Tube and profile machining machine, with a system for scanning the cross-section profile of the tube or profile being machined.
By inclining the camera's optical axis to align with the laser beam plane, the scanning system addresses focus issues in laser machining machines, achieving enhanced precision and accuracy in scanning tube and profile cross-sections.
Patent Information
- Application Number
- FR2025002016
- Authority / Receiving Office
- FR · FR
- Patent Type
- Utility models
- Current Assignee / Owner
- Priority Date
- 2024-03-07
- Filing Date
- 2025-02-27
- Publication Date
- 2026-03-06
- Estimated Expiration
- 2035-02-27
AI Technical Summary
Existing scanning systems for laser machining machines face challenges in achieving optimal focus of the machining area due to the need for an infinite depth of field, which results in reduced light capture and image sharpness when the iris is closed to compensate.
The scanning system employs cameras with optical axes inclined at an angle to the camera sensor plane, aligning the focus plane with the laser beam plane to improve image focus using Scheimpflug's law, allowing for optimal focus without reducing light capture.
This configuration ensures improved image focus and accuracy in scanning the cross-sectional profile of tubes and profiles, enhancing machining precision and efficiency.
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Abstract
Description
Title of the invention: Tube and profile machining machine, with a system for scanning the profile of the cross-section of the tube or profile being machined. TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates in general to a tube and profile machining machine, in particular a laser machining machine (for example laser cutting) of tubes and profiles, equipped with a scanning system allowing the profile of the cross section of the tube or profile being machined to be scanned.
[0002] In the following description and claims, the terms "tube" and "profile" are used to identify any elongated article having (with the exception of machining tolerances) a uniform cross-section along its longitudinal axis, the cross-section being of any shape, either closed (e.g., circular, rectangular or square, etc.) or open (e.g., L-shaped, C-shaped, U-shaped, etc.). Previous technique
[0003] The use of scanning systems on machines for laser machining of tubes or profiles in order to detect the geometry of the cross-section of the tube or profile being machined is known.
[0004] In particular, scanning systems are known comprising a pair of laser scanning modules, otherwise called LSMs (Laser Scanning Modules), each module comprising a laser emitter adapted to emit a narrow beam of light onto the tube or profile being machined and a camera adapted to capture an image of the part of the tube or profile being machined, which part is illuminated by the narrow beam of light emitted by the associated laser emitter, and a processing unit adapted to process the images captured by the camera of each laser scanning module in order to reconstruct the entire profile, or at least a part thereof, of the cross-section of the tube or profile being machined.Thanks to the use of such scanning systems, it is possible to know at any time the actual profile of the cross-section of the tube or profile being machined, a profile which, depending on machining tolerances, can deviate more or less considerably from the theoretical profile. It is thus possible, for example, to center the machining operation relative to the actual profile of the cross-section of the tube or profile being machined.
[0005] An example of a laser machining machine for tubes and profiles comprising such a scanning system is known from document EP3233366 in the name of the same applicant.
[0006] According to such a known solution, the machine comprises a laser machining head adapted to emit a laser beam focused on the surface of the tube or profile to be machined and a scanning system adapted to scan the cross-sectional profile of the tube or profile being machined. The scanning system comprises at least one laser scanning module having a laser emitter adapted to emit a narrow beam of light to illuminate an upper portion of the tube or profile being machined and a camera adapted to capture an image of the portion of the tube or profile illuminated by the narrow beam of light. The machining head is mounted in a transposable manner in a transverse direction, that is, in a direction lying in a plane perpendicular to the longitudinal axis of the tube or profile, and preferably also in the vertical direction.At least one laser scanning module is mounted so as to be an integral part of the machining head, at least in the transposition movement along the transverse direction.
[0007] Such a scanning system makes it possible to reconstruct the geometry of the cross-sectional profile of a tube or profile of any shape and size, by exploiting the possibility of transposing the laser scanning module(s) in the transverse direction, as well as the possibility of rotating the tube or profile being machined around its longitudinal axis.
