Laser marking device, installation and associated process

Abstract

Title: Laser marking device, installation and associated method The present invention relates to a device (1) for laser marking containers (2), in particular bottles or flasks made of thermoplastic material, of the type comprising at least one body (23), a shoulder (24) in the extension of said body (23) at an upper end thereof, a neck (21) in the extension of the shoulder (24), and a base (22) at the lower end of said body (23), said device (1) comprising at least: - a plurality of laser marking stations (3), each station (3) comprising along an optical path at least one optical laser marking head (30) equipped with a laser head unit (300) and an optical system (320) for focusing a laser beam (31) in order to generate a mark (310) at the level of at least one marking zone (20) of each container (2) to mark said zone (20),and - control means (4) connected to the marking stations (3) and comprising a laser processing unit (40) and the power supply means (41) for the laser marking stations (3). The device is characterized in that it comprises a carousel (5) with a vertical axis of rotation X driven in rotation by at least one motor relative to a frame (7) via a bearing means (70), said carousel (5) comprising at least: - a first platform (50), said first platform (50) supporting a plurality of retaining members (54) for positioning said container (2) along an axis substantially parallel to the vertical axis of rotation X of said carousel (5),- a barrel (53) supporting the plurality of marking stations (3) such that each optical system (320) is located opposite a container (2) held by a retaining member (54). The present invention also relates to a container marking method and a container marking installation (2). Figure for the abstract: Figure 1,

Description

Title of the invention: Laser marking device, installation and associated method

[0001] Technical Field: The invention relates to a marking device, a marking installation, and a laser marking method for containers. State of the art

[0002] It is known to include information and decorations on containers, especially plastic bottles. The information on a container might include, for example, the expiration date of the contents or the formula of the product inside. Decorations might include, for example, the manufacturer's logo.

[0003] It is well known to include this information and decorations on paper or plastic labels. The labels are affixed to the final container after the container forming stage, that is, when the containers are formed into their final shape.

[0004] However, labeling containers has many drawbacks. Indeed, manufacturing the labels, printing them, and affixing them to the containers represents a high cost, especially for the mass production of containers. Furthermore, the label is likely to be torn off during handling of the container. The end user can then no longer access certain important information, such as the expiration date. Finally, recycling plastic containers is complicated by the presence of labels and adhesives. Indeed, to promote recycling, it is best to ensure that containers, labels, and other components are collected separately according to their different materials. However, manually removing labels from containers for separate collection can be a tedious task. Therefore, label removal is one of the factors hindering successful recycling.

[0005] For the inscription of important information, methods of marking the container wall have already been proposed. For example, it is known to print certain important information directly onto the container wall using a special ink. However, this printing method is not satisfactory because, for hygiene reasons, the ink used for marking must dry almost instantly, and it must also remain on the surface of the wall without penetrating the inside of the container. a migration phenomenon. As a result, the ink has a specific composition which is very expensive to manufacture. Furthermore, the use of ink also complicates the recycling processes for plastic containers.

[0006] To circumvent these problems, a marking process involving engraving the container wall has also been proposed. The engraving is generally carried out using a carbon dioxide laser. Such a marking process is achieved by removing material from the container wall, notably through evaporation. As a result, the wall has a locally reduced thickness. However, in the interest of economy and environmental protection, efforts are being made to reduce the thickness of container walls. This makes it possible to produce containers using less plastic material than before. However, removing material from a very thin wall risks weakening it to the point of cracking the container under the slightest stress.

[0007] Other known laser marking devices have quality problems with respect to parts or substrates that are not flat and / or that have a variable focal length with respect to the optics, as is the case for a large majority of containers. In such a case, the markings on the substrate are blurry, vary in height or spacing and might otherwise be illegible, thus rendering the characters unsatisfactory to use.

[0008] To solve these marking quality problems while remaining compatible with high-volume container production, the present invention proposes to provide a laser marking device that guarantees optimal marking position on the container while allowing containers to be marked at a rate compatible with the productivity levels required in the industrial sector.

[0009] The invention advantageously provides a carousel with a vertical axis of rotation allowing synchronized rotary movement of containers and marking stations. The fact that the marking stations and containers rotate synchronously around the same vertical axis of rotation allows the laser beam to be focused at a defined, known, and virtually constant distance. Thus, the focal length D corresponds to the ideal focal point within the marking area, without the container's manufacturing tolerances or orientation altering the distance between the laser marking head and the marking area.

[0010] These characteristics allow the device according to the invention to operate at an industrial rate, on the order of, for example, 8000 to 100000 markings per hour.

[0011] The invention relates first to a laser marking device for containers, in particular bottles or flasks made of thermoplastic material, of the type comprising at least one body, a shoulder extending from said body at one upper end thereof, a neck extending from the shoulder, and a base at the lower end of said body, said device comprising at least: - a plurality of laser marking stations, each station comprising along an optical path at least one laser marking optical head equipped with a laser head unit and an optical system for focusing a laser beam to generate a mark at at least one marking area of ​​each container to mark said area, and - control means connected to the marking stations and including a laser processing device and the means for supplying the laser marking stations.

[0012] The device is characterized in that it comprises: - a carousel with a vertical axis of rotation X, driven in rotation by at least one motor relative to a frame and via a rolling means, the carousel comprising at least: - a first platform, the first platform supporting a plurality of retaining devices for positioning said container along an axis substantially parallel to the vertical axis of rotation X of said carousel, and - a barrel supporting the plurality of marking stations such that each optical system is located opposite a container held by a retaining device.

