EP4782194A1

EP4782194A1 - Method for obtaining a plurality of multi-layer objects

Info

Publication number: EP4782194A1
Application number: EP25205561.1A
Authority: EP
Inventors: Paolo Carlo MONDINI; Daniel Paderni; Giorgia FRANCINI
Original assignee: G Mondini SpA
Current assignee: G Mondini SpA
Priority date: 2025-01-24
Filing date: 2025-09-30
Publication date: 2026-07-29

Abstract

A method for obtaining a plurality of multi-layer objects (1) comprising an initial step, in which a plurality of semi-finished elements (7) separate from each other are positioned next to each other, a coating step, in which a coating sheet (13) is fixed to the plurality of semi-finished elements (7) and a semi-finished product (15) is obtained comprising a plurality of coated elements (17) and a connecting portion (19), and a cutting step. Each coated element comprises a respective semi-finished element (7) and a respective second portion of the coating sheet comprising a central part (21), which together with a central portion (9) of the respective semi-finished element constitutes a main portion (25) corresponding to one of the multi-layer objects, and an annular part (23) which together with an annular portion (11) of the respective semi-finished element constitutes a secondary portion (27). In the cutting step, each main portion is separated from the respective secondary portion.

Description

This invention relates to a method for obtaining a plurality of multi-layer objects.
This invention relates to the making of multi-layer objects of the type comprising a basic support and a liner fixed on one side of that basic support, more specifically the making of multi-layer objects which are containers or, more generically, parts of packages usable in the packaging sector (for example lids, caps, parts of containers, etc.); despite that, it may also be used for making multi-layer objects of a different type whose production has similar requirements which can be met thanks to this invention.
Amongst the prior art methods for making multi-layer objects of the type indicated, there are some which involve obtaining each multi-layer object by deforming a respective sheet of multi-layer material comprising a layer which will define the basic support and a layer which will define the liner: however, such methods are difficult to implement or cannot be implemented at all where one of the layers of the multi-layer sheet (typically the layer intended to define the basic support) has limited deformability, and/or where the structure of the multi-layer object to be obtained is difficult to make by deformation of the multi-layer sheet (consider for example the making of a cylindrical container starting from a flat multi-layer sheet).
In a different way, some prior art methods involve, for each multi-layer object, making the basic support (already preformed according to the final shape required in the multi-layer object) and then applying its respective liner on it. In some prior art solutions the basic support is constituted of one or more sheets of folded material (for example paperboard); in other prior art solutions the basic support is constituted of moulded cellulose pulp. However, application of the liner does not allow the making of containers with a suitable level of finish, especially at their perimetric edge. When a liner is applied on the basic support, it is in fact practically impossible to perfectly superpose the two layers at the perimetric edge: one of the two normally projects outwards relative to the other.
Therefore, the prior art has several disadvantages, and the technical purpose which forms the basis of this invention is to at least partly overcome them.
In particular, the technical purpose of this invention is to obtain a method which allows the easy obtainment of a plurality of multi-layer objects having a suitable finish at the respective perimetric edges.
The technical purpose is substantially achieved by a method in accordance with what is defined in independent claims 1.
Particular embodiments of this invention are defined in the corresponding dependent claims.
Further characteristics and the advantages of this invention will be more apparent from the detailed description of several preferred, non-limiting embodiments, of a method for obtaining a plurality of multi-layer objects. Reference will be made to the schematic designs of the accompanying drawings, in which:

Figures 1A and 1B show, respectively in an axonometric view and in a top view, two multi-layer objects obtainable by means of the method according to this invention;
Figure 2 shows, in a front cross-section, the two multi-layer objects of Figure 1A;
Figure 3 is an enlarged view of the detail III of Figure 2;
Figures 4A and 4B show, respectively in a front view and in a top view, two semi-finished elements usable for making the multi-layer objects of Figure 1A in an initial step of the method;
Figure 5 shows, in a front view, the two semi-finished elements of Figure 4A and a coating sheet during a coating step;
Figures 6A and 6B show, respectively in a front view and in a top view, a semi-finished product obtained at the end of the coating step of Figure 5;
Figures 7A and 7B show, respectively in a front view and in a top view, the semi-finished product of Figure 6A at the start of a centring step;
Figures 8A and 8B show, respectively in a front view and in a top view, the semi-finished product of Figure 7A at the end of the centring step;
Figure 9 is an enlarged view of the detail IX of Figure 8A;
Figures 10A and 10B show, respectively in a front view and in a top view, the two multi-layer objects of Figure 1A and a piece of scrap obtained from the semi-finished product of Figure 8A at the end of a cutting step;
Figure 11 shows, in an axonometric view, a plurality of semi-finished elements during the initial step;
Figure 12 shows, in an axonometric view, a semi-finished product obtained starting from the plurality of semi-finished elements of Figure 11 at the end of the coating step;
Figure 13 shows, in an axonometric view, a plurality of multi-layer objects and a piece of scrap obtained from the semi-finished product of Figure 12 at the end of the cutting step;
Figures 14A and 14B show, respectively in a front view and in a top view, two rough objects obtained from the semi-finished product of Figure 6A at the end of a pre-cutting step in accordance with a way of implementing the method different from that illustrated in Figures 7A to 10B;
Figures 15A and 15B show, respectively in a front view and in a top view, the two rough objects of Figure 14A at the end of a positioning step;
Figures 16A and 16B show, respectively in a front view and in a top view, the two rough objects of Figure 15A at the start of the centring step;
Figures 17A and 17B show, respectively in a front view and in a top view, the two rough objects of Figure 16A at the end of the centring step;
Figures 18A and 18B show, respectively in a front view and in a top view, the two multi-layer objects of Figure 1A and two pieces of scrap obtained at the end of the cutting step.