[0008] In such a scanning system, the laser emitter and the camera of each laser scanning module are arranged at a certain distance from each other and at a certain angle between the camera's viewing axis and the propagation axis of the narrow beam of light emitted by the laser emitter. The camera's cone of vision, the dimensions of which depend on the camera and its optical system, intersects the plane of the narrow beam of light emitted by the laser emitter, thus defining the machining area of the laser scanning module. Since the plane of the narrow beam of light is not parallel to the plane of the camera sensor, focusing the entire machining area proves quite complicated. In fact, to achieve optimal focus, an optical system with infinite depth of field, or at least equal to the height of the trapezoid formed by the intersection between the plane of the narrow beam of light and the camera's cone of vision, would be required.With such a scanning system, therefore, the only way to increase the depth of field is to close the iris of the optical system, but this entails the following two disadvantages: .
[0009] - closing the iris reduces the amount of light that can be captured by the optical system, and therefore, to obtain sufficiently clear images, it is necessary to increase the exposure time;
[0010] - considerable closure of the iris can lead to excessive diffraction of the light and a reduction in image sharpness. Summary of the invention
[0011] The object of the present invention is to provide a tube and profile machining machine, in particular a laser machining machine (for example laser cutting) of tubes and profiles, equipped with a scanning system allowing the profile of the cross section of the tube or profile being machined to be scanned, which overcomes the disadvantages of the prior art as described above.
[0012] This object and others are fully realized according to the present invention by a tube and profile machining machine as defined in independent claim Annex 1.
[0013] Advantageous embodiments of the present invention are specified in the dependent claims, the content of which should be understood as forming an integral part of the description that follows.
[0014] In summary, the present invention is based on the idea of using, for each laser scanning module of a scanning system of the type identified above, a camera configured such that the optical axis of the camera is inclined at a certain angle to the direction perpendicular to the plane of the camera sensor (i.e., such that the optical plane of the camera lens is inclined at a certain angle to the plane of the camera sensor), and precisely inclined towards the plane in which the narrow beam of light generated by the laser emitter of the relevant laser scanning module lies. Thus, thanks to Scheimpflug's law, the focusing of the image of the machining area is improved.
[0015] The angle of inclination between the optical axis of the camera lens and the direction perpendicular to the plane of the camera sensor is preferably chosen so that the focus plane of the camera lens coincides with the plane of the narrow beam of light generated by the laser emitter of the relevant laser scanning module, so as to optimize the focus of the image of the machining area.
[0016] The use of a camera configured in this way is clearly a simple and inexpensive solution to the problem of improving the image focus of the machining area. Such a camera can be custom-made to have the desired inclination between the optical axis and the direction perpendicular to the sensor plane, or it can be obtained by modifying an existing camera by inserting of an adapter between the lens and the camera sensor in order to obtain the desired tilt between these two camera components.
[0017] According to one embodiment, the scanning system comprises at least a first laser scanning module and a second laser scanning module which are arranged on opposite sides with respect to a vertical plane passing through the feed axis of the machine.
[0018] The laser scanning modules are preferably arranged so that the narrow beams of light generated by the laser emitters are in the same plane, preferably in the aforementioned vertical transverse plane. BRIEF DESCRIPTION OF THE FIGURES
[0019] Other features and advantages of the present invention will become apparent from the following detailed description, given solely by way of non-limiting example with reference to the accompanying drawings, in which:
[0020] [Fig. 1] is a perspective view, partially showing a machining machine of tubes and profiles, in particular a laser cutting machine for tubes and profiles, equipped with a scanning system enabling the cross-sectional profile of the tube or profile being machined to be scanned, according to an embodiment of the present invention;
[0021] [Fig.2] is a front view of the machine in [Fig.1];
[0022] [Fig.3] is a side view of the machine in [Fig.1];
[0023] [Fig.4] and [Fig.5] are, respectively, a perspective view and a front view schematically showing the arrangement of the laser scanning modules of the scanning system in relation to the tube or profile being machined in the machine of [Fig.1];
[0024] [Fig.6] is a view that shows in detail one of the two laser scanning modules of the scanning system of the machine in [Fig. 1]; and
[0025] [Fig.7] is a diagram of the operating principle of the camera module laser scanning of [Fig.6]. DETAILED DESCRIPTION
[0026] In the following description and claims, the term "longitudinal" is used to identify a direction coinciding with, or parallel to, a machine feed axis (or machining axis), while the term "transverse" is used to identify a direction located on a plane perpendicular to the machine feed axis.