[0013] In embodiments, the working distance between the axis of the container and the optical head is constant or substantially constant.

[0014] Advantageously, at least one optical head of each marking station is capable of moving the focal point of the laser beam in a horizontal plane and / or in a vertical plane and / or in a longitudinal plane relative to at least one marking area.

[0015] According to one possible variant, the shaft includes means for vertically moving each marking station or each optical head, so that each of the stations or each of the optical heads can move vertically along said shaft.

[0016] In embodiments, the first tray and / or each retaining member includes means for vertically moving a container.

[0017] In some embodiments, the carousel comprises a second platform, called the lower platform, said lower platform being located below the first platform, called the upper platform, and driven in rotation in a synchronous manner with the second platform, and, for each container, the retaining elements comprise on the one hand, at the level of the upper plate, a gripping means to hold a container, preferably by the neck and, on the other hand, at the level of the lower plate, a plate on which the bottom of said container rests.

[0018] In embodiments, the carousel includes a third platform whose axis of rotation is coaxial with the axis of rotation of the first platform, the third platform supporting the control means.

[0019] According to another possible variant, the first tray and / or the second tray and / or the barrel are in one piece.

[0020] In some embodiments, the control means are located on the upper part of the third platform.

[0021] According to a final possible variant, each marking station comprises two optical heads placed head to tail in each of said stations, so that the optical systems of the two optical heads are superimposed in order to simultaneously mark a marking area located in the upper part of the container and an area located in the lower part of said container.

[0022] Advantageously, each marking station includes a pulsed laser optical head with a wavelength between 800 and 2000 nanometers.

[0023] The invention also relates to an installation comprising: - a laser marking device as described above, - a container processing station located upstream of the marking device, the processing station supplying the device directly or indirectly by means of a transfer wheel at a loading point, - a transfer wheel at a discharge point to release the marked containers directly or indirectly to a downstream conveying means.

[0024] In some embodiments, the installation includes a system for inspecting marked containers.

[0025] The invention also relates to a marking method comprising at least the following steps: - a first step consisting of carrying out a treatment on said containers, preferably filling and capping said containers, - a second step consisting of rotating said containers, preferably filled and sealed, around a vertical axis around which laser marking stations are rotated, in a manner synchronized with said containers, and - a third step consisting of marking said containers during rotation.

[0026] Advantageously, the marking step takes place during rotation over an angular sector of less than 360 degrees around the vertical axis.

[0027] In embodiments, the marking step is carried out during rotation over an angular sector of less than 360 degrees around the vertical axis.

[0028] In some embodiments, the marking process further comprises: - after the container processing step, preferably filling and capping, a container loading step at a loading point, - following the marking step, an unloading step at a container unloading point, the marking step being carried out between the loading point and the unloading point of the marked containers at at least one marking area before starting a new cycle including at least the process steps.

[0029] In embodiments, after the loading step, and before or during the marking step, the containers are moved vertically.

[0030] In some embodiments, the marking step is carried out by a pulsed laser in the near-infrared.

[0031] Brief description of the figures: The invention will be better understood from the description below, which is based on possible embodiments, explained in an illustrative and in no way limiting manner, with reference to the accompanying figures, in which:

[0032] [Fig-1] schematically represents a perspective view of the device;

[0033] [Fig.2] represents a vertical cross-sectional view of the device;

[0034] [Fig.3] represents a detailed view of a marking station and a container;

[0035] [Fig.4] schematically represents a detailed view of the container retention devices;

[0036] [Fig.5] schematically represents a side and detailed view of a station for applying a laser beam to a held container;

[0037] [Fig.6] schematically represents an embodiment in which the device comprises two scan heads;

[0038] [Fig.7] schematically represents a top view of the device according to the invention and in particular of the rotation of the plates;

[0039] [Fig.8] schematically represents an installation with an inspection system and

[0040] [Fig.9] schematically represents an example of implementation of the process according to the invention.

[0041] Detailed description: In the following description, elements having an identical structure or analogous functions will be designated by the same reference.

[0042] The invention relates firstly to a device 1 for laser marking of containers 2, represented schematically in [Fig.1]. In the context of the invention, container 2 is a bottle or flask. It is made of plastic. Preferably, the container is made of polyethylene terephthalate, hereinafter referred to as PET. Container 2 can therefore be rigid or semi-rigid. It is intended to contain a fluid, a liquid, powders, or granules, particularly of a food or cosmetic type. Container 2 can have any shape, symmetrical or asymmetrical. It can have a rounded cross-section, generally circular or ovoid, or a polygonal cross-section, particularly rectangular or square. Preferably, said containers 2 have a rounded cross-section, particularly a generally circular one.

[0043] The containers 2 have at least one body 23, a shoulder 24 extending from said body 23, and a base 22 at the end of said body 23. The body 23 of a container 2 includes a peripheral wall. The wall of a container 2 may be cylindrical, rectangular, or of any shape. In a normal orientation, the container 2 rests on its base 22, and the principal direction is vertical. The base 22 may be generally flat, petal-like, or otherwise shaped. Preferably, the containers 2 are obtained by forming from thermoplastic preforms. Such preforms are generally obtained by injection molding.

