Method and device for laser-marking containers
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-06-03
- Publication Date
- 2026-04-08
Smart Images
Figure 1 
Figure 2 
Figure 3
Abstract
Description
[0001] DESCRIPTION
[0002] Method and device for laser marking containers
[0003] Technical area
[0004] The invention relates to a method for operating a device with a container conveyor and a laser marking system. The invention also relates to a device for laser marking containers.
[0005] Technical background
[0006] Traditionally, containers are mostly equipped with labels. Typical variants are paper or plastic labels, which are applied to the containers using hot or cold glue or self-adhesive.
[0007] Labels can be problematic in the recycling process, e.g., due to the printing ink used, waterproof paper, glue, etc. In the context of the increasing global sustainability discussions, various technology-inherent characteristics can be viewed as disadvantageous. These include, in particular, the use of plastics for container decoration, a poor carbon footprint during label production (especially plastics) and logistics to application (especially shrink sleeves), and limited recyclability in conventional waste streams. Similar issues can also be cited for direct printing processes.
[0008] In principle, it is therefore desirable to do without labels altogether. Required information could, for example, be marked or written directly onto the containers using a laser marking system. Such a technology is already being used, for example, to laser mark a production number or a best-before date. During laser marking, the laser beam and the resulting heat on the container's surface can cause a physical change in the container's surface (e.g., stress whitening in PET containers), allowing the desired characters to be laser-marked onto the surface.
[0009] The invention is based on the object of creating an improved technology for laser marking containers, with which the quality of the laser markings can preferably be improved and the output (=laser-marked containers per hour) can be increased.
[0010] The problem is solved by the features of the independent claims. Advantageous further developments are specified in the dependent claims and the description.
[0011] One aspect of the present disclosure relates to a method for operating a device with a container conveyor and a laser marking system having one or more marking heads for laser marking containers. The method comprises specifying a plurality of parameters comprising a depth of field of the laser marking system, a writing speed of the laser marking system, and a container spacing between two consecutive containers transported by the container conveyor (e.g., by means of an input device from a user). The method further comprises determining at least one target operating parameter for the container conveyor as a function of the plurality of specified parameters (e.g., by means of a processing device).The method further comprises operating the device for laser marking the containers by means of the laser marking system, wherein the container conveyor is operated as a function of the at least one determined target operating parameter (e.g. by means of a control device).
[0012] The method advantageously enables performance- and quality-optimized laser marking of containers. In contrast to the setting of the container conveyor, which depends solely on the writing speed and container distance, the present method also considers the depth of field of the laser marking system as a particularly relevant parameter. This makes it possible, for example, to determine the size of a working field of the laser marking system, which varies depending on the operation of the container conveyor (e.g., container transport speed and container rotation speed). In addition, the quality of the laser marking (e.g., sharpness and legibility, especially of fine, for example, Asian lettering) can be considered, especially with more complex container geometries, since the limited depth of field of the laser marking system is taken into account.In this context, the method can be used particularly advantageously for containers whose area to be marked / labeled deviates from a flat surface and is instead, for example, singly or multiply curved. Overall, the method can thus enable the design of attractive decorations without the use of additional packaging material in performance ranges that correspond to or at least come close to current decoration processes. Preferably, the depth of field (DOF) can specify a distance between the nearest and the farthest point of the laser beam generated by the laser marking system that is imaged or achieved with acceptable sharpness. The depth of field can also be referred to as depth of focus. The depth of field can be specified, for example, in mm.
[0013] Preferably, the writing speed can be specified, for example, as a character writing speed (e.g., specified as characters per second) or as a feed rate / line writing speed (e.g., specified in mm per second). The writing speed can depend on a configuration of the at least one marking head. The writing speed can depend, for example, on the dynamics and speed of the drives of the at least one marking head.
[0014] For example, the container spacing can specify a distance between the container longitudinal axes / container vertical axes of directly consecutive / adjacent containers or between container peripheral surfaces of directly consecutive / adjacent containers that are transported by the container conveyor. The container spacing can correspond to a pitch or a pitch distance of the container conveyor. The container spacing can preferably be a constant. However, it is also possible for the container spacing to be variable, since the containers are transported, for example, by movement devices of a long-stator linear motor drive or a (magnetic) planar motor drive. The container spacing can be specified, for example, in mm or as a mm range. The container spacing can, for example, be between approximately 80 mm and approximately 400 mm.
[0015] Preferably, the container distance can be less than or equal to a maximum width of a marking field of the laser marking system.
[0016] Preferably, the method may be a computer-assisted method.