As already indicated, the method in accordance with this invention is a method for obtaining a plurality of multi-layer objects 1, separate from each other, each comprising a basic support 3 and a liner 5 which is fixed on one side of the basic support 3; each multi-layer object 1 obtainable by means of this method comprises at least two superposed layers, one of which is defined by the basic support 3 and one defined by the liner 5. The layer defined by the basic support 3 may in turn comprise one or more layers, such as for example a layer of cellulose material (cellulose pulp, paperboard, etc.), and/or a layer of polymeric material, and/or a layer of metal material (aluminium); the layer defined by the liner 5 may in turn comprise one or more layers, such as for example one or more layers of polymeric material, and/or one or more layers of cellulose material, and/or a layer of aluminium. In some embodiments, the multi-layer objects 1 to be obtained are containers, and/or parts of containers, and/or parts of packages. Figures 1A to 3 illustrate two possible multi-layer objects 1 obtainable by means of this method.
In some embodiments, one or more multi-layer objects 1 to be obtained substantially extend two-dimensionally (they are substantially flat).
In some embodiments, each multi-layer object 1 to be obtained delimits a through hole (for example, has the shape of an annulus, or is substantially shaped like the lateral surface of a cylinder, or of a truncated cone, or of a truncated pyramid).
In general, the method according to this invention comprises first of all an initial step, during which a plurality of semi-finished elements 7 separate from each other (separate in the sense of elements which are apart, disconnected from each other) are positioned next to each other, one for each multi-layer object 1 to be obtained (consider the two embodiments illustrated in Figure 4B and in Figure 11). Each of those semi-finished elements 7 comprises a central portion 9, which corresponds to the basic support 3 of one of the multi-layer objects 1 to be obtained, and an annular portion 11 which surrounds the central portion 9. Although referred to with the term "annular", the annular portion 11 does not necessarily (substantially) have a circular shape: it surrounds the central portion 9 the way a ring surrounds a finger, but its precise structure depends on the structure of the central portion 9 which it surrounds; the annular portion 11 is a portion of the semi-finished element 7 which projects from the central portion 9 like an extension of the central portion 9. In Figures 4B and 11, for each semi-finished element 7 illustrated, the annular portion 11 and the central portion 9 are illustrated separated by a broken line, corresponding to the (future) outer edge of the basic support 3 of the desired multi-layer object 1. Each semi-finished element 7 is constituted of the material which in the final multi-layer object 1 constitutes the basic support 3.
Preferably, in the initial step the semi-finished elements 7 are positioned next to each other spaced apart in such a way that they are not in contact with each other. In other embodiments, in a different way, the semi-finished elements 7 are positioned laterally in contact with each other.
After the initial step, the method according to this invention comprises in general a coating step, during which a coating sheet 13 is fixed to the plurality of semi-finished elements 7 and a semi-finished product 15 is obtained comprising the plurality of semi-finished elements 7 and the coating sheet 13 fixed to them. The coating sheet 13 is flexible and is constituted of the material which in the final multi-layer object 1 constitutes the liner 5.
That semi-finished product 15 comprises a plurality of coated elements 17, their number equal to that of the plurality of semi-finished elements 7, and a connecting portion 19 which surrounds each coated element 17 and which connects the plurality of coated elements 17 to each other: the connecting portion 19 is defined by a first portion of the coating sheet 13, whilst each coated element 17 comprises a respective semi-finished element 7 and a respective second portion of the coating sheet 13 which is fixed to the respective semi-finished element 7 (the coating sheet 13 comprises as many second portions as there are coated elements 17).
For each coated element 17, the respective second portion of the coating sheet 13 comprises a central part 21, which is fixed to the central portion 9 of the respective semi-finished element 7, and an annular part 23 which is fixed to the annular portion 11 of the respective semi-finished element 7. The central part 21 (of the second portion of the coating sheet 13), together with a central portion 9 (of the semi-finished element 7), constitutes a main portion 25 of the coated element 17; that main portion 25 corresponds to one of the multi-layer objects 1 to be obtained. The annular part 23 (of the second portion of the coating sheet 13), together with the annular portion 11 (of the semi-finished element 7), constitutes a secondary portion 27 of the coated element 17 which surrounds the main portion 25 (which will subsequently be discarded as described in more detail below).
In the accompanying figures, for each coated element 17, the main portion 25 and the secondary portion 27 are illustrated divided by a broken line, corresponding to the (future) outer edge of the desired multi-layer object 1. In some embodiments, the coating step is a thermoforming step, in which the coating sheet 13 is thermoformed on the plurality of semi-finished elements 7: in such embodiments, a sheet of thermoformable material (such as an appropriate polymeric material) is used as the coating sheet 13. In accordance with one of those embodiments, Figure 5 shows a sheet of thermoformable material before being thermoformed and fixed to the semi-finished elements 7.
In some embodiments, during the coating step, the coating sheet 13 is glued or heat-sealed to the plurality of semi-finished elements 7.
Figures 6A and 6B illustrate a semi-finished product 15 obtained at the end of the coating step starting from the semi-finished elements 7 of Figures 4A and 4B; similarly, Figure 12 illustrates a semi-finished product 15 obtained at the end of the coating step starting from the semi-finished elements 7 of Figure 11 (a broken line illustrates the lower outlines of the semi-finished elements 7 hidden by the coating sheet 13).
In some embodiments, the coating step may be carried out twice on two opposite sides of the semi-finished elements 7.
After the coating step, the method according to this invention comprises in general a cutting step, during which the plurality of coated elements 17 is cut and each main portion 25 is separated from the respective secondary portion 27 (for each coated element 17, any continuity of the material between the main portion 25 and the secondary portion 27 is interrupted), obtaining the plurality of multi-layer objects 1 separate from each other. With reference to the accompanying figures, consider for example Figures 10A and 10B, which illustrate two multi-layer objects 1 (and a remaining piece of scrap) obtained from the semi-finished product 15 of Figure 8A and 8B, or Figure 13, which illustrates a plurality of multi-layer objects 1 (and a remaining piece of scrap) obtained from the semi-finished product 15 of Figure 12.
