Mechanical autofocus laser marking apparatus and method

Abstract

Apparatus and method for mechanical autofocus laser marking. Contents of the summary.The invention relates to a laser marking device comprising: - a frame (4) supporting a laser beam emission device (3) which is directed inside a sleeve having a head (11) extended by a protective tube (12); - a detection system for when the protective tube is against the head of the sleeve and the surface (2a) to be marked; - the emission device is mounted on the frame by means of a sliding connection allowing translational movement between the frame and the emission device; - a displacement system (6) for moving the emission device relative to the frame, relative to the head of the sleeve and the surface of the part to be marked, by an additional stroke; - a damping system mounted between the emission device (3) and the frame (4) to absorb at least the additional stroke. Figure for the abstract: Fig. 1.

Description

Title of the invention: Apparatus and method for mechanical autofocus laser marking. Technical field

[0001] The present invention relates to the technical field of devices enabling marking, by means of a laser beam, of the surface of a part in the general sense, of all types of materials, from plastic to metal parts for example.

[0002] The object of the invention finds particularly advantageous applications for ensuring the marking of surfaces that are difficult to access or that require flexibility in the movement or positioning of the laser device. Previous technique

[0003] The prior art includes numerous laser beam marking devices. Generally, a laser marking device comprises a frame supporting a laser beam emission device for marking the workpiece. The laser beam emission device typically includes a laser head emitting a collimated laser beam towards a galvanometer head equipped, at its output, with a focusing lens that concentrates the power to a point located in the focal plane. The workpiece or the laser beam emission device is moved using a robotic or other type of movement system to align the surface to be marked with the focal plane. Positioning the surface to be marked in the focal plane allows for marking with optimized quality. Therefore, it becomes necessary to adjust the focal length of the laser beam to control the marking quality.

[0004] Adjusting the correct distance from the workpiece can be achieved in various ways, for example, using optical pointers or motorized or manual movement systems. While such solutions are satisfactory for fixed marking devices, they cannot be implemented for applications requiring a high degree of compactness, difficult access to the marking area, movement of the marking device, or flexibility in movement or positioning between the marking area and the marking device. Furthermore, for safety reasons, the laser beam must be protected between the laser device's output and the surface to be marked. It is therefore known to equip the laser device with a sheath inside which the laser beam is routed. The sheath has a head extended by a protective tube with one end free to bear against the surface to be marked.The free end of the protective tube defines an outlet section for the . laser beam which is adapted to be pressed against the part following the application of a support force, resulting from the relative displacement between the part and the marking device.

[0005] In practice, a real difficulty arises in guaranteeing the correct focal length for each part positioning, taking into account the manufacturing tolerances of the parts and the positioning uncertainties related to the movement system. To try to meet this need, it is known to equip the end of the protective tube with contact probes whose movements are detected by sensors mounted on the head of the sleeve. Besides the fact that this solution is bulky and expensive, it does not guarantee the positioning of the surface to be marked in the laser's focal plane, particularly due to the uncertainty related to the degree of probe penetration. Description of the invention

[0006] The object of the invention aims to remedy the disadvantages of the prior art by proposing a device for laser marking of a surface, presenting total safety and limited bulk while guaranteeing the marking of the surface positioned in the focal plane.

[0007] To achieve this objective, the device according to the invention comprises a chassis supporting a laser beam emission device for marking the workpiece. The laser beam emission device is provided with a sheath inside which the laser beam is directed along a marking direction. The sheath has a head extended by a protective tube having a free end that rests on the surface to be marked. The free end of the protective tube defines an exit section for the laser beam adapted to be pressed against the workpiece following the application of a pressing force applied substantially parallel to the marking direction. According to the invention: - the protective tube has, opposite its free end, a stop surface; - the head of the sheath has a support surface for the protective tube; - the laser beam emission device is mounted on the chassis via a sliding link allowing a translational movement parallel to the marking direction between the chassis and the laser beam emission device; - a detection system is adapted to detect when the protective tube is, on the one hand, against the bearing surface of the sheath head and, on the other hand, against the surface to be marked; - a displacement system to, when the protective tube is against the bearing surface of the sheath head and the surface to be marked, move relatively the laser beam emission device relative to the chassis, according to an additional stroke of a given value, carried out in the direction maintaining the application of the bearing force on the sheath; - a damping system is mounted between the laser beam emitting device and the chassis to absorb at least the additional travel between the laser beam emitting device and the chassis.