[0017] Preferably, the at least one operating parameter can be determined in such a way or the container conveyor can be operated in dependence on the at least one determined operating parameter in such a way that the surface elements or surface sections of the respective container to be laser-marked are preferably perpendicular or with a maximum of + / - 20 0 vertical deviation to the laser beam and the surface elements or surface sections are within the
[0018] Depth of field. In one embodiment, the at least one target operating parameter comprises a target container transport speed or a target container transport speed profile (e.g., a speed profile including acceleration(s) and / or deceleration(s), e.g., time-dependent or distance-dependent). This advantageously allows a maximum target container transport speed to be determined for the specified parameters, with which the highest possible output and the desired quality of the laser markings can be achieved.
[0019] In a further embodiment, the container conveyor is designed to rotate the containers around a respective vertical axis of the containers during transport, preferably by means of container holders, particularly preferably turntables, of the container conveyor. This can advantageously make it possible to enlarge the working window by appropriately rotating the containers.
[0020] In one embodiment, the plurality of parameters further comprise a maximum container rotation speed or a maximum container rotation speed profile (e.g., a profile of a maximum rotation speed including acceleration(s) and / or deceleration(s), e.g., time-dependent or distance-dependent) of the containers by means of the container conveyor, and / or the at least one target operating parameter comprises a target container rotation speed or a target container rotation speed profile (e.g., a profile of a rotation speed including acceleration(s) and / or deceleration(s), e.g., time-dependent or distance-dependent) for rotating the containers about a respective vertical axis of the containers. Advantageously, this allows container rotation to be taken into account, namely in such a way that, by taking this into account, the greatest possible output and the desired quality of the laser markings can be achieved.
[0021] In a further embodiment, a machine model (e.g., a simulation and / or empirically determined machine model) representing the device is used to determine the at least one target operating parameter. Preferably, the machine model can represent a kinematics of the container conveyor and a relative arrangement between the one or more marking heads of the laser marking system and the container conveyor. Alternatively or additionally, the machine model can enable a (e.g.,A change in the size of a working window (dependent on the container transport speed and optionally dependent on the container rotation speed) that lies in a marking field of the laser marking system and within which a container marking is actually possible when the respective container moves past the marking field due to a geometry of the container, is to be determined or taken into account, preferably to enable the working window to be maximized. The target operating parameters for the container conveyor can therefore advantageously be determined on the basis of mathematical modeling that contains, for example, all relevant data on the kinematics of the device, the geometric / structural situation, the laser procedure, the container topology and / or print image information. This can also include complex kinematics with superimposed movements of the containers (e.g. feed and rotation around the vertical axis) as well as, for example,topological details of the containers are taken into account.
[0022] In one embodiment, the laser marking system has an adjustable focal length, and the method further comprises determining a target focal length or a target focal length profile for the laser marking system depending on the plurality of parameters, wherein the laser marking system is preferably operated depending on the determined target focal length or the determined target focal length profile during operation of the device. Advantageously, the possibility of adaptively adjusting the focal length not only takes the container topology into account during laser marking, but also opens up the possibility of using an additional factor to optimize the speed of the container conveyor or the device itself. For example, the (adaptive) change in the focal length can enlarge the working window and thus significantly increase the output without any loss of quality, as well as the marking quality.
[0023] In a further embodiment, the machine model is used to determine the target focal length or the target focal length profile.
[0024] In one embodiment, the plurality of parameters further comprise a dimension and / or a number of characters of a laser marking to be applied to the containers by the laser marking system, and / or the plurality of parameters further comprise information (e.g., direction, number, and / or distance from one another) regarding at least one writing vector of the marking head(s) for a laser marking to be applied to the containers. Thus, the operating mode of the laser marking system can advantageously be taken into account when determining the target operating parameters.
[0025] In a further embodiment, the plurality of parameters further comprise a number of the plurality of marking heads, and / or the plurality of parameters further comprise a subdivision of a laser marking to be applied to the containers by the laser marking system into a plurality of sections (e.g., horizontal sections, vertical sections, or grid sections), wherein each section is preferably assigned to one of the plurality of marking heads. This advantageously allows the output to be significantly increased, wherein the determination of the target operating parameters can advantageously take into account the scalability of the laser marking system.
[0026] In one embodiment, the plurality of parameters further comprise a pitch circle diameter of the container conveyor embodied as a rotary conveyor, and / or the plurality of parameters further comprise information about a path of the container conveyor (e.g., information about a straight path, angle of curvature, or pitch circle diameter). Advantageously, this allows the kinematics of the container conveyor to be mapped very precisely and taken into account when determining the target operating parameters, even if these kinematics are comparatively complex, such as in rotary conveyors with rotating container plates.
[0027] In a further embodiment, the plurality of parameters further comprise a position of the marking head or positions of the marking heads, preferably relative to the container conveyor. Alternatively or additionally, the plurality of parameters further comprise a distance between the marking head and the containers transported by the container conveyor transversely to a container transport direction, or distances between the plurality of marking heads and the containers transported by the container conveyor transversely to a container transport direction. This advantageously also allows the structural conditions to be mapped and taken into account.