In some embodiments, for each coated element 17, the respective second portion of the coating sheet 13 also comprises a circumscribed part which is surrounded by the central part 21 (and which is in excess relative to what is necessary to make the liner 5 of the corresponding multi-layer object 1, for example because the multi-layer object 1 to be obtained delimits a through hole). In those embodiments, a cutting operation is carried out in which each circumscribed part is separated from the respective central part 21 (interrupting any continuity of material between the circumscribed part and the central part 21). Advantageously, that cutting operation is carried out during the cutting step (while each main portion 25 is separated from the respective secondary portion 27). However, it is possible for such a cutting operation to be carried out during an additional cutting step, distinct from the cutting step: in some embodiments, that additional cutting step is carried out after the cutting step; in other embodiments, that additional cutting step is carried out after the coating step and before the cutting step. Depending on the embodiments, the cutting operation may only affect the coating sheet 13 (if the semi-finished element 7 is pierced at the circumscribed part), or may also affect the semi-finished element 7. In the latter case, each semi-finished element 7 also comprises a circumscribed portion which is surrounded by the central portion 9 (and which is in excess of what is necessary to make the basic support 3 of the corresponding multi-layer object 1, for example because the multi-layer object 1 to be obtained delimits a through hole): for each coated element 17, the circumscribed part of the respective second portion of the coating sheet 13 is fixed to that circumscribed portion of the semi-finished element 7 and constitutes, with the circumscribed portion of the semi-finished element 7, a tertiary portion of the coated element 17 (in excess of what is necessary to make the corresponding multi-layer object 1) which is surrounded by the main portion 25. During the cutting operation (in which each circumscribed part is separated from the respective central part 21) each tertiary portion is separated from the respective central main portion 25 (interrupting any continuity of material between the tertiary portion and the main portion 25). In some cases, the circumscribed portion of the semi-finished element 7 may itself be pierced and be fixed to the circumscribed part only at a peripheral zone of the circumscribed part of the coating sheet 13.
In some embodiments, the cutting step is a mechanical cutting step, preferably a blanking step; in other embodiments, the cutting step is another type of mechanical cutting step, such as for example a die cutting step.
In some embodiments, the cutting step is in contrast a laser cutting step.
In some embodiments, during the cutting step, the coated elements 17 are cut and each main portion 25 is separated from the respective secondary portion 27 sequentially (one coated element 17 after another); in other embodiments, the coated elements 17 are cut and each main portion 25 is separated from the respective secondary portion 27 in groups of coated elements 17 (one group of coated elements 17 at a time); in other embodiments, in the preferred way, all of the coated elements 17 are cut simultaneously and all of the main portions 25 are simultaneously separated from the respective secondary portions 27.
In some embodiments of the invention, during the cutting step, the plurality of coated elements 17 is cut and each main portion 25 is separated from the respective secondary portion 27 using a cutting apparatus comprising a plurality of cutting devices - one for each multi-layer object 1 to be obtained - operating in parallel and positioned according to a predefined arrangement, in which each cutting device defines a respective reference axis 29 (an imaginary straight line) which is parallel to the reference axes 29 of the other cutting devices (advantageously, the reference axis 29 of each cutting device is an axis around which a closed cutting line is defined along which the cutting device is configured to cut). Advantageously, the reference axes 29 are vertical and the closed cutting lines lie in a horizontal plane.
Advantageously, the cutting step is a blanking step and the cutting apparatus used is a blanking machine, comprising a die and a plurality of punches (one for each multi-layer object 1 to be obtained), each insertable, in the known way, along a respective reference axis 29 into a respective cavity of the die (each punch - cavity pair being part of a respective cutting device).
In other embodiments, a cutting apparatus is used in which each cutting device comprises one or more blades.
In other embodiments, a cutting apparatus is used in which each cutting device is a laser cutting device.
In some embodiments, the method comprises a feeding step - carried out after the coating step and before the cutting step - in which the semi-finished product 15 is positioned at the cutting apparatus.
In other embodiments, at the cutting apparatus - in addition to the cutting step - the coating step is also carried out, the semi-finished product 15 obtained in the coating step in that way already being at the cutting apparatus. In some embodiments, the initial step is also carried out at the cutting apparatus.
Some embodiments of the method comprise a centring step carried out after the coating step and before the cutting step. In some embodiments comprising the feeding step, the centring step is carried out after the feeding step, that is to say, after having placed the semi-finished product 15 at the cutting apparatus, or during the feeding step (while positioning the semi-finished product 15 at the cutting apparatus).
During the centring step, the main portion 25 of each coated element 17 is centred relative to the reference axis 29 of a corresponding cutting device of the plurality of cutting devices (compare for example Figures 7A and 7B with Figures 8A and 8B). After the centring step, during the cutting step, the main portion 25 of each coated element 17 is kept centred relative to the reference axis 29 of the corresponding cutting device (of the plurality of cutting devices), so as to be able to correctly cut each coated element 17 and to obtain the desired multi-layer objects 1 (compare for example Figures 8A and 8B with Figures 10A and 10B).
In some embodiments, as described in more detail below, the centring step is carried out with the semi-finished product 15 whole (for example this is the case illustrated in Figures 7A, 7B, 8A and 8B); in other embodiments, as described in more detail below, the centring step is carried out after having divided the semi-finished product 15 into separate parts (for example this is the case illustrated in Figures 16A, 16B, 17A and 17B).