[0008] According to one example, the displacement system is configured to move the laser beam emission device relative to the chassis, according to an additional stroke of a given value between 5 mm and 40 mm.

[0009] It should be noted that the displacement system moves the laser beam emission device relative to the chassis, according to the additional stroke either from a programmed displacement stroke or from a sensor detecting the relative displacement of the laser beam emission device relative to the chassis, according to the additional stroke.

[0010] According to a first preferred embodiment, the protective tube and the sheath head are mounted to move in translation relative to each other along a sliding link parallel to the marking direction, a damping device being mounted between the protective tube and the sheath head to dampen the butting of the protective tube on the bearing surface of the sheath head.

[0011] According to this first embodiment, the detection system is configured to detect when the stop surface of the protective tube comes into contact with the bearing surface of the sheath head.

[0012] Advantageously, the detection system is configured to detect the presence of a drawer equipped with a protective glass for the laser beam emission device.

[0013] According to a second embodiment, the protective tube and the sheath head are mounted fixed in translation relative to each other, the detection system being configured to detect the displacement of the laser beam emission device relative to the chassis.

[0014] To secure the laser marking operation, the detection system is connected to the laser beam emission device to allow the laser beam to be emitted if the protective tube is, on the one hand, against its stop surface, on the support surface of the sheath head and, on the other hand, against its free end on the surface to be marked.

[0015] Advantageously, the detection system is connected to the laser beam emission device to allow the laser beam to be emitted in the presence of the protective glass drawer and if the protective tube is, on the one hand, against its abutment surface on the bearing surface of the sleeve head and, on the other hand, against its free end not resting on the surface to be marked.

[0016] To facilitate the adaptation of the device to the type of part to be marked, the protective tube is mounted on the head of the sheath using a removable assembly system to allow the mounting on the head of the sheath of protective tubes of different types.

[0017] Another object of the invention is a method for laser marking a surface, using an apparatus comprising a chassis supporting a device for emitting a laser beam to mark the part, the laser beam emitting device being provided with a sleeve inside which the laser beam is routed in a marking direction, the sleeve comprising a head extended by a protective tube having a free end that bears on the surface to be marked, the free end of the protective tube defining an exit section for the laser beam, the method comprising the following steps: - ensure a relative movement between the surface to be marked and the device so that the free end of the protective tube is in contact with the surface and that the stop surface of the protective tube is in contact with the support surface of the head of the sheath; - detect when the protective tube is, on the one hand, against the surface to be marked, by its free end against the surface to be marked, and on the other hand, against the support surface of the head of the sheath; - continue the relative movement between the surface to be marked and the device according to an additional stroke of a given value, carried out in the direction maintaining the application of the support force on the sheath; - to dampen at least the additional travel between the laser beam emission device and the chassis. Brief description of the drawings

[0018] [Fig-1] The [Fig. 1] is a perspective view showing an example of the implementation of a laser marking device according to the invention for marking the surface of a part.

[0019] [Fig.2] Fig.2 shows a side view of a first example embodiment of a laser marking device according to the invention, in a resting position to mark the surface of a part.

[0020] [Fig. 3] Fig. 3 shows a side view of a first example embodiment of a laser marking device according to the invention, in a position to make contact with the surface of the part to be marked.

[0021] [Fig.4] Fig.4 shows a side view of a first example embodiment of a laser marking device according to the invention, in final position to mark the surface of a part.

[0022] [Fig. 5] Fig. 5 is a longitudinal sectional view of the first example of a Installation of the laser marking device illustrated in figures 2 to 4.

[0023] [Fig. 6] Fig. 6 is a perspective view showing an example of a device laser marking according to the invention adapted to receive three different types of protective tube.

[0024] [Fig.7] Fig.7 is a partially torn perspective view showing the first example of an embodiment of the laser marking device according to the invention, in which a drawer of the protective glass is in the open position.

