Assembly and method for cutting a tie by means of a remote laser

Abstract

The invention relates a cutting assembly (10) for cutting at least one tie (6) surrounding a product (8), the cutting assembly (10) comprising: - a cutting unit (12), configured to emit laser beams (15) focused on the tie (6); - a control unit (14), configured to detect the presence of the tie (6) and the position of the tie (6) with respect to an optical system (18) of the cutting unit (12), and, based on the detected position of the tie (6), to order the cutting unit (12) to perform a series of at least two steps of cutting a continuous portion (20) of the tie (6) from a first transverse edge (61) to a second transverse edge (62) of the tie (6).

Description

[0001] Assembly and method for remote laser cutting of a ligature

[0002] The present invention relates to an assembly for cutting at least one ligature enclosing a product, as well as an associated cutting method.

[0003] The present invention applies to all products packaged with ligatures, in particular to coils, packages, batches and crowns. The present invention applies in particular to coils of flat metal products.

[0004] It is common for products to be packaged and held together by means of ties, for example in the form of reels, bundles, batches or crowns.

[0005] This is particularly the case for metal sheets and strips, especially steel, which are commonly presented in the form of coils or bundles (also called stacks), held together by one or more ties, also called ligatures. Said ligatures are, for example, made of plastic or metal and are used to keep the coils or bundles in shape, for example by strapping them. These ligatures are removed to allow the coils to be unwound or the bundles to be unpacked at the line entrance.

[0006] Ligature removal can be done manually by an operator. However, this operation is time-consuming and can present risks for the operator due to the elastic return of the ligature and / or the coil.

[0007] Mechanical devices for cutting ligatures are also known, in the form of a robot comprising a ligature detection system and a cutting tool in the form of shears suitable for cutting the ligatures.

[0008] However, such devices have drawbacks. The cutting tool is not suitable for thick or overlapping ligatures due to the size of the tool. Similarly, when a ligature loosely surrounds the coil, the cutting tool may have difficulty cutting it. The same is true if the ligature is too tight: the cutting tool cannot then pass between the ligature and the coil or bundle. In addition, such devices are expensive and require a heavy and bulky hydraulic arm. They do not allow for rapid removal of ligatures. Finally, there is also a risk of damage to the surface of the coils or bundles, such as scratches.

[0009] The aim of the invention is therefore to propose a cutting assembly allowing rapid and safe removal of the ligatures surrounding a product, while limiting the risks of damage to the product.

[0010] To this end, the invention relates to a cutting assembly for at least one ligature enclosing a product, for example a coil of a flat metal product, the ligature having a thickness of between 0.5 and 3 mm, the ligature extending, along a width between a first transverse edge and a second transverse edge, the cutting assembly comprising:

[0011] - a cutting unit configured to emit laser beams focused on the ligature, comprising a laser capable of emitting beams, an optical system configured to move and focus the beams received from the laser such that the focused beams impact a continuous portion of the ligature from the first transverse edge to the second transverse edge of the ligature,

[0012] - a control unit, configured to detect the presence of the ligature and the position of the ligature relative to the optical system, and, from the position of the ligature detected, to command the cutting unit to carry out a series of at least two cutting steps of the continuous portion of ligature, the control unit being configured to, at each cutting step: command the cutting unit to implement a cutting scan of the continuous portion of ligature, the scan comprising an emission of focused beams received on the continuous portion of ligature, from the first transverse edge to the second transverse edge of the ligature, each cutting scan ablating the continuous portion of ligature over a layer of thickness at most equal to 50% of the thickness of the ligature, detect the presence or absence of the ligature around the product following the implementation of the scan, and selectively,perform an additional cutting step if the presence of the ligature is detected, or interrupt the series of cutting steps if the absence of the ligature is detected.,

[0013] The cutting assembly according to the invention thus makes it possible to cut the ligature quickly, safely and precisely, by removing a layer of the ligature of limited thickness with each pass. The risks of damage to the product are therefore reduced.

[0014] According to other advantageous aspects of the invention, the cutting assembly comprises one or more of the following characteristics, taken individually or in all technically possible combinations:

[0015] - the optical system comprises a focusing device and a scanning device, the scanning device being configured to selectively deflect the beams emitted by the laser onto the focusing device, the focusing device being configured to focus the beams deflected by the scanning device into a focusing plane perpendicular to a normal to the ligature portion and intersecting the ligature portion; - a distance between the focusing device and the focusing plane is greater than or equal to the width of the ligature between the first lateral edge and the second lateral edge;

[0016] - the laser is capable of emitting pulsed beams, the optical system is configured to move and focus the pulsed beams received from the laser such that the focused pulsed beams impact the continuous portion of the ligature in a plurality of contiguous spots from the first transverse edge to the second transverse edge of the ligature;

[0017] - the laser is capable of emitting continuous beams, the optical system is configured to move and focus the beams received from the laser such that the focused beams impact the continuous portion of the ligature along a line extending from the first transverse edge to the second transverse edge of the ligature;

[0018] - the scanning device includes a galvanometric scanner or a polygonal scanner;

[0019] - the focusing device comprises at least one f-theta lens or flat field lens or a focusing mirror;

[0020] - the focusing device has a focal distance greater than or equal to the width of the ligature between the first transverse edge and the second transverse edge;

[0021] - the cutting unit further comprises a movement device configured to, before each cutting step, move the optical system relative to the product, in a direction orthogonal to the focusing plane, such that the focusing plane intersects the ligature portion, and / or parallel to the width of the ligature, the control unit being configured to control a movement of the optical system by the movement device as a function of the position of the detected ligature;