The main portion 25 of each coated element 17 advantageously defines its own (imaginary) main axis 31 - that is to say, an axis of the multi-layer object 1 to be obtained from that coated element 17 - which coincides with a central axis defined by the central portion 9 of the respective semi-finished element 7, and advantageously defines a main plane of extension which is perpendicular to the main axis 31. In some embodiments, the main axis 31 of each main portion 25 is for example an axis passing through the geometric centre of the main portion 25; in some embodiments, the main axis 31 is an axis defined by the intersection of two (or more) planes of symmetry of the main portion 25; in some embodiments, the main axis 31 is an axis of symmetry of the main portion 25 (such as for example in the embodiments illustrated). During the centring step, advantageously the main axis 31 of each main portion 25 (and, similarly, the central axis of each central portion 9) is made to coincide with the reference axis 29 of the corresponding cutting device (Figures 8A, 8B, 17A and 17B).
In some embodiments, during the centring step, at least two coated elements 17 (of the plurality of coated elements 17) are moved towards or away from each other and the connecting portion 19 of the semi-finished product 15 is deformed; preferably, only the connecting portion 19 of the semi-finished product 15 is deformed (the coated elements 17 are kept substantially undeformed). Preferably, the connecting portion 19 is deformed as a consequence of two or more of the coated elements 17 moving towards each other and/or of two or more of the coated elements 17 moving away from each other.
In some embodiments, two (or more) coated elements 17 are moved away from each other and, in a zone interposed between the two coated elements 17, the connecting portion 19 is subjected to traction and lengthens; advantageously, a sheet of plastically deformable material (advantageously made of a polymeric material) is used as the coating sheet 13 and, advantageously, the connecting portion 19 is plastically deformed.
In some embodiments, two (or more) coated elements 17 are moved towards each other and the connecting portion 19 which connects them bends (in some cases, for example, similarly to how a sheet of paper bends when two of its edges are moved towards each other). One of those embodiments is that illustrated in Figures 7A, 7B, 8A, 8B and 9. In those example figures, before carrying out the centring step (Figures 7A and 7B), the main portion 25 of the coated element 17 on the left is (already) centred relative to the reference axis 29 of the cutting device, and the main portion 25 of the coated element 17 on the right is off-centre relative to the reference axis 29 (in the top view, the main axis 31 of the main portion 25 is shifted to the right relative to the reference axis 29); at the end of the centring step (Figures 8A, 8B and 9), the main portion 25 of the coated element 17 on the right is translated to the left and, at a zone interposed between the two coated elements 17, the connecting portion 19 is deformed, bent in such a way as to form a bend 33 (a curve).
The specific way in which the connecting portion 19 deforms depends on the specific shape of the semi-finished product 15, on the mechanical properties of the semi-finished product 15, as well as on the specific change in the positions of the coated elements 17 relative to each other which takes place during the centring step, and can be determined by the technician in the sector in ways which are known and will not be discussed below.
In some embodiments, during the coating step (preferably after having fixed the coating sheet 13 to the plurality of semi-finished elements 7), one or more cuts are made at the connecting portion 19 while at the same time keeping the coated elements 17 connected to each other by means of the connecting portion 19, so as to facilitate the subsequent deformation of the connecting portion 19 of the semi-finished product 15 during the centring step.
In some embodiments, during the initial step, the semi-finished elements 7 of the plurality of semi-finished elements 7 are positioned according to an initial arrangement (relative to each other) which is determined based on the predefined arrangement of the plurality of cutting devices and, during the coating step, the semi-finished elements 7 are kept in that initial arrangement relative to each other (making sure that at the end of the coating step the semi-finished elements 7 are positioned according to the initial arrangement relative to each other). That initial arrangement refers to how the coated elements 17 are positioned relative to each other (that is to say, to the mutual positions of the coated elements 17) and is determined based on how the cutting devices of the plurality of cutting devices are positioned relative to each other (that is to say, based on the predefined arrangement of the cutting devices): for example, in the cases in which the predefined arrangement of the cutting devices is a grid arrangement, according to which the cutting devices are positioned in rows and columns, the semi-finished elements 7 are positioned according to an initial arrangement which - similarly - is a grid and has the same number of rows and the same number of columns as the predefined arrangement, plus advantageously the same distance between the rows and the columns.
In some embodiments, the semi-finished elements 7 are positioned according to the initial arrangement by inserting the semi-finished elements 7 into a plurality of cavities delimited by a supporting member and pre-shaped in such a way as to mate with respective surfaces of the semi-finished elements 7. In some embodiments, in which the coating step is a thermoforming step, that supporting member advantageously corresponds to a lower mould of a thermoforming machine.
In some embodiments comprising the centring step, at the start of the centring step the coated elements 17 are positioned in such a way that the respective semi-finished elements 7 are positioned according to the initial arrangement and then, during the carrying out of the centring step, the coated elements 17 are shifted relative to each other by moving two or more coated elements 17 towards and/or away from each other. Preferably, the initial arrangement is determined in such a way as to minimise relative movements of the coated elements 17 towards and/or away from each other during the centring step. In some embodiments, the initial arrangement, according to which the semi-finished elements 7 (of the plurality of semi-finished elements 7) are positioned during the initial step, requires respective orthogonal projections of the plurality of semi-finished elements 7 in a reference plane (an imaginary plane) to be separated from each other by a first safety distance 2, where each first safety distance 2 between two orthogonal projections of two adjacent semi-finished elements 7 is greater than or equal to a first predefined minimum distance (the semi-finished elements 7 do not overlap nor do they directly touch each other). In some embodiments, the first predefined minimum distance is equal to one millimetre, or greater than one millimetre; in other embodiments, the first minimum distance is less than one millimetre (in any case greater than zero millimetres). During the centring step, keeping the reference plane perpendicular to the reference axes 29 of the cutting devices (or, keeping the main axes 31 parallel to the reference axes 29), the main portion 25 of each of the plurality of coated elements 17 is centred relative to the reference axis 29 of the corresponding cutting device by translating, starting from the initial arrangement, at least one of the coated elements 17 by a respective first correction distance 4 parallel to the reference plane and keeping, in the reference plane, the respective orthogonal projections of the plurality of semi-finished elements 7 separate from each other.