[0025] [Fig.8] Fig.8 is a perspective view, partly torn from a detail of the laser marking device illustrated in [Fig.7] and showing a detection system with the protective glass drawer in the open position.

[0026] [Fig.9] Fig.9 is a perspective view, partly torn from a detail of the laser marking device illustrated in [Fig.7], showing a detection system with the protective glass drawer in the closed position.

[0027] [Fig. 10] The [Fig. 10] is a perspective view partly torn from a detail of the laser marking device according to the invention, showing a damping system mounted between the laser beam emission device and the chassis.

[0028] [Fig. 11] The [Fig. 11] is a side cross-sectional view of the damping system illustrated in [Fig. 10], occupying its resting position.

[0029] [Fig. 12] The [Fig. 12] is a side cross-sectional view of the damping system illustrated in [Fig. 10], occupying its compensating position.

[0030] [Fig. 13] Fig. 13 is an elevation view of a second embodiment of a laser marking device according to the invention, whose compensation system is in the rest position.

[0031] [Fig.14] Fig.14 is an elevation view of a second embodiment of a laser marking device according to the invention, whose compensation system is in the compensation position. Description of the implementation methods

[0032] As can be seen from the drawings, the object of the invention relates to an apparatus 1 for making a marking by means of a laser beam on a surface 2a of a part or object 2 in the general sense. The apparatus 1 comprises a laser beam emission device 3 adapted to make a marking in the general sense on the surface of the part 2. The emission device 3 is supported by a frame 4 made in any suitable manner, being fixed or mobile depending on the intended application. In the example illustrated in the drawings, the emission device 3 is mounted on a fixed frame 4, while the part 2 is mounted on a mobile carriage 5 allowing the part 2 to be moved in order to position the surface 2a to be marked in the focal plane. Laser beam alignment. Of course, a reverse arrangement is possible in which part 2 is fixed while device 1 is supported by a mobile chassis 4 moved by a trolley or a robot, for example. It should be understood that device 1 and part 2 are used with a movement system 6 that ensures the relative proximity between device 1 and part 2 to bring device 1 into contact with part 2, as will be explained in detail later in the description. This movement system 6 can take various forms (trolley or robot, for example), with manual or, preferably, motorized movement.

[0033] Conventionally, the emission device 3 comprises a laser head 7 emitting the collimated laser beam towards a galvanometer block 8 equipped at its output with a focusing lens that concentrates the power to a point located in the focal plane P. The laser beam is displaced by the galvanometer block 8 in two perpendicular directions to produce a two-dimensional marking. The emission device 3 is not described in more detail because it is not part of the object of the invention and is well known to those skilled in the art. By way of example, the emission device 3 is a fiber laser source doped with ytterbium.

[0034] The emission device 3 is provided with a sheath 10 inside which the laser beam is conveyed to the surface to be marked 2a, in a marking direction X. The sheath 10 has a head 11 extended, opposite the galvanometer block 8, by a protective tube 12. The head 11 is in the form of an open housing to receive the laser beam from the galvanometer block 8. The head 11 of the sheath communicates with the inside of the protective tube 12 by means of a plate 1 mounted integrally with the head 11 and designed to have a central opening to allow the laser beam to pass inside the protective tube 12 ([Fig. 5]). This plate 1 of the head 11 defines, in the direction of the protective tube 12, a support surface 11b.

[0035] Conventionally, the head 11 of the sleeve 10 comprises a protective glass 13 for the galvanometer block 8, mounted to allow the laser beam to pass through while sealing the protective tube 12 to prevent the passage of dust or fumes from the laser marking operation ([Fig. 7]). Advantageously, the protective glass 13 is mounted on a sliding drawer 14, allowing the protective glass 13 to be cleaned or replaced. The drawer 14 is thus guided in translation within the head 11 in a direction perpendicular to the marking direction X. A duct 15 connected to a suction system opens into the head 11 between the protective glass 13 and the protective tube 12 to extract the dust and fumes from the laser marking operation.