[0028] In one embodiment, the multiple parameters also include a container diameter, a container shape, and / or a container contour. This advantageously allows for quality and output-optimized results adapted to the container topology when determining the target operating parameter(s). Taking the container topology into account can also advantageously reduce losses in laser marking quality and thus, above all, increase readability even on more complex container geometries.
[0029] In one embodiment, the container conveyor comprises several independently movable movement devices for transporting the containers, preferably driven by a long-stator linear motor drive or a planar motor drive. Preferably, the at least one target operating parameter comprises a target container transport speed profile. This advantageously also allows the potential of independent container mobility to be fully utilized for performance and quality optimization.
[0030] In a further embodiment, the plurality of parameters further comprise at least one parameter detected during operation of the device by means of a preferably camera-supported detection device and / or by means of the laser marking system, namely preferably a, preferably three-dimensional, container surface position of a container to be laser-marked; and / or a, preferably three-dimensional, container orientation of a container to be laser-marked; and / or a distance of a location to be laser-marked on a container to be laser-marked from a lens of the laser marking system.
[0031] Advantageously, the determination of the target operating parameters can be adjusted in real time or on the fly. This allows, for example, container-specific tolerances to be taken into account and enables dynamic laser markings—for example, for different contents from container to container.
[0032] A further aspect relates to a device for laser marking (laser coding) containers. The device comprises a container conveyor for transporting the containers and a laser marking system with at least one marking head arranged to laser mark the containers transported by the container conveyor. The device further comprises a computer system (e.g., with an input device, a processing device, and / or a control device) configured to carry out a method according to one of the preceding claims. Advantageously, the device can achieve the same advantages as those already described with reference to the method.
[0033] Preferably, the device can be included in a container treatment plant for producing, cleaning, coating, testing, filling, closing, equipping and / or packaging containers for liquid media, preferably beverages or liquid foodstuffs.
[0034] For example, the containers can be designed as bottles, cans, canisters, cartons, flasks, etc.
[0035] Preferably, the terms "control device" and "processing device" can refer to electronics (e.g., implemented as a driver circuit or with microprocessor(s) and data memory) that, depending on its design, can perform control tasks and / or regulation tasks and / or processing tasks. Even if the term "control" is used herein, it can also expediently include or mean "regulation" or "control with feedback" and / or "processing." The previously described preferred embodiments and features of the invention can be combined with one another as desired. the characters
[0036] Further details and advantages of the invention are described below with reference to the accompanying drawings. They show:
[0037] Figure 1 is a schematic representation of an exemplary laser marking system;
[0038] Figure 2 is a perspective view of an exemplary laser marking process;
[0039] Figure 3 is a schematic representation of a method for operating a device for laser marking containers;
[0040] Figure 4 shows a section of a visualization of an exemplary machine model;
[0041] Figure 5 shows a section of a visualization of an exemplary machine model;
[0042] Figure 6 shows a section of a visualization of an exemplary machine model;
[0043] Figure 7 shows a section of a visualization (side view) of an exemplary machine model; and
[0044] Figure 8 shows a section of a visualization (top view) of an exemplary machine model.
[0045] The embodiments shown in the figures are at least partially identical, so that similar or identical parts are provided with the same reference numerals and for their explanation, reference is also made to the description of the other embodiments or figures in order to avoid repetition. Detailed en
[0046] Figure 1 shows a laser marking system 10 for laser marking containers 12. The laser marking system 10 can also be referred to as a laser marking system, laser coding system, or laser inscription system. Preferably, the laser marking system 10 can be a CO2 laser marking system, a fiber laser marking system, or a UV laser marking system.
[0047] Preferably, the laser marking system 10 may comprise a laser source 14 and a marking head 16.
[0048] The laser source 14 can be designed, for example, as a laser tube. The laser tube can be sealed. The laser tube can be filled with a gas, e.g., containing CO2, or a gas mixture, e.g., a CO2-N2-He gas mixture. Electrodes can also be arranged in the laser tube. A supply unit can be connected to the electrodes (not shown in Figure 1). The supply unit can supply the laser source 14 with electrical energy. Using, for example, a high-frequency voltage, molecules, e.g., CO2 molecules, in the laser tube can be excited to oscillate and thus emit a laser beam. The laser source 14 can also be referred to as an oscillator.
[0049] The laser beam generated by the laser source 14 can be guided or directed to the marking head 16 directly or via mirrors. It is possible, for example, to arrange a so-called telescope between the laser source 14 and the marking head 16 to expand the laser beam.
[0050] The marking head 16 may preferably include two movable mirrors 18 and 22 and two drives 20 and 24. The marking head 16 may further include a focusing lens 26. The marking head 16 may also be referred to as a coding head, marking head, or writing head.
