to determine both position and orientation of the part 105. At a position for forming the package, the magnetic marks 102 defines a position for forming of the package. The forming can comprise forming a tubular intermediate product 106 from the web, and the magnetic marks 102 can then define overlapping 107 upon forming the tubular intermediate product 106 such that a desired diameter of the tubular intermediate product 106 is accurately controllable, whereby the final volume of the package stays within desired boundaries. Here, utilization of the four marks will enable full control of position, skew and overlap when forming the tubular intermediate product 106. The magnetic marks can also define at least one position for folding of the final package. An example is where the magnetic mark is aligned with crease lines formed at the web, and the folding should be aligned with the crease lines. The magnetic mark can also define at least one position for sealing of the final package. The sealing can be heat and mechanical operation at an end of the tube, and/or moulding a plastic opening part at an end of the tube.
The process illustrated in Fig. 1 is intended to schematically give understanding of a method for finishing packages from the web 100. The tools, mechanisms, and other means for performing the operations are not illustrated not to obscure the illustrated flow of finishing the package. During the process, reading of position information from the at least one magnetic mark as elucidated above is performed at least once, but is preferably performed in each operation where any alignment of the parts is needed. As the web 100 is fed for finishing, there is in the illustrated embodiment first performed an operation of cutting the web into parts to form the packages. Alignment of the cutting is then preferably made based on position information from at least one magnetic mark. This has an advantage compared to e.g. tracking a border of the web, as the border may not be in such accurate alignment with e.g. prepared features on the web, and does not give any information of the position in the longitudinal direction. Upon forming the parts into an intermediate product 106, the magnetic mark(s) may be used to ensure that the size and shape of the intermediate product 106 becomes as desired. Further operations, i.e. filling the package with content and sealing the package can be performed based on position information of the magnetic mark(s) in a similar way, if needed. Preferably, the method further comprises, after the cutting and before the forming, moving the respective part from the position of cutting to a position of forming. Here, the parts can become misaligned.
However, by using position information of the magnetic mark for aligning the part into the position, forming can be made with improved accuracy and reliability. The forming can comprise a number of sub-steps. These sub-steps can comprise [har behδver jag en noggrannare beskrivning av att forma en paket pa en plugg, och hur man kan anvanda market for det], wherein the sub-step of [...] can benefit from acquiring accurate position information from any of the magnetic marks.
The method can further comprise e.g. moulding a cap portion, wherein aligning of a moulding tool is based on position information read from the magnetic mark. For example, the cap portion can be moulded at a recess of the part of the web, wherein a position of the recess is defined by a magnetic mark dedicated and aligned with the recess.
As an alternative, the web may be provided with magnetic mark(s) upon the cutting operation, which then will be aligned with the cutout part. This/these mark(s) is/are then used for the following operations, as elucidated above.
Figs 2a and 2b schematically illustrates utilizing the magnetic marks for aligning forming of a tubular intermediate product upon finishing a package according to an embodiment, where Fig. 2a illustrates the part 105 as distributed from cutting to forming operations, and Fig. 2b illustrates the part 105 being formed to a tubular intermediate product 106. The exemplary positions of the four magnetisable portions 102 and their magnetic marks on the part 105 of the packaging material provides an advantageous way of controlling an overlap 107 of the tubular intermediate product 106, as illustrated in Fig. 2b. Here, the marks are positioned close to the border of the part 105 to overlap, but can also be positioned at a predetermined distance from the border. However, for illustrative purposes, and for the easier understanding of the principle, the alignment of the overlap will be discussed in light of the illustrated example. Upon forming the tubular intermediate product 106, the magnetic marks 102 are brought into line with each other as illustrated in Fig. 2b. Thereby, as the magnetic marks 102 are accurately assigned, and it is feasible to measure the marks to control the forming of the tube 106, the tubular intermediate product 106 will have the intended shape, and thus the intended volume. Thus, fewer packages need to be discarded due to being misshaped or having wrong volume. Further, skew of the part 105 upon forming the tubular intermediate product can be controlled. In case the skew is too large, the package would have to be discarded, but with the accurate control that now is enabled, fewer packages need to be discarded for that reason.A further position information, that the magnetisable portion can hold, is magnetic field position marks at ends of a web of the packaging material, i.e. beginning of web and/or end of web, such that, at splicing of the webs, the splice is enabled to be aligned.
A further position information is positioning of an optical mark, which may beneficial compatibility for packaging machines having either optical reading or magnetic reading of positioning information. Preferably, the position of the spot holding this information is positioned similar to the optical mark, but on the side that is intended to become the inside of the package. Since the optical marks normally is provided on the part intended to form the bottom of the package, the corresponding magnetisable portion is positioned accordingly. A magnetic field mark at this magnetisable portion is thus enabled to provide the similar information as the optical mark, and the optical reader of a packaging machine can thus simply be replaced with a magnetic reader. In practise, no optical mark is thus necessary if the optical readers are replaced by magnetic readers, and the magnetic mark takes the place of the optical mark as described above. In that case, the compatibility lies in the sense of the same mounting position of the readers in the packaging machine. A further position information can be for a print for the package outside. This position information can be beneficial for ensuring proper alignment of the print with the package.
Upon making the magnetic field mark, it can be beneficial that the means for reading the magnetic field mark, e.g. a coil arrangement, has no or little relative movement, or at least an approximately constant relative movement to the magnetic field mark. This can be achieved for example by integrating the reading means in e.g. rolls for conveying the web, wherein there is no relative movement since the periphery of the rolls and the web moves by the same speed in the same direction. Another way of achieving no or little relative movement, or at least an approximately constant relative movement to the magnetic field mark is to control the movement at the position of the reading. This can be done by having a slacking portion of the web before reading position such that speed at this position can be controlled irrespective of the speed of the web before that position, as illustrated in Fig. 3. Fig. 3 schematically illustrates an approach for controlling speed at the position of reading 300. A web 302 is rolled on a bobbin 304 from which the web 302 is fed to finish the packages. The slack 306 can be achieved by letting the web move along a wave- formed path where the sizes of the waves are adaptable to give a variable slack. Thus, during the reading operation, the speed can be controllable at the writing position 300, and the web 302 can be accelerated or decelerated between the reading operations to adapt to the average speed of the web. Here, the acceleration and deceleration is of course not made only to read a magnetic field mark; the reading is normally associated to an operation 308 for finishing the packages, e.g. for the cutting of the web 302 into parts 310 and transporting 312 them to forming operations (not shown), as demonstrated above.
At least one of the magnetic field marks for each package to be formed can be positioned not more than 20 %, preferably between 5 and 15 % of the width of the material to form a package from a longitudinal edge of the material to form the package. A magnetic field mark at such spots can then be used for controlling twisting of the material when forming the package. The forming of the package is normally made by forming some kind of tube which then is sealed in some way at its ends and formed into the desired shape, as demonstrated above. The tube can then be unintentionally twisted, which can jeopardize the forming of the package. Therefore, such a magnetic field mark can help to control any twisting of the tube to ensure forming of the package. By having these magnetic marks relatively close to the longitudinal edges to be joined to form the tube, the control is further enhanced since the reading of the magnetic field marks can be made from the side of the package where the joining takes place.
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