[0044] In the context of the invention, the container 2 has at least one marking area 20 located on its wall. At least one marking area 20 is intended to receive a mark 310, made by laser marking. The marking zone 20 can be oriented so that the mark 310 is parallel to the main direction of the container 2, or orthogonal, or have any possible orientation with respect to the wall 25 of the container 2 along its main direction.

[0045] The device 1 according to the invention comprises at least a plurality of laser marking stations 3. A laser marking station 3 includes along an optical path at least one optical head 30 which is connected to control means 4 of the station 3. The control means 4 include the laser processing device 40 and the power supply means 41 of the stations 3. The laser processing apparatus 40, or laser 40, includes a light emission source, or pumping source, and optionally an amplifying medium for emitting laser light in the form of a laser beam 31. According to one possible variant, the optical head 30 includes the amplifying medium.

[0046] The optical head 30 is connected to the laser processing unit 40 by a network of optical fibers and electrical links, or optical channels 600. The optical channels 600 comprise at least one optical fiber which is an optical waveguide for the laser light emitted, for example, by the laser processing unit 300. According to one possible variant, the amplifying medium is incorporated into the optical channel 600 in the form of a doped optical fiber into which the light emitted from the device 40 is injected towards a laser head unit 300. Station 3 controls the optical head 30 and the emission of the laser beam 31 from the control means 4.

[0047] Thus, the optical head 30 comprises a laser head unit 300 and an optical system 320, removably mounted on said laser head unit 300. Preferably, the laser head unit 300 emits a laser light beam 31 directed in a predetermined direction.

[0048] The optical system 320 includes at least one mirror for moving the laser beam 31 in a horizontal plane and / or in a vertical plane, and optionally a lens at the optical output 321 of the optical system 320, for focusing the beam of light in the plane and at the level of at least one marking zone 20, to generate a mark 310 at the level of said at least one zone 20. By optical path, we mean the path taken by the laser light from its emission from, for example, the laser processing device 40 to the optical output 321 of the optical system 320 in the form of a laser beam 31. In other words, at least one marking zone 20 corresponds to a treatment surface within which the laser beam 31 is applied in a horizontal and / or vertical direction. Depending on the type of mark 310 to be applied, the focal point of the laser beam 31 is not necessarily located directly on the wall of the container 2; that is to say, in a longitudinal direction relative to at least one marking zone 20 of said container 2, the focal point of the laser beam 31 may be located, in particular, above the wall, directly on the wall, at the level of the outer skin of the container 2, or inside said wall, for example at the level of the inner skin of said container 2, or even beyond.

[0049] In embodiments, the device 1 includes a fixed lens, said fixed lens being of the spherical type, flat field, or preferably of the F-theta type in order to maintain the dimension of the focal point relatively constant in the plane.

[0050] According to one possible variant, the laser head unit 300 and the optical system 320 are in one piece.

[0051] In embodiments, the means 4 for controlling the laser station 3 comprise a plurality of cooling units, not shown.

[0052] Within the framework of the invention, laser marking on at least one area 20 of a container 2 can be done in particular by local modification of the refractive index, and / or by local modification of the transmission index, and / or by local modification of the reflection index of the material of said container 2.

[0053] Each marking station 3 includes at least one optical head 30 which emits and focuses the laser beam 31. According to one possible variant, said at least one optical head 30 generates the optical beam 31.

[0054] In embodiments, the optical head 30 includes means (not shown) controlled to move the emitted beam 31, for example by means of movable mirrors relative to the marking area 20 of a container 2, in the direction of the optical axis or perpendicular to it.

[0055] According to one possible variant, the optical head 30 includes means (not shown) controlled to move the focal point of the emitted beam 31, for example by means of movable lenses relative to the marking area 20 of a container 2, in the direction of the optical axis or perpendicular to it.

[0056] The control means 4 include an electronic unit 400 for controlling the movement of the laser beam 31. The unit 400 can be parameterized at will to modify the mark 310 to be inscribed; for example, it is a numerical control. The parameters to be modified relate, for example, to the coordinates of the movement of the beam 31, the speed of movement of the beam 31, etc. The 310 mark can consist of characters, patterns, barcodes, etc. Typically the distance DI between the exit of beam 31 and the marking area 20 of container 2 can vary, depending on the shape and / or dimensions of container 2.

[0057] The laser beam 31 can trace the mark 310 indifferently according to a vector mode, that is to say by continuous tracing, or according to a matrix mode, that is to say by tracing point by point.

[0058] In some embodiments, the optical head 30 comprises a pulsed laser unit 300. The unit 300 generates the laser beam 31 which is then scattered by the optical system 320. Preferably, the wavelength of the emitted laser is between 800 and 2000 nanometers (nm). In embodiments, and depending on the type of marking required, it may also be possible to select a laser emitting a beam of different wavelengths, for example of the Ytterbium, Erbium, Thulium type fiber laser, or of the Nd-YAG or Nd:YVO4 solid type. Depending on different possible configurations, the laser light is emitted in particular from device 40, and / or optical channel 600 or from laser unit 300. As a possible alternative, the Nd-YAG laser is configured to emit a laser beam 31 with a wavelength of 532 nm emitting in the visible range, more precisely in the color green.

[0059] According to yet another embodiment of the invention, the laser of the Nd-YAG marking station 3 is configured to emit a beam 31 at a wavelength in the near ultraviolet, for example 355 nm. Preferably, the wavelength of the emitted laser beam 31 is therefore between 1000 and 1100 nm, or between 1500 and 1600 nm, or between 1900 and 2000 nm, depending on the type of containers 2 to be marked and / or the type of mark 310 to be applied to the marking area 20 of a container 2.