[0051] The first drive 20 can rotate the first mirror 18 about a first axis (e.g., x-axis). The first mirror 18 can also be referred to, for example, as a movable scanner mirror, e.g., an X-scanner mirror. The second drive 24 can rotate the second mirror 22 about a second axis (e.g., y-axis). The second mirror 22 can also be referred to, for example, as a movable scanner mirror, e.g., a Y-scanner mirror. The first axis and the second axis can preferably run perpendicular to each other.
[0052] The mirrors 18, 22, moved by the drives 20, 24, can direct the laser beam according to the desired laser marking. The laser beam can thus move, for example, in a writing manner across the surface of the container 12. Preferably, the laser beam can move across the surface of the container 12 within the marking field 32 (see Figure 2), which is assigned to the respective marking head 16.
[0053] Before the laser beam hits the surface of the container 12, it can be focused using the focusing lens 26. The focusing lens 26 can also be referred to as a condenser lens. The focusing lens 26 can be an F-theta lens, for example. Depending on the configuration, the focusing lens 26 can be arranged inside or outside the marking head 16.
[0054] It is possible for the laser marking system 10 to have a plurality of marking heads 16. The plurality of marking heads 16 can, for example, be arranged side by side and / or one above the other. For example, two, three, or more marking heads 16 can be included.
[0055] Each marking head 16 can be connected to its own laser source 14, which can emit a laser beam to the respective marking head 16. Accordingly, the laser marking system 10 can have multiple laser sources 14.
[0056] It is also possible for multiple marking heads 16 to receive their respective laser beams from the same laser source 14. For example, a beam splitter can be arranged between the laser source 14 and multiple marking heads 16. The beam splitter can, for example, split a laser beam received from the laser source 14 into multiple laser beams and direct them to the multiple marking heads 16.
[0057] If multiple laser sources 14 are included, they can, for example, be of identical construction. However, it is also possible for the laser sources 14 to be at least partially different in order to achieve different effects (e.g., color effects) when laser marking the containers 12.
[0058] Figure 2 shows a purely schematic and exemplary device 28 for laser marking. The illustrated part of the device 28 has a marking head 16. As already mentioned, the laser marking system 10 can also have multiple marking heads 16, etc. The illustrated part of the device 28 also has a container conveyor 34.
[0059] The arrangement and configuration of the focusing lens 26 can define a so-called focusing field or lens field 30. The lens field 30 can be two-dimensional. For example, the lens field 30 can have a circular shape. Preferably, the lens field 30 can lie in a vertical plane.
[0060] The laser marking system 10 can be designed for laser marking within at least one so-called marking field 32.
[0061] The marking field 32 can be a section of the lens field 30. The section or marking field 32 can include all positions that the laser beam can reach through the movable mirror(s) of the marking head 16. When an area of the container 12 enters the marking field 32, the laser marking system 10 can laser mark the area. When the area of the container 12 exits the marking field 32, the laser marking system 10 can no longer laser mark the area.
[0062] The shape and dimensions of the marking field 32 depend on the mirrors 18, 22 and their mobility, which is effected by the drives 20, 24 (see Figure 1). The marking field 32 can be two-dimensional. For example, the marking field 32 can have a rectangular shape, preferably a square shape. Preferably, the marking field 32 can lie in a vertical plane.
[0063] Each marking head 16 can form or define its own marking field 32 within the respective lens field 30. Multiple marking fields 32 can be at least partially spaced apart from one another and / or at least partially adjacent to one another or overlap one another.
[0064] It is possible for the laser marking system 10 to have an adjustable focal length. For example, the at least one focusing lens 26 and optionally the at least one marking head 16 can be adjustable by means of a preferably motorized adjustment device (not separately shown in Figure 2) in a horizontal plane in a direction perpendicular to a path of the container conveyor 34 and / or perpendicular to the transport direction T in order to adjust a focal length of the laser marking system 10. If there are multiple focusing lenses 26, these and optionally the associated marking heads 16 can be adjusted, for example, jointly or independently of one another by means of the adjustment device.
[0065] It is also possible for the laser marking system 10 to additionally integrate a laser scanning functionality, which can be used to detect the container topology of the containers 12. The container conveyor 34 is designed to transport containers 12. The container conveyor 34 can transport the containers 12 in a transport direction T. Depending on the configuration of the container conveyor 34, it can transport the containers along a desired transport path. The transport path can, for example, be a linear transport path or a curved or arcuate transport path.
[0066] For example, the container conveyor 34 can be a rotary container conveyor (container conveyor carousel). The laser marking system 10 can, for example, be arranged inside or outside the rotary container conveyor. It is also possible for the laser marking system 10 to be arranged partially inside and partially outside the rotary container conveyor. For example, the at least one laser source 14 can be arranged inside the rotary container conveyor, and the at least one marking head 16 can be arranged outside the rotary container conveyor.