Advantageously, that is achievable by calculating the first predefined minimum distance based on the maximum first correction distance 4 possible in the centring step. In some embodiments, the first predefined minimum distance is greater than double the component of the maximum first correction distance 4 measured along the same line along which the distance between two adjacent semi-finished elements 7 is measured (for example along the rows or the columns formed by the semi-finished elements 7), so that, in the centring step, the respective orthogonal projections are kept separate from each other by making sure that each component of the first correction distance 4 is less than half of the first predefined minimum distance. Advantageously, the maximum first correction distance 4 possible in the centring step is selected by taking into account the maximum imprecision that can be encountered in the arrangement of the semi-finished elements 7 in the semi-finished product 15.
Advantageously, in the initial step the semi-finished elements 7 are positioned according to an initial arrangement in such a way as to prevent, during the centring and cutting steps, the semi-finished elements 7 or the coated elements 17 from touching, or overlapping each other or the connecting portion 19.
In some embodiments of the method it is however possible that, during the cutting step and - where required - during at least part of the centring step, the semi-finished elements 7 touch each other.
In the case of the embodiment illustrated in Figures 7A, 7B, 8A and 8B: in the front views, the reference axes 29 lie in the plane of the sheet and are vertical, whilst the reference plane is horizontal and perpendicular to the sheet; in the top views (that is to say, in the plan views) the reference plane is parallel to the plane of the sheet, the reference axes 29 are perpendicular to the sheet and the top (plan) view of each coated element 17 substantially corresponds to the orthogonal projection of its respective semi-finished element 7 in the reference plane.
In some embodiments, in a different way, the coated elements 17 are kept positioned in such a way that the respective semi-finished elements 7 are positioned according to the initial arrangement relative to each other even during the cutting step: in those cases, the initial arrangement of the semi-finished elements 7 is determined by making sure that, with the semi-finished product 15 at the cutting apparatus, each main portion 25 is already centred relative to the reference axis 29 of a corresponding cutting device; advantageously, the initial arrangement is determined in such a way that the centre to centre distances between the central axes of the central portions 9 - and therefore between the main axes 31 of the main portions 25 - correspond to the centre to centre distances which separate the reference axes 29 of the cutting devices.
In some embodiments in which the initial step and the coating step are carried out at the cutting apparatus (without the need for any feeding step as described above), the semi-finished elements 7 are positioned already centred relative to the reference axes 29 during the initial step (advantageously, with the central axes coincident with the reference axes 29), and the coating step and the cutting step are carried out while keeping their positions relative to each other unchanged (with no need for any centring step as described above).
In some embodiments comprising the feeding step (in which the initial step and the coating step are carried out outside of the cutting apparatus), the centring step is carried out while keeping the semi-finished elements 7 in the initial arrangement, that is to say, all of the main portions 25 are simultaneously centred relative to the reference axes 29 of the cutting devices without changing their positions relative to each other (advantageously, by moving the semi-finished product 15 in a substantially rigid way). In some embodiments, the feeding step and the centring step are carried out simultaneously, that is to say, the semi-finished product 15 is positioned at the cutting apparatus in such a way that its main portions 25 are centred relative to the reference axes 29. In other embodiments, the centring step is carried out after the feeding step: in the feeding step, the semi-finished product 15 is positioned at the cutting apparatus with the main portions 25 which may be off-centre relative to the reference axes 29 of the cutting devices and, in the centring step, if necessary, the semi-finished product 15 is moved, thereby centring the main portions 25 relative to the reference axes 29.
Unlike in the embodiments above in which the centring step is carried out with the semi-finished product 15 whole, some embodiments of the method comprise a pre-cutting step (a preliminary cutting step), carried out after the coating step and before the centring step, and, in some embodiments, a positioning step carried out after the pre-cutting step and before the centring step.
During the pre-cutting step, the semi-finished product 15 is cut at the connecting portion 19 separating each coated element 17 from the other coated elements 17 (interrupting any continuity of material between one coated element 17 and another) and a plurality of rough objects 35 separate from each other is obtained, one for each multi-layer object 1 to be obtained (Figures 14A and 14B illustrate two rough objects 35 obtained at the end of such a pre-cutting step). Each rough object 35 obtained in the pre-cutting step is constituted of one of the coated elements 17 and of a projecting border 37 which surrounds the coated element 17 and which corresponds to part of the connecting portion 19; each rough object 35 is therefore "rough" in the sense of an object in its preliminary stages from which, by means of suitable finishing-off (removal of the projecting border 37 and of the secondary portion 27), a respective multi-layer object 1, that is to say, the "finished" object, is obtainable.
During the positioning step, the rough objects 35 are positioned according to a spaced apart arrangement in which they are spaced apart from each other (Figures 15A and 15B show the two rough objects 35 of Figures 14A and 14B at the end of the positioning step). The positioning step is carried out with reference to respective orthogonal projections of the plurality of rough objects 35 in a reference plane (understood to be an infinite ideal plane); when the rough objects 35 are in the spaced apart arrangement, those orthogonal projections are - in the reference plane - separated from each other by a second safety distance 6, and each second safety distance 6 between two orthogonal projections of two adjacent rough objects 35 is greater than a second predefined minimum safety distance, or equal to a second predefined minimum distance. In some embodiments, the second predefined minimum distance is equal to one millimetre, or greater than one millimetre; in other embodiments, the second minimum distance is less than one millimetre (in any case greater than zero millimetres). The positioning step is carried out in such a way that, at least at the end of it, all of the rough objects 35 are positioned with the main plane of extension of the relative main portion 25 parallel to the reference plane (that is to say, with the main axes 31 perpendicular to the reference plane). In the case of the embodiment illustrated in Figures 14A to 17B: in the front views, the reference axes 29 lie in the plane of the sheet and are vertical, whilst the reference plane is horizontal and perpendicular to the sheet; in the top views (that is to say, in the plan views) the reference plane is parallel to the plane of the sheet, the reference axes 29 are perpendicular to the sheet and the top (plan) view of each rough object 35 corresponds to its orthogonal projection in the reference plane.