[0036] The protective tube 12 has a free end 12a defining an exit section for the laser beam. The protective tube 12 is designed to bear, by its free end 12a, against the surface 2a to be marked, being pressed against the part 2 following the application of a bearing force applied substantially parallel to the marking direction X. The bearing force is obtained as a result of the relative approach between the marking device 1 and the object 2, by means of the displacement system 6. According to a preferred embodiment, the free end 12a of the protective tube is equipped with a sealing gasket 12b.

[0037] According to an advantageous embodiment, the protective tube 12 is mounted on the head 11 of the sleeve using a removable assembly system 17-20 to allow the mounting of different types of protective tubes 12 on the head 11 of the sleeve. As is clear from [Fig. 6], each protective tube 12 has different dimensions, or more precisely, a cross-section with dimensions adapted to the marking to be performed. Thus, the protective tube 12 can have a square, rectangular, or circular cross-section that can be configured to different dimensions. The removable mounting of the protective tube 12 on the head 11 of the sleeve makes it easy to adapt the marking device to the part 2 and the marking to be performed.

[0038] The removable assembly system 17-20 can be implemented in various ways. In the illustrated example, the removable assembly system comprises assembly screws 17 passing through passages 18 formed in a base 19 extending transversely from the end of the protective tube 12 opposite the free end 12a. The assembly screws 17 are designed to be anchored in tapped holes formed in a plate 21 supported by the head 11. The protective tube 12 is thus rigidly assembled to the plate 21, which, of course, has a passage for the laser beam in its central part.

[0039] The protective tube 12 thus presents, opposite its free end of support 12a, by its plate 21, a stop surface 23 directed towards the support surface 11b presented by the plate 1la of the head 11 of the sleeve 10. According to a feature of the invention, the protective tube 12 is mechanically stopped by its stop surface 23, on the support surface 11b of the head 11 of the sleeve 10, during the marking operation, as will be explained in detail in the rest of the description.

[0040] According to a first preferred embodiment illustrated in Figures 1 to 12, the protective tube 12 and the head 11 of the sleeve 10 are mounted to move in translation relative to each other by means of a sliding joint 26, 27 parallel to the direction of marking X. According to a second embodiment illustrated in Figures 13 and 14, the protective tube 12 and the head 11 of the sleeve 10 are fixed together, without relative movement between them. According to this second embodiment, the plate 21 of the tube protection 12 is fixed by all means, to the plate 1 of the head 11 of the sleeve 10. According to this second example, the protective tube 12 is also in mechanical contact by its abutment surface 23, on the bearing surface 11b of the head 11 of the sleeve 10.

[0041] According to the first embodiment, a damping device 28 is mounted between the protective tube 12 and the head 11 of the sleeve to dampen the impact of the protective tube 12 against the bearing surface 11b of the head 11 of the sleeve. The sliding connection 26, 27 and the damping device 28 arranged between the protective tube 12 and the head 11 of the sleeve can be made in any suitable manner.

[0042] In the example illustrated in the drawings (Figures 5 and 8), the sliding joint comprises four guide rings 26 mounted integrally with the plate 1 of the head 11 at each of its corners. Each ring 26 provides support and translation for a pin 27 mounted integrally with the protective tube 12. Each pin 27 has a tubular body 27a cooperating with a guide ring 26. The tubular body 27a is provided at one end with a threaded portion 27b extending into a head 27c inserted into a recess 21a of the plate 21, which has a tapped hole cooperating with the threaded portion 27b of the pin 27.

[0043] The ends of the opposite pins 27 of the head 27c are provided with plates 27d as shown in [Fig.8]. More specifically, the ends of two plates 27d are fixed to two pins 27 aligned in a direction parallel to the sliding direction of the drawer 14. Between the plate 1la and the plates 27d are mounted, as a damping device, springs 28 configured to move the stop surface 23 away from the bearing surface 11b, in the absence of a bearing force on the free end 12a of the protective tube 12. When a bearing force F is applied to the free end of the protective tube 12, the protective tube 12 is moved in translation along the axis marked X towards the plate 1la of the head 11, with the movement damped by the springs 28. The protective tube 12 approaches the head until its stop surface 23 comes into contact with the bearing surface 11b of the plate lia.