[0067] Alternatively, the container conveyor 34 can be, for example, a linear container conveyor. The laser marking system 10 can, for example, be arranged laterally next to the linear container conveyor. The linear container conveyor can, for example, have a preferably revolving conveyor element for transporting the containers 12. The linear container conveyor can, for example, be a belt, strap, chain, or plate conveyor. It is also possible for the linear container conveyor to be designed as a long-stator linear motor container conveyor or a (magnetic) planar motor drive container conveyor, which can move the containers 12 independently of one another by means of movement devices (mover, shuttle).
[0068] The container conveyor 34 can support the containers 12 during transport, preferably at the bottom, the periphery, and / or the mouth. The container conveyor 34 can have container holders 36 (only schematically indicated in Figure 2) for supporting the containers 12. The container holders 36 can preferably hold the containers 12 in base handling or neck handling.
[0069] It is possible that the container conveyor 34 does not have separate container holders 36 and, for example, the containers 12 are simply supported on a preferably revolving conveyor element (e.g., belt, strap, chains or plates) of the container conveyor 34.
[0070] For example, the container holders 36 can each support a container 12. The container holders 36 can, for example, each have a container plate, a centering bell, a container clamp, and / or an inflation device. Preferably, the container conveyor 34 can be configured to rotate the transported containers 12 about their own vertical axis. Preferably, the container holders 36 can be rotatable about their respective vertical axes to rotate the containers 12.
[0071] Optionally, the device 28 may further comprise a detection device 38.
[0072] The detection device 38 can be directed toward the container conveyor 34 or toward the containers 12 transported by the container conveyor 34. The detection device 38 can be arranged upstream of the laser marking system 10 with respect to the transport direction T of the container conveyor 34 or can be integrated into the laser marking system 10. The detection device 38 can, for example, comprise a camera device, an LED detection device, or a laser detection device.
[0073] The detection device 38 can, for example, have a, preferably three-dimensional, container surface position, a, preferably three-dimensional, container orientation and / or a distance of a location to be laser-marked of a container 12 to be laser-marked from the focusing lens 26 of the laser marking system 10.
[0074] Figure 3 shows a purely schematic method for operating the device 28. The method can be used, for example, when commissioning the device 28, during operation of the device 28 and / or during a conversion of the device 28 (e.g. due to a container format change).
[0075] In a step S10, various parameters can be specified. Preferably, the parameters can be specified using a user input device. It is also possible, for example, for the parameters to be received via a communications interface, e.g., from a server.
[0076] In step S10, a depth of field of the laser marking system 10, a writing speed of the laser marking system 10 and a container distance between two consecutive containers 12 transported by the container conveyor 34 are specified as particularly relevant parameters.
[0077] Depending on the design of the container conveyor 34 and the laser marking system 10, further parameters can preferably be specified if desired. The further parameters can, for example, include at least one of: a maximum container rotation speed or a maximum rotation speed profile of the containers 12 (for rotation about their respective vertical axes) by means of the container conveyor 34 or the rotatable container holders 36; a maximum container transport speed of the container conveyor 34; a dimension and / or number of characters of a laser marking (e.g., laser inscription and / or laser decoration) to be applied to the containers 12 by the laser marking system 10;
[0078] Information(s) about writing vectors of the marking head(s) 16 for a laser marking to be applied to the containers 12 (e.g., laser inscription and / or laser decoration); a number of the plurality of marking heads 16; a subdivision of a laser marking to be applied to the containers 12 by the laser marking system 10 into a plurality of sections, wherein each section is preferably assigned to one of the plurality of marking heads 16; a position of the marking head 16 or positions of the marking heads 16, preferably relative to the container conveyor 34; a container diameter, a container shape, and / or a container contour of the containers 12; a preferably three-dimensional container surface position of a container 12 to be laser marked; a preferably three-dimensional container orientation of a container 12 to be laser marked;a distance of a location to be laser-marked on a container 12 to be laser-marked from a focusing lens 26 of the laser marking system 10; a desired angle of incidence at which a laser beam emitted by the laser marking system 10 is to strike a surface of the container 12;
[0079] In a step S12, the predetermined parameters can be processed to determine at least one target operating parameter for the device 28. For example, the at least one target operating parameter can include a target container transport speed or a target container transport speed profile / progression for the container conveyor 34 for transporting the containers 12 and / or a target container rotation speed or target container rotation speed profile for the container conveyor 34 for rotating the containers 12 about their respective vertical axes (e.g., by means of the container holders 36). The at least one target operating parameter can, for example, also include a target focal length for the laser marking system 10. Step S12 can be carried out, for example, using a computer-aided processing device, e.g., remotely or on-site in a container processing plant with the device 28.
[0080] To determine the at least one target operating parameter in step S12, for example, predetermined algorithms, lookup tables, characteristic maps, characteristic curves, etc. can be used, which were determined, for example, empirically through tests and / or simulations.
[0081] Particularly preferably, in step S12, a machine model of the device 28 or a machine model representing the device 28 can be used to determine the at least one target operating parameter.