[0060] It has been observed that the PET wall marking areas 20 of the container 2, targeted by the near-infrared laser beam 31 with appropriate power and / or exposure time, undergo a phenomenon known as "foaming." Foaming consists of melting the material and generating bubbles that expand, forming a bead on the surface. These bubbles remain trapped during cooling. The material's resistance is only slightly affected. Furthermore, the legibility of the resulting marking 310 is significantly improved because the gas bubbles in the material reflect light diffusely.

[0061] Preferably, the marking station 3 uses a laser with a pulsed operating mode to generate short pulses of a duration of less than 500ns (nanoseconds) and of peak power on the order of kW (kilowatt) to several tens of kW depending on the marking desired and focusing the beam in the vicinity of the wall of the container 2, at the level of the marking zone 20.

[0062] According to other, unrepresented embodiments of the invention, other types of lasers may be used within the scope of the present invention. As explained previously, the laser is selected and adjusted to allow marking of the thermoplastic material wall, either on the surface or in depth, without, however, engraving the wall.

[0063] The device 1 according to the invention is characterized in that it comprises a carousel 5 with a vertical axis of rotation X, said carousel 5 being driven in rotation by at least one motor relative to a frame 7. A schematic view of an example embodiment of the device 1 and the carousel 5 is visible in [Fig.1].

[0064] The rotation of the carousel 5 relative to the frame 7 is achieved by means of a rolling means 70.

[0065] In embodiments, the carousel 5 is supported by a rotating chassis 6, rotating around the vertical axis of rotation X, in the form of an orientation ring which includes the bearing means 70. The rolling means 70 can, for example, be made in the form of two rings that can be rotated relative to each other, each ring having a raceway, and the ring also having a rotation device consisting of rolling elements or bodies (such as balls or ball bearings) interposed between the two raceways and a device of fixing the constituent elements of the crown to prevent them from separating while allowing the relative rotation of the two rings. The carousel 5 can then be rotated around the vertical axis of rotation X by connecting one ring to the frame 7, with the carousel 5's chassis 6 supported by the other ring. Thus, the carousel 5 can rotate relative to the frame 7. The ring connected to the frame 7 is called the fixed ring, and the other ring is called the rotating ring.

[0066] In some embodiments, the frame 6, in the form of a slewing ring, may include external teeth mounted on the rotating ring. According to one possible variant, the rotating frame 6 is cup-shaped and mounted on the rotating ring, for example, through blind or through mounting holes, smooth or tapped. Various machine components, not shown, are mounted on this cup, the assembly forming a carousel. As an illustration, on a machine of the applicant, the rotating mass equipped with the organs of device 1 (optical heads 30, control means 4, plate 50, 51, 52, shaft 53, etc.) can have a weight of around ten tonnes for a rotation speed of the carousel, and therefore of the rotating ring, of around thirty revolutions per minute. The rotating ring and therefore the carousel 5 are driven in rotation by a motor, generally not directly, but via gear and / or belt mechanisms.

[0067] In some embodiments, the rotating chassis 6 is in the form of a column.

[0068] The carousel 5 of the invention comprises at least one first platform 50, or platform. The axis of rotation of at least one platform 50 is coaxial with the axis of rotation of the carousel 5. The 50 plate can be of any shape, but is preferably circular. As seen in [Fig.2], the platform 50 supports a plurality of retaining members 54 to position a container 2 along an axis substantially parallel to the vertical axis of rotation X of the carousel 5. In other words, a container 2 is held by a retaining member 54 and is driven in rotation by the first platform 50 of the carousel 5.

[0069] As seen in [Fig.1] or 2, the carousel 5 also includes a shaft 53.

[0070] The shaft 53 supports the plurality of marking stations 3 such that each optical system 320 is located opposite a container 2, itself held by a retaining member 54. Preferably, the diameter of the barrel 53 is less than the diameter of the first plate 50 in order to facilitate the implementation of device 1.

[0071] As schematically shown in [Fig. 7], the containers 2 and the optical heads 30 are both driven in rotation about a vertical axis of rotation X relative to the frame 7. The synchronized rotation of the marking stations 3 and the containers 2 and The vertical position of the container 2 opposite the optical system 320 of an optical head 30 is particularly advantageous. Indeed, the working distance D2 between the optical system 320 and the marking zone 20 of the container 2 is then constant or nearly constant: the containers 2 are immobilized during marking, as are the optical systems 320, and the marking produced is of high quality.

[0072] The marking stations 3, the control means 4 and the containers 2 are therefore driven in rotation in a synchronized manner with respect to the frame 7. The carousel 5 also includes a rotating 60 joint that supplies electricity to the 4L power sources For this purpose, the rotary joint 60 includes a rotating electrical collector, located at the head of said rotary joint 60, which is powered by a fixed electrical cable. Conventionally, the rotating electrical collector has tracks, fixed or rotating, on which rotating or fixed fingers respectively bear elastically. The entire assembly is housed under a casing, not shown, which is fixed to the frame 6 and held in place by an anti-torque structure integral with the fixed frame 7. Preferably, the barrel 53 is hollow so as to accommodate the rotating joint 60 in this hollow central part.