[0044] According to one feature of the invention, when the protective tube 12 is abutted, on the one hand, by its abutment surface 23, against the support surface 11b of the sheath head, and on the other hand, by its free end 12a against the surface 2a to be marked, then this surface 2a to be marked is located in the focal plane P of the laser beam. In other words, the laser beam is adjusted so that the focal plane P of the laser beam is positioned at the level of the free end 12a of the protective tube 12 when the protective tube 12 is abutted, by its abutment surface 23, against the support surface 11b of the sheath head. This laser beam adjustment operation is advantageously carried out at the factory on a test bench. It is to Note that for the second embodiment example, it is when the protective tube 12 is fixed onto the head 11 that the free end 12a is positioned in the focal plane P.

[0045] According to another feature of the invention, the device 1 includes a detection system 30 for when the protective tube 12 is, on the one hand, abutted by its abutment surface 23 against the support surface 11b of the sheath head and, on the other hand, abutted by its free end 12a against the surface 2a to be marked. In other words, the detection system 30 detects when the surface to be marked 2a is positioned in the focal plane P of the laser beam. According to the first embodiment, the detection system 30 is configured to detect when the abutment surface 23 of the protective tube 12 comes into contact with the support surface 11b of the sheath head 11 ([Fig. 5]). In this abutment position, the surface to be marked 2a is positioned in contact with the free end 12a of the protective tube.It should be noted that, according to the second embodiment, the protective tube 12 is, by design, abutted by its abutment surface 23 against the bearing surface 11b of the sleeve head. Therefore, the system 30 detects this position, as well as the abutment of the free end 12a of the protective tube against the surface 2a, by detecting the relative displacement between the device 1 and the frame 4, as will be explained later in the description.

[0046] The detection system 30 can be implemented in any suitable manner by employing any type of contact or non-contact detection, such as magnetic, inductive, optical, or other types. In the illustrated example, the detection system 30 comprises a contact detector having a body 30a fixed to the outside of the head, on the plate 21 of the protective tube 12. This detector includes a movable member 30b projecting from the body 30a in order to be actuated when the protective tube 12 is abutted by its stop surface 23 against the bearing surface 11b of the sheath head. In the illustrated example, the movable member 30b is intended to cooperate with a catch 14a mounted integrally with the slide 14 by extending outside the head 11.Thus, when the protective tube 12 comes to rest against the head 11, the movable part 30b comes into contact with the latch 14a, allowing the position of the protective tube 12 against the head 11 of the sheath to be detected.

[0047] Advantageously, the detection system 30 is connected to the laser beam emission device 3. Indeed, when the detection system 30 is activated, the protective tube 12 is against the head 11 of the sleeve on one side and against the surface to be marked by its free end 12a on the other. This means that the surface to be marked is in the correct position and that the laser beam can be safely directed to this surface. This detection system 30, which is in fact a safety sensor, delivers a signal, when activated, authorizing the emission of the laser beam.

[0048] According to an advantageous embodiment, the latch 14a is mounted integrally with the drawer 14 supporting the protective glass 13. It should be noted that the detection system 30 is activated when its movable member 30b is in contact with the drawer 14 in its closed position ([Fig. 9]). If the drawer 14 is in the open position (Figures 7 and 8), particularly for cleaning or changing the protective glass, the latch 14a is completely clear of the movable member 30b of the detection system. In this case, the detection system 30 does not output a signal to authorize the emission of the laser beam. Therefore, the detection system 30 is configured to detect the presence of the drawer 14 equipped with the protective glass. Preferably, the end of the movable member 30b of the detector is provided with a roller 30c facilitating contact with the latch 14a.

[0049] It should be noted that, according to this advantageous embodiment, the detection system 30 is adapted to allow the laser beam to be emitted when the drawer 14 is in the closed position and the protective tube 12 is, on the one hand, abutted by its abutment surface against the bearing surface of the sleeve head and, on the other hand, abutted by its free end against the surface to be marked. With a single detection system 30, it is possible to ensure complete safety during the emission of the laser beam.