[0082] The machine model is preferably a mathematical machine model. The machine model can take into account the kinematics of the container conveyor 34 and a relative arrangement between the one or more marking heads 16 of the laser marking system 10 and the container conveyor 34. The machine model can be a simulation model. Preferably, the machine model can contain all relevant data regarding the kinematics of the device 28, the geometric / structural situation of the device 28, the method of the laser marking system 10, the container topology of the containers 12, and laser marking image information(s).
[0083] Preferably, the machine model can be determined empirically through tests and / or simulations.
[0084] It is also possible for the machine model to be a small machine model, which, for example, has an artificial neural network. The small machine model can be supplied with training data for the initial training of the small machine model. The training data can contain several parameter sets with different values for the specified parameters, as well as a suitable value, an optimal value, and / or an unsuitable value for the at least one target operating parameter for the respective parameter set. This training data for the initial training of the small machine model can be determined, e.g., read out, in tests, simulations, and / or from historical operating data of other devices with a container conveyor and laser marking system. It is also possible for certain interdependencies between the specified parameters and / or certain basic conditions to be specified as training data.The Kl machine model can also be self-learning during operation of the device 28, so that, for example, an entered user feedback or a manual or automatic evaluation of a quality of the laser markings on the containers based on recordings of the laser markings on the containers 12 in conjunction with the stored, associated at least one target or actual operating parameter for the container conveyor 34 and / or the laser marking system 10 is taken into account.
[0085] In a step S14, the device 28 for laser marking the containers 12 can be operated using the laser marking system 10. The container conveyor 34 can be operated depending on the determined target container transport speed or the determined target container transport speed profile and, if applicable, on the target container rotation speed or the determined target container transport speed profile determined in step S12. The laser marking system 10 can, if applicable, be operated depending on the determined target focal length.
[0086] For the particularly preferred embodiment with the use of the machine model in step S12, Figures 4ff show exemplary sections and visualizations of the machine model.
[0087] Figures 4 and 5 show a machine model with a representation of the laser marking system (identified by reference numeral 10'), with representations of the containers (identified by reference numeral 12'), a representation of the container conveyor (identified by reference numeral 34') and, by way of example only in Figure 5, a representation of the container holders (identified by reference numeral 36').
[0088] In the machine model, a depth of field (DOF), a distance d between consecutive containers 12', and a writing speed of the laser marking system 10' can be specified. Preferably, a pitch circle diameter t (see Figure 5) and / or a maximum container rotation speed of the container holders 36' (also see Figure 5) can also be specified in the machine model.
[0089] From the specified parameters, a target container transport speed can be determined using the machine model. If the containers 12' can be moved independently of one another in the transport direction, e.g., by using a long-stator linear motor drive or a planar motor drive, a target container transport speed profile can preferably be determined. The target container transport speed profile can specify a transport speed profile of the container in the transport direction as it moves past the laser marking system 10. Preferably, the machine model can also be used to determine a target container rotation speed or a target container rotation speed profile for the rotatable container holders 36'.When determining the target container transport speed, the machine model can, in particular, enable a change in the size of a working window A (see Figures 4 and 5), which lies within a marking field 32 (see Figure 2) of the laser marking system 10 and within which a container marking is actually possible as the respective container 12 moves past the marking field 32, to be determined. The change in size depends on the container transport speed and, optionally, on the container rotation speed.
[0090] The machine model can also accommodate complex kinematics, e.g., if the containers 12' are modeled as rotating around their respective vertical axes and the container conveyor 34' is modeled as a rotary conveyor. The machine model can account for the overlap between the transport movement / feed movement, e.g., linear or on a circular path, and the rotational movement of the containers 12'.
[0091] As already explained with reference to Figure 2, the laser marking system 10 has a (given) marking field 32 in which the laser beam can be moved via mirrors 18, 22. However, the actual working window A of the laser marking system 10' is smaller than this marking field 32 and can result from the writing speed of the laser marking system 10' and the available depth of field (DOF). Skillful coordination of the (target) container transport speed and, if applicable, the (target) container rotation speed can give the laser marking system 10' more time within its marking field 32 and thus generate the largest possible working window A. As a result, the (output) performance (=laser-marked containers per hour) of the device 28 can be increased at the same writing speed. Preferably, the working window A corresponds to the marking field 32 due to the skillful movement coordination.It is preferable to ensure that the operating point of the laser marking system 10' remains in the depth of field.
[0092] Preferably, the distance (e.g., machine pitch) d can also be selected such that, after reaching the end of the working field, the laser beam jumps as seamlessly as possible to the beginning of the working field of the next container 12 to be written. As mentioned, it is possible for this distance d to be variable, e.g., by using flexibly movable movement devices for moving the containers 12.
[0093] It is possible that the machine model enables, by means of mathematical methods, to determine maximum values or maximum profiles for the target container transport speed or the target container transport speed profile and, if applicable, the target container rotation speed or the target container rotation speed profile, taking into account the specified parameters with which the desired laser marking is enabled.