[0073] Thus, the invention makes it possible to mark the containers 2 during their rotation, which is extremely advantageous. It is then possible to mark containers 2 at a high rate, on the order of 8,000 to 100,000 markings per hour.

[0074] In embodiments, at least one optical head 30 of each marking station 3 is capable of moving the laser beam 31 in a horizontal plane and / or in a vertical plane. Preferably, the laser beam 31 is emitted in a direction orthogonal or substantially orthogonal to the vertical axis of rotation X of the carousel 5. The vertical plane corresponds to the plane passing through the vertical axis of rotation X of the carousel 5, and the horizontal plane corresponds to the plane perpendicular to the axis of rotation X of the carousel 5.

[0075] In some embodiments, the shaft 53 of the carousel 5 includes means for vertically moving each marking station 3 or each laser head 30, such that each of said stations 3 or each of said laser heads 30 can move vertically along the shaft 53, for example by means of slides placed on the shaft 53 and an actuation means (not shown). This has the advantage of allowing the optical system 320 to be positioned opposite the marking zone 20 of a container 2. Indeed, the type of container 2, its dimensions, its shape, can change, and it is then necessary to adjust the relative positioning of the optical system 320 and the marking zones 20. This adjustment can be done, for example, automatically via an electronic control unit 400 included in the control means 4, by a mechanical cam adjusted by an operator or by means of an actuator, or manually by the operator.

[0076] According to another possible embodiment, the first plate 50 and / or each retaining member 54 includes means for vertically moving a container 2. This embodiment is preferred because it is simpler to implement. Similarly, the adjustment of the vertical position of the marking zone 20 of the container 2 can be done, for example, automatically via an electronic control unit 400, or by a cam. This vertical positioning is preferably carried out before the marking of containers 2.

[0077] In some embodiments, the carousel 5 includes a second platform 51. The second plate 51 is called the lower plate because it is located below the first plate 50, called the upper plate. The second plate 51 is driven in rotation synchronously with the first plate, relative to the frame 7. The second plate 51 then supports holding means 54 in the form of a plate 541, on which the bottom 22 of a container 2 rests. The container 2 is then held firmly in position from above, preferably by its neck 21, by a gripping means 540; and from below, more particularly by its bottom 22, which rests on said plate 541. This embodiment, visible in [Fig.4], is very advantageous because it ensures that the container 2 is held in position during its rotation and therefore during its marking. In addition, the 541 plate contributes to the centering and vertical positioning assistance of the container 2.

[0078] In embodiments, the carousel 5 includes a third platform 52, whose axis of rotation is coaxial with the axis of rotation of the first platform 50. The third platform 52 supports the control means 4 and is preferably, but not exclusively, located above the first platform 50. It is particularly advantageous to position the control means 4 on the upper part of a third platform 52 located in the upper part of the drum 53. Indeed, this allows a primitive of movement of the containers 2 to be smaller than that of the control means 4. Also, this helps to avoid possible leakage problems, in cases where the containers 2 are filled before marking.

[0079] Fig. 1 shows an illustrative example in which the carousel 5 comprises three platforms 50, 51, 52, the control means 4 being located on the upper part of the third platform 52.

[0080] Figure 2 also shows an embodiment in which the carousel 5 includes a first platform 50, a second platform 51 and a third platform 52. The first platform 50 supports the vertically movable retaining means 540, while the second platform 51 supports a plate 541, also vertically movable. Preferably, only the plate 541 is vertically movable. Indeed, it is preferable to position the container 2 vertically by pushing it from its base 22. In other words, in a preferred embodiment, only the plate 541 is actuated, or motorized, to move the container 2 vertically, the retaining means 540 then performing so-called passive translations.

[0081] Preferably, and as illustrated in [Fig.2] in particular, the third plate 52 is located in the upper part of the shaft 53 and supports the control means 4, and in particular the laser processing device 40 and the power supply means 41. The rotating joint 60 and optical channels 600 which electrically connect the different elements can also be seen.

[0082] In the embodiment shown in [Fig.2], the different platforms are connected to the barrel 53. It is also possible to link together two or three platforms 50, 51, 52 in the form of a console to be assembled on a shaft 53 of a carousel 5. Thus, according to one possible variant, the first tray 50 and the second tray 51 and / or the third tray 53 are in one piece.

[0083] In embodiments, and as seen in particular in [Fig.3], each marking station 3 comprises two optical heads 30. The two optical systems 320 can be superimposed along an axis parallel to the rotation axis X of the carousel 5 in each station 3, in order to simultaneously mark a marking zone 20a located in the upper part of the container 2 and a zone 20b located in the lower part of said container 2, in its normal orientation, i.e. when it rests on its bottom 22. Figure 3 shows an example of an embodiment in which each marking station 3 comprises two optical heads 30, the two optical systems 320 being arranged head to tail.

[0084] According to another possible embodiment, illustrated in [Fig. 6], the station 3 comprises two optical systems 320a, 320b angularly offset by an angle α about an axis orthogonal or substantially orthogonal to the vertical axis of rotation X of the carousel 5. The angle α is, for example, between 30 and 160 degrees. Each optical system 320a, 320b performs the marking respectively on an area 20a, 20b. Optionally, the areas 20a and 20b can be positioned at the same height along an axis parallel to the axis of rotation X of the carousel 5. This embodiment is particularly advantageous because it allows a mark 310 to be made over a larger part of the circumference of a container 2.