[0050] According to another feature of the invention, the laser beam emission device 3 is mounted on the frame 4 by means of a sliding link 33, 34 allowing a translational movement between the frame 4 and the laser beam emission device 3, parallel to the marking direction. This translational movement is necessary because the displacement system 6 is configured so that, when the protective tube 12 is against the head 11 and the surface 2a to be marked, the laser beam emission device 3 is moved relative to the frame 4 by an additional stroke of a given value d, in the direction maintaining the application of the bearing force on the sleeve.This additional stroke is performed to ensure, given the manufacturing tolerances of the parts and the uncertainties in the position and displacement of the movement system 6, that the protective tube 12 is abutted against the head 11 and the surface 2a to be marked. Thus, it is not necessary to assign an exact displacement value to the movement system 6, at the risk of the surface 2a being positioned too far downstream or upstream of the focal plane.

[0051] For example, the displacement system 6 is configured to displace the laser beam emission device 3 relative to the chassis 4, by an additional stroke of a given value d between 5 mm and 40 mm, and for example equal to 10 mm. The displacement system 6 displaces the laser beam emission device 3 relative to the chassis 4, by the additional stroke This can be achieved either from a programmed travel distance or from a sensor detecting the relative displacement of the laser beam emitter with respect to the chassis, according to the additional travel distance. Thus, the movement system 6 can be programmed so that when the protective tube 12 reaches its abutment on the head 11, the detection system 30 detects that the movement system 6 continues its translation along the additional travel distance d. Alternatively, the relative displacement of the laser beam emitter 3 with respect to the chassis 4, beyond the point where the protective tube reaches its abutment on the head, can be detected by a sensor located between the chassis 4 and the emitter 3.

[0052] Of course, the sliding link 33, 34 allowing the additional travel between the chassis 4 and the laser beam emission device 3 can be implemented in any suitable manner. As can be seen in particular from Figures 1 and 10, the sliding link in the illustrated example comprises rails 33 supported by the chassis 4 and cooperating with bearings 34 mounted inside a housing 35 fixed by an adapter plate 35a to the outside of the head 11 of the sleeve.

[0053] According to an advantageous embodiment, a damping system 36 is mounted between the laser beam emitter 3 and the chassis 4 to absorb at least the additional travel d between the laser beam emitter 3 and the chassis 4. This damping device 36 can be implemented in any suitable manner. As can be seen more specifically from Figures 10 to 12, the damping device 36 comprises two tension springs 37 mounted inside the housing 35. Each spring 37 has a first end fixed by a plate 38 to the head 11 of the sleeve and a second end fixed to the chassis 4 by an adjusting rod 39 supported by a bracket 40 extending from the chassis 4.

[0054] Figure 11 illustrates the damping system 36 in its unstressed position, corresponding to the relative position of the device 1 with respect to the chassis 4, illustrated in Figure 3. Figure 12 illustrates the damping system 36 absorbing the additional displacement corresponding to the relative position of the device 1 with respect to the chassis 4, illustrated in Figure 4.

[0055] It is recalled that, according to the first embodiment illustrated in Figures 1 to 12, the protective tube 12 and the head 11 of the sheath 10 are mounted to move in translation relative to each other by means of a sliding joint 26, 27 parallel to the direction of marking X. According to a second embodiment illustrated more particularly in Figures 13 and 14, the protective tube 12 and the head 11 of the sheath are mounted fixed together, without the possibility of translation relative to each other. According to this second embodiment, the detection system 30 is configured to detect the displacement of the laser beam emission device 3 relative to the chassis 4, following the placement of the protective tube 12 on the surface 2a to be marked.

[0056] According to this example, the laser beam emission device 3 is mounted on the chassis 4 via the sliding link 33, 34 described above, which allows movement between the chassis 4 and the beam emission device 3. The detection system 30, as described above, is fixed by its body 30a to the chassis 4, while the movable part 30b is intended to be actuated by the housing 35, as illustrated in [Fig. 14].

[0057] The operation of the device 1 follows directly from the preceding description. In the absence of support on the end 12a of the protective tube, the damping devices 28 and 36 are not stressed (Figures 2 and 13). According to the first embodiment, the distance between the base 19 of the protective tube and the head 11 has a value M in the absence of a bearing force exerted on the protective tube. As explained, the protective tube 12 is forced away from the head by means of the springs 28.