[0094] It is also possible for the machine model to allow individual predefined parameters to be modified in order to determine their influence on the determination of the target container transport speed or the target container transport speed profile and, if applicable, the target container rotation speed or the target container rotation speed profile.
[0095] Figure 6 shows by way of example that the machine model can enable a modeling of a distribution of a laser marking L to be applied to the containers 12 between several marking heads 16.
[0096] For example, the laser marking L can be divided into several (e.g., two or three) sections LI, L2, and L3. The first section LI can be assigned to a first marking head 16 of the laser marking system 10. The second section L2 can be assigned to a second marking head 16 of the laser marking system 10, etc.
[0097] Preferably, the plurality of sections LI, L2, L3 can be arranged one above the other or in rows. Preferably, the plurality of sections LI, L2, L3 can extend parallel. For example, the longitudinal axes of the plurality of sections LI, L2, L3 can extend horizontally.
[0098] It is possible for the multiple sections LI, L2, L3 to be arranged laterally adjacent to one another or in columns (not shown in Figure 6). For example, the longitudinal axes of the multiple sections LI, L2, L3 can extend vertically, preferably parallel.
[0099] It is also possible for the multiple sections LI, L2, L3 to be arranged in a grid, e.g., row- and column-wise, e.g., checkerboard-like (not shown in Figure 6).
[0100] Preferably, the plurality of sections LI, L2, L3 can be formed such that no graphic characters or elements are separated at a boundary between each two sections.
[0101] Figures 7 and 8 show by way of example that the machine model can also allow for an adjustable focal length of the laser marking system 10 to be taken into account.
[0102] Laser marking systems typically operate with a flat-field optics that enables a planar, non-curved focal plane at a defined distance from the laser marking system. The distance between the laser marking system and this focal plane is the focal length. The machine model can allow for an adjustable focal length of the laser marking system 10 to be taken into account. The laser marking system 10 can preferably allow the focal length and thus the distance of the focal plane (or the focal field 30 - see Figure 2) to be dynamically changed, similar to a zoom lens. Using the machine model, a target focal length can be determined in order to adapt the laser marking with the specified depth of field (DOF) (see Figures 4 and 5) to a topology of the containers 12.
[0103] For example, the machine model can be used to output a target focal length depending on the distance of a specific point on the container surface from the laser marking system 10. This can be used to control or regulate the focal point depending on, among other things, the container geometry and information about writing vectors (e.g., path of the writing process, direction, number, etc.) of the laser marking system. This relationship can be applied to the entire working window A (see Figures 4 and 5), i.e., on a 2-dimensional plane. A target focal length profile can also be determined, which can have various target focal lengths for laser marking that can be set one after the other (e.g., time- or path-dependent).
[0104] In Figures 7 and 8, this is visualized in the machine model as an example for a first focal plane Fl at a first focal length bl and for a second focal plane F2 at a second focal length b2.
[0105] The determination of the target focal length or the target focal length profile and their application during operation of the device 28 can be based, for example, on theoretical data (target container data) and / or data measured during operation (actual container data). For example, geometric data relating to the container 12 to be laser-marked can be acquired in real time during operation using the acquisition device 38 and / or the laser marking system 10 itself. For example, a distance to the surface of the container 12 to be marked can be acquired, and the (optimal) target focal length or the (optimal) target focal length profile can then be automatically determined using the machine model and then adjusted during operation.
[0106] The invention is not limited to the preferred embodiments described above. Rather, a multitude of variants and modifications are possible which also make use of the inventive concept and therefore fall within the scope of protection. In particular, the invention also claims protection for the subject matter and features of the subclaims, independent of the claims referred to. In particular, the individual features of independent claim 1 are each disclosed independently of one another. In addition, the features of the subclaims are also disclosed independently of all features of independent claim 1. All ranges referred to herein are to be understood as disclosed in such a way that, as it were, all values falling within the respective range are individually disclosed, e.g. also as preferred, narrower outer limits of the respective range.
[0107] List of reference symbols
[0108] 10 Laser marking system
[0109] 12 containers
[0110] 14 Laser source
[0111] 16 Marking head
[0112] 18 first mirror
[0113] 20 first drive
[0114] 22 second mirror
[0115] 24 second drive
[0116] 26 Focusing lens
[0117] 28 Device for laser marking 30 Lens field
[0118] 32 Checkbox
[0119] 34 Container conveyor 36 Container holder
[0120] 38 Recording device
[0121] A Working field bl, b2 Focal length
[0122] Fl, F2 focal plane
[0123] DOF Depth of Field L Laser Marking
[0124] L1-L3 sections of the laser marking
[0125] S10-S14 Process steps t Pitch circle diameter T Transport direction
Claims
CLAIMS 1. A method for operating a device (28) with a container conveyor (34) and a laser marking system (10) having one or more marking heads (16) for laser marking containers (12), the method comprising: Presetting a plurality of parameters comprising a depth of field (DOF) of the laser marking system (10), a writing speed of the laser marking system (10) and a container distance (d) between two consecutive containers (12) transported by the container conveyor (34); Determining at least one target operating parameter for the container conveyor (34) as a function of the plurality of predetermined parameters; and Operating the device (28) for laser marking the containers (12) by means of the laser marking system (10), wherein the container conveyor (34) is operated as a function of the at least one determined target operating parameter.