Before carrying out the positioning step, the rough objects 35 are positioned according to a near arrangement, according to which each orthogonal projection in the reference plane is separated from another adjacent orthogonal projection by a distance which is less than the second predefined minimum distance. In many embodiments, the near arrangement is that in which the rough objects 35 are found at the end of the pre-cutting step and the distance between the rough objects 35 corresponds to the distance which separates them at the end of the pre-cutting step (advantageously corresponding only to the thickness of the cut). In the positioning step, the rough objects 35 are then moved from the near arrangement to the spaced apart arrangement. Advantageously, at least if the multi-layer objects 1 to be obtained are all equal to each other, at least at the end of the positioning step the rough objects 35 are positioned with the main planes of extension of the relative main portions 25 coplanar with each other. In the positioning step the rough objects 35 are spaced apart so as to prevent, during the subsequent centring and cutting steps, them from touching or overlapping each other (which would be possible if they remained in the near arrangement).
In some embodiments of the method, in a different way, the positioning step is not included and it is possible that, during at least part of the centring step and during the cutting step, the rough objects 35 touch each other.
During the centring step, the main portion 25 of each rough object 35 is centred relative to the reference axis 29 of the respective cutting device, advantageously keeping the reference plane perpendicular to the reference axes 29 of the cutting devices, (compare Figures 16A and 16B with Figures 17A and 17B). Advantageously, in the centring step, the main portions 25 are centred by translating, starting from the spaced apart arrangement, at least one of the rough objects 35 by a respective second correction distance 8 parallel to the reference plane and also keeping, in the reference plane, the respective orthogonal projections of the plurality of rough objects 35 separate from each other (in that step, the rough objects 35 neither touch nor overlap each other).
The positioning step, carried out before the centring step, is carried out in such a way as to separate the rough objects 35 from each other enough to prevent them from making contact or overlapping each other during the centring step. That guarantees correct centring of every single main portion 25 relative to the reference axis 29 of the cutting device without interference between adjacent rough objects 35.
Advantageously, that is achievable by calculating the second predefined minimum distance - taken as a reference in the positioning step - based on the maximum second correction distance 8 possible in the centring step. In some embodiments, the second predefined minimum distance is greater than double the component of the maximum second correction distance 8 measured along the same line along which the distance between two adjacent rough objects 35 is measured (for example along the rows or the columns formed by the rough objects 35), so that, in the centring step, the respective orthogonal projections are kept separate from each other by making sure that each component of the second correction distance 8 is less than half of the second predefined minimum distance. Advantageously, the maximum second correction distance 8 possible in the centring step is selected by taking into account the maximum imprecision that can be encountered in the arrangement of the semi-finished elements 7 in the semi-finished product 15.
The second correction distance 8 is understood to be a component, parallel to the reference plane, of the overall shifting to which the rough object 35 is subjected in the centring step (overall shifting understood to be the difference between the initial position and the final position): in some embodiments, a rough object 35 is translated parallel to the reference plane and the overall shifting is parallel to the reference plane; in some embodiments, at least one of the rough objects 35 is translated - not just by a second correction distance 8 parallel to the reference plane - but also by a distance perpendicular to the reference plane (moving the rough object 35 away from the reference plane). In some embodiments, instead of cutting the connecting portion 19 of the semi-finished product 15 in such a way as to separate each coated element 17 from the others (so as to cut out the plurality of rough objects 35 from the semi-finished product 15), the semi-finished product 15 is cut into two or more semi-finished sub-products separate from each other and each comprising a sub-group of the plurality of coated elements 17 and part of the connecting portion 19 (for example, the semi-finished product 15 is cut in half), and then each of the semi-finished sub-products is cut in one of the ways described above for the case of the whole single semi-finished product 15.
Advantageously, after having performed a first implementation of the method according to this invention and having obtained the multi-layer objects 1, it is possible to perform a second implementation of the method in which the plurality of multi-layer objects 1 - obtained in the first implementation of the method - are used as semi-finished elements 7 to obtain a plurality of different multi-layer objects. That is particularly useful if the desired different multi-layer objects each comprise a main layer and two coating layers which are fixed on two different sides of the main layer (which is constituted of part of the semi-finished element 7 used in the first implementation of the method), in particular which are fixed on two opposite sides (think for example of the case of containers with a cellulose main layer and two polymeric coating layers, one of which is fixed on the inner side intended to receive a product and the other of which is fixed on the outer side): with each implementation of the method, one of the two coating layers is applied to the main layer.
This invention has important advantages.
In fact, by means of this invention it was possible to obtain a method which allows easy obtainment of a plurality of multi-layer objects having suitable finish at the respective perimetric edges, at which neither the basic support nor the liner projects outwards relative to the other.
The invention described above may be modified and adapted in several ways without thereby departing from the scope of the inventive concept as defined in the independent claims.
All details may be substituted with other technically equivalent elements and the materials used, as well as the shapes and dimensions of the various components, may vary according to requirements.