[0058] The movement system 6 is driven to bring the workpiece or device into a position where the surface 2a to be marked is pressed against the free end 12a of the protective tube, crushing the sealing gasket. According to the first embodiment, the application of a support force in the direction F, following the movement performed by the movement system 6, leads to the protective tube 12 being brought against the head 11, with the movement damped by the damping device 28. In this abutment position, the distance between the base 19 of the protective tube and the head 11 has a value Ml less than the distance M. This position is illustrated in [Fig. 3], showing the indentation of the protective tube 12 by a value equal to M-Ml. This abutment position of the protective tube 12 on the head corresponds to the position of the second embodiment illustrated in [Fig. 13].In this position, the damping system 36 is not stressed. Depending on the direction of movement of the device 1 relative to the chassis 4, the edge of the housing 35 is at a distance L from the edge of the chassis 4.

[0059] As already explained, the displacement system 6 is controlled to move the emission device 3 relative to the chassis 4, according to the additional stroke d, carried out in the direction F maintaining the application of the bearing force on the sleeve. This additional displacement d is absorbed by the damping system 36 ([Fig.4], 14).

[0060] The object of the invention also relates to a method for marking the surface of a part using a device 1 described above. For its implementation, a device 1 with the characteristics described above must be made available. The marking method consists of ensuring a relative displacement between the surface 2a and mark and device 1 so that the free end of the protective tube 12 rests on the surface and the stop surface of the protective tube rests on the support surface of the head 11 of the sleeve 10.

[0061] The method then consists of detecting when the protective tube 12 is, on the one hand, abutted by its free end 12a against the surface 2a and, on the other hand, abutted by its bearing surface 23 against the support surface of the sleeve head. In this position, the damping device 36 located between the device 1 and the frame 4 is not stressed. It should be noted that, according to the first embodiment, this abutment occurs for a relative displacement of value M-Ml, considering that the distance between the base 19 of the protective tube and the head 11 has a value M in the absence of a bearing force exerted on the protective tube ([Fig. 2]) and a lower value Ml when the protective tube 12 is, on the one hand, abutted by its free end against the surface to be marked and, on the other hand, abutted against the sleeve head ([Fig. 3]). For example, the relative displacement (M-Ml) is on the order of a few mm, for example 5 mm.

[0062] According to the second embodiment, the protective tube 12 is, by design, abutted by its abutment surface 23 against the bearing surface 11b of the sleeve head. The method automatically detects this position, as well as the abutment of the free end 12a of the protective tube against the surface 2a, by detecting the relative displacement between the device 1 and the frame 4. Indeed, applying a bearing force in direction F on the protective tube leads to a relative displacement of the device 1 with respect to the frame 4. This relative displacement is detected by the detection system 30.

[0063] The method aims to control the displacement system 6 to continue the relative displacement between the surface 2a to be marked and the device 1 by an additional stroke of a given value d, carried out in the direction maintaining the application of the bearing force on the sleeve ([Fig. 4]). The method aims to dampen, using the damping system 36, at least the additional stroke d between the laser beam emission device 3 and the chassis 4. [Fig. 4] illustrates the displacement L-d of the device 1 relative to the chassis 4, considering that when the damping system 36 is not activated, the edge of the housing 35 is a distance L from the edge of the chassis 4 along the direction of displacement.