[0027] With initial reference to [Fig. 1], a tube or profile machining machine according to the invention is designated as a whole by M. In the example given here, the machine M is a tube cutting machine, in particular a laser cutting machine. and profiles, but the invention also applies to machines arranged to perform other types of machining on tubes and profiles, for example, welding. Furthermore, the following description will refer to the application of the laser tube cutting machine, but it is clear that it can also be used with profiles. The tubes or profiles on which the machine is capable of working can have cross-sections of various shapes and sizes, for example, circular tubes, square tubes, rectangular tubes, C-profiles, T-profiles, IPE profiles, HEA profiles, etc.
[0028] The machine M comprises, in a manner known per se, a base 10, a machining head 12 adapted to perform machining (in this case cutting) on a tube T by means of a focused laser beam emitted through a laser nozzle 18, a feeding device 14 adapted to advance the tube T along a feeding axis (or machining axis) x, with which the longitudinal axis of the tube T being machined is aligned, and a scanning system adapted to perform a scanning of at least a part (in particular an upper part) of the cross-sectional profile of the tube T. In the embodiment shown, the machine M further comprises a guiding device 16, which is arranged upstream of the machining head 12 and which is capable of guiding the tube T as it is advanced by means of the feeding device 14 towards the machining head 12. However, the guiding device 16 may not be provided.
[0029] With reference also to Figures 2 to 5, the scanning system comprises at least one laser scanning module 20, which in turn comprises a laser emitter 22 adapted to emit a narrow beam of light L to illuminate a portion of the tube T being machined, and a camera 24 adapted to capture an image of the portion of the tube T being machined, which portion is illuminated by the narrow beam of light L emitted by the laser emitter 22. According to the embodiment shown here, the scanning system preferably comprises two laser scanning modules 20, one arranged on one side and the other on the opposite side, with respect to a vertical plane passing through the feed axis x and also arranged above the feed axis x (as can be seen in particular in Figures 2 and 5). However, more than two laser scanning modules may be provided.
[0030] The machining head 12 is movable relative to the base 10 in a transverse plane, that is, in a plane perpendicular to the feed axis x (a vertical plane, assuming that the feed axis x is oriented horizontally). In particular, the machining head 12 is movable in the transverse plane at least in the horizontal direction (indicated by y in Figures 1 and 2 and hereafter also referred to as the transverse direction), preferably both in the horizontal y direction and in the vertical direction (indicated by z in Figures 1 and 2). In this respect, for example, the machining head 12 is supported by a head support structure 26, which is mounted on a slide 28 so as to be transposable in the vertical direction z. In turn, the slide 28 is mounted so as to be transposable in the transverse direction y. The machining head 12 is thus movable in the transverse plane with two degrees of freedom, namely with a transposition degree of freedom in the vertical direction z and with a transposition degree of freedom in the transverse direction y. Furthermore, as envisaged in the embodiment shown, the machining head 12 is preferably (although not necessarily) mounted on the head support structure 26 so as to be able to oscillate about a transversely oriented oscillation axis t (or, according to an embodiment not shown, about two oscillation axes that are orthogonal to each other).A movement of the machining head 12 in a direction parallel to the feed axis x can also be considered.
[0031] The feeding device 14 is preferably arranged to control not only a transposition movement of the tube T along the feeding axis x (advanced movement), but also a rotational movement of the tube T around such an axis. In the case of a laser tube cutting machine, the combination of the degrees of freedom of movement of the machining head 12 (transposition along the transverse direction y and transposition along the vertical direction z, as well as optionally rotation around the oscillation axis t and / or transposition along the direction of the feeding axis x) and the degrees of freedom of movement of the tube T (transposition along the direction of the feeding axis x and rotation around the feeding axis x) makes it possible to perform a cut on the wall of the tube T along any cutting line.