2. The method of claim 1, wherein: the at least one target operating parameter comprises a target container transport speed or a target container transport speed profile.
3. Method according to claim 1 or claim 2, wherein: the container conveyor (34) is designed to rotate the containers (12) during transport about a respective vertical axis of the containers (12), preferably by means of container holders (36), particularly preferably turntables, of the container conveyor (34).
4. The method according to any one of the preceding claims, wherein: the plurality of parameters further comprises a maximum container rotation speed or a maximum container rotation speed profile of the containers (12) by means of the container conveyor (34); and / or the at least one target operating parameter comprises a target container rotation speed or a target container rotation speed profile for rotating the containers (12) about a respective vertical axis of the containers (12).
5. Method according to one of the preceding claims, wherein: in determining the at least one target operating parameter, a machine model representing the device (28) is used, wherein preferably: the machine model depicts a kinematics of the container conveyor (34) and a relative arrangement between the one or more marking heads (16) of the laser marking system (10) and the container conveyor (34); and / or the machine model for determining the target operating parameter makes it possible to determine or take into account a change in the size of a working window (A) that lies in a marking field (32) of the laser marking system (10) and within which a container marking is actually possible when the respective container (12) moves past the marking field (32) due to a geometry of the containers (12), preferably to enable maximizing the working window (A).
6. The method according to any one of the preceding claims, wherein the laser marking system (10) has an adjustable focal length and the method further comprises Determining a target focal length or a target focal length profile for the laser marking system (10) as a function of the plurality of parameters, wherein, when operating the device (28), the laser marking system (10) is operated as a function of the determined target focal length or the determined target focal length profile.
7. The method according to claim 5 and claim 6, wherein: the machine model is used in determining the target focal length or the target focal length profile.
8. The method according to any one of the preceding claims, wherein: the plurality of parameters further comprises a dimension and / or a number of characters of a laser marking (L) to be applied to the containers (12) by the laser marking system (10); and / or the plurality of parameters further comprises information regarding at least one writing vector of the marking head(s) (16) for a laser marking (L) to be applied to the containers (12).
9. Method according to one of the preceding claims, wherein: the plurality of parameters further comprises a number of the plurality of marking heads (16); and / or the plurality of parameters further comprises a division of a laser marking (L) to be applied to the containers (12) by the laser marking system (10) into a plurality of sections (LI, L2, L3), wherein preferably each section is assigned to one of the plurality of marking heads (16).
10. The method according to any one of the preceding claims, wherein: the plurality of parameters further comprise a pitch circle diameter (t) of the container conveyor (34) designed as a rotary conveyor; and / or the plurality of parameters further comprise an indication of a path of the container conveyor (34).
11. The method according to any one of the preceding claims, wherein: the plurality of parameters further comprise a position of the marking head (16) or positions of the marking heads (16), preferably relative to the container conveyor (34); and / or the plurality of parameters further comprise a distance between the marking head (16) and the containers (12) transported by the container conveyor (34) transversely to a container transport direction (T) or distances between the plurality of marking heads (16) and the containers (12) transported by the container conveyor (34) transversely to a container transport direction (T).
12. The method according to any one of the preceding claims, wherein: the plurality of parameters further comprise a container diameter, a container shape and / or a container contour of the containers (12).
13. The method according to any one of the preceding claims, wherein: the container conveyor (34) comprises a plurality of independently movable movement devices for transporting the containers (12), preferably driven by a long-stator linear motor drive or a planar motor drive; and the at least one desired operating parameter comprises a desired container transport speed profile.
14. Method according to one of the preceding claims, wherein: the plurality of parameters further comprises at least one parameter detected during operation of the device (28) by means of a preferably camera-supported detection device (38) and / or by means of the laser marking system (10), namely preferably: a, preferably three-dimensional, container surface position of a container (12) to be laser-marked; and / or a, preferably three-dimensional, container orientation of a container (12) to be laser-marked; and / or - a distance of a location of a container (12) to be laser-marked to a lens (26) of the laser marking system (10).
15. A device (28) for laser marking containers (12), the device (28) comprising: a container conveyor (34) for transporting the containers (12); a laser marking system (10) having at least one marking head (16) arranged to laser mark the containers (12) transported by the container conveyor (34); and a computer system configured to carry out a method according to any one of the preceding claims.