[0022] - during each scan, an energy density received at each position of the ligature portion is adapted to ablate a layer of the ligature with a thickness of at least 50 pm and at most equal to 50% of the thickness of the ligature, in particular between 50 pm and 200 pm;

[0023] - the product being surrounded by at least two ligatures, the control unit is configured to detect the number of ligatures, the presence and the position of each ligature relative to the optical system, and, from the position of each ligature detected, to command the cutting unit to carry out a series of at least two cutting steps of a continuous portion of each ligature, the control unit being configured to, at each cutting step:

[0024] * command the cutting unit to implement a cutting scan of the continuous portion of each ligature, the scan successively comprising, for each ligature detected, an emission of focused beams received on the continuous portion of the ligature detected from the first transverse edge to the second transverse edge of the ligature,

[0025] * detecting the presence or absence of each ligature around the product following the implementation of the scan, and selectively, performing an additional cutting step if the presence of at least one ligature is detected, or interrupting the series of cutting steps if the absence of ligatures is detected;

[0026] - the cutting assembly further comprises a protective enclosure capable of receiving at least part of the product during cutting;

[0027] - the cutting assembly further comprises a module for collecting the ligature after it has been cut, configured to grasp the cut ligature and convey the cut ligature away from the product, in particular to a storage container.

[0028] The invention also relates to a method of cutting, by a cutting assembly of the aforementioned type, at least one ligature enclosing a product, the ligature having a thickness of between 0.5 and 3 mm, the ligature extending, along a width, between a first transverse edge and a second transverse edge, the method comprising the detection, by the control unit, of the position of the ligature relative to the optical system, and, from the detected position, the performance of a series of at least two steps of cutting a continuous portion of the ligature from the first transverse edge to the second transverse edge of the ligature, each cutting step comprising:

[0029] - the control, by the control unit, of the implementation by the cutting unit of a cutting scan of the continuous portion of ligature,

[0030] - the implementation, by the cutting unit, of the cutting scan controlled by the control unit, comprising the emission of beams by the laser and the displacement and focusing by the optical system of the beams such that the focused beams, during the displacement, impact the continuous portion of ligature from the first transverse edge to the second transverse edge of the ligature, each cutting scan ablating the continuous portion of ligature over a thickness at most equal to 50% of the thickness of the ligature,

[0031] - the detection, by the detection unit, of the presence or absence of the ligature around the product following the implementation of the scan by the cutting unit, and

[0032] - selectively, carrying out an additional cutting step if the presence of the ligature is detected, or interrupting the series of cutting steps if the absence of the ligature is detected. According to other advantageous aspects of the invention, the method comprises one or more of the following features, taken individually or in all technically possible combinations:

[0033] - the optical system comprising a focusing device and a scanning device, the scanning device being configured to selectively deflect the beams emitted by the laser onto the focusing device, the focusing device being configured to focus the beams deflected by the scanning device in a focusing plane perpendicular to a normal to the ligature portion and intersecting the ligature portion, during each scan, the beams emitted by the laser are selectively deflected by the scanning device to be focused by the focusing device, such that the focused beams impact the ligature portion from the first transverse edge to the second transverse edge;

[0034] - a distance between the focusing device and the product is greater than or equal to the width of the ligature between the first transverse edge and the second transverse edge;

[0035] - the laser emits pulsed beams, the cutting scan comprises the emission of focused pulsed beams received in a plurality of contiguous spots on the continuous portion of ligature, from the first transverse edge to the second transverse edge of the ligature;

[0036] - the laser emits continuous beams, the cutting scan comprises emission of continuous beams by the laser and the displacement and focusing by the optical system of the beams such that the focused beams, during the displacement, impact the ligature portion along a line extending from the first transverse edge to the second transverse edge of the ligature;

[0037] - the cutting method comprises, before carrying out the series of cutting steps or before at least one cutting step, a relative movement of the optical system with respect to the product as a function of the position of the detected ligature, in a direction orthogonal to the focusing plane such that the focusing plane intersects the ligature portion and / or in a direction parallel to the width of the ligature;

[0038] - during each scan, an energy density received at each position of the ligature portion ablates a layer of the ligature with a thickness of at least 50 pm and at most equal to 50% of the thickness of the ligature, in particular between 50 pm and 200 pm;

[0039] - the product being surrounded by at least two ligatures, the method comprises the detection, by the control unit, of the number of ligatures and the position of each ligature relative to the optical system, and, from the position of each ligature detected, the carrying out of a series of at least two steps of cutting a continuous portion of each ligature, each cutting step comprising:

[0040] * the control, by the control unit, of the implementation by the cutting unit of a cutting scan of the continuous portion of each detected ligature,

[0041] * the implementation, by the cutting unit, of the cutting scan controlled by the control unit, comprising the emission of beams by the laser and the displacement and focusing by the optical system of the beams such that the focused beams, during the displacement, successively impact the continuous portions of the ligatures detected from the first transverse edge to the second transverse edge of each ligature,

[0042] * the detection, by the detection unit, of the presence or absence of each ligature around the product following the implementation of the scan by the cutting unit, and

[0043] * selectively performing an additional cutting step if the presence of at least one ligature is detected, or interrupting the series of cutting steps if the absence of ligatures is detected.

[0044] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0045] [Fig. 1] Figure 1 is a schematic representation of an assembly for cutting at least one ligature according to an embodiment of the present invention;

[0046] [Fig. 2] Figure 2 is a schematic representation of an optical system of the cutting assembly of Figure 1;

[0047] [Fig. 3] Figure 3 is an enlarged view of Figure 1 at a ligature as it is cut by the cutting assembly.

[0048] Figure 1 schematically shows a cutting assembly 10 according to the invention.

[0049] The cutting assembly 10 is intended to cut at least one tie 6 enclosing a packaged product 8.

[0050] In the remainder of the description, the product 8 is a flat metal product 8 in the form of a coil 7.

[0051] Alternatively, the product 8 is in the form of a stack or bundle, for example a stack or bundle of sheets, in the form of a crown, or in any other form held by means of at least one tie. In the embodiment of Figure 1, the flat metal product 8 is a metal strip or sheet wound on itself so as to form a coil 7 defining a central axis C of the coil 7, also called the winding axis. A transverse plane of the coil 7 is defined, said transverse plane being normal to the central axis C of the coil 7.

[0052] The product 8 is for example made of steel, for example stainless steel. Alternatively, the product 8 is made of non-metallic material, for example plastic, composite material or wood.

[0053] The flat metal product 8 is held in the form of a coil 7 by means of at least one tie 6 surrounding said coil 7.

[0054] The ligature 6 is made of a material suitable for holding the coil 7 in its wound form.

[0055] For example, the ligature 6 is made of plastic, preferably polypropylene (PP), polyester (PE) and / or polyethylene terephthalate (PET).

[0056] Alternatively, the ligature 6 is made of metal, preferably carbon steel, stainless steel, aluminum and / or alloys, for example Ni or Cu-based alloys.

[0057] When it does not enclose the coil 7, the ligature 6 extends in length between a first and a second longitudinal end (not shown), in width between a first transverse edge 61 and a second transverse edge 62, and in thickness between a first face 63, called the internal face, intended to be in contact with the coil 7 when the ligature 6 encloses said coil 7, and a second face 64, called the external face, opposite the first face 63.

[0058] For example, the ligature 6 has a width L of between 5 mm and 50 mm, measured between the first transverse edge 61 and the second transverse edge 62.

[0059] Typically, the ligature 6 has a thickness e of between 0.5 mm and 3.0 mm, measured between the first face 63 and the second face 64.

[0060] The ligature 6 is held around the coil 7 by attachment means known per se. For example, the ends of the ligature 6 are fixed to each other by welding, gluing or by means of a staple.

[0061] According to a first embodiment, shown in Figure 1, the ligature 6 surrounds the coil 7 circumferentially, around the central axis C of the coil 7. The ligature 6 therefore extends parallel to the transverse plane of the coil 7 and encircles said coil 7. In a variant (not shown), said ligature 6 surrounds a portion of the coil 7 by passing inside and outside said coil 7. Said ligature 6 then extends essentially in a direction parallel to the central axis C of the coil 7.

[0062] In the example of Figure 1, two ligatures 6 enclose the coil 7. Said ligatures 6 may be identical or be made of different materials and / or have different dimensions.

[0063] In the example of Figure 1, the two ligatures 6 extend substantially parallel to each other and surround the coil 7 around the central axis C of the coil 7.

[0064] Alternatively (not shown), the two ligatures 6 extend substantially perpendicular to each other, a first ligature 6 surrounding the coil 7 around the central axis C of the coil 7 and a second ligature 6 surrounding a portion of the coil 7 passing inside and outside said coil 7.

[0065] For example, between one and twenty-five ligatures 6 encircle(s) a coil 7. Said ligatures 6 may be identical or different and may be arranged in positions and arrangements which would be obvious to those skilled in the art.

[0066] According to the embodiment shown in FIG. 1, the cutting assembly 10 comprises a cutting unit 12 and a control unit 14.

[0067] The cutting unit 12 is configured to emit laser beams 15 focused on the ligature 6.

[0068] The cutting unit 12 comprises a laser 16 capable of emitting beams and an optical system 18 configured to move and focus the beams received from the laser 16 such that the focused beams impact a continuous portion 20 of the ligature 6 from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0069] By "continuous portion of the ligature" is meant here a segment of said ligature 6 extending between the first transverse edge 61 and the second transverse edge 62.

[0070] The laser 16 is capable of emitting pulsed beams and / or continuous beams.

[0071] Laser 16 is for example a fiber laser.

[0072] The laser 16 is preferably capable of emitting laser beams having radiation in a wavelength range between 200 nm (ultraviolet radiation) and 2000 nm (near infrared radiation), for an emitted power of between 50 W and 10 kW. For example, the laser 16 is a continuous or pulsed laser. For example, the laser 16 is a continuous laser emitting in the near infrared, typically at 1070 nm, for a power of 2 kW.

[0073] Preferably, the laser 16 further comprises an optical fiber 161 configured to transmit the radiation towards the optical system 18, which is advantageously located at a distance, typically more than 1 m.

[0074] The optical system 18 is configured to move and focus the beams received from the laser at an impact zone.

[0075] The optical system 18 includes a focusing device 22 and a scanning device 24 configured to selectively deflect the beams emitted by the laser 16 onto the focusing device 22.

[0076] The focusing device 22 is configured to focus the beams deflected by the scanning device 24 in a focusing plane P shown in FIG. 3, said focusing plane P being perpendicular to a normal to the portion 20 of ligature 6.

[0077] The focusing device 22 is configured to focus the beams deflected by the scanning device 24 in a focusing plane P perpendicular to a normal to the ligature portion 20, said plane P being tangent or intersecting said ligature portion 20 6.

[0078] Preferably, the focusing plane P intersects said portion 20 of ligature 6, so that the focusing plane P is not only tangent to the external face 64 of the ligature portion, but is located in the thickness of said portion.

[0079] Thus, the energy density received at the portion 20 of the ligature 6 is sufficient to allow the ablation of material.

[0080] Preferably, the beam 15 impacts the continuous portion 20 of the ligature 6 over an area of ​​between 10 pm and 100 pm.

[0081] Preferably, the focusing device 22 comprises at least one f-theta lens or flat field lens or a focusing mirror.

[0082] Advantageously, the focusing device 22 has a focal distance greater than or equal to the width L of the ligature 6.

[0083] Thus, the focusing device 22 is advantageously arranged at a distance d from the focusing plane P so that said distance d is greater than or equal to the width L of the ligature 6.

[0084] For example, the distance d is between 5 cm and 200 cm.

[0085] Said distance d allows cutting without being too close to the cut surface, as in the case of a conventional cutting head. This reduces the risks of breakage and projection onto the optical system. The scanning device 24 is configured to selectively deflect the beams emitted by the laser 16 onto the focusing device 22, so as to move the impact zone of the beams 15 focused onto the ligature 6.

[0086] Advantageously, the scanning device 24 is configured to, in response to a command to emit a beam focused at a given position on the portion 20 of the ligature 6, deflect a beam received from the laser 16 towards the focusing device 22 such that the beam 15 deflected and focused by the focusing device 22 impacts the ligature 6 at said given position. Said emission command is preferably received from the control unit 14, as will be described later.

[0087] Preferably, the scanning device 24 is configured to move the beams 15 focused in the focusing plane P in a first direction parallel to the width L of the ligature 6. The movement of the beams then takes place in the width of the ligature 6.

[0088] Advantageously, the scanning device 24 is also configured to move the beams 15 focused in the focusing plane P in a second direction orthogonal to the width L of the ligature 6 and tangent to the portion 20 of the ligature 6. The movement of the beams then takes place along the length of the ligature 6.

[0089] The scanning device 24 is configured to move the beams at a speed of between 0.1 m / s and 1000 m / s, for example at a speed of 3 to 10 m / s.

[0090] Preferably, the scanning device 24 comprises a galvanometric scanner 32.

[0091] The optical system 18, and in particular the galvanometric scanner, is shown in more detail in Figure 2.

[0092] The galvanometric scanner 32 comprises a first mirror 320 mounted to move relative to the focusing device 22 according to a first rotational movement around a first axis R1, a second mirror 322 mounted to move relative to the focusing device 22 according to a second rotational movement around a second axis R2 orthogonal to the first axis R1, and means 324 for galvanometric displacement of the first and second mirrors 320, 322 around the first and second axes R1, R2 respectively.

[0093] A rotation of the first and second movable mirrors 320, 322 around the first and second axes R1, R2 respectively is suitable for moving the beam, after focusing by the focusing device 22, here a lens, in the focusing plane P in two orthogonal directions, in particular according to the width and length of the ligature 6.

[0094] Alternatively, the scanning device 24 comprises a polygonal scanner. Preferably, when the laser 16 emits pulsed beams, the optical system 18 is configured to move and focus the pulsed beams received from the laser 16 such that the focused pulsed beams 15 impact the continuous portion 20 of the ligature 6 in a plurality of contiguous spots from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0095] Alternatively, when the laser 16 emits continuous beams, the optical system 18 is configured to move and focus the beams received from the laser 16 such that the focused beams 15 impact the continuous portion 20 of the ligature 6 along a line extending from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0096] During each scan, an energy density received at each position of the ligature portion 20 is adapted to ablate a layer of the ligature 6. Preferably, said layer has a thickness of at least 50 μm and at most equal to 50% of the thickness of the ligature 6, in particular between 50 μm and 200 μm.

[0097] Typically, the cutting unit 12 is configured to send onto the ligature portion 20 a beam 15 having an energy density of between 0.01 MW / cm 2 and 10 MW / cm 2 .

[0098] A groove 34, also called a cutting groove, is thus made on the portion 20 of ligature 6.

[0099] Preferably, as shown in FIG. 1, the cutting unit 12 further comprises a moving device 42 configured to, before each cutting step, move the optical system 18 relative to the coil 7 and the ligature 6.

[0100] The displacement device 42 is configured to move the optical system 18 relative to the coil 7 in a direction normal to the focusing plane P, such that the focusing plane P intersects the ligature portion 20, and / or parallel to the width L of the ligature 6.

[0101] Preferably, the control unit 14 is configured to control a movement of the optical system 18 by the movement device 42 as a function of the position of the detected ligature, as will be explained later.

[0102] Alternatively, the optical system 18 is fixed and comprises an adjustable element, for example motorized, capable of modifying parameters on the optical path to move the plane P so that it intersects a continuous portion 20 of the ligature 6.

[0103] The control unit 14 is configured to detect the presence and position of the ligature 6 relative to the optical system 18, and, from said detected position, to command the cutting unit 12 to carry out a series of at least two cutting steps of the continuous portion 20 of ligature 6.

[0104] At each cutting step, the control unit 14 is configured to command the cutting unit 12 to implement a cutting scan of the continuous portion 20 of ligature 6 and to detect the presence or absence of the ligature 6 around the coil 7 following the implementation of said scan, and selectively, carry out an additional cutting step if the presence of the ligature 6 is detected, or interrupt the series of cutting steps if the absence of ligature 6 is detected.

[0105] The scanning comprises the emission of focused beams 15 received on the continuous portion 20 of ligature, from the first transverse edge 61 to the second transverse edge 62 of the ligature, each cutting scan ablating the continuous portion 20 of ligature over a layer of thickness at most equal to 50% of the thickness of the ligature.

[0106] The control unit 14 comprises a ligature detection module 50 and a control module 52.

[0107] The detection module 50 is configured to detect the presence of the ligature 6 and the position of the ligature 6 relative to the optical system 18.

[0108] The detection module 50 comprises for example an image acquisition system 54, comprising or being connected to for example a camera 540, in particular a high-resolution camera.

[0109] Preferably, the detection module 50 further comprises a lighting system (not shown) improving the acquisition of images and the determination of the position of the ligature 6.

[0110] The detection module 50 further comprises a processing system 56 configured to determine, from each image acquired by the image acquisition system 54, the position of the ligature 6 relative to the optical system 18.

[0111] Alternatively or additionally, the detection module 50 comprises a laser system capable of detecting the presence of the ligature 6, for example due to the difference in height with the rest of the coil 7.

[0112] The control module 52 is configured to command the cutting unit 12, from said detected position, to carry out a series of at least two cutting steps of the continuous portion 20 of ligature 6, in order to produce a cutting furrow.

[0113] Figure 3 schematically represents the impact of a cutting laser beam 15 at the portion 20 of ligature 6 to be cut. Reference 70 designates the focal spot, which can be varied by varying the parameters of the focusing device 22. Reference 34 designates the kerf obtained.

[0114] Advantageously, when the coil 8 is surrounded by at least two ligatures 6, as in the embodiment of FIG. 1, the control unit 14 is configured to detect the number of ligatures, the presence and the position of each ligature 6 relative to the optical system 18, and, from the position of each ligature 6 detected, to command the cutting unit 12 to carry out a series of at least two cutting steps of a continuous portion 20 of each ligature 6.

[0115] When two ligatures 6 are located simultaneously in the working field of the focusing device 22, the cutting unit 12 is able to proceed with the cutting of said ligatures 6 at the same time and / or to proceed with the cutting of one after the other.

[0116] The control unit 14 is configured to, at each cutting step, command the cutting unit 12, by means of the control module 52, to implement a cutting scan of the continuous portion 20 of each ligature 6. The scan successively comprises, for each ligature 6 detected, an emission of focused beams 15 received on the continuous portion 20 of the ligature 6 detected from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0117] The control unit 14 is also configured to, at each cutting step, detect the presence or absence of each ligature 6 around the coil 7 following the implementation of the scanning, and selectively, carry out an additional cutting step if the presence of at least one ligature 6 is detected, or interrupt the series of cutting steps if the absence of ligatures 6 is detected.

[0118] According to a preferred embodiment, the cutting assembly 10 further comprises a protective enclosure 80 capable of receiving at least part of the coil 7 during cutting. The protective enclosure 80 defines an interior volume V intended to receive at least part of the coil 7 during cutting.

[0119] The cutting unit 12 is preferably arranged in said interior volume V, so that the beams 15 are located in the enclosure 80 which acts as a laser protection enclosure.

[0120] Said enclosure 80 further comprises a suction system 82 capable of sucking up and evacuating the smoke and particles coming from the cutting process. The enclosure 80 is for example capable of receiving the coil 7 in its entirety, as shown in FIG. 1, or only a portion of the coil 7, in particular a portion of the coil 7 at the level of which the portion 20 of ligature 6 to be cut is located. For example, the enclosure 80 is in the form of a cover capable of being applied to the coil 7 and of covering the portion 20 of ligature to be cut.

[0121] According to a preferred embodiment, the cutting assembly 10 further comprises a collection module 90 for ligature 6, capable of collecting a ligature 6 following its cutting. Said collection module 90 is configured to grasp the cut ligature 6 and convey the cut ligature away from the reel 7, in particular to a storage container (not shown).

[0122] For example, the collection module 90 comprises a mobile arm equipped with a gripping device and a system for controlling the mobile arm.

[0123] The system for controlling the mobile arm comprises, for example, an element for detecting the position of the cut ligature 6, such as a camera, and a control element configured to control the mobile arm from the position of the detected cut ligature 6, such that the gripping device grasps the cut ligature and conveys it to the storage container.

[0124] According to one variant, the movable arm comprises a shearing device, configured to shear the ligature into elements of reduced length, typically having a length between 1 mm and 200 mm, to convey the sheared elements to the storage container. The control element is thus configured to control the movable arm from the position of the detected cut ligature, such that the gripping device grasps the cut ligature, the shearing device shears the ligature into elements of reduced length and conveys these elements to the storage container.

[0125] According to a particular embodiment (not shown), the cutting assembly 10 also comprises a traction system capable of gripping the ligature 6 and exerting a force on it so as to move it away from the reel 7. Said gripping system thus pulls on the ligature 6 during its cutting, facilitating the breaking of the ligature 6.

[0126] According to a preferred embodiment, the cutting assembly 10 further comprises a holding system (not shown), for example a holding roller, capable of holding the reel 7 in shape when the tie(s) 6 is / are cut.

[0127] A method of cutting at least one ligature 6 according to the invention will now be described. The cutting method is implemented by a cutting assembly 10 according to the invention.

[0128] The cutting method preferably comprises a preliminary step of providing a coil 7 of a flat metal product 8 comprising at least one tie 6 enclosing said coil.

[0129] Preferably, a holding system, such as a holding roller, is arranged on or around the reel 7, to avoid sudden unwinding following the cutting of the tie(s) 6. Alternatively, the reel 7 is arranged so that the free longitudinal edge of the reel 7 is under the weight of said reel 7, to avoid sudden unwinding.

[0130] During a detection step, the control unit 14, and more particularly the detection module 50, detects the presence of at least one ligature 6 and the position of said ligature 6 relative to the optical system 18.

[0131] From the detected position, a series is carried out of at least two steps of cutting a continuous portion 20 of the ligature 6 from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0132] Each cutting step comprises a step of control, by the control unit 14, and more particularly by the control module 52, of the implementation by the cutting unit 12 of a cutting scan of the continuous portion 20 of ligature 6, and a step of implementation, by the cutting unit 12, of the cutting scan controlled by the control unit 14.

[0133] During the cutting scanning implementation step, the laser 16 emits beams.

[0134] Then, the optical system 18 moves and focuses said beams so that the focused beams 15 impact the continuous portion 20 of ligature from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0135] The scanning device 24 thus selectively deflects the beams emitted by the laser 16 onto the focusing device 22. The focusing device 22 focuses the beams deflected by the scanning device 24 into a focusing plane P perpendicular to a normal to the ligature portion 20 and intersecting the ligature portion 20.

[0136] In other words, during each scan, the beams emitted by the laser 16 are selectively deflected by the scanning device 24 to be focused by the focusing device 22, such that the focused beams 15 impact the ligature portion 20 from the first transverse edge 61 to the second transverse edge 62. Preferably, the distance between the focusing device 22 and the ligature 6 is greater than or equal to the width L of the ligature 6.

[0137] During each cutting scan, the scanning device 24 moves the focused beams 15 in the focusing plane P in at least a first direction substantially parallel to the width L of the ligature 6.

[0138] When the laser 16 emits pulsed beams, the cutting scan comprises the emission of focused pulsed beams received in a plurality of contiguous spots on the continuous portion 20 of ligature, from the first transverse edge 61 to the second transverse edge 62 of the ligature 6.

[0139] When the laser 16 emits continuous beams, the cutting scan comprises the emission of continuous beams by the laser 16 and the displacement and focusing by the optical system 18 of the beams such that the focused beams, during displacement, impact the ligature portion 20 along a line extending from the first transverse edge 61 to the second transverse edge 62 of the ligature.

[0140] During each scan, an energy density received at each impact position ablates a layer of the ligature with a thickness of at least 50 pm and at most equal to 50% of the thickness e of the ligature, in particular between 50 pm and 200 pm.

[0141] Thus, each cutting sweep is capable of ablating the continuous portion 20 of ligature over a layer of thickness at most equal to 50% of the thickness e of the ligature 6.

[0142] Thus, the bundles 15 do not completely cross the ligature 6.

[0143] A groove, also called a cutting groove, is made on the portion 20 of the ligature 6, said groove being made on a thickness less than the thickness e of the ligature 6, limiting the risks of damaging the coil 7, and in particular of forming scratches on it.

[0144] Following the implementation of the scanning by the cutting unit 12, the detection module 50 detects the presence or absence of the ligature 6 around the coil.

[0145] If the presence of ligature 6 is detected, an additional cutting step is performed.

[0146] If the absence of ligature 6 is detected, in other words if the detection unit does not detect a ligature, the series of cutting steps is interrupted.

[0147] Before carrying out the series of cutting steps or before at least one cutting step, a relative movement of the optical system 18 is preferably carried out with respect to the coil 7 as a function of the position of the detected ligature 6, in a direction orthogonal to the focusing plane P such that the focusing plane P intersects the portion 20 of ligature 6. Thus, the cutting unit 12 makes it possible to cut the ligature 6 layer by layer, from the external surface 64, until it is completely cut. The risks of damage to the coil 7 are therefore reduced, the energy sent to the ligature 6 being limited.

[0148] Preferably, before carrying out the series of cutting steps or before at least one cutting step, a relative movement of the optical system 18 is carried out with respect to the coil 7 as a function of the position of the detected ligature 6, in a direction parallel to the width L of the ligature.

[0149] Preferably, when the ligature 6 is made of plastic material, a cooling time for the ligature 6 is provided between each cutting step, to limit problems of melting of the ligature 6. Said time is typically between 10 ms and 500 ms.

[0150] Advantageously, due to the stresses exerted by the coil 7, and possibly by the traction system when it is present, on the ligature 6, said ligature 6 is capable of breaking before its complete cutting over its entire thickness, in particular up to its internal surface 63, by the cutting unit 12.

[0151] When the coil is surrounded by at least two ligatures 6, the method comprises the detection, by the control unit 12, of the number of ligatures 6 and the position of each ligature 6 relative to the optical system 18, and, from the position of each ligature 6 detected, the performance of a series of at least two steps of cutting a continuous portion 20 of each ligature 6.

[0152] When two ligatures 6 are simultaneously located in the working field of the focusing device 22, said ligatures 6 can either be cut at the same time or cut one after the other.

[0153] Each cutting step comprises the control, by the control unit 14, of the implementation by the cutting unit 12 of a cutting scan of the continuous portion 20 of each detected ligature 6, then the implementation, by the cutting unit 12, of the cutting scan controlled by the control unit 14.

[0154] When implementing the cutting scan, beams are emitted by the laser 16, then are moved and focused by the optical system 18, such that the focused beams 15, during the movement, successively impact the continuous portions 20 of the ligatures 6 detected from the first transverse edge 61 to the second transverse edge 62 of each ligature 6.

[0155] At the end of the implementation of the scanning by the cutting unit, the control unit 14, and more particularly the detection module 50, detects the presence or absence of each ligature around the coil 7. If at least one ligature 6 is detected, an additional cutting step is carried out.

[0156] If no ligature is detected, the series of cutting steps is interrupted.

[0157] When the assembly 10 comprises a collection module 90 for ligature 6, said collection module 90 grasps the cut ligature(s) 6 and conveys it / them away from the reel 7, in particular towards a storage container (not shown).

[0158] The cutting assembly 10 and the cutting method according to the invention thus make it possible to cut the ligatures 6 enclosing a coil efficiently and safely. Thus, the cutting of the ligatures 6 does not require the intervention of an operator near the coils 7, reducing the risk of injury.

[0159] The use of remote laser cutting allows for fast and precise cutting of the ligatures 6. The risk of damage to the coil 7 is thus reduced.

Claims

CLAIMS 1. Cutting assembly (10) of at least one ligature (6) enclosing a product (8), for example a coil (7) of a flat metal product (8), the ligature (6) having a thickness (e) of between 0.5 and 3 mm, the ligature (6) extending, along a width (L) between a first transverse edge (61) and a second transverse edge (62), the cutting assembly (10) comprising: - a cutting unit (12) configured to emit laser beams (15) focused on the ligature (6), comprising: a laser (16) capable of emitting beams, an optical system (18) configured to move and focus the beams received from the laser (16) such that the focused beams (15) impact a continuous portion (20) of the ligature (6) from the first transverse edge (61) to the second transverse edge (62) of the ligature (6), - a control unit (14), configured to detect the presence of the ligature (6) and the position of the ligature (6) relative to the optical system (18), and, from the position of the ligature (6) detected, to command the cutting unit (12) to carry out a series of at least two cutting steps of the continuous portion (20) of ligature (6), the control unit (14) being configured to, at each cutting step: command the cutting unit (12) to implement a cutting scan of the continuous portion (20) of ligature (6), the scanning comprising an emission of focused beams (15) received on the continuous portion (20) of ligature (6), from the first transverse edge (61) to the second transverse edge (62) of the ligature (6), each cutting scan ablating the continuous portion (20) of ligature (6) on a layer with a thickness at most equal to 50% of the thickness (e) of the ligature (6),detecting the presence or absence of the ligature (6) around the product (8) following the implementation of the scan, and selectively, carrying out an additional cutting step if the presence of the ligature (6) is detected, or interrupting the series of cutting steps if the absence of the ligature (6) is detected., 2. The cutting assembly (10) of claim 1, wherein the optical system (18) comprises a focusing device (22) and a scanning device (24), the scanning device (24) being configured to deflect selectively the beams emitted by the laser (16) onto the focusing device (22), the focusing device (22) being configured to focus the beams deflected by the scanning device (24) into a focusing plane (P) perpendicular to a normal to the ligature portion (6) and intersecting the ligature portion (20) (6).

3. Cutting assembly (10) according to claim 2, wherein a distance (d) between the focusing device (22) and the focusing plane (P) is greater than or equal to the width (L) of the ligature (6) between the first lateral edge (61) and the second lateral edge (62).

4. Cutting assembly (10) according to any one of claims 1 to 3, wherein: the laser (16) is capable of emitting pulsed beams, the optical system (18) is configured to move and focus the pulsed beams received from the laser (16) such that the focused pulsed beams (15) impact the continuous portion (20) of the ligature (6) in a plurality of contiguous spots from the first transverse edge (61) to the second transverse edge (62) of the ligature (6).

5. Cutting assembly (10) according to any one of claims 1 to 3, wherein: the laser (16) is capable of emitting continuous beams, the optical system (18) is configured to move and focus the beams received from the laser such that the focused beams (15) impact the continuous portion of the ligature (6) along a line extending from the first transverse edge (61) to the second transverse edge (62) of the ligature (6).

6. A cutting assembly (10) according to any one of claims 2 to 5, wherein the scanning device (24) comprises a galvanometric scanner (32) or a polygonal scanner.

7. Cutting assembly (10) according to any one of claims 2 to 6, wherein the focusing device (22) comprises at least one f-theta lens or flat field lens or a focusing mirror.

8. Cutting assembly (10) according to any one of claims 2 to 7, wherein the focusing device (22) has a focal distance greater than or equal to the width (L) of the ligature (6) between the first transverse edge (61) and the second transverse edge (62).

9. Cutting assembly (10) according to any one of claims 2 to 8, wherein the cutting unit (12) further comprises a displacement device (42) configured to, before each cutting step, move the optical system (18) relative to the product (8), in a direction orthogonal to the focusing plane (P), such that the focusing plane (P) intersects the portion (20) of ligature (6), and / or parallel to the width of the ligature (6), the control unit (14) being configured to control a movement of the optical system (18) by the displacement device (42) as a function of the position of the ligature (6) detected.

10. Cutting assembly (10) according to any one of claims 1 to 9, wherein during each scan, an energy density received at each position of the portion (20) of ligature (6) is adapted to ablate a layer of the ligature (6) with a thickness of at least 50 μm and at most equal to 50% of the thickness of the ligature (6), in particular between 50 μm and 200 μm.

11. Cutting assembly (10) according to any one of claims 1 to 10, wherein, the product (8) being surrounded by at least two ligatures (6), the control unit (14) is configured to detect the number of ligatures (6), the presence and the position of each ligature (6) relative to the optical system (18), and, from the position of each ligature (6) detected, to command the cutting unit (12) to carry out a series of at least two cutting steps of a continuous portion (20) of each ligature (6), the control unit (14) being configured to, at each cutting step: command the cutting unit (12) to implement a cutting scan of the continuous portion (20) of each ligature (6), the scan comprising successively, for each ligature (6) detected,an emission of focused beams (15) received on the continuous portion (20) of the ligature (6) detected from the first transverse edge (61) to the second transverse edge (62) of the ligature (6), detecting the presence or absence of each ligature (6) around the product (8) following the implementation of the scan, and selectively, carrying out an additional cutting step if the presence of at least one ligature (6) is detected, or interrupting the series of cutting steps if the absence of ligatures (6) is detected.

12. Cutting assembly (10) according to any one of claims 1 to 11, further comprising a protective enclosure (80) capable of receiving at least part of the product (8) during cutting.

13. Cutting assembly (10) according to any one of claims 1 to 12, further comprising a module (90) for collecting the ligature (6) following its cutting, configured to grasp the cut ligature (6) and convey the cut ligature (6) away from the product (8), in particular towards a storage container.

14. A method of cutting, by a cutting assembly (10) according to any one of claims 1 to 13, at least one ligature (6) enclosing a product (8), the ligature (6) having a thickness (e) of between 0.5 and 3 mm, the ligature (6) extending, along a width (L), between a first transverse edge (61) and a second transverse edge (62), the method comprising the detection, by the control unit (14), of the position of the ligature (6) relative to the optical system (18), and, from the detected position, the performance of a series of at least two steps of cutting a continuous portion (20) of the ligature (6) from the first transverse edge (61) to the second transverse edge (62) of the ligature (6), each cutting step comprising: the control, by the control unit (14), of the implementation by the cutting unit (12) of a cutting scan of the continuous portion (20) of ligature (6), the implementation, by the cutting unit (12),of the cutting scan controlled by the control unit (14), comprising the emission of beams by the laser (16) and the displacement and focusing by the optical system (18) of the beams such that the focused beams (15), during the displacement, impact the continuous portion (20) of ligature (6) from the first transverse edge (61) to the second transverse edge (62) of the ligature (6), each cutting scan ablating the continuous portion (20) of, ligature (6) over a thickness at most equal to 50% of the thickness (e) of the ligature (6), the detection, by the detection unit (50), of the presence or absence of the ligature (6) around the product (8) following the implementation of the scanning by the cutting unit (12), and selectively, the performance of an additional cutting step if the presence of the ligature (6) is detected, or the interruption of the series of cutting steps if the absence of ligature (6) is detected.

15. The cutting method according to claim 14, wherein the optical system (18) comprises a focusing device (22) and a scanning device (24), the scanning device (24) being configured to selectively deflect the beams emitted by the laser (16) onto the focusing device (22), the focusing device (22) being configured to focus the beams deflected by the scanning device (24) in a focusing plane (P) perpendicular to a normal to the portion (20) of ligature (6) and intersecting the portion (20) of ligature (6), during each scan, the beams emitted by the laser (16) are selectively deflected by the scanning device (24) to be focused by the focusing device (22), such that the focused beams impact the portion of ligature (6) from the first transverse edge (61) to the second transverse edge (62).

16. Cutting method according to claim 15, wherein a distance (d) between the focusing device (22) and the product (8) is greater than or equal to the width (L) of the ligature (6) between the first transverse edge (61) and the second transverse edge (62).

17. Cutting method according to any one of claims 14 to 16, in which the laser (16) emits pulsed beams, the cutting scan comprises the emission of focused pulsed beams (15) received in a plurality of contiguous spots on the continuous portion (20) of ligature (6), from the first transverse edge (61) to the second transverse edge (62) of the ligature (6).

18. A cutting method according to any one of claims 14 to 16, wherein: the laser (16) emits continuous beams, the cutting scan comprises the emission of continuous beams by the laser (16) and the displacement and focusing by the optical system (18) of the beams such that the focused beams (15), during the displacement, impact the portion (20) of ligature (6) along a line extending from the first transverse edge (61) to the second transverse edge (62) of the ligature (6).

19. Cutting method according to any one of claims 15 to 18, comprising, before carrying out the series of cutting steps or before at least one cutting step, a relative movement of the optical system (18) with respect to the product (8) as a function of the position of the ligature (6) detected, in a direction orthogonal to the focusing plane (P) such that the focusing plane (P) intersects the portion (20) of ligature (6) and / or in a direction parallel to the width (L) of the ligature (6).

20. Cutting method according to any one of claims 14 to 19, wherein during each scan, an energy density received at each position of the portion (20) of ligature (6) ablates a layer of the ligature (6) with a thickness of at least 50 pm and at most equal to 50% of the thickness (e) of the ligature (6), in particular between 50 pm and 200 pm.

21. Cutting method according to any one of claims 14 to 20, wherein, the product (8) being surrounded by at least two ligatures (6), the method comprises the detection, by the control unit (14), of the number of ligatures (6) and the position of each ligature (6) relative to the optical system (18), and, from the position of each ligature (6) detected, the performance of a series of at least two cutting steps of a continuous portion (20) of each ligature (6), each cutting step comprising: the control, by the control unit (14), of the implementation by the cutting unit (12) of a cutting scan of the continuous portion (20) of each ligature (6) detected, the implementation, by the cutting unit (12), of the cutting scan controlled by the control unit (14), comprising the emission of beams by the laser (16) and the displacement and focusing by the optical system (18) of the beams such that the focused beams (15), during the displacement, successively impact the continuous portions (20) of the ligatures (6) detected from the first transverse edge (61) to the second transverse edge (62) of each ligature (6), the detection, by the detection unit (50), of the presence or absence of each ligature (6) around the product (8) following the implementation of the scanning by the cutting unit (12), and selectively, the performance of an additional cutting step if the presence of at least one ligature (6) is detected, or the interruption of the series of cutting steps if the absence of ligatures (6) is detected.

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