[0032] The two laser scanning modules 20 are mounted on a support structure 30 which is in turn fixed to the slide 28. The laser scanning modules 20 thus move together with the slide 28, and consequently also together with the machining head 12, along the transverse direction y. According to another embodiment (not illustrated), the support structure, on which the laser scanning modules are mounted, is fixed to the head support structure, or in general to a slide on which the machining head is mounted, such that the laser scanning modules are an integral part of the transposition with the machining head in both the transverse direction y and in the vertical direction z.
[0033] In the illustrated embodiment, the support structure 30 has an overall C-shaped configuration, with a cross member 32 that is fixed to the slide 28 and with a pair of longitudinally extending lateral arms 34 that are fixed to the opposite ends of the cross member 32. The respective fixing flanges 36 are securely connected to the free ends of the lateral arms 34. Fixing flanges Similar 38s are each securely connected to one end of a support arm 40 (preferably extending in line with a respective lateral arm 34 and on which the laser emitter 22 and the camera 24 are mounted) of a relevant laser scanning module 20. Each laser scanning module 20 can thus be easily mounted on the support structure 30 by connecting, for example by means of screws, the mounting flange 38 of the relevant support arm 40 to the mounting flange 36 of the relevant lateral arm 34.
[0034] With reference to Figures 4 and 5, each laser emitter 22 is arranged to generate a narrow beam of light L with a certain beam angle α, for example, 20°. Each laser emitter 22 is preferably provided, in a manner known per se, with an optical system to allow uniform diffusion of the light over the entire beam aperture, or at least over most of it. Each laser emitter 22 is preferably mounted such that its optical axis (denoted by oO) lies in the transverse plane. Furthermore, the optical axis Oi of each laser emitter 22 is inclined at a certain angle θ with respect to the horizontal, as shown in [Fig. 5]. The optical axes Oi of the laser emitters 22 of the laser scanning modules 20 are preferably located in the same plane.Even more preferably, the vertical plane in which the optical axes Oi of the laser emitters 22 of the laser scanning modules 20 are located passes through the optical axis oL of the laser beam emitted by the laser nozzle 18 of the machining head 12, when the machining head 12 is arranged such that the optical axis oL of the laser beam emitted by the laser nozzle 18 is oriented vertically. The scanning system thus scans the profile of the tube T precisely at the cross-section in which the laser beam emitted by the laser nozzle 14 of the machining head 12 acts during machining. This clearly ensures the highest possible accuracy.
[0035] Each camera 24 is preferably mounted so that its optical axis (indicated by o2 in Figures 3 and 4) can be coplanar with the optical axis Oi of the laser emitter 22 of the same laser scanning module 20 and can be inclined, relative to the latter, so as to allow the capture of the image of the part of the surface of the tube T being machined, illuminated by the narrow beam of light L emitted by the laser emitter 22. The cameras 24 are connected at least by a suitable data transfer line (not shown, but in any case of a type known per se) to a processing unit (also not shown and also of a type known per se) which is adapted to process the images captured by each camera in order to reconstruct the geometry of the entire profile, or at least a part thereof, of the cross-section of the tube T being machined.
[0036] With reference now to Figures 6 and 7, each camera 24 comprises, in a manner known per se, a lens 42 and a sensor 44, in particular (well (not necessarily) a CMOS sensor. The lens 42 in turn comprises, in a manner known per se, a lens 46 (or, more generally, at least one lens). According to the invention, each camera 24 is configured such that the optical axis o2 of the lens 42 of the camera 24 is inclined at a certain angle (denoted by q>) with respect to a direction (denoted by s) perpendicular to the sensor plane (denoted by PC) of the sensor 44, that is to say, such that the lens plane (denoted by PL) of the lens 46 is inclined at a certain angle q> with respect to the sensor plane PC, and precisely inclined towards the plane (denoted by PW) in which lies the narrow beam of light L generated by the laser emitter 22 of the respective laser scanning module 20. Such an inclination can be obtained, for example, particularly in the case of using a standard camera, by the fact that an adapter 48 is interposed between the lens 42 and the sensor 44.Thus, thanks to Scheimpflug's law, the focusing plane of objective 42 is brought closer to the PW plane of the narrow beam of light L, which improves the focusing of the image of the machining area.