[0085] The invention further relates to a container marking installation 100 2, comprising a laser marking device 1 as described above.

[0086] The installation 100 also includes a container processing station 10 2 located upstream of the device 1. The processing station 10 supplies the device 1 directly or indirectly from the outlet of a transfer wheel 8, at the level of a loading point 80. Such a processing station 10 can be, for example, a filler, a capper, a blower, a labeler, or any other container processing station 2 on a packaging line.

[0087] Advantageously, the installation 100 allows a continuous supply of containers 2.

[0088] An installation 100 according to one possible embodiment is schematically represented in top view in [Fig.8]. Containers 2 travel on an upstream conveyor 102 from a processing station 10, for example, a filling and capping machine. The containers 2 are then transferred, preferably continuously, via an upstream transfer wheel 8, to a loading point 80, at the device 1 according to the invention. In particular, the containers 2 are gripped by retaining elements 54. The plurality of laser marking stations 3 can be seen around the entire periphery of the drum 53 of the carousel 5. According to the variant illustrated in [Fig.8], the installation 100 also includes an intermediate wheel 800 between the upstream conveying means 102 and the transfer wheel 8.

[0089] The stations 3 are positioned opposite the held containers 2, such that the laser beam 31 can be directed towards a marking area 20 on the containers 2, preferably orthogonally or substantially orthogonally to the axis of rotation X of the carousel 5. The direction of rotation is schematically represented by a circular arrow, which does not define the direction of rotation of said carousel 5 within the scope of the invention. In other words, the carousel 5 can rotate about its vertical axis of rotation X in either direction.

[0090] During the rotation of the containers 2 in a manner synchronized with the rotation of the marking stations 3, the containers 2 are therefore marked, that is to say that a mark 310 is affixed to at least one marking area 20 by means of a laser beam 31 emitted and diffused by the marking stations 3.

[0091] Following the marking, and as shown in [Fig. 8], the marked containers 2 are transferred from an unloading point 90 via a downstream transfer wheel 9. The containers 2 are, for example, placed onto a downstream conveyor 101.

[0092] Preferably, the unloading of the containers 2 by means of the downstream transfer wheel 9 is also continuous. In other words, the installation 100 allows continuous marking of the containers 2, with a continuous supply of containers 2 to device 1 from a processing station 10 of the containers until their unloading onto a conveying means 101 downstream. In other words, preferably, the carousel 5 of device 1 is driven in continuous rotation. This is particularly advantageous because it allows the marking of containers 2 to be carried out at a sustained rate.

[0093] As seen in [Fig. 8], the installation 100 may also include, in some embodiments, an inspection system 11. Such an inspection system 11 comprises at least one camera and a control unit (not shown) for verifying whether the mark 310 is compliant. In case of non-compliance, the container 2 must be destroyed or at least discarded to prevent further processing. The installation 100 may include means 110 for ejecting a container 2 whose marking 310 is not compliant. For these control purposes, in embodiments, the installation 100 includes a central control unit 12 for entering information concerning the type of container 2, the format, the type of mark 310 to be affixed, the location of the marking zones 20, 20a, 20b, etc. According to one possible variant, the central control unit 12 communicates with the electronic control unit 400 of the means 4. In embodiments, the central control unit 12 comprises: - a database 120 in which are written programs for controlling the marking device 1 and possibly other container processing stations 2, said database 120 being recorded in a memory device or stored on an independent server, - a processor connected to the memory to apply the instructions of the programs and - a communication interface connected to the processor for communication at least with the electronic unit 400 of the control means 4. According to one possible variant, the central control unit 12 includes a computing unit enabling the generation of real-time instructions based on measurements taken by different sensors, for example a sensor measuring the height of a container 2.

[0094] In embodiments, the central control unit 12 transmits information in the form of instructions to the control means 4 via the rotary joint 60. The information transmitted relates, for example, to at least one marking zone 20, the characteristics of the mark 310, the marking parameters, etc. The electronic control unit 400 acts as a slave controller controlled by the central unit 12, known as the master unit. The electronic control unit 400 is programmed to drive device 1 for the complete execution of a marking cycle.

[0095] The central control unit 12 can also allow the setting of the direction of rotation of the carousel 5, or its speed of rotation.

[0096] The master control unit can therefore be connected to other slave controllers, to possibly operate the adjustment of the rotation speed of the transfer wheels 8, 9, or of the conveying means 101 and 102.

[0097] The central control unit 12 can also be connected to an inspection system 11 to allow setting the level of conformity of the mark 310 of a container 2. Conformity can be, for example, legibility, positioning of the mark, etc. According to one possible variant, the inspection system 11 transmits information concerning the quality of the marking to the central control unit 12, which can then send instructions to the electronic control means unit 400 4, for example aimed at correcting the height adjustment of the mark 310, or any other parameter related to the marking.

[0098] Advantageously, the central control unit 12 includes various sensors, notably speed sensors, the information from which is stored in the database 120 or transmitted to a processing unit of the central control unit 12. For example, the database 120 of the central control unit 12 records the speed parameters of the transfer wheels 8, 9, of the carousel 5, and information concerning the formats of the containers 2 to be marked, for example their dimensions and / or shape.