Claims

Method for obtaining a plurality of multi-layer objects (1), separate from each other, each comprising a basic support (3) and a liner (5) fixed on one side of the basic support (3), the method comprising an initial step, a coating step and a cutting step, wherein:
during the initial step, a plurality of semi-finished elements (7) separate from each other are positioned next to each other, one for each multi-layer object (1) to be obtained, each semi-finished element (7) comprising a central portion (9), which corresponds to the basic support (3) of one of the multi-layer objects (1) to be obtained, and an annular portion (11) which surrounds the central portion (9);

during the coating step, a coating sheet (13) is fixed to the plurality of semi-finished elements (7) and a semi-finished product (15) is obtained, said semi-finished product (15) comprising a plurality of coated elements (17) and a connecting portion (19) which surrounds each coated element (17) and connects the plurality of coated elements (17) to each other, the connecting portion (19) being defined by a first portion of the coating sheet (13) and each coated element (17) comprising a respective semi-finished element (7) and a respective second portion of the coating sheet (13) fixed to the respective semi-finished element (7);

for each coated element (17), said respective second portion of the coating sheet (13) comprises a central part (21), which is fixed to the central portion (9) of the respective semi-finished element (7), and an annular part (23) which is fixed to the annular portion (11) of the respective semi-finished element (7);

said central part (21) together with the central portion (9) constitutes a main portion (25) of the coated element (17) which corresponds to one of the multi-layer objects (1) to be obtained;

said annular part (23) together with the annular portion (11) constitutes a secondary portion (27) of the coated element (17) which surrounds the main portion (25); and