[0037] In particular, as shown in [Fig.7], the angle of inclination q> between the lens 42 and the sensor 44 of the camera 24 is chosen such that the focusing plane (indicated by PM) of the lens 42 coincides with the plane PW of the narrow beam of light.
[0038] The solution proposed here therefore makes it possible to improve the performance of known scanning systems, in particular the known scanning system of the previous document mentioned in the introductory part of this description, thus ensuring optimal focus of the machining area in a simple and inexpensive manner.
[0039] The present invention has been described herein with reference to one of its preferred embodiments. It is understood that other embodiments may be envisaged, which share the same inventive core, as defined in the supporting claims, as that described herein.
Claims
Demands
1. Tube and profile machining machine (T), comprising: - a machining head (12), - a feeding device (14) arranged to advance, one at a time, a tube or profile (T) to be machined along a feeding axis (x) towards the machining head (12), and - a scanning system for scanning the cross-sectional profile of the tube or profile (T) being machined, wherein the scanning system comprises at least one laser scanning module (20) having a laser emitter (22) adapted to emit a narrow beam of light (L) to illuminate at least a portion of the tube or profile (T) being machined and a camera (24) adapted to capture an image of a portion of the tube or profile (T), which portion is illuminated by said narrow beam of light (L),and wherein the camera (24) of said at least one laser scanning module (20) comprises a lens (42) and a sensor (44) configured such that the optical axis (o2) of the lens (42) is inclined at a certain angle (q>) with respect to a direction (s) perpendicular to the sensor plane (PC) of the sensor (44), towards the narrow beam of light (L) generated by the laser emitter (22) of said at least one laser scanning module (20).
2. Machine according to claim 1, wherein said angle of inclination (q>) between the lens (42) and the sensor (44) of the camera (24) is such that the focusing plane (PM) of the lens (42) coincides with the plane (PW) on which the narrow beam of light (L) generated by the laser emitter (22) is located.
3. Machine according to claim 1 or 2, wherein the camera (24) of said at least one laser scanning module (20) includes an adapter (48) interposed between the lens (42) and the sensor (44) so as to tilt the lens (42) relative to the sensor (44) according to said tilt angle (q>).
4. A machine according to any one of the preceding claims, wherein the machining head (12) is mounted in a transposable manner relative to the tube or profile (T) being machined along a horizontal transverse direction, i.e., perpendicular to said feed axis (x), and wherein said at least one laser scanning module (20) is connected to the machining head (12) so as to be an integral part of it in the transposition movement along said horizontal transverse direction.
5. Machine according to claim 4, in which the machining head (12) is mounted in a transposable manner relative to the tube or profile (T) being machined also in the vertical direction.
6. Machine according to claim 5, wherein said at least one laser scanning module (20) is connected to the machining head (12) so as to be an integral part thereof even in the transposition movement in the vertical direction.
7. Machine according to any one of the preceding claims, wherein the scanning system comprises at least a first laser scanning module (20) and a second laser scanning module (20) which are arranged on opposite sides with respect to a vertical plane passing through said feed axis (x).
8. Machine according to any one of the preceding claims, wherein the laser scanning modules (20) are arranged such that the narrow beams of light (L) generated by the respective laser emitters (22) are in the same plane (PW), in particular in a vertical transverse plane, i.e. perpendicular to said feed axis (x).
9. Machine according to any one of the preceding claims, wherein the machining head (12) is configured to emit a focused laser beam enabling machining, in particular cutting, to be performed on the tube or profile (T).