Claims

Demands

1. Apparatus for laser marking a surface (2a) of a part (2), comprising: - a chassis (4) supporting a laser beam emission device (3) for marking the part, the laser beam emission device (3) being provided with a sleeve (10) inside which the laser beam is routed in a marking direction (X), the sleeve having a head (11) extended by a protective tube (12) having a free end (12a) delimiting an exit section for the laser beam adapted to be pressed against the part following the application of a support force applied substantially parallel to the marking direction, the protective tube (12) having, opposite its free end, a stop surface (23) and the head (11) of the sleeve having a support surface (11b) for the protective tube; - a detection system (30) when the protective tube is, on the one hand, against the bearing surface (11b) of the sheath head by its abutment surface (23) and, on the other hand, against the surface to be marked by its free end (12a), characterized in that: - the laser beam emission device (3) is mounted on the chassis via a sliding link (33, 34) allowing translational movement between the chassis and the laser beam emission device parallel to the marking direction, and in that the device comprises: - a displacement system (6) for, when the protective tube is against the bearing surface (11b) of the head of the sheath and on the surface to be marked, to move the laser beam emission device relative to the chassis, according to an additional stroke of a given value (d), carried out in the direction maintaining the application of the bearing force on the sheath; - a damping system (36) is mounted between the laser beam emission device (3) and the chassis to absorb at least the additional travel between the laser beam emission device and the chassis.

2. Apparatus according to claim 1 wherein displacement system (6) is configured to displace the laser beam emission device (3) relative to the chassis, along a supplementary stroke. comment of a given value between 5 mm and 40 mm.

3. Device according to any one of claims 1 or 2 wherein the displacement system (6) displaces the laser beam emission device (3) relative to the chassis, according to the additional stroke either from a programmed displacement stroke or from a sensor detecting the relative displacement of the laser beam emission device relative to the chassis, according to the additional stroke.

4. Apparatus according to any one of claims 1 to 3 wherein the protective tube (12) and the head (11) of the sheath are mounted movable in translation relative to each other by means of a sliding link (26, 27) parallel to the marking direction, a damping device (28) being mounted between the protective tube (12) and the head (11) of the sheath to dampen the butting of the protective tube on the bearing surface of the head of the sheath.

5. Device according to any one of claims 1 to 4 wherein the detection system (30) is configured to detect when the stop surface of the protective tube comes into contact with the bearing surface of the sheath head.

6. Device according to any one of claims 1 to 5 wherein the detection system (30) is configured to detect the presence of a drawer (14) equipped with a protective glass (13) for the laser beam emitting device.

7. Apparatus according to any one of claims 1 to 3 wherein the protective tube (12) and the head (11) of the sheath are mounted fixed in translation relative to each other, the detection system (30) being configured to detect the displacement of the laser beam emitting device relative to the chassis.

8. Apparatus according to any one of claims 1 to 7 wherein the detection system (30) is connected to the laser beam emission device (3) to allow the laser beam to be emitted if the protective tube (12) is, on the one hand, abutted by its abutment surface, on the bearing surface of the sheath head and, on the other hand, abutted by its free end on the surface to be marked.

9. Apparatus according to claim 6 wherein the detection system (30) is connected to the laser beam emission device (3) to allow emission of the laser beam in the presence of the protective glass drawer (14) and if the protective tube (12) is, on the one hand, abutted by its abutment surface, against the bearing surface of the sheath head and, on the other part, butted by its free end against the surface to be marked.

10. Apparatus according to any one of claims 1 to 9 wherein the protective tube (12) is mounted on the head (11) of the sheath using a removable assembly system (17) to allow the mounting on the head (11) of the sheath, of protective tubes (12) of different types.

11. A method for laser marking a surface (2a) of a part, using an apparatus (1) comprising a frame (4) supporting a laser beam emission device (3) for marking the part, the laser beam emission device having a sleeve (10) inside which the laser beam is directed in a marking direction, the sleeve having a head (11) extended by a protective tube (12) having a free end (12a) for bearing on the surface to be marked, the free end of the protective tube defining an exit section for the laser beam, the method comprising the following steps: - ensure a relative movement between the surface (2a) to be marked and the device so that the free end of the protective tube is in contact with the surface (2a) to be marked and that the stop surface of the protective tube is in contact with the support surface of the head of the sheath; - detect when the protective tube (12) is in contact with the surface to be marked by its free end and in contact with the support surface of the head of the sheath by its stop surface; - ensure between the chassis and the laser beam emission device (3), a translational movement parallel to the marking direction; - continue the relative movement between the surface to be marked and the device by an additional stroke of a given value, carried out in the direction maintaining the application of the bearing force on the sheath - dampen at least the additional travel between the laser beam emission device (3) and the chassis (4).