[0099] In some embodiments, the central control unit 12 also transmits instructions to the electronic unit 400 in order to transmit instructions to the holding elements 54 and / or the marking stations 3 to configure the positioning of the containers 2 in relation to the optical systems 320. The central control unit 12 then allows to automatically manage the vertical movement of the containers 2 and / or the marking stations 3, in particular according to the format of the containers 2.

[0100] In embodiments, the central control unit 12 allows setting the mark 310 to be affixed to the zones 20, 20a, 20b of a container 2.

[0101] An operator can enter the various parameters at the level of a dedicated interface of the central control unit 12, or possibly remotely. For these purposes, the central control unit 12 may include a control screen for the installation 100 with a dedicated human-machine interface allowing the entry of information, for example the entry of the container format 2, the choice of the brand 310, etc.

[0102] The invention also relates to a method for marking containers 2 comprising at least the following steps: - a first step E1 consisting of performing a treatment on said containers 2, - a second step E2 consisting of rotating said containers 2 around a vertical axis around which laser marking stations 3 are rotated, in a manner synchronized with said containers 2, and - a third step E3 consisting of marking said containers 2 during rotation.

[0103] In embodiments, the process is implemented by the device 1 of the invention as described above. Device 1 according to the invention is therefore capable of implementing the marking process of the invention.

[0104] Preferably, the first processing step El is a step of filling and capping the containers 2. Indeed, it has been found that the laser marking with the laser beam 31 is of better quality (in terms of readability in particular) when the container 2 is filled. Indeed, it is generally difficult to use laser systems to mark plastic containers, and particularly PET containers, because laser marking tends to degrade the container due to the high power required to mark containers at a high rate. This can, for example, lead to the formation of holes in the container wall. Advantageously, in some embodiments, the process consists of marking a container 2 filled, preferably with liquid. This allows the liquid to rapidly dissipate the heat from the transmitted laser beam 31 and prevents degradation of the wall of said container 2. The internal integrity of the container 2 in contact with the liquid is thus maintained, while it is possible to generate a strong contrast with high power to achieve a high marking rate and confine the marking to the external surface of the wall of said container 2. Preferably, containers 2 are therefore filled and sealed before being rotated for marking.

[0105] Figure 9 schematically shows the steps of a process according to an embodiment where the containers 2 are filled and sealed during a step EL. Then, according to a possible variant, the filled and sealed container 2 is transferred to the holding members 54, as seen in Figure 9, for example by a gripping means 540 by the neck and a plate 541.

[0106] The grasped containers 2 are then rotated, in a synchronized manner with marking stations 3. Preferably, the rotation step is carried out continuously, without interruption: the container 2 enters the path of the device 1 and is then grasped and rotated.

[0107] During step E3, and during their rotation, the containers 2 are marked.

[0108] Finally, following step E3, the containers 2 are unloaded. Preferably, the containers 2 are unloaded while the carousel 5 is rotating, with the carousel 5 not stopping for this unloading step.

[0109] In some embodiments, the marking step E3 is performed during rotation through an angular sector of less than 360 degrees around the vertical axis. In other words, each container 2 makes approximately one circumvolution, more precisely less than one complete rotation.

[0110] In some embodiments, and as schematically represented in [Fig.8], the method comprises: - after the container processing step El 2, a container loading step El' at a loading point 80, - after the marking step E3, the process includes an unloading step E4 at an unloading point 90 of the containers 2, each station 3 and each container 2 being moved respectively around said vertical axis of rotation between said loading point 80 of said containers 2 and said unloading point 90 of said containers 2 marked at a marking zone 20 before starting a new cycle comprising at least steps E1 to E4.

[0111] Advantageously, after the loading step El' and / or before step E3, the containers 2 are moved vertically. According to a possible embodiment, the laser marking stations 3 are moved vertically during or after said loading step El'. Thus, in embodiments, the containers 2 are moved vertically after loading, in order to adjust the positioning of at least one marking zone 20 opposite the marking stations 3, and in particular opposite the optical output 321 of an optical system 320. The containers 2 are therefore moved from an initial vertical position - or height - to a vertical marking position.

[0112] Preferably, the vertical movement step of the containers 2 takes place during step E2, i.e. during the rotation of the containers 2. Preferably, the rotation step E2 around the X-axis is performed simultaneously with all the other steps of the process. Therefore, the rotation step E2 occurs concurrently with the various steps E1, E3, and E4, with the rotation being continuous. In other words, advantageously, there are no interruptions in the movement of container 2. Then, once the marking step E3 is completed, the containers 2 are again moved vertically back from said vertical position to said initial position so that said containers 2 can be unloaded.

[0113] Containers 2 and / or stations 3 can also be moved during their rotation, during the rotation step E2 and / or during the marking step E3.

[0114] In some embodiments, the marking step E3 is carried out by a pulsed laser in the near-infrared.

[0115] In some embodiments, the marking process includes an additional step, after the marking step E3, of inspecting the marked containers 2.

[0116] The marking process can be implemented in an installation 100 as described above.

[0117] Thus, the invention relates to a particularly efficient container marking device 1 for containers 2, which not only allows for high-quality marking but also at a high rate. It is therefore no longer necessary to stop the movement of the container 2 to be marked, which directly and favorably impacts the operating rate of the industrial line.