during the cutting step, the plurality of coated elements (17) is cut and each main portion (25) is separated from the respective secondary portion (27).
The method according to claim 1, wherein during the cutting step the plurality of coated elements (17) is cut and each main portion (25) is separated from the respective secondary portion (27) using a cutting apparatus comprising a plurality of cutting devices operating in parallel and positioned according to a predefined arrangement, one for each multi-layer object (1) to be obtained, each cutting device defining a respective reference axis (29) which is parallel to the reference axes (29) of the other cutting devices.
The method according to claim 2, also comprising a feeding step, carried out after the coating step and before the cutting step, wherein the semi-finished product (15) is positioned at the cutting apparatus.
The method according to claim 2 or 3, also comprising a centring step carried out after the coating step and before the cutting step, wherein:
during the centring step, the main portion (25) of each coated element (17) is centred relative to the reference axis (29) of a corresponding cutting device of the plurality of cutting devices; and

during the cutting step, the main portion (25) of each coated element (17) is kept centred relative to the reference axis (29) of the corresponding cutting device of the plurality of cutting devices.
The method according to claim 4 when it depends on claim 3, wherein the centring step is carried out after the feeding step or during the feeding step.
The method according to any one of claims 2 to 5, wherein:
during the initial step, the semi-finished elements (7) of the plurality of semi-finished elements (7) are positioned according to an initial arrangement relative to each other, said initial arrangement being determined based on the predefined arrangement of the plurality of cutting devices; and

during the coating step, the semi-finished elements (7) are kept in the initial arrangement relative to each other.
The method according to claim 6, wherein, during the cutting step, the semi-finished elements (7) of the plurality of semi-finished elements (7) are kept positioned according to the initial arrangement relative to each other.
The method according to claim 4, or 5, or 6 when it depends on claim 4, wherein during the centring step at least two coated elements (17) of the plurality of coated elements (17) are moved towards or away from each other and the connecting portion (19) of the semi-finished product (15) is deformed.
The method according to claim 8 when it depends on claim 3, wherein:
during the initial step, the initial arrangement according to which the semi-finished elements (7) of the plurality of semi-finished elements (7) are positioned requires respective orthogonal projections of the plurality of semi-finished elements (7) in a reference plane to be separated from each other by a first safety distance (2), each first safety distance (2) between two orthogonal projections of two adjacent semi-finished elements (7) being greater than or equal to a first predefined minimum distance; and
during the centring step, keeping the reference plane perpendicular to the reference axes (29) of the cutting devices, the main portion (25) of each of the plurality of coated elements (17) is centred relative to the reference axis (29) of the corresponding cutting device by translating, starting from the initial arrangement, at least one of the coated elements (17) by a respective first correction distance (4) parallel to the reference plane and keeping, in the reference plane, the respective orthogonal projections of the plurality of semi-finished elements (7) separate from each other.
The method according to claim 6 when it depends on claim 4, also comprising a pre-cutting step, carried out after the coating step and before the centring step, and a positioning step, carried out after the pre-cutting step and before the centring step, wherein:
during the pre-cutting step, the semi-finished product (15) is cut at the connecting portion (19) separating each coated element (17) from the other coated elements (17) and a plurality of rough objects (35) separate from each other is obtained, one for each multi-layer object (1) to be obtained, each rough object (35) being constituted of one of the coated elements (17) and of a projecting border (37) which surrounds the coated element (17) and which corresponds to part of the connecting portion (19);

during the positioning step, the rough objects (35) are positioned according to a spaced apart arrangement, according to which respective orthogonal projections of the plurality of rough objects (35) in a reference plane are separated from each other by a second safety distance (6), each second safety distance (6) between two orthogonal projections of two adjacent rough objects (35) being greater than or equal to a second predefined minimum distance;

during the centring step, keeping the reference plane perpendicular to the reference axes (29) of the cutting devices, the main portion (25) of each of the plurality of rough objects (35) is centred relative to the reference axis (29) of the corresponding cutting device by translating, starting from the spaced apart arrangement, at least one of the rough objects (35) by a respective second correction distance (8) parallel to the reference plane and keeping, in the reference plane, the respective orthogonal projections of the plurality of rough objects (35) separate from each other.
The method according to any one of claims 1 to 10, wherein:
for each coated element (17), said respective second portion of the coating sheet (13) also comprises a circumscribed part which is surrounded by the central part (21); and

a cutting operation in which each circumscribed part is separated from the respective central part (21) is carried out.
The method according to claim 11, wherein:
each semi-finished element (7) also comprises a circumscribed portion which is surrounded by the central portion (9);

for each coated element (17), the circumscribed part of the respective second portion of the coating sheet (13) is fixed to said circumscribed portion of the semi-finished element (7) and constitutes, with said circumscribed portion of the semi-finished element (7), a tertiary portion of the coated element (17) which is surrounded by the main portion (25); and

in said cutting operation, each tertiary portion is separated from the respective main portion (25).
The method according to any one of claims 1 to 12, wherein the cutting step is a blanking step.
The method according to any one of claims 1 to 13, wherein the coating step is a thermoforming step in which the coating sheet (13) is thermoformed on the plurality of semi-finished elements (7).
The method according to any one of claims 1 to 14, wherein the multi-layer objects (1) to be obtained are containers, and/or parts of containers, and/or parts of packages.