Claims

1. Demands Device (1) for laser marking containers (2), said containers (2) being bottles or flasks made of thermoplastic material, of the type comprising at least one body (23), a shoulder (24) extending from said body (23) at an upper end thereof, a neck (21) extending from the shoulder (24), and a base (22) at the lower end of said body (23), said device (1) comprising at least: - a plurality of laser marking stations (3), each station (3) comprising along an optical path at least one laser marking optical head (30) equipped with a laser head unit (300) and an optical system (320) for focusing a laser beam (31) to generate a mark (310) at the level of at least one marking zone (20) of each container (2) to mark said zone (20), - control means (4) connected to the marking stations (3) and comprising a laser processing device (40) and power supply means (41) for the laser marking stations (3), characterized in that it comprises a carousel (5) with a vertical axis of rotation X driven in rotation by at least one motor relative to a frame (7) via a bearing means (70), said carousel (5) comprising at least: - a first platform (50), said first platform (50) supporting a plurality of retaining elements (54) for positioning said container (2) along an axis substantially parallel to the vertical axis of rotation X of said carousel (5), - a barrel (53) supporting the plurality of marking stations (3) such that each optical system (320) is located opposite a container (2) held by a holding member (54), such that said marking stations (3), said control means (4) and said containers (2) are driven in rotation in a synchronized manner with respect to said frame (7), said containers (2) being marked during their rotation, and characterized in that: - the laser marking station (3) is capable of emitting a laser beam (31) of different wavelengths, and is for example of the Ytterbium, Erbium, Thulium fiber laser type, or of the Nd-YAG or Nd:YV04 solid type.

2. Marking device (1) according to claim 1, characterized in that the working distance (D2) between the axis of the container and at least one optical head (30) is constant or substantially constant.

3. Device (1) according to claim 1 or 2, characterized in that at least one optical head (30) of each marking station (3) is capable of moving the focal point of the laser beam (31) in a horizontal plane and / or in a vertical plane and / or in a longitudinal plane relative to at least one marking zone (20).

4. Device (1) according to any one of the preceding claims, characterized in that the shaft (53) comprises means for vertically moving each marking station (3) or each optical head (30), so that each of said stations (3) or each of said optical heads (30) can move vertically along said shaft (53).

5. Device (1) according to any one of the preceding claims, characterized in that the first tray (50) and / or each retaining member (54) comprises means for vertically moving a container (2).

6. Device (1) according to any one of the preceding claims, characterized in that the carousel (5) comprises a second platform (51), referred to as the lower platform, said lower platform being located below the first platform (50), referred to as the upper platform, and driven in rotation in a synchronous manner with said second platform (51), and in that, for each container (2), the retaining members (54) comprise, on the one hand, at the level of the upper platform, a gripping means (540) for retaining a container (2), preferably by the neck (21) and, on the other hand, at the level of said lower platform, a plate (541) on which the bottom (22) of said container (2) rests.

7. Device (1) according to any one of the preceding claims, characterized in that the carousel (5) comprises a third platform (52) whose axis of rotation is coaxial with the axis of rotation of the first platform (50), said third platform (52) supporting the control means (4).

8. Device (1) according to any one of the preceding claims, characterized in that the first tray (50), and / or the second tray (51) and / or the barrel (53) are of one piece.

9. Device (1) according to any one of the preceding claims, characterized in that the control means (4) are located on the upper part of the third plate (52).

10. Device (1) according to any one of the preceding claims, characterized in that each marking station (3) comprises two optical heads (30), placed head to tail in each of said stations (3) so that the optical systems (320) of the two optical heads (30) are superimposed in order to simultaneously mark a marking area (20a) located in the upper part of the container (2) and an area (20b) located in the lower part of said container (2).

11. Device (1) according to any one of the preceding claims, characterized in that each marking station (3) comprises a pulsed laser optical head (30) having a wavelength of between 800 and 2000 nanometers.

12. Installation (100) comprising - a laser marking device (1) according to claims 1 to 11, - a container (2) processing station (10) located upstream of said device (1), said processing station (10) supplying said device 1 directly or indirectly by means of a transfer wheel (8) at a loading point (80), - a transfer wheel (9) at a discharge point (90) to release said containers (2) marked directly or indirectly at a downstream conveying means (101).

13. Installation (100) according to the preceding claim, characterized in that it comprises an inspection system (11) for marked containers (2).

14. A method for marking containers (2), said containers (2) being bottles or vials made of thermoplastic material, comprising at least the following steps: - a first step (E1) consisting of performing a treatment on said containers (2), preferably filling and capping said containers (2), - a second step (E2) consisting of rotating said containers (2), preferably filled and capped, around a vertical axis around which laser marking stations (3) are rotated, in a manner synchronized with said containers (2), and - a third step (E3) consisting of marking said containers (2) during rotation, process characterized in that: - the marking step (E3) is carried out by a pulsed laser in the near infrared.

15. Marking method according to the preceding claim, characterized in that the marking step (E3) is carried out during rotation over an angular sector of less than 360 degrees around the vertical axis.

16. A method for marking containers (2) according to claim 14 or 15 further comprising: - after the step (E1) of processing a container (2), preferably of filling and capping, a step of loading (E1') the containers (2) at a loading point, - following the marking step (E3), an unloading step (E4) at a discharge point of said containers (2), the step (E3) being carried out between said loading point of said containers (2) and said discharge point of said containers (2) marked at at least one area (20) referred to as marking before resuming a new cycle comprising at least the steps (E1) to (E4).

17. A method according to any one of claims 14 to 16, characterized in that, after the loading step (E1') and before or during the marking step (E3), said containers (2) are moved